JP2021123059A - Laminate film - Google Patents

Abstract

To provide a laminate film that has excellent surface hardness and also features practical repeated bending properties.SOLUTION: A laminate film has a substrate film, an anchor coat layer, and a mesh-shaped inorganic matter-containing layer. The anchor coat layer and the inorganic matter-containing layer are provided in this order on the surface of the substrate film on at least one side.SELECTED DRAWING: None

Description

The present invention relates to a laminated film in which an anchor coat layer and an inorganic substance-containing layer are laminated on the surface of a base film.

In recent years, there has been a tendency for flexible substrates and flexible printed circuits to be used as electronic devices and the like become smaller and lighter. In addition, along with this trend, the demand for flexibility tends to increase also in display applications. The surface protective film for display screens used for such applications requires not only surface protective properties such as high hardness, scratch prevention, stain resistance, and abrasion resistance, but also high durability in terms of bendability. It was said that further performance improvement was requested.

Therefore, in recent years, many proposals have been made for surface protective films in order to improve flexibility or flexibility while maintaining high hardness and scratch resistance.
For example, in Patent Document 1, in a hard coat layer having a laminated structure, the elastic modulus of the intermediate layer is made larger than that of the surface layer to improve the surface hardness and prevent damage to the hard coat film due to stress concentration. The technical contents regarding the hard coat film which is hard to be scratched are disclosed.

Patent Document 2 discloses a hard coat layer having a laminated structure in which a radical material is used for the surface layer and a cationic material is used for the intermediate layer, and the interlayer adhesion is good.

Patent Document 3 discloses a technical content for controlling the elastic modulus of a hard coat coating film by including silica particles in the coating film.

In Patent Document 4, in the hard coat layer having a laminated structure, a coating film having a pencil scratch value of 4H or more is formed on a coating film having an elongation rate of 80% or more of the cured coating film. The technical contents relating to the hard coat film excellent in wear resistance and flexibility are disclosed.

Japanese Patent No. 45747666 Japanese Patent No. 4160217 Japanese Patent No. 5320848 Japanese Patent No. 4569807

As described above, in recent years, the development of flexible mobile terminals capable of folding or folding an image display screen (display) has been promoted, and the surface protective film used for this type of image display screen also has an excellent surface. Along with hardness, durability that can be repeatedly bent practically, specifically, for example, 200,000 times or more is required.
However, none of the inventions described in Patent Documents 1 to 4 is intended for repeated bending, and it may be difficult to deal with them.

Therefore, it is an object of the present invention to provide a laminated film which not only has excellent surface hardness but also has excellent practical repetitive bending characteristics.

The present invention relates to the following.
<1> A base film, an anchor coat layer, and a mesh-shaped inorganic substance-containing layer are provided.
A laminated film in which the anchor coat layer and the inorganic substance-containing layer are provided on the surface of at least one side of the base film in this order.
_{<2> The laminated film according to <1> above, wherein the thickness (tac} ) of the anchor coat layer is 0.5 μm or more and 6 μm or less.
<3> The laminated film according to the thickness of the inorganic-containing layer _{(t in)} is 20nm or more 250nm or less above <1> or <2>.
<4> The inorganic-containing layer is a layer composed of silicon oxide represented by _{SiO x C y (1.4 ≦ x} ≦ 2.0,0 ≦ y ≦ 0.25), the <1> The laminated film according to any one of ~ <3>.
<5> The laminated film according to any one of <1> to <4> above, wherein the base film is a polyester film.
<6> The laminated film according to any one of <1> to <4> above, wherein the base film is a polyimide film.
<7> The laminate according to any one of <1> to <6> above, wherein the mesh-shaped inorganic substance-containing layer is formed by performing a CVD treatment on the inorganic substance-containing layer via a mask member having a mesh shape. Film manufacturing method.
<8> Described in any of the above <1> to <7>, wherein the radius (R: unit mm) at the bent portion is maintained at 3.0 or less and can be bent 200,000 times or more in the repeated bending evaluation. Laminated film.
<9> The laminated film according to any one of <1> to <8> above, which is used for a flexible display.

The laminated film of the present invention is a laminated film in which an anchor coat layer and an inorganic substance-containing layer having a mesh shape are laminated on the surface of a base film, and can have excellent surface hardness and excellent repeated bending characteristics.

Next, the present invention will be specifically described based on an example of the embodiment of the present invention, but the present invention is not limited to the embodiment described below.
<< Laminated film >>

The laminated film of the present invention includes a base film, an anchor coat layer, and a mesh-shaped inorganic substance-containing layer, and the anchor coat layer and the inorganic substance-containing layer are provided on the surface of at least one side of the base film in this order.
Since the laminated film of the present invention has a structure in which the inorganic substance-containing layer has a mesh shape, flexibility can be imparted by dispersing the stress applied to the inorganic substance-containing layer at the time of bending. Further, by interposing an anchor coat layer between the base film and the mesh-shaped inorganic substance-containing layer, it is possible to impart durability and exhibit excellent bending characteristics that do not break even when repeatedly bent. Further, the inorganic substance-containing layer can make the surface hardness excellent, and can improve the surface protection characteristics such as scratch prevention, stain resistance, and abrasion resistance.
Further, since the laminated film of the present invention can be imparted with transparency, it can be suitably used for a display, particularly a flexible display.

<Base film>
The base film (hereinafter referred to as "the base film") in the present invention is not limited in material and composition as long as it can obtain necessary and sufficient rigidity and repeated bending characteristics.

The base film may have a single-layer structure or a multi-layer structure.
When the base film has a multi-layer structure, it may have four or more layers as long as the gist of the present invention is not exceeded in addition to the two-layer and three-layer structure.

Regardless of whether the base film has a single-layer structure or a multi-layer structure, the main component resin of each layer is preferably polyester or polyimide. At this time, the "main component resin" means the resin having the highest content ratio among the resins constituting each layer of the base film, for example, 50% by mass or more of the resins constituting each layer of the base film. In particular, it is a resin that accounts for 70% by mass or more, especially 80% by mass or more (including 100% by mass).
In addition, each layer constituting this base film may contain other resin other than polyester or polyimide, or component other than resin, as long as the main component resin is polyester or polyimide.
Further, when the main component resin of each layer constituting the base film is polyester (in the case of a single layer, the single layer is in the case of a plurality of layers), and in the case of polyester, the base material is used. The film is referred to as a "polyester film", and when it is a polyimide, the base film thereof is referred to as a "polyimide film".

(polyester)
The base film is preferably a polyester film.
The polyester (referred to as “the present polyester”) as the main component resin of each layer constituting the present base film may be a homopolyester or a copolymerized polyester.

When the present polyester is made of a homopolyester, it is preferably obtained by polycondensing an aromatic dicarboxylic acid and an aliphatic glycol.
Examples of the aromatic dicarboxylic acid include terephthalic acid and 2,6-naphthalenedicarboxylic acid.
Examples of the aliphatic glycol include ethylene glycol, diethylene glycol, 1,4-cyclohexanedimethanol and the like.

When the present polyester is a copolymerized polyester, it is preferable that the polyester is obtained by polycondensing a dicarboxylic acid component and a glycol component. When the present polyester is a copolymerized polyester, examples of the dicarboxylic acid component include one or more of isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, sebacic acid and the like. can. On the other hand, examples of the glycol component include one or more of ethylene glycol, diethylene glycol, propylene glycol, butanediol, 1,4-cyclohexanedimethanol, neopentyl glycol and the like.

Specific examples of typical polyesters include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), and polybutylene terephthalate (PBN). Of these, PET and PEN are preferable in terms of handleability. Therefore, a preferable specific example of the polyester film is a polyethylene terephthalate film or a polyethylene naphthalate film.
When the main component resin of each layer constituting the base film is polyethylene terephthalate (in the case of a single layer, the single layer is in the case of a plurality of layers), for example, the film. Is referred to as "polyethylene terephthalate film". The same applies when the other resin is the main component resin.

