WO2024122353A1 - Multilayer film and method for manufacturing same - Google Patents

Multilayer film and method for manufacturing same Download PDF

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Publication number
WO2024122353A1
WO2024122353A1 PCT/JP2023/042085 JP2023042085W WO2024122353A1 WO 2024122353 A1 WO2024122353 A1 WO 2024122353A1 JP 2023042085 W JP2023042085 W JP 2023042085W WO 2024122353 A1 WO2024122353 A1 WO 2024122353A1
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Prior art keywords
easy
layer
film
polymer
adhesion layer
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PCT/JP2023/042085
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French (fr)
Japanese (ja)
Inventor
祐二 柴田
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日本ゼオン株式会社
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Publication of WO2024122353A1 publication Critical patent/WO2024122353A1/en

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  • the present invention relates to a multilayer film and a method for producing the same.
  • Multilayer films that have a base film and a resin layer that contains particles are known (see Patent Documents 1 to 3).
  • the adhesion between the substrate film and the functional layer, such as the optical functional layer may be insufficient.
  • an easy-adhesion layer may be provided on the substrate film to improve the adhesion with the functional layer.
  • particles may be included in the easy-adhesion layer.
  • the film has an easy-adhesion layer containing particles, the adhesion between the base film and the functional layer may be insufficient. Therefore, there is a need for a multilayer film having good adhesion between the base film and other functional layers; and a method for producing such a multilayer film having good adhesion.
  • the present inventors have conducted extensive research to solve the above problems, and have found that the above problems can be solved by a multilayer film including a base film, a specific easy-adhesion layer, an anchor layer, and a top layer, in which the total thickness (T1+T2) of the easy-adhesion layer thickness T1 and the anchor layer thickness T2 is a predetermined value or more, and have completed the present invention. That is, the present invention provides the following.
  • a multilayer film comprising a base film, an easy-adhesion layer provided in direct contact with one surface of the base film, an anchor layer provided in direct contact with the surface of the easy-adhesion layer, and a top layer provided in direct contact with the surface of the anchor layer,
  • the total thickness (T1 + T2) of the thickness T1 of the easy-adhesion layer and the thickness T2 of the anchor layer is 150 nm or more
  • the easy-adhesion layer contains organic particles (NP) having an average particle diameter T3 equal to or greater than the thickness T1 of the easy-adhesion layer, Multi-layer film.
  • the easy-adhesion layer is a cured product of an easy-adhesion layer material containing the organic particles (NP), a polymer (P1) having a (meth)acrylic acid ester unit, and a crosslinking agent (1).
  • NP organic particles
  • P1 polymer having a (meth)acrylic acid ester unit
  • a crosslinking agent (1) any one of the multilayer film described.
  • the anchor layer is a cured product of an anchor layer material containing a polymer (P2) having a (meth)acrylic acid ester unit and a crosslinking agent (2).
  • the easy-adhesion layer is a cured product of an easy-adhesion layer material containing the organic particles (NP), a polymer (P1) having a (meth)acrylic acid ester unit, and a crosslinking agent (1)
  • the anchor layer is a cured product of an anchor layer material containing a polymer (P2) having a (meth)acrylic acid ester unit and a crosslinking agent (2)
  • the multilayer film according to any one of [1] to [6], wherein the polymer (P1) and the polymer (P2) have a common (meth)acrylic acid ester unit.
  • a method for producing the multilayer film according to any one of [1] to [9], A step (1) of preparing a long substrate film; A step (2-1) of applying a liquid adhesive layer material onto the substrate film to form a coating film of the adhesive layer material; A step (2-2) of drying the coating film of the easy-adhesion layer material to form an easy-adhesion layer and obtain a multilayer body (I) having the base film and the easy-adhesion layer; A step (3) of stretching the multi-layered product (I) to obtain a multi-layered product (II); A step (4) of winding up the laminate (II); A step (5-1) of unwinding the wound multilayer material (II) and applying a liquid anchor layer material onto the easy-adhesion layer of the multilayer material (II) to form a coating film of the anchor layer material; A step (5-2) of drying the coating film of the anchor layer material to form an anchor layer, thereby obtaining a multilayer body (III) having the base film, the easy-a
  • the present invention provides a multilayer film having good adhesion between the base film and other functional layers; and a method for producing such a multilayer film having good adhesion.
  • a "long" film refers to a film that is 5 times or more longer than its width, and preferably 10 times or more longer, specifically a film long enough to be wound into a roll for storage or transportation. There is no particular upper limit to the length of the film, and it can be, for example, 100,000 times or less than its width.
  • the slow axis of a film or layer refers to the slow axis in the plane of the film or layer, unless otherwise specified.
  • orientation angle of a film or layer refers to the angle that the slow axis of the film or layer makes with the longitudinal direction of the film or layer.
  • the angle between the optical axes (slow axis, transmission axis, absorption axis, etc.) of each layer in a component having multiple layers represents the angle when the layer is viewed from the thickness direction, unless otherwise specified.
  • the diagonal direction of a long film refers to an in-plane direction of the film that is neither parallel nor perpendicular to the longitudinal direction of the film.
  • nx represents the refractive index in the direction perpendicular to the thickness direction of the layer (in-plane direction) that gives the maximum refractive index.
  • ny represents the refractive index in the in-plane direction of the layer that is perpendicular to the direction of nx.
  • d represents the thickness of the layer.
  • the measurement wavelength is 550 nm, unless otherwise specified.
  • the directions of elements as “parallel,” “vertical,” and “orthogonal” may include an error within a range that does not impair the effect of the present invention, for example, within the range of ⁇ 3°, ⁇ 2°, or ⁇ 1°.
  • a "resin with positive inherent birefringence” refers to a resin whose refractive index in the stretching direction is greater than the refractive index in the direction perpendicular to the stretching direction.
  • a “polymer with positive inherent birefringence” refers to a polymer whose refractive index in the stretching direction is greater than the refractive index in the direction perpendicular to the stretching direction, unless otherwise specified.
  • (meth)acrylic includes “acrylic", “methacrylic” and combinations thereof.
  • (meth)acrylic acid encompasses “acrylic acid,”"methacrylicacid,” and combinations thereof.
  • (meth)acrylonitrile includes “acrylonitrile", “methacrylonitrile”, and combinations thereof.
  • (meth)acrylate encompasses “acrylate,”"methacrylate,” and combinations thereof.
  • a polymerized unit having a structure formed by polymerization of a certain monomer may be expressed using the name of that monomer.
  • a unit having a structure formed by polymerization of a (meth)acrylic acid ester may be referred to as a "(meth)acrylic acid ester unit.”
  • a unit having a structure formed by polymerization of a styrene-based monomer may be referred to as a "styrene-based monomer unit.”
  • a polymer containing a styrene-based monomer unit may simply be referred to as a styrene-based polymer.
  • the structure of the molecule and its components is not limited by the manufacturing method.
  • a layer A is provided in direct contact with one surface of a layer B" means that there is no other layer between one surface of layer B and layer A.
  • a multilayer film according to one embodiment of the present invention includes a substrate film, an easy-adhesion layer provided directly on one surface of the substrate film, an anchor layer provided directly on the surface of the easy-adhesion layer, and a top layer provided directly on the surface of the anchor layer.
  • the total thickness (T1+T2) of the easy-adhesion layer thickness T1 and the anchor layer thickness T2 is 150 nm or more, and the easy-adhesion layer contains organic particles (NP) whose average particle diameter T3 is equal to or greater than the thickness T1 of the easy-adhesion layer.
  • the multilayer film having one each of an easy-adhesion layer, an anchor layer, and a top layer will be mainly described as an example.
  • the present invention is not limited thereto.
  • the multilayer film may have an easy-adhesion layer, an anchor layer, and a top layer provided on both main surfaces of a single-layer base film.
  • the multilayer film has the above-mentioned structure, making it possible to produce a film with good adhesion.
  • adhesion is an index of resistance to peeling between the base film and the top layer.
  • the laminate of the base film and the easy-adhesion layer produced in the middle has good slip properties, so that the laminate is less likely to be scratched even if it is rolled up during production, and can be smoothly unrolled. Therefore, a multilayer film with good adhesion can be easily produced.
  • the total thickness (T1+T2) is preferably 80 nm or more, more preferably 100 nm or more, even more preferably 110 nm or more, even more preferably 150 nm or more, even more preferably 160 nm or more, even more preferably 165 nm or more, and from the viewpoint of minimizing the effect on the optical properties of the multilayer film, it is preferably 800 nm or less, more preferably 700 nm or less, even more preferably 500 nm or less.
  • the thickness of the layers in the multilayer film can be measured using a spectroscopic reflection film thickness measuring device (e.g., the F20 spectroscopic reflection film thickness measuring system manufactured by Filmetrics).
  • a spectroscopic reflection film thickness measuring device e.g., the F20 spectroscopic reflection film thickness measuring system manufactured by Filmetrics.
  • the ratio (T1/T3) of the thickness T1 of the easy-adhesion layer to the average particle diameter T3 of the organic particles (NP) is usually 1/1 or less (i.e., 1 or less), preferably 0.8 or less, more preferably 0.6 or less, and even more preferably 0.46 or less, and may usually be greater than 0, for example, 0.1 or more.
  • T1/T3 is within the above range, both the adhesion of the multilayer film and the surface condition of the multilayer film can be improved.
  • the average particle diameter T3 of the organic particles (NP) is, for example, 100 nm or more, for example, 150 nm or more, and is, for example, 1000 nm or less, for example, 800 nm or less.
  • the average particle diameter T3 of the organic particles (NP) is the weight average particle diameter measured by dynamic light scattering.
  • the base film may be a film containing a thermoplastic resin.
  • the thermoplastic resin that may be contained in the base film may be referred to as a thermoplastic resin (s).
  • the base film may be a film made of only the thermoplastic resin (s).
  • the thermoplastic resin (s) is a thermoplastic resin containing a polymer and further containing an optional component as necessary.
  • a resin having a negative inherent birefringence may be used as the thermoplastic resin (s)
  • a resin having a positive inherent birefringence is preferred from the viewpoint of easily manufacturing a multilayer film as a broadband wavelength film.
  • Resins having positive intrinsic birefringence usually include polymers having positive intrinsic birefringence.
  • polymers having positive intrinsic birefringence include polyolefins such as polyethylene and polypropylene; polyesters such as polyethylene terephthalate and polybutylene terephthalate; polyarylene sulfides such as polyphenylene sulfide; polyvinyl alcohol; polycarbonate; polyarylate; cellulose ester polymers; polyethersulfone; polysulfone; polyarylsulfone; polyvinyl chloride; alicyclic structure-containing polymers such as norbornene-based polymers; rod-shaped liquid crystal polymers, and the like. These polymers may be used alone or in combination of two or more types in any ratio. The polymers may be homopolymers or copolymers.
  • Examples of cycloolefin-based polymers that contain an alicyclic structure include (1) norbornene-based polymers, (2) monocyclic olefin polymers, (3) cyclic conjugated diene polymers, (4) vinyl alicyclic hydrocarbon polymers, and hydrogenated products thereof. Of these, norbornene-based polymers are preferred. Examples of norbornene-based polymers include ring-opening polymers of norbornene monomers, ring-opening copolymers of norbornene monomers and other monomers that can be copolymerized by ring-opening, and hydrogenated products thereof; addition polymers of norbornene monomers, and addition copolymers of norbornene monomers and other monomers that can be copolymerized. Of these, hydrogenated products of ring-opening polymers of norbornene monomers are particularly preferred from the viewpoint of transparency.
  • the alicyclic structure-containing polymer is selected from the polymers disclosed in, for example, JP-A-2002-32
  • the polymer ratio in the thermoplastic resin (s) is preferably 50% to 100% by weight, more preferably 70% to 100% by weight, and particularly preferably 90% to 100% by weight. When the polymer ratio is within the above range, a multilayer film with excellent heat resistance and transparency can be produced.
  • the thermoplastic resin (s) may further contain optional components other than the polymer in combination with the polymer.
  • optional components include colorants such as pigments and dyes; plasticizers; fluorescent whitening agents; dispersants; heat stabilizers; light stabilizers; UV absorbers; antistatic agents; antioxidants; fine particles; surfactants, etc.
  • colorants such as pigments and dyes; plasticizers; fluorescent whitening agents; dispersants; heat stabilizers; light stabilizers; UV absorbers; antistatic agents; antioxidants; fine particles; surfactants, etc.
  • One of these components may be used alone, or two or more may be used in combination in any ratio.
  • the glass transition temperature TgA of the thermoplastic resin (s) is preferably 100°C or higher, more preferably 110°C or higher, particularly preferably 120°C or higher, and is preferably 190°C or lower, more preferably 180°C or lower, particularly preferably 170°C or lower.
  • the glass transition temperature TgA of the thermoplastic resin (s) is equal to or higher than the lower limit of the above range, the durability of the substrate film in a high-temperature environment can be improved.
  • the glass transition temperature TgA of the thermoplastic resin (s) is equal to or lower than the upper limit of the above range, the stretching process can be easily performed.
  • the glass transition temperature can be measured using a differential scanning calorimeter (manufactured by SII Nanotechnology, product name: DSC6220) at a heating rate of 10°C/min according to JIS-K7121.
  • thermoplastic resin (s) preferably does not contain particles.
  • "not containing" particles can also include the case where the resin does not substantially contain particles.
  • the case where the resin does not substantially contain particles means that the thermoplastic resin (s) contains particles, and the increase in haze of the base film compared to a state where the resin does not contain any particles is within a range of 0.05% or less.
  • the thickness of the base film is preferably 30 ⁇ m or more, more preferably 35 ⁇ m or more, particularly preferably 40 ⁇ m or more, and preferably 60 ⁇ m or less, more preferably 55 ⁇ m or less, particularly preferably 50 ⁇ m or less.
  • the output of the corona treatment is preferably set to a condition that minimizes damage to the surface to be treated, specifically, it is preferably 0.02 kW or more, more preferably 0.04 kW or more, and is preferably 5 kW or less, more preferably 2 kW or less.
  • the easy-adhesion layer contains organic particles (NP), and preferably contains a polymer in addition to the organic particles (NP).
  • the easy-adhesion layer is more preferably a cured product of the easy-adhesion layer material.
  • the easy-adhesion layer is provided to improve the slipperiness of a film produced intermediately in the production of a multilayer film.
  • the material preferably comprises a polymer (P1) and a cross-linking agent (1).
  • the (meth)acrylic monomer unit is a structural unit having a structure that can be obtained by polymerizing a (meth)acrylic monomer.
  • the (meth)acrylic monomer means (meth)acrylic acid and a derivative of (meth)acrylic acid.
  • Examples of the derivative of (meth)acrylic acid include (meth)acrylic acid esters, (meth)acrylamide, and (meth)acrylonitrile, and (meth)acrylic acid esters are preferred.
  • Examples of (meth)acrylic acid esters include alkyl (meth)acrylates, and the alkyl group in the alkyl (meth)acrylate may or may not have a substituent such as a hydroxyl group or a halogen atom.
  • the (meth)acrylic polymer may contain any monomer unit in addition to the (meth)acrylic monomer unit.
  • the (meth)acrylic polymer is preferably a crosslinked polymer containing a crosslinkable monomer unit.
  • the crosslinkable monomer unit is a unit that can be obtained by polymerizing a crosslinkable monomer.
  • crosslinkable monomer examples include polyfunctional monomers containing two or more polymerizable groups per molecule, specifically, divinylbenzene, ethylene glycol di(meth)acrylate, hexanediol di(meth)acrylate, pentaerythritol triacrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tetraacrylate, diallyl phthalate, and triallyl cyanurate.
  • the crosslinkable monomer may be used alone or in combination of two or more types at any ratio.
  • particles containing (meth)acrylic acid ester units are preferred, and particles of a polymethyl methacrylate-based crosslinked polymer containing methyl methacrylate units and crosslinkable monomer units are more preferred.
  • organic particles may be used.
  • examples of commercially available organic particles include Nippon Shokubai's "Eposter (registered trademark) MX Series” (particles of polymethyl methacrylate-based cross-linked polymer), Soken Chemical Industry's “Chemisnow MP Series” (acrylic polymer particles), Soken Chemical Industry's “Chemisnow MX Series” (styrene-acrylic resin particles), and Sekisui Chemical Industry's "Techpolymer.”
  • the average particle diameter of the organic particles is usually equal to or larger than the thickness T1 of the easy-adhesion layer, preferably less than 450 nm, more preferably 400 nm or less, and even more preferably 350 nm or less.
  • the average particle diameter of the organic particles is within the above range, the organic particles are less likely to fall off from the easy-adhesion layer.
  • the slipperiness of the laminate of the substrate film and the easy-adhesion layer produced in the middle is improved.
  • the content of the organic particles in the easy-adhesion layer is usually the same as the weight ratio of the organic particles contained in the easy-adhesion material when the total amount of solids in the easy-adhesion layer material for forming the easy-adhesion layer is 100% by weight.
  • urethane resin a resin containing polyurethane or its crosslinked product as the polymer (P1) can be used.
  • polyurethane include polyurethanes derived from various polyols and polyisocyanates.
  • polyols include any one of aliphatic polyester polyols, polyether polyols, polycarbonate polyols, and polyethylene terephthalate polyols obtained by the reaction of a polyol compound with a polybasic acid; and mixtures thereof.
  • the polyol compound include ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, glycerin, trimethylolpropane, and the like.
  • polybasic acid examples include polybasic carboxylic acids such as polybasic carboxylic acids including dicarboxylic acids and tricarboxylic acids, or anhydrides thereof.
  • dicarboxylic acids include adipic acid, succinic acid, sebacic acid, glutaric acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, and the like.
  • tricarboxylic acids include trimellitic acid, and the like.
  • polyether polyol examples include poly(oxypropylene ether) polyol and poly(oxyethylene-propylene ether) polyol.
  • the unreacted hydroxyl groups remaining can be used as polar groups capable of crosslinking with the functional groups in the crosslinking agent.
  • a polycarbonate-based polyurethane derived from a polycarbonate-based polyol and polyisocyanate and containing a carbonate structure in its skeleton is preferred.
  • JP 2016-182568 A the description in JP 2016-182568 A can be referred to, for example.
  • water-based urethane resins are compositions containing polyurethane and water, and usually polyurethane and optional components contained as necessary are dispersed in water.
  • water-based urethane resins examples include the "ADEKA BONTITOR” series manufactured by ADEKA Corporation, the “OLESTAR” series manufactured by Mitsui Chemicals, Inc., the “BONDIC” series manufactured by DIC Corporation, the “HYDRAN (WLS201, WLS202, etc.)” series manufactured by Bayer, the "POISE” series manufactured by Kao Corporation, the "SANPRENE” series manufactured by Sanyo Chemical Industries, Ltd., the "SUPERFLEX” series manufactured by Daiichi Kogyo Seiyaku Co., Ltd., the "NEOREZ” series manufactured by Kusumoto Chemicals, Inc., and the "SANCURE” series manufactured by Lubrizol Corporation.
  • olefin resin a resin containing an acid-modified polyolefin or its crosslinked product having an unsaturated carboxylic acid component content of 0.1% by weight to 10% by weight as the polymer (P1) can be used.
  • Preferred examples of the olefin component that is the main component of the acid-modified polyolefin include alkenes having 2 to 6 carbon atoms, such as ethylene, propylene, isobutylene, 2-butene, 1-butene, 1-pentene, and 1-hexene, and mixtures thereof.
  • alkenes having 2 to 4 carbon atoms such as ethylene, propylene, isobutylene, and 1-butene
  • examples of the unsaturated carboxylic acid component that is the modified component of the acid-modified polyolefin include acrylic acid, methacrylic acid, maleic acid (anhydride), itaconic acid (anhydride), fumaric acid, crotonic acid, half esters of unsaturated dicarboxylic acids, and half amides.
  • acrylic acid, methacrylic acid, and maleic acid are preferred, and acrylic acid and maleic acid (anhydride) are particularly preferred, since they can increase the adhesion of the layer formed of the resin (hereinafter also referred to as the resin layer) and suppress cracking.
  • the unsaturated carboxylic acid component is usually copolymerized in the acid-modified polyolefin, and the form is not particularly limited. Examples of the copolymerization state include random copolymerization, block copolymerization, and graft copolymerization (graft modification).
  • the description in JP-A-2014-240174 can be referred to, for example.
  • aqueous dispersions include the "Arrowbase (Arrowbase SA-1200, Arrowbase SB-1200, Arrowbase SE-1200, Arrowbase SB-1010)" series (manufactured by Unitika Ltd.).
  • the polyester resin a resin containing a polyester or its crosslinked product obtained by the reaction of the polyol compound with the polybasic acid can be used as the polymer (P1).
  • the polyester for example, after the reaction between the polyol compound and the polybasic acid is completed, the unreacted hydroxyl group and carboxyl group remaining can be used as a polar group capable of crosslinking with a crosslinking agent.
  • the polyester may also be a copolymer of the polyol compound and the polybasic acid with a copolymer component having a polar group such as a hydroxyl group or a carboxyl group.
  • the polyester resin preferably further contains an acrylic polymer in combination with the polyester or its crosslinked product in order to improve the adhesion of the resin layer.
  • the description in JP 2015-024511 A may be referred to.
  • polyester commercially available products may be used.
  • examples of commercially available water-soluble or water-dispersible polyester products include the "Nichigo Polyester (Nichigo Polyester W-0030, Nichigo Polyester W-0005S30WO, Nichigo Polyester WR-961, etc.)” series (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) and the "PES Resin A (PES Resin A-210, PES Resin A-520, PES Resin A-684G, PES Resin A-695GE, etc.)” series (manufactured by Takamatsu Oil Co., Ltd.).
  • any epoxy resin can be used, such as a one-component curing type epoxy resin or a two-component curing type epoxy resin.
  • those containing a water-soluble epoxy polymer as the polymer (P1) are preferable.
  • a preferable example of a water-soluble epoxy polymer is polyamide epoxy polymer.
  • This polyamide epoxy polymer is obtained by reacting epichlorohydrin with polyamide polyamine obtained by reacting polyalkylene polyamine such as diethylenetriamine or triethylenetetramine with dicarboxylic acid such as adipic acid.
  • Commercially available products of such polyamide epoxy polymers include "Sumirez Resin 650 (30)" and “Sumirez Resin 675" manufactured by Sumika Chemtech Co., Ltd.
  • This polyvinyl alcohol includes not only partially saponified polyvinyl alcohol and fully saponified polyvinyl alcohol, but also modified polyvinyl alcohols such as carboxyl group-modified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, methylol group-modified polyvinyl alcohol, and amino group-modified polyvinyl alcohol.
  • modified polyvinyl alcohols such as carboxyl group-modified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, methylol group-modified polyvinyl alcohol, and amino group-modified polyvinyl alcohol.
  • An example of a commercially available polyvinyl alcohol is "KL-318," an anionic group-containing polyvinyl alcohol manufactured by Kuraray Co., Ltd.
  • the (meth)acrylic resin a resin containing a (meth)acrylic polymer or a crosslinked product thereof can be used as the polymer (P1).
  • examples of the (meth)acrylic polymer include a homopolymer of a (meth)acrylic monomer, a copolymer of two or more types of (meth)acrylic monomers, and a copolymer of one or more types of (meth)acrylic monomers with other monomers.
  • examples of the (meth)acrylic monomer include acrylic acid, acrylic acid esters such as alkyl acrylates, acrylamide, acrylonitrile, methacrylic acid, methacrylic acid esters such as alkyl methacrylates, methacrylamide, and methacrylonitrile.
  • the polymer (P1) a polymer having a (meth)acrylic acid ester unit is preferable, and a homopolymer or copolymer of an acrylic monomer selected from the group consisting of an acrylic acid ester and a methacrylic acid ester is more preferable.
  • Particularly preferable examples include a homopolymer or copolymer of an acrylic monomer selected from the group consisting of an acrylic acid ester and a methacrylic acid ester having an alkyl group having 1 to 6 carbon atoms.
  • the acrylic polymer is preferably a copolymer of a copolymerization component having a polar group such as a hydroxyl group or a carboxyl group in combination with the acrylic monomer so as to be capable of reacting (crosslinking reaction) with the functional group of the crosslinking agent.
  • a copolymerization component having a polar group such as a hydroxyl group or a carboxyl group in combination with the acrylic monomer so as to be capable of reacting (crosslinking reaction) with the functional group of the crosslinking agent.
  • a polar group such as a hydroxyl group or a carboxyl group
  • the weight proportion of the (meth)acrylic acid ester units in the polymer (P1) is preferably 1% by weight or more, more preferably 5% by weight or more, and even more preferably 10% by weight or more, and is usually 100% by weight or less, assuming that the total of the monomer units contained in the polymer (P1) is 100% by weight.
  • the polymer (P1) contained in the easy-adhesion layer material is preferably a copolymer of an alkyl ester of methacrylic acid and an alkyl ester of acrylic acid.
  • the number of carbon atoms in the alkyl group constituting the alkyl ester is preferably 1 to 6, and particularly preferably 1 to 4.
  • the polymer (P1) is a copolymer of methyl methacrylate and butyl acrylate.
  • the polymer (P1) constituting the easy-adhesion layer material may be one type, or two or more types. Therefore, the easy-adhesion layer material may be a composite resin containing two or more types of the above-mentioned polyurethane, polyolefin, polyester, epoxy polymer, and (meth)acrylic polymer in combination. For example, it may be a resin containing a combination of polyurethane and acid-modified polyolefin, or a resin containing a combination of polyester and acrylic polymer.
  • the proportion of polymer (P1) in the solid content (total amount of components other than the solvent) of the easy-adhesion layer material is preferably 50% by weight to 99% by weight, more preferably 70% by weight to 99% by weight, and particularly preferably 90% by weight to 97% by weight.
  • the proportion of polymer (P1) is within the above range, the resulting easy-adhesion layer can exhibit the desired adhesion.
  • the easy-adhesion layer which is a cured product of the easy-adhesion layer material, can be a layer containing a polymer having a crosslinked structure.
  • the crosslinking agent (1) a compound having two or more functional groups in the molecule capable of reacting with a functional group such as a polar group contained in the polymer to form a bond, a polymer crosslinking agent in which a monomer composition containing the compound is polymerized to form a polymer having a functional group capable of forming a bond, or a mixture thereof can be used.
  • crosslinking agent compound examples include an epoxy compound, a carbodiimide compound, an oxazoline compound, an isocyanate compound, and the like.
  • the crosslinking agent compound may be used alone or in combination of two or more types in any ratio.
  • epoxy compound a multifunctional epoxy compound having two or more epoxy groups in the molecule can be used. This allows the crosslinking reaction to proceed, effectively improving the mechanical strength of the resin layer.
  • epoxy compounds those that are soluble in water or can be dispersed in water to form an emulsion are preferred from the viewpoint of ease of use.
  • examples of epoxy compounds include diepoxy compounds obtained by etherifying 1 mole of glycols such as ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, 1,6-hexylene glycol, and neopentyl glycol with 2 moles of epichlorohydrin; polyepoxy compounds obtained by etherifying 1 mole of polyhydric alcohols such as glycerin, polyglycerin, trimethylolpropane, pentaerythritol, and sorbitol with 2 moles or more of epichlorohydrin; diepoxy compounds obtained by esterifying 1 mole of dicarboxylic acid such as phthalic acid, terephthalic acid, oxalic acid, and adipic acid with 2
  • preferred epoxy compounds include 1,4-bis(2',3'-epoxypropyloxy)butane, 1,3,5-triglycidyl isocyanurate, 1,3-diglycidyl-5-( ⁇ -acetoxy- ⁇ -oxypropyl)isocyanurate, sorbitol polyglycidyl ethers, polyglycerol polyglycidyl ethers, pentaerythritol polyglycidyl ethers, diglycerol polyglycidyl ethers, glycerol polyglycidyl ethers, and trimethylolpropane polyglycidyl ethers.
  • Specific examples of commercially available products include the "Denacol (Denacol EX-521, EX-614B, etc.)" series manufactured by Nagase ChemteX Corporation.
  • an addition-polymerizable oxazoline compound can be used as the oxazoline compound.
  • Specific examples include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, and 2-isopropenyl-5-ethyl-2-oxazoline. These compounds may be used alone or in combination of two or more at any ratio. Among these, 2-isopropenyl-2-oxazoline is preferred because it is easily available industrially.
  • a crosslinking agent (1-o) that is a polymer of an addition-polymerizable oxazoline compound and an arbitrary unsaturated monomer is particularly preferred.
  • the arbitrary unsaturated monomer other than the oxazoline compound that constitutes the crosslinking agent (1-o) any monomer that is copolymerizable with the addition-polymerizable oxazoline and does not react with the oxazoline group can be used.
  • Such an arbitrary unsaturated monomer can be arbitrarily selected from the monomers described above.
  • a specific example of a preferred unsaturated monomer is a methacrylic acid ester such as methyl methacrylate.
  • the crosslinking agent (1-o) a copolymer of 2-isopropenyl-2-oxazoline and a methacrylic acid ester is particularly preferred in terms of achieving the desired effects such as good adhesion.
  • the amount of addition-polymerizable oxazoline used in the production of the crosslinking agent (1-o) is preferably 5 parts by weight or more per 100 parts by weight of the total monomer components used in the production of the oxazoline compound.
  • Crossing agents (1-o) that are commercially available can be used.
  • water-soluble crosslinking agents (1-o) include Epocross WS-500 and WS-700 manufactured by Nippon Shokubai Co., Ltd.
  • emulsion-type crosslinking agents (1-o) include Epocross K-2010, K-2020, and K-2030 manufactured by Nippon Shokubai Co., Ltd.
