WO2022249674A1

WO2022249674A1 - Layered body and method for manufacturing same, and image display device

Info

Publication number: WO2022249674A1
Application number: PCT/JP2022/012199
Authority: WO
Inventors: 由佳山▲崎▼; 佳史 ▲高▼見; 智剛梨木
Original assignee: 日東電工株式会社
Priority date: 2021-05-24
Filing date: 2022-03-17
Publication date: 2022-12-01
Also published as: KR20240011660A; JP2022179907A; TW202306761A

Abstract

A layered body (100) comprises a hard coat film in which a hard coat layer (11) is provided on one main surface of a film substrate (10), a primer layer (3) provided on the hard coat layer and in contact with the hard coat layer, and an inorganic thin film (5) provided on the primer layer and in contact with the primer layer. The inorganic thin film may be an antireflection layer comprising a layered body of a plurality of thin films having different refractive indices. The primer layer is a metal oxide thin film and includes an oxide of a specific metal element such as Sc, Y, Ti, Zr, V, Nb, Cr, Mo, W, Tc, Re, Ru, Os, Al, or Sn.

Description

LAMINATED BODY, METHOD FOR MANUFACTURING SAME, AND IMAGE DISPLAY DEVICE

The present invention relates to a laminate in which an inorganic thin film is provided on a film substrate, a manufacturing method thereof, and an image display device.

An antireflection film is sometimes provided on the surface of image display devices such as liquid crystal displays and organic EL displays for the purpose of improving the visibility of displayed images. An antireflection film has an antireflection layer composed of a plurality of thin films having different refractive indices on a film substrate. An antireflection film using an inorganic thin film such as an inorganic oxide as the thin film forming the antireflection layer can easily adjust the refractive index and film thickness, and therefore can achieve high antireflection properties.

Since the antireflection film is placed on the outermost surface of the image display device, a hard coat layer may be provided on the antireflection layer formation surface of the film substrate for the purpose of preventing damage due to contact from the outside. In general, the adhesion between the hard coat layer and the inorganic thin film, which are made of organic substances, is low, and delamination may occur between the hard coat layer and the inorganic thin film. is proposed.

The provision of a primer layer tends to improve the adhesion of inorganic thin films such as an antireflection layer, but in an environment exposed to ultraviolet rays such as outdoors, even if a primer layer is provided, the inorganic thin film may deteriorate due to light deterioration. Adhesion may decrease. In Patent Document 1, a primer layer made of silicon oxide (SiO _x ; 0<x<2) in an oxygen-deficient state (non-stoichiometric composition) is formed on a hard coat layer, and an antireflection layer is formed thereon. By doing so, the antireflection layer has high adhesion even after high-intensity light irradiation (weather resistance test).

WO2016/190415

A primer layer made of silicon oxide with a non-stoichiometric composition is deposited by reactive sputtering using a silicon target. The present inventors have found that the antireflection film provided with a silicon oxide thin film as a primer layer between the hard coat layer and the antireflection layer has unstable characteristics such as adhesion and transparency of the antireflection layer. It turns out there is. In view of such problems, an object of the present invention is to provide a laminate having excellent quality stability such as adhesion of an inorganic thin film.

The present invention relates to a laminate and its manufacturing method. The laminate includes a hard coat film having a hard coat layer on one main surface of a film substrate, a primer layer provided in contact with the hard coat layer, and an inorganic thin film provided in contact with the primer layer. Prepare. In one embodiment, the inorganic thin film formed on the primer layer is an antireflection layer comprising a laminate of a plurality of thin films having different refractive indices. Each thin film constituting the antireflection layer may be an inorganic oxide thin film.

The primer layer is a metal oxide thin film and contains oxides of specific metal elements. The metal element of the metal oxide preferably has a metal-oxygen bond dissociation energy of 450 to 780 kJ/mol at a temperature of 298K. Examples of metal elements include Sc, Y, Ti, Zr, V, Nb, Cr, Mo, W, Tc, Re, Ru, Os, Al, and Sn. Among them, Ti and Sn are particularly preferred. It is preferable that the total amount of these metal elements is 50 atomic % or more based on the total amount of metal elements in the metal oxide.

The primer layer is deposited, for example, by sputtering using an oxide target. The thickness of the primer layer is preferably about 0.5 to 30 nm.

The formation of the inorganic thin film on the primer layer may be performed by reactive sputtering.

The hard coat layer may contain a binder resin and fine particles. In one embodiment, the hard coat layer contains a binder resin and nanoparticles with a particle size of 10 to 100 nm, and the content of the nanoparticles is 20 to 100 parts by weight based on 100 parts by weight of the binder resin.

By providing a primer layer containing an oxide of a specific metal element between the hard coat layer and the inorganic thin film such as the antireflection layer, a laminate with high adhesion of the inorganic thin film even after the weather resistance test can be obtained.

FIG. 3 is a cross-sectional view showing a lamination configuration of antireflection films.

The laminate of the present invention comprises a primer layer on the hard coat layer of the hard coat film, and an inorganic thin film thereon. Such laminates include films for image display devices such as antireflection films and transparent electrode films, solar radiation control films, heat shielding/insulating films, light control films, electromagnetic wave shielding films, and the like, which are provided on window glasses and show windows. film, gas barrier film, and the like.

FIG. 1 is a cross-sectional view showing a laminated configuration example of an antireflection film as an embodiment of the laminate. The antireflection film 100 includes a hard coat film 1 having a hard coat layer 11 provided on one main surface of a film substrate 10, a primer layer 3 in contact with the hard coat layer 11, and an antireflection layer 5 in contact with the primer layer. Prepare. The antireflection layer 5 is a laminate of two or more inorganic thin films having different refractive indices. In the antireflection film 100 shown in FIG. 1, the antireflection layer 5 has a configuration in which high

refractive index layers

51 and 53 and low

refractive index layers

52 and 54 are alternately laminated.

