WO2019064969A1

WO2019064969A1 - Anti-reflection film, method for producing same, and polarizing plate with anti-reflection layer

Info

Publication number: WO2019064969A1
Application number: PCT/JP2018/030156
Authority: WO
Inventors: 幸大宮本; 由佳山▲崎▼; 金谷　実; 智剛梨木
Original assignee: 日東電工株式会社
Priority date: 2017-09-28
Filing date: 2018-08-10
Publication date: 2019-04-04
Also published as: JP2019066515A; CN111183373B; JP2023057085A; CN111183373A; JP7304129B2; KR102653072B1; TW201919866A; KR20200037413A; KR20220149625A

Abstract

This anti-reflection film (100) comprises an anti-reflection layer (5), which is composed of a plurality of thin films having different refractive indexes, on one main surface of a transparent film substrate (1). The anti-reflection layer comprises a primer layer (50) that is in contact with the transparent film substrate. The primer layer has an argon content of 0.5% by atom or less. The primer layer (50) is, for example, a silicon oxide layer. It is preferable that the anti-reflection film has a water vapor permeability of 1 g/m2·24h or less. A polarizing plate (101) with an anti-reflection layer according to the present invention comprises the above-described anti-reflection film (100) on a polarizer (8).

Description

Antireflection film, method for producing the same, and polarizing plate with antireflection layer

The present invention relates to an antireflective film comprising an antireflective layer consisting of a plurality of thin films on a transparent film, and a method of manufacturing the same.

An antireflective film is used on the viewing side surface of an image display device such as a liquid crystal display or an organic EL display for the purpose of preventing deterioration in image quality due to reflection of external light or reflection of an image, and improvement of contrast. The antireflective film comprises an antireflective layer formed of a laminate of a plurality of thin films having different refractive indexes on a transparent film.

The polarizing plate with an anti-reflective layer is mentioned as one form of an anti-reflective film. An antireflective film is attached to the surface of the polarizing plate or an antireflective film is attached to the surface of the polarizer as a protective film to obtain a polarizing plate with an antireflective layer. An antireflective layer may be formed on the surface of the polarizing plate.

There are several known attempts to impart water vapor barrier properties to the antireflective layer. For example, in Patent Document 1, the water vapor barrier property is enhanced by forming an alternately laminated film of ITO and SiO ₂ by a sputtering method and forming a silicon oxide film thereon by a plasma CVD method. In patent document 2, low moisture permeation of an antireflection film is achieved by providing a silicon nitride film of high refractive index. Patent Document 3 describes that there is a high correlation between the density of the outermost layer of the antireflective layer (the layer farthest from the film substrate) and the moisture permeability.

JP 2000-338305 A Japanese Patent Application Publication No. 2003-139907 JP, 2009-109850, A

By providing the antireflective layer having a water vapor barrier property on the surface of the polarizing plate, the deterioration of the polarizer in a high humidity environment is suppressed, and the durability is improved. In recent years, displays have been required to have further high humidity durability, and an antireflective film (having a low moisture permeability) having a water vapor barrier property higher than that of the prior art has been required. In view of the above, the present invention aims to provide an antireflection film excellent in water vapor barrier properties.

The antireflective film of the present invention is provided with an antireflective layer composed of a plurality of thin films having different refractive indexes on one main surface of a transparent film substrate. The antireflective layer comprises a primer layer in contact with the transparent film substrate. It is preferable that high refractive index layers and low refractive index layers be alternately laminated on the primer layer. The moisture permeability of the antireflective film is preferably 1 g / m ² · 24 h or less.

The argon content of the primer layer is preferably 0.01 to 0.5 atomic% or less. The primer layer is preferably a silicon oxide layer. The primer layer is preferably formed by sputtering. The thin film on the primer layer constituting the antireflective layer is also preferably formed by sputtering.

Furthermore, the present invention relates to a polarizing plate with an antireflection layer provided with the above-mentioned antireflection film on one side of a polarizer.

The antireflective film of the present invention is excellent in bath barrier properties, and even when a display provided with a polarizing plate with an antireflective layer having low moisture permeability on the surface is exposed to a high humidity environment, the amount of water penetration into the polarizer is small. And deterioration of the polarizer can be suppressed.