(Polyimide)
As the base film, a polyimide film is also suitable in addition to the polyester film. Examples of the method for synthesizing the polyimide used for the base film include a method of polyamic acid polymerization of diamine and dianhydride, particularly aromatic dianhydride and aromatic diamine at a ratio of 1: 1 and then imidization. NS.
Examples of the aromatic dianhydride include 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA), 4- (2,5-dioxo tetrahydrofuran-3-yl) -1, 2,3,4-Tetrahydronaphthalene-1,2-dicarboxylic acid dianhydride (TDA), pyromellitic acid dianhydride (1,2,4,5-benzenetetracarboxylic acid dianhydride, PMDA), benzophenone tetra Examples thereof include carboxylic acid dianhydride (BTDA), biphenyltetracarboxylic acid dianhydride (BPDA), and biscarboxyphenyldimethylsilane dianhydride (SiDA). These may be used alone or in combination of two or more.
Examples of the aromatic diamine include oxydianiline (ODA), p-phenylenediamine (pPDA), m-phenylenediamine (mPDA), p-methylenedianiline (pMDA), m-methylenedianiline (mMADA), and the like. Bistrifluoromethylbenzidine (TFDB), cyclohexanediamine (13CHD, 14CHD), bisaminohydroxyphenylhexafluoropropane (DBOH) and the like are exemplified. These may be used alone or in combination of two or more.

(Other resin components)
Each layer constituting the base film may contain a resin other than polyester and polyimide as a main component resin. Examples of the main component resin in this case include epoxy, polyarylate, polyether sulfone, polycarbonate, polyether ketone, polysulphon, polyphenylene sulfide, polyester liquid crystal polymer, triacetyl cellulose, cellulose derivative, polypropylene, polyamides, and poly. Cycloolefins and the like can be exemplified.

The base film may contain particles for the purpose of forming an uneven structure on the film surface to impart various functions and for the main purpose of preventing scratches in each step. The type of the particles is not particularly limited as long as the particles can be easily slippery. For example, inorganic particles such as silica calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, magnesium phosphate, kaolin, aluminum oxide, titanium oxide, acrylic resin, styrene resin, urea resin, phenol resin, epoxy resin, benzoguanamine resin. Organic particles such as, etc. can be mentioned. These may be used alone or in combination of two or more of them. Further, during the polyester production process, precipitated particles in which a part of a metal compound such as a catalyst is precipitated and finely dispersed can also be used.
The shape of the particles is not particularly limited. For example, it may be spherical, lumpy, rod-shaped, flat-shaped, or the like. Further, the hardness, specific gravity, color and the like of the particles are not particularly limited. Two or more kinds of these series of particles may be used in combination, if necessary.

The average particle size of the particles is preferably 5 μm or less, more preferably 0.01 μm or more and 3 μm or less, and further preferably 0.5 μm or more and 2.5 μm or less. By setting the thickness to 5 μm or less, it is possible to prevent the surface roughness of the base film from becoming too rough, and to prevent problems from occurring when forming the anchor coat layer and the inorganic substance-containing layer in the subsequent step.
The average particle size of the particles can be obtained as an average value by arbitrarily selecting 10 or more particles existing in the base film by a scanning electron microscope (SEM) and measuring the diameter of each particle. .. At that time, in the case of non-spherical particles, the average value of the longest diameter and the shortest diameter ((minor diameter + major diameter) / 2) can be measured as the diameter of each particle.

The content of the particles is preferably 5% by mass or less, more preferably 0.0003% by mass or more and 3% by mass or less, and further preferably 0.01% by mass or more and 2% by mass with respect to 100% by mass of the base film. It is as follows. By setting the particle content in such a range, it is possible to achieve both slipperiness and transparency of the film.

The method of adding the particles to the base film is not particularly limited, and a conventionally known method can be adopted. For example, it can be added at any stage in the production of polyester. It is preferable to add the ester after the esterification or transesterification reaction is completed.

Additives such as conventionally known antioxidants, antistatic agents, heat stabilizers, lubricants, dyes, pigments, and ultraviolet absorbers can be added to the base film, if necessary.

The thickness of the base film is not particularly limited as long as it can be formed as a film, but is preferably 12 μm or more and 250 μm or less, more preferably 25 μm or more and 250 μm or less, and further preferably 50 μm or more and 200 μm or less. be.

The base film can be formed, for example, by forming a resin composition into a film shape by a melt film forming method or a solution film forming method. In the case of a multi-layer structure, co-extrusion may be performed. Further, it may be uniaxially stretched or biaxially stretched, and a biaxially stretched film is preferable from the viewpoint of rigidity.

(Characteristics of base film)
The tensile elastic modulus (JIS K 7161) of the base film is preferably 2 GPa or more, more preferably 8 GPa or less, and more preferably 3 GPa or more, from the viewpoint of obtaining necessary and sufficient rigidity and repeated bending characteristics. Further, 7 GPa or less is more preferable, and 5 GPa or less is more preferable.
As the tensile elastic modulus, a value obtained by pulling the base film in the MD direction and measuring it is adopted. However, when the MD direction of the base film cannot be determined, the tensile elastic modulus in the direction in which the tensile elastic modulus becomes the maximum value may be adopted.

<Anchor coat layer>
The anchor coat layer (hereinafter, referred to as “the present anchor coat layer”) in the present invention is also a layer for enhancing the adhesiveness between the base film and the inorganic substance-containing layer. In addition, the anchor coat layer has both durability and flexibility, which are contradictory characteristics. More specifically, the anchor coat layer repeats the laminated film even after the inorganic substance-containing layer having a mesh shape is laminated after ensuring the durability when the inorganic substance-containing layer is provided on the anchor coat layer. Improves bending characteristics.

<Anchor coat layer composition>
The anchor coat layer composition for forming the anchor coat layer preferably contains a curable compound. In addition to the curable compound, the anchor coat layer composition preferably contains a photopolymerization initiator, particles, a cross-linking agent, a solvent, and other components, if necessary. Each will be described below.

(Curable compound)
The curable compound may be any compound that can be cured, but is preferably a photopolymerizable compound having a carbon-carbon double bond such as a vinyl group and a (meth) acryloyl group. The resin contained in the anchor coat layer is preferably an acrylic resin, and therefore the curable compound more preferably contains a compound having a (meth) acryloyl group. When the curable compound contains a compound having a (meth) acryloyl group, the cured resin becomes an acrylic resin.
The curable compound may consist of one or more selected from the group consisting of crosslinkable monomers, acrylic acid esters, methacrylic acid esters, and urethane (meth) acrylates, and among them, excellent surface hardness and repetition. From the viewpoint of achieving both bending characteristics, those containing a mixture of two or more selected from these are preferable.
The crosslinkable monomer, acrylic acid ester, and methacrylic acid ester are compounds other than urethane (meth) acrylate. Further, the (meth) acryloyl group means one or both of an acryloyl group and a methacryloyl group, and other similar terms are also used.

Among the above, it is a comixture consisting of at least two kinds selected from crosslinkable monomers and (meth) acrylic acid esters from the viewpoint of handleability, industrial availability, and cost. Is preferable.
As described above, when at least two types of monomers (a / b) are used, assuming that the blending amounts (parts by mass) of each monomer are a and b, the blending ratio (a / b) is the mass ratio. The range is preferably 90/10 to 10/90, more preferably 80/20 to 40/60, and more preferably 70/30 to 40/60.

Further, it is also preferable to use urethane (meth) acrylate as the curable compound. By using urethane (meth) acrylate, it becomes easy to achieve both durability and flexibility, and it becomes easy to obtain a laminated film having excellent repeated bending characteristics. When urethane (meth) acrylate is used, the content of urethane (meth) acrylate is preferably 50 to 100% by mass, preferably 60 to 95% by mass, based on the curable compound contained in the anchor coat layer composition. More preferably, it is more preferably 70 to 90% by mass.
The curable compound used in combination with the urethane (meth) acrylate may be any of a crosslinkable monomer, acrylic acid esters, and methacrylic acid esters, but a crosslinkable monomer is preferable.

(Crosslinkable monomer)
The crosslinkable monomer refers to a monomer having two or more polymerizable functional groups in one molecule.
Examples of the crosslinkable monomer include allyl acrylate, allyl methacrylate, 1-acryloxy-3-butene, 1-methacryloxy-3-butene, 1,2-diacryloxy-ethane, 1,2-dimethacrylate-ethane, and the like. 1,2-Diacryloxy-propane, 1,3-diacryloxy-propane, 1,4-diacryloxy-butane, 1,3-dimethacryloxy-propane, 1,2-dimethacryloxy-propane, 1,4-dimethacryloxy-butane, triethylene Glycol dimethacrylate, polyethylene glycol diacrylate, 1,6-hexanediol dimethacrylate, 1.9-nonanediol dimethacrylate, triethylene glycol diacrylate, 1,6-hexanediol diacrylate, 1.9-nonanediol diacrylate , Divinylbenzene, 1,4-pentadiene, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate and the like. These may be used alone or in combination of two or more.