[Hard coat film]
<Film substrate>
As the film substrate 10 of the hard coat film 1, for example, a transparent film is used. The visible light transmittance of the transparent film is preferably 80% or higher, more preferably 90% or higher. As the resin material that constitutes the transparent film, for example, a resin material that is excellent in transparency, mechanical strength, and thermal stability is preferable. Specific examples of resin materials include cellulose resins such as triacetyl cellulose, polyester resins, polyethersulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth) Examples include acrylic resins, cyclic polyolefin resins (norbornene resins), polyarylate resins, polystyrene resins, polyvinyl alcohol resins, and mixtures thereof.

The film substrate 10 does not necessarily have to be transparent. A laminate of a plurality of films may also be used as the film substrate 10 . For example, as will be described later, a polarizing plate in which a protective film is provided on the surface of a polarizer may be used as the film substrate 10 .

Although the thickness of the film substrate 10 is not particularly limited, it is preferably about 5 to 300 μm, more preferably 10 to 250 μm, and even more preferably 20 to 200 μm from the viewpoint of strength, workability such as handleability, and thinness.

<Hard coat layer>
The hard coat film 1 is formed by providing the hard coat layer 11 on the main surface of the film substrate 10 . The hard coat layer is a cured resin layer, and is formed by applying a composition containing a curable resin onto the film substrate and curing the resin component. The hard coat layer may contain fine particles in addition to the cured resin.

(Curable resin)
As the curable resin (binder resin) of the hard coat layer 11, curable resins such as thermosetting resins, photo-curable resins, and electron beam curable resins are preferably used. Types of curable resins include polyester, acrylic, urethane, acrylic urethane, amide, silicone, silicate, epoxy, melamine, oxetane, and acrylic urethane. Among these resins, acrylic resins, acrylic urethane resins, and epoxy resins are preferable because they have high hardness and can be photocured, and acrylic urethane resins are particularly preferable.

The photocurable resin composition contains a polyfunctional compound having two or more photopolymerizable (preferably ultraviolet-polymerizable) functional groups. Polyfunctional compounds may be monomeric or oligomeric. As the photopolymerizable polyfunctional compound, a compound containing two or more (meth)acryloyl groups in one molecule is preferably used.

Specific examples of polyfunctional compounds having two or more (meth)acryloyl groups in one molecule include tricyclodecanedimethanol diacrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, and trimethylol. propane triacrylate, pentaerythritol tetra(meth)acrylate, dimethylolpropane tetraacrylate, dipentaerythritol hexa(meth)acrylate, 1,6-hexanediol (meth)acrylate, 1,9-nonanediol diacrylate, 1, 10-decanediol (meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, dipropylene glycol diacrylate, isocyanuric acid tri(meth)acrylate, ethoxylated glycerin triacrylate, ethoxylated pentaerythritol tetra Examples include acrylates and oligomers or prepolymers thereof. In addition, in this specification, "(meth)acryl" means acryl and/or methacryl.

A polyfunctional compound having two or more (meth)acryloyl groups in one molecule may have a hydroxyl group. The use of a polyfunctional compound containing a hydroxyl group tends to improve the adhesion between the film substrate and the hard coat layer. Compounds having a hydroxyl group and two or more (meth)acryloyl groups in one molecule include pentaerythritol tri(meth)acrylate and dipentaerythritol penta(meth)acrylate.

Acrylic urethane resins contain urethane (meth)acrylate monomers or oligomers as polyfunctional compounds. The number of (meth)acryloyl groups in the urethane (meth)acrylate is preferably 3 or more, more preferably 4-15, and even more preferably 6-12. The molecular weight of the urethane (meth)acrylate oligomer is, for example, 3000 or less, preferably 500-2500, more preferably 800-2000. Urethane (meth)acrylate is obtained, for example, by reacting hydroxy (meth)acrylate obtained from (meth)acrylic acid or (meth)acrylic acid ester and polyol with diisocyanate.

The content of the polyfunctional compound in the composition for forming a hard coat layer is preferably 50 parts by weight or more with respect to a total of 100 parts by weight of the resin components (monomers, oligomers and prepolymers that form a binder resin upon curing). 60 parts by weight or more is more preferable, and 70 parts by weight or more is even more preferable. When the content of the polyfunctional monomer is within the above range, the hardness of the hard coat layer tends to be increased.

(fine particles)
By including fine particles in the hard coat layer 11, it is possible to adjust the surface shape, impart optical properties such as antiglare properties, and improve the adhesion of the antireflection layer.

Fine particles include inorganic oxide fine particles such as silica, alumina, titania, zirconia, calcium oxide, tin oxide, indium oxide, cadmium oxide, and antimony oxide, glass fine particles, polymethyl methacrylate, polystyrene, polyurethane, and acrylic-styrene copolymer. , benzoguanamine, melamine, polycarbonate, and other crosslinked or uncrosslinked organic microparticles can be used without particular limitation.

The average particle size (average primary particle size) of fine particles is preferably about 10 nm to 10 μm. Fine particles have a particle diameter of about 0.5 μm to 10 μm, submicrons or μm order (hereinafter sometimes referred to as “microparticles”), and have a particle diameter of about 10 nm to 100 nm. They can be roughly classified into microparticles (hereinafter sometimes referred to as “nanoparticles”) and microparticles having a particle size intermediate between microparticles and nanoparticles.

The inclusion of nanoparticles in the hard coat layer 11 tends to form fine irregularities on the surface and improve the adhesion between the hard coat layer 11 and the primer layer 3 and the antireflection layer 5 . As nanoparticles, inorganic fine particles are preferable, and inorganic oxide fine particles are particularly preferable. Among these, silica particles are preferable because they have a low refractive index and can reduce the difference in refractive index from the binder resin.