It is sectional drawing which shows typically one form of an antireflection film. It is sectional drawing which shows typically one form of a polarizing plate with a reflection prevention layer.

[Structure of antireflective film]
FIG. 1: is sectional drawing which shows typically the structure of the anti-reflective film concerning one Embodiment. The antireflective film 100 includes the antireflective layer 5 in contact with the transparent film substrate 1. The antireflective layer is a laminate of thin films of two or more layers, and the antireflective layer 5 shown in FIG. 1 is provided with a primer layer 50 on the surface in contact with the transparent film substrate 1, and the high

refractive index layer

51, 53 and low

refractive index layers

52 and 54 are alternately stacked.

Moisture permeability of the antireflection layer 5 is preferably not more than 1g ^/ m 2 · 24h, more preferably not more than 0.7g ^/ m 2 · 24h. 0.5 g / m ² · 24 h or less is more preferable. By reducing the moisture permeability of the antireflective layer, it is possible to prevent the entry of water and to suppress the deterioration of the polarizer and the like due to the water. As will be described in detail later, when the amount of argon contained in the primer layer is small, the moisture permeability of the antireflective film tends to be small.

<Transparent film substrate>
The transparent film substrate 1 includes a flexible transparent film 10. It is preferable that the hard coat layer 11 be provided on the side of the transparent film 10 on which the antireflection layer 5 is formed.

(Transparent film)
The visible light transmittance of the transparent film 10 is preferably 80% or more, more preferably 90% or more. The thickness of the transparent film 10 is not particularly limited, but is preferably about 5 to 300 μm, more preferably 10 to 250 μm, and still more preferably 20 to 200 μm, from the viewpoints of strength and workability such as handleability and thin layer property.

As a resin material which comprises the transparent film 10, the thermoplastic resin which is excellent in transparency, mechanical strength, and heat stability is mentioned, for example. Specific examples of such thermoplastic resins include cellulose resins such as triacetyl cellulose, polyester resins, polyether sulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, polyimide resins, and polyolefin resins. And (meth) acrylic resins, cyclic polyolefin resins (norbornene resins), polyarylate resins, polystyrene resins, polyvinyl alcohol resins, and mixtures thereof.

(Hard coat layer)
By providing the hard coat layer 11 on the surface of the transparent film 10, mechanical properties such as hardness and elastic modulus of the antireflection film can be improved. The hard coat layer 11 preferably has high surface hardness and excellent scratch resistance. The hard coat layer 11 can be formed, for example, by applying a solution containing a curable resin on the transparent film 10.

Examples of the curable resin include thermosetting resin, ultraviolet curable resin, electron beam curable resin and the like. Examples of the curable resin include various resins such as polyester resins, acrylic resins, urethane resins, acrylic urethane resins, amide resins, silicone resins, silicate resins, epoxy resins, melamine resins, oxetane resins and acrylic urethane resins. One or two or more of these curable resins can be appropriately selected and used.

Among these, acrylic resins, acrylic urethane resins, and epoxy resins are preferable, and among them, acrylic urethane resins are preferable, because they are high in hardness, can be cured by ultraviolet light, and are excellent in productivity. The UV curable resin includes UV curable monomers, oligomers, polymers and the like. The UV curable resin preferably used is, for example, a resin having a UV polymerizable functional group, and a resin containing an acrylic monomer or oligomer having 2 or more, particularly 3 to 6 of the functional groups as a component.

The hard coat layer 11 may have an antiglare property in order to give the antireflective film the antiglare property and the antiglare property. Examples of the antiglare hard coat layer include those obtained by dispersing fine particles in the above-mentioned curable resin matrix. As fine particles to be dispersed in the resin matrix, various metal oxide fine particles such as silica, alumina, titania, zirconia, calcium oxide, tin oxide, indium oxide, cadmium oxide, antimony oxide etc., glass fine particles, polymethyl methacrylate, polystyrene, polyurethane Those having transparency, such as crosslinked or uncrosslinked organic fine particles and silicone fine particles comprising various transparent polymers such as acrylic-styrene copolymer, benzoguanamine, melamine and polycarbonate, can be used without particular limitation.

