TWI808402B - Circular polarizing plate with antireflection layer and image display device using the circular polarizer with antireflection layer - Google Patents

Abstract

The present invention provides a circular polarizing plate with an antireflection layer, which has high transmittance and excellent durability in high-temperature and high-humidity environments. As a result, a bright image display device with suppressed display unevenness in high-temperature and high-humidity environments can be realized. A circular polarizing plate with an antireflection layer according to an embodiment of the present invention includes: a polarizing plate including a polarizer; an antireflection layer disposed on one side of the polarizing plate; and a retardation layer disposed on the other side of the polarizing plate. The transmittance of circular polarizing plate with anti-reflection layer is above 45.5%, and the reflectance after heating and humidifying test at 60℃ and 90%RH for 500 hours is below 2.5%.

Description

Circular polarizing plate with anti-reflection layer and image display device using the circular polarizing plate with anti-reflection layer

The present invention relates to a circular polarizing plate with an anti-reflection layer and an image display device using the circular polarizing plate with an anti-reflection layer.

Background technique

In recent years, image display devices typified by liquid crystal display devices and electroluminescent (EL) display devices (eg, organic EL display devices and inorganic EL display devices) have rapidly spread. In an image display device, a circular polarizing plate including a polarizing plate and a retardation plate may be used. From the viewpoint of low power consumption and brightness (brightness) of an image display device (especially an organic EL display device), the circular polarizing plate is preferably a circular polarizing plate with high transmittance. However, circular polarizers with high transmittance may display unevenness (such as streaks) in image display devices under high-temperature and high-humidity environments. Prior art literature patent documents

Patent Document 1: Patent No. 5876441 Patent Document 2: Japanese Patent Laid-Open No. 2014-026266

Summary of the invention The problem to be solved by the invention

The present invention was made to solve the above-mentioned problems, and its main object is to provide a circular polarizing plate with an antireflection layer, which has high transmittance and excellent durability in high-temperature and high-humidity environments. As a result, it can realize a bright image display device with suppressed display unevenness in high-temperature and high-humidity environments. means to solve problems

A circular polarizing plate with an antireflection layer according to an embodiment of the present invention includes: a polarizing plate including a polarizer; an antireflection layer disposed on one side of the polarizing plate; and a retardation layer disposed on the other side of the polarizing plate. The transmittance of the circular polarizing plate with antireflection layer is above 45.5%, and the reflectance after heating and humidifying test at 60°C and 90%RH for 500 hours is below 2.5%. In one embodiment, the polarizer and the protective layer on the antireflection layer side are bonded via a first adhesive layer, the polarizer and the retardation layer are bonded via a second adhesive layer, and at least one of the first adhesive layer and the adhesive of the second adhesive layer is composed of an active energy ray-curable adhesive composition.將組成物總量設為100重量%時，該活性能量線硬化型接著劑組成物含有：SP值為29.0(MJ/m ³ ) ^1/2以上且32.0(MJ/m ³ ) ^1/2以下的活性能量線硬化型化合物(A)0.0重量%~4.0重量%；SP值為18.0(MJ/m ³ ) ^1/2以上且小於21.0(MJ/m ³ ) ^1/2的活性能量線硬化型化合物(B)5.0重量%~98.0重量%；及SP值為21.0(MJ/m ³ ) ^1/2以上且26.0(MJ/m ³ ) ^1/2以下的活性能量線硬化型化合物(C)5.0重量%~98.0重量%。 In one embodiment, the reflectance of the antireflection layer is 1.5% or less. In one embodiment, the Re(550) of the retardation layer is 100nm-200nm, and the angle formed by the slow axis of the retardation layer and the absorption axis of the polarizer is 40°-50° or 130°-140°. In one embodiment, the retardation layer is formed of a stretched resin film, and Re(450)/Re(550) is 0.80 to 1.03. Here, Re(450) and Re(550) are the in-plane retardation measured with light of wavelength 450nm and 550nm at 23°C, respectively. According to another aspect of the present invention, an image display device is provided. The image display device is equipped with the above-mentioned circular polarizing plate with an anti-reflection layer on the viewing side. The circular polarizing plate with an antireflection layer is arranged so that the above antireflection layer becomes the viewing side. The reflectivity of the image display device is below 40%. In one embodiment, the above-mentioned image display device is an organic electroluminescent display device. Invention effect

According to an embodiment of the present invention, by providing an anti-reflection layer on the side that becomes the viewing side when applied to an image display device in a circular polarizing plate, and bonding the protective layer and/or retardation layer of the polarizer and the anti-reflection layer with a specific adhesive, a circular polarizing plate with an anti-reflection layer can be obtained as follows, that is, a high transmittance and excellent durability in a high-temperature and high-humidity environment. As a result, a bright image display device with suppressed display unevenness in a high-temperature and high-humidity environment can be realized.

form for carrying out the invention

Hereinafter, representative embodiments of the present invention will be described, but the present invention is not limited to these embodiments.