From the viewpoint of forming an uneven shape with excellent adhesion to the inorganic thin film on the surface of the hard coat layer 11, the average primary particle diameter of the nanoparticles is preferably 20 to 80 nm, more preferably 25 to 70 nm, and more preferably 30 to 60 nm. More preferred. From the viewpoint of suppressing coloring of reflected light on the surface of the hard coat layer, the average primary particle size of the nanoparticles is preferably 55 nm or less, more preferably 50 nm or less, and even more preferably 45 nm or less. The average primary particle size is the weight average particle size measured by the Coulter count method.

The amount of nanoparticles in the hard coat layer 11 may be about 1 to 150 parts by weight with respect to 100 parts by weight of the binder resin. From the viewpoint of forming a surface shape with excellent adhesion to the inorganic thin film on the surface of the hard coat layer 11, the content of the nanoparticles in the hard coat layer 11 is 20 to 100 parts by weight with respect to 100 parts by weight of the binder resin. parts, more preferably 25 to 90 parts by weight, even more preferably 30 to 80 parts by weight.

By including microparticles in the hard coat layer 11, projections with a diameter of submicron or μm order are formed on the surface of the hard coat layer 11 and the surface of the thin film formed thereon, thereby imparting antiglare properties. . The microparticles preferably have a small refractive index difference from the binder resin of the hard coat layer, and are preferably low refractive index inorganic oxide particles such as silica or polymer fine particles.

From the viewpoint of forming a surface shape suitable for imparting antiglare properties, the average primary particle size of the microparticles is preferably 1 to 8 μm, more preferably 2 to 5 μm. When the particle size is small, the antiglare property tends to be insufficient, and when the particle size is large, the definition of the image tends to decrease. The content of the microparticles in the hard coat layer 11 is not particularly limited, but is preferably 1 to 15 parts by weight, more preferably 2 to 10 parts by weight, and even more preferably 3 to 8 parts by weight with respect to 100 parts by weight of the binder resin.

The hard coat layer 11 may contain either one of nanoparticles and microparticles, or may contain both. It may also contain fine particles having a particle size intermediate between nanoparticles and microparticles.

(Formation of hard coat layer)
The composition for forming a hard coat layer contains the binder resin component described above and, if necessary, a solvent capable of dissolving the binder resin component. As described above, the composition for forming a hard coat layer may contain fine particles. When the binder resin component is a photocurable resin, the composition preferably contains a photopolymerization initiator. In addition to the above, the composition for forming a hard coat layer contains a leveling agent, a thixotropic agent, an antistatic agent, an antiblocking agent, a dispersant, a dispersion stabilizer, an antioxidant, an ultraviolet absorber, an antifoaming agent, and a thickener. , surfactants, and lubricants.

A hard coat layer is formed by applying the composition for forming a hard coat layer onto a film substrate, and optionally removing the solvent and curing the resin. The hard coat layer-forming composition may be applied by any appropriate method such as bar coating, roll coating, gravure coating, rod coating, slot orifice coating, curtain coating, fountain coating, and comma coating. method can be adopted. The heating temperature after application may be set to an appropriate temperature depending on the composition of the composition for forming a hard coat layer, and is, for example, about 50°C to 150°C. When the binder resin component is a photocurable resin, photocuring is performed by irradiating active energy rays such as ultraviolet rays. The integrated light quantity of the irradiation light is preferably about 100 to 500 mJ/cm ² .

Although the thickness of the hard coat layer 11 is not particularly limited, it is preferably about 1 to 10 μm, more preferably 2 to 9 μm, and even more preferably 3 to 8 μm from the viewpoint of achieving high hardness and appropriately controlling the surface shape.

Before forming the primer layer 3 and the antireflection layer 5 on the hard coat layer 11, for the purpose of further improving the adhesion between the hard coat layer 11 and the primer layer 3 and the antireflection layer 5, the hard coat layer 11 is formed. A surface treatment may be performed. Examples of surface treatment include surface modification treatments such as corona treatment, plasma treatment, flame treatment, ozone treatment, primer treatment, glow treatment, alkali treatment, acid treatment, and treatment with a coupling agent. A vacuum plasma treatment may be performed as the surface treatment. The surface roughness of the hard coat layer can also be adjusted by vacuum plasma treatment. For example, if vacuum plasma treatment is performed at high discharge power, the surface unevenness of the hard coat layer tends to increase and the adhesion to the inorganic thin film tends to improve.

<Primer layer>
A primer layer 3 is formed on the hard coat layer 11, and an antireflection layer 5 is formed thereon. By providing the primer layer 3 in contact with the hard coat layer 11 and providing the antireflection layer 5 in contact with the primer layer 3, the adhesion between the layers is excellent, and the reflection is reflected even when exposed to light such as ultraviolet rays for a long time. It is possible to obtain an antireflection film in which the antireflection layer is less likely to peel off.

The primer layer 3 is a metal oxide thin film. Note that the term “metal” here is a concept that does not include semimetals such as silicon. The metal oxide of the primer layer contains, as a metal element, a metal having a metal-oxygen bond dissociation energy D ⁰ ₂₉₈ at a temperature of 298K of 450 to 780 kJ/mol.

The bond dissociation energy D ⁰ (MO) between the metal element M and oxygen O is the amount of change in standard enthalpy in the bond dissociation of MO → M+O, and the thermochemical equation:
D ⁰ (M−O)=Δ _f H ⁰ (M)+Δ _f H ⁰ (O)−Δ _f H ⁰ (MO)
is derived from Δ _f H ⁰ is the enthalpy of formation. In the present specification, the value described in Luo, Y. R., Comprehensive Handbook of Chemical Bond Energies, CRC Press, 2007 is adopted as the bond dissociation energy D ⁰ ₂₉₈ (MO) between metal and oxygen at 298 ° C. do.