  • Crosslinking agent (1-o) and other crosslinking agents (1) may be used alone or in combination of two or more in any ratio.
  • the ratio of the crosslinking agent (1) to the polymer (P1) in the easy-adhesion layer can be adjusted appropriately to a range in which the desired adhesion and other effects are achieved.
  • the ratio of the crosslinking agent (1) to a total of 100 parts by weight of the polymer (P1) and the crosslinking agent (1) is preferably 1 part by weight or more, more preferably 3 parts by weight or more, while it is preferably 30 parts by weight or less, more preferably 20 parts by weight or less.
  • the easy-adhesion layer material may contain a solvent. By containing a solvent, the easy-adhesion layer material can be made into a liquid composition, and the operation of forming the easy-adhesion layer, such as coating, can be facilitated.
  • a solvent water, an organic solvent, or a mixture thereof can be appropriately selected.
  • organic solvents examples include methyl acetate, ethyl acetate, acetone, methyl ethyl ketone, 3-methyl-2-butanone, methyl isopropyl ketone, methyl isobutyl ketone, tetrahydrofuran, cyclopentyl methyl ether, acetylacetone, cyclohexanone, 2-methylcyclohexanone, 1,3-dioxolane, 1,4-dioxane, 2-pentanone, and N,N-dimethylformamide.
  • the solvent may be used alone or in combination of two or more kinds in any ratio. Water can be preferably used as the solvent because of its good volatility and high ability to dissolve other components.
  • the proportion of the solvent contained in the easy-adhesion layer material can be adjusted as appropriate to obtain physical properties suitable for the operation of forming the easy-adhesion layer, such as coating. Specifically, the proportion can be adjusted so that the solids concentration (proportion of components other than the solvent, including organic particles (NP)) is preferably 1% by weight to 20% by weight, more preferably 2% by weight to 10% by weight.
  • the solids concentration proportion of components other than the solvent, including organic particles (NP)
  • the easy-adhesion layer material may further include any optional components, such as a curing accelerator, a curing assistant, particles other than organic particles (NPs), a heat stabilizer, a weather stabilizer, a leveling agent, a surfactant, an antioxidant, an antistatic agent, a slip agent, an antiblocking agent, an antifogging agent, a lubricant, a dye, a pigment, a natural oil, a synthetic oil, and a wax.
  • a curing accelerator such as a curing assistant, particles other than organic particles (NPs), a heat stabilizer, a weather stabilizer, a leveling agent, a surfactant, an antioxidant, an antistatic agent, a slip agent, an antiblocking agent, an antifogging agent, a lubricant, a dye, a pigment, a natural oil, a synthetic oil, and a wax.
  • NPs organic particles
  • the anchor layer is preferably a cured product of the anchor layer material.
  • the anchor layer is provided to enhance adhesion between the base film and the top layer.
  • the anchor layer material includes a polymer (P2) and a crosslinking agent (2).
  • Anchor layer material polymer (P2)
  • various resins including polymers can be used.
  • the resin include the same examples as those of the resin that can be contained in the easy-adhesion layer material.
  • the polymer (P2) contained in the anchor layer material is preferably a polymer having a (meth)acrylic acid ester unit.
  • the polymer (P2) is preferably a polymer having a (meth)acrylic acid ester unit, and more preferably a homopolymer or copolymer of an acrylic monomer selected from the group consisting of acrylic acid esters and methacrylic acid esters.
  • Particularly preferred examples include homopolymers and copolymers of acrylic monomers selected from the group consisting of acrylic acid esters and methacrylic acid esters having an alkyl group having 1 to 6 carbon atoms.
  • the acrylic polymer is preferably a copolymer of a copolymerization component having a polar group such as a hydroxyl group or a carboxyl group in combination with the acrylic monomer so as to be capable of reacting (crosslinking reaction) with the functional group of the crosslinking agent.
  • the weight proportion of the (meth)acrylic acid ester units in the polymer (P2) may be in the same range as the weight proportion of the (meth)acrylic acid ester units in the polymer (P1) when the polymer (P1) has (meth)acrylic acid ester units.
  • the polymer (P2) contained in the anchor layer material is preferably a copolymer of an alkyl ester of methacrylic acid and an alkyl ester of acrylic acid.
  • the number of carbon atoms in the alkyl group constituting the alkyl ester is preferably 1 to 6, and particularly preferably 1 to 4.
  • the polymer (P2) is a copolymer of methyl methacrylate and butyl acrylate.
  • the proportion of polymer (P2) in the solid content (total amount of components other than the solvent) of the anchor layer material is preferably 50% by weight to 99% by weight, more preferably 70% by weight to 99% by weight, and particularly preferably 90% by weight to 99% by weight.
  • the proportion of polymer (P2) is within the above range, the resulting anchor layer can exhibit the desired adhesion.
  • the anchor layer which is a cured product of the anchor layer material, can be a layer containing a polymer having a crosslinked structure.
  • the crosslinking agent (2) include the same examples as the examples of the crosslinking agent (1) that can be included in the easy-adhesion layer material.
  • the ratio of the crosslinking agent (2) to the polymer (P2) in the anchor layer can be adjusted appropriately to a range in which the desired adhesion and other effects are achieved. Specifically, it can be in the same range as the ratio of the crosslinking agent (1) to the polymer (P1) in the easy-adhesion layer.
  • the anchor layer material may contain a solvent.
  • a solvent By containing a solvent, the anchor layer material can be made into a liquid composition, and the operation of forming the anchor layer, such as coating, can be facilitated.
  • the solvent include the same examples as those of the solvent that the easy-adhesion layer material may contain.
  • the solvent may be used alone or in combination of two or more types in any ratio. Water is preferably used as the solvent because of its good volatility and high ability to dissolve other components.
  • the proportion of the solvent in the anchor layer material can be adjusted as appropriate to obtain properties suitable for the operation of forming the anchor layer, such as coating. Specifically, the proportion can be adjusted so that the solids concentration (proportion of components other than the solvent) is preferably 1% by weight to 20% by weight, and more preferably 2% by weight to 15% by weight.
  • the anchor layer material may further contain optional components.
  • optional components include the same examples as the optional components that may be contained in the easy-adhesion layer material.
  • One type of optional component may be used alone, or two or more types may be used in combination in any ratio.
  • the polymer (P2) that can be contained in the anchor layer material and the polymer (P1) that can be contained in the easy-adhesion layer material preferably have a common monomer unit. It is more preferable that the anchor layer material contains a polymer containing a (meth)acrylic acid ester unit as the polymer (P2), and the easy-adhesion layer material contains a polymer containing a (meth)acrylic acid ester unit as the polymer (P1), and that the polymer (P1) and the polymer (P2) have a common (meth)acrylic acid ester unit.
  • Polymer (P1) and Polymer (P2) having common (meth)acrylic acid ester units means that both Polymer (P1) and Polymer (P2) have common acrylic acid ester units and/or common methacrylic acid ester units.
  • common (meth)acrylic acid ester units it is preferable for the "common (meth)acrylic acid ester units” to have methacrylic acid ester units, and it is even more preferable for them to have methyl methacrylate units.
  • both polymer (P1) and polymer (P2) are preferably polymers having methyl methacrylate units and butyl acrylate units, and more preferably copolymers of methyl methacrylate and butyl acrylate.
  • crosslinking agent (2) that can be contained in the anchor layer material and the crosslinking agent (1) that can be contained in the easy-adhesive material are preferably the same crosslinking agent. More specifically, it is more preferable that both the crosslinking agent (1) and the crosslinking agent (2) are copolymers of methyl methacrylate and 2-isopropenyl oxazoline.
  • the top layer is preferably a cured product of the top layer material.
  • the top layer is preferably a coated layer formed by coating the top layer material.
  • the top layer material is preferably a material containing a polymer (P3).
  • top Layer Material Polymer (P3))
  • P3 polymer having positive intrinsic birefringence
  • a polymer having negative intrinsic birefringence is preferred.
  • polymers having negative intrinsic birefringence include homopolymers of styrene or styrene derivatives, and styrene-based polymers including copolymers of styrene or styrene derivatives with any monomer (e.g., polystyrene, poly(2-vinylnaphthalene)); polyacrylonitrile polymers; polymethyl methacrylate polymers; multicomponent copolymers thereof; and cellulose compounds such as cellulose ester polymers. These polymers may be used alone or in combination of two or more types in any ratio.
  • polymers having styrene-based monomer units or cellulose ester polymers are preferred, and polymers having styrene-based monomer units are more preferred.
  • styrene-based monomer refers to styrene monomers, styrene derivative monomers, and combinations thereof.
  • optional monomers that copolymerize with styrene or styrene derivatives include acrylonitrile, maleic anhydride, methyl methacrylate, and butadiene. These polymers may be used alone or in combination of two or more in any ratio.
  • styrene derivatives include derivatives having substituents at one or more substitution positions selected from the benzene ring, ⁇ -position, or ⁇ -position of styrene, and hydrogenated versions of these.
  • substituents include halogen atoms, alkyl groups, alkenyl groups, aromatic groups, alkoxy groups, and alkoxycarbonyl groups. When the substituents are carbon-containing groups, the number of carbon atoms per substituent may be 1 to 6.
  • Styrene derivatives also include derivatives having a structure in which substituents at multiple substitution positions on the benzene ring are bonded to form a ring (e.g., vinylnaphthalene).
  • styrene monomers include styrene, halogenated styrene, halogenated alkylstyrene, alkylstyrene, alkenylstyrene, alkoxystyrene, alkoxycarbonylstyrene, and hydrogenated versions of these.
  • halogenated styrenes examples include chlorostyrene, bromostyrene, and fluorostyrene.
  • An example of a halogenated alkylstyrene is chloromethylstyrene.
  • alkylstyrenes examples include methylstyrene, ethylstyrene, isopropylstyrene, t-butylstyrene, and 2,4-dimethylstyrene.
  • alkenylstyrenes examples include vinylstyrene.
  • alkoxystyrenes examples include methoxystyrene and ethoxystyrene.
  • alkoxycarbonylstyrenes examples include vinyl benzoate.
  • styrene monomers include phenylstyrene and vinylnaphthalene.
  • a cellulose ester polymer with negative intrinsic birefringence is a cellulose ester polymer in which an appropriate aryl group has been introduced into cellulose by acylation.
  • a particularly preferred example of the polymer (P3) constituting the top layer material is a copolymer of styrene or a styrene derivative and maleic anhydride.
  • a copolymer of styrene or a styrene derivative and maleic anhydride is particularly preferred from the viewpoint of high heat resistance.
  • the amount of maleic anhydride units is preferably 5 parts by weight or more, more preferably 10 parts by weight or more, particularly preferably 15 parts by weight or more, and preferably 30 parts by weight or less, more preferably 28 parts by weight or less, particularly preferably 26 parts by weight or less, per 100 parts by weight of the styrene-based polymer.
  • a maleic anhydride unit refers to a structural unit having a structure formed by polymerizing maleic anhydride.
  • the proportion of polymer (P3) in the solid content (total amount of components other than the solvent) of the top layer material is preferably 50% by weight to 100% by weight, more preferably 70% by weight to 100% by weight, and particularly preferably 90% by weight to 100% by weight.
  • the top layer can exhibit appropriate optical properties.
  • the top layer material may contain a solvent.
  • the top layer material By containing a solvent, the top layer material can be a liquid composition, and the operation of forming the top layer, such as coating, can be facilitated.
  • the solvent include the same examples as those of the solvent that can be contained in the easy-adhesion layer material.
  • the solvent may be used alone or in combination of two or more types in any ratio. Ketones such as methyl ethyl ketone, methyl isobutyl ketone, or mixtures thereof can be preferably used as the solvent because of their good volatility and high ability to dissolve other components.
  • the proportion of solvent in the top layer material can be adjusted as appropriate to obtain physical properties suitable for the operation of forming the top layer, such as coating. Specifically, the proportion can be adjusted so that the solids concentration (proportion of components other than the solvent) is preferably 5% to 25% by weight, more preferably 10% to 20% by weight.
  • the top layer material may further contain an optional additive (t).
  • the additive (t) is a separate component that is usually contained in a smaller weight ratio than the polymer (P3), which is the main component.
  • the additive (t) is preferably a substance that is compatible with the polymer (P3). Specifically, when the additive (t) is contained, it is preferable to appropriately select the type of additive (t) so as to satisfy the haze requirements of the resulting multilayer film.
  • Additive (t) can perform functions such as adjusting the degree of optical anisotropy of the top layer to a desired range.
  • Additive (t) can perform functions such as adjusting the degree of optical anisotropy of the top layer to a desired range.
  • the thickness of the top layer suitable for obtaining the desired optical properties of the final stretched multilayer film is excessively thin, the molding precision decreases and the surface unevenness of the top layer may become large.
  • additive (t) having positive intrinsic birefringence to the top layer material in combination with polymer (P3) having negative intrinsic birefringence, it is possible to improve the surface unevenness of the top layer.
  • additives (t) include polymers such as (meth)acrylic polymers, styrene polymers, (meth)acrylic-styrene copolymers, polyesters, polycarbonates, and olefin polymers. These polymers may be used alone or in combination of two or more in any ratio, or may be copolymers of each resin. In particular, (meth)acrylic polymers, styrene polymers, and (meth)acrylic-styrene copolymers are preferred because they are highly likely to be compatible with the polymer (P3) having a negative intrinsic birefringence value.
  • P3 polymer having a negative intrinsic birefringence value
  • a particularly preferred example of additive (t) from the viewpoint of compatibility with the preferred polymer (P3), and of satisfactorily satisfying the above-mentioned additive properties and other requirements of the present invention is a copolymer containing (meth)acrylic acid ester units and styrene-based monomer units (for example, product name "TX-100S", manufactured by Denka Co., Ltd., a copolymer of methyl methacrylate and styrene).
  • the ratio of additive (t) to polymer (P3) can be adjusted appropriately to a range in which the desired optical effects and other effects are achieved, such as adjusting the degree of optical anisotropy of the top layer to a desired range.
  • the ratio of additive (t) to 100 parts by weight of polymer (P3) is preferably more than 0 parts by weight, preferably 5 parts by weight or more, and preferably 75 parts by weight or less, more preferably 70 parts by weight or less, even more preferably 50 parts by weight or less, and even more preferably 25 parts by weight or less.
  • top layer material other ingredients
  • the top layer material may further include optional components.
  • optional components include the same optional components as those included in the thermoplastic resin (s).
  • the optional components may be used alone or in combination of two or more in any ratio.
  • the easy-adhesion layer is usually a cured product of the easy-adhesion layer material described above
  • the anchor layer is usually a cured product of the anchor layer material described above
  • the top layer is usually a cured product of the top layer material described above.
  • the method of forming the easy-adhesion layer, anchor layer, and top layer from the easy-adhesion layer material, anchor layer material, and top layer material, respectively, is not particularly limited, and any known method can be appropriately selected and used.
  • the easy-adhesion layer can be formed by applying the easy-adhesion layer material to the surface of the base film to form a coating film of the easy-adhesion layer material and drying the coating film.
  • the anchor layer can be formed by applying the anchor layer material to the surface of the easy-adhesion layer to form a coating film of the anchor layer material and drying the coating film.
  • the top layer can be formed by applying the top layer material to the surface of the anchor layer to form a coating film of the top layer material and drying the coating film.
  • the easy-adhesion layer material, anchor layer material, and top layer material may each contain a solvent. When forming the easy-adhesion layer, anchor layer, and top layer, these solvents may volatilize and disappear in part or in whole from the layers.
  • the easy-adhesion layer material and anchor layer material may contain reactive materials such as crosslinking agents. When forming the easy-adhesion layer and anchor layer, these reactive materials may react and become elements that form part of the structure of polymer molecules, such as crosslinking.
  • the multilayer film of this embodiment can be manufactured by any method.
  • the multilayer film can be manufactured by a manufacturing method including the following steps (1), (2-1), (2-2), (3), (4), (5-1), (5-2), (6-1), (6-2), and (7) in this order.
  • the manufacturing method for the multilayer film may include any steps in addition to the steps below.
  • Step (1) A step of preparing a long base film.
  • Step (2-1) A step of applying a liquid adhesive layer material onto the base film to form a coating film of the adhesive layer material.
  • Step (2-2) A step of drying the coating film of the easy-adhesion layer material to form an easy-adhesion layer and obtain a multilayer body (I) having the base film and the easy-adhesion layer.
  • Step (3) A step of stretching the multi-layered product (I) to obtain a multi-layered product (II).
  • Step (5-1) A step of unwinding the wound multilayer material (II) and applying a liquid anchor layer material onto the easy-adhesion layer of the multilayer material (II) to form a coating film of the anchor layer material.
  • Step (5-2) A step of drying the coating film of the anchor layer material to form an anchor layer, thereby obtaining a multilayer body (III) having the base film, the easy-adhesion layer, and the anchor layer in this order.
  • Step (6-1) A step of applying a liquid top layer material onto the anchor layer of the multilayer structure (III) to form a coating film of the top layer material.
  • a base film is prepared.
  • the base film is usually formed by molding a thermoplastic resin (s).
  • the base film is usually formed as a film. From the viewpoint of efficient production of the multilayer film, it is preferable that the base film is formed as a long film.
  • the base film is cut along its longitudinal direction. The substrate can then be transported onto a transport line, and subsequent steps can be carried out continuously downstream of the transport line.
  • the method for forming the substrate film is not particularly limited.
  • methods for forming the substrate film include melt molding and solution casting. More specific examples of melt molding include extrusion molding, press molding, inflation molding, injection molding, blow molding, and stretch molding. Among these methods, from the viewpoint of obtaining a substrate film with excellent mechanical strength and surface precision, extrusion molding, inflation molding, and press molding are preferred, and among these, extrusion molding is particularly preferred from the viewpoint of being able to efficiently and easily produce a substrate film.
  • step (2-1) In the step (2-1), a liquid adhesive layer material is applied onto the base film to form a coating film of the adhesive layer material.
  • liquid adhesive layer materials examples include curtain coating, extrusion coating, roll coating, spin coating, dip coating, bar coating, spray coating, slide coating, print coating, gravure coating, die coating, and gap coating.
  • the coating thickness of the easy-adhesion layer material can be adjusted so that the easy-adhesion layer has the desired thickness T1 in the multilayer film produced.
  • step (2-2) the coating film of the easy-adhesion layer material is dried to form an easy-adhesion layer, and a multilayer body (I) including the base film and the easy-adhesion layer is obtained.
  • the coating film of the easy-adhesion layer material can be dried by a drying method such as natural drying, heat drying, reduced pressure drying, reduced pressure heat drying, etc.
  • a treatment for promoting crosslinking may be optionally performed on the coating film of the easy-adhesion layer material.
  • Such a treatment can promote the crosslinking reaction of the crosslinking agent (1) and improve the mechanical strength and solvent resistance of the easy-adhesion layer.
  • crosslinking treatments include heating treatment and irradiation with active energy rays such as ultraviolet rays.
  • Step (3) In the step (3), the multi-layered product (I) is stretched to obtain a multi-layered product (II).
  • the angle that the stretching direction makes with the width direction of the base film is preferably 35° or more, more preferably 37° or more, even more preferably 40° or more, particularly preferably 42° or more, and is preferably 55° or less, more preferably 53° or less, even more preferably 50° or less, particularly preferably 48° or less.
  • the stretching ratio in step (3) is preferably 1.1 times or more, more preferably 1.2 times or more, and is preferably 2.5 times or less, more preferably 2.0 times or less.
  • the stretching ratio is equal to or greater than the lower limit of the range, the refractive index in the stretching direction can be increased.
  • the stretching ratio is equal to or less than the upper limit of the range, the direction of the slow axis of the stretched substrate film can be easily controlled.
  • the stretching temperature in step (3) is preferably TgA or higher, more preferably (TgA+2)°C or higher, particularly preferably (TgA+5)°C or higher, and is preferably (TgA+40)°C or lower, more preferably (TgA+35)°C or lower, particularly preferably (TgA+30)°C or lower.
  • TgA represents the glass transition temperature of the thermoplastic resin (s).
  • the direction of the slow axis of the laminate (II) is preferably in an oblique direction that is neither parallel nor perpendicular to the width direction of the laminate (II).
  • the orientation angle of the laminate (II) is preferably 25° or more, more preferably 30° or more, even more preferably 35° or more, and is preferably less than 55°, more preferably less than 50°, even more preferably less than 48°.
  • the optical properties such as retardation of the multilayer material (II) can be set according to the optical properties desired to be expressed in the multilayer film.
  • the in-plane retardation Re of the multilayer material (II) is preferably 180 nm or more, more preferably 190 nm or more, particularly preferably 200 nm or more, and is preferably 250 nm or less, more preferably 240 nm or less, particularly preferably 230 nm or less.
  • the thickness of the multilayer material (II) can be set arbitrarily within the range in which the desired multilayer film can be obtained.
  • the specific thickness is preferably 30 ⁇ m or more, more preferably 35 ⁇ m or more, particularly preferably 40 ⁇ m or more, and is preferably 80 ⁇ m or less, more preferably 70 ⁇ m or less, particularly preferably 60 ⁇ m or less.
  • step (4) the laminate (II) is wound up.
  • a base film and organic particles (NP) provided directly on one surface of the base film are A multi-layered product (II) having an easy-adhesion layer which is a cured product of an easy-adhesion layer material containing the organic particles (NP) can be obtained. Therefore, even when the multi-layered material (II) is wound up, the wound multi-layered material (II) is not scratched due to friction between the layers of the multi-layered material (II). Furthermore, in the step (5-1) described below, the multi-layered product (II) can be smoothly unwound.
  • the coefficient of dynamic friction between the base film and the easy-adhesion layer of the multilayered product (II) is preferably 0.8 or less, more preferably 0.75 or less, since this can more effectively reduce defects.
  • the coefficient of dynamic friction between the base film and the easy-adhesion layer can be measured by the following method.
  • step (5-1) the wound multilayered product (II) is unwound, and a liquid anchor layer material is applied onto the adhesive layer of the multilayered product (II), and the anchor layer A coating film of the material is formed.
  • the coating method of the liquid anchor layer material include the same examples as those given as examples of the coating method of the liquid easy-adhesion layer material in step (2-1). .
  • the coating thickness of the anchor layer material can be adjusted so that the anchor layer has the desired thickness T2 in the multilayer film produced.
  • step (5-2) the coating film of the anchor layer material is dried to form an anchor layer, and a multilayer body (III) having the base film, the easy-adhesion layer, and the anchor layer in this order is obtained. obtain.
  • the method for drying the coating film of the anchor layer material include the same methods as those given as examples of the method for drying the coating film of the easy-adhesion layer material in the step (2-2).
  • step (6-1) a liquid top layer material is applied onto the anchor layer of the multi-layered product (III) to form a coating film of the top layer material.
  • Examples of the method include the same methods as those given as examples of the coating method of the liquid easy-adhesion layer material in the step (2-1).
  • the coating thickness of the top layer material can be adjusted so that the top layer has the desired thickness in the resulting multilayer film.
  • step (6-2) the coating film of the top layer material is dried to form a top layer, and a multilayer structure having the base film, the easy-adhesion layer, the anchor layer, and the top layer in this order is obtained.
  • step (IV) is obtained.
  • the method for drying the coating film of the top layer material include the same methods as those given as examples of the method for drying the coating film of the easy-adhesion layer material in step (2-2), and preferably, drying the coating film using an oven. The heat drying method used was
  • step (7) the multilayer product (IV) is stretched to obtain a multilayer film.
  • the stretching of the laminate (IV) in the step (7) is usually carried out in an oven.
  • the stretching direction in step (7) can be set according to the optical properties to be expressed in the multilayer film.
  • the stretching direction in step (7) is the same as that of the multilayer (IV). It is preferable that the stretching direction is substantially parallel to the longitudinal direction.
  • the angle between the stretching direction and the width direction of the laminate (IV) is preferably 85° or more, more preferably 87° or more. It is more preferably 89° or more, and is preferably 95° or less, more preferably 93° or less, further preferably 91° or less, and particularly preferably 90°.
  • the stretching in step (7) may be performed as free uniaxial stretching.
  • Free uniaxial stretching refers to stretching in a certain direction in which no restraining force is applied in any direction other than the direction of stretching.
  • free uniaxial stretching in a direction substantially parallel to the longitudinal direction of the multi-layered product (IV) can be stretching in the longitudinal direction without restraining the ends of the multi-layered product (IV) in the width direction.
  • the stretching ratio in step (7) is preferably 1.1 times or more, more preferably 1.15 times or more, particularly preferably 1.2 times or more, and is preferably 2.0 times or less, more preferably 1.8 times or less, particularly preferably 1.6 times or less.
  • the stretching ratio in step (7) is within the above range, a multilayer film having the desired optical properties can be easily obtained.
  • the film of the present embodiment can be a film with good adhesion.
  • adhesion is an index of resistance to peeling between the base film and the top layer.
  • the adhesion can be measured by a cross-cut test defined in JIS K5600-5-6 (1999). Specifically, the top layer, anchor layer, and easy-adhesion layer of the multilayer film sample are cut at 1 mm intervals in a range of 5 mm x 5 mm to create 25 squares with a side of 1 mm.
  • the adhesion can be evaluated by attaching cellophane tape to the surface of the top layer side of the sample, peeling the cellophane tape, and measuring the number of squares that remain attached to the base film of the multilayer film without peeling. The more squares that remain, the higher the adhesion. In this embodiment, this test can produce an adhesion of 20/25 or more.
  • the good adhesion of the multilayer film can improve the durability of a display device incorporating the multilayer film. In addition, it can facilitate rework during the manufacturing process of the display device. For example, if the multilayer film is attached to a panel containing a display element (such as a liquid crystal cell of a liquid crystal display device) and then it is discovered that there is a defect in the attachment, and the multilayer film is peeled off to reuse the panel, it can reduce the occurrence of defects such as only part of the layers of the multilayer film remaining on the panel.
  • a display element such as a liquid crystal cell of a liquid crystal display device
  • the multilayer film preferably has high transparency. Therefore, it is preferable that the multilayer film has high total light transmittance.
  • the specific total light transmittance of the multilayer film is preferably 80% or more, more preferably 85% or more, and particularly preferably 88% or more.
  • the light transmittance can be measured in the wavelength range of 400 nm to 700 nm using a spectrophotometer in accordance with JIS K0115.
  • the overall thickness of the multilayer film is preferably 30 ⁇ m or more, more preferably 35 ⁇ m or more, and particularly preferably 40 ⁇ m or more, and is preferably 100 ⁇ m or less, more preferably 90 ⁇ m or less, and particularly preferably 80 ⁇ m or less.
  • the multilayer film preferably has a long shape.
  • the width of the long multilayer film is preferably 1300 mm or more, more preferably 1400 mm or more, particularly preferably 1500 mm or more, and is preferably 2000 mm or less, more preferably 1800 mm or less.
  • the multilayer film as a broadband wavelength film may be laminated with a linear polarizer and used to manufacture a circular polarizing plate. Since the above-mentioned multilayer film has small variation in in-plane retardation, a circular polarizing plate equipped with the multilayer film can suppress variation in the polarization state of the circularly polarized light that passes through the circular polarizing plate. Therefore, this circular polarizing plate can be used as a reflection-suppressing film that suppresses light reflection with high uniformity.
  • the weight average particle size of the particles was measured by dynamic light scattering using "Nanotrac UPA-EX150” manufactured by Microtrac Corporation, USA.
  • In-plane retardation Re The in-plane retardation Re of the sample film was measured by a phase difference meter (Axometrics'"AxoScan").
  • the adhesion was evaluated by a cross-cut test according to JIS K5600-5-6 (1999).
  • the top layer, anchor layer, and easy-adhesion layer of the multilayer film sample were cut at 1 mm intervals in a range of 5 mm x 5 mm to create 25 squares with a side of 1 mm.
  • Cellophane tape was attached to the surface of the top layer side of the sample, and the cellophane tape was peeled off.
  • the number of squares remaining on the base film of the multilayer film without peeling off was counted, and was also evaluated according to the following evaluation criteria. Good: The number of remaining squares is between 20/25 and 25/25. Poor: 19/25 or less squares remaining.
  • the multilayer film was placed on a blackboard and the surface condition was visually observed under a fluorescent lamp.
  • the multilayer film was observed in an area of 1 m x 1 m, and foreign matter with a maximum diameter of 100 ⁇ m or more was counted as a defect.
  • Example 1 (1-1. Base Film) Pellet-shaped norbornene-based resin (manufactured by Zeon Corporation; glass transition temperature 126° C.) was dried for 5 hours at 100° C. The dried resin was fed to an extruder, passed through a polymer pipe and a polymer filter, and extruded from a T-die onto a casting drum in the form of a sheet, thereby carrying out extrusion molding. The molded resin was cooled to obtain a long substrate film (i) having a thickness of 70 ⁇ m.
  • the easy-adhesion layer material 1 obtained in (1-2) was applied to the corona-treated surface of the base film (i) to form a coating of the easy-adhesion layer material.
  • the application was performed using a roll coater under conditions such that the coating would have a thickness of 0.1 ⁇ m after drying.
  • the coating of the easy-adhesion layer material was heated at a temperature of 110°C for 60 seconds to form an easy-adhesion layer (i) on the base film (i).
  • the resulting multilayered product (I) was wound up on a roll and collected.
  • the laminate (I) was unwound from the roll.
  • the unwound multilayered product (I) was continuously supplied to a tenter stretching machine, and the multilayered product (I) was stretched by the tenter stretching machine.
  • the stretching direction was a direction forming an angle of 45° with respect to the width direction of the multilayered product (I).
  • the stretching temperature was 135°C, and the stretching ratio was 1.5 times.