(Definition of terms and symbols) The definitions of the terms and symbols in this specification are as follows. (1) Refractive index (nx, ny, nz) "nx" is the refractive index in the direction where the in-plane refractive index is the largest (that is, the direction of the slow axis), "ny" is the refractive index in the direction that is perpendicular to the slow axis in the plane (that is, the direction of the fast axis), and "nz" is the refractive index in the thickness direction. (2) In-plane retardation (Re) "Re(λ)" is the in-plane retardation of the film measured with light of wavelength λnm at 23°C. For example, "Re(450)" is the in-plane retardation of the film measured with light with a wavelength of 450nm at 23°C. When the film thickness is d (nm), Re (λ) can be obtained by the formula: Re=(nx-ny)×d. (3) Phase difference in thickness direction (Rth) "Rth(λ)" is the phase difference in the thickness direction of the film measured with light of wavelength λnm at 23°C. For example, "Rth(450)" is the retardation in the thickness direction of the film measured at 23° C. with light having a wavelength of 450 nm. When the film thickness is d (nm), Rth (λ) is obtained by the formula: Rth=(nx-nz)×d. (4) Nz coefficient The Nz coefficient is obtained by Nz=Rth/Re. (5) angle When an angle is mentioned in this specification, unless otherwise specified, the angle includes angles in both clockwise and counterclockwise directions.

A. Overall structure of circular polarizing plate with anti-reflection layer Fig. 1 is a schematic cross-sectional view of a circular polarizing plate with an antireflection layer according to an embodiment of the present invention. The circular polarizing plate 100 with an anti-reflection layer shown in the figure has: a polarizing plate 10, an anti-reflection layer 30 arranged on one side of the polarizing plate 10 (for example, the side opposite to the image display unit when applied to an image display device, that is, the viewing side), and a retardation layer 40 arranged on the other side of the polarizer 10 (for example, the image display unit side when applied to an image display device). The polarizer 10 includes: a polarizer 11 , and a first protective layer 12 disposed on one side of the polarizer 11 (the side of the anti-reflection layer). Depending on the purpose, a second protective layer (not shown) may also be provided on the retardation layer 40 side of the polarizer 11 . In addition, the protective layers on both sides of the polarizer can also be omitted. For example, when the antireflection layer is usually formed on the substrate as described later, the laminate of the substrate/antireflection layer may function as a protective layer. In this case, the first protective layer 12 may be omitted. The substrate/antireflection layer laminate may further contain a hard coat layer. Therefore, the polarizing plate with a reflective layer can also be configured as follows: omit the protective layers on both sides, and have a polarizer 11, an anti-reflection layer 30 disposed on one side of the polarizer 11, and a retardation layer 40 disposed on the other side of the polarizer 11. In practice, any suitable adhesive layer 50 can be provided as the outermost layer on the opposite side of the retardation layer 40 to the polarizer 10, and the circular polarizer with an anti-reflection layer can be attached to the image display unit.

In an embodiment of the present invention, the transmittance of the circular polarizing plate with an antireflection layer is 45.5% or more, preferably 46.0% or more. The upper limit of the transmittance may be 46.5%, for example. If the transmittance is within this range, an image display device with sufficiently high brightness can be realized. By providing the anti-reflection layer 30 , when the circular polarizing plate is used alone, a high transmittance that is difficult to achieve can be achieved. In an embodiment of the present invention, further, the reflectance of the circular polarizing plate with an antireflection layer after a heating and humidifying test at 60° C. and 90% RH for 500 hours is 2.5% or less, preferably 2.2% or less, more preferably 2.0% or less. The lower limit of the reflectance may be, for example, 1.0%. By controlling the reflectance after the heating and humidification test below a specific value, when the circular polarizing plate with an antireflection layer is applied to an image display device, display unevenness (such as streak unevenness) in a high-temperature and high-humidity environment can be suppressed.

The retardation layer 40 is generally formed of a stretched film of a resin film. The Re(550) of the retardation layer 40 is generally 100 nm to 200 nm. Re(450)/Re(550) of the retardation layer is preferably 0.85~1.03. The angle formed by the slow axis of the retardation layer and the absorption axis of the polarizer 11 is preferably 40°-50°, preferably 42°-48°, more preferably 44°-46°, especially about 45°; or preferably 130°-140°, preferably 132°-138°, more preferably 134°-136°, and most preferably about 135°.