(Acrylic acid esters)
Examples of acrylic acid esters include monomers having one polymerizable functional group in one molecule. Specific examples of acrylic acid esters include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, and tert-butyl acrylate. Acrylic acid acyclic alkyl esters such as amyl acrylate, isoamyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, pentadecyl acrylate, dodecyl acrylate; cyclic alkyl acrylates such as cyclohexyl acrylate and isobornyl acrylate. Acrylic acid aryl esters such as phenyl acrylate and naphthyl acrylate; functional group-containing acrylic acid acyclic alkyl esters such as 2-hydroxyethyl acrylate, 2-methoxyethyl acrylate, and glycidyl acrylate can be exemplified. can.

(Methyl ester type)
Examples of the methacrylic acid ester include a monomer having one polymerizable functional group in one molecule. Specific examples of the above-mentioned methacrylate esters include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, and tert-methacrylate. Acyclic alkyl esters of methacrylic acid such as butyl, amyl methacrylate, isoamyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, pentadecyl methacrylate, dodecyl methacrylate; cyclic methacrylate such as cyclohexyl methacrylate and isobornyl methacrylate. Alkyl esters; aryl methacrylate esters such as phenyl methacrylate; functional group-containing non-cyclic alkyl esters of methacrylate such as 2-hydroxyethyl methacrylate, 2-methoxyethyl methacrylate, and glycidyl methacrylate can be exemplified.
The above-mentioned (meth) acrylic acid esters may be used alone or in combination of two or more.

(Urethane (meth) acrylate)
Urethane (meth) acrylate has a urethane bond in the molecule and has a (meth) acryloyl group. Urethane (meth) acrylate is obtained by reacting polyisocyanate with (meth) acrylate having a hydroxyl group, for example, or isocyanate group-containing urethane obtained by reacting a polyol and polyisocyanate under a condition of excess isocyanate group. Some are obtained by reacting a prepolymer with (meth) acrylates having a hydroxyl group. Alternatively, a hydroxyl group-containing urethane prepolymer obtained by reacting a polyol and a polyisocyanate under a condition of excess hydroxyl group can be obtained by reacting with (meth) acrylates having an isocyanate group. The urethane (meth) acrylate may be a mixture of two or more of these.
Urethane (meth) acrylate is generally an oligomer, for example, having a weight average molecular weight of 1000 to 50,000, preferably 2000 to 20000. Further, urethane (meth) acrylate is preferably polyfunctional.
The above weight average molecular weight is a weight average molecular weight converted to a standard polystyrene molecular weight. For example, in high performance liquid chromatography (manufactured by Japan Waters, "Waters 2695 (main body)" and "Waters 2414 (detector)"), a column: ShodexGPCKF-806L (exclusion limit molecular weight: 2 × 10 ^7, separation range: 100 to 2 × 10 ^7, theoretical plate number: 10,000 plates / the filler material: styrene - divinylbenzene copolymer, filler particle size: It can be measured by using three series of 10 μm).

Examples of the polyisocyanate used for urethane (meth) acrylate include aromatic diisocyanates, aliphatic diisocyanates, alicyclic diisocyanates, and isocyanate compounds having an isocyanurate skeleton obtained by isocyanurateizing these diisocyanates. Be done.
Examples of the aromatic diisocyanate include tolylene diisocyanate, diphenylmethane diisocyanate, polyphenylmethane polyisocyanate, modified diphenylmethane diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, phenylenedi isocyanate, naphthalene diisocyanate and the like. Examples of the aliphatic diisocyanate include hexamethylene diisocyanate, pentamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, and lysine triisocyanate. Examples of the alicyclic diisocyanate include hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, norbornene diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, and 1,4-bis (isocyanatomethyl). ) Cyclohexane and the like.
Among the above, it is preferable that the isocyanate compound has an isocyanurate skeleton. One type of polyisocyanate may be used alone, or two or more types may be used in combination.

Examples of (meth) acrylates having a hydroxyl group used for urethane (meth) acrylate include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 4 -Hydroxybutyl (meth) acrylate, hydroxyalkyl (meth) acrylate such as 6-hydroxyhexyl (meth) acrylate, 2-hydroxyethylacryloyl phosphate, 2- (meth) acryloyloxyethyl-2-hydroxypropylphthalate, caprolactone modification 2-Hydroxyethyl (meth) acrylate, dipropylene glycol (meth) acrylate, fatty acid-modified-glycidyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, 2-hydroxy-3- (meth) ) A (meth) acrylate-based compound containing one ethylenically unsaturated group such as acryloyloxypropyl (meth) acrylate; ethylene such as glycerindi (meth) acrylate and 2-hydroxy-3-acryloyl-oxypropyl methacrylate. (Meta) acrylate-based compound containing two sex unsaturated groups; pentaerythritol tri (meth) acrylate, caprolactone-modified pentaerythritol tri (meth) acrylate, ethylene oxide-modified pentaerythritol tri (meth) acrylate, dipentaerythritol penta (dipentaerythritol penta (meth) acrylate. Examples thereof include (meth) acrylate compounds containing three or more ethylenically unsaturated groups such as meta) acrylate, caprolactone-modified dipentaerythritol penta (meth) acrylate, and ethylene oxide-modified dipentaerythritol penta (meth) acrylate.
Among these, (meth) acrylate compounds containing two or three or more ethylenically unsaturated groups are preferable.
The (meth) acrylates having a hydroxyl group can be used alone or in combination of two or more.

Examples of the polyol used for urethane (meth) acrylate include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, neopentyl glycol, 1,2-butanediol, 1,3-butanediol, and 2,3-butane. Diol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,8-octanediol, 1,9-nonanediol, 2, 2-Dimethylol heptane, trimethylene glycol, 1,4-tetramethylene glycol, dipropylene glycol, 1,3-tetramethylenediol, 2-methyl-1,3-trimethylenediol, 2,4-diethyl-1, 5-Pentamethylenediol, hydrogenated bisphenol A, hydroxyalkylated bisphenol A, 1,4-cyclohexanedimethanol, 1,4-cyclohexanediol, 2,2,4-trimethyl-1,3-pentanediol, N, N Low molecular weight diols such as -bis- (2-hydroxyethyl) dimethylhydantin; polyether polyols such as polytetramethylene glycol diols, polyester polyols, polycarbonate polyols, polyolefin polyols, polybutadiene polyols, (meth) acrylics Examples thereof include high molecular weight polyols such as system-based polyols, polycaprolactone-based polyols, polysiloxane-based polyols, and polyurethane-based polyols. The polyol may be used alone or in combination of two or more.

(Photopolymerization initiator)
When the anchor coat layer composition is photocured, it is preferable to add a photopolymerization initiator.
The photopolymerization initiator is not particularly limited, and examples thereof include a ketone-based photopolymerization initiator and an amine-based photopolymerization initiator. Specifically, for example, benzophenone, Michler's ketone, 4,4'-bis (diethylamino) benzophenone, xanthone, thioxanthone, isopropylxanthone, 2,4-diethylthioxanthone, 2-ethylanthraquinone, acetophenone, 2-hydroxy-2-methylpro. Piophenone, 2-Hydroxy-2-methyl-4'-isopropylpropiophenone, 1-hydroxycyclohexylphenylketone, isopropylbenzoin ether, isobutylbenzoin ether, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2- Phenylacetophenone, camphorquinone, benzanthron, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) − Butanone-1, 4-dimethylaminobenzoate ethyl, 4-dimethylaminobenzoate isoamyl, 4,4′-di (t-butylperoxycarbonyl) benzophenone, 3,4,4′-tri (t-butylperoxycarbonyl) ) Benzophenone, 3,3', 4,4'-tetra (t-butylperoxycarbonyl) benzophenone, 3,3', 4,4'-tetra (t-hexylperoxycarbonyl) benzophenone, 3,3'-di ( Methoxycarbonyl) -4,4'-di (t-butylperoxycarbonyl) benzophenone, 3,4'-di (methoxycarbonyl) -4,3'-di (t-butylperoxycarbonyl) benzophenone, 4,4'- Di (methoxycarbonyl) -3,3'-di (t-butylperoxycarbonyl) benzophenone, 1,2-octanedione, 1- [4- (phenylthio) phenyl]-, 2- (o-benzoyloxime), 2 -(4'-methoxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 2- (3', 4'-dimethoxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 2- (2', 4'-dimethoxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 2- (2'-methoxystyryl) -4,6-bis (trichloromethyl) -s-triazine , 2- (4'-Pentyloxystyryl) -4,6-bis (trichloromethyl) -s-triazine, 4- [pn, N-di (ethoxycarbonylmethyl)]-2,6-di (trichloromethyl) Methyl) -s-triazine, 1 , 3-bis (trichloromethyl) -5- (2'-chlorophenyl) -s-triazine, 1,3-bis (trichloromethyl) -5- (4'-methoxyphenyl) -s-triazine, 2- (p) -Dimethylaminostyryl) benzoxazole, 2- (p-dimethylaminostyryl) benzthiazole, 2-mercaptobenzothiazole, 3,3'-carbonylbis (7-diethylaminocoumarin), 2- (o-chlorophenyl) -4, 4', 5,5'-Tetraphenyl-1,2'-biimidazole, 2,2'-bis (2-chlorophenyl) -4,4', 5,5'-tetrakis (4-ethoxycarbonylphenyl)- 1,2'-biimidazole, 2,2'-bis (2,4-dichlorophenyl) -4,4', 5,5'-tetraphenyl-1,2'-biimidazole, 2,2'-bis (2,2'-bis ( 2,4-Dibromophenyl) -4,4', 5,5'-tetraphenyl-1,2'-biimidazole, 2,2'-bis (2,4,6-trichlorophenyl) -4,4' , 5,5'-Tetraphenyl-1,2'-biimidazole, 3- (2-methyl-2-dimethylaminopropionyl) carbazole, 3,6-bis (2-methyl-2-morpholinopropionyl) -9- n-dodecylcarbazole, 1-hydroxycyclohexylphenylketone, bis (η5-2,4-cyclopentadiene-1-yl) -bis (2,6-difluoro-3- (1H-pyrrole-1-yl) -phenyl) Examples thereof include titanium, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, and 2,4,6-trimethylbenzoyldiphenylphosphine oxide. Only one kind of these photopolymerization initiators may be used, or two or more kinds thereof may be used.