The hard coat layer 11 can be formed, for example, by applying a solution containing a curable resin on the transparent film 10. It is preferable that the ultraviolet polymerization initiator is mix | blended with the solution for forming a hard-coat layer. In order to form an antiglare hard coat layer containing fine particles, it is preferable to apply a solution containing the above fine particles in addition to the curable resin on a transparent film. The solution may contain additives such as a leveling agent, a thixotropic agent, an antistatic agent and the like.

The thickness of the hard coat layer 11 is not particularly limited, but is preferably 0.5 μm or more, and more preferably 1 μm or more in order to achieve high hardness. In consideration of the ease of formation by coating, the thickness of the hard coat layer is preferably 15 μm or less, more preferably 10 μm or less.

The arithmetic mean roughness Ra of the surface of the transparent film substrate 1 on the side on which the antireflection layer 5 is formed is preferably 1.0 nm or less. When the hard coat layer 11 is formed on the transparent film 10, the arithmetic mean roughness Ra of the hard coat layer 11 is the arithmetic mean roughness of the surface of the transparent film 10 on which the antireflection layer 5 is formed. Arithmetic mean roughness Ra is determined from an observation image of 1 μm square using an atomic force microscope (AFM).

As described above, when the hard coat layer 11 is formed by coating, the arithmetic mean roughness of the surface of the transparent film substrate 1 can be reduced. If the surface of the transparent film substrate 1 is smooth, defects such as pinholes of the antireflective layer 5 can be suppressed, so that an antireflective film with lower moisture permeability can be obtained.

(surface treatment)
The surface of the transparent film substrate 1 is treated with corona treatment, plasma treatment, flame treatment, ozone treatment, primer treatment, glow treatment, saponification treatment, coupling agent for the purpose of improving adhesion with the antireflective layer 5 and the like. Surface modification treatment such as treatment may be performed.

<Antireflection layer>
An antireflective film is formed by providing the antireflective layer 5 on the transparent film substrate 1. The antireflective layer 5 is provided with a primer layer 50 on the surface in contact with the transparent film substrate 1 and further includes a high refractive index layer and a low refractive index layer thereon. In general, in the antireflection layer, the optical film thickness (the product of the refractive index and the thickness) of the thin film is adjusted such that the inverted phases of the incident light and the reflected light cancel each other. By forming the antireflective layer as a multilayer laminate of a plurality of thin films having different refractive indices, the reflectance can be reduced in the wide wavelength range of visible light.

Examples of the material of the thin film constituting the antireflective layer 5 include metal oxides, nitrides, and fluorides. As a material of the primer layer 50, silicon oxide is preferable. The primer layer 50 has an argon content of 0.5 atomic% or less in the film. 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 and magnesium fluoride. 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 the high refractive index material include titanium oxide, niobium oxide, zirconium oxide, indium tin oxide (ITO), antimony-doped tin oxide (ATO) and the like. In addition to the low refractive index layer and the high refractive index layer, as a middle refractive index layer having a refractive index of about 1.6 to 1.9, for example, a thin film comprising titanium oxide or a mixture of the low refractive index material and the high refractive material May be provided.

The film forming method of the thin film forming the antireflective layer 5 is not particularly limited, and any of a wet coating method and a dry coating method may be used. A dry coating method such as vacuum deposition, CVD, sputtering, electron beam evaporation and the like is preferable because a thin film having a uniform film thickness can be formed. Among them, the sputtering method is preferable because it is easy to form a dense film having excellent uniformity of film thickness and high gas barrier properties. In particular, in order to obtain a low moisture permeation anti-reflection film, it is preferable to form silicon oxide as the primer layer 50 by sputtering.

In the sputtering method, since a plurality of thin films can be continuously formed while conveying a long film substrate in one direction (longitudinal direction) by a roll-to-roll method, productivity of the antireflective film can be improved. In order to improve the productivity of the antireflective film, it is preferable to form all the thin films constituting the antireflective layer 5 by sputtering. 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 oxide layer can be formed by sputtering either by using an oxide target or by reactive sputtering using a metal target. In order to deposit an insulating oxide such as silicon oxide using an oxide target, an RF discharge is required. In order to form a metal oxide film at a high rate, reactive DC sputtering using a metal target is preferable.