The polarizer 11 and the protective layer 12 on the side of the anti-reflection layer 30 (which may also be the base material for forming the anti-reflection layer) are usually bonded via the first adhesive layer 21 . In addition, the polarizer 11 and the retardation layer 40 are usually bonded via the second adhesive layer 22 . At least one of the adhesives of the first adhesive layer 21 and the second adhesive layer 22 is usually composed of an active energy ray-curable adhesive composition.將組成物總量設為100重量%時，活性能量線硬化型接著劑組成物含有：SP值為29.0(MJ/m ³ ) ^1/2以上且32.0(MJ/m ³ ) ^1/2以下的活性能量線硬化型化合物(A)0.0重量%~4.0重量%；SP值為18.0(MJ/m ³ ) ^1/2以上且小於21.0(MJ/m ³ ) ^1/2的活性能量線硬化型化合物(B)5.0重量%~98.0重量%；及SP值為21.0(MJ/m ³ ) ^1/2以上且26.0(MJ/m ³ ) ^1/2以下的活性能量線硬化型化合物(C)5.0重量%~98.0重量%。 With such a structure, a circular polarizing plate with an antireflection layer having excellent durability in a high-temperature and high-humidity environment (for example, having the above-mentioned reflectance after the heating and humidification test) can be obtained, and as a result, an image display device in which display unevenness is suppressed in a high-temperature and high-humidity environment can be realized. Preferably, at least the first adhesive layer 21 is composed of the above-mentioned active energy ray-curable adhesive composition, and more preferably both the first adhesive layer 21 and the second adhesive layer 22 are composed of the above-mentioned active energy ray-curable adhesive composition. If the above-mentioned adhesive is used, the durability of the polarizing plate under high temperature and high humidity is improved (display unevenness is suppressed). On the other hand, when such a polarizing plate is applied to an image display device, the brightness (brightness) is insufficient.

In one embodiment, the circular polarizing plate with an antireflection layer may further have another retardation layer (not shown) between the retardation layer 40 and the adhesive layer 50 . The other retardation layer usually exhibits a relationship of nz>nx=ny in terms of refractive index characteristics. By providing such another retardation layer, reflection in an oblique direction can be well prevented, and the antireflection function can be widened.

In one embodiment, the circular polarizing plate with an antireflection layer may further have a conductive layer or an isotropic substrate with a conductive layer (not shown). When a conductive layer or an isotropic substrate with a conductive layer is provided, the circular polarizer with an anti-reflection layer can be applied to a so-called internal touch panel type input display device, which is assembled with a touch sensor between the image display unit (such as an organic EL unit) and the polarizer. The conductive layer or the isotropic substrate with the conductive layer is usually disposed between the retardation layer 40 and the adhesive layer 50 . When another retardation layer is provided, the other retardation layer and the conductive layer or the isotropic base material with the conductive layer are generally arranged in order from the retardation layer 40 side.

The circular polarizing plate with anti-reflection layer may also have another retardation layer (not shown). Yet another retardation layer can be provided in combination with another retardation layer, or can be arranged separately (that is, without another retardation layer). The optical characteristics (for example, refractive index characteristics, in-plane retardation, Nz coefficient, photoelastic coefficient), thickness, arrangement position, etc. of the further retardation layer can be appropriately set according to the purpose.

The circular polarizing plate with anti-reflection layer can be in the shape of a single sheet or a strip. The term "elongated" in this specification refers to an elongated shape in which the length is much longer than the width, and includes, for example, an elongated shape whose length is 10 times or more, preferably 20 times or more, relative to the width. The elongated circular polarizing plate with anti-reflection layer can be rolled into a cylinder.

Practically, the release film should be temporarily adhered to the surface of the adhesive layer 50 until the circular polarizing plate with anti-reflection layer is used. By temporarily adhering the release film, the adhesive layer can be protected, and a cylinder of a circular polarizing plate with an antireflection layer can be formed.

Hereinafter, the constituent elements of a circular polarizing plate with an antireflection layer will be described.

B. Polarizer As for the polarizer 11, any appropriate polarizer can be used. For example, the resin film forming the polarizer may be a single-layer resin film or a laminate of two or more layers.

Specific examples of polarizers composed of a single-layer resin film include dyeing and stretching of hydrophilic polymer films such as polyvinyl alcohol (PVA) films, partially formalized PVA films, and ethylene vinyl acetate copolymer partially saponified films using dichroic substances such as iodine or dichroic dyes, and polyene-based alignment films such as dewatered PVA or dehydrochlorinated polyvinyl chloride. From the viewpoint of excellent optical properties, it is preferable to use a polarizer obtained by uniaxially stretching a PVA film dyed with iodine.

The above-mentioned dyeing with iodine is performed, for example, by immersing a PVA-based film in an iodine aqueous solution. The elongation ratio of the above-mentioned uniaxial stretching is preferably 3 to 7 times. The elongation can be carried out after the dyeing treatment, or can be carried out while dyeing. In addition, dyeing may be performed after stretching. Swelling treatment, crosslinking treatment, washing treatment, drying treatment, etc. are performed on the PVA-based film as necessary. For example, immersing the PVA film in water for washing before dyeing can not only clean the dirt and anti-blocking agent on the surface of the PVA film, but also make the PVA film swell and prevent uneven dyeing.