Further, a sensitizer may be used in combination with the photopolymerization initiator, if necessary. Specific examples of the sensitizer include aliphatic amines such as n-butylamine, triethylamine, and ethyl p-dimethylaminobenzoate, and aromatic amines.

The content of the photopolymerization initiator is preferably in the range of 1 to 10 parts by mass, more preferably in the range of 1 to 5 parts by mass with respect to 100 parts by mass of the curable compound.
When the content of the photopolymerization initiator is 1 part by mass or more, the desired polymerization initiation effect can be obtained, and when the content of the photopolymerization initiator is 10 parts by mass or less, the yellow color of the anchor coat layer is obtained. The change can be suppressed. The photopolymerization initiator and the sensitizer are preferably used in a proportion of 20% by mass or less based on the solid content of the photocurable composition.

(particle)
The anchor coat layer composition may contain particles to improve slipperiness and blocking. Examples of the particles include inorganic particles such as silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, magnesium phosphate, kaolin, aluminum oxide, titanium oxide, acrylic resin, styrene resin, urea resin, and phenol resin. Examples thereof include organic particles such as epoxy resin and benzoguanamine resin. These may be used alone or in combination of two or more of them.

(Crosslinking agent)
From the viewpoint of improving chemical resistance or durability, the anchor coat layer composition may contain a cross-linking agent. The cross-linking agent referred to here means a cross-linking agent other than the above-mentioned cross-linking monomer.
Examples of the cross-linking agent include an oxazoline compound, an isocyanate compound, an epoxy compound, a melamine compound, a carbodiimide compound and the like. Above all, from the viewpoint of improving adhesion, it is more preferable to use at least one of an oxazoline compound or an isocyanate compound.

The above-mentioned oxazoline compound used as a cross-linking agent is a compound having an oxazoline group in the molecule, and a polymer containing an oxazoline group is particularly preferable, and it is produced by polymerization of an addition-polymerizable oxazoline group-containing monomer alone or with another monomer. be able to.
Examples of the addition-polymerizable oxazoline group-containing monomer include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, and 2-isopropenyl-2-. Oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline and the like can be mentioned, and one or a mixture of two or more thereof can be used. .. Among them, 2-isopropenyl-2-oxazoline is suitable because it is easily available industrially.
The other monomer is not limited as long as it is a monomer copolymerizable with the addition polymerizable oxazoline group-containing monomer, and is, for example, an alkyl (meth) acrylate (the alkyl group is a methyl group, an ethyl group, an n-propyl group, or an isopropyl). (Meta) acrylic acid esters such as group, n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group); acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid , Unsaturated carboxylic acids such as styrene sulfonic acid and salts thereof (sodium salt, potassium salt, ammonium salt, tertiary amine salt, etc.); unsaturated nitriles such as acrylonitrile and methacrylonitrile; (meth) acrylamide, N- Alkyl (meth) acrylamide, N, N-dialkyl (meth) acrylamide, (alkyl groups include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, 2 -Unsaturated amides such as (ethylhexyl group, cyclohexyl group, etc.); Vinyl esters such as vinyl acetate and vinyl propionate; Vinyl ethers such as methyl vinyl ether and ethyl vinyl ether; α-olefins such as ethylene and propylene; Vinyl chloride, Halogen-containing α, β-unsaturated monomers such as vinylidene chloride; α, β-unsaturated aromatic monomers such as styrene and α-methylstyrene can be mentioned, and one or more of these monomers can be used. Can be used.

From the viewpoint of improving adhesion, the amount of oxazoline groups in the oxazoline compound is preferably 0.5 to 10 mmol / g, particularly 1 mmol / g or more or 9 mmol / g or less, and among them, 3 mmol / g or more or 8 mmol / g or less. Among them, it is more preferably 4 mmol / g or more or 6 mmol / g or less.

The isocyanate compound used as a cross-linking agent is, for example, an isocyanate or a compound having an isocyanate derivative structure typified by blocked isocyanate.
The isocyanate has, for example, aromatic isocyanates such as tolylene diisocyanate, xylylene diisocyanate, methylene diphenyl diisocyanate, phenylenedi isocyanate and naphthalene diisocyanate, and aromatic rings such as α, α, α', α'-tetramethylxylylene diisocyanate. Aliphatic isocyanates such as aliphatic isocyanates, methylene diisocyanates, propylene diisocyanates, lysine diisocyanates, trimethylhexamethylene diisocyanates, hexamethylene diisocyanates, cyclohexanediisocyanates, methylcyclohexanediisocyanates, isophorone diisocyanates, methylenebis (4-cyclohexylisocyanates), isopropyridene dicyclohexyldiisocyanates and the like. The alicyclic isocyanate of the above can be exemplified. In addition, polymers and derivatives such as burettes, isocyanurates, uretdiones, and carbodiimides of these isocyanates can also be mentioned. These may be used alone or in combination of two or more. Among the above isocyanates, aliphatic isocyanates or alicyclic isocyanates are preferable as measures against yellowing due to ultraviolet irradiation.

When used in the state of blocked isocyanate, the blocking agent includes, for example, phenolic compounds such as heavy sulfites, phenol, cresol and ethylphenol, and alcoholic compounds such as propylene glycol monomethyl ether, ethylene glycol, benzyl alcohol, methanol and ethanol. Compounds, active methylene compounds such as methyl isobutanoyl acetate, dimethyl malonate, diethyl malonate, methyl acetoacetate, ethyl acetoacetate, acetylacetone, mercaptan compounds such as butyl mercaptan and dodecyl mercaptan, ε-caprolactam, δ-valerolactam, etc. Lactam compounds, amine compounds such as diphenylaniline, aniline, ethyleneimine, acetanilide, acid amide compounds of acetate amide, formaldehyde, acetoaldoxime, acetone oxime, methyl ethyl ketone oxime, cyclohexanone oxime and other oxime compounds can be mentioned. These can be used alone or in combination of two or more.

The isocyanate compound may be used alone, or may be used as a mixture or a bond with various polymers. From the viewpoint of improving the dispersibility and crosslinkability of the isocyanate compound, it is preferable to use a mixture or a bond with a polyester resin or a urethane resin.