  • the substrate film (ii) is a layer obtained as a result of stretching the substrate film (i), and the easy adhesion layer (ii) is a layer obtained as a result of stretching the easy adhesion layer (i).
  • the orientation angle of the substrate film (ii) in the multilayered product (II) with respect to the film width direction was 45°, and the in-plane retardation Re of the multilayered product (II) was 215 nm.
  • the thickness of the base film (ii) in the multilayered product (II) was 47 ⁇ m, and the thickness of the easy-adhesion layer (ii) was 0.085 ⁇ m.
  • the obtained multilayered product (II) was wound around a roll and collected.
  • the laminate (II) obtained in (1-4) was unwound from the roll.
  • the anchor layer material 1 obtained in (1-5) was applied to the surface of the base film (ii) of the unwound multilayered product (II) (i.e., the surface of the easy-adhesion layer (ii)) to form a coating film of the anchor layer material 1.
  • the coating was performed using a reverse gravure that rotates in the opposite direction to the film transport direction.
  • Laminated material (IV) A styrene-maleic anhydride copolymer resin ("Dylark D332" manufactured by Nova Chemical Co.) was prepared as a resin having a negative intrinsic birefringence. A mixed solvent of methyl ethyl ketone and methyl isobutyl ketone (weight ratio 8:2) was also prepared. 100 parts of styrene-maleic anhydride copolymer resin was dissolved in a mixed solvent, and 5 parts of triphenyl phosphate was further added as a plasticizer to obtain a liquid top layer material 1 having a solid content concentration of 15% by weight.
  • Top layer material 1 was applied by die coating to the surface of the resulting anchor layer (i) side to form a coating of top layer material 1.
  • the coating film of the top layer material 1 thus formed was dried at 120°C to form the top layer (i).
  • a long multilayered product (IV) having a layer structure of (top layer (i))/(anchor layer (i))/(easy adhesion layer (ii))/(base film (ii)) was obtained.
  • the thickness of the top layer (i) in the obtained multilayered product (IV) was 8 ⁇ m.
  • the obtained multilayered product (IV) was laminated with a masking film, and then wound up on a roll and collected.
  • the unwound multilayered material (IV) was continuously supplied to a longitudinal stretching machine, and the multilayered material (IV) was stretched by the longitudinal stretching machine.
  • the stretching was performed by free uniaxial stretching in the longitudinal direction of the multilayered material (IV).
  • the stretching temperature was 127°C, and the stretching ratio was 1.4 times.
  • the top layer (ii) is a layer obtained as a result of stretching the top layer (i)
  • the anchor layer (ii) is a layer obtained as a result of stretching the anchor layer (i)
  • the easy adhesion layer (iii) is a layer obtained as a result of stretching the easy adhesion layer (ii)
  • the base film (iii) is a layer obtained as a result of stretching the base film (ii).
  • the appearance of the resulting multilayer film was visually inspected, and the presence or absence of foreign matter in the film was evaluated.
  • the resulting multi-layer film was also evaluated for adhesion and found to have all squares in good adhesion (25/25).
  • Example 2 In (1-3), the coating conditions using a roll coater were adjusted to change the thickness of the coating of the adhesive layer material so that the thickness of the adhesive layer in the multilayer film was as shown in the table. Except for the above, the same procedure as in Example 1 was repeated to obtain a multilayer film and evaluate it.
  • Example 3 In (1-2), as the organic particles (NP), "Eposter MX100W” (weight average particle diameter 150 nm, solid content concentration 10%) manufactured by Nippon Shokubai Co., Ltd. was used instead of “Eposter MX200W” (weight average particle diameter 300 nm) manufactured by Nippon Shokubai Co., Ltd. Except for the above, the same procedure as in Example 1 was repeated to obtain a multilayer film and evaluate it.
  • *1 indicates that when unrolling the laminate (II) in (1-6), wrinkles occurred in the laminate (II), making it impossible to apply the anchor layer material, and therefore no laminate film could be obtained, and therefore evaluation was not possible.
  • the multilayer films according to Examples 1 to 3 are evaluated as having good adhesion.
  • the multilayer film according to Example 1 in which T1/T3 is 0.6 or less, has zero defects, and it is understood that the multilayer film can achieve high standards of adhesion and fewer defects.
  • the multilayer film manufacturing methods according to Examples 1 to 3 can provide multilayer films with excellent adhesion.
  • the desired multilayer film cannot be obtained in the method for producing a multilayer film according to Comparative Example 3, in which T3 is less than T1, i.e., T1/T3 is greater than 1. This is presumably because the slipperiness of the multilayer material (II) obtained in the middle is insufficient.

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Abstract

Provided is a multilayer film comprising a base film, an easily adhering layer provided in direct contact with one surface of the base film, an anchor layer provided in direct contact with the surface of the easily adhering layer, and a top layer provided direct contact with the surface of the anchor layer. The total thickness (T1 + T2) of the thickness T1 of the easily adhering layer and the thickness T2 of the anchor layer is 150 nm or greater. The easily adhering layer includes organic particles (NP) having an average particle diameter T3 equal to or greater than the thickness T1 of the easily adhering layer.

Description

複層フィルム及びその製造方法Multilayer film and its manufacturing method
　本発明は、複層フィルム及びその製造方法に関する。 The present invention relates to a multilayer film and a method for producing the same.
　基材フィルムと粒子を含む樹脂層とを備える複層フィルムが知られている（特許文献１～３参照）。 　Multilayer films that have a base film and a resin layer that contains particles are known (see Patent Documents 1 to 3).
特開２０２０－０２３１７０号公報JP 2020-023170 A 特開２０１８－１１８４３８号公報JP 2018-118438 A 特開２０２０－０２３１７１号公報JP 2020-023171 A
　基材フィルムと、光学的機能を備える位相差層などの、基材フィルム以外の他の機能層との複層物は、基材フィルムと光学的機能層などの機能層との密着性が十分でない場合がある。このような場合、基材フィルムに、機能層との密着性を向上させるための易接着層を設けることがある。さらに、基材フィルムの滑り性を向上させるために、易接着層に粒子を含有させることがある。
　しかし、粒子を含有する易接着層を備えていると、基材フィルムと機能層との密着性が十分でない場合がある。
　したがって、基材フィルムと他の機能層との密着性が良好な複層フィルム；かかる密着性が良好な複層フィルムを製造する方法；が求められる。 In the case of a laminate of a substrate film and a functional layer other than the substrate film, such as a retardation layer having an optical function, the adhesion between the substrate film and the functional layer, such as the optical functional layer, may be insufficient. In such a case, an easy-adhesion layer may be provided on the substrate film to improve the adhesion with the functional layer. Furthermore, in order to improve the slippage of the substrate film, particles may be included in the easy-adhesion layer.
However, when the film has an easy-adhesion layer containing particles, the adhesion between the base film and the functional layer may be insufficient.
Therefore, there is a need for a multilayer film having good adhesion between the base film and other functional layers; and a method for producing such a multilayer film having good adhesion.
　本発明者は、前記課題を解決するべく、鋭意検討した。その結果、基材フィルムと、特定の易接着層と、アンカー層と、トップ層とを備える複層フィルムであって、易接着層の厚みＴ１とアンカー層の厚みＴ２との合計厚み（Ｔ１＋Ｔ２）が、所定の値以上である複層フィルムにより、前記課題が解決できることを見出し、本発明を完成させた。
　すなわち、本発明は、以下を提供する。 The present inventors have conducted extensive research to solve the above problems, and have found that the above problems can be solved by a multilayer film including a base film, a specific easy-adhesion layer, an anchor layer, and a top layer, in which the total thickness (T1+T2) of the easy-adhesion layer thickness T1 and the anchor layer thickness T2 is a predetermined value or more, and have completed the present invention.
That is, the present invention provides the following.
　［１］　基材フィルムと、前記基材フィルムの一方の表面に直接接して設けられた易接着層と、前記易接着層の表面に直接接して設けられたアンカー層と、前記アンカー層の表面に直接接して設けられたトップ層とを備える複層フィルムであって、
　前記易接着層の厚みＴ１と前記アンカー層の厚みＴ２との合計厚み（Ｔ１＋Ｔ２）が、１５０ｎｍ以上であり、
　前記易接着層は、平均粒子径Ｔ３が前記易接着層の厚みＴ１以上である有機粒子（ＮＰ）を含む、
　複層フィルム。
　［２］　前記易接着層の厚みＴ１の前記有機粒子（ＮＰ）の平均粒子径Ｔ３に対する比率（Ｔ１／Ｔ３）が、０．６以下である、［１］に記載の複層フィルム。
　［３］　前記基材フィルムが、環状オレフィン系重合体を含む、［１］又は［２］に記載の複層フィルム。
　［４］　前記有機粒子（ＮＰ）が（メタ）アクリル重合体の粒子である、［１］～［３］のいずれか一項に記載の複層フィルム。
　［５］　前記易接着層が、前記有機粒子（ＮＰ）と（メタ）アクリル酸エステル単位を有する重合体（Ｐ１）と架橋剤（１）とを含む易接着層材料の、硬化物である、［１］～［４］のいずれか一項に記載の複層フィルム。
　［６］　前記アンカー層が、（メタ）アクリル酸エステル単位を有する重合体（Ｐ２）及び架橋剤（２）を含むアンカー層材料の、硬化物である、［１］～［５］のいずれか一項に記載の複層フィルム。
　［７］　前記易接着層が、前記有機粒子（ＮＰ）と（メタ）アクリル酸エステル単位を有する重合体（Ｐ１）と架橋剤（１）とを含む易接着層材料の、硬化物であり、
　前記アンカー層が、（メタ）アクリル酸エステル単位を有する重合体（Ｐ２）及び架橋剤（２）を含むアンカー層材料の、硬化物であり、
　前記重合体（Ｐ１）と前記重合体（Ｐ２）とが、共通する（メタ）アクリル酸エステル単位を有する、［１］～［６］のいずれか一項に記載の複層フィルム。
　［８］　前記トップ層が、スチレン系単量体単位を有する重合体（Ｐ３）を含むトップ層材料の、硬化物である、［１］～［７］のいずれか一項に記載の複層フィルム。
　［９］　延伸フィルムである、［１］～［８］のいずれか一項に記載の複層フィルム。
　［１０］　［１］～［９］のいずれか一項に記載の複層フィルムの製造方法であって、
　長尺の基材フィルムを用意する工程（１）、
　前記基材フィルム上に、液状の易接着層材料を塗布し、前記易接着層材料の塗膜を形成する工程（２－１）、
　前記易接着層材料の塗膜を乾燥させて易接着層を形成し、前記基材フィルムと前記易接着層とを備える複層物（Ｉ）を得る工程（２－２）、
　前記複層物（Ｉ）を延伸して、複層物（ＩＩ）を得る工程（３）、
　前記複層物（ＩＩ）を巻き取る工程（４）、
　巻き取られた前記複層物（ＩＩ）を巻き出し、前記複層物（ＩＩ）の前記易接着層上に、液状のアンカー層材料を塗布し、前記アンカー層材料の塗膜を形成する工程（５－１）、
　前記アンカー層材料の塗膜を乾燥させてアンカー層を形成し、前記基材フィルムと前記易接着層と前記アンカー層とをこの順で備える複層物（ＩＩＩ）を得る工程（５－２）、
　前記複層物（ＩＩＩ）の前記アンカー層上に、液状のトップ層材料を塗布し、前記トップ層材料の塗膜を形成する工程（６－１）、
　前記トップ層材料の塗膜を乾燥させてトップ層を形成し、前記基材フィルムと前記易接着層と前記アンカー層と前記トップ層とをこの順で備える複層物（ＩＶ）を得る工程（６－２）、及び
　前記複層物（ＩＶ）を延伸して複層フィルムを得る工程（７）、
を含む、複層フィルムの製造方法。 [1] A multilayer film comprising a base film, an easy-adhesion layer provided in direct contact with one surface of the base film, an anchor layer provided in direct contact with the surface of the easy-adhesion layer, and a top layer provided in direct contact with the surface of the anchor layer,
The total thickness (T1 + T2) of the thickness T1 of the easy-adhesion layer and the thickness T2 of the anchor layer is 150 nm or more,
The easy-adhesion layer contains organic particles (NP) having an average particle diameter T3 equal to or greater than the thickness T1 of the easy-adhesion layer,
Multi-layer film.
[2] The multilayer film according to [1], wherein the ratio (T1/T3) of the thickness T1 of the easy-adhesion layer to the average particle diameter T3 of the organic particles (NP) is 0.6 or less.
[3] The multilayer film according to [1] or [2], wherein the base film contains a cyclic olefin polymer.
[4] The multilayer film according to any one of [1] to [3], wherein the organic particles (NP) are particles of a (meth)acrylic polymer.
[5] The easy-adhesion layer is a cured product of an easy-adhesion layer material containing the organic particles (NP), a polymer (P1) having a (meth)acrylic acid ester unit, and a crosslinking agent (1). [1]-[4] Any one of the multilayer film described.
[6] The multilayer film according to any one of [1] to [5], wherein the anchor layer is a cured product of an anchor layer material containing a polymer (P2) having a (meth)acrylic acid ester unit and a crosslinking agent (2).
[7] The easy-adhesion layer is a cured product of an easy-adhesion layer material containing the organic particles (NP), a polymer (P1) having a (meth)acrylic acid ester unit, and a crosslinking agent (1),
the anchor layer is a cured product of an anchor layer material containing a polymer (P2) having a (meth)acrylic acid ester unit and a crosslinking agent (2),
The multilayer film according to any one of [1] to [6], wherein the polymer (P1) and the polymer (P2) have a common (meth)acrylic acid ester unit.
[8] The multilayer film according to any one of [1] to [7], wherein the top layer is a cured product of a top layer material containing a polymer (P3) having a styrene-based monomer unit.
[9] The multilayer film according to any one of [1] to [8], which is a stretched film.
[10] A method for producing the multilayer film according to any one of [1] to [9],
A step (1) of preparing a long substrate film;
A step (2-1) of applying a liquid adhesive layer material onto the substrate film to form a coating film of the adhesive layer material;
A step (2-2) of drying the coating film of the easy-adhesion layer material to form an easy-adhesion layer and obtain a multilayer body (I) having the base film and the easy-adhesion layer;
A step (3) of stretching the multi-layered product (I) to obtain a multi-layered product (II);
A step (4) of winding up the laminate (II);
A step (5-1) of unwinding the wound multilayer material (II) and applying a liquid anchor layer material onto the easy-adhesion layer of the multilayer material (II) to form a coating film of the anchor layer material;
A step (5-2) of drying the coating film of the anchor layer material to form an anchor layer, thereby obtaining a multilayer body (III) having the base film, the easy-adhesion layer, and the anchor layer in this order;
A step (6-1) of applying a liquid top layer material onto the anchor layer of the multilayer structure (III) to form a coating film of the top layer material;
A step (6-2) of drying the coating film of the top layer material to form a top layer and obtaining a multilayer body (IV) having the base film, the easy-adhesion layer, the anchor layer, and the top layer in this order; and A step (7) of stretching the multilayer body (IV) to obtain a multilayer film.
A method for producing a multilayer film, comprising:
　本発明によれば、基材フィルムと他の機能層との密着性が良好な複層フィルム；かかる密着性が良好な複層フィルムを製造する方法；を提供できる。 The present invention provides a multilayer film having good adhesion between the base film and other functional layers; and a method for producing such a multilayer film having good adhesion.
　以下、本発明について実施形態及び例示物を示して詳細に説明する。ただし、本発明は以下に示す実施形態及び例示物に限定されるものではなく、本発明の請求の範囲及びその均等の範囲を逸脱しない範囲において任意に変更して実施しうる。以下に示す実施形態の構成要素は、適宜組み合わせうる。 The present invention will be described in detail below with reference to embodiments and examples. However, the present invention is not limited to the embodiments and examples shown below, and may be modified and implemented as desired without departing from the scope of the claims of the present invention and their equivalents. The components of the embodiments shown below may be combined as appropriate.
　以下の説明において、「長尺」のフィルムとは、幅に対して、５倍以上の長さを有するフィルムをいい、好ましくは１０倍若しくはそれ以上の長さを有し、具体的にはロール状に巻き取られて保管又は運搬される程度の長さを有するフィルムをいう。フィルムの長さの上限は、特に制限は無く、例えば、幅に対して１０万倍以下としうる。 In the following description, a "long" film refers to a film that is 5 times or more longer than its width, and preferably 10 times or more longer, specifically a film long enough to be wound into a roll for storage or transportation. There is no particular upper limit to the length of the film, and it can be, for example, 100,000 times or less than its width.
　以下の説明において、フィルム又は層の遅相軸とは、別に断らない限り、当該フィルム又は層の面内における遅相軸を表す。 In the following description, the slow axis of a film or layer refers to the slow axis in the plane of the film or layer, unless otherwise specified.
　以下の説明において、フィルム又は層の配向角とは、別に断らない限り、当該フィルム又は層の遅相軸が、当該フィルム又は層の長手方向に対してなす角度を表す。 In the following description, unless otherwise specified, the orientation angle of a film or layer refers to the angle that the slow axis of the film or layer makes with the longitudinal direction of the film or layer.
　以下の説明において、複数の層を備える部材における各層の光学軸（遅相軸、透過軸、吸収軸等）がなす角度は、別に断らない限り、前記の層を厚み方向から見たときの角度を表す。 In the following description, the angle between the optical axes (slow axis, transmission axis, absorption axis, etc.) of each layer in a component having multiple layers represents the angle when the layer is viewed from the thickness direction, unless otherwise specified.
　以下の説明において、長尺のフィルムの斜め方向とは、別に断らない限り、そのフィルムの面内方向であって、そのフィルムの長手方向に平行でもなく垂直でもない方向を示す。 In the following explanation, unless otherwise specified, the diagonal direction of a long film refers to an in-plane direction of the film that is neither parallel nor perpendicular to the longitudinal direction of the film.
　以下の説明において、層の面内レターデーションＲｅは、別に断らない限り、Ｒｅ＝（ｎｘ－ｎｙ）×ｄで表される値である。ここで、ｎｘは、層の厚み方向に垂直な方向（面内方向）であって最大の屈折率を与える方向の屈折率を表す。ｎｙは、層の前記面内方向であってｎｘの方向に直交する方向の屈折率を表す。ｄは、層の厚みを表す。測定波長は、別に断らない限り、５５０ｎｍである。 In the following description, the in-plane retardation Re of a layer is a value expressed as Re = (nx - ny) x d, unless otherwise specified. Here, nx represents the refractive index in the direction perpendicular to the thickness direction of the layer (in-plane direction) that gives the maximum refractive index. ny represents the refractive index in the in-plane direction of the layer that is perpendicular to the direction of nx. d represents the thickness of the layer. The measurement wavelength is 550 nm, unless otherwise specified.
　以下の説明において、要素の方向が「平行」、「垂直」及び「直交」とは、別に断らない限り、本発明の効果を損ねない範囲内、例えば±３°、±２°又は±１°の範囲内での誤差を含んでいてもよい。 In the following description, unless otherwise specified, the directions of elements as "parallel," "vertical," and "orthogonal" may include an error within a range that does not impair the effect of the present invention, for example, within the range of ±3°, ±2°, or ±1°.
　「正の固有複屈折を有する樹脂」とは、別に断らない限り、延伸方向の屈折率が延伸方向に直交する方向の屈折率よりも大きくなる樹脂を表す。また、「正の固有複屈折を有する重合体」とは、別に断らない限り、延伸方向の屈折率が延伸方向に直交する方向の屈折率よりも大きくなる重合体を表す。 Unless otherwise specified, a "resin with positive inherent birefringence" refers to a resin whose refractive index in the stretching direction is greater than the refractive index in the direction perpendicular to the stretching direction. Additionally, a "polymer with positive inherent birefringence" refers to a polymer whose refractive index in the stretching direction is greater than the refractive index in the direction perpendicular to the stretching direction, unless otherwise specified.
　「負の固有複屈折を有する樹脂」とは、別に断らない限り、延伸方向の屈折率が延伸方向に直交する方向の屈折率よりも小さくなる樹脂を表す。「負の固有複屈折を有する重合体」とは、別に断らない限り、延伸方向の屈折率が延伸方向に直交する方向の屈折率よりも小さくなる重合体を表す。 Unless otherwise specified, "resin with negative inherent birefringence" refers to a resin whose refractive index in the stretching direction is smaller than the refractive index in the direction perpendicular to the stretching direction. "polymer with negative inherent birefringence" refers to a polymer whose refractive index in the stretching direction is smaller than the refractive index in the direction perpendicular to the stretching direction, unless otherwise specified.
　以下の説明において、「（メタ）アクリル」の文言は、「アクリル」、「メタクリル」及びこれらの組み合わせを包含する。
　「（メタ）アクリル酸」の文言は、「アクリル酸」、「メタクリル酸」及びこれらの組み合わせを包含する。
　「（メタ）アクリロニトリル」の文言は、「アクリロニトリル」、「メタクリロニトリル」及びこれらの組み合わせを包含する。
　「（メタ）アクリレート」の文言は、「アクリレート」、「メタクリレート」及びこれらの組み合わせを包含する。 In the following description, the term "(meth)acrylic" includes "acrylic", "methacrylic" and combinations thereof.
The term "(meth)acrylic acid" encompasses "acrylic acid,""methacrylicacid," and combinations thereof.
The term "(meth)acrylonitrile" includes "acrylonitrile", "methacrylonitrile", and combinations thereof.
The term "(meth)acrylate" encompasses "acrylate,""methacrylate," and combinations thereof.
　以下の説明において、ある単量体の重合により形成される構造を有する重合単位を、当該単量体の名称を用いて表現する場合がある。例えば、（メタ）アクリル酸エステルの重合により形成される構造を有する単位を、「（メタ）アクリル酸エステル単位」と称する場合がある。また、スチレン系単量体の重合により形成される構造を有する単位を、「スチレン系単量体単位」と称する場合がある。さらに、スチレン系単量体単位を含む重合体を、単にスチレン系重合体という場合がある。但し本発明において、分子及びその構成要素の構造は、その製造方法によっては限定されない。 In the following description, a polymerized unit having a structure formed by polymerization of a certain monomer may be expressed using the name of that monomer. For example, a unit having a structure formed by polymerization of a (meth)acrylic acid ester may be referred to as a "(meth)acrylic acid ester unit." Also, a unit having a structure formed by polymerization of a styrene-based monomer may be referred to as a "styrene-based monomer unit." Furthermore, a polymer containing a styrene-based monomer unit may simply be referred to as a styrene-based polymer. However, in the present invention, the structure of the molecule and its components is not limited by the manufacturing method.
　以下の説明において、「ある層Ａが、ある層Ｂの一方の表面に直接接して設けられている」とは、層Ｂの一方の表面と層Ａとの間に、他の任意の層が介在していないことを意味する。 In the following description, "a layer A is provided in direct contact with one surface of a layer B" means that there is no other layer between one surface of layer B and layer A.
［１．複層フィルムの概要］
　本発明の一実施形態に係る複層フィルムは、基材フィルムと、前記基材フィルムの一方の表面に直接接して設けられた易接着層と、前記易接着層の表面に直接接して設けられたアンカー層と、前記アンカー層の表面に直接接して設けられたトップ層とを備える。また、前記易接着層の厚みＴ１と前記アンカー層の厚みＴ２との合計厚み（Ｔ１＋Ｔ２）が、１５０ｎｍ以上であり、前記易接着層は、平均粒子径Ｔ３が前記易接着層の厚みＴ１以上である有機粒子（ＮＰ）を含む。
　以下においては主に、易接着層、アンカー層、及びトップ層をそれぞれ１層ずつ有する複層フィルムを例として説明を行う。但し、本発明はこれに限られない。例えば、複層フィルムは１層の基材フィルムの両方の主面のそれぞれの上に設けられた易接着層、アンカー層及びトップ層を有していてもよい。 [1. Overview of multi-layer film]
A multilayer film according to one embodiment of the present invention includes a substrate film, an easy-adhesion layer provided directly on one surface of the substrate film, an anchor layer provided directly on the surface of the easy-adhesion layer, and a top layer provided directly on the surface of the anchor layer. The total thickness (T1+T2) of the easy-adhesion layer thickness T1 and the anchor layer thickness T2 is 150 nm or more, and the easy-adhesion layer contains organic particles (NP) whose average particle diameter T3 is equal to or greater than the thickness T1 of the easy-adhesion layer.
In the following, a multilayer film having one each of an easy-adhesion layer, an anchor layer, and a top layer will be mainly described as an example. However, the present invention is not limited thereto. For example, the multilayer film may have an easy-adhesion layer, an anchor layer, and a top layer provided on both main surfaces of a single-layer base film.
　複層フィルムが前記の構成を備えることにより、密着性が良好なフィルムとしうる。ここで密着性とは、基材フィルムとトップ層との間の、剥離に対する抵抗性の指標である。 The multilayer film has the above-mentioned structure, making it possible to produce a film with good adhesion. Here, adhesion is an index of resistance to peeling between the base film and the top layer.
　さらに、易接着層が前記の構成を備えることにより、中間に製造される基材フィルムと易接着層との複層物が良好な滑り性を備えるため、複層物を製造途中で巻き回しても複層物に傷がつきにくく、かつ円滑に巻き出すことができる。したがって、密着性が良好な複層フィルムを、容易に製造することができる。 Furthermore, by having the easy-adhesion layer have the above-mentioned configuration, the laminate of the base film and the easy-adhesion layer produced in the middle has good slip properties, so that the laminate is less likely to be scratched even if it is rolled up during production, and can be smoothly unrolled. Therefore, a multilayer film with good adhesion can be easily produced.
　合計厚み（Ｔ１＋Ｔ２）は、好ましくは８０ｎｍ以上、より好ましくは１００ｎｍ以上、更に好ましくは１１０ｎｍ以上、更に好ましくは１５０ｎｍ以上、更に好ましくは１６０ｎｍ以上、更に好ましくは１６５ｎｍ以上であり、複層フィルムに与える光学特性への影響を少なくする観点から、好ましくは８００ｎｍ以下、より好ましくは７００ｎｍ以下、更に好ましくは５００ｎｍ以下である。 The total thickness (T1+T2) is preferably 80 nm or more, more preferably 100 nm or more, even more preferably 110 nm or more, even more preferably 150 nm or more, even more preferably 160 nm or more, even more preferably 165 nm or more, and from the viewpoint of minimizing the effect on the optical properties of the multilayer film, it is preferably 800 nm or less, more preferably 700 nm or less, even more preferably 500 nm or less.
　複層フィルムが備える層の厚みは、反射分光式膜厚測定装置（例えば、フィルメトリクス社製反射分光式膜厚測定システム「Ｆ２０」）により測定しうる。 The thickness of the layers in the multilayer film can be measured using a spectroscopic reflection film thickness measuring device (e.g., the F20 spectroscopic reflection film thickness measuring system manufactured by Filmetrics).
　前記易接着層の厚みＴ１の有機粒子（ＮＰ）の平均粒子径Ｔ３に対する比率（Ｔ１／Ｔ３）は、通常１／１以下（すなわち、１以下）、好ましくは０．８以下、より好ましくは０．６以下、更に好ましくは０．４６以下であり、通常０より大きく、例えば、０．１以上であってもよい。Ｔ１／Ｔ３が前記範囲内であると、複層フィルムの密着性と複層フィルムの面状態との双方を良好にしうる。 The ratio (T1/T3) of the thickness T1 of the easy-adhesion layer to the average particle diameter T3 of the organic particles (NP) is usually 1/1 or less (i.e., 1 or less), preferably 0.8 or less, more preferably 0.6 or less, and even more preferably 0.46 or less, and may usually be greater than 0, for example, 0.1 or more. When T1/T3 is within the above range, both the adhesion of the multilayer film and the surface condition of the multilayer film can be improved.
　有機粒子（ＮＰ）の平均粒子径Ｔ３は、例えば１００ｎｍ以上、例えば１５０ｎｍ以上であり、例えば１０００ｎｍ以下、例えば８００ｎｍ以下である。 The average particle diameter T3 of the organic particles (NP) is, for example, 100 nm or more, for example, 150 nm or more, and is, for example, 1000 nm or less, for example, 800 nm or less.
　本明細書において、有機粒子（ＮＰ）の平均粒子径Ｔ３は、動的光散乱法により測定された、重量平均粒子径である。 In this specification, the average particle diameter T3 of the organic particles (NP) is the weight average particle diameter measured by dynamic light scattering.
［１．１．基材フィルム］
　基材フィルムとしては、熱可塑性樹脂を含むフィルムを用いうる。以下、基材フィルムに含まれうる熱可塑性樹脂を熱可塑性樹脂（ｓ）ともいう。基材フィルムは、熱可塑性樹脂（ｓ）のみからなるフィルムとしうる。
　好ましくは、熱可塑性樹脂（ｓ）としては、重合体を含み、必要に応じて更に任意の成分を含む熱可塑性樹脂を用いる。熱可塑性樹脂（ｓ）として、負の固有複屈折を有する樹脂を用いてもよいが、広帯域波長フィルムとしての複層フィルムを容易に製造する観点では、正の固有複屈折を有する樹脂が好ましい。 [1.1. Base film]
The base film may be a film containing a thermoplastic resin. Hereinafter, the thermoplastic resin that may be contained in the base film may be referred to as a thermoplastic resin (s). The base film may be a film made of only the thermoplastic resin (s).
Preferably, the thermoplastic resin (s) is a thermoplastic resin containing a polymer and further containing an optional component as necessary. Although a resin having a negative inherent birefringence may be used as the thermoplastic resin (s), a resin having a positive inherent birefringence is preferred from the viewpoint of easily manufacturing a multilayer film as a broadband wavelength film.