Metals having a D ⁰ ₂₉₈ (MO) of 450 to 780 kJ/mol include Cr (461±8.7), Al (501.9±10.6), Mo (502), Sn (528), Ru(528±42), Tc(548), Os(575), Re(627±84), V(637), Ti(666.5±5.6), Sc(671.4±1.0) , Y (714.1±10.2), W (720±71), Nb (726.5±10.6), Zr (766.1±10.6), and the like. The numbers in brackets are D ⁰ ₂₉₈ (MO)/kJmol ⁻¹ .

The larger the D ⁰ ₂₉₈ (M−O) of the metal element M constituting the primer layer, the more difficult it is for the antireflection layer to peel off even when exposed to light such as ultraviolet rays for a long time, and the antireflection film has better weather resistance. tend to be better. D ⁰ ₂₉₈ (MO) of the metal element M constituting the primer layer is preferably 480 kJ/mol or more, more preferably 500 kJ/mol or more, and may be 520 kJ/mol or more.

One of the presumed reasons why the weather resistance is improved by having a large D ⁰ ₂₉₈ (MO) is that the cleavage of the metal-oxygen bond by ultraviolet rays is difficult to occur, and the primer layer has excellent photostability. be done. 450 kJ/mol corresponds to photon energy at a wavelength of 267 nm. Therefore, if the material of the primer layer is a metal oxide having D ⁰ ₂₉₈ (M−O) of 450 kJ/mol or more, UVA (wavelength 320 to 400 nm) or UVB (wavelength 280 to 320 nm) can be applied. Also, the metal-oxygen bond is hardly cleaved, and the primer layer is not easily degraded by light, so it is considered to be excellent in weather resistance.

In principle, the larger ^{the D 0} ²⁹⁸ ₍ M−O), the better the weather resistance _. , the adhesion of the antireflection layer may be insufficient. For example, the D ⁰ ₂₉₈ (M−O) of silicon (Si), a semimetal, is about 800 kJ/mol, and a SiOx (x<2) primer layer lacking oxygen with respect to stoichiometry reflects Adhesion to the antireflection layer is excellent, but when a stoichiometric SiO ₂ primer layer is formed, adhesion to the antireflection layer tends to decrease after the weather resistance test.

Therefore, as described above, D ⁰ ₂₉₈ (MO) of the metal element M constituting the primer layer is preferably 780 kJ/mol or less. It is not clear why the adhesion decreases when D ⁰ ₂₉₈ (M−O) is too large, but one possibility is that dangling The presence of bonds improves the adhesion with other layers, whereas in the stoichiometric composition, the metal element M has a high affinity for oxygen and high stability, so It is conceivable that the contribution to the improvement of affinity is small.

Examples of the metal element M having a D ⁰ ₂₉₈ (MO) of 450 to 780 kJ/mol are as described above. Sc, Y, Ti, Zr, V, Nb, Cr, Mo, W, Tc, Re, Ru, Os, Al, and Sn are preferred from the viewpoint of properties. In particular, in applications requiring transparency such as antireflection films, Ti and Sn are preferred because they are excellent in oxide transparency and chemical stability.

The metal oxide constituting the primer layer may be a composite oxide, and as a dopant element, metal elements other than the above, and semi-metals such as B, C, Ge, P, As, Sb, Be, Se, Te, Po, At, etc. It may contain a metal element. From the viewpoint of maintaining high adhesion even after light irradiation, the ratio of the above metal to the total amount (100 atomic %) of the metal elements of the metal oxide constituting the primer layer 3 is preferably 50 atomic % or more, more preferably 60 atomic %. The above is more preferable, 70 atomic % or more is more preferable, and 80 atomic % or more, 90 atomic % or more, 95 atomic % or more, or 99 atomic % or more may be used.

Specifically, in the primer layer 3, the ratio of the metal having D ⁰ ₂₉₈ (M−O) of 450 kJ/mol or more with respect to the total amount of metal elements in the metal oxide is preferably within the above range, and D ⁰ ₂₉₈ (M It is more preferable that the ratio of the metal having —O) of 500 kJ/mol or more is within the above range. In addition, the primer layer 3 is the total content of Sc, Y, Ti, Zr, V, Nb, Cr, Mo, W, Tc, Re, Ru, Os, Al, and Sn with respect to the total amount of metal elements in the metal oxide. is preferably within the above range, and more preferably, the proportion of Ti or Sn is within the above range. That is, the primer layer is particularly preferably composed mainly of titanium oxide (TiO ₂ ) or tin oxide (SnO ₂ ).

As described above, the primer layer 3 containing a specific metal oxide is formed on the hard coat layer 11, and the antireflection layer 5 is formed thereon. However, peeling of the antireflection layer is unlikely to occur, and an antireflection film having excellent weather resistance can be obtained. In particular, when the hard coat layer 11 contains nanoparticles, the primer layer 3 tends to significantly improve the adhesion of the antireflection layer 5 .

The thickness of the primer layer 3 is, for example, about 0.5 to 30 nm, preferably 1 to 25 nm, and may be 2 nm or more or 3 nm or more. When the film thickness of the primer layer is within the above range, there is a tendency that the adhesion to the hard coat layer 11 is further enhanced. From the viewpoint of transparency, it is preferable that the thickness of the primer layer 3 is small within a range in which the adhesion to the hard coat layer 11 and the antireflection layer 5 can be ensured. The thickness of the primer layer 3 may be 20 nm or less, 15 nm or less, 10 nm or less, or 8 nm or less.