(Primer layer)
In the primer layer 50, the amount of argon in the film is 0.5 atomic% or less, preferably 0.4 atomic% or less. When the amount of argon in the sputtered film is 0.5 atomic% or less, the moisture permeability tends to be reduced, and the water vapor barrier property of the antireflection film tends to be improved. The reason why the antireflective layer becomes low moisture permeable by reducing the amount of argon in the film of the primer layer is not clear, but one factor is that if argon with a large atomic radius is present in the primer layer, it is formed on the primer layer and above It is considered to be related to the fact that a path of gas such as water vapor is easily formed in the thin film.

As described above, in sputtering film deposition, argon is used as a process gas, and high energy argon is caused to collide with the target to eject material from the target and sputter particles ejected from the target are deposited on the substrate. Film formation is performed. An inert gas such as argon does not generally participate in film formation, but since ionized argon has high reactivity, part of argon as a process gas is inevitably taken into the film during sputter film formation. .

Since argon, which is a rare gas, has a larger atomic diameter than silicon and oxygen, argon incorporated into the film inhibits formation of a Si-O bond network of silicon oxide, and causes an atomic level void to be formed. It can be When a void resulting from mixing of argon is formed in the primer layer 50 which is first deposited in contact with the film substrate 1, the high refractive index layers 51, 53 and the low refractive index layers 52, 54 are sputtered thereon When the film is formed, the voids tend to grow in a columnar direction in the thickness direction, which is considered to be a path of a gas such as water vapor and the moisture permeability is increased. On the other hand, it is considered that, by reducing the amount of argon taken into the primer layer 50, the formation of voids serving as water vapor paths is suppressed, and a low moisture permeation antireflective layer having excellent water vapor barrier properties is formed. .

The amount of argon contained in the primer layer 50 is preferably as small as possible, but a film obtained by sputtering film formation using argon as a process gas usually contains 0.01 atomic% or more of argon. The argon content in the primer layer may be 0.05 atomic% or more, or 0.1 atomic% or more. The amount of argon in the film is measured by the Rutherford backscattering (RBS) method, and the amount of argon in the silicon oxide film is a calculated value based on the sum of the contents of silicon, oxygen and argon being 100 atomic%.

As a method of suppressing the mixing of argon into the primer layer, it is preferable to increase the mean free path by reducing the process pressure at the time of film formation to promote the scattering of argon. The process pressure for forming the primer layer 50 is preferably about 0.05 to 2 Pa, more preferably about 0.07 to 1 Pa, still more preferably 0.1 to 0.5 Pa, and particularly preferably 0.1 to 0.3 Pa preferable. The amount of oxygen introduced into the film forming chamber at the time of film formation of the primer layer 50 is preferably about 0.1 to 10% of the amount of argon introduced in terms of volume ratio, more preferably about 0.5 to 5%, and 1 to 3% A degree is more preferred.

By introducing oxygen in addition to argon at the time of sputtering film formation to promote the formation of the Si—O bond network, mixing of argon into the film tends to be suppressed. On the other hand, in order to improve the adhesion between the film substrate 1 and the antireflective layer 5, the primer layer 50 preferably has an oxygen content less than the stoichiometric composition. The film thickness of the primer layer 50 may be set to such an extent that the transparency of the transparent film substrate 1 is not impaired, and is, for example, about 1 to 10 nm.

(Thin film on primer layer)
The type of thin film formed on the primer layer 50 is not particularly limited. From the viewpoint of reducing the reflectance over a wide wavelength range, it is preferable to alternately provide the high refractive index layer and the refractive index. In order to reduce reflection at the air interface, the thin film 54 provided as the outermost layer (the layer farthest from the film substrate 1) of the antireflective layer 5 is preferably a low refractive index layer. As materials for the low refractive index layer and the high refractive index layer, oxides are preferable as described above. Among them, it is preferable to alternately laminate 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.

In sputter deposition of the low refractive index layer and the high refractive index layer on the primer layer, it is preferable to control the oxygen introduction amount so that the deposition mode is in the transition region. For example, in a plasma emission monitoring method (PEM method) in which the plasma emission intensity of discharge is detected to control the gas introduction amount to the film forming chamber, feedback to the oxygen introduction amount is performed based on the plasma emission intensity. By controlling the amount of oxygen introduced by PEM, when forming a thin film by roll-to-roll method, the film forming rate can be kept constant, so the thin film thickness becomes uniform, and the reflection is excellent in the anti-reflection characteristic A protective film is obtained. The uniformity of the quality in the width direction can also be improved by providing a plurality of plasma emission measurement points in the width direction and controlling the oxygen introduction amount by the PEM independently of each other.