　正の固有複屈折を有する樹脂は、通常、正の固有複屈折を有する重合体を含む。正の固有複屈折を有する重合体の例を挙げると、ポリエチレン、ポリプロピレン等のポリオレフィン；ポリエチレンテレフタレート、ポリブチレンテレフタレート等のポリエステル；ポリフェニレンサルファイド等のポリアリーレンサルファイド；ポリビニルアルコール；ポリカーボネート；ポリアリレート；セルロースエステル重合体；ポリエーテルスルホン；ポリスルホン；ポリアリルサルホン；ポリ塩化ビニル；ノルボルネン系重合体等の脂環式構造含有重合体；棒状液晶ポリマーなどが挙げられる。これらの重合体は、１種類を単独で用いてもよく、２種類以上を任意の比率で組み合わせて用いてもよい。また、重合体は、単独重合体でもよく、共重合体でもよい。 　Resins having positive intrinsic birefringence usually include polymers having positive intrinsic birefringence. Examples of polymers having positive intrinsic birefringence include polyolefins such as polyethylene and polypropylene; polyesters such as polyethylene terephthalate and polybutylene terephthalate; polyarylene sulfides such as polyphenylene sulfide; polyvinyl alcohol; polycarbonate; polyarylate; cellulose ester polymers; polyethersulfone; polysulfone; polyarylsulfone; polyvinyl chloride; alicyclic structure-containing polymers such as norbornene-based polymers; rod-shaped liquid crystal polymers, and the like. These polymers may be used alone or in combination of two or more types in any ratio. The polymers may be homopolymers or copolymers.
　熱可塑性樹脂（ｓ）に含まれる重合体としては、機械特性、耐熱性、透明性、低吸湿性、寸法安定性及び軽量性に優れるので、脂環式構造含有重合体が好ましい。脂環式構造を含有する重合体の例としては、環状オレフィン系重合体、すなわち、環状オレフィンを重合して得られる構造を有する構成単位を含む重合体及びその水素添加物が挙げられる。 As the polymer contained in the thermoplastic resin (s), a polymer containing an alicyclic structure is preferable because it has excellent mechanical properties, heat resistance, transparency, low moisture absorption, dimensional stability, and light weight. Examples of polymers containing an alicyclic structure include cyclic olefin polymers, that is, polymers containing structural units having a structure obtained by polymerizing cyclic olefins, and hydrogenated products thereof.
　環状オレフィン系重合体である脂環式構造含有重合体の例としては、（１）ノルボルネン系重合体、（２）単環の環状オレフィン重合体、（３）環状共役ジエン重合体、（４）ビニル脂環式炭化水素重合体、及びこれらの水素添加物などが挙げられる。これらの中でも、ノルボルネン系重合体が好ましい。ノルボルネン系重合体としては、例えば、ノルボルネンモノマーの開環重合体、ノルボルネンモノマーと開環共重合可能なその他のモノマーとの開環共重合体、及びそれらの水素添加物；ノルボルネンモノマーの付加重合体、ノルボルネンモノマーと共重合可能なその他のモノマーとの付加共重合体などが挙げられる。これらの中でも、透明性の観点から、ノルボルネンモノマーの開環重合体の水素添加物が特に好ましい。脂環式構造含有重合体は、例えば特開２００２－３２１３０２号公報等に開示されている重合体から選ばれる。 Examples of cycloolefin-based polymers that contain an alicyclic structure include (1) norbornene-based polymers, (2) monocyclic olefin polymers, (3) cyclic conjugated diene polymers, (4) vinyl alicyclic hydrocarbon polymers, and hydrogenated products thereof. Of these, norbornene-based polymers are preferred. Examples of norbornene-based polymers include ring-opening polymers of norbornene monomers, ring-opening copolymers of norbornene monomers and other monomers that can be copolymerized by ring-opening, and hydrogenated products thereof; addition polymers of norbornene monomers, and addition copolymers of norbornene monomers and other monomers that can be copolymerized. Of these, hydrogenated products of ring-opening polymers of norbornene monomers are particularly preferred from the viewpoint of transparency. The alicyclic structure-containing polymer is selected from the polymers disclosed in, for example, JP-A-2002-321302.
　熱可塑性樹脂（ｓ）における重合体の割合は、好ましくは５０重量％～１００重量％、より好ましくは７０重量％～１００重量％、特に好ましくは９０重量％～１００重量％である。重合体の割合が前記範囲にある場合、耐熱性及び透明性に優れる複層フィルムを製造できる。 The polymer ratio in the thermoplastic resin (s) is preferably 50% to 100% by weight, more preferably 70% to 100% by weight, and particularly preferably 90% to 100% by weight. When the polymer ratio is within the above range, a multilayer film with excellent heat resistance and transparency can be produced.
　熱可塑性樹脂（ｓ）は、重合体に組み合わせて、更に前記重合体以外の任意の成分を含みうる。任意の成分としては、例えば、顔料、染料等の着色剤；可塑剤；蛍光増白剤；分散剤；熱安定剤；光安定剤；紫外線吸収剤；帯電防止剤；酸化防止剤；微粒子；界面活性剤等が挙げられる。これらの成分は、１種類を単独で用いてもよく、２種類以上を任意の比率で組み合わせて用いてもよい。 The thermoplastic resin (s) may further contain optional components other than the polymer in combination with the polymer. Examples of optional components include colorants such as pigments and dyes; plasticizers; fluorescent whitening agents; dispersants; heat stabilizers; light stabilizers; UV absorbers; antistatic agents; antioxidants; fine particles; surfactants, etc. One of these components may be used alone, or two or more may be used in combination in any ratio.
　熱可塑性樹脂（ｓ）のガラス転移温度ＴｇＡは、好ましくは１００℃以上、より好ましくは１１０℃以上、特に好ましくは１２０℃以上であり、好ましくは１９０℃以下、より好ましくは１８０℃以下、特に好ましくは１７０℃以下である。熱可塑性樹脂（ｓ）のガラス転移温度ＴｇＡが前記範囲の下限値以上である場合、基材フィルムの高温環境下における耐久性を高めることができる。また、熱可塑性樹脂（ｓ）のガラス転移温度ＴｇＡが前記範囲の上限値以下である場合、延伸処理を容易に行える。ガラス転移温度は、示差走査熱量分析計（ＳＩＩナノテクノロジー社製、製品名：ＤＳＣ６２２０）を用いて、ＪＩＳ－Ｋ７１２１に基づき、昇温速度１０℃／分の条件で測定しうる。 The glass transition temperature TgA of the thermoplastic resin (s) is preferably 100°C or higher, more preferably 110°C or higher, particularly preferably 120°C or higher, and is preferably 190°C or lower, more preferably 180°C or lower, particularly preferably 170°C or lower. When the glass transition temperature TgA of the thermoplastic resin (s) is equal to or higher than the lower limit of the above range, the durability of the substrate film in a high-temperature environment can be improved. When the glass transition temperature TgA of the thermoplastic resin (s) is equal to or lower than the upper limit of the above range, the stretching process can be easily performed. The glass transition temperature can be measured using a differential scanning calorimeter (manufactured by SII Nanotechnology, product name: DSC6220) at a heating rate of 10°C/min according to JIS-K7121.
　熱可塑性樹脂（ｓ）は、粒子を含まないことが好ましい。本願において、粒子を「含まない」とは、実質的に粒子を含まない場合をも包含しうる。実質的に粒子を含まない場合とは、熱可塑性樹脂（ｓ）が粒子を含む場合であって、粒子を全く含まない状態と対比した基材フィルムのヘイズの上昇幅が０．０５％以下の範囲である場合を意味する。 The thermoplastic resin (s) preferably does not contain particles. In this application, "not containing" particles can also include the case where the resin does not substantially contain particles. The case where the resin does not substantially contain particles means that the thermoplastic resin (s) contains particles, and the increase in haze of the base film compared to a state where the resin does not contain any particles is within a range of 0.05% or less.
　基材フィルムは、光学等方性を有していてもよく、よって、遅相軸を有していなくてもよい。また、基材フィルムは、光学異方性を有していてもよく、よって、遅相軸を有していてもよい。延伸前の複層フィルムに含まれる基材フィルムが遅相軸を有する場合、その遅相軸の方向は、延伸後の複層フィルムの所望の光学的性質が得られる範囲で任意に設定しうる。 The base film may have optical isotropy and therefore may not have a slow axis. The base film may also have optical anisotropy and therefore may have a slow axis. If the base film contained in the multilayer film before stretching has a slow axis, the direction of the slow axis can be set arbitrarily within the range in which the desired optical properties of the multilayer film after stretching can be obtained.
　基材フィルムの面内レターデーションＲｅは、特に制限は無いが、好ましくは１９０ｎｍ以上、より好ましくは２００ｎｍ以上、特に好ましくは２０５ｎｍ以上であり、好ましくは３００ｎｍ以下、より好ましくは２８０ｎｍ以下、特に好ましくは２６０ｎｍ以下である。基材フィルムの面内レターデーションＲｅは、測定波長５５０ｎｍにおける面内レターデーションを表す。 The in-plane retardation Re of the substrate film is not particularly limited, but is preferably 190 nm or more, more preferably 200 nm or more, particularly preferably 205 nm or more, and is preferably 300 nm or less, more preferably 280 nm or less, particularly preferably 260 nm or less. The in-plane retardation Re of the substrate film represents the in-plane retardation at a measurement wavelength of 550 nm.
　基材フィルムの厚みは、特段の制限は無いが、好ましくは３０μｍ以上、より好ましくは３５μｍ以上、特に好ましくは４０μｍ以上であり、好ましくは６０μｍ以下、より好ましくは５５μｍ以下、特に好ましくは５０μｍ以下である。 There are no particular limitations on the thickness of the base film, but it is preferably 30 μm or more, more preferably 35 μm or more, particularly preferably 40 μm or more, and preferably 60 μm or less, more preferably 55 μm or less, particularly preferably 50 μm or less.
　基材フィルムの表面は、改質処理がされていてもよい。改質処理により、基材フィルムと易接着層との密着性を向上させうる。改質処理の例としては、エネルギー線照射処理及び薬品処理が挙げられる。エネルギー線照射処理としては、例えば、コロナ処理、プラズマ処理、電子線照射処理、紫外線照射処理等が挙げられ、処理効率の点等から、コロナ処理、プラズマ処理が好ましく、コロナ処理が特に好ましい。また、薬品処理としては、例えば、ケン化処理、重クロム酸カリウム溶液、濃硫酸等の酸化剤水溶液中に浸漬し、その後、水で洗浄する方法が挙げられる。
　コロナ処理の出力は、処理対象面のダメージをできるだけ少なく処理する条件が好ましく、具体的には、好ましくは０．０２ｋＷ以上、より好ましくは０．０４ｋＷ以上であり、好ましくは５ｋＷ以下、より好ましくは２ｋＷ以下である。 The surface of the substrate film may be modified. The modification can improve the adhesion between the substrate film and the easy-adhesion layer. Examples of the modification include energy ray irradiation and chemical treatment. Examples of the energy ray irradiation include corona treatment, plasma treatment, electron beam irradiation, and ultraviolet ray irradiation. From the viewpoint of treatment efficiency, corona treatment and plasma treatment are preferred, and corona treatment is particularly preferred. Examples of the chemical treatment include saponification, immersion in an aqueous solution of an oxidizing agent such as potassium dichromate or concentrated sulfuric acid, and then washing with water.
The output of the corona treatment is preferably set to a condition that minimizes damage to the surface to be treated, specifically, it is preferably 0.02 kW or more, more preferably 0.04 kW or more, and is preferably 5 kW or less, more preferably 2 kW or less.
［１．２．易接着層］
　易接着層は、有機粒子（ＮＰ）を含み、好ましくは有機粒子（ＮＰ）に加えて重合体を含む。
　易接着層は、より好ましくは、易接着層材料の硬化物である。易接着層は、複層フィルムの製造において中間に製造されるフィルムの滑り性を向上させるために設けられる。易接着層材料は、有機粒子（ＮＰ）に加えて、好ましくは重合体（Ｐ１）と架橋剤（１）とを含む。 [1.2. Easy-adhesion layer]
The easy-adhesion layer contains organic particles (NP), and preferably contains a polymer in addition to the organic particles (NP).
The easy-adhesion layer is more preferably a cured product of the easy-adhesion layer material. The easy-adhesion layer is provided to improve the slipperiness of a film produced intermediately in the production of a multilayer film. In addition to the organic particles (NP), the material preferably comprises a polymer (P1) and a cross-linking agent (1).
　（易接着層材料：有機粒子（ＮＰ））
　（有機粒子の例）
　有機粒子は、粒子の屈折率調整を容易とし、粒度分布の広がりを狭くする観点から、有機重合体の粒子であることが好ましい。
　有機粒子の例としては、シリコーン重合体粒子、フッ素樹脂粒子、（メタ）アクリル重合体の粒子が挙げられる。
　有機重合体の粒子としては、重合体（Ｐ１）との親和性を高める観点から、（メタ）アクリル重合体の粒子が好ましい。
　（メタ）アクリル重合体とは、繰り返し単位として、（メタ）アクリル単量体単位を含む重合体である。（メタ）アクリル単量体単位は、（メタ）アクリル単量体を重合して得られうる構造を有する構成単位である。（メタ）アクリル単量体とは、（メタ）アクリル酸及び（メタ）アクリル酸の誘導体を意味する。（メタ）アクリル酸の誘導体の例としては、（メタ）アクリル酸エステル、（メタ）アクリルアミド、（メタ）アクリロニトリルが挙げられ、（メタ）アクリル酸エステルが好ましい。（メタ）アクリル酸エステルの例としては、アルキル（メタ）アクリレートが挙げられ、アルキル（メタ）アクリレートにおけるアルキル基は、ヒドロキシ基、ハロゲン原子などの置換基を有していてもよく、置換基を有していなくてもよい。 (Easy-adhesion layer material: organic particles (NP))
(Examples of organic particles)
The organic particles are preferably organic polymer particles, from the viewpoints of facilitating adjustment of the refractive index of the particles and narrowing the spread of the particle size distribution.
Examples of organic particles include silicone polymer particles, fluororesin particles, and (meth)acrylic polymer particles.
As the organic polymer particles, from the viewpoint of increasing the affinity with the polymer (P1), particles of a (meth)acrylic polymer are preferred.
The (meth)acrylic polymer is a polymer containing a (meth)acrylic monomer unit as a repeating unit. The (meth)acrylic monomer unit is a structural unit having a structure that can be obtained by polymerizing a (meth)acrylic monomer. The (meth)acrylic monomer means (meth)acrylic acid and a derivative of (meth)acrylic acid. Examples of the derivative of (meth)acrylic acid include (meth)acrylic acid esters, (meth)acrylamide, and (meth)acrylonitrile, and (meth)acrylic acid esters are preferred. Examples of (meth)acrylic acid esters include alkyl (meth)acrylates, and the alkyl group in the alkyl (meth)acrylate may or may not have a substituent such as a hydroxyl group or a halogen atom.
　（メタ）アクリル重合体は、（メタ）アクリル単量体単位に加えて、任意の単量体単位を含んでいてもよい。
　（メタ）アクリル重合体は、架橋性単量体単位を含む、架橋重合体であることが好ましい。架橋性単量体単位は、架橋性単量体を重合して得られうる単位である。架橋性単量体の例としては、一分子当たり二以上の重合性基を含む、多官能性単量体が挙げられ、具体的には、ジビニルベンゼン、エチレングリコールジ（メタ）アクリレート、ヘキサンジオールジ（メタ）アクリレート、ペンタエリスリトールトリアクリレート、トリメチロールプロパントリ（メタ）アクリレート、テトラメチロールメタンテトラアクリレート、ジアリルフタレート、トリアリルシアヌレートが挙げられる。架橋性単量体は、１種類単独で用いてもよく、２種類以上を任意の比率で組み合わせて用いてもよい。 The (meth)acrylic polymer may contain any monomer unit in addition to the (meth)acrylic monomer unit.
The (meth)acrylic polymer is preferably a crosslinked polymer containing a crosslinkable monomer unit. The crosslinkable monomer unit is a unit that can be obtained by polymerizing a crosslinkable monomer. Examples of the crosslinkable monomer include polyfunctional monomers containing two or more polymerizable groups per molecule, specifically, divinylbenzene, ethylene glycol di(meth)acrylate, hexanediol di(meth)acrylate, pentaerythritol triacrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tetraacrylate, diallyl phthalate, and triallyl cyanurate. The crosslinkable monomer may be used alone or in combination of two or more types at any ratio.
　（メタ）アクリル重合体の粒子として、（メタ）アクリル酸エステル単位を含む粒子が好ましく、メタクリル酸メチル単位及び架橋性単量体単位を含む、ポリメタクリル酸メチル系架橋重合体の粒子がより好ましい。 As the (meth)acrylic polymer particles, particles containing (meth)acrylic acid ester units are preferred, and particles of a polymethyl methacrylate-based crosslinked polymer containing methyl methacrylate units and crosslinkable monomer units are more preferred.
　有機粒子として、市販品を用いてもよい。市販品の例としては、日本触媒社製「エポスター（登録商標）ＭＸシリーズ」（ポリメタクリル酸メチル系架橋重合体の粒子）、綜研化学社製「ケミスノーＭＰシリーズ」（アクリル重合体粒子）、綜研化学社製「ケミスノーＭＸシリーズ」（スチレン－アクリル系樹脂粒子）、積水化成品工業社製「テクポリマー」が挙げられる。 Commercially available organic particles may be used. Examples of commercially available organic particles include Nippon Shokubai's "Eposter (registered trademark) MX Series" (particles of polymethyl methacrylate-based cross-linked polymer), Soken Chemical Industry's "Chemisnow MP Series" (acrylic polymer particles), Soken Chemical Industry's "Chemisnow MX Series" (styrene-acrylic resin particles), and Sekisui Chemical Industry's "Techpolymer."
　（有機粒子の平均粒子径）
　有機粒子の平均粒子径は、通常易接着層の厚みＴ１以上、好ましくは４５０ｎｍ未満、より好ましくは４００ｎｍ以下、更に好ましくは３５０ｎｍ以下である。有機粒子の平均粒子径が前記範囲内であると、易接着層から有機粒子が脱落しにくくなる。また、中間に製造される基材フィルムと易接着層との複層物の滑り性が向上する。 (Average particle size of organic particles)
The average particle diameter of the organic particles is usually equal to or larger than the thickness T1 of the easy-adhesion layer, preferably less than 450 nm, more preferably 400 nm or less, and even more preferably 350 nm or less. When the average particle diameter of the organic particles is within the above range, the organic particles are less likely to fall off from the easy-adhesion layer. In addition, the slipperiness of the laminate of the substrate film and the easy-adhesion layer produced in the middle is improved.
　（有機粒子の含有割合）
　有機粒子は、易接着層における含有割合が、好ましくは１重量％以上、より好ましくは１．２重量％以上、更に好ましくは１．５重量％以上であり、好ましくは５重量％以下、より好ましくは４．５重量％以下、更に好ましくは４重量％以下である。有機粒子の易接着層における含有割合は、易接着層の単位重量に含まれる有機粒子の重量割合である。易接着層における有機粒子の含有割合は、通常、易接着層を形成するための易接着層材料中の固形分合計量を１００重量％とした場合の、当該易接着材料に含まれる有機粒子の重量割合と一致する。 (Organic Particle Content)
The content of the organic particles in the easy-adhesion layer is preferably 1% by weight or more, more preferably 1.2% by weight or more, even more preferably 1.5% by weight or more, and preferably 5% by weight or less, more preferably 4.5% by weight or less, and even more preferably 4% by weight or less. The content of the organic particles in the easy-adhesion layer is the weight ratio of the organic particles contained in the unit weight of the easy-adhesion layer. The content of the organic particles in the easy-adhesion layer is usually the same as the weight ratio of the organic particles contained in the easy-adhesion material when the total amount of solids in the easy-adhesion layer material for forming the easy-adhesion layer is 100% by weight.
　（易接着層材料：重合体（Ｐ１））
　易接着層材料としては、重合体を含む各種の樹脂を用いうる。樹脂の例としては、ウレタン樹脂、オレフィン樹脂、ポリエステル樹脂、エポキシ樹脂及び（メタ）アクリル樹脂が挙げられる。これらの樹脂を用いて易接着層を形成することにより、易接着層と他の層との接着性に優れた複層フィルムを実現できる。 (Easy-Adhesion Layer Material: Polymer (P1))
As the material for the easy-adhesion layer, various resins including polymers can be used. Examples of resins include urethane resin, olefin resin, polyester resin, epoxy resin and (meth)acrylic resin. By forming the easy-adhesion layer using these resins, a multilayer film having excellent adhesion between the easy-adhesion layer and other layers can be realized.
　ウレタン樹脂としては、重合体（Ｐ１）としてポリウレタン又はその架橋物を含む樹脂を用いることができる。ポリウレタンとしては、例えば、各種のポリオール及びポリイソシアネートから誘導されるポリウレタンが挙げられる。ポリオールの例としては、ポリオール化合物と多塩基酸との反応により得られる脂肪族ポリエステルポリオール、ポリエーテルポリオール、ポリカーボネート系ポリオール、及びポリエチレンテレフタレートポリオールのいずれか一種；並びにこれらの混合物が挙げられる。前記のポリオール化合物としては、例えば、エチレングリコール、プロピレングリコール、１，４－ブタンジオール、ネオペンチルグリコール、グリセリン、トリメチロールプロパン等が挙げられる。前記の多塩基酸としては、例えば、ジカルボン酸およびトリカルボン酸を含む多価カルボン酸、またはその無水物等の、多価カルボン酸が挙げられる。ジカルボン酸としては、例えば、アジピン酸、コハク酸、セバシン酸、グルタル酸、マレイン酸、フマル酸、フタル酸、イソフタル酸、テレフタル酸等が挙げられる。トリカルボン酸としては、例えば、トリメリット酸等が挙げられる。前記のポリエーテルポリオールとしては、例えば、ポリ（オキシプロピレンエーテル）ポリオール、ポリ（オキシエチレン－プロピレンエーテル）ポリオール等が挙げられる。 As the urethane resin, a resin containing polyurethane or its crosslinked product as the polymer (P1) can be used. Examples of polyurethane include polyurethanes derived from various polyols and polyisocyanates. Examples of polyols include any one of aliphatic polyester polyols, polyether polyols, polycarbonate polyols, and polyethylene terephthalate polyols obtained by the reaction of a polyol compound with a polybasic acid; and mixtures thereof. Examples of the polyol compound include ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, glycerin, trimethylolpropane, and the like. Examples of the polybasic acid include polybasic carboxylic acids such as polybasic carboxylic acids including dicarboxylic acids and tricarboxylic acids, or anhydrides thereof. Examples of dicarboxylic acids include adipic acid, succinic acid, sebacic acid, glutaric acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, and the like. Examples of tricarboxylic acids include trimellitic acid, and the like. Examples of the polyether polyol include poly(oxypropylene ether) polyol and poly(oxyethylene-propylene ether) polyol.
　前記ポリウレタンでは、例えば、ポリオールとポリイソシアネートとの反応後、未反応として残った水酸基を架橋剤における官能基との架橋反応が可能な極性基として利用することができる。ポリウレタンとしては、ポリカーボネート系ポリオール及びポリイソシアネートから誘導され、その骨格にカーボネート構造を含むポリカーボネート系のポリウレタンが好ましい。ウレタン樹脂については、例えば、特開２０１６－１８２５６８号公報の記載を参照しうる。 In the polyurethane, for example, after the reaction between polyol and polyisocyanate, the unreacted hydroxyl groups remaining can be used as polar groups capable of crosslinking with the functional groups in the crosslinking agent. As the polyurethane, a polycarbonate-based polyurethane derived from a polycarbonate-based polyol and polyisocyanate and containing a carbonate structure in its skeleton is preferred. For details of the urethane resin, the description in JP 2016-182568 A can be referred to, for example.
　ポリウレタンとしては、水系ウレタン樹脂として市販されている水系エマルションに含まれるものを用いてもよい。水系ウレタン樹脂とは、ポリウレタンと水とを含む組成物であり、通常、ポリウレタンおよび必要に応じて含まれる任意成分が水の中に分散しているものである。水系ウレタン樹脂の例としては、ＡＤＥＫＡ社製の「アデカボンタイター」シリーズ、三井化学社製の「オレスター」シリーズ、ＤＩＣ社製の「ボンディック」シリーズ、「ハイドラン（ＷＬＳ２０１，ＷＬＳ２０２など）」シリーズ、バイエル社製の「インプラニール」シリーズ、花王社製の「ポイズ」シリーズ、三洋化成工業社製の「サンプレン」シリーズ、第一工業製薬社製の「スーパーフレックス」シリーズ、楠本化成社製の「ＮＥＯＲＥＺ（ネオレッズ）」シリーズ、ルーブリゾール社製の「Ｓａｎｃｕｒｅ」シリーズなどを用いることができる。 As the polyurethane, those contained in water-based emulsions commercially available as water-based urethane resins may be used. Water-based urethane resins are compositions containing polyurethane and water, and usually polyurethane and optional components contained as necessary are dispersed in water. Examples of water-based urethane resins that can be used include the "ADEKA BONTITOR" series manufactured by ADEKA Corporation, the "OLESTAR" series manufactured by Mitsui Chemicals, Inc., the "BONDIC" series manufactured by DIC Corporation, the "HYDRAN (WLS201, WLS202, etc.)" series manufactured by Bayer, the "POISE" series manufactured by Kao Corporation, the "SANPRENE" series manufactured by Sanyo Chemical Industries, Ltd., the "SUPERFLEX" series manufactured by Daiichi Kogyo Seiyaku Co., Ltd., the "NEOREZ" series manufactured by Kusumoto Chemicals, Inc., and the "SANCURE" series manufactured by Lubrizol Corporation.
　オレフィン樹脂としては、重合体（Ｐ１）として、不飽和カルボン酸成分の含有量が０．１重量％～１０重量％である酸変性ポリオレフィン又はその架橋物を含む樹脂を用いることができる。酸変性ポリオレフィンの主成分であるオレフィン成分の好ましい例としては、エチレン、プロピレン、イソブチレン、２－ブテン、１－ブテン、１－ペンテン、１－ヘキセンなどの炭素数２～６のアルケン、及びこれらの混合物が挙げられる。中でも、樹脂層の密着性を高める観点から、エチレン、プロピレン、イソブチレン、１－ブテンなどの炭素数２～４のアルケンがより好ましく、エチレン、プロピレンがさらに好ましく、エチレンが特に好ましい。他方、酸変性ポリオレフィンの変性成分である不飽和カルボン酸成分としては、例えば、アクリル酸、メタクリル酸、（無水）マレイン酸、（無水）イタコン酸、フマル酸、クロトン酸、不飽和ジカルボン酸のハーフエステル、ハーフアミドなどが挙げられる。中でも、樹脂で形成された層（以下、樹脂層ともいう。）の密着性を高めたりひび割れを抑制したりできるので、アクリル酸、メタクリル酸、（無水）マレイン酸が好ましく、アクリル酸、（無水）マレイン酸が特に好ましい。前記の不飽和カルボン酸成分は、通常、酸変性ポリオレフィン中で共重合されており、その形態は特に限定されない。共重合の状態としては、例えば、ランダム共重合、ブロック共重合、グラフト共重合（グラフト変性）などが挙げられる。オレフィン樹脂については、例えば、特開２０１４－２４０１７４号公報の記載を参照しうる。 As the olefin resin, a resin containing an acid-modified polyolefin or its crosslinked product having an unsaturated carboxylic acid component content of 0.1% by weight to 10% by weight as the polymer (P1) can be used. Preferred examples of the olefin component that is the main component of the acid-modified polyolefin include alkenes having 2 to 6 carbon atoms, such as ethylene, propylene, isobutylene, 2-butene, 1-butene, 1-pentene, and 1-hexene, and mixtures thereof. Among them, from the viewpoint of increasing the adhesion of the resin layer, alkenes having 2 to 4 carbon atoms, such as ethylene, propylene, isobutylene, and 1-butene, are more preferred, ethylene and propylene are even more preferred, and ethylene is particularly preferred. On the other hand, examples of the unsaturated carboxylic acid component that is the modified component of the acid-modified polyolefin include acrylic acid, methacrylic acid, maleic acid (anhydride), itaconic acid (anhydride), fumaric acid, crotonic acid, half esters of unsaturated dicarboxylic acids, and half amides. Among these, acrylic acid, methacrylic acid, and maleic acid (anhydride) are preferred, and acrylic acid and maleic acid (anhydride) are particularly preferred, since they can increase the adhesion of the layer formed of the resin (hereinafter also referred to as the resin layer) and suppress cracking. The unsaturated carboxylic acid component is usually copolymerized in the acid-modified polyolefin, and the form is not particularly limited. Examples of the copolymerization state include random copolymerization, block copolymerization, and graft copolymerization (graft modification). For details of the olefin resin, the description in JP-A-2014-240174 can be referred to, for example.
　酸変性ポリオレフィンとしては、市販品を用いてもよい。その水性分散体の該市販品としては、例えば、「アローベース（アローベースＳＡ－１２００、アローベースＳＢ－１２００、アローベースＳＥ－１２００、アローベースＳＢ－１０１０）」シリーズ（ユニチカ社製）などが挙げられる。 As the acid-modified polyolefin, commercially available products may be used. Examples of commercially available aqueous dispersions include the "Arrowbase (Arrowbase SA-1200, Arrowbase SB-1200, Arrowbase SE-1200, Arrowbase SB-1010)" series (manufactured by Unitika Ltd.).