<Antireflection layer>
The antireflection layer 5 is a laminate of a plurality of thin films having different refractive indices. In general, the antireflection layer has an optical thickness (product of refractive index and thickness) of the thin film so that the reversed phases of incident light and reflected light cancel each other out. A multi-layer stack of thin films having different refractive indices can reduce the reflectance in a wide wavelength range of visible light. The thin film constituting the antireflection layer 5 is preferably an inorganic material, preferably a ceramic material made of metal or semimetal oxide, nitride, fluoride, etc. Among them, metal or semimetal oxide (inorganic oxide). is preferred.

The antireflection layer 5 is preferably an alternate laminate of high refractive index layers and low refractive index layers. In order to reduce reflection at the air interface, the thin film 54 provided as the outermost layer (layer farthest from the hard coat film 1) of the antireflection layer 5 is preferably a low refractive index layer.

The high refractive index layers 51 and 53 have, for example, a refractive index of 1.9 or more, preferably 2.0 or more. Examples of high refractive index materials include titanium oxide, niobium oxide, zirconium oxide, tantalum oxide, zinc oxide, indium oxide, indium tin oxide (ITO), and antimony-doped tin oxide (ATO). Among them, titanium oxide or niobium oxide is preferable. The low refractive index layers 52 and 54 have, for example, a refractive index of 1.6 or less, preferably 1.5 or less. Examples of low refractive index materials include silicon oxide, titanium nitride, magnesium fluoride, barium fluoride, calcium fluoride, hafnium fluoride, and lanthanum fluoride. Among them, silicon oxide is preferred. In particular, it is preferable to alternately stack niobium oxide (Nb ₂ O ₅ )

thin films

51 and 53 as high refractive index layers and silicon oxide (SiO ₂ )

thin films

52 and 54 as low refractive index layers. A medium refractive index layer having a refractive index of about 1.6 to 1.9 may be provided in addition to the low refractive index layer and the high refractive index layer.

The film thicknesses of the high refractive index layer and the low refractive index layer are each about 5 to 200 nm, preferably about 15 to 150 μm. The film thickness of each layer may be designed so that the reflectance of visible light is reduced according to the refractive index, lamination structure, and the like. For example, as a laminated structure of a high refractive index layer and a low refractive index layer, from the hard coat film 1 side, a high refractive index layer 51 having an optical thickness of about 25 nm to 55 nm and a low refractive index layer having an optical thickness of about 35 nm to 55 nm 52, a high refractive index layer 53 with an optical thickness of about 80 nm to 240 nm, and a low refractive index layer 54 with an optical thickness of about 120 nm to 150 nm. The antireflection layer is not limited to a 4-layer structure, and may have a 2-layer structure, a 3-layer structure, a 5-layer structure, or a lamination structure of 6 or more layers.

<Formation of primer layer and antireflection layer>
A method for forming the thin films constituting the primer layer 3 and the antireflection layer 5 is not particularly limited, and may be either a wet coating method or a dry coating method. A dry coating method such as vacuum deposition, CVD, sputtering, or electron beam deposition is preferred because it can form a thin film with a uniform thickness. Among them, the sputtering method is preferable because it is excellent in the uniformity of the film thickness and can easily form a dense film.

In the sputtering method, a thin film can be formed continuously while transporting the film substrate in one direction (longitudinal direction) by a roll-to-roll method. Therefore, the productivity of the antireflection film including the primer layer 3 and the antireflection layer 5 composed of a plurality of thin films on the hard coat film 1 can be improved.

In the sputtering method, film formation is performed while introducing an inert gas such as argon and, if necessary, a reactive gas such as oxygen into the chamber. The deposition of the oxide layer by the sputtering method can be carried out by either a method using an oxide target or reactive sputtering using a (semi)metal target.

Since the inorganic oxide can be deposited at a high rate, the thin film forming the antireflection layer 5 is preferably deposited by reactive sputtering using a metal or semimetal target. DC or MF-AC is preferable as a sputtering power source used for reactive sputtering.

In reactive sputtering, film formation is performed while introducing an inert gas such as argon and a reactive gas such as oxygen into the chamber. In reactive sputtering, it is preferable to adjust the amount of oxygen so that the transition region is intermediate between the metal region and the oxide region. When the film is formed in the metal region, the amount of oxygen in the obtained film is smaller than the stoichiometric composition, resulting in an oxygen-deficient state, and the antireflection layer tends to have a metallic luster and decrease in transparency. Also, in an oxide region with a large amount of oxygen, the film formation rate tends to be extremely low.

An oxide film can be deposited at a high rate by adjusting the amount of oxygen so that sputtering deposition is in the transition region. As a method for controlling the amount of oxygen introduced so that the deposition mode is in the transition region, there is a plasma emission monitoring method (PEM method) in which the plasma emission intensity of the discharge is detected and the amount of gas introduced into the deposition chamber is controlled. mentioned. In PEM, control is performed by detecting the plasma emission intensity and feeding it back to the amount of oxygen introduced. For example, by setting the emission intensity control value (set point) within a predetermined range and performing PEM control to adjust the oxygen introduction amount, film formation in the transition region can be maintained. An impedance method may be used to control the amount of introduced oxygen so that the plasma impedance is constant, that is, the discharge voltage is constant.

It is preferable to use an oxide target for forming the primer layer 3 . Reactive sputtering using a metal target has the advantage of a high film formation rate, but on the other hand, the film quality may change due to a slight change in the introduction amount of a reactive gas such as oxygen. On the other hand, if an oxide target is used, the film quality of the primer layer is stabilized because the film quality does not change much even when the film formation conditions such as the amount of oxygen introduced are changed. If a conductive oxide target such as titanium oxide or tin oxide is used, it is possible to form a film at a high rate by DC sputtering. An oxide target with a small amount of dopant added may be used to enhance conductivity.