The epoxy compound used as a cross-linking agent is a compound having an epoxy group in the molecule, and is, for example, a condensate of epichlorohydrin and a hydroxyl group or amino group such as ethylene glycol, polyethylene glycol, glycerin, polyglycerin, or bisphenol A. Examples thereof include polyepoxy compounds, diepoxy compounds, monoepoxy compounds, and glycidylamine compounds.
Examples of the polyepoxy compound include sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, triglycidyltris (2-hydroxyethyl) isocyanate, glycerol polyglycidyl ether, and trimethylolpropane. Examples of the polyglycidyl ether and the diepoxy compound include neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, resorcin diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, and propylene glycol diglycidyl ether. , Polypropylene glycol diglycidyl ether, Polytetramethylene glycol diglycidyl ether, Monoepoxy compounds include, for example, allyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenylglycidyl ether, glycidylamine compounds N, N, N', N ′ -Tetraglycidyl-m-xylylene diamine, 1,3-bis (N, N-diglycidylamino) cyclohexane and the like can be mentioned. From the viewpoint of improving adhesion, a polyether epoxy compound is preferable. Further, as the amount of the epoxy group, a polyepoxy compound having trifunctional or higher functionalities is preferable to bifunctional.

The above-mentioned melamine compound used as a cross-linking agent is a compound having a melamine skeleton in the compound. , And mixtures thereof.
As the alcohol used for etherification, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butanol, isobutanol and the like are preferably used. Further, the melamine compound may be either a monomer or a multimer of a dimer or more, or a mixture thereof may be used. Further, a type in which urea or the like is copolymerized with a part of melamine, or a catalyst can be used in combination to improve the reactivity of the melamine compound.

(Carbodiimide compound)
The carbodiimide compound used as a cross-linking agent is a compound having a carbodiimide structure, and is a compound having one or more carbodiimide structures in the molecule. A polycarbodiimide-based compound having two or more in the molecule is more preferable for better adhesion and the like.
This carbodiimide compound can be synthesized by a conventionally known technique, and a condensation reaction of a diisocyanate compound is generally used. The diisocyanate compound is not particularly limited, and either aromatic or aliphatic type can be used. Specifically, toluene diisocyanate, xylene diisocyanate, diphenylmethane diisocyanate, phenylenedi isocyanate, naphthalene diisocyanate, etc. Examples thereof include hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, dicyclohexyldiisocyanate, and dicyclohexylmethane diisocyanate.

The content of the carbodiimide group contained in the carbodiimide compound is the carbodiimide equivalent (weight [g] of the carbodiimide compound for giving 1 mol of the carbodiimide group), preferably 100 to 1000, and more than 250 or 800 or less. Among them, it is more preferably 300 or more or 700 or less. By using it in the above range, the durability of the coating film is improved.

When the anchor coat layer composition contains a cross-linking agent, the content of the cross-linking agent in the anchor coat layer composition is 10 parts by mass or more with respect to 100 parts by mass of the curable compound from the viewpoint of obtaining good coating strength. It is preferably 20 parts by mass or more, and more preferably 25 parts by mass or more. On the other hand, from the viewpoint of obtaining good adhesion between the films, it is preferably 70 parts by mass or less, more preferably 60 parts by mass or less, and more preferably 40 parts by mass or less.

(solvent)
Examples of the solvent include ketone solvents such as methyl ethyl ketone, methyl propyl ketone, methyl isobutyl ketone, diisobutyl ketone, cyclohexanone, diacetone alcohol and acetone; alcohol solvents such as pentanol, hexanol, heptanol and octanol; ethylene glycol monoethyl. Ether-based solvents such as ether, ethylene glycol monobutyl ether, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate; methyl acetate, ethyl acetate, butyl acetate, methoxybutyl acetate, amyl acetate, propyl acetate, ethyl lactate, methyl lactate, Ester-based solvents such as butyl lactate; organic solvents such as hydrocarbon solvents such as toluene, xylene, solventnaphtha, hexane, cyclohexane, ethylcyclohexane, methylcyclohexane, heptane, octane, and decane can be exemplified. These organic solvents may be used alone or in combination of two or more. Further, the anchor coat layer composition may contain water as a solvent, or a mixture of an organic solvent and water may be used as a solvent. When the anchor coat layer composition contains a solvent, the solid component is diluted with the solvent, so that the coatability is improved. The solvent may be added to the anchor coat layer composition so that the solid content concentration is, for example, about 0.1 to 50% by mass.

(Other ingredients)
In order to improve the water solubility and water dispersibility of the polycarbodiimide compound, to the extent that the gist of the present invention is not impaired, a surfactant may be added, or a polyalkylene oxide, a quaternary ammonium salt of a dialkylamino alcohol, or a hydroxy may be added. It is optionally possible to add a hydrophilic monomer such as an alkyl sulfonate.
When the above-mentioned anchor coat layer composition contains a cross-linking agent, a component for promoting cross-linking, for example, a cross-linking catalyst may be added at the same time.

(Method of forming anchor coat layer)
The anchor coat layer can be formed on the base film by applying the anchor coat layer composition to the base film and then, if necessary, heating, irradiating with active energy rays, or the like.
As a method of applying the anchor coat layer composition to the base film, conventionally known coating methods such as reverse gravure coat, direct gravure coat, roll coat, die coat, bar coat and curtain coat can be used. The heating (heat treatment) is not particularly limited, but may be performed on the coating film formed on the base film at, for example, 70 to 280 ° C. for 3 to 200 seconds.

The anchor coat layer can also be formed by in-line coating. However, the method for forming the anchor coat layer is not limited to the method for forming the anchor coat layer by in-line coating. When formed by in-line coating, the above series of compounds are dissolved or dispersed in a solvent, and a coating liquid having a solid content concentration of about 0.1 to 50% by mass is applied onto the base film. Is preferable.

The heating conditions for forming the anchor coat layer on the surface of the base film by offline coating are not particularly limited, and for example, 80 to 200 ° C. for 3 to 40 seconds, preferably 100 to 180 ° C. for 3 to 3 to It is preferable to perform heat treatment for 40 seconds as a guide.
On the other hand, when the anchor coat layer is formed by in-line coating, it is usually preferable to perform heat treatment at 70 to 280 ° C. for 3 to 200 seconds as a guide.
The in-line coating is a method of applying the anchor coat layer composition to the surface of the base film on the production line for manufacturing the base film. Further, the offline coating is a method of applying the anchor coat layer composition outside the system (outside the production line) once produced on the base film.

Further, regardless of the offline coating or the in-line coating, the anchor coat layer composition coated on the base film may be irradiated with active energy rays. For example, when the curable compound contains a photopolymerizable compound, it is preferable to perform activation energy ray irradiation.
As the active energy rays, in addition to far-ultraviolet rays, ultraviolet rays, near-ultraviolet rays, rays such as infrared rays, electromagnetic waves such as X-rays and γ-rays, electron beams, proton rays, neutron rays, etc. can be used. Ultraviolet irradiation is preferable because of its availability and price.
The dose of the active energy ray is not particularly limited, for example 100 to 2000 mJ / cm ^2, preferably may be irradiated with ultraviolet rays 300~1500mJ / cm ² of about integrated quantity of light.

Irradiation with active energy rays may be used in combination with heat treatment if necessary. When used in combination with heat treatment, the anchor coat layer composition coated on the surface of the base film is first dried by, for example, heat treatment as described above, and then the anchor coat layer composition is irradiated with active energy rays. It should be cured.
The surface of the base film on which the anchor coat layer is formed may be subjected to surface treatment such as corona treatment or plasma treatment in advance.

<Inorganic compound-containing layer with mesh shape>
The inorganic substance-containing layer having a mesh shape is mainly a layer for achieving both surface hardness and repeated bending characteristics. The inorganic substance-containing layer may be, for example, the outermost layer of the laminated film of the present invention.

The inorganic substance-containing layer is composed of an inorganic substance, particularly an inorganic oxide. The inorganic substance-containing layer is a layer containing an inorganic substance, particularly an inorganic oxide as a main component, and has excellent surface hardness, easy film formation, and excellent adhesion to an anchor coat layer. The main component means that the inorganic substance occupies 50% by mass or more, particularly 70% by mass or more, particularly 80% by mass or more, and 90% by mass or more of the inorganic substance-containing layer, and 100% by mass is occupied by the inorganic substance. May be good.

The inorganic substance-containing layer is preferably composed of a thin film containing at least one selected from diamond-like carbon, metals, metal oxides and metal nitrides. The metal referred to here also includes so-called metalloids such as silicon, boron, and germanium. From the viewpoint of adhesion to the anchor coat layer, silicon and aluminum are more preferable as the metal. Further, as the metal oxide or the metal nitride, it is preferable to use an oxide of silicon or aluminum, a nitride or a mixture thereof from the viewpoint of adhesion to the anchor coat layer.