　ポリエステル樹脂としては、重合体（Ｐ１）として、前記ポリオール化合物と前記多塩基酸との反応により得られるポリエステル又はその架橋物を含む樹脂を用いることができる。このポリエステルでは、例えば、ポリオール化合物と多塩基酸との反応終了後、未反応として残った水酸基及びカルボキシル基を架橋剤との架橋反応が可能な極性基として利用することができる。また、ポリエステルは、前記のポリオール化合物及び多塩基酸に組み合わせて、水酸基、カルボキシル基等の極性基を有する共重合成分を共重合したものであってもよい。また、ポリエステル樹脂は、樹脂層の密着性の向上のため、ポリエステル又はその架橋物に組み合わせて、更にアクリルポリマーを含むことが好ましい。ポリエステル樹脂については、例えば、特開２０１５－０２４５１１号公報の記載を参照しうる。 As the polyester resin, a resin containing a polyester or its crosslinked product obtained by the reaction of the polyol compound with the polybasic acid can be used as the polymer (P1). In this polyester, for example, after the reaction between the polyol compound and the polybasic acid is completed, the unreacted hydroxyl group and carboxyl group remaining can be used as a polar group capable of crosslinking with a crosslinking agent. The polyester may also be a copolymer of the polyol compound and the polybasic acid with a copolymer component having a polar group such as a hydroxyl group or a carboxyl group. In addition, the polyester resin preferably further contains an acrylic polymer in combination with the polyester or its crosslinked product in order to improve the adhesion of the resin layer. For polyester resins, for example, the description in JP 2015-024511 A may be referred to.
　ポリエステルとしては、市販品を用いてもよい。水溶性又は水分散のポリエステルの市販品としては、例えば、「ニチゴポリエスター（ニチゴポリエスターＷ－００３０、ニチゴポリエスターＷ－０００５Ｓ３０ＷＯ、ニチゴポリエスターＷＲ－９６１等）」シリーズ（日本合成化学社製）、「ペスレジンＡ（ペスレジンＡ－２１０、ペスレジンＡ－５２０、ペスレジンＡ－６８４Ｇ、ペスレジンＡ－６９５ＧＥ等）」シリーズ（高松油脂社製）などが挙げられる。 As the polyester, commercially available products may be used. Examples of commercially available water-soluble or water-dispersible polyester products include the "Nichigo Polyester (Nichigo Polyester W-0030, Nichigo Polyester W-0005S30WO, Nichigo Polyester WR-961, etc.)" series (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) and the "PES Resin A (PES Resin A-210, PES Resin A-520, PES Resin A-684G, PES Resin A-695GE, etc.)" series (manufactured by Takamatsu Oil Co., Ltd.).
　エポキシ樹脂としては、一液硬化型のエポキシ樹脂、二液硬化型のエポキシ樹脂等、任意のエポキシ樹脂を用いることができる。中でも、重合体（Ｐ１）として水溶性のエポキシポリマーを含むものが好ましい。水溶性のエポキシポリマーの好ましい例としては、ポリアミドエポキシポリマーが挙げられる。このポリアミドエポキシポリマーは、例えば、ジエチレントリアミン、トリエチレンテトラミン等のポリアルキレンポリアミンと、アジピン酸等のジカルボン酸との反応で得られるポリアミドポリアミンに、エピクロロヒドリンを反応させて得られる。このようなポリアミドエポキシポリマーの市販品としては、例えば、住化ケムテック社製の「スミレーズレジン　６５０（３０）」、「スミレーズレジン　６７５」が挙げられる。エポキシ樹脂については、例えば、特開２００８－２６３５２号公報の記載を参照しうる。 As the epoxy resin, any epoxy resin can be used, such as a one-component curing type epoxy resin or a two-component curing type epoxy resin. Among them, those containing a water-soluble epoxy polymer as the polymer (P1) are preferable. A preferable example of a water-soluble epoxy polymer is polyamide epoxy polymer. This polyamide epoxy polymer is obtained by reacting epichlorohydrin with polyamide polyamine obtained by reacting polyalkylene polyamine such as diethylenetriamine or triethylenetetramine with dicarboxylic acid such as adipic acid. Commercially available products of such polyamide epoxy polymers include "Sumirez Resin 650 (30)" and "Sumirez Resin 675" manufactured by Sumika Chemtech Co., Ltd. For details of epoxy resins, see, for example, JP 2008-26352 A.
　水溶性のエポキシポリマーを用いる場合は、さらに塗工性を向上させるために、ポリビニルアルコールなどの水溶性ポリマーを組み合わせて用いることが好ましい。このポリビニルアルコールには、部分ケン化ポリビニルアルコール、完全ケン化ポリビニルアルコールだけでなく、カルボキシル基変性ポリビニルアルコール、アセトアセチル基変性ポリビニルアルコール、メチロール基変性ポリビニルアルコール、アミノ基変性ポリビニルアルコール等の、変性ポリビニルアルコールが含まれる。ポリビニルアルコールの市販品としては、クラレ社製のアニオン性基含有ポリビニルアルコールである「ＫＬ－３１８」が挙げられる。 When using a water-soluble epoxy polymer, it is preferable to use it in combination with a water-soluble polymer such as polyvinyl alcohol to further improve the coating properties. This polyvinyl alcohol includes not only partially saponified polyvinyl alcohol and fully saponified polyvinyl alcohol, but also modified polyvinyl alcohols such as carboxyl group-modified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, methylol group-modified polyvinyl alcohol, and amino group-modified polyvinyl alcohol. An example of a commercially available polyvinyl alcohol is "KL-318," an anionic group-containing polyvinyl alcohol manufactured by Kuraray Co., Ltd.
　（メタ）アクリル樹脂としては、重合体（Ｐ１）として、（メタ）アクリルポリマー又はその架橋物を含む樹脂を用いることができる。また、（メタ）アクリルポリマーとしては、例えば、（メタ）アクリルモノマーの単独重合体、２種類以上の（メタ）アクリルモノマーの共重合体、１種類以上の（メタ）アクリルモノマーと他のモノマーとの共重合体、などが挙げられる。また、（メタ）アクリルモノマーとしては、例えば、アクリル酸、アクリル酸アルキル等のアクリル酸エステル、アクリルアミド、アクリロニトリル、メタクリル酸、メタクリル酸アルキル等のメタクリル酸エステル、メタクリルアミド及びメタクリロニトリル等が挙げられる。 As the (meth)acrylic resin, a resin containing a (meth)acrylic polymer or a crosslinked product thereof can be used as the polymer (P1). In addition, examples of the (meth)acrylic polymer include a homopolymer of a (meth)acrylic monomer, a copolymer of two or more types of (meth)acrylic monomers, and a copolymer of one or more types of (meth)acrylic monomers with other monomers. In addition, examples of the (meth)acrylic monomer include acrylic acid, acrylic acid esters such as alkyl acrylates, acrylamide, acrylonitrile, methacrylic acid, methacrylic acid esters such as alkyl methacrylates, methacrylamide, and methacrylonitrile.
　中でも、重合体（Ｐ１）として、（メタ）アクリル酸エステル単位を有する重合体が好ましく、アクリル酸エステル及びメタクリル酸エステルからなる群より選ばれるアクリルモノマーの単独重合体及び共重合体がより好ましい。特に好ましい例としては、炭素原子数１～６のアルキル基を有するアクリル酸エステル及びメタクリル酸エステルからなる群より選ばれるアクリルモノマーの単独重合体及び共重合体が挙げられる。また、アクリルポリマーは、架橋剤が有する官能基との反応（架橋反応）が可能なように、前記のアクリルモノマーに組み合わせて、水酸基、カルボキシル基等の極性基を有する共重合成分を共重合したものが好ましい。アクリル樹脂については、例えば、特開２０１５－０２４５１１号公報の記載を参照しうる。 Among them, as the polymer (P1), a polymer having a (meth)acrylic acid ester unit is preferable, and a homopolymer or copolymer of an acrylic monomer selected from the group consisting of an acrylic acid ester and a methacrylic acid ester is more preferable. Particularly preferable examples include a homopolymer or copolymer of an acrylic monomer selected from the group consisting of an acrylic acid ester and a methacrylic acid ester having an alkyl group having 1 to 6 carbon atoms. In addition, the acrylic polymer is preferably a copolymer of a copolymerization component having a polar group such as a hydroxyl group or a carboxyl group in combination with the acrylic monomer so as to be capable of reacting (crosslinking reaction) with the functional group of the crosslinking agent. For acrylic resins, for example, the description in JP 2015-024511 A may be referred to.
　重合体（Ｐ１）が（メタ）アクリル酸エステル単位を有する場合、重合体（Ｐ１）における（メタ）アクリル酸エステル単位の重量割合は、重合体（Ｐ１）に含まれる単量体単位の合計を１００重量％として、好ましくは１重量％以上、より好ましくは５重量％以上、更に好ましくは１０重量％以上であり、通常１００重量％以下である。 When the polymer (P1) has (meth)acrylic acid ester units, the weight proportion of the (meth)acrylic acid ester units in the polymer (P1) is preferably 1% by weight or more, more preferably 5% by weight or more, and even more preferably 10% by weight or more, and is usually 100% by weight or less, assuming that the total of the monomer units contained in the polymer (P1) is 100% by weight.
　易接着層材料が（メタ）アクリル樹脂である場合、易接着層材料に含まれる重合体（Ｐ１）としては、メタクリル酸のアルキルエステルとアクリル酸のアルキルエステルとの共重合体が好ましい。この場合アルキルエステルを構成するアルキル基の炭素原子数は１～６であることが好ましく、１～４であることが特に好ましい。より具体的な例として、重合体（Ｐ１）は、メチルメタクリレート及びブチルアクリレートの共重合体であることが特に好ましい。このような好ましい重合体（Ｐ１）を採用することにより、易接着層とアンカー層との密着性に優れるため、特に好ましい。 When the easy-adhesion layer material is a (meth)acrylic resin, the polymer (P1) contained in the easy-adhesion layer material is preferably a copolymer of an alkyl ester of methacrylic acid and an alkyl ester of acrylic acid. In this case, the number of carbon atoms in the alkyl group constituting the alkyl ester is preferably 1 to 6, and particularly preferably 1 to 4. As a more specific example, it is particularly preferable that the polymer (P1) is a copolymer of methyl methacrylate and butyl acrylate. By employing such a preferred polymer (P1), excellent adhesion between the easy-adhesion layer and the anchor layer is achieved, which is particularly preferable.
　易接着層材料を構成する重合体（Ｐ１）は、１種類でもよく、２種類以上でもよい。よって、易接着層材料は、上述したポリウレタン、ポリオレフィン、ポリエステル、エポキシ重合体及び（メタ）アクリル重合体のうちの２種類以上を組み合わせて含む複合樹脂であってもよい。例えば、ポリウレタンと酸変性ポリオレフィンとを組み合わせて含む樹脂、又はポリエステルとアクリルポリマーとを組み合わせて含む樹脂であってもよい。 The polymer (P1) constituting the easy-adhesion layer material may be one type, or two or more types. Therefore, the easy-adhesion layer material may be a composite resin containing two or more types of the above-mentioned polyurethane, polyolefin, polyester, epoxy polymer, and (meth)acrylic polymer in combination. For example, it may be a resin containing a combination of polyurethane and acid-modified polyolefin, or a resin containing a combination of polyester and acrylic polymer.
　易接着層材料の固形分（溶媒以外の成分の全量）における重合体（Ｐ１）の割合は、好ましくは５０重量％～９９重量％、より好ましくは７０重量％～９９重量％、特に好ましくは９０重量％～９７重量％である。重合体（Ｐ１）の割合が前記範囲にある場合、得られる易接着層が所望の密着性を発現できる。 The proportion of polymer (P1) in the solid content (total amount of components other than the solvent) of the easy-adhesion layer material is preferably 50% by weight to 99% by weight, more preferably 70% by weight to 99% by weight, and particularly preferably 90% by weight to 97% by weight. When the proportion of polymer (P1) is within the above range, the resulting easy-adhesion layer can exhibit the desired adhesion.
　（易接着層材料：架橋剤（１））
　易接着層材料が架橋剤（１）を含むことにより、易接着層材料の硬化物である易接着層は、架橋構造を有する重合体を含む層となり得る。架橋剤（１）としては、重合体が含む極性基等の官能基と反応して結合を形成できる官能基を分子内に２個以上有する化合物、当該化合物を含む単量体組成物が重合することにより、結合を形成できる官能基を有する重合体となった重合体架橋剤、又はこれらの混合物を用いることができる。架橋剤化合物（重合体架橋剤を構成する単量体を含む）の例としては、エポキシ化合物、カルボジイミド化合物、オキサゾリン化合物、イソシアネート化合物等が挙げられる。また、架橋剤化合物は、１種類を単独で用いてもよく、２種類以上を任意の比率で組み合わせて用いてもよい。 (Easy-Adhesion Layer Material: Crosslinking Agent (1))
By including the crosslinking agent (1) in the easy-adhesion layer material, the easy-adhesion layer, which is a cured product of the easy-adhesion layer material, can be a layer containing a polymer having a crosslinked structure. As the crosslinking agent (1), a compound having two or more functional groups in the molecule capable of reacting with a functional group such as a polar group contained in the polymer to form a bond, a polymer crosslinking agent in which a monomer composition containing the compound is polymerized to form a polymer having a functional group capable of forming a bond, or a mixture thereof can be used. Examples of the crosslinking agent compound (including the monomer constituting the polymer crosslinking agent) include an epoxy compound, a carbodiimide compound, an oxazoline compound, an isocyanate compound, and the like. In addition, the crosslinking agent compound may be used alone or in combination of two or more types in any ratio.
　エポキシ化合物としては、分子内に２個以上のエポキシ基を有する多官能のエポキシ化合物を用いることができる。これにより、架橋反応を進行させて樹脂層の機械的強度を効果的に向上させることができる。 As the epoxy compound, a multifunctional epoxy compound having two or more epoxy groups in the molecule can be used. This allows the crosslinking reaction to proceed, effectively improving the mechanical strength of the resin layer.
　エポキシ化合物としては、水に溶解性があるか、または水に分散してエマルション化しうるものが、使用の容易性の観点から好ましい。エポキシ化合物の例を挙げると、エチレングリコール、ジエチレングリコール、トリエチレングリコール、ポリエチレングリコール、プロピレングリコール、ジプロピレングリコール、１，４－ブタンジオール、１，６－ヘキシレングリコール、ネオペンチルグリコール等のグリコール類１モルと、エピクロルヒドリン２モルとのエーテル化によって得られるジエポキシ化合物；グリセリン、ポリグリセリン、トリメチロールプロパン、ペンタエリスリトール、ソルビトール等の多価アルコール類１モルと、エピクロルヒドリン２モル以上とのエーテル化によって得られるポリエポキシ化合物；フタル酸、テレフタル酸、シュウ酸、アジピン酸等のジカルボン酸１モルと、エピクロルヒドリン２モルとのエステル化によって得られるジエポキシ化合物；などが挙げられる。 As epoxy compounds, those that are soluble in water or can be dispersed in water to form an emulsion are preferred from the viewpoint of ease of use. Examples of epoxy compounds include diepoxy compounds obtained by etherifying 1 mole of glycols such as ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, 1,6-hexylene glycol, and neopentyl glycol with 2 moles of epichlorohydrin; polyepoxy compounds obtained by etherifying 1 mole of polyhydric alcohols such as glycerin, polyglycerin, trimethylolpropane, pentaerythritol, and sorbitol with 2 moles or more of epichlorohydrin; diepoxy compounds obtained by esterifying 1 mole of dicarboxylic acid such as phthalic acid, terephthalic acid, oxalic acid, and adipic acid with 2 moles of epichlorohydrin; and the like.
　より具体的に、エポキシ化合物としては、１，４－ビス（２’，３’－エポキシプロピルオキシ）ブタン、１，３，５－トリグリシジルイソシアヌレート、１，３－ジグリシジル－５－（γ－アセトキシ－β－オキシプロピル）イソシアヌレート、ソルビトールポリグリシジルエーテル類、ポリグリセロールポリグリシジルエーテル類、ペンタエリスリトールポリグリシジルエーテル類、ジグリセロールポリグリシジルエーテル、グリセロールポリグリシジルエーテル類およびトリメチロールプロパンポリグリシジルエーテル類等のエポキシ化合物が好ましい。その具体的な市販品の例としては、ナガセケムテックス社製の「デナコール（デナコールＥＸ－５２１，ＥＸ－６１４Ｂなど）」シリーズ等を挙げることができる。 More specifically, preferred epoxy compounds include 1,4-bis(2',3'-epoxypropyloxy)butane, 1,3,5-triglycidyl isocyanurate, 1,3-diglycidyl-5-(γ-acetoxy-β-oxypropyl)isocyanurate, sorbitol polyglycidyl ethers, polyglycerol polyglycidyl ethers, pentaerythritol polyglycidyl ethers, diglycerol polyglycidyl ethers, glycerol polyglycidyl ethers, and trimethylolpropane polyglycidyl ethers. Specific examples of commercially available products include the "Denacol (Denacol EX-521, EX-614B, etc.)" series manufactured by Nagase ChemteX Corporation.
　オキサゾリン化合物としては、付加重合性オキサゾリン化合物を用いうる。その具体例としては、２－ビニル－２－オキサゾリン、２－ビニル－４－メチル－２－オキサゾリン、２－ビニル－５－メチル－２－オキサゾリン、２－イソプロペニル－２－オキサゾリン、２－イソプロペニル－４－メチル－２－オキサゾリン、２－イソプロペニル－５－エチル－２－オキサゾリン等が挙げられる。また、これらは１種類を単独で用いてもよく、２種類以上を任意の比率で組み合わせて用いてもよい。これらの中でも、２－イソプロペニル－２－オキサゾリンが、工業的にも入手し易く好適である。 As the oxazoline compound, an addition-polymerizable oxazoline compound can be used. Specific examples include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, and 2-isopropenyl-5-ethyl-2-oxazoline. These compounds may be used alone or in combination of two or more at any ratio. Among these, 2-isopropenyl-2-oxazoline is preferred because it is easily available industrially.
　架橋剤（１）が重合体架橋剤である場合、特に、付加重合性オキサゾリン化合物と、任意の不飽和単量体との重合体である架橋剤（１－ｏ）が好ましい。架橋剤（１－ｏ）を構成する、オキサゾリン化合物以外の任意の不飽和単量体としては、付加重合性オキサゾリンと共重合可能であり、かつ、オキサゾリン基と反応しない任意の単量体を用いうる。このような任意の不飽和単量体は、上述した単量体から任意に選択して用いうる。かかる不飽和単量体の好ましい具体例としては、メチルメタクリレート等のメタクリル酸エステルが挙げられる。そして、架橋剤（１－ｏ）としては、２－イソプロペニル－２－オキサゾリンとメタクリル酸エステルとの共重合体が、良好な密着性等の所望の効果を発現する上で特に好ましい。 When the crosslinking agent (1) is a polymeric crosslinking agent, a crosslinking agent (1-o) that is a polymer of an addition-polymerizable oxazoline compound and an arbitrary unsaturated monomer is particularly preferred. As the arbitrary unsaturated monomer other than the oxazoline compound that constitutes the crosslinking agent (1-o), any monomer that is copolymerizable with the addition-polymerizable oxazoline and does not react with the oxazoline group can be used. Such an arbitrary unsaturated monomer can be arbitrarily selected from the monomers described above. A specific example of a preferred unsaturated monomer is a methacrylic acid ester such as methyl methacrylate. As the crosslinking agent (1-o), a copolymer of 2-isopropenyl-2-oxazoline and a methacrylic acid ester is particularly preferred in terms of achieving the desired effects such as good adhesion.
　架橋剤（１－ｏ）の製造において用いる付加重合性オキサゾリンの量は、オキサゾリン化合物の製造に用いる全単量体成分１００重量部に対して、好ましくは５重量部以上である。 The amount of addition-polymerizable oxazoline used in the production of the crosslinking agent (1-o) is preferably 5 parts by weight or more per 100 parts by weight of the total monomer components used in the production of the oxazoline compound.
　架橋剤（１－ｏ）としては、市販品として入手可能なものを利用しうる。架橋剤（１－ｏ）のうち、水溶性タイプのものの例としては、日本触媒社製のエポクロスＷＳ－５００及びＷＳ－７００が挙げられる。また、例えばエマルションタイプのものの例としては、日本触媒社製のエポクロスＫ－２０１０、Ｋ－２０２０及びＫ－２０３０が挙げられる。 Crossing agents (1-o) that are commercially available can be used. Examples of water-soluble crosslinking agents (1-o) include Epocross WS-500 and WS-700 manufactured by Nippon Shokubai Co., Ltd. Examples of emulsion-type crosslinking agents (1-o) include Epocross K-2010, K-2020, and K-2030 manufactured by Nippon Shokubai Co., Ltd.
　架橋剤（１－ｏ）及びその他のもの等の架橋剤（１）は、１種類を単独で用いてもよく、２種類以上を任意の比率で組み合わせて用いてもよい。 Crosslinking agent (1-o) and other crosslinking agents (1) may be used alone or in combination of two or more in any ratio.
　易接着層における、重合体（Ｐ１）に対する架橋剤（１）の割合は、所望の密着性及びその他の効果が発現される範囲に適宜調整しうる。具体的には、重合体（Ｐ１）及び架橋剤（１）の合計１００重量部に対する架橋剤（１）の割合は、好ましくは１重量部以上、より好ましくは３重量部以上であり、一方好ましくは３０重量部以下、より好ましくは２０重量部以下としうる。 The ratio of the crosslinking agent (1) to the polymer (P1) in the easy-adhesion layer can be adjusted appropriately to a range in which the desired adhesion and other effects are achieved. Specifically, the ratio of the crosslinking agent (1) to a total of 100 parts by weight of the polymer (P1) and the crosslinking agent (1) is preferably 1 part by weight or more, more preferably 3 parts by weight or more, while it is preferably 30 parts by weight or less, more preferably 20 parts by weight or less.
　（易接着層材料：溶媒）
　易接着層材料は、溶媒を含みうる。溶媒を含むことにより、易接着層材料を液状の組成物とすることができ、塗布等の、易接着層の形成の操作を容易にすることができる。溶媒としては、水、有機溶媒、又はこれらの混合物を適宜選択しうる。有機溶媒の例としては、酢酸メチル、酢酸エチル、アセトン、メチルエチルケトン、３－メチル－２－ブタノン、メチルイソプロピルケトン、メチルイソブチルケトン、テトラヒドロフラン、シクロペンチルメチルエーテル、アセチルアセトン、シクロヘキサノン、２－メチルシクロヘキサノン、１，３－ジオキソラン、１，４－ジオキサン、２－ペンタノン、Ｎ，Ｎ－ジメチルホルムアミドなどが挙げられる。また、溶媒は、１種類を単独で用いてもよく、２種類以上を任意の比率で組み合わせて用いてもよい。良好な揮発性の高さ及び他の成分を溶解する能力の高さから、水を、溶媒として好ましく用いうる。 (Easy-adhesion layer material: solvent)
The easy-adhesion layer material may contain a solvent. By containing a solvent, the easy-adhesion layer material can be made into a liquid composition, and the operation of forming the easy-adhesion layer, such as coating, can be facilitated. As the solvent, water, an organic solvent, or a mixture thereof can be appropriately selected. Examples of organic solvents include methyl acetate, ethyl acetate, acetone, methyl ethyl ketone, 3-methyl-2-butanone, methyl isopropyl ketone, methyl isobutyl ketone, tetrahydrofuran, cyclopentyl methyl ether, acetylacetone, cyclohexanone, 2-methylcyclohexanone, 1,3-dioxolane, 1,4-dioxane, 2-pentanone, and N,N-dimethylformamide. In addition, the solvent may be used alone or in combination of two or more kinds in any ratio. Water can be preferably used as the solvent because of its good volatility and high ability to dissolve other components.
　易接着層材料に含まれる溶媒の割合は、塗布等の、易接着層の形成の操作に適した物性が得られるよう適宜調整しうる。具体的には、固形分濃度（溶媒以外の、有機粒子（ＮＰ）を含む成分の割合）が好ましくは１重量％～２０重量％、より好ましくは２重量％～１０重量％となるよう割合を調整しうる。 The proportion of the solvent contained in the easy-adhesion layer material can be adjusted as appropriate to obtain physical properties suitable for the operation of forming the easy-adhesion layer, such as coating. Specifically, the proportion can be adjusted so that the solids concentration (proportion of components other than the solvent, including organic particles (NP)) is preferably 1% by weight to 20% by weight, more preferably 2% by weight to 10% by weight.
　（易接着層材料：その他の成分）
　易接着層材料は、更に任意の成分を含みうる。任意の成分の例としては、硬化促進剤、硬化助剤、有機粒子（ＮＰ）以外の粒子、耐熱安定剤、耐候安定剤、レベリング剤、界面活性剤、酸化防止剤、帯電防止剤、スリップ剤、アンチブロッキング剤、防曇剤、滑剤、染料、顔料、天然油、合成油、ワックスなどが挙げられる。 (Easy-adhesion layer material: other components)
The easy-adhesion layer material may further include any optional components, such as a curing accelerator, a curing assistant, particles other than organic particles (NPs), a heat stabilizer, a weather stabilizer, a leveling agent, a surfactant, an antioxidant, an antistatic agent, a slip agent, an antiblocking agent, an antifogging agent, a lubricant, a dye, a pigment, a natural oil, a synthetic oil, and a wax.
［１．３．アンカー層］
　アンカー層は、好ましくは、アンカー層材料の硬化物である。アンカー層は、基材フィルムとトップ層との密着性を高めるために設けられる。アンカー層材料は、重合体（Ｐ２）及び架橋剤（２）を含む。 [1.3. Anchor layer]
The anchor layer is preferably a cured product of the anchor layer material. The anchor layer is provided to enhance adhesion between the base film and the top layer. The anchor layer material includes a polymer (P2) and a crosslinking agent (2).
　（アンカー層材料：重合体（Ｐ２））
　アンカー層材料としては、重合体を含む各種の樹脂を用いうる。樹脂の例としては、易接着層材料に含まれうる樹脂の例と同様の例が挙げられる。
　アンカー層材料に含まれる重合体（Ｐ２）としては、（メタ）アクリル酸エステル単位を有する重合体が好ましい。中でも、重合体（Ｐ２）として、（メタ）アクリル酸エステル単位を有する重合体が好ましく、アクリル酸エステル及びメタクリル酸エステルからなる群より選ばれるアクリルモノマーの単独重合体及び共重合体がより好ましい。特に好ましい例としては、炭素原子数１～６のアルキル基を有するアクリル酸エステル及びメタクリル酸エステルからなる群より選ばれるアクリルモノマーの単独重合体及び共重合体が挙げられる。また、アクリルポリマーは、架橋剤が有する官能基との反応（架橋反応）が可能なように、前記のアクリルモノマーに組み合わせて、水酸基、カルボキシル基等の極性基を有する共重合成分を共重合したものが好ましい。 (Anchor layer material: polymer (P2))
As the anchor layer material, various resins including polymers can be used. Examples of the resin include the same examples as those of the resin that can be contained in the easy-adhesion layer material.
The polymer (P2) contained in the anchor layer material is preferably a polymer having a (meth)acrylic acid ester unit. Among them, the polymer (P2) is preferably a polymer having a (meth)acrylic acid ester unit, and more preferably a homopolymer or copolymer of an acrylic monomer selected from the group consisting of acrylic acid esters and methacrylic acid esters. Particularly preferred examples include homopolymers and copolymers of acrylic monomers selected from the group consisting of acrylic acid esters and methacrylic acid esters having an alkyl group having 1 to 6 carbon atoms. In addition, the acrylic polymer is preferably a copolymer of a copolymerization component having a polar group such as a hydroxyl group or a carboxyl group in combination with the acrylic monomer so as to be capable of reacting (crosslinking reaction) with the functional group of the crosslinking agent.
　重合体（Ｐ２）が（メタ）アクリル酸エステル単位を有する場合、重合体（Ｐ２）における（メタ）アクリル酸エステル単位の重量割合は、重合体（Ｐ１）が（メタ）アクリル酸エステル単位を有する場合の重合体（Ｐ１）における（メタ）アクリル酸エステル単位の重量割合と同様の範囲としうる。 When the polymer (P2) has (meth)acrylic acid ester units, the weight proportion of the (meth)acrylic acid ester units in the polymer (P2) may be in the same range as the weight proportion of the (meth)acrylic acid ester units in the polymer (P1) when the polymer (P1) has (meth)acrylic acid ester units.
　アンカー層材料が（メタ）アクリル樹脂である場合、アンカー層材料に含まれる重合体（Ｐ２）としては、メタクリル酸のアルキルエステルとアクリル酸のアルキルエステルとの共重合体が好ましい。この場合アルキルエステルを構成するアルキル基の炭素原子数は１～６であることが好ましく、１～４であることが特に好ましい。より具体的な例として、重合体（Ｐ２）は、メチルメタクリレート及びブチルアクリレートの共重合体であることが特に好ましい。このような好ましい重合体（Ｐ２）を採用することにより、アンカー層と易接着層及びトップ層との密着性に優れるため、特に好ましい。 When the anchor layer material is a (meth)acrylic resin, the polymer (P2) contained in the anchor layer material is preferably a copolymer of an alkyl ester of methacrylic acid and an alkyl ester of acrylic acid. In this case, the number of carbon atoms in the alkyl group constituting the alkyl ester is preferably 1 to 6, and particularly preferably 1 to 4. As a more specific example, it is particularly preferable that the polymer (P2) is a copolymer of methyl methacrylate and butyl acrylate. By adopting such a preferred polymer (P2), excellent adhesion between the anchor layer and the easy-adhesion layer and the top layer is achieved, which is particularly preferable.