The substrate temperature when the primer layer is formed by sputtering is about -30 to 150°C, and is not particularly limited as long as the hard coat film as the substrate material has durability. The pressure and power density for forming the primer layer by sputtering can be appropriately set according to the type of target and the film thickness of the primer layer.

When forming the primer layer 3 by sputtering using an oxide target, it is preferable to introduce an oxidizing gas such as oxygen in addition to an inert gas such as argon. By introducing oxygen, oxygen released from the target during sputtering is supplemented, so that an oxide thin film having a stoichiometric composition tends to be easily formed, and transparency and chemical stability tend to be improved. Further, the adhesion of the antireflection layer tends to improve as the amount of oxygen introduced during sputtering film formation increases. The amount of oxygen introduced during sputtering film formation is, for example, about 0.1 to 100 parts by volume, preferably 0.3 parts by volume or more, more preferably 0.5 parts by volume or more, with respect to 100 parts by volume of the inert gas. . From the viewpoint of improving the adhesion of the antireflection layer, the amount of oxygen introduced during sputtering film formation is preferably 1 part by volume or more, more preferably 5 parts by volume or more, and 10 parts by volume or more with respect to 100 parts by volume of the inert gas. is more preferable, and may be 15 parts by volume or more or 20 parts by volume or more. The amount of oxygen introduced during sputtering deposition is 80 parts by volume or less, 70 parts by volume or less, 60 parts by volume or less, 50 parts by volume or less, 40 parts by volume or less, or 30 parts by volume or less with respect to 100 parts by volume of the inert gas. There may be.

In reactive sputtering using a metal target, if the amount of oxygen introduced is small, the oxide may have a non-stoichiometric composition and the transparency of the primer layer may decrease. Oxygen vacancies are slight even if they are not introduced at all. When forming a transparent electrode, if the amount of oxygen introduced is excessively large, the conductivity tends to decrease. However, since the primer layer does not require conductivity, even if the amount of oxygen introduced is large, no particular problem occurs. . Rather, as the amount of oxygen introduced increases, the adhesion of the antireflection layer tends to improve. It is preferred to deposit a layer.

An antireflection film in which a silicon oxide layer is provided as a primer layer between a hard coat layer and an antireflection layer undergoes large fluctuations in film quality of the primer layer, and is likely to cause deterioration in adhesion and transparency. One of the factors that cause the film quality of the silicon oxide primer layer to fluctuate is that it is not easy to precisely control the composition (value of x) of SiO _x , which is an oxide of Si, which is a metalloid.

SiO _x is deposited by reactive sputtering using a Si target, but the composition changes due to slight differences in deposition conditions. If the amount of oxygen is small, the transparency tends to decrease, and if the amount of oxygen is large, _SiO2 (with a stoichiometric composition) having no oxygen vacancies is generated, and the adhesion of the antireflection layer is reduced. Tend. When an oxide target is used, the amount of oxygen can be appropriately controlled while monitoring the reaction by the above-mentioned PEM control or the like in the film formation of a complete oxide. It is not easy to control the amount of oxygen that is absorbed to be constant, and the characteristics tend to vary.

As described above, when forming a metal oxide primer layer using an oxide target, characteristic changes due to deviations in the amount of oxygen are unlikely to occur, and fine adjustment of the amount of oxygen is not required. Therefore, it is possible to provide an antireflection film with stable quality such as adhesion of the antireflection layer.

[Anti-fouling layer]
The antireflection film may comprise additional functional layers on the antireflection layer 5 . When a silicon oxide layer is arranged as the outermost low refractive index layer 54 of the antireflection layer 5, the wettability of the silicon oxide is high, and contaminants such as fingerprints and fingerprints are likely to adhere. Therefore, an antifouling layer (not shown) may be provided on the antireflection layer 5 for the purpose of preventing contamination from the external environment and facilitating removal of adhering contaminants.

When an antifouling layer is provided on the surface of the antireflection film, the difference in refractive index between the low refractive index layer 54 on the outermost surface of the antireflection layer 5 and the antifouling layer should be small from the viewpoint of reducing reflection at the interface. preferable. The refractive index of the antifouling layer is preferably 1.6 or less, more preferably 1.55 or less. As the material for the antifouling layer, fluorine group-containing silane compounds, fluorine group-containing organic compounds, and the like are preferable. The antifouling layer can be formed by a wet method such as a reverse coating method, a die coating method, or a gravure coating method, or a dry method such as a CVD method. The thickness of the antifouling layer is usually about 1 to 100 nm, preferably 2 to 50 nm, more preferably 3 to 30 nm.

[Usage form of antireflection film]
An antireflection film is used, for example, by placing it on the surface of an image display device such as a liquid crystal display or an organic EL display. For example, by arranging an antireflection film on the viewing side surface of a panel including an image display medium such as a liquid crystal cell or an organic EL cell, the reflection of external light can be reduced and the visibility of the image display device can be improved.

The antireflection film may be laminated with other films. For example, a polarizing plate with an antireflection layer can be formed by attaching a polarizer to the surface of the film substrate 10 on which the hard coat layer is not formed.

As a polarizer, dichroic substances such as iodine and dichroic dyes are added to hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and partially saponified ethylene-vinyl acetate copolymer films. and a polyene-based oriented film such as a dehydrated product of polyvinyl alcohol or a dehydrochlorinated product of polyvinyl chloride. Among them, since it has a high degree of polarization, a polyvinyl alcohol-based film such as polyvinyl alcohol or partially formalized polyvinyl alcohol is oriented in a predetermined direction by adsorbing a dichroic substance such as iodine or a dichroic dye. Alcohol (PVA) based polarizers are preferred.