Specific examples of a polarizer obtained using a laminate include a laminate using a resin substrate and a PVA-based resin layer (PVA-based resin film) laminated on the resin substrate, or a laminate obtained from a resin substrate and a PVA-based resin layer coated and formed on the resin substrate. A polarizer obtained by using a laminate of a resin base material and a PVA-based resin layer coated and formed on the resin base material can be produced, for example, by the following method: apply a PVA-based resin solution to the resin base material and dry it to form a PVA-based resin layer on the resin base material to obtain a laminate of the resin base material and the PVA-based resin layer; stretch and dye the laminated body, and use the PVA-based resin layer as a polarizer. In the present embodiment, extending usually includes immersing the laminate in an aqueous solution of boric acid and extending it. Furthermore, if necessary, stretching may further include stretching the laminate in air at a high temperature (for example, 95° C. or higher) before stretching in a boric acid aqueous solution. The obtained resin substrate/polarizer laminate can be used directly (that is, the resin substrate can be used as a protective layer of the polarizer), the resin substrate can be peeled off from the resin substrate/polarizer laminate, and any suitable protective layer depending on the purpose can be used after peeling off the area layer. The detailed manufacturing method of the above-mentioned polarizer is described in, for example, Japanese Patent Laid-Open No. 2012-73580 and Patent No. 6470455. The descriptions of these patent documents are incorporated herein by reference.

The polarizer is preferably composed of a single-layer resin film. According to such a structure, the circular polarizing plate with an antireflection layer which suppresses the retardation unevenness in a high-temperature environment can be obtained by the optimized synergistic effect of the 1st adhesive layer and the 2nd adhesive layer.

The thickness of the polarizer is preferably about 1 μm to 30 μm, preferably about 5 μm to 25 μm. In particular, in order to obtain a polarizer with a thickness of 10 μm or less, it can be applied to a method of manufacturing a thin polarizer disclosed in JP-A-2012-73580 and Patent No. 6470455, etc., which uses a laminate of polyvinyl alcohol-based films formed on a thermoplastic resin substrate as a laminate of the above-mentioned polyvinyl alcohol-based films. When the thickness of the polarizer is within the above range, curling during heating can be well suppressed and good appearance durability during heating can be obtained.

Polarizers are suitable for displaying absorption dichroism at any wavelength from 380nm to 780nm. The single transmittance of the polarizer is, for example, 41.5%-46.0%, preferably 43.0%-46.0%, more preferably 44.5%-46.0%. The single transmittance of the polarizer may be, for example, 44.0% or more, for example, 44.2% or more, for example, 44.6% or more. The degree of polarization of the polarizer is preferably 97.0% or higher, preferably 99.0% or higher, more preferably 99.9% or higher.

C. Protective layer Each of the first protective layer 12 and the second protective layer 13 can be formed of any appropriate film that can be used as a protective layer of a polarizer. Specific examples of the material constituting the main component of the film include cellulose-based resins such as cellulose triacetate (TAC), or transparent resins such as polyester-based, polyvinyl alcohol-based, polycarbonate-based, polyamide-based, polyimide-based, polyether-based, polyvinyl-based, polystyrene-based, norbornene-based, polyolefin-based, (meth)acrylic-based, and acetate-based. Further, thermosetting resins such as (meth)acrylic, urethane, (meth)acrylic urethane, epoxy, and silicone, or ultraviolet curable resins are also mentioned. Moreover, glassy polymers, such as a siloxane polymer, are also mentioned, for example. Moreover, the polymer film described in Unexamined-Japanese-Patent No. 2001-343529 (WO01/37007) can also be used. As the material of the film, for example, a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in the side chain, a thermoplastic resin having a substituted or unsubstituted phenyl group and a nitrile group in the side chain, a resin composition having an alternating copolymer of isobutylene and N-methylmaleimide, and an acrylonitrile-styrene copolymer can be used. The polymer film can be, for example, an extruded product of the above-mentioned resin composition.

The circular polarizing plate with an antireflection layer is usually arranged on the viewing side of the image display device as described later, and the first protective layer 12 is usually arranged on the viewing side. Therefore, surface treatments such as hard coat treatment, antireflection treatment, antisticking treatment, and antiglare treatment may be given to the first protective layer 12 as necessary. Furthermore/alternatively, the first protective layer 12 may be treated to improve the visibility when viewed through polarized sunglasses (typically, imparting (elliptical) polarizing function, imparting super high retardation) as needed. By performing such processing, excellent visibility can be realized even when the display screen is viewed through a polarized lens such as polarized sunglasses. Therefore, the circular polarizing plate with an anti-reflection layer can also be suitably applied to image display devices that can be used outdoors.

The thickness of the first protective layer is usually 300 μm or less, preferably 100 μm or less, more preferably 5 μm to 80 μm, most preferably 10 μm to 60 μm. Furthermore, when performing surface treatment, the thickness of the outer protective layer is the thickness including the thickness of the surface treatment layer.

In one embodiment, the second protective layer 13 is preferably optically isotropic. The term "optically isotropic" in this specification means that the in-plane retardation Re(550) is 0nm~10nm, and the retardation Rth(550) in the thickness direction is -10nm~+10nm.

D. Retardation layer The in-plane retardation Re(550) of the retardation layer represents 100nm~200nm as mentioned above, preferably 110nm~180nm, preferably 120nm~160nm, more preferably 130nm~150nm. That is, the retardation layer functions as a so-called λ/4 plate.