<Additional Layer on Antireflection Layer>
The antireflective film may be provided with an additional functional layer on the surface of the antireflective layer 5. Since the antireflective film is disposed on the outermost surface of the display, it is susceptible to contamination from the external environment (fingerprint, hand, dust, etc.). In particular, the low refractive index layer 54 such as SiO ₂ provided on the outermost surface of the antireflective layer 5 has good wettability, and contaminants such as fingerprints and finger marks are easily attached. An antifouling layer (not shown) may be provided on the antireflective layer for the purpose of preventing contamination from the external environment or facilitating the removal of attached contaminants.

The antifouling layer preferably has a small difference in refractive index from the low refractive index layer 54 on the outermost surface of the antireflective layer 5. 1.6 or less is preferable and, as for the refractive index of an antifouling layer, 1.55 or less is more preferable. As a material of the antifouling layer, a fluorine group-containing silane compound, a fluorine group-containing organic compound, 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.

[Polarizer with antireflective layer]
The antireflective film is used, for example, disposed on the surface of a display. As shown in FIG. 2, a polarizing plate with an antireflection layer in which the antireflection film 100 is laminated with the polarizer 8 may be bonded to the surface of the display. In the antireflection film-attached polarizing plate 101 shown in FIG. 2, one surface of the polarizer 8 is bonded to the main surface of the transparent film substrate 1 opposite to the surface on which the antireflection film 5 is formed. A transparent film 9 is attached to the other surface of the polarizer 8. In this configuration, the film substrate 1 has both a function as a substrate for forming the antireflection layer 5 and a function as a protective film of the polarizer 8. In preparation of an anti-reflective film, the polarizer 8 and the film base material 1 may be bonded together, a polarizing plate may be produced, and the anti-reflective layer 5 may be formed on the film base 1 of a polarizing plate.

The polarizer 8 may be a hydrophilic polymer film such as a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, or an ethylene / vinyl acetate copolymer-based partially saponified film, or a dichroic dye such as iodine or a dichroic dye. Examples thereof include those obtained by adsorbing a substance and uniaxially stretched, and polyene-based oriented films such as dehydrated products of polyvinyl alcohol and dehydrochlorinated products of polyvinyl chloride.

Among them, polyvinyl alcohol or polyvinyl alcohol-based film such as partially formalized polyvinyl alcohol adsorbs a dichromatic substance such as iodine or a dichroic dye, and is oriented in a predetermined direction because it has a high degree of polarization. Alcohol (PVA) based polarizers are preferred. For example, a PVA-based polarizer can be obtained by subjecting a polyvinyl alcohol-based film to iodine dyeing and stretching. A thin polarizer having a thickness of 10 μm or less can also be used as the PVA-based polarizer. Examples of thin polarizers are described in, for example, JP-A-51-069644, JP-A-2000-338329, WO2010 / 100917, JP-A-4691205, JP-A-4751481, and the like. And thin polarizing films. Such a thin polarizer can be obtained, for example, by a manufacturing method including a step of stretching a PVA-based resin layer and a stretching resin base material in the state of a laminate, and a step of iodine staining.

As the transparent film 9, the same material as that described above as the material of the transparent film 10 is preferably used. The material of the transparent film 9 and the material of the transparent film 10 may be the same or different.

It is preferable to use an adhesive for bonding of the polarizer and the transparent film. Adhesives are based on acrylic polymers, silicone polymers, polyesters, polyurethanes, polyamides, polyvinyl alcohol, polyvinyl ether, vinyl acetate / vinyl chloride copolymers, modified polyolefins, epoxy polymers, fluorine polymers, rubber polymers, etc. What is to be a polymer can be appropriately selected and used. For adhesion of a PVA-based polarizer, a polyvinyl alcohol-based adhesive is preferably used.