A transparent protective film may be provided on the surface of the polarizer for the purpose of protecting the polarizer. The transparent protective film may be attached only to one surface of the polarizer, or may be attached to both surfaces. In general, a transparent protective film is provided on the surface of the polarizer opposite to the surface provided with the antireflection film. On the side of the polarizer on which the antireflection film is attached, the antireflection film also functions as a transparent protective film, so it is not necessary to provide a transparent protective film, but a transparent protective film may be provided between the polarizer and the antireflection film. may have been

As the material for the transparent protective film, the same materials as those described above as the material for the transparent film substrate are preferably used. An adhesive is preferably used for bonding the polarizer and the transparent film. Adhesives are based on acrylic polymer, silicone polymer, polyester, polyurethane, polyamide, polyvinyl alcohol, polyvinyl ether, vinyl acetate/vinyl chloride copolymer, modified polyolefin, epoxy polymer, fluorine polymer, rubber polymer, etc. Polymers can be appropriately selected and used. A polyvinyl alcohol-based adhesive is preferably used for bonding the PVA-based polarizer.

[Laminates other than antireflection films]
As described above, an embodiment of an antireflection film comprising an antireflection layer as an inorganic thin film on a hard coat layer of a film base via a primer layer has been described, but the primer layer comprises an inorganic thin film other than the antireflection layer. Also in the laminate, it can contribute to the improvement of adhesion and weather resistance.

　Inorganic thin film materials include metals and metal compounds (metal or metalloid oxides, nitrides, carbides, sulfides, fluorides, etc.). The inorganic thin film may be conductive, insulating, or semiconducting. The film thickness of the inorganic thin film (the total film thickness when a plurality of thin films are included) is, for example, about 1 nm to 1 μm, and may be appropriately adjusted according to the type of thin film, the function of the laminate, and the like.

The present invention will be described in more detail below by giving specific examples of an antireflection film having a primer layer provided between a hard coat layer and an antireflection layer, but the present invention is not limited to the following specific examples. do not have.

[Preparation of hard coat film]
In an ultraviolet curable acrylic resin composition (manufactured by DIC, product name “GRANDIC PC-1070”, refractive index at wavelength 405 nm: 1.55), the amount of silica particles with respect to 100 parts by weight of the resin component is 25 parts by weight. To, organosilica sol (“MEK-ST-L” manufactured by Nissan Chemical Industries, silica particles (inorganic filler) average primary particle size: 50 nm, silica particle particle size distribution: 30 nm to 130 nm, solid content 30% by weight) is added. and mixed to prepare a composition for forming a hard coat layer.

The above composition was applied to one side of a 40 μm-thick triacetyl cellulose film so that the thickness after drying was 6 μm, and dried at 80° C. for 3 minutes. After that, using a high-pressure mercury lamp, the coating layer was cured by irradiating ultraviolet light with an accumulated light amount of 200 mJ/cm ² to form a hard coat layer.

[Antireflection film 1]
<Surface treatment>
While transporting the hard coat film in a vacuum atmosphere of 0.5 Pa, the surface of the hard coat layer was subjected to argon plasma treatment at a discharge power of 1.0 kW.

<Formation of primer layer and antireflection layer>
The hard coat film after the plasma treatment was introduced into a roll-to-roll type sputtering film forming apparatus, and the pressure in the tank was reduced to 1×10 ⁻⁴ Pa. Then, while the film was running, the substrate temperature was −8° C., and a thickness of 4 nm was formed. A SiO ₂ primer layer, a 16 nm Nb ₂ O ₅ layer, a 19 nm SiO ₂ layer, a 102 nm Nb ₂ O ₅ layer and a 71 nm SiO ₂ layer were formed in order on the hard coat layer forming surface.

For the formation of the _SiO2 primer layer, a Si target was used, and DC sputtering was performed under the conditions of a pressure of 0.2 Pa and a power density of 0.5 W/ ^cm2 while introducing 20 parts by volume of oxygen to 100 parts by volume of argon. membrane was performed.

A Si target was used to form the SiO ₂ layer (low refractive index layer), and a Nb target was used to form the Nb ₂ O ₅ layer (high refractive index layer). rice field. In the deposition of the SiO ₂ layer and the Nb ₂ O ₅ layer, the amount of introduced oxygen was adjusted by plasma emission monitoring (PEM) control so that the deposition mode maintained the transition region.

[Antireflection film 2]
In the same manner as in the preparation of antireflection film 1, a hard coat film was prepared and the surface was treated with argon plasma. The hard coat film after the plasma treatment was introduced into a roll-to-roll type sputtering film forming apparatus, and the pressure in the tank was reduced to 1×10 ⁻⁴ Pa. Then, while the film was running, the substrate temperature was −8° C., and a thickness of 6 nm was formed. A TiO ₂ primer layer, a 16 nm Nb ₂ O ₅ layer, a 19 nm SiO ₂ layer, a 102 nm Nb ₂ O ₅ layer and a 71 nm SiO ₂ layer were sequentially deposited on the hard coat layer forming surface.

The TiO ₂ primer layer was formed by DC sputtering under the conditions of a pressure of 0.2 Pa and a power density of 0.5 W/cm ² while introducing 6 parts by volume of oxygen to 100 parts by volume of argon using a titanium oxide target. A film was formed. The SiO ₂ layer and the Nb ₂ O ₅ layer were deposited under the same conditions as the antireflection film 1.

[Antireflection films 3 to 7]
The oxide target used for forming the primer layer was changed to tin oxide (SnO ₂ ), molybdenum oxide (WO ₃ ), chromium oxide (CrO ₃ ), nickel oxide (NiO), and zinc oxide (ZnO), and the film was formed. The amount of oxygen introduced and the film thickness were changed as shown in Table 1. An antireflection film having an antireflection layer on a hard coat layer via a primer layer was produced in the same manner as in the production of antireflection film 2 except for these changes.