The retardation layer may exhibit inverse dispersion wavelength dependence in which the retardation value increases with the wavelength of the measurement light, or may exhibit flat wavelength dependence in which the retardation value is substantially constant regardless of the wavelength of the measurement light. When the retardation layer exhibits inverse dispersion wavelength dependence, Re(450)/Re(550) is preferably 0.80-0.97, more preferably 0.85-0.95. When the retardation layer exhibits flat wavelength dependence, Re(450)/Re(550) is preferably 0.97-1.03, more preferably 0.98-1.02.

Since the retardation layer has an in-plane retardation as described above, it has a relationship of nx>ny. As long as the retardation layer has the relationship of nx>ny, any appropriate refractive index characteristic can be exhibited. The refractive index characteristics of the retardation layer usually show the relationship of nx>ny≧nz. Furthermore, "ny=nz" here includes not only the situation where ny and nz are completely equal, but also the situation where they are substantially equal. Therefore, there may be a case where ny<nz does not impair the effect of the present invention. The Nz coefficient of the retardation layer is preferably 0.9-2.0, preferably 0.9-1.5, more preferably 0.9-1.2. By satisfying such a relationship, when the circular polarizing plate with an antireflection layer is used in an image display device, a very excellent reflection hue can be achieved.

The thickness of the retardation layer can be set to be most suitable for functioning as a λ/4 plate. In other words, the thickness can be set so that a desired in-plane retardation can be obtained. Specifically, the thickness is preferably less than 70 μm, preferably 45 μm to 60 μm. When the thickness of the retardation layer is within the above range, curling during heating can be well suppressed and curling during bonding can be well adjusted.

The absolute value of the photoelastic coefficient of the retardation layer is preferably below 20×10 ^-12 (m ² /N), preferably 1.0×10 ^-12 (m ² /N) to 15×10 ^-12 (m ² /N), more preferably 2.0×10 ^-12 (m ² /N) to 12×10 ^-12 (m ² /N). If the absolute value of the photoelastic coefficient is within such a range, display unevenness can be suppressed when the circular polarizing plate with an antireflection layer is applied to an image display device.

The retardation layer can be composed of any appropriate resin film that can satisfy the above-mentioned characteristics. Representative examples of the aforementioned resins include polycarbonate resins, polyester carbonate resins, polyester resins, polyvinyl acetal resins, polyarylate resins, cyclic olefin resins, cellulose resins, polyvinyl alcohol resins, polyamide resins, polyimide resins, polyether resins, polystyrene resins, and acrylic resins. These resins may be used alone or in combination (for example, mixing, copolymerization). Generally, the retardation layer can be comprised with polycarbonate-type resin or polyester carbonate-type resin (it may abbreviate to polycarbonate-type resin hereafter).

Any appropriate polycarbonate-based resin can be used for the above-mentioned polycarbonate-based resin. In one embodiment, the polycarbonate-based resin includes: a structural unit derived from a fluorene-based dihydroxy compound, a structural unit derived from an isosorbide-based dihydroxy compound, and a structural unit derived from at least one dihydroxy compound selected from the group consisting of alicyclic diol, alicyclic dimethanol, di-, tri-, or polyethylene glycol, and alkylene diol or spirodiol. Preferably, the polycarbonate resin comprises: a structural unit derived from a fluorene-based dihydroxy compound, a structural unit derived from an isosorbide-based dihydroxy compound, a structural unit derived from alicyclic dimethanol, and/or a structural unit derived from di, tri, or polyethylene glycol; more preferably, it comprises: a structural unit derived from a fluorene-based dihydroxy compound, a structural unit derived from an isosorbide-based dihydroxy compound, and a structural unit derived from di, tri, or polyethylene glycol. The polycarbonate-based resin may contain structural units derived from other dihydroxy compounds as needed. Details of the aforementioned polycarbonate-based resins are described in, for example, JP-A-2014-10291, JP-A-2014-26266, JP-A-2015-212816, JP-A-2015-212817, and JP-A-2015-212818, and these descriptions are incorporated herein by reference.

In another embodiment, the polycarbonate-based resin contains a structural unit derived from a dihydroxy compound having a bond structure represented by the following formula (I). [chemical formula 1]

As a dihydroxy compound, the compound represented by following formula (II) is mentioned, for example. Examples of such dihydroxy compounds include isosorbide, anhydromannitol, and isoiditol in a stereoisomer relationship. These may be used individually or in combination of 2 or more types. [chemical formula 2]

It is also possible to use the above-mentioned dihydroxy compound in combination with another dihydroxy compound. As another dihydroxy compound, an alicyclic dihydroxy compound represented by the following formula (III) can be exemplified. HOCH ₂ -R ¹ -CH ₂ OH ･･･(III) In the formula (III), R ¹ represents a cycloalkylene group having 4 to 20 carbon atoms. Examples of the alicyclic dihydroxy compound include tricyclodecane dimethanol and pentacyclopentadecane dimethanol. These include various isomers in which R ¹ in formula (III) is represented by the following formula (IV) (where n represents 0 or 1). [chemical formula 3]

In one embodiment, the polycarbonate-based resin contains a structural unit represented by the following formula (V). That is, the polycarbonate-based resin may be a copolymer of diphenyl carbonate, isosorbide, and tricyclodecane dimethanol. [chemical formula 4]

The details of such a polycarbonate-based resin are described in, for example, JP 2012-031370 A, and the description in this publication is incorporated herein by reference.