The inorganic substance-containing layer comprises at least one inorganic compound selected from the group consisting of silicon oxide, silicon nitride, silicon nitride, silicon oxide, silicon oxide carbide, aluminum oxide, aluminum nitride, aluminum nitride and aluminum oxide. It is preferable to contain it. Of these, at least one silicon oxide selected from silicon oxide and silicon carbide is more preferable. Further, as the metal oxide or the metal nitride, those obtained by plasma decomposition of an organic compound may be used.

Inorganic-containing layer, from the viewpoint of a repeating bending characteristics _excellent, SiO _x C y; Table in (1.4 ≦ x ≦ 2.0,0.0 ≦ y ≦ 0.25 hereinafter also referred to as formula (1)) It is particularly preferable that the layer is composed of the silicon oxide to be formed. The composition can be confirmed by XPS analysis or the like. Among the above, x is preferably 1.6 or more. Further, y is preferably 0.01 or more, more preferably 0.05 or more, and preferably 0.20 or less.
When the value of x (lower limit value) becomes smaller, the gas permeability becomes smaller, but the silicon oxide film itself may become yellowish and the transparency may become lower, and the lower limit value or more is preferable.
In the above composition, the oxygen (O) component is an index of the degree of hydrophilicity of the obtained silicon oxide film itself. On the other hand, the carbon (C) component is an index of water repellency. The larger the value of x, the stronger the hydrophilicity. Normally, there is a tendency to increase the ratio of the oxygen (O) component in order to impart hydrophilicity, and the x value may be in the range of 1.4 or more.

In the present invention, the inorganic substance-containing layer may have a two-layer structure or may have a laminated structure of three or more layers. In the case of a laminated structure of two layers or three or more layers, each layer may be appropriately selected from the above-mentioned inorganic substances. By forming another inorganic substance-containing layer on the one layer of the inorganic substance-containing layer, it is possible to provide auxiliary support when the single layer of the inorganic substance-containing layer alone is insufficient.
Further, in the case of a laminated structure of two layers or three or more layers, it is preferable that any one layer is a layer composed of a silicon oxide represented by the above formula (1). Further, among them, the layer in contact with the anchor coat layer is more preferably a layer composed of the silicon oxide represented by the above formula (1) from the viewpoint of improving the repeatability. Further, all the layers may be layers composed of the silicon oxide represented by the above formula (1).

A silicon compound can be used as a raw material for forming an inorganic substance-containing layer composed of a silicon oxide. As the silicon compound, for example, when an inorganic substance-containing layer is formed by CVD described later, tetraethoxysilane (TEOS), tetramethoxysilane (TMS), tetramethylsilane (TMS), hexamethyldisiloxane (HMDSO), tetra. A relatively low molecular weight organic silane compound such as methyldisiloxane or methyltrimethoxysilane can be used. Among them, tetraethoxysilane (TEOS) and hexamethyldisiloxane (HMDSO) are preferable from the viewpoint of achieving both surface hardness and repeated bending characteristics.

<Mesh shape>
The inorganic substance-containing layer has a mesh shape, and one side of the laminated film may be composed of a portion coated by the inorganic substance-containing layer (coated portion) and a portion not coated (uncoated portion). Since the laminated film of the present invention can disperse stress at the time of bending due to the voids (uncoated portion) of the mesh-shaped inorganic substance-containing layer, it is possible to exhibit excellent repeated bending characteristics.

Any shape can be adopted as the mesh shape, and the mesh shape is not particularly limited, and examples thereof include a mesh shape in which fine line portions composed of uncovered portions intersect each other to form a lattice shape. The lattice is not limited to a square or rectangular lattice in which thin line portions intersect vertically, and may be an oblique lattice in which thin lines intersect at an inclination. In the mesh shape forming a grid shape, the covering portion has a minute quadrangular dot shape.
However, the mesh shape may be any form in which a plurality of dot-shaped coated portions surrounded by uncoated portions are formed and arranged at intervals. For example, a honeycomb structure in which the coated portions are hexagonal is also used. It may be a circular or oval mesh shape in which the covering portion is circular, oval, or the like, or a mesh shape in which dot-shaped covering portions are irregularly arranged.
Among the above, the mesh shape is preferably grid-like.
As described above, it can be said that the mesh-shaped inorganic substance-containing layer has a shape in which a plurality of dot-shaped covering portions are arranged along the plane direction. By forming a configuration in which a plurality of dot-shaped covering portions are arranged, the repeated bending characteristics are further improved.

The size of the mesh shape of the inorganic substance-containing layer can be defined by the number of meshes. The number of meshes is a unit that expresses the size of the mesh. The mesh shape of the inorganic substance-containing layer is, for example, 10 mesh or more, preferably 30 mesh or less, more preferably 50 mesh or more, and for example, 500 mesh or less, preferably 400 mesh or less, more preferably 350 mesh or less. be.

The wire diameter of the mesh shape of the inorganic substance-containing layer is not particularly limited, but is preferably 0.01 mm or more from the viewpoint of mesh manufacturing technology. The wire diameter is preferably 2 mm or less, more preferably 1 mm or less, and even more preferably 0.5 mm or less. The wire diameter of the mesh shape is the width of the uncovered portion when the mesh shape is formed by the uncoated portion as described above.
The opening of the mesh shape is preferably 0.04 mm or more. When the opening is 0.04 mm or more, it is possible to prevent problems such as the raw material not passing through the mask member when forming the inorganic substance-containing layer. The opening is preferably 8 mm or less, more preferably 5 mm or less, and even more preferably 1 mm or less. The opening represents the size of the covered portion (that is, the dots) when the mesh shape is formed by the uncoated portion as described above.
The maximum height difference of the mesh shape can be adjusted by, for example, adjusting the thickness when forming the mesh structure. However, the present invention is not limited to this.

In the above description, an example in which the uncovered portion constitutes a mesh has been described, but the covered portion itself may form a mesh. Since the specific contents of the mesh shape when the covering portion constitutes the mesh are as described above, the description thereof will be omitted.

On one side of the laminated film provided with the inorganic substance-containing layer, the coverage by the inorganic substance-containing layer is preferably 15% or more. When the coverage is 15% or more, a certain area or more on one side of the laminated film is covered with the inorganic substance-containing layer, and the surface hardness of the laminated film becomes good. From such a viewpoint, the coverage of the inorganic substance-containing layer is preferably 20% or more, more preferably 25% or more.
The coverage of the inorganic substance-containing layer is preferably 90% or less. When the coverage is 90% or less, it is possible to prevent the area ratio of the inorganic substance-containing layer from becoming too large, and prevent the flexibility from being lowered and the repeated bending characteristics from being lowered. From such a viewpoint, the coverage of the inorganic substance-containing layer is more preferably 85% or less, and further preferably 80% or less.

(Method of forming the inorganic substance-containing layer)
The inorganic substance-containing layer can be formed by, for example, a chemical vapor deposition method (CVD), a physical vapor deposition method (PVD), or the like, as described below, and among these, CVD is preferable.

The pressure for forming the inorganic substance-containing layer by CVD is preferably performed under reduced pressure in order to form a dense thin film, and the film formation rate, mesh structure formability, stable plasma can be generated, and impurities are mixed. From the viewpoint of suppressing the above, it is preferably 100 Pa or less, more preferably 1 Pa or more and 80 Pa or less, and further preferably 1 Pa or more and 60 Pa or less.
CVD may be performed by, for example, a plasma CVD method. Further, the inorganic substance-containing layer formed by CVD may be subjected to a cross-linking treatment by electron beam irradiation, if necessary, in order to improve water resistance and durability.

The pressure for forming the inorganic material-containing layer by PVD are inorganic-containing layer to be formed and the vacuum exhaust capacity, for example in terms of the degree of oxidation of the formed layer of _SiO x _{C y,} preferably 1 × 10 ^-7 to 1 Pa , More preferably 1 × 10 ^-6 to 1 × 10 ^-1 Pa or less, and even ^{more preferably 1 × 10 -4} or more and 1 × 10 ⁻² Pa or less. The partial pressure at the time of introduction of oxygen is preferably in the range of 10 to 90%, more preferably 20 to 80%, based on the total pressure.

The output conditions for forming the inorganic substance-containing layer are preferably 100 W or more and 1000 W or less, more preferably 100 W or more and 500 W or less, and further preferably 200 W or more and 500 W or less from the viewpoint of forming a more dense film.
When the plasma CVD method is used, the film thickness can be adjusted to an arbitrary film thickness by adjusting the output, the pressure of the raw material gas, the concentration, the plasma generation time, and the like.