[Evaluation of Adhesion of Antireflection Layer]
<Accelerated weathering test>
The surface of the antireflection film on the hard coat film side (surface without antireflection layer) is pasted on a glass plate via a transparent acrylic adhesive, and is heated to 40 using an "UV fade meter U48" manufactured by Suga Test Instruments. An accelerated weather resistance test was performed for 500 hours under the conditions of °C, humidity of 20%, and radiation intensity (accumulated illumination of 300 to 700 nm) of 500 ± 50 W/ ^m2 .

<Evaluation of Adhesion>
For each of the samples not subjected to the accelerated weathering test and the samples after the accelerated weathering test, cuts were made at intervals of 1 mm on the surface of the antireflection layer to form a grid of 100 squares. Next, 2 mL of isopropyl alcohol was continuously dropped so that the surface of the antireflection layer would not dry, and a polyester wiper ("Anticon Gold" manufactured by Sunplatec) fixed to a 20 mm square SUS jig was rubbed on a grid pattern. It was moved (load: 1.5 kg, 1000 reciprocations). The number of grid patterns in which the antireflection layer was peeled off in a region of 1/4 or more of the area of the mass was counted, and the adhesion was evaluated according to the following criteria.
A: The number of peeled grids is 10 or less B: The number of peeled grids is 11 to 50 C: The number of peeled grids is 51 or more

For each of the antireflection films 1 to 7, the metal type of the primer layer, the amount of oxygen introduced during the formation of the primer layer (volume ratio to argon) and the thickness of the primer layer, and the adhesion of the antireflection layer before and after the accelerated weathering test Table 1 shows the evaluation results.

All of the antireflection films 1 to 7 exhibited good adhesion of the antireflection layer before the accelerated weathering test. The anti-reflection film 1, in which the SiO ₂ primer layer was formed by reactive sputtering using a silicon target, exhibited a significant decrease in adhesion after the accelerated weathering test. In addition, in the sample (data not shown in Table 1) in which the SiOx (x<2) primer layer was formed by changing the amount of oxygen introduced during the formation of the primer layer to 3 parts by volume with respect to 100 parts by volume of argon, Even after the accelerated weathering test, the antireflection layer exhibited good adhesion, but a decrease in transmittance was observed.

The antireflection film 2 in which titanium oxide (D ⁰ ₂₉₈ of Ti—O = 666 kJ/mol) was deposited as a primer layer showed good adhesion of the antireflection layer even after the accelerated weathering test. Antireflection film 3 formed with tin oxide (Sn—O: D ⁰ ₂₉₈ =528 kJ/mol) as a primer layer and reflection formed with tungsten oxide (WO: D ⁰ ₂₉₈ =720 kJ/mol) as a primer layer The prevention film 4 was also the same.

Antireflection film 5 in which chromium oxide (Cr—O: D ⁰ ₂₉₈ =461 kJ/mol) was deposited as a primer layer had better adhesion of the antireflection layer after the accelerated weathering test than antireflection films 2 to 4. decreased. Antireflection film 5 with nickel oxide (Ni—O: D ⁰ ₂₉₈ =461 kJ/mol) as a primer layer, and zinc oxide (Zn—O: D ⁰ ₂₉₈ <250 kJ/mol) as a primer layer. The antireflection film 6 showed a marked decrease in adhesion after the accelerated weathering test.

From the above results, it can be concluded that by forming an oxide thin film of a metal element having a large bond dissociation energy with oxygen as a primer layer on the hard coat layer and then forming an inorganic thin film such as an antireflection layer thereon, weather resistance can be improved. It can be seen that a laminate with high adhesion of the inorganic thin film can be obtained even after the test.

REFERENCE SIGNS LIST 1 hard coat film 10 film substrate 11 hard coat layer 3 primer layer 5

antireflection layer

51, 53 high refractive index layers 52, 54 low refractive index layer 100 antireflection film

Claims

A laminate comprising: a hard coat film comprising a hard coat layer on one main surface of a film substrate; a primer layer provided on and in contact with said hard coat layer; and an inorganic thin film provided on and in contact with said primer layer being a body,
The primer layer is a metal oxide thin film,
The metal element of the metal oxide contains a metal having a metal-oxygen bond dissociation energy of 450 to 780 kJ / mol at a temperature of 298 K,
laminate.
A laminate comprising: a hard coat film comprising a hard coat layer on one main surface of a film substrate; a primer layer provided on and in contact with said hard coat layer; and an inorganic thin film provided on and in contact with said primer layer being a body,
The primer layer is a metal oxide thin film,
As metal elements of the metal oxide, one or more selected from the group consisting of Sc, Y, Ti, Zr, V, Nb, Cr, Mo, W, Tc, Re, Ru, Os, Al and Sn ,
laminate.
The laminate according to claim 1 or 2, wherein the primer layer has a thickness of 0.5 to 30 nm.
The laminate according to any one of claims 1 to 3, wherein the hard coat layer contains a binder resin and fine particles.
The hard coat layer contains a binder resin and nanoparticles with a particle size of 10 to 100 nm,
The laminate according to any one of claims 1 to 4, wherein the content of the nanoparticles is 20 to 100 parts by weight with respect to 100 parts by weight of the binder resin.
The laminate according to any one of claims 1 to 5, wherein the inorganic thin film is an antireflection layer comprising a laminate of a plurality of thin films having different refractive indices.
The laminate according to claim 6, wherein all of the plurality of thin films forming the antireflection layer are inorganic oxide thin films.
An image display device, wherein the layered product according to claim 6 or 7 is arranged on the viewing side surface of an image display medium.
A method for producing a laminate according to any one of claims 1 to 7,
A method for producing a laminate, comprising forming a primer layer on a hard coat layer by a sputtering method using an oxide target.
The method for manufacturing a laminate according to claim 9, wherein an inorganic thin film is formed on the primer layer by reactive sputtering.