　アンカー層材料の固形分（溶媒以外の成分の全量）における重合体（Ｐ２）の割合は、好ましくは５０重量％～９９重量％、より好ましくは７０重量％～９９重量％、特に好ましくは９０重量％～９９重量％である。重合体（Ｐ２）の割合が前記範囲にある場合、得られるアンカー層が所望の密着性を発現できる。 The proportion of polymer (P2) in the solid content (total amount of components other than the solvent) of the anchor layer material is preferably 50% by weight to 99% by weight, more preferably 70% by weight to 99% by weight, and particularly preferably 90% by weight to 99% by weight. When the proportion of polymer (P2) is within the above range, the resulting anchor layer can exhibit the desired adhesion.
　（アンカー層材料：架橋剤（２））
　アンカー層材料が架橋剤（２）を含むことにより、アンカー層材料の硬化物であるアンカー層は、架橋構造を有する重合体を含む層となり得る。架橋剤（２）の例としては、易接着層材料に含まれうる架橋剤（１）の例と同様の例が挙げられる。 (Anchor Layer Material: Crosslinker (2))
By including the crosslinking agent (2) in the anchor layer material, the anchor layer, which is a cured product of the anchor layer material, can be a layer containing a polymer having a crosslinked structure. Examples of the crosslinking agent (2) include the same examples as the examples of the crosslinking agent (1) that can be included in the easy-adhesion layer material.
　アンカー層における、重合体（Ｐ２）に対する架橋剤（２）の割合は、所望の密着性及びその他の効果が発現される範囲に適宜調整しうる。具体的には、易接着層における重合体（Ｐ１）に対する架橋剤（１）の割合と同様の範囲としうる。 The ratio of the crosslinking agent (2) to the polymer (P2) in the anchor layer can be adjusted appropriately to a range in which the desired adhesion and other effects are achieved. Specifically, it can be in the same range as the ratio of the crosslinking agent (1) to the polymer (P1) in the easy-adhesion layer.
　（アンカー層材料：溶媒）
　アンカー層材料は、溶媒を含みうる。溶媒を含むことにより、アンカー層材料を液状の組成物とすることができ、塗布等の、アンカー層の形成の操作を容易にすることができる。溶媒としては、易接着層材料が含みうる溶媒の例と同様の例が挙げられる。また、溶媒は、１種類を単独で用いてもよく、２種類以上を任意の比率で組み合わせて用いてもよい。良好な揮発性の高さ及び他の成分を溶解する能力の高さから、水を、溶媒として好ましく用いうる。 (Anchor layer material: solvent)
The anchor layer material may contain a solvent. By containing a solvent, the anchor layer material can be made into a liquid composition, and the operation of forming the anchor layer, such as coating, can be facilitated. Examples of the solvent include the same examples as those of the solvent that the easy-adhesion layer material may contain. In addition, the solvent may be used alone or in combination of two or more types in any ratio. Water is preferably used as the solvent because of its good volatility and high ability to dissolve other components.
　アンカー層材料に含まれる溶媒の割合は、塗布等の、アンカー層の形成の操作に適した物性が得られるよう適宜調整しうる。具体的には、固形分濃度（溶媒以外の成分の割合）が好ましくは１重量％～２０重量％、より好ましくは２重量％～１５重量％となるよう割合を調整しうる。 The proportion of the solvent in the anchor layer material can be adjusted as appropriate to obtain properties suitable for the operation of forming the anchor layer, such as coating. Specifically, the proportion can be adjusted so that the solids concentration (proportion of components other than the solvent) is preferably 1% by weight to 20% by weight, and more preferably 2% by weight to 15% by weight.
　アンカー層材料は、更に任意の成分を含みうる。任意の成分の例としては、易接着層材料に含まれうる任意成分の例と同様の例が挙げられる。任意の成分は、１種類を単独で用いてもよく、２種類以上を任意の比率で組み合わせて用いてもよい。 The anchor layer material may further contain optional components. Examples of optional components include the same examples as the optional components that may be contained in the easy-adhesion layer material. One type of optional component may be used alone, or two or more types may be used in combination in any ratio.
　（アンカー層材料と易接着層材料との関係）
　アンカー層材料に含まれうる重合体（Ｐ２）と、易接着層材料に含まれうる重合体（Ｐ１）とは、共通する単量体単位を有することが好ましい。
　アンカー層材料が、重合体（Ｐ２）として、（メタ）アクリル酸エステル単位を含む重合体を含み、かつ易接着層材料が、重合体（Ｐ１）として、（メタ）アクリル酸エステル単位を含む重合体を含み、かつ、重合体（Ｐ１）と重合体（Ｐ２）とが、共通する（メタ）アクリル酸エステル単位を有することがより好ましい。 (Relationship between anchor layer material and easy-adhesion layer material)
The polymer (P2) that can be contained in the anchor layer material and the polymer (P1) that can be contained in the easy-adhesion layer material preferably have a common monomer unit.
It is more preferable that the anchor layer material contains a polymer containing a (meth)acrylic acid ester unit as the polymer (P2), and the easy-adhesion layer material contains a polymer containing a (meth)acrylic acid ester unit as the polymer (P1), and that the polymer (P1) and the polymer (P2) have a common (meth)acrylic acid ester unit.
　重合体（Ｐ１）と重合体（Ｐ２）とが、「共通する（メタ）アクリル酸エステル単位を有する」とは、重合体（Ｐ１）及び重合体（Ｐ２）のいずれもが、共通するアクリル酸エステル単位を有するか及び／又は共通するメタクリル酸エステル単位を有することを意味する。特に、良好な密着性を得る観点からは、「共通する（メタ）アクリル酸エステル単位」として、メタクリル酸エステル単位を有することが好ましく、メタクリル酸メチル単位を有することがさらに好ましい。 The phrase "Polymer (P1) and Polymer (P2) having common (meth)acrylic acid ester units" means that both Polymer (P1) and Polymer (P2) have common acrylic acid ester units and/or common methacrylic acid ester units. In particular, from the viewpoint of obtaining good adhesion, it is preferable for the "common (meth)acrylic acid ester units" to have methacrylic acid ester units, and it is even more preferable for them to have methyl methacrylate units.
　さらにより具体的には、重合体（Ｐ１）及び重合体（Ｐ２）のいずれもが、好ましくはメチルメタクリレート単位及びブチルアクリレート単位を有する重合体であり、より好ましくはメチルメタクリレートとブチルアクリレートとの共重合体である。 More specifically, both polymer (P1) and polymer (P2) are preferably polymers having methyl methacrylate units and butyl acrylate units, and more preferably copolymers of methyl methacrylate and butyl acrylate.
　アンカー層材料に含まれうる架橋剤（２）と、易接着剤材料に含まれうる架橋剤（１）とは、同じ架橋剤であることが好ましい。より具体的には、架橋剤（１）及び架橋剤（２）のいずれもが、メチルメタクリレート及び２－イソプロペニルオキサゾリンの共重合体であることがより好ましい。 The crosslinking agent (2) that can be contained in the anchor layer material and the crosslinking agent (1) that can be contained in the easy-adhesive material are preferably the same crosslinking agent. More specifically, it is more preferable that both the crosslinking agent (1) and the crosslinking agent (2) are copolymers of methyl methacrylate and 2-isopropenyl oxazoline.
［１．４．トップ層］
　トップ層は、好ましくは、トップ層材料の硬化物である。トップ層は、好ましくはトップ層材料の塗布により形成された、塗布層である。トップ層材料は、好ましくは重合体（Ｐ３）を含む材料である。 1.4. Top Layer
The top layer is preferably a cured product of the top layer material. The top layer is preferably a coated layer formed by coating the top layer material. The top layer material is preferably a material containing a polymer (P3).
　（トップ層材料：重合体（Ｐ３））
　トップ層材料に含まれうる重合体（Ｐ３）としては、正の固有複屈折を有する重合体を用いてもよいが、広帯域波長フィルムとしての複層フィルムを容易に製造する観点では、負の固有複屈折を有する重合体が好ましい。 (Top Layer Material: Polymer (P3))
As the polymer (P3) that can be included in the top layer material, a polymer having positive intrinsic birefringence may be used, but from the viewpoint of easily producing a multilayer film as a broadband wavelength film, a polymer having negative intrinsic birefringence is preferred.
　負の固有複屈折を有する重合体の例を挙げると、スチレン又はスチレン誘導体の単独重合体、並びに、スチレン又はスチレン誘導体と任意のモノマーとの共重合体を含むスチレン系重合体（例、ポリスチレン、ポリ（２－ビニルナフタレン））；ポリアクリロニトリル重合体；ポリメチルメタクリレート重合体；これらの多元共重合ポリマー；並びに、セルロースエステル重合体等のセルロース化合物などが挙げられる。これらの重合体は、１種類を単独で用いてもよく、２種類以上を任意の比率で組み合わせて用いてもよい。中でも、スチレン系単量体単位を有する重合体又はセルロースエステル重合体が好ましく、スチレン系単量体単位を有する重合体がより好ましい。ここで、「スチレン系単量体」の文言は、スチレン単量体、スチレン誘導体単量体、及びそれらの組み合わせを意味する。 Examples of polymers having negative intrinsic birefringence include homopolymers of styrene or styrene derivatives, and styrene-based polymers including copolymers of styrene or styrene derivatives with any monomer (e.g., polystyrene, poly(2-vinylnaphthalene)); polyacrylonitrile polymers; polymethyl methacrylate polymers; multicomponent copolymers thereof; and cellulose compounds such as cellulose ester polymers. These polymers may be used alone or in combination of two or more types in any ratio. Among these, polymers having styrene-based monomer units or cellulose ester polymers are preferred, and polymers having styrene-based monomer units are more preferred. Here, the term "styrene-based monomer" refers to styrene monomers, styrene derivative monomers, and combinations thereof.
　スチレン又はスチレン誘導体と共重合する任意のモノマーの例としては、アクリロニトリル、無水マレイン酸、メチルメタクリレート、及びブタジエンが挙げられる。また、これらの重合体は、１種類を単独で用いてもよく、２種類以上を任意の比率で組み合わせて用いてもよい。 Examples of optional monomers that copolymerize with styrene or styrene derivatives include acrylonitrile, maleic anhydride, methyl methacrylate, and butadiene. These polymers may be used alone or in combination of two or more in any ratio.
　スチレン誘導体の例としては、スチレンのベンゼン環、α位、若しくは、β位から選ばれる１以上の置換位置において置換基を有する誘導体、及びこれらの水素化物が挙げられる。置換基の例としては、ハロゲン原子、アルキル基、アルケニル基、芳香族基、アルコキシ基、及びアルコキシカルボニル基が挙げられる。置換基が炭素含有基である場合の、一つの置換基当たりの炭素数は、１～６個としうる。また、ベンゼン環の複数の置換位置における置換基が結合して環を形成した構造を有する誘導体（例えばビニルナフタレン）もスチレン誘導体に含まれる。 Examples of styrene derivatives include derivatives having substituents at one or more substitution positions selected from the benzene ring, α-position, or β-position of styrene, and hydrogenated versions of these. Examples of the substituents include halogen atoms, alkyl groups, alkenyl groups, aromatic groups, alkoxy groups, and alkoxycarbonyl groups. When the substituents are carbon-containing groups, the number of carbon atoms per substituent may be 1 to 6. Styrene derivatives also include derivatives having a structure in which substituents at multiple substitution positions on the benzene ring are bonded to form a ring (e.g., vinylnaphthalene).
　スチレン系単量体の具体例としては、スチレン、ハロゲン化スチレン、ハロゲン化アルキルスチレン、アルキルスチレン、アルケニルスチレン、アルコキシスチレン、アルコキシカルボニルスチレン、及びこれらの水素化物が挙げられる。 Specific examples of styrene monomers include styrene, halogenated styrene, halogenated alkylstyrene, alkylstyrene, alkenylstyrene, alkoxystyrene, alkoxycarbonylstyrene, and hydrogenated versions of these.
　ハロゲン化スチレンの例としては、クロロスチレン、ブロモスチレン、及びフルオロスチレンが挙げられる。ハロゲン化アルキルスチレンの例としては、クロロメチルスチレンが挙げられる。 Examples of halogenated styrenes include chlorostyrene, bromostyrene, and fluorostyrene. An example of a halogenated alkylstyrene is chloromethylstyrene.
　アルキルスチレンの例としては、メチルスチレン、エチルスチレン、イソプロピルスチレン、ｔ－ブチルスチレン、及び２，４－ジメチルスチレンが挙げられる。アルケニルスチレンの例としては、ビニルスチレンが挙げられる。 Examples of alkylstyrenes include methylstyrene, ethylstyrene, isopropylstyrene, t-butylstyrene, and 2,4-dimethylstyrene. Examples of alkenylstyrenes include vinylstyrene.
　アルコキシスチレンの例としては、メトキシスチレン及びエトキシスチレンが挙げられる。アルコキシカルボニルスチレンの例としては、ビニル安息香酸エステルが挙げられる。 Examples of alkoxystyrenes include methoxystyrene and ethoxystyrene. Examples of alkoxycarbonylstyrenes include vinyl benzoate.
　その他のスチレン系単量体の例としては、フェニルスチレン及びビニルナフタレンが挙げられる。 Other examples of styrene monomers include phenylstyrene and vinylnaphthalene.
　負の固有複屈折を有するセルロースエステル重合体の例としては、アシル化によってセルロースに適切なアリール基を導入したセルロースエステル重合体が挙げられる。 An example of a cellulose ester polymer with negative intrinsic birefringence is a cellulose ester polymer in which an appropriate aryl group has been introduced into cellulose by acylation.
　トップ層材料を構成する重合体（Ｐ３）の特に好ましい例としては、スチレン又はスチレン誘導体と無水マレイン酸との共重合体が挙げられる。スチレン又はスチレン誘導体と無水マレイン酸との共重合体は、耐熱性が高いという観点から特に好ましい。この共重合体において、スチレン系重合体１００重量部に対して、無水マレイン酸単位の量は、好ましくは５重量部以上、より好ましくは１０重量部以上、特に好ましくは１５重量部以上であり、好ましくは３０重量部以下、より好ましくは２８重量部以下、特に好ましくは２６重量部以下である。無水マレイン酸単位とは、無水マレイン酸を重合して形成される構造を有する構造単位のことをいう。 A particularly preferred example of the polymer (P3) constituting the top layer material is a copolymer of styrene or a styrene derivative and maleic anhydride. A copolymer of styrene or a styrene derivative and maleic anhydride is particularly preferred from the viewpoint of high heat resistance. In this copolymer, the amount of maleic anhydride units is preferably 5 parts by weight or more, more preferably 10 parts by weight or more, particularly preferably 15 parts by weight or more, and preferably 30 parts by weight or less, more preferably 28 parts by weight or less, particularly preferably 26 parts by weight or less, per 100 parts by weight of the styrene-based polymer. A maleic anhydride unit refers to a structural unit having a structure formed by polymerizing maleic anhydride.
　トップ層材料の固形分（溶媒以外の成分の全量）における重合体（Ｐ３）の割合は、好ましくは５０重量％～１００重量％、より好ましくは７０重量％～１００重量％、特に好ましくは９０重量％～１００重量％である。重合体（Ｐ３）の割合が前記範囲にある場合、トップ層が適切な光学特性を発現できる。 The proportion of polymer (P3) in the solid content (total amount of components other than the solvent) of the top layer material is preferably 50% by weight to 100% by weight, more preferably 70% by weight to 100% by weight, and particularly preferably 90% by weight to 100% by weight. When the proportion of polymer (P3) is within the above range, the top layer can exhibit appropriate optical properties.
　（トップ層材料：溶媒）
　トップ層材料は、溶媒を含みうる。溶媒を含むことにより、トップ層材料を液状の組成物とすることができ、塗布等の、トップ層の形成の操作を容易にすることができる。溶媒としては、易接着層材料に含まれうる溶媒の例と同様の例が挙げられる。溶媒は、１種類を単独で用いてもよく、２種類以上を任意の比率で組み合わせて用いてもよい。良好な揮発性の高さ及び他の成分を溶解する能力の高さから、メチルエチルケトン、メチルイソブチルケトン又はこれらの混合物等のケトンを、溶媒として好ましく用いうる。 (Top layer material: solvent)
The top layer material may contain a solvent. By containing a solvent, the top layer material can be a liquid composition, and the operation of forming the top layer, such as coating, can be facilitated. Examples of the solvent include the same examples as those of the solvent that can be contained in the easy-adhesion layer material. The solvent may be used alone or in combination of two or more types in any ratio. Ketones such as methyl ethyl ketone, methyl isobutyl ketone, or mixtures thereof can be preferably used as the solvent because of their good volatility and high ability to dissolve other components.
　トップ層材料に含まれる溶媒の割合は、塗布等の、トップ層の形成の操作に適した物性が得られるよう適宜調整しうる。具体的には、固形分濃度（溶媒以外の成分の割合）が好ましくは５重量％～２５重量％、より好ましくは１０重量％～２０重量％となるよう割合を調整しうる。 The proportion of solvent in the top layer material can be adjusted as appropriate to obtain physical properties suitable for the operation of forming the top layer, such as coating. Specifically, the proportion can be adjusted so that the solids concentration (proportion of components other than the solvent) is preferably 5% to 25% by weight, more preferably 10% to 20% by weight.
　（トップ層材料：添加剤（ｔ））
　トップ層材料は、さらに、任意に添加剤（ｔ）を含みうる。トップ層材料において、添加剤（ｔ）は、通常主成分である重合体（Ｐ３）より、重量比での含有割合が少ない別成分である。添加剤（ｔ）は、重合体（Ｐ３）と相溶可能な物質とすることが好ましい。具体的には、添加剤（ｔ）を含む場合は、得られる複層フィルムのヘイズの要件を充足するよう、その種類を適宜選択することが好ましい。 (Top Layer Material: Additive (t))
The top layer material may further contain an optional additive (t). In the top layer material, the additive (t) is a separate component that is usually contained in a smaller weight ratio than the polymer (P3), which is the main component. The additive (t) is preferably a substance that is compatible with the polymer (P3). Specifically, when the additive (t) is contained, it is preferable to appropriately select the type of additive (t) so as to satisfy the haze requirements of the resulting multilayer film.
　添加剤（ｔ）は、トップ層の光学異方性の発現の程度を所望の範囲に調整する等の機能を発現しうる。即ち、最終的な延伸後の複層フィルムが有する所望の光学的特性を得るのに適合したトップ層の厚みが、過度に薄い場合、成型の精度が低下し、トップ層の表面の面状ムラが大きくなり得る。このような場合において、負の固有複屈折を有する重合体（Ｐ３）と組み合わせて、正の固有複屈折を有する添加剤（ｔ）をトップ層材料に加えることにより、トップ層の表面の面状ムラを改善することが可能となる。 Additive (t) can perform functions such as adjusting the degree of optical anisotropy of the top layer to a desired range. In other words, if the thickness of the top layer suitable for obtaining the desired optical properties of the final stretched multilayer film is excessively thin, the molding precision decreases and the surface unevenness of the top layer may become large. In such a case, by adding additive (t) having positive intrinsic birefringence to the top layer material in combination with polymer (P3) having negative intrinsic birefringence, it is possible to improve the surface unevenness of the top layer.
　添加剤（ｔ）の例としては、（メタ）アクリル重合体、スチレン重合体、（メタ）アクリル－スチレン共重合体、ポリエステル、ポリカーボネート、及びオレフィン重合体等の重合体が挙げられる。これらの重合体は、１種類を単独で用いてもよく、２種類以上を任意の比率で組み合わせて用いてもよく、各樹脂の共重合体であってもよい。特に、（メタ）アクリル重合体、スチレン重合体、及び（メタ）アクリル－スチレン共重合体は、負の固有複屈折値を有する重合体（Ｐ３）と相溶する可能性が高いことから好ましい。 Examples of additives (t) include polymers such as (meth)acrylic polymers, styrene polymers, (meth)acrylic-styrene copolymers, polyesters, polycarbonates, and olefin polymers. These polymers may be used alone or in combination of two or more in any ratio, or may be copolymers of each resin. In particular, (meth)acrylic polymers, styrene polymers, and (meth)acrylic-styrene copolymers are preferred because they are highly likely to be compatible with the polymer (P3) having a negative intrinsic birefringence value.
　好ましい重合体（Ｐ３）との相溶性、並びに上に述べた添加剤としての特性及びその他の本発明の要件を良好に充足させる観点から、添加剤（ｔ）の特に好ましい例としては、（メタ）アクリル酸エステル単位及びスチレン系単量体単位を含む共重合体（例えば、商品名「ＴＸ－１００Ｓ」、デンカ社製、メチルメタクリレート及びスチレンの共重合体）が挙げられる。 A particularly preferred example of additive (t) from the viewpoint of compatibility with the preferred polymer (P3), and of satisfactorily satisfying the above-mentioned additive properties and other requirements of the present invention, is a copolymer containing (meth)acrylic acid ester units and styrene-based monomer units (for example, product name "TX-100S", manufactured by Denka Co., Ltd., a copolymer of methyl methacrylate and styrene).
　トップ層材料が添加剤（ｔ）を含む場合、重合体（Ｐ３）に対する添加剤（ｔ）の割合は、トップ層の光学異方性の発現の程度を所望の範囲に調整する等の所望の光学的効果及びその他の効果が発現される範囲に適宜調整しうる。具体的には、トップ層材料が添加剤（ｔ）を含む場合、重合体（Ｐ３）１００重量部に対する添加剤（ｔ）の割合は、好ましくは０重量部より多く、好ましくは５重量部以上であり、好ましくは７５重量部以下、より好ましくは７０重量部以下、更に好ましくは５０重量部以下、更に好ましくは２５重量部以下としうる。 When the top layer material contains additive (t), the ratio of additive (t) to polymer (P3) can be adjusted appropriately to a range in which the desired optical effects and other effects are achieved, such as adjusting the degree of optical anisotropy of the top layer to a desired range. Specifically, when the top layer material contains additive (t), the ratio of additive (t) to 100 parts by weight of polymer (P3) is preferably more than 0 parts by weight, preferably 5 parts by weight or more, and preferably 75 parts by weight or less, more preferably 70 parts by weight or less, even more preferably 50 parts by weight or less, and even more preferably 25 parts by weight or less.
　（トップ層材料：その他の成分）
　トップ層材料は、更に任意の成分を含みうる。任意の成分としては、例えば熱可塑性樹脂（ｓ）が含みうる任意の成分と同じ例が挙げられる。任意の成分は、１種類を単独で用いてもよく、２種類以上を任意の比率で組み合わせて用いてもよい。 (Top layer material: other ingredients)
The top layer material may further include optional components. Examples of optional components include the same optional components as those included in the thermoplastic resin (s). The optional components may be used alone or in combination of two or more in any ratio.
［２．易接着層、アンカー層、及びトップ層、並びに複層フィルムの製造方法］
　易接着層は、通常、上に述べた易接着層材料の硬化物であり、アンカー層は、通常、上に述べたアンカー層材料の硬化物であり、トップ層は、通常、上に述べたトップ層材料の硬化物である。易接着層材料、アンカー層材料及びトップ層材料からそれぞれ易接着層、アンカー層及びトップ層を形成する方法は、特に限定されず、いずれかの既知の方法を適宜選択して使用しうる。具体的には、基材フィルムの表面に易接着層材料を塗布して易接着層材料の塗膜を形成し、かかる塗膜を乾燥させることにより、易接着層を形成しうる。また、易接着層の表面にアンカー層材料を塗布してアンカー層材料の塗膜を形成し、かかる塗膜を乾燥させることにより、アンカー層を形成しうる。さらに、アンカー層の表面にトップ層材料を塗布してトップ層材料の塗膜を形成し、かかる塗膜を乾燥させることにより、トップ層を形成しうる。 [2. Method for producing adhesive layer, anchor layer, top layer, and multilayer film]
The easy-adhesion layer is usually a cured product of the easy-adhesion layer material described above, the anchor layer is usually a cured product of the anchor layer material described above, and the top layer is usually a cured product of the top layer material described above. The method of forming the easy-adhesion layer, anchor layer, and top layer from the easy-adhesion layer material, anchor layer material, and top layer material, respectively, is not particularly limited, and any known method can be appropriately selected and used. Specifically, the easy-adhesion layer can be formed by applying the easy-adhesion layer material to the surface of the base film to form a coating film of the easy-adhesion layer material and drying the coating film. In addition, the anchor layer can be formed by applying the anchor layer material to the surface of the easy-adhesion layer to form a coating film of the anchor layer material and drying the coating film. Furthermore, the top layer can be formed by applying the top layer material to the surface of the anchor layer to form a coating film of the top layer material and drying the coating film.
　易接着層材料、アンカー層材料及びトップ層材料はそれぞれ、溶媒を含みうる。易接着層の形成、アンカー層の形成及びトップ層の形成に際しては、これらの溶媒は揮発し、その一部または全部が層から消失しうる。また、易接着層材料及びアンカー層材料は、架橋剤等の、反応性の材料を含みうる。易接着層の形成及びアンカー層の形成に際しては、これらの反応性の材料は、反応し、架橋等の、重合体分子の構造の一部を構成する要素となり得る。 The easy-adhesion layer material, anchor layer material, and top layer material may each contain a solvent. When forming the easy-adhesion layer, anchor layer, and top layer, these solvents may volatilize and disappear in part or in whole from the layers. In addition, the easy-adhesion layer material and anchor layer material may contain reactive materials such as crosslinking agents. When forming the easy-adhesion layer and anchor layer, these reactive materials may react and become elements that form part of the structure of polymer molecules, such as crosslinking.
　本実施形態の複層フィルムは、任意の方法により製造されうる。例えば、複層フィルムは、下記の工程（１）、（２－１）、（２－２）、（３）、（４）、（５－１）、（５－２）、（６－１）、（６－２）、（７）をこの順に含む製造方法により製造されうる。複層フィルムの製造方法は、下記工程の他に、任意の工程を含んでいてもよい。 The multilayer film of this embodiment can be manufactured by any method. For example, the multilayer film can be manufactured by a manufacturing method including the following steps (1), (2-1), (2-2), (3), (4), (5-1), (5-2), (6-1), (6-2), and (7) in this order. The manufacturing method for the multilayer film may include any steps in addition to the steps below.
　工程（１）：長尺の基材フィルムを用意する工程。
　工程（２－１）：前記基材フィルム上に、液状の易接着層材料を塗布し、前記易接着層材料の塗膜を形成する工程。
　工程（２－２）：前記易接着層材料の塗膜を乾燥させて易接着層を形成し、前記基材フィルムと前記易接着層とを備える複層物（Ｉ）を得る工程。
　工程（３）：前記複層物（Ｉ）を延伸して、複層物（ＩＩ）を得る工程。
　工程（４）：前記複層物（ＩＩ）を巻き取る工程。
　工程（５－１）：巻き取られた前記複層物（ＩＩ）を巻き出し、前記複層物（ＩＩ）の前記易接着層上に、液状のアンカー層材料を塗布し、前記アンカー層材料の塗膜を形成する工程。
　工程（５－２）：前記アンカー層材料の塗膜を乾燥させてアンカー層を形成し、前記基材フィルムと前記易接着層と前記アンカー層とをこの順で備える複層物（ＩＩＩ）を得る工程。
　工程（６－１）：前記複層物（ＩＩＩ）の前記アンカー層上に、液状のトップ層材料を塗布し、前記トップ層材料の塗膜を形成する工程。
　工程（６－２）：前記トップ層材料の塗膜を乾燥させてトップ層を形成し、前記基材フィルムと前記易接着層と前記アンカー層と前記トップ層とをこの順で備える複層物（ＩＶ）を得る工程。
　工程（７）：前記複層物（ＩＶ）を延伸して複層フィルムを得る工程。 Step (1): A step of preparing a long base film.
Step (2-1): A step of applying a liquid adhesive layer material onto the base film to form a coating film of the adhesive layer material.
Step (2-2): A step of drying the coating film of the easy-adhesion layer material to form an easy-adhesion layer and obtain a multilayer body (I) having the base film and the easy-adhesion layer.
Step (3): A step of stretching the multi-layered product (I) to obtain a multi-layered product (II).
Step (4): A step of winding up the laminate (II).
Step (5-1): A step of unwinding the wound multilayer material (II) and applying a liquid anchor layer material onto the easy-adhesion layer of the multilayer material (II) to form a coating film of the anchor layer material.
Step (5-2): A step of drying the coating film of the anchor layer material to form an anchor layer, thereby obtaining a multilayer body (III) having the base film, the easy-adhesion layer, and the anchor layer in this order.
Step (6-1): A step of applying a liquid top layer material onto the anchor layer of the multilayer structure (III) to form a coating film of the top layer material.
Step (6-2): A step of drying the coating of the top layer material to form a top layer, thereby obtaining a multilayer body (IV) having the base film, the easy-adhesion layer, the anchor layer, and the top layer in this order.
Step (7): A step of stretching the multilayer product (IV) to obtain a multilayer film.
［２．１．工程（１）］
　工程（１）では、基材フィルムを用意する。通常、基材フィルムは、熱可塑性樹脂（ｓ）を成形して形成される。通常、基材フィルムは、フィルムとして形成される。長尺の複層フィルムを効率的に製造する観点では、基材フィルムは、長尺のフィルムとして形成されることが好ましい。基材フィルムが長尺のフィルムである場合、基材フィルムをその長手方向に沿って、搬送ライン上に搬送させ、これ以降の工程を、搬送ラインの下流において連続的に行うことが可能となる。 [2.1. Step (1)]
In step (1), a base film is prepared. The base film is usually formed by molding a thermoplastic resin (s). The base film is usually formed as a film. From the viewpoint of efficient production of the multilayer film, it is preferable that the base film is formed as a long film. When the base film is a long film, the base film is cut along its longitudinal direction. The substrate can then be transported onto a transport line, and subsequent steps can be carried out continuously downstream of the transport line.