The antireflection film and the polarizing plate with an antireflection layer of the present invention are used for a display such as a liquid crystal display device or an organic EL display device. In particular, when it is used as the outermost surface layer of the display, it contributes to the improvement of the visibility of the display by the reflection prevention. By providing the low moisture permeation anti-reflection film 100 provided with the predetermined primer layer 50 on the surface of the polarizer 8, it is possible to suppress the entry of moisture from the external environment into the polarizer 8. Therefore, even when the display is exposed to a high humidity environment, yellowing and fading due to deterioration of the polarizer are less likely to occur, and changes in display characteristics can be suppressed.

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the following examples.

[Preparation of film with hard coat layer]
A mixture of 100 parts by weight (solid content) of an ultraviolet curable acrylic resin (made by DIC, trade name "GRANDIC PC-1070", refractive index: 1.52) and 50 parts by weight of nanosilica particles as an inorganic filler, The composition for hard-coat layer formation was prepared. This composition was applied to one side of a 100 μm thick cellulose triacetate film (Fuji Film, trade name “Fujitack”) to a dry thickness of 5 μm and dried at 80 ° C. for 3 minutes. Thereafter, using a high pressure mercury lamp, ultraviolet rays of 200 mJ / cm ² of integrated light quantity were irradiated to cure the coating layer, thereby forming a hard coat layer.

Example 1
The triacetyl cellulose film on which the hard coat layer is formed is introduced into a roll-to-thol sputtering film forming apparatus, and the surface on which the antiglare hard coat layer is formed is bombarded (plasma treatment with Ar gas) while the film travels. After that, a 3.5 nm silicon oxide layer is formed as a primer layer, and 12 nm Nb ₂ O ₅ layer, 28 nm SiO ₂ layer, 100 nm Nb ₂ O ₅ layer and 85 nm SiO _{2 are formed} thereon. _Two layers were sequentially formed into a film to produce an antireflective film.

Bombardment was performed at a pressure of 1.5 Pa. The silicon oxide layer as the primer layer is formed by DC sputtering deposition by applying a power of 0.5 W / cm ^{2 to} the Si target at a substrate temperature of -8 ° C., an argon flow rate of 300 sccm, an oxygen flow rate of 4.5 sccm and a pressure of 0.2 Pa. Did. The Si target was used for film formation of the SiO ₂ layer, and the Nb target was used for film formation of the Nb ₂ O ₅ layer, and film formation was performed at a substrate temperature of −8 ° C., an argon flow rate of 400 sccm and a pressure of 0.25 Pa. In the film formation of the SiO ₂ layer and the film formation of the Nb ₂ O ₅ layer, the amount of oxygen introduced was controlled so that the film formation mode maintains the transition region by plasma emission monitoring (PEM) control.

Example 2 and Comparative Example 1
The sputter deposition conditions of the primer layer were changed as shown in Table 1, and in Comparative Example 1, the primer layer was deposited without introducing oxygen. In Comparative Example 1, the argon flow rate was changed to 1200 sccm and the pressure was changed to 0.45 Pa. An antireflection film was produced in the same manner as in Example 1 except for the above.

[Evaluation of antireflective film]
(Moisture permeability)
The moisture permeability of the antireflective film was measured in an atmosphere at a temperature of 40 ° C. and a humidity of 90% RH according to JIS K7129: 2008 Annex B. Since the moisture permeability of the film substrate was sufficiently larger than the moisture permeability of the antireflective layer, the moisture permeability of the entire antireflective film was considered to be equal to the moisture permeability of the antireflective layer.

(Film density and composition of thin film)
The film density and composition of the thin film constituting the antireflective layer were measured by the Rutherford backscattering (RBS) method. In the calculation of the film density, the elemental composition using the film thickness determined from transmission electron microscope (TEM) observation of the cross section is a metal (silicon or niobium) based on the elemental composition at the center of the film thickness of each thin film. The total content of oxygen, and argon was calculated as 100 atomic percent.

[Preparation and Evaluation of Durability of Polarizing Plate with Antireflection Layer]
The antireflection films of Examples and Comparative Examples are bonded to one side of a polarizer, and a 30 μm-thick transparent film made of a modified acrylic polymer having a lactone ring structure is bonded to the other side of the polarizer, A polarizing plate with an antireflective layer was produced. As a polarizer, a PVA-based polarizer obtained by stretching a polyvinyl alcohol film having an average degree of polymerization of 2700 and a thickness of 75 μm while being iodine-stained by 6 times was used. For adhesion between a PVA-based polarizer and a transparent film, a polyvinyl alcohol resin containing an acetoacetyl group (average polymerization degree 1200, saponification degree 98.5 mol%, acetoacetylation degree 5 mol%) and methylolmelamine After bonding using a roll bonding machine using an adhesive consisting of an aqueous solution containing a weight ratio of 3: 1, it was dried by heating in an oven.