The glass transition temperature of the polycarbonate resin is preferably not less than 110°C and not more than 250°C, preferably not less than 120°C and not more than 230°C. If the glass transition temperature is too low, heat resistance tends to deteriorate, and dimensional changes may occur after film forming. If the glass transition temperature is too high, the forming stability at the time of film forming may deteriorate, and the transparency of the film may be impaired. In addition, glass transition temperature was calculated|required based on JISK7121 (1987).

The molecular weight of polycarbonate resin can be expressed by reduced viscosity. The reduced viscosity uses dichloromethane as a solvent, and the concentration of polycarbonate is precisely adjusted to 0.6g/dL, and is measured with an Ubbelohde viscosity tube at a temperature of 20.0°C±0.1°C. The lower limit of the reduced viscosity is generally preferably 0.30 dL/g, preferably 0.35 dL/g or more. The upper limit of the reduced viscosity is generally preferably 1.20 dL/g, preferably 1.00 dL/g, more preferably 0.80 dL/g. If the reduced viscosity is less than the aforementioned lower limit, there may be a problem that the mechanical strength of the molded product decreases. On the other hand, if the reduced viscosity exceeds the aforementioned upper limit, there may be problems in that the fluidity during molding decreases, and the productivity or formability decreases.

A commercially available film can also be used about a polycarbonate-type resin film. Specific examples of commercially available products include the trade names "Pureace WR-S", "Pureace WR-W", and "Pureace WR-M" manufactured by Teijin Corporation, and the trade name "NRF" manufactured by Nitto Denko Corporation.

The retardation layer can be obtained, for example, by stretching a film formed from the above-mentioned polycarbonate-based resin. As a method of forming a film from a polycarbonate-based resin, any appropriate molding method can be employed. Specific examples include compression molding, transfer molding, injection molding, extrusion molding, blow molding, powder molding, FRP molding, cast coating (such as casting), calendaring, and hot pressing. Extrusion molding method or cast coating method is preferable. The reason for this is that the smoothness of the obtained film can be improved and good optical uniformity can be obtained. The molding conditions can be appropriately set according to the composition and type of resin to be used, desired properties of the retardation layer, and the like. Furthermore, as described above, since there are many film products of polycarbonate-based resins on the market, the commercially available films can also be directly stretched.

The thickness of the resin film (unstretched film) can be set to any appropriate value according to the desired thickness of the retardation layer, desired optical characteristics, stretching conditions described later, and the like. Preferably it is 50 μm to 300 μm.

Any appropriate stretching method and stretching conditions (eg, stretching temperature, stretching ratio, stretching direction) can be used for the above-mentioned stretching. Specifically, various stretching methods such as free-end stretching, fixed-end stretching, free-end shrinkage, and fixed-end shrinkage can be used alone, or simultaneously or sequentially. Regarding the extending direction, it can also be carried out in various directions or dimensions such as the longitudinal direction, the width direction, the thickness direction, and the oblique direction. The stretching temperature is preferably Tg-30°C~Tg+60°C relative to the glass transition temperature (Tg) of the resin film, preferably Tg-10°C~Tg+50°C.

By appropriately selecting the above-mentioned stretching method and stretching conditions, a retardation film having the above-mentioned desired optical characteristics (such as refractive index characteristics, in-plane retardation, and Nz coefficient) can be obtained.

In one embodiment, the retardation film can be produced by uniaxially stretching a resin film or uniaxially stretching a fixed end. As a specific example of the uniaxial stretching of the fixed end, a method of stretching the resin film in the width direction (horizontal direction) while moving in the longitudinal direction is exemplified. The elongation ratio should be 1.1 times to 3.5 times.

In another embodiment, the retardation film can be produced by continuously stretching the elongated resin film obliquely in the direction forming the above-mentioned angle θ with the longitudinal direction. By adopting oblique stretching, a long stretched film with an alignment angle (the slow axis in the direction of angle θ) with the longitudinal direction of the film can be obtained. For example, roll-to-roll can be performed when laminating with a polarizing film, which can simplify the manufacturing steps. Furthermore, the angle θ may be the angle formed by the absorption axis of the polarizing film and the slow axis of the retardation layer in the polarizing plate with a retardation layer. As mentioned above, the angle θ is preferably 40°-50°, preferably 42°-48°, more preferably about 45°.