　基材フィルムの形成方法は、特に制限されない。基材フィルムの形成方法としては、例えば、溶融成形法又は溶液流延法が挙げられる。溶融成形法のより具体的な例としては、押出成形法、プレス成形法、インフレーション成形法、射出成形法、ブロー成形法、及び延伸成形法が挙げられる。これらの方法の中でも、機械強度及び表面精度に優れた基材フィルムを得る観点では、押出成形法、インフレーション成形法又はプレス成形法が好ましく、中でも効率よく簡単に基材フィルムを製造できる観点から押出成形法が特に好ましい。 The method for forming the substrate film is not particularly limited. Examples of methods for forming the substrate film include melt molding and solution casting. More specific examples of melt molding include extrusion molding, press molding, inflation molding, injection molding, blow molding, and stretch molding. Among these methods, from the viewpoint of obtaining a substrate film with excellent mechanical strength and surface precision, extrusion molding, inflation molding, and press molding are preferred, and among these, extrusion molding is particularly preferred from the viewpoint of being able to efficiently and easily produce a substrate film.
［２．２．工程（２－１）］
　工程（２－１）では、前記基材フィルム上に、液状の易接着層材料を塗布し、前記易接着層材料の塗膜を形成する。 [2.2. Step (2-1)]
In the step (2-1), a liquid adhesive layer material is applied onto the base film to form a coating film of the adhesive layer material.
　液状の易接着層層材料の塗布方法の例としては、カーテンコーティング法、押し出しコーティング法、ロールコーティング法、スピンコーティング法、ディップコーティング法、バーコーティング法、スプレーコーティング法、スライドコーティング法、印刷コーティング法、グラビアコーティング法、ダイコーティング法、及びギャップコーティング法などが挙げられる。 Examples of methods for applying liquid adhesive layer materials include curtain coating, extrusion coating, roll coating, spin coating, dip coating, bar coating, spray coating, slide coating, print coating, gravure coating, die coating, and gap coating.
　易接着層材料の塗膜厚みは、製造される複層フィルムにおいて、易接着層が所望の厚みＴ１となるように、調整されうる。 The coating thickness of the easy-adhesion layer material can be adjusted so that the easy-adhesion layer has the desired thickness T1 in the multilayer film produced.
［２．３．工程（２－２）］
　工程（２－２）では、前記易接着層材料の塗膜を乾燥させて易接着層を形成し、前記基材フィルムと前記易接着層とを備える複層物（Ｉ）を得る。工程（２－２）において、易接着層材料の塗膜の乾燥は、例えば、自然乾燥、加熱乾燥、減圧乾燥、減圧加熱乾燥等の乾燥方法で行いうる。 [2.3. Step (2-2)]
In step (2-2), the coating film of the easy-adhesion layer material is dried to form an easy-adhesion layer, and a multilayer body (I) including the base film and the easy-adhesion layer is obtained. In 2-2), the coating film of the easy-adhesion layer material can be dried by a drying method such as natural drying, heat drying, reduced pressure drying, reduced pressure heat drying, etc.
　また、工程（２－２）において、任意に、易接着層材料の塗膜に対し、架橋を促進させる処理を行ってもよい。かかる処理により、架橋剤（１）の架橋反応を進行させて、易接着層の機械的強度及び耐溶媒性を向上させることができる。架橋処理としては、例えば、加熱処理、紫外線等の活性エネルギー線の照射処理、などが挙げられる。 In addition, in step (2-2), a treatment for promoting crosslinking may be optionally performed on the coating film of the easy-adhesion layer material. Such a treatment can promote the crosslinking reaction of the crosslinking agent (1) and improve the mechanical strength and solvent resistance of the easy-adhesion layer. Examples of crosslinking treatments include heating treatment and irradiation with active energy rays such as ultraviolet rays.
［２．４．工程（３）］
　工程（３）では、前記複層物（Ｉ）を延伸して、複層物（ＩＩ）を得る。 [2.4. Step (3)]
In the step (3), the multi-layered product (I) is stretched to obtain a multi-layered product (II).
　工程（３）における延伸方向は、複層フィルムに発現させたい光学特性に応じて設定しうる。例えば、正の固有複屈折を有する熱可塑性樹脂（ｓ）の基材フィルムと負の固有複屈折を有する重合体（Ｐ３）を含むトップ層とを組み合わせて、複層フィルムとして長尺の広帯域波長フィルムを製造する場合、工程（３）における延伸方向は、基材フィルムの幅方向に対して平行でも垂直でもない斜め方向であることが好ましい。この場合、延伸方向が基材フィルムの幅方向に対してなす角度は、好ましくは３５°以上、より好ましくは３７°以上、更に好ましくは４０°以上、特に好ましくは４２°以上であり、好ましくは５５°以下、より好ましくは５３°以下、更に好ましくは５０°以下、特に好ましくは４８°以下である。 The stretching direction in step (3) can be set according to the optical properties to be expressed in the multilayer film. For example, when a long broadband wavelength film is manufactured as a multilayer film by combining a base film of a thermoplastic resin (s) having positive intrinsic birefringence with a top layer containing a polymer (P3) having negative intrinsic birefringence, the stretching direction in step (3) is preferably an oblique direction that is neither parallel nor perpendicular to the width direction of the base film. In this case, the angle that the stretching direction makes with the width direction of the base film is preferably 35° or more, more preferably 37° or more, even more preferably 40° or more, particularly preferably 42° or more, and is preferably 55° or less, more preferably 53° or less, even more preferably 50° or less, particularly preferably 48° or less.
　工程（３）における延伸倍率は、好ましくは１．１倍以上、より好ましくは１．２倍以上であり、好ましくは２．５倍以下、より好ましくは２．０倍以下である。延伸倍率が前記範囲の下限値以上である場合、延伸方向の屈折率を大きくできる。また、延伸倍率が前記範囲の上限値以下である場合、延伸された基材フィルムの遅相軸の方向を容易に制御することができる。 The stretching ratio in step (3) is preferably 1.1 times or more, more preferably 1.2 times or more, and is preferably 2.5 times or less, more preferably 2.0 times or less. When the stretching ratio is equal to or greater than the lower limit of the range, the refractive index in the stretching direction can be increased. When the stretching ratio is equal to or less than the upper limit of the range, the direction of the slow axis of the stretched substrate film can be easily controlled.
　工程（３）における延伸温度は、好ましくはＴｇＡ以上、より好ましくは（ＴｇＡ＋２）℃以上、特に好ましくは（ＴｇＡ＋５）℃以上であり、好ましくは（ＴｇＡ＋４０）℃以下、より好ましくは（ＴｇＡ＋３５）℃以下、特に好ましくは（ＴｇＡ＋３０）℃以下である。ここで、ＴｇＡは、熱可塑性樹脂（ｓ）のガラス転移温度を表す。延伸温度が前記の範囲にある場合、基材フィルムに含まれる分子を効果的に配向させることができるので、所望の光学特性を有する複層フィルムの製造を円滑に行うことができる。 The stretching temperature in step (3) is preferably TgA or higher, more preferably (TgA+2)°C or higher, particularly preferably (TgA+5)°C or higher, and is preferably (TgA+40)°C or lower, more preferably (TgA+35)°C or lower, particularly preferably (TgA+30)°C or lower. Here, TgA represents the glass transition temperature of the thermoplastic resin (s). When the stretching temperature is within the above range, the molecules contained in the base film can be effectively oriented, and therefore a multilayer film having the desired optical properties can be smoothly manufactured.
　複層物（ＩＩ）の遅相軸の方向は、複層物（ＩＩ）の幅方向に対して平行でも垂直でもない斜め方向にあることが好ましい。複層フィルムとして広帯域波長フィルムを得る観点では、複層物（ＩＩ）の配向角は、好ましくは２５°以上、より好ましくは３０°以上、更に好ましくは３５°以上であり、好ましくは５５°未満、より好ましくは５０°未満、更に好ましくは４８°未満である。 The direction of the slow axis of the laminate (II) is preferably in an oblique direction that is neither parallel nor perpendicular to the width direction of the laminate (II). From the viewpoint of obtaining a broadband wavelength film as the laminate film, the orientation angle of the laminate (II) is preferably 25° or more, more preferably 30° or more, even more preferably 35° or more, and is preferably less than 55°, more preferably less than 50°, even more preferably less than 48°.
　複層物（ＩＩ）のレターデーション等の光学特性は、複層フィルムに発現させたい光学特性に応じて設定しうる。例えば、複層フィルムとして広帯域波長フィルムを製造する場合、複層物（ＩＩ）の面内レターデーションＲｅは、好ましくは１８０ｎｍ以上、より好ましくは１９０ｎｍ以上、特に好ましくは２００ｎｍ以上であり、好ましくは２５０ｎｍ以下、より好ましくは２４０ｎｍ以下、特に好ましくは２３０ｎｍ以下である。 The optical properties such as retardation of the multilayer material (II) can be set according to the optical properties desired to be expressed in the multilayer film. For example, when a broadband wavelength film is produced as the multilayer film, the in-plane retardation Re of the multilayer material (II) is preferably 180 nm or more, more preferably 190 nm or more, particularly preferably 200 nm or more, and is preferably 250 nm or less, more preferably 240 nm or less, particularly preferably 230 nm or less.
　複層物（ＩＩ）の厚みは、所望の複層フィルムが得られる範囲で任意に設定しうる。その具体的な厚みは、好ましくは３０μｍ以上、より好ましくは３５μｍ以上、特に好ましくは４０μｍ以上であり、好ましくは８０μｍ以下、より好ましくは７０μｍ以下、特に好ましくは６０μｍ以下である。 The thickness of the multilayer material (II) can be set arbitrarily within the range in which the desired multilayer film can be obtained. The specific thickness is preferably 30 μm or more, more preferably 35 μm or more, particularly preferably 40 μm or more, and is preferably 80 μm or less, more preferably 70 μm or less, particularly preferably 60 μm or less.
［２．５．工程（４）］
　工程（４）では、前記複層物（ＩＩ）を巻き取る。本実施形態の製造方法では、基材フィルムと、基材フィルムの一方の表面に直接接して設けられた、有機粒子（ＮＰ）を含む易接着層材料の硬化物である易接着層とを備える複層物（ＩＩ）を得うる。複層物（ＩＩ）の表面に有機粒子（ＮＰ）を含む易接着層が露出しているので、複層物（ＩＩ）は滑り性が向上している。そのため、複層物（ＩＩ）を巻き取っても、巻き重なった複層物（ＩＩ）同士が密着して擦れることによる傷が、生じにくい。さらに、後述する工程（５－１）において、複層物（ＩＩ）を円滑に巻き出しうる。 [2.5. Step (4)]
In step (4), the laminate (II) is wound up. In the manufacturing method of the present embodiment, a base film and organic particles (NP) provided directly on one surface of the base film are A multi-layered product (II) having an easy-adhesion layer which is a cured product of an easy-adhesion layer material containing the organic particles (NP) can be obtained. Therefore, even when the multi-layered material (II) is wound up, the wound multi-layered material (II) is not scratched due to friction between the layers of the multi-layered material (II). Furthermore, in the step (5-1) described below, the multi-layered product (II) can be smoothly unwound.
　複層物（ＩＩ）が備える、基材フィルムと易接着層との動摩擦係数は、より効果的に欠陥を低減しうるので、好ましくは０．８以下、より好ましくは０．７５以下であり、小さいほど好ましく、通常０以上であり、０より大きくてもよい。基材フィルムと易接着層との動摩擦係数は、下記の方法により測定しうる。 The coefficient of dynamic friction between the base film and the easy-adhesion layer of the multilayered product (II) is preferably 0.8 or less, more preferably 0.75 or less, since this can more effectively reduce defects. The smaller the coefficient, the better, and it is usually 0 or more, but may be greater than 0. The coefficient of dynamic friction between the base film and the easy-adhesion layer can be measured by the following method.
　（動摩擦係数の測定方法）
　複層物（ＩＩ）を、８０ｍｍ×２００ｍｍのサイズに２枚切り出して、２枚の試験片を得る。２枚の試験片を、それらが備える基材フィルムと易接着層とが向き合うように重ねて、ＪＩＳ　Ｋ７１２５（１９９９）に準拠して、基材フィルムと易接着層との間の動摩擦係数を測定する。測定は、摩擦測定器（例えば、東洋精機製作所製、「ＴＲ－２」）を用い、２００ｇ荷重、移動距離１００ｍｍ、移動速度５００ｍｍ／分として行いうる。 (Method of measuring the dynamic friction coefficient)
The laminate (II) is cut into two pieces each having a size of 80 mm x 200 mm to obtain two test pieces. The two test pieces are stacked so that the substrate film and the easy-adhesion layer thereof face each other, and the dynamic friction coefficient between the substrate film and the easy-adhesion layer is measured in accordance with JIS K7125 (1999). The measurement can be performed using a friction meter (e.g., "TR-2" manufactured by Toyo Seiki Seisakusho) with a load of 200 g, a moving distance of 100 mm, and a moving speed of 500 mm/min.
［２．６．工程（５－１）］
　工程（５－１）では、巻き取られた前記複層物（ＩＩ）を巻き出し、前記複層物（ＩＩ）の前記易接着層上に、液状のアンカー層材料を塗布し、前記アンカー層材料の塗膜を形成する。液状のアンカー層材料の塗布方法の例としては、工程（２－１）において液状の易接着層材料の塗布方法の例として挙げた例と同様の例が挙げられる。 [2.6. Step (5-1)]
In step (5-1), the wound multilayered product (II) is unwound, and a liquid anchor layer material is applied onto the adhesive layer of the multilayered product (II), and the anchor layer A coating film of the material is formed. Examples of the coating method of the liquid anchor layer material include the same examples as those given as examples of the coating method of the liquid easy-adhesion layer material in step (2-1). .
　アンカー層材料の塗膜厚みは、製造される複層フィルムにおいて、アンカー層が所望の厚みＴ２となるように、調整されうる。 The coating thickness of the anchor layer material can be adjusted so that the anchor layer has the desired thickness T2 in the multilayer film produced.
［２．７．工程（５－２）］
　工程（５－２）では、アンカー層材料の塗膜を乾燥させてアンカー層を形成し、前記基材フィルムと前記易接着層と前記アンカー層とをこの順で備える複層物（ＩＩＩ）を得る。
　アンカー層材料の塗膜の乾燥方法の例としては、工程（２－２）において易接着層材料の塗膜の乾燥方法の例として挙げた例と同様の例が挙げられる。 [2.7. Step (5-2)]
In step (5-2), the coating film of the anchor layer material is dried to form an anchor layer, and a multilayer body (III) having the base film, the easy-adhesion layer, and the anchor layer in this order is obtained. obtain.
Examples of the method for drying the coating film of the anchor layer material include the same methods as those given as examples of the method for drying the coating film of the easy-adhesion layer material in the step (2-2).
［２．８．工程（６－１）］
　工程（６－１）では、複層物（ＩＩＩ）の前記アンカー層上に、液状のトップ層材料を塗布し、前記トップ層材料の塗膜を形成する。液状のトップ層材料の塗布方法の例としては、工程（２－１）において液状の易接着層材料の塗布方法の例として挙げた例と同様の例が挙げられる。 [2.8. Step (6-1)]
In step (6-1), a liquid top layer material is applied onto the anchor layer of the multi-layered product (III) to form a coating film of the top layer material. Examples of the method include the same methods as those given as examples of the coating method of the liquid easy-adhesion layer material in the step (2-1).
　トップ層材料の塗膜厚みは、製造される複層フィルムにおいて、トップ層が所望の厚みとなるように、調整されうる。 The coating thickness of the top layer material can be adjusted so that the top layer has the desired thickness in the resulting multilayer film.
［２．９．工程（６－２）］
　工程（６－２）では、トップ層材料の塗膜を乾燥させてトップ層を形成し、前記基材フィルムと前記易接着層と前記アンカー層と前記トップ層とをこの順で備える複層物（ＩＶ）を得る。
　トップ層材料の塗膜の乾燥方法の例としては、工程（２－２）において易接着層材料の塗膜の乾燥方法の例として挙げた例と同様の例が挙げられ、好ましくは、オーブンを用いた加熱乾燥である。 [2.9. Step (6-2)]
In step (6-2), the coating film of the top layer material is dried to form a top layer, and a multilayer structure having the base film, the easy-adhesion layer, the anchor layer, and the top layer in this order is obtained. (IV) is obtained.
Examples of the method for drying the coating film of the top layer material include the same methods as those given as examples of the method for drying the coating film of the easy-adhesion layer material in step (2-2), and preferably, drying the coating film using an oven. The heat drying method used was
［２．１０．工程（７）］
　工程（７）では、複層物（ＩＶ）を延伸して複層フィルムを得る。
　工程（７）における複層物（ＩＶ）の延伸は、通常、オーブン内において行われる。
　工程（７）における延伸方向は、複層フィルムに発現させたい光学特性に応じて設定しうる。例えば、正の固有複屈折を有する熱可塑性樹脂（ｓ）の層である基材フィルムと負の固有複屈折を有する重合体（Ｐ３）を含むトップ層とを組み合わせて、複層フィルムとして長尺の広帯域波長フィルムを製造する場合、工程（７）における延伸方向は、複層物（ＩＶ）の長手方向に実質的に平行な方向であることが好ましい。この場合、延伸方向が複層物（ＩＶ）の幅方向に対してなす角度は、好ましくは８５°以上、より好ましくは８７°以上、更に好ましくは８９°以上であり、好ましくは９５°以下、より好ましくは９３°以下、更に好ましくは９１°以下であり、特に好ましくは９０°である。 [2.10. Step (7)]
In step (7), the multilayer product (IV) is stretched to obtain a multilayer film.
The stretching of the laminate (IV) in the step (7) is usually carried out in an oven.
The stretching direction in step (7) can be set according to the optical properties to be expressed in the multilayer film. For example, When a long broadband wavelength film is produced as a multilayer film by combining with a top layer containing a polymer (P3) having an intrinsic birefringence, the stretching direction in step (7) is the same as that of the multilayer (IV). It is preferable that the stretching direction is substantially parallel to the longitudinal direction. In this case, the angle between the stretching direction and the width direction of the laminate (IV) is preferably 85° or more, more preferably 87° or more. It is more preferably 89° or more, and is preferably 95° or less, more preferably 93° or less, further preferably 91° or less, and particularly preferably 90°.
　複層物（ＩＶ）の長手方向に実質的に平行な方向に延伸を行う場合、工程（７）における延伸は、自由一軸延伸として行ってもよい。自由一軸延伸とは、ある一方向への延伸であって、延伸される方向以外の方向に拘束力を加えない延伸のことをいう。よって、例えば、複層物（ＩＶ）の長手方向に実質的に平行な方向への自由一軸延伸は、複層物（ＩＶ）の幅方向の端部を拘束しないで行なう長手方向への延伸でありうる。 When stretching is performed in a direction substantially parallel to the longitudinal direction of the multi-layered product (IV), the stretching in step (7) may be performed as free uniaxial stretching. Free uniaxial stretching refers to stretching in a certain direction in which no restraining force is applied in any direction other than the direction of stretching. Thus, for example, free uniaxial stretching in a direction substantially parallel to the longitudinal direction of the multi-layered product (IV) can be stretching in the longitudinal direction without restraining the ends of the multi-layered product (IV) in the width direction.
　工程（７）における延伸倍率は、好ましくは１．１倍以上、より好ましくは１．１５倍以上、特に好ましくは１．２倍以上であり、好ましくは２．０倍以下、より好ましくは１．８倍以下、特に好ましくは１．６倍以下である。工程（７）における延伸倍率が前記範囲にある場合、所望の光学特性を有する複層フィルムを容易に得ることができる。 The stretching ratio in step (7) is preferably 1.1 times or more, more preferably 1.15 times or more, particularly preferably 1.2 times or more, and is preferably 2.0 times or less, more preferably 1.8 times or less, particularly preferably 1.6 times or less. When the stretching ratio in step (7) is within the above range, a multilayer film having the desired optical properties can be easily obtained.
［３．複層フィルムの性質等］
　本実施形態のフィルムは、密着性が良好なフィルムとしうる。ここで密着性とは、基材フィルムとトップ層との間の、剥離に対する抵抗性の指標である。密着性は、ＪＩＳ　Ｋ５６００－５－６（１９９９）で定められたクロスカット試験により行いうる。
　具体的には、試料である複層フィルムの、トップ層、アンカー層、及び易接着層に、１ｍｍ間隔で５ｍｍ×５ｍｍの範囲に切り込みを入れ、１ｍｍ角の正方形を２５個作成する。試料のトップ層側の表面に、セロハンテープを貼り付けて、セロハンテープを剥離し、剥がれずに複層フィルムの基材フィルムに付着して残った正方形の数を計測することで、密着性を評価しうる。残った正方形の数が多いほど、密着性が高い。本実施形態では、この試験で２０／２５以上の密着性を発現しうる。 [3. Properties of multi-layer film]
The film of the present embodiment can be a film with good adhesion. Here, adhesion is an index of resistance to peeling between the base film and the top layer. The adhesion can be measured by a cross-cut test defined in JIS K5600-5-6 (1999).
Specifically, the top layer, anchor layer, and easy-adhesion layer of the multilayer film sample are cut at 1 mm intervals in a range of 5 mm x 5 mm to create 25 squares with a side of 1 mm. The adhesion can be evaluated by attaching cellophane tape to the surface of the top layer side of the sample, peeling the cellophane tape, and measuring the number of squares that remain attached to the base film of the multilayer film without peeling. The more squares that remain, the higher the adhesion. In this embodiment, this test can produce an adhesion of 20/25 or more.
　複層フィルムの密着性が良好であることにより、複層フィルムを組み込んだ表示装置の耐久性を向上させることができる。加えて、表示装置の製造工程におけるリワークを容易にすることができる。例えば、複層フィルムを、表示素子（液晶表示装置の液晶セル等）を備えるパネルに貼合し、その後貼合に不良があることが判明し、パネルを再利用するために複層フィルムを剥離する場合、複層フィルムの層の一部のみがパネルに残存するといった不具合の発生を低減することが可能となる。 The good adhesion of the multilayer film can improve the durability of a display device incorporating the multilayer film. In addition, it can facilitate rework during the manufacturing process of the display device. For example, if the multilayer film is attached to a panel containing a display element (such as a liquid crystal cell of a liquid crystal display device) and then it is discovered that there is a defect in the attachment, and the multilayer film is peeled off to reuse the panel, it can reduce the occurrence of defects such as only part of the layers of the multilayer film remaining on the panel.
　複層フィルムは、高い透明性を有することが好ましい。よって、複層フィルムは、高い全光線透過率を有することが好ましい。複層フィルムの具体的な全光線透過率は、好ましくは８０％以上、より好ましくは８５％以上、特に好ましくは８８％以上である。光線透過率は、ＪＩＳ　Ｋ０１１５に準拠して、分光光度計を用いて、波長４００ｎｍ～７００ｎｍの範囲で測定しうる。 The multilayer film preferably has high transparency. Therefore, it is preferable that the multilayer film has high total light transmittance. The specific total light transmittance of the multilayer film is preferably 80% or more, more preferably 85% or more, and particularly preferably 88% or more. The light transmittance can be measured in the wavelength range of 400 nm to 700 nm using a spectrophotometer in accordance with JIS K0115.
　複層フィルム全体の厚みは、特段の制限は無いが、好ましくは３０μｍ以上、より好ましくは３５μｍ以上、特に好ましくは４０μｍ以上であり、好ましくは１００μｍ以下、より好ましくは９０μｍ以下、特に好ましくは８０μｍ以下である。 There are no particular limitations on the overall thickness of the multilayer film, but it is preferably 30 μm or more, more preferably 35 μm or more, and particularly preferably 40 μm or more, and is preferably 100 μm or less, more preferably 90 μm or less, and particularly preferably 80 μm or less.
　複層フィルムは、長尺の形状を有することが好ましい。長尺の複層フィルムの幅は、特段の制限は無いが、好ましくは１３００ｍｍ以上、より好ましくは１４００ｍｍ以上、特に好ましくは１５００ｍｍ以上であり、好ましくは２０００ｍｍ以下、より好ましくは１８００ｍｍ以下である。 The multilayer film preferably has a long shape. There are no particular limitations on the width of the long multilayer film, but it is preferably 1300 mm or more, more preferably 1400 mm or more, particularly preferably 1500 mm or more, and is preferably 2000 mm or less, more preferably 1800 mm or less.
　複層フィルムの用途に制限は無いが、優れた光学特性を活用する観点では、光学フィルムとして用いることが好ましい。好ましい用途の具体例を挙げると、広帯域波長フィルムとしての複層フィルムは、直線偏光子と貼り合わせて、円偏光板を製造するために用いてもよい。上述した複層フィルムは、面内レターデーションのバラツキが小さいので、複層フィルムを備える円偏光板は当該円偏光板を透過する円偏光の偏光状態のバラツキを抑制できる。よって、この円偏光板は、高い均一性で光の反射を抑制する反射抑制フィルムとして用いることができる。 There are no limitations to the uses of the multilayer film, but from the viewpoint of utilizing its excellent optical properties, it is preferable to use it as an optical film. As a specific example of a preferable use, the multilayer film as a broadband wavelength film may be laminated with a linear polarizer and used to manufacture a circular polarizing plate. Since the above-mentioned multilayer film has small variation in in-plane retardation, a circular polarizing plate equipped with the multilayer film can suppress variation in the polarization state of the circularly polarized light that passes through the circular polarizing plate. Therefore, this circular polarizing plate can be used as a reflection-suppressing film that suppresses light reflection with high uniformity.
　以下、実施例を示して本発明について具体的に説明する。ただし、本発明は以下に示す実施例に限定されるものではなく、本発明の請求の範囲及びその均等の範囲を逸脱しない範囲において任意に変更して実施しうる。 The present invention will be specifically described below with reference to examples. However, the present invention is not limited to the examples shown below, and can be modified as desired without departing from the scope of the claims of the present invention and the scope of equivalents thereto.
　以下の説明において、量を表す「％」及び「部」は、別に断らない限り、重量基準である。また、以下に説明する操作は、別に断らない限り、常温（２０℃±１５℃）及び常圧（１ａｔｍ）の条件において行った。 In the following explanation, the amounts in "%" and "parts" are by weight unless otherwise specified. Furthermore, the operations described below were carried out at room temperature (20°C ± 15°C) and normal pressure (1 atm) unless otherwise specified.
［評価方法］
　（層の厚み）
　フィルム又はそれを構成する各層の厚みは、フィルメトリクス社の反射分光式膜厚測定システム「Ｆ２０」を用いて測定した。 [Evaluation method]
(Layer thickness)
The thickness of the film or each layer constituting the film was measured using a Filmetrics Inc. reflection spectroscopic film thickness measurement system "F20".
　（平均粒子径）
　粒子の重量平均粒子径は、動的光散乱法により、米国Ｍｉｃｒｏｔｒａｃ社製「Ｎａｎｏｔｒａｃ　ＵＰＡ－ＥＸ１５０」により測定した。 (Average particle size)
The weight average particle size of the particles was measured by dynamic light scattering using "Nanotrac UPA-EX150" manufactured by Microtrac Corporation, USA.
　（面内レターデーションＲｅ）
　試料のフィルムの面内レターデーションＲｅは、位相差計（Ａｘｏｍｅｔｒｉｃｓ社製「ＡｘｏＳｃａｎ」）により測定した。 (In-plane retardation Re)
The in-plane retardation Re of the sample film was measured by a phase difference meter (Axometrics'"AxoScan").
　（密着性の評価方法）
　密着性の評価方法として、ＪＩＳ　Ｋ５６００－５－６（１９９９）で定められたクロスカット試験を行った。
　試料である複層フィルムの、トップ層、アンカー層、及び易接着層に、１ｍｍ間隔で５ｍｍ×５ｍｍの範囲に切り込みを入れ、１ｍｍ角の正方形を２５個作成した。試料のトップ層側の表面に、セロハンテープを貼り付けて、セロハンテープを剥離した。剥がれずに複層フィルムの基材フィルムに付着して残った正方形の数を計測し、併せて、以下の評価基準により評価した。
　良：残った正方形の数が２０／２５以上２５／２５以下である。
　不良：残った正方形の数が１９／２５以下である。 (Method of evaluating adhesion)
The adhesion was evaluated by a cross-cut test according to JIS K5600-5-6 (1999).
The top layer, anchor layer, and easy-adhesion layer of the multilayer film sample were cut at 1 mm intervals in a range of 5 mm x 5 mm to create 25 squares with a side of 1 mm. Cellophane tape was attached to the surface of the top layer side of the sample, and the cellophane tape was peeled off. The number of squares remaining on the base film of the multilayer film without peeling off was counted, and was also evaluated according to the following evaluation criteria.
Good: The number of remaining squares is between 20/25 and 25/25.
Poor: 19/25 or less squares remaining.
　（外観観察による異物数）
　複層フィルムを黒板に乗せ、蛍光灯の下で目視により面状観察を行った。１ｍ×１ｍの範囲で複層フィルムを観察し、最大径が１００μｍ以上のサイズである異物を欠陥としてカウントした。 (Number of foreign objects by visual observation)
The multilayer film was placed on a blackboard and the surface condition was visually observed under a fluorescent lamp. The multilayer film was observed in an area of 1 m x 1 m, and foreign matter with a maximum diameter of 100 μm or more was counted as a defect.