The obtained polarizing plate with an antireflection layer was charged into a thermostatic chamber at 60 ° C. and 90% RH, and taken out after 72 hours. A commercially available polarizing plate was placed on the backlight, and the change amount Δb ^* of the chromaticity b ^* of the transmitted light before and after the heating / humidifying test was determined.

The film characteristics of each layer of the antireflective layer of Example and Comparative Example, the film forming conditions of the primer layer, the moisture permeability of the antireflective film, and the change amount of the transmitted light b ^* before and after the heating and humidifying test of the polarizing plate with the antireflective layer It is shown in Table 1.

As shown in Table 1, the antireflection films of Example 1 and Example 2 have a moisture permeability smaller than that of Comparative Example 1, and the chromaticity difference before and after the heating / humidifying test of the polarizing plate with an antireflection layer is small. Durability was shown. A clear difference was not seen in the film density of the SiO ₂ layer (film thickness 85 nm) which is the outermost layer between the example and the comparative example.

Since Nb ₂ O ₅ has a moisture permeability larger than that of SiO ₂ , in the alternate stack film of SiO ₂ and Nb ₂ O ₅ , water permeation of the SiO ₂ film is rate-limiting, and the moisture permeability is mainly the SiO ₂ film. Depends on the characteristics of the In Comparative Example 1, although a tendency that the film density of the _Nb 2 _{O 5} layer as compared to Examples 1 and 2 for film formation pressure of _Nb 2 _{O 5} layer is small decreases were observed, _Nb 2 _{O 5} It is considered that the difference in the film density of the layer hardly affects the change in the moisture permeability.

The film formation conditions of the primer layer are different between Examples 1 and 2 and Comparative Example 1, and the film formation is performed at a low argon introduction amount (low pressure) while introducing oxygen. The amount of argon in the film was changed as compared to Example 1. From the results, in the examples, the water vapor barrier property of the antireflective film is improved (the moisture permeability is reduced) by reducing the amount of argon contained in the primer layer, and the durability of the polarizing plate with the antireflective layer is improved. It is thought that

DESCRIPTION OF SYMBOLS 1 Transparent film base material 10 Transparent film 11 Hard-coat layer 5 Anti-reflective layer 50

Primer layer

51, 52, 53, 54 Thin film 8 Polarizer 9 Transparent film 100 Anti-reflective film 101 Polarizing plate with an anti-reflective layer

Claims

An antireflective film comprising an antireflective layer formed of a plurality of thin films having different refractive indexes on one main surface of a transparent film substrate,
The antireflective layer includes a primer layer in contact with the transparent film substrate,
The primer layer has an argon content of 0.01 to 0.5 atomic% or less.
The antireflection film according to claim 1, wherein the primer layer is a silicon oxide layer.
The antireflective film according to claim 2, wherein the antireflective layer comprises a high refractive index layer and a low refractive index layer alternately on the primer layer.
The high refractive index layer is a niobium oxide layer, the low refractive index layer is a silicon oxide layer, and the oxygen content of silicon oxide in the primer layer is less than the oxygen content of silicon oxide in the low refractive index layer. The antireflection film according to claim 3.
The antireflective film according to any one of claims 1 to 4, which has a moisture permeability of 1 g / m 2 · 24 h or less.
The antireflective film according to any one of claims 1 to 5, wherein the transparent film substrate is provided with a hard coat layer on the surface in contact with the primer layer.
A polarizing plate with an antireflection layer comprising the antireflection film according to any one of claims 1 to 6 on one side of a polarizer.
A method of producing an antireflective film according to any one of claims 1 to 6, comprising:
The manufacturing method of the antireflection film in which the said primer layer is formed into a film by sputtering method.
The manufacturing method of the anti-reflective film of Claim 8 in which all the thin films which comprise the said anti-reflective layer are formed into a film by sputtering method.