The inorganic substance-containing layer can be obtained by arranging the mask member on the surface of the film base material and forming the inorganic substance-containing layer through the mask member by the above-mentioned CVD, PVD or the like. The material of the mask member is not particularly limited as long as it can withstand the environment at the time of film formation of the inorganic substance-containing layer, and for example, metals such as stainless steel, magnetic stainless steel, aluminum, copper, tungsten, molybdenum, titanium, nickel, and tantalum. Alternatively, it may be a resin such as nylon, polyester, Teflon (registered trademark), polyethylene, polypropylene, or the like.

The mask member preferably has a mesh shape. The mask member having a mesh shape may be composed of thin wire portions and may have a grid-like mesh shape in which gaps are formed between the thin wire portions, or a honeycomb structure is formed by the thin wire portions and the inside of the honeycomb is void. It may have a shape. Further, it may have a mesh shape in which a plurality of circles, ellipses, etc. are arranged as voids. At this time, for example, a plurality of voids may be arranged along two or more directions (for example, an arbitrary one direction along the plane direction and a direction perpendicular to the one direction).
When the mask member has the mesh shape as described above, as described above, the inorganic substance-containing layer forming the mesh shape can be formed by the uncoated portion.

The aperture ratio of the mask member is preferably 15% or more, more preferably 20% or more, further preferably 25% or more, further preferably 90% or less, more preferably 85% or less, still more preferably 80% or less. By setting the aperture ratio of the mask member within the above range, the coverage ratio of the inorganic substance-containing layer can be within the above range.
The number of meshes of the mask member, the wire diameter of the mesh shape, and the opening are the same as the mesh shape of the above-mentioned inorganic substance-containing layer, and the description thereof will be omitted.

For example, when a 100-mesh mask member is used, a 100-mesh mesh-like inorganic substance-containing layer can be formed, and for example, when a 350-mesh mask member is used, a 350-mesh mesh-like inorganic substance-containing layer can be formed.
Here, 100 mesh means that 100 meshes are lined up in 1 inch (25.4 mm). In the case of 100 mesh, the wire diameter is typically 0.1 mm, the opening is 0.154 mm, the aperture ratio in the mask member is 36.8%, and the coverage ratio of the inorganic substance-containing layer is also 36.8. It becomes%.
On the other hand, in the case of 350 mesh, the wire diameter is typically 0.03 mm, the opening is 0.043 mm, the aperture ratio is 34.7%, and the coverage ratio of the inorganic substance-containing layer is also 34.7. It becomes%.

<Thickness of inorganic substance-containing layer and anchor coat layer>
The present invention focuses on the combination of the mesh-shaped inorganic substance-containing layer and the anchor coat layer which is a base layer to be combined with the mesh-shaped inorganic substance-containing layer. While maintaining durability, it is also necessary to pay attention to the flexibility of the inorganic substance-containing layer laminated on the anchor coat layer. That is, it is necessary to achieve both durability and flexibility, which are contradictory characteristics. From such a viewpoint, the thickness ( _tac ) of the anchor coat layer is preferably set in the range of 0.1 μm or more and 6 μm or less, and the mesh. the thickness of the inorganic-containing layer having a shape _{(t in)} or equal to 20nm or 250nm or less. By setting the thickness range within these ranges, the desired flexibility can be obtained, and the underlying anchor coat layer has appropriate durability, so that the desired bending characteristics can be exhibited. Further, when the thickness of the anchor coat layer is 6 μm or less, the slipperiness is good, there is almost no peeling from the base film due to the internal stress of the anchor coat layer itself, and the thickness is 0.1 μm or more. For example, it is also preferable in that a uniform thickness can be maintained.

_{The thickness (tac} ) of the anchor coat layer is more preferably 0.2 μm or more and 6 μm or less, and further preferably 0.5 μm or more and 6 μm or less.
The thickness of the inorganic-containing layer _{(t in)} is more preferably 50nm or more 250nm or less, more preferably among them it is 80nm or more 250nm or less. When the thickness of the inorganic substance-containing layer is within such a range, it is possible to achieve both surface hardness and repeated bending characteristics at a high level.
The thickness of the anchor coat layer and the inorganic substance-containing layer is the thickness of the single layer in the case of a single layer, and the total thickness of the two or more layers in the case of a multi-layer structure of two or more layers. be.

<Physical characteristics of laminated film>
(Pencil hardness)
The laminated film having the above structure (hereinafter referred to as "the present laminated film") can have a surface hardness of the film, specifically, a pencil hardness of the surface of the mesh-like inorganic substance-containing layer of 2H or more.

(Repeated bending characteristics)
The laminated film having the above structure is provided with an anchor coat layer on the surface of the base film, and an inorganic substance-containing layer having a mesh shape is provided on the anchor coat layer to enhance practical repeatability. Can be done. Therefore, in the repeated bending evaluation, the radius (R: unit mm) at the bent portion is maintained at 3.0 or less, and the laminated film is bent 100,000 times or more, especially 150,000 times or more, and 200,000 times or more among them. It is possible. The fact that it can be bent means that cracks do not occur in the repeated bending evaluation.

(Haze of laminated film)
The haze of the laminated film is preferably 10% or less, more preferably 5% or less, still more preferably 3% or less. By setting the haze to 10% or less, light transmission can be improved, and it can be suitably used for display applications, especially as a flexible cover film. The haze can be set to be equal to or lower than the above upper limit value by having the base film, the anchor coat layer, and the inorganic substance-containing layer described above in the present laminated film.

<Thickness of laminated film>
By adjusting the overall thickness of the laminated film, it is possible to suppress the occurrence of wrinkles while ensuring the desired bending characteristics.
From this point of view, the total thickness of the laminated film is preferably 12 μm or more, more preferably 25 μm or more and 500 μm or less, and further preferably 38 μm or more and 250 μm or less.

<Use of laminated film>
As described above, the laminated film of the present invention has excellent repetitive bending characteristics while increasing the surface hardness. Therefore, it can be suitably used as a surface protective film or a constituent member inside various devices, and is particularly suitable as a flexible cover film. Further, the laminated film of the present invention is preferably used for display applications, particularly flexible displays, and is suitable for surface protective films for display applications, especially flexible cover films for displays, and has high industrial value. However, the use of this laminated film is not limited to these uses.

<<< Explanation of words >>>
In the present invention, the term "film" shall include the "sheet", and the term "sheet" shall include the "film".

In the present invention, when "X to Y" (X, Y are arbitrary numbers) is described, it means "X or more and Y or less" and "preferably larger than X" or "preferably more than Y" unless otherwise specified. It also includes the meaning of "small".
In addition, when "X or more" (X is an arbitrary number) is described, it includes the meaning of "preferably larger than X" and is described as "Y or less" (Y is an arbitrary number) unless otherwise specified. Unless otherwise specified, it also includes the meaning of "preferably smaller than Y".

Hereinafter, the present invention will be specifically described with reference to Examples. However, the present invention is not limited to the following examples.
The measurement method and evaluation method used in the present invention are as follows.

(1) Thickness of Anchor Coat Layer The surface of the anchor coat layer _{was dyed with RuO 4} and embedded in an epoxy resin. Thereafter, stained with sections RuO ₄ again created by ultramicrotomy, an anchor coat layer sectional TEM (Hitachi Ltd. High-Technologies "H-7650", the acceleration voltage 100 kV) was used for the measurement.

(2) Thickness of Inorganic Substance-Containing Layer The sample was prepared by an epoxy resin-embedded ultrathin section method, and measured with a cross-sectional TEM device (“JEM-1200EXII” manufactured by JEOL Ltd.) under the condition of an acceleration voltage of 120 kV.
As for the thickness of the inorganic substance-containing layer of 10 nm or less, it is difficult to obtain an accurate value even by the measurement by the cross-sectional TEM method. Therefore, a relatively thick inorganic substance-containing layer of 20 nm or more formed under the same film forming conditions is used. , The film formation rate per unit traveling speed is calculated by measuring by the cross-sectional TEM method, and the thickness when the film is formed at the traveling speed described in the examples is calculated.

(3) Elemental composition of inorganic substance-containing layer Using an XPS analyzer (“K-Alpha” manufactured by Thermo Fisher Scientific Co., Ltd.), the binding energy was measured by XPS (X-ray photoelectron spectroscopy), and Si2P, C1S, The elemental composition (at.%) Was calculated by converting from the peak area corresponding to N1S, O1S and the like. The carbon content of the inorganic substance-containing layer was evaluated by reading the value of the portion of the inorganic substance-containing layer on the XPS chart.