［実施例１］
　（１－１．基材フィルム）
　ペレット状のノルボルネン系樹脂（日本ゼオン社製；ガラス転移温度１２６℃）を１００℃で５時間乾燥した。乾燥した樹脂を、押出機に供給し、ポリマーパイプ及びポリマーフィルターを経て、Ｔダイからキャスティングドラム上にシート状に押し出し、押出成形を行った。成形された樹脂を冷却し、厚み７０μｍの長尺の基材フィルム（ｉ）を得た。 [Example 1]
(1-1. Base Film)
Pellet-shaped norbornene-based resin (manufactured by Zeon Corporation; glass transition temperature 126° C.) was dried for 5 hours at 100° C. The dried resin was fed to an extruder, passed through a polymer pipe and a polymer filter, and extruded from a T-die onto a casting drum in the form of a sheet, thereby carrying out extrusion molding. The molded resin was cooled to obtain a long substrate film (i) having a thickness of 70 μm.
　（１－２．易接着層材料１）
　下記の材料を混合して、未硬化状態のアクリル樹脂として固形分８．７％の液状の易接着層材料１を得た。
　重合体（Ｐ１）を含む材料：アクリル樹脂として、メチルメタクリレート／ブチルアクリレート共重合体（重合比はメチルメタクリレート６０重量％及びブチルアクリレート４０重量％）の水分散体（固形分濃度５０％）１４部
　架橋剤（１）を含む材料：オキサゾリン基含有（メタ）アクリル架橋剤（商品名「エポクロスＷＳ－７００」、日本触媒製、メチルメタクリレート及び２－イソプロペニルオキサゾリンの共重合体、固形分濃度２５重量％、オキサゾリン基量４．５ｍｍｏｌ／（ｇ固形分））６部、
　有機粒子（ＮＰ）としての（メタ）アクリル重合体粒子の水分散液（日本触媒社製「エポスターＭＸ２００Ｗ」；ポリメタクリル酸メチル系架橋重合体、重量平均粒子径３００ｎｍ、固形分濃度１０重量％）を２部
　濡れ剤としてのアセチレン系界面活性剤（エアープロダクツアンドケミカルズ社製「サーフィノール４４０」）を固形分合計量に対して０．５重量％
　水：７８部 (1-2. Easy-adhesion layer material 1)
The following materials were mixed to obtain a liquid adhesive layer material 1 having a solid content of 8.7% as an uncured acrylic resin.
Material containing polymer (P1): 14 parts of an aqueous dispersion (solid content concentration 50%) of a methyl methacrylate/butyl acrylate copolymer (polymerization ratio is 60% by weight of methyl methacrylate and 40% by weight of butyl acrylate) as an acrylic resin Material containing crosslinking agent (1): 6 parts of an oxazoline group-containing (meth)acrylic crosslinking agent (product name "Epocross WS-700", manufactured by Nippon Shokubai, a copolymer of methyl methacrylate and 2-isopropenyl oxazoline, solid content concentration 25% by weight, oxazoline group amount 4.5 mmol/(g solid content)),
2 parts of an aqueous dispersion of (meth)acrylic polymer particles as organic particles (NP) ("Eposter MX200W" manufactured by Nippon Shokubai Co., Ltd.; polymethyl methacrylate-based crosslinked polymer, weight average particle size 300 nm, solid content concentration 10% by weight) 0.5% by weight of an acetylene-based surfactant as a wetting agent ("Surfynol 440" manufactured by Air Products and Chemicals Co., Ltd.) based on the total solid content
Water: 78 parts
　（１－３．複層物（Ｉ））
　（１－１）で得た基材フィルム（ｉ）の表面にコロナ処理を施した。コロナ処理は、コロナ処理装置（春日電機社製）を用いて、ライン速度１０ｍ／ｍｉｎ、窒素雰囲気下、出力１．５ｋＷの条件で行った。 (1-3. Multi-layered material (I))
The surface of the base film (i) obtained in (1-1) was subjected to a corona treatment using a corona treatment device (manufactured by Kasuga Denki Co., Ltd.) under conditions of a line speed of 10 m/min, a nitrogen atmosphere, and an output of 1.5 kW.
　基材フィルム（ｉ）の、コロナ処理が施された表面に、（１－２）で得た易接着層材料１を塗布し、易接着層材料の塗膜を形成した。塗布は、ロールコーターを用いて、塗膜の乾燥後の厚みが０．１μｍになる条件で行った。 The easy-adhesion layer material 1 obtained in (1-2) was applied to the corona-treated surface of the base film (i) to form a coating of the easy-adhesion layer material. The application was performed using a roll coater under conditions such that the coating would have a thickness of 0.1 μm after drying.
　その後、易接着層材料の塗膜を温度１１０℃で６０秒間加熱して、基材フィルム（ｉ）上に易接着層（ｉ）を形成した。これにより、（基材フィルム（ｉ））／（易接着層（ｉ））の層構成を有する複層物（Ｉ）を得た。得られた複層物（Ｉ）はロールに巻き取って回収した。 Then, the coating of the easy-adhesion layer material was heated at a temperature of 110°C for 60 seconds to form an easy-adhesion layer (i) on the base film (i). This resulted in a multilayered product (I) having a layer structure of (base film (i))/(easy-adhesion layer (i)). The resulting multilayered product (I) was wound up on a roll and collected.
　（１－４．複層物（ＩＩ））
　複層物（Ｉ）をロールから巻き出した。
　巻き出した複層物（Ｉ）を、テンター延伸機に連続的に供給し、テンター延伸機によって複層物（Ｉ）を延伸した。延伸の方向は、複層物（Ｉ）の幅方向に対して４５°の角度をなす方向とした。延伸温度は１３５℃、延伸倍率は１．５倍とした。かかる延伸により、（基材フィルム（ｉｉ））／（易接着層（ｉｉ））の層構成を有する複層物（ＩＩ）を得た。基材フィルム（ｉｉ）は、基材フィルム（ｉ）の延伸の結果得られた層であり、易接着層（ｉｉ）は、易接着層（ｉ）の延伸の結果得られた層である。複層物（ＩＩ）における基材フィルム（ｉｉ）の、フィルム幅方向に対する配向角は４５°、複層物（ＩＩ）の面内レターデーションＲｅは２１５ｎｍであった。複層物（ＩＩ）における基材フィルム（ｉｉ）の厚みは４７μｍであり、易接着層（ｉｉ）の厚みは０．０８５μｍであった。得られた複層物（ＩＩ）はロールに巻き取って回収した。 (1-4. Multi-layered material (II))
The laminate (I) was unwound from the roll.
The unwound multilayered product (I) was continuously supplied to a tenter stretching machine, and the multilayered product (I) was stretched by the tenter stretching machine. The stretching direction was a direction forming an angle of 45° with respect to the width direction of the multilayered product (I). The stretching temperature was 135°C, and the stretching ratio was 1.5 times. By such stretching, a multilayered product (II) having a layer structure of (substrate film (ii))/(easy adhesion layer (ii)) was obtained. The substrate film (ii) is a layer obtained as a result of stretching the substrate film (i), and the easy adhesion layer (ii) is a layer obtained as a result of stretching the easy adhesion layer (i). The orientation angle of the substrate film (ii) in the multilayered product (II) with respect to the film width direction was 45°, and the in-plane retardation Re of the multilayered product (II) was 215 nm. The thickness of the base film (ii) in the multilayered product (II) was 47 μm, and the thickness of the easy-adhesion layer (ii) was 0.085 μm. The obtained multilayered product (II) was wound around a roll and collected.
　（１－５．アンカー層材料）
　下記の材料を混合して、未硬化状態のアクリル樹脂として固形分８．５％の液状の水系樹脂を得た。この水系樹脂を、アンカー層材料１として用いた。
　重合体（Ｐ２）を含む材料：アクリル樹脂として、メチルメタクリレート／ブチルアクリレート共重合体（重合比はメチルメタクリレート６０重量％及びブチルアクリレート４０重量％）の水分散体（固形分濃度５０％）１４部
　架橋剤（２）を含む材料：オキサゾリン基含有（メタ）アクリル架橋剤（商品名「エポクロスＷＳ－７００」、日本触媒製、メチルメタクリレート及び２－イソプロペニルオキサゾリンの共重合体、固形分濃度２５重量％、オキサゾリン基量４．５ｍｍｏｌ／（ｇ固形分））６部
　濡れ剤：アセチレン系界面活性剤（エアープロダクツアンドケミカルズ社製「サーフィノール４４０」）固形分合計量に対して０．５重量％
　水：８０部 (1-5. Anchor Layer Materials)
The following materials were mixed to obtain a liquid water-based resin having a solid content of 8.5% as an uncured acrylic resin. This water-based resin was used as anchor layer material 1.
Material containing polymer (P2): 14 parts of an aqueous dispersion (solid concentration 50%) of methyl methacrylate/butyl acrylate copolymer (polymerization ratio is 60% by weight of methyl methacrylate and 40% by weight of butyl acrylate) as an acrylic resin Material containing crosslinking agent (2): 6 parts of an oxazoline group-containing (meth)acrylic crosslinking agent (product name "Epocross WS-700", manufactured by Nippon Shokubai, a copolymer of methyl methacrylate and 2-isopropenyl oxazoline, solid concentration 25% by weight, oxazoline group amount 4.5 mmol/(g solid content)) Wetting agent: 0.5% by weight of an acetylene-based surfactant ("Surfynol 440" manufactured by Air Products and Chemicals Co., Ltd.) based on the total solid content
Water: 80 parts
　（１－６．複層物（ＩＩＩ））
　（１－４）で得た複層物（ＩＩ）をロールから巻き出した。
　巻き出した複層物（ＩＩ）の、基材フィルム（ｉｉ）の表面（即ち易接着層（ｉｉ）面）に、（１－５）で得たアンカー層材料１を塗布して、アンカー層材料１の塗膜を形成した。塗布は、フィルムの搬送方向と逆向きに回転するリバースグラビアを用いて行った。 (1-6. Multi-layered material (III))
The laminate (II) obtained in (1-4) was unwound from the roll.
The anchor layer material 1 obtained in (1-5) was applied to the surface of the base film (ii) of the unwound multilayered product (II) (i.e., the surface of the easy-adhesion layer (ii)) to form a coating film of the anchor layer material 1. The coating was performed using a reverse gravure that rotates in the opposite direction to the film transport direction.
　塗布されたアンカー層材料の塗膜を１２０℃で乾燥させた。乾燥の際、アンカー層材料の架橋が進行して、アンカー層（ｉ）が形成された。その結果、（アンカー層（ｉ））／（易接着層（ｉｉ））／（基材フィルム（ｉｉ））の層構成を有する長尺の複層物（ＩＩＩ）を得た。得られた複層物（ＩＩＩ）におけるアンカー層（ｉ）及び易接着層（ｉｉ）の合計の厚みは、０．２０５μｍであった。 The applied coating of the anchor layer material was dried at 120°C. During drying, crosslinking of the anchor layer material proceeded, forming an anchor layer (i). As a result, a long multilayered product (III) having a layer structure of (anchor layer (i))/(easy adhesion layer (ii))/(base film (ii)) was obtained. The total thickness of the anchor layer (i) and easy adhesion layer (ii) in the obtained multilayered product (III) was 0.205 μm.
　（１－７．複層物（ＩＶ））
　固有複屈折率が負の樹脂としてスチレン－無水マレイン酸共重合体樹脂（ノヴァ・ケミカル社製「Ｄｙｌａｒｋ　Ｄ３３２」）を用意した。また、メチルエチルケトン及びメチルイソブチルケトンの混合溶媒（重量比８：２）を準備した。
　スチレン－無水マレイン酸共重合体樹脂１００部を混合溶媒に溶かし、さらに可塑剤としてリン酸トリフェニルを５部添加して、固形分濃度１５重量％の液状のトップ層材料１を得た。 (1-7. Laminated material (IV))
A styrene-maleic anhydride copolymer resin ("Dylark D332" manufactured by Nova Chemical Co.) was prepared as a resin having a negative intrinsic birefringence. A mixed solvent of methyl ethyl ketone and methyl isobutyl ketone (weight ratio 8:2) was also prepared.
100 parts of styrene-maleic anhydride copolymer resin was dissolved in a mixed solvent, and 5 parts of triphenyl phosphate was further added as a plasticizer to obtain a liquid top layer material 1 having a solid content concentration of 15% by weight.
　得られたアンカー層（ｉ）側の表面に、ダイコーティングによりトップ層材料１を塗布して、トップ層材料１の塗膜を形成した。 Top layer material 1 was applied by die coating to the surface of the resulting anchor layer (i) side to form a coating of top layer material 1.
　その後、形成されたトップ層材料１の塗膜を、１２０℃で乾燥させて、トップ層（ｉ）を形成した。その結果、（トップ層（ｉ））／（アンカー層（ｉ））／（易接着層（ｉｉ））／（基材フィルム（ｉｉ））の層構成を有する長尺の複層物（ＩＶ）を得た。得られた複層物（ＩＶ）におけるトップ層（ｉ）の厚みは、８μｍであった。得られた複層物（ＩＶ）は、マスキングフィルムと貼合後、ロールに巻き取って回収した。 Then, the coating film of the top layer material 1 thus formed was dried at 120°C to form the top layer (i). As a result, a long multilayered product (IV) having a layer structure of (top layer (i))/(anchor layer (i))/(easy adhesion layer (ii))/(base film (ii)) was obtained. The thickness of the top layer (i) in the obtained multilayered product (IV) was 8 μm. The obtained multilayered product (IV) was laminated with a masking film, and then wound up on a roll and collected.
　（１－８．複層フィルム）
　巻き出した複層物（ＩＶ）を、縦延伸機に連続的に供給し、縦延伸機によって複層物（ＩＶ）を延伸した。延伸は、複層物（ＩＶ）の長手方向への自由一軸延伸とした。延伸温度は１２７℃、延伸倍率は１．４倍とした。かかる延伸により、（トップ層（ｉｉ））／（アンカー層（ｉｉ））／（易接着層（ｉｉｉ））／（基材フィルム（ｉｉｉ））の層構成を有する長尺の複層フィルムを得た。トップ層（ｉｉ）は、トップ層（ｉ）の延伸の結果得られた層であり、アンカー層（ｉｉ）は、アンカー層（ｉ）の延伸の結果得られた層であり、易接着層（ｉｉｉ）は、易接着層（ｉｉ）の延伸の結果得られた層であり、基材フィルム（ｉｉｉ）は、基材フィルム（ｉｉ）の延伸の結果得られた層である。 (1-8. Multilayer film)
The unwound multilayered material (IV) was continuously supplied to a longitudinal stretching machine, and the multilayered material (IV) was stretched by the longitudinal stretching machine. The stretching was performed by free uniaxial stretching in the longitudinal direction of the multilayered material (IV). The stretching temperature was 127°C, and the stretching ratio was 1.4 times. By such stretching, a long multilayered film having a layer structure of (top layer (ii))/(anchor layer (ii))/(easy adhesion layer (iii))/(base film (iii)) was obtained. The top layer (ii) is a layer obtained as a result of stretching the top layer (i), the anchor layer (ii) is a layer obtained as a result of stretching the anchor layer (i), the easy adhesion layer (iii) is a layer obtained as a result of stretching the easy adhesion layer (ii), and the base film (iii) is a layer obtained as a result of stretching the base film (ii).
　得られた複層フィルムの外観を目視で検査し、フィルムの異物数の有無を評価した。
　また、得られた複層フィルムの密着性を評価したところ、すべての正方形が密着していることが分かった（２５／２５）。 The appearance of the resulting multilayer film was visually inspected, and the presence or absence of foreign matter in the film was evaluated.
The resulting multi-layer film was also evaluated for adhesion and found to have all squares in good adhesion (25/25).
［実施例２］
　（１－３）において、ロールコーターによる塗布条件を調整して、複層フィルムにおける易接着層の厚みが表に示す厚みとなるように、易接着層材料の塗膜の厚みを変更した。
　以上の事項以外は実施例１と同様に操作して、複層フィルムを得て、評価した。 [Example 2]
In (1-3), the coating conditions using a roll coater were adjusted to change the thickness of the coating of the adhesive layer material so that the thickness of the adhesive layer in the multilayer film was as shown in the table.
Except for the above, the same procedure as in Example 1 was repeated to obtain a multilayer film and evaluate it.
［実施例３］
　（１－２）において、有機粒子（ＮＰ）として、日本触媒社製「エポスターＭＸ２００Ｗ」（重量平均粒子径３００ｎｍ）の代わりに、日本触媒社製「エポスターＭＸ１００Ｗ」（重量平均粒子径１５０ｎｍ、固形分濃度１０％）を用いた。
　以上の事項以外は、実施例１と同様に操作して、複層フィルムを得て、評価した。 [Example 3]
In (1-2), as the organic particles (NP), "Eposter MX100W" (weight average particle diameter 150 nm, solid content concentration 10%) manufactured by Nippon Shokubai Co., Ltd. was used instead of "Eposter MX200W" (weight average particle diameter 300 nm) manufactured by Nippon Shokubai Co., Ltd.
Except for the above, the same procedure as in Example 1 was repeated to obtain a multilayer film and evaluate it.
［比較例１］
　（１－５）～（１－６）を行わなかった。
　（１－７）において、（１－４）で得た複層物（ＩＩ）の易接着層（ｉｉ）側の表面に、トップ層材料１を塗布し、トップ層材料１の塗膜を形成した。
　以上の事項以外は実施例１と同様に操作して、複層フィルムを得て、評価した。
　本例で得られた複層フィルムは、（トップ層（ｉｉ））／（易接着層（ｉｉｉ））／（基材フィルム（ｉｉｉ））の層構成を有する。 [Comparative Example 1]
(1-5) to (1-6) were not carried out.
In (1-7), the top layer material 1 was applied to the surface of the easily adhesive layer (ii) side of the multilayered product (II) obtained in (1-4) to form a coating film of the top layer material 1.
Except for the above, the same procedure as in Example 1 was repeated to obtain a multilayer film and evaluate it.
The multilayer film obtained in this example had a layer structure of (top layer (ii))/(easy-adhesion layer (iii))/(base film (iii)).
［比較例２］
　（１－６）において、リバースグラビアによる塗布条件を調整して、複層フィルムにおけるアンカー層の厚みが表に示す厚みとなるように、アンカー層材料の塗膜の厚みを変更した。
　以上の事項以外は実施例１と同様に操作して、複層フィルムを得て、評価した。 [Comparative Example 2]
In (1-6), the coating conditions by reverse gravure were adjusted to change the thickness of the coating film of the anchor layer material so that the thickness of the anchor layer in the multilayer film would be the thickness shown in the table.
Except for the above, the same procedure as in Example 1 was repeated to obtain a multilayer film and evaluate it.
［比較例３］
　（１－２）において、有機粒子（ＮＰ）として、日本触媒社製「エポスターＭＸ２００Ｗ」（重量平均粒子径３００ｎｍ）の代わりに、日本触媒社製「エポスターＭＸ１００Ｗ」（重量平均粒子径１５０ｎｍ、固形分濃度１０％）を用いた。
　（１－３）において、ロールコーターによる塗布条件を調整して、複層フィルムにおける易接着層の厚みが表に示す厚みとなるように、易接着層材料の塗膜の厚みを変更した。
　以上の事項以外は実施例１の（１－１）～（１－５）と同様に操作した。
　次いで、実施例１の（１－６）と同様に操作しようとしたが、複層物（ＩＩ）を巻き出す際に、複層物（ＩＩ）にしわが発生してアンカー層材料の塗布を行うことができず、複層フィルムを得られなかった。 [Comparative Example 3]
In (1-2), as the organic particles (NP), "Eposter MX100W" (weight average particle diameter 150 nm, solid content concentration 10%) manufactured by Nippon Shokubai Co., Ltd. was used instead of "Eposter MX200W" (weight average particle diameter 300 nm) manufactured by Nippon Shokubai Co., Ltd.
In (1-3), the coating conditions using a roll coater were adjusted to change the thickness of the coating of the adhesive layer material so that the thickness of the adhesive layer in the multilayer film was as shown in the table.
Except for the above, the same operations as in (1-1) to (1-5) of Example 1 were carried out.
Next, an attempt was made to operate in the same manner as in (1-6) of Example 1, but when unwinding the laminate (II), wrinkles occurred in the laminate (II), making it impossible to apply the anchor layer material, and a laminate film could not be obtained.
［結果］
　複層フィルムにおける各層の厚み及び複層フィルムの評価結果を下表に示す。 [result]
The thickness of each layer in the multilayer film and the evaluation results of the multilayer film are shown in the table below.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　表中、＊１は、（１－６）において複層物（ＩＩ）を巻き出す際に、複層物（ＩＩ）にしわが発生してアンカー層材料の塗布を行うことができず、複層フィルムを得られなかったため、評価できなかったことを示す。 In the table, *1 indicates that when unrolling the laminate (II) in (1-6), wrinkles occurred in the laminate (II), making it impossible to apply the anchor layer material, and therefore no laminate film could be obtained, and therefore evaluation was not possible.
　以上の結果より、実施例１～実施例３に係る複層フィルムは、密着性の評価が良好である。またＴ１／Ｔ３が０．６以下である、実施例１に係る複層フィルムは、欠陥数が０であり、密着性と欠陥の少なさとを高い基準で達成できることがわかる。
　一方、Ｔ１＋Ｔ２が１５０ｎｍ未満である、比較例１、２に係る複層フィルムは、密着性の評価が不良である。 From the above results, the multilayer films according to Examples 1 to 3 are evaluated as having good adhesion. In addition, the multilayer film according to Example 1, in which T1/T3 is 0.6 or less, has zero defects, and it is understood that the multilayer film can achieve high standards of adhesion and fewer defects.
On the other hand, the multilayer films according to Comparative Examples 1 and 2, in which T1+T2 is less than 150 nm, are evaluated as poor in adhesion.
　実施例１～３に係る複層フィルムの製造方法によれば、密着性に優れた複層フィルムを得ることができることがわかる。
　一方、Ｔ３がＴ１未満である、すなわち、Ｔ１／Ｔ３が１より大きい比較例３に係る複層フィルムの製造方法では、目的とする複層フィルムが得られない。これは、中間に得られる複層物（ＩＩ）の滑り性が十分でなかったためと推察される。 It can be seen that the multilayer film manufacturing methods according to Examples 1 to 3 can provide multilayer films with excellent adhesion.
On the other hand, the desired multilayer film cannot be obtained in the method for producing a multilayer film according to Comparative Example 3, in which T3 is less than T1, i.e., T1/T3 is greater than 1. This is presumably because the slipperiness of the multilayer material (II) obtained in the middle is insufficient.

Claims (10)

  1. 　基材フィルムと、前記基材フィルムの一方の表面に直接接して設けられた易接着層と、前記易接着層の表面に直接接して設けられたアンカー層と、前記アンカー層の表面に直接接して設けられたトップ層とを備える複層フィルムであって、
    　前記易接着層の厚みＴ１と前記アンカー層の厚みＴ２との合計厚み（Ｔ１＋Ｔ２）が、１５０ｎｍ以上であり、
    　前記易接着層は、平均粒子径Ｔ３が前記易接着層の厚みＴ１以上である有機粒子（ＮＰ）を含む、
    　複層フィルム。     A multilayer film comprising a base film, an easy-adhesion layer provided in direct contact with one surface of the base film, an anchor layer provided in direct contact with the surface of the easy-adhesion layer, and a top layer provided in direct contact with the surface of the anchor layer,
    The total thickness (T1 + T2) of the thickness T1 of the easy-adhesion layer and the thickness T2 of the anchor layer is 150 nm or more,
    The easy-adhesion layer contains organic particles (NP) having an average particle diameter T3 equal to or greater than the thickness T1 of the easy-adhesion layer,
    Multi-layer film.
  2. 　前記易接着層の厚みＴ１の前記有機粒子（ＮＰ）の平均粒子径Ｔ３に対する比率（Ｔ１／Ｔ３）が、０．６以下である、請求項１に記載の複層フィルム。 The multilayer film according to claim 1, wherein the ratio (T1/T3) of the thickness T1 of the easy-adhesion layer to the average particle diameter T3 of the organic particles (NP) is 0.6 or less.
  3. 　前記基材フィルムが、環状オレフィン系重合体を含む、請求項１に記載の複層フィルム。 The multilayer film according to claim 1, wherein the base film contains a cyclic olefin polymer.
  4. 　前記有機粒子（ＮＰ）が（メタ）アクリル重合体の粒子である、請求項１に記載の複層フィルム。 The multilayer film according to claim 1, wherein the organic particles (NP) are particles of a (meth)acrylic polymer.
  5. 　前記易接着層が、前記有機粒子（ＮＰ）と（メタ）アクリル酸エステル単位を有する重合体（Ｐ１）と架橋剤（１）とを含む易接着層材料の、硬化物である、請求項１に記載の複層フィルム。 The multilayer film according to claim 1, wherein the easy-adhesion layer is a cured product of an easy-adhesion layer material that contains the organic particles (NP), a polymer (P1) having (meth)acrylic acid ester units, and a crosslinking agent (1).
  6. 　前記アンカー層が、（メタ）アクリル酸エステル単位を有する重合体（Ｐ２）及び架橋剤（２）を含むアンカー層材料の、硬化物である、請求項１に記載の複層フィルム。 The multilayer film according to claim 1, wherein the anchor layer is a cured product of an anchor layer material containing a polymer (P2) having a (meth)acrylic acid ester unit and a crosslinking agent (2).
  7. 　前記易接着層が、前記有機粒子（ＮＰ）と（メタ）アクリル酸エステル単位を有する重合体（Ｐ１）と架橋剤（１）とを含む易接着層材料の、硬化物であり、
    　前記アンカー層が、（メタ）アクリル酸エステル単位を有する重合体（Ｐ２）及び架橋剤（２）を含むアンカー層材料の、硬化物であり、
    　前記重合体（Ｐ１）と前記重合体（Ｐ２）とが、共通する（メタ）アクリル酸エステル単位を有する、請求項１に記載の複層フィルム。     The easy-adhesion layer is a cured product of an easy-adhesion layer material containing the organic particles (NP), a polymer (P1) having a (meth)acrylic acid ester unit, and a crosslinking agent (1),
    the anchor layer is a cured product of an anchor layer material containing a polymer (P2) having a (meth)acrylic acid ester unit and a crosslinking agent (2),
    The multilayer film according to claim 1 , wherein the polymer (P1) and the polymer (P2) have a common (meth)acrylic acid ester unit.
  8. 　前記トップ層が、スチレン系単量体単位を有する重合体（Ｐ３）を含むトップ層材料の、硬化物である、請求項１に記載の複層フィルム。 The multilayer film according to claim 1, wherein the top layer is a cured product of a top layer material containing a polymer (P3) having a styrene-based monomer unit.
  9. 　延伸フィルムである、請求項１に記載の複層フィルム。 The multilayer film according to claim 1, which is a stretched film.
  10. 　請求項１～９のいずれか一項に記載の複層フィルムの製造方法であって、
    　長尺の基材フィルムを用意する工程（１）、
    　前記基材フィルム上に、液状の易接着層材料を塗布し、前記易接着層材料の塗膜を形成する工程（２－１）、
    　前記易接着層材料の塗膜を乾燥させて易接着層を形成し、前記基材フィルムと前記易接着層とを備える複層物（Ｉ）を得る工程（２－２）、
    　前記複層物（Ｉ）を延伸して、複層物（ＩＩ）を得る工程（３）、
    　前記複層物（ＩＩ）を巻き取る工程（４）、
    　巻き取られた前記複層物（ＩＩ）を巻き出し、前記複層物（ＩＩ）の前記易接着層上に、液状のアンカー層材料を塗布し、前記アンカー層材料の塗膜を形成する工程（５－１）、
    　前記アンカー層材料の塗膜を乾燥させてアンカー層を形成し、前記基材フィルムと前記易接着層と前記アンカー層とをこの順で備える複層物（ＩＩＩ）を得る工程（５－２）、
    　前記複層物（ＩＩＩ）の前記アンカー層上に、液状のトップ層材料を塗布し、前記トップ層材料の塗膜を形成する工程（６－１）、
    　前記トップ層材料の塗膜を乾燥させてトップ層を形成し、前記基材フィルムと前記易接着層と前記アンカー層と前記トップ層とをこの順で備える複層物（ＩＶ）を得る工程（６－２）、及び
    　前記複層物（ＩＶ）を延伸して複層フィルムを得る工程（７）、
    を含む、複層フィルムの製造方法。     A method for producing the multilayer film according to any one of claims 1 to 9,
    A step (1) of preparing a long substrate film;
    A step (2-1) of applying a liquid adhesive layer material onto the substrate film to form a coating film of the adhesive layer material;
    A step (2-2) of drying the coating film of the easy-adhesion layer material to form an easy-adhesion layer and obtain a multilayer body (I) having the base film and the easy-adhesion layer;
    A step (3) of stretching the multi-layered product (I) to obtain a multi-layered product (II);
    A step (4) of winding up the laminate (II);
    A step (5-1) of unwinding the wound multilayer material (II) and applying a liquid anchor layer material onto the easy-adhesion layer of the multilayer material (II) to form a coating film of the anchor layer material;
    A step (5-2) of drying the coating film of the anchor layer material to form an anchor layer, thereby obtaining a multilayer body (III) having the base film, the easy-adhesion layer, and the anchor layer in this order;
    A step (6-1) of applying a liquid top layer material onto the anchor layer of the multilayer structure (III) to form a coating film of the top layer material;
    A step (6-2) of drying the coating film of the top layer material to form a top layer and obtaining a multilayer body (IV) having the base film, the easy-adhesion layer, the anchor layer, and the top layer in this order; and A step (7) of stretching the multilayer body (IV) to obtain a multilayer film.
    A method for producing a multilayer film, comprising:
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