An example of a stretching machine used for oblique stretching is a tenter stretching machine that can apply feed force, stretching force, or release force at different speeds from left to right in the horizontal and/or vertical directions. The tenter-type stretching machine includes a horizontal uniaxial stretching machine, a simultaneous biaxial stretching machine, and the like, but any appropriate stretching machine can be used as long as it can continuously stretch the elongated resin film obliquely.

By appropriately controlling the left and right speeds in the stretching machine, a retardation layer (substantially a long retardation film) having the desired in-plane retardation and a slow axis in the desired direction can be obtained.

The stretching temperature of the above-mentioned film can be changed according to the desired in-plane retardation value and thickness of the retardation layer, the type of resin used, the thickness of the film used, the stretching ratio, and the like. Specifically, the stretching temperature is preferably Tg-30°C~Tg+30°C, more preferably Tg-15°C~Tg+20°C, most preferably Tg-10°C~Tg+15°C. By stretching at this temperature, a retardation layer having appropriate characteristics can be obtained in the present invention. In addition, Tg is the glass transition temperature of the constituent material of a thin film.

E. Anti-reflection layer The antireflection layer 30 is usually a hardened layer of an ionizing radiation curable resin composition. As mentioned above, by providing an anti-reflection layer, a high transmittance that is difficult to achieve can be achieved when a circular polarizing plate is used alone. The reflectance of the antireflection layer is preferably 1.5% or less, preferably 1.3% or less, more preferably 1.0% or less. The smaller the reflectivity, the better, and its lower limit may be 0.2%, for example. If the reflectance is within this range, reflection of external light and the like can be prevented.

The ionizing radiation curable resin composition contains an ionizing radiation curable resin. Depending on the purpose, the radiation-curable resin composition may further include reactive diluents, fluorine-containing element additives, hollow particles and/or solid particles.

The ionizing radiation curable resin generally includes thermosetting resins, ultraviolet curable resins, light (visible light) curable resins, and electron beam curable resins. Examples of ionizing radiation-curable resins include silicone resins, polyester resins, polyether resins, epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, and polythiol polyene resins. Also, for example, the ionizing radiation-curable resin may be a curable compound having an acrylate group and/or a methacrylate group that is cured by heat, light (ultraviolet rays, etc.), electron beams, or the like. Specific examples include oligomers and prepolymers such as acrylates and/or methacrylates of polyfunctional compounds such as polyhydric alcohols. The ionizing radiation curable resins may be used alone or in combination of two or more.

The weight average molecular weight before curing of the ionizing radiation curable resin may be, for example, 100 or more, 300 or more, 500 or more, 1,000 or more, or 2,000 or more, and may be 100,000 or less, 70,000 or less, 50,000 or less, 30,000 or less, or 10,000 or less. The larger the weight average molecular weight before hardening, the lower the hardness, but it tends to be less prone to cracking when bent. The smaller the weight average molecular weight before curing, the higher the intermolecular crosslink density and the higher the hardness tends to be.

Reactive diluents generally contain acrylate and/or methacrylate groups. As the reactive diluent, for example, the reactive diluent described in JP-A-2008-88309 can be used. Specific examples of the reactive diluent include monofunctional acrylates, monofunctional methacrylates, polyfunctional acrylates, and polyfunctional methacrylates. Preferable are trifunctional or higher acrylates and trifunctional or higher methacrylates. As for the reactive diluent, for example, butylene glycol glyceryl ether diacrylate, acrylate of isocyanuric acid, methacrylate of isocyanuric acid, etc. are also mentioned. Reactive diluents may be used alone or in combination of two or more.

As for the fluorine-containing element additive, any appropriate compound can be used. The fluorine-containing additive can be, for example, an organic or inorganic compound containing fluorine in its molecule. Regarding the organic compound, for example, a fluorine-containing antifouling coating agent, a fluorine-containing acrylic compound, a fluorine/silicon-containing acrylic compound, and the like are mentioned. As an organic compound, a commercial item can also be used. As a specific example, the brand name "KY-1203" by Shin-Etsu Chemical Co., Ltd., and the brand name "MEGAFUCK" by DIC Co., Ltd. are mentioned. As the inorganic compound, any appropriate fluorine-containing inorganic compound can be used.

The blending amount of the fluorine-containing element additive is relative to 100 parts by weight of the ionizing radiation-curable resin, for example, it may be 0.05 parts by weight or more, 0.1 parts by weight or more, 0.15 parts by weight or more, 0.20 parts by weight or more, or 0.25 parts by weight or more, or it may be 20 parts by weight or less, 15 parts by weight or less, 10 parts by weight or less, 5 parts by weight or less, or 3 parts by weight or less.