(4) The haze of the laminated film was measured using a film haze haze meter (NDH2000, manufactured by Nippon Denshoku Industries Co., Ltd.) according to JIS K7136.

(5) Pencil hardness (hard coat property)
The pencil hardness was evaluated with a pencil hardness tester (manufactured by Yasuda Seiki Co., Ltd.) under a load condition of 750 g in accordance with JIS K 5600-5-4. Based on the result, it was judged according to the following criteria.
(criterion)
A (good): Pencil hardness is 2H or more.
B (poor): Pencil hardness is less than 2H.

(6) Repeated bending evaluation Using a bending tester (DLDMLLH-FS manufactured by Yuasa System Co., Ltd.), a bending test was performed so that the inorganic substance-containing layer of the sample film (30 mm × 130 mm) was the outer surface, and the inorganic substance was obtained. The presence or absence of cracks on the surface provided with the containing layer was visually confirmed. In addition, the radius (R: unit mm) at the bent portion was also confirmed.
Then, the number of times of repeated bending was measured together with the radius (R), and based on the result, the determination was made according to the following criteria.
(criterion)
A (good): R = 3.0 or less was maintained, and repeated bending was possible 200,000 times without cracking.
B (poor): Cracks occurred when R = 3.0 or when the number of repeated bends was less than 200,000.

(7) Comprehensive evaluation Each laminated film obtained in Examples and Comparative Examples was judged according to the following judgment criteria.
(criterion)
A (good): Both the surface hardness and the repeated bending property are A.
B (poor): At least one of the surface hardness and the repeated bending property is B.

<Base film F1>
Mitsubishi Chemical Corporation: Polyethylene terephthalate biaxially stretched film (product name "Diafoil T612 type", thickness: 50 μm)

Example 1
Anchor coat layer composition AC prepared as described below is applied onto the base film F1.
After heating and drying at 90 ° C. for 1 minute, _{an anchor coat layer having a thickness (tac} ) of 5 μm was formed by irradiating with ultraviolet rays ^{of 400 mJ / cm 2 in an integrated light amount.}

(Preparation of Anchor Coat Layer Composition AC)
29.3 g (isocyanate group content: 21.0%) of hexamethylene diisocyanate trimer having an isocyanurate skeleton in a four-port flask equipped with a thermometer, a stirrer, a water-cooled condenser, and a nitrogen gas inlet. 0.05 mol), 70.7 g (0.15 mol) of a mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate (hydroxyl value 120 mgKOH / g), 2,6-di-tert-butyl cresol 0 as a polymerization inhibitor .06 g and 0.02 g of dibutyltin dilaurate as a reaction catalyst were charged and reacted at 60 ° C., and the reaction was terminated when the residual isocyanate group became 0.3% or less, and urethane acrylate (1) (weight average molecular weight was 10). , 500) 70 g and 30 g of pentaerythritol tetraacrylate (1) were obtained.

Isophorone diisocyanate 37.5 g (0.17 mol), polytetramethylene glycol diol 25.5 g (hydroxyl value 167 mgKOH / g; hydroxyl group) in a four-necked flask equipped with a thermometer, agitator, water-cooled condenser, and nitrogen gas inlet. Molecular weight calculated from valence 672; 0.04 mol), polyester triol 13.4 g (hydroxyl value 262 mgKOH / g; molecular weight calculated from hydroxyl value 642; 0.02 mol), and dibutyltin dilaurate 0.02 g as a reaction catalyst. It was charged and reacted at 80 ° C. When the residual isocyanate group became 11% or less, 23.6 g (0.2 mol) of 2-hydroxyethyl acrylate and 0.04 g of methoxyphenol as a polymerization inhibitor were further charged and reacted at 60 ° C. to cause the residual isocyanate group. The reaction was terminated when the content was 0.3% or less to obtain urethane acrylate (2) (weight average molecular weight: 3,400).
A mixture of 70 parts by mass of the mixture (1) and 30 parts by mass of urethane acrylate (2) was mixed to prepare a mixture of a photopolymerizable compound consisting of 79 parts by mass of urethane acrylate and 21 parts by mass of pentaerythritol tetraacrylate.
Next, 5 parts by mass of a photopolymerization initiator (Omnirad 184 manufactured by IGM RESINS BV) was added to 100 parts by mass of the obtained mixture of the photopolymerizable compounds, and methyl ethyl ketone was added so that the solid content became 30% by mass. The anchor coat layer composition AC was adjusted to.

(Formation of mesh-like inorganic substance-containing layer)
Next, using a high-speed sputtering device (“PD-220N” manufactured by SAMCO Corporation), tetraethoxysilane (TEOS) was introduced to set the partial pressure to 40 Pa, and the mask member was placed on the anchor coat layer. in performs CVD under vacuum of 40 Pa, on the anchor coat layer of the base film, the thickness _(t in) 100 nm of _{SiO x C y (x = 1.9} , y = 0.1) mesh of An inorganic substance-containing layer was formed.
As a result, a three-layer laminated film composed of a base film F1 (PET) / an anchor coat layer (AC) / an inorganic substance-containing layer (SiO _{x Cy) was obtained.}
The mask member was a mask having a square grid-like mesh, and had 100 meshes, a wire diameter of 0.1 mm, an opening of 0.154 mm, and an aperture ratio of 36.8%.

Example 2
A laminated film was obtained by producing in the same manner as in Example 1 except that the mesh pattern of the inorganic substance-containing layer was changed.
The mask member was a mask having a square grid-like mesh, and had 350 mesh, a wire diameter of 0.03 mm, an opening of 0.043 mm, and an aperture ratio of 34.7%.

Examples 3 and 4
A laminated film was obtained in the same manner as in Examples 1 and 2 except that the raw material for forming the inorganic substance-containing layer was changed as shown in Table 1. Incidentally, inorganic-containing layer _was a layer formed of a _{SiO x C y (x = 1.99} , y = 0.01).

Comparative Example 1
A two-layer laminated film composed of a base film / AC layer was obtained in the same manner as in Examples except that the mesh-like inorganic substance-containing layer was not formed.

Comparative Example 2
A two-layer laminated film composed of a _{base film F1 / CVD inorganic substance-containing layer (SiO x Cy} ) was obtained in the same manner as in Example 1 except that the anchor coat layer was not formed.

Comparative Example 3
A three-layer laminated film composed of a _{base film F1 / anchor coat layer / CVD inorganic substance-containing layer (SiO x Cy} ) in the same manner as in Example 1 except that the inorganic substance-containing layer is formed on the entire surface of the anchor coat layer. Got

<Evaluation result>
The characteristics of each resin molded product (laminated film) obtained in the above Examples and Comparative Examples are shown in Table 1 below.

Based on the above examples and the test results conducted by the inventors so far, the laminated film of the present invention having a structure in which an anchor coat layer and a mesh-like inorganic substance-containing layer are laminated on the surface of the base film is highly advanced. It was found that both surface hardness and repeated bending characteristics can be achieved at the level.

This laminated film has excellent surface hardness and practical repetitive bending characteristics, and can be suitably used as a surface protective film and a constituent member inside various devices. Further, since this laminated film can also have transparency, it can be suitably used for a surface protective film, particularly a surface protective film for a display, and particularly a flexible cover film for a flexible display.

Claims (9)

A base film, an anchor coat layer, and a mesh-shaped inorganic substance-containing layer are provided.
A laminated film in which the anchor coat layer and the inorganic substance-containing layer are provided on the surface of at least one side of the base film in this order. _{The laminated film according to claim 1, wherein the thickness (tac} ) of the anchor coat layer is 0.1 μm or more and 6 μm or less. The laminated film according to claim 1 or 2 thickness of the inorganic-containing layer _{(t in)} is 20nm or more 250nm or less. The inorganic-containing layer is a layer composed of silicon oxide represented by _{SiO x C y (1.4 ≦ x} ≦ 2.0,0.0 ≦ y ≦ 0.25), according to claim 1 to 3 The laminated film according to any one of the above. The laminated film according to any one of claims 1 to 4, wherein the base film is a polyester film. The laminated film according to any one of claims 1 to 4, wherein the base film is a polyimide film. The laminated film according to any one of claims 1 to 6, wherein the mesh-shaped inorganic substance-containing layer is formed by performing a CVD treatment on the inorganic substance-containing layer via a mask member having a mesh shape. The laminated film according to any one of claims 1 to 7, wherein the radius (R: unit mm) at the bent portion is maintained at 3.0 or less and can be bent 200,000 times or more in the repeated bending evaluation. The laminated film according to any one of claims 1 to 8, which is used for a flexible display.