As for the hollow particles, any appropriate hollow particles may be used. Specific examples include silicon oxide particles, acrylic particles, and acrylic-styrene copolymer particles. As the hollow particles, commercially available ones can also be used. Specific examples of commercially available silicon oxide particles include "THRURIA 5320" and "THURIA 4320" manufactured by Nikki Catalytic Chemicals Co., Ltd. The weight average particle size of the hollow particles can be, for example, 30 nm or more, 40 nm or more, 50 nm or more, 60 nm or more, or 70 nm or more, and can also be 150 nm or less, 140 nm or less, 130 nm or less, 120 nm or less, or 110 nm or less. Regarding the shape of the hollow particles, any appropriate shape can be adopted. The shape of the hollow particles may be, for example, bead-like, roughly spherical, or irregular shapes such as powder. It is preferably substantially spherical, more preferably substantially spherical with an aspect ratio of 1.5 or less, and most preferably substantially spherical. By formulating the hollow particles, an anti-reflection layer with low refractive index and good anti-reflection properties can be obtained. The blending amount of the hollow particles may be, for example, 30 parts by weight or more, 50 parts by weight or more, 70 parts by weight or more, 90 parts by weight or more, or 100 parts by weight or more, and 300 parts by weight or less, 270 parts by weight or less, 250 parts by weight or less, 200 parts by weight or less, or 180 parts by weight or less, relative to 100 parts by weight of the free radiation curable resin. If the blending amount is within this range, an antireflection layer having excellent mechanical properties and a low refractive index can be obtained.

As for the solid particles, any suitable solid particles may be used. Specific examples include silicon oxide particles, zirconia particles, and titanium particles. As solid particles, commercially available ones can also be used. Specific examples of commercially available silicon oxide particles include "MEK-2140Z-AC", "MIBK-ST", and "IPA-ST", manufactured by Nissan Chemical Industry Co., Ltd. The weight average particle size of solid particles can be, for example, 5 nm or more, 10 nm or more, 15 nm or more, 20 nm or more, or 25 nm or more, and 3300 nm or less, 250 nm or less, 200 nm or less, 150 nm or less, or 100 nm or less. As for the shape of the solid particles, any appropriate shape can be adopted. The shape of the solid particles may be, for example, bead-like, roughly spherical, or irregular shapes such as powder. It is preferably substantially spherical, more preferably substantially spherical with an aspect ratio of 1.5 or less, and most preferably substantially spherical. By formulating solid particles, the fluorine-containing element additive tends to exist on the surface of the anti-reflection layer, and as a result, an anti-reflection layer with low refractive index and good anti-reflection properties can be obtained. The blending amount of the solid particles is, for example, not less than 5 parts by weight, not less than 10 parts by weight, not less than 15 parts by weight, not less than 20 parts by weight, or not less than 25 parts by weight, and not more than 150 parts by weight, not more than 120 parts by weight, not more than 100 parts by weight, or not more than 80 parts by weight relative to 100 parts by weight of the free radiation curable resin. When the compounding amount is within this range, an antireflection layer having an excellent balance of mechanical properties, refractive index, and transparency can be obtained.

The antireflection layer can generally be formed by applying a coating solution for forming an antireflection layer obtained by diluting an ionizing radiation curable resin composition with a diluent solvent; drying the coating film; and curing the dried coating film.

As the diluting solvent, any appropriate solvent can be used depending on the free radiation curable resin. Examples of dilution solvents include alcohols such as methanol, ethanol, isopropanol, butanol, TBA (tertiary butanol), and 2-methoxyethanol; ketones such as acetone, methyl ethyl ketone, MIBK (methyl isobutyl ketone), and cyclopentanone; esters such as methyl acetate, ethyl acetate, butyl acetate, and PMA (propylene glycol monomethyl ether acetate); ethers such as diisopropyl ether and propylene glycol monomethyl ether; glycols such as ethylene glycol and propylene glycol; Cellosolves such as cellulosic agent and butyl cellosolve; aliphatic hydrocarbons such as hexane, heptane and octane; aromatic hydrocarbons such as benzene, toluene and xylene. The diluting solvent may be used alone or in combination of two or more. Polarity can be adjusted by mixing a plurality of solvents in any appropriate ratio according to the purpose.

The diluting solvent may be, for example, a mixed solvent including MIBK and PMA. The mixing ratio at this time can be appropriately set according to the purpose. The mixing ratio is relative to 100 parts by weight of MIBK. For example, PMA may be 20 parts by weight or more, 50 parts by weight or more, 100 parts by weight or more, 150 parts by weight or more, or 200 parts by weight or more, and may be 400 parts by weight or less, 350 parts by weight or less, 300 parts by weight or less, or 250 parts by weight or less.

The diluting solvent may be, for example, a mixed solvent containing TBA in addition to MIBK and PMA. The mixing ratio at this time can also be set appropriately according to the purpose. The mixing ratio is relative to 100 parts by weight of MIBK. PMA can be, for example, more than 10 parts by weight, more than 30 parts by weight, more than 50 parts by weight, more than 80 parts by weight, or more than 100 parts by weight, and can be less than 200 parts by weight, less than 180 parts by weight, less than 150 parts by weight, less than 130 parts by weight, or less than 110 parts by weight; And it may be 200 parts by weight or less, 180 parts by weight or less, 150 parts by weight or less, 130 parts by weight or less, or 110 parts by weight or less.

The solid content concentration of the coating liquid may be, for example, 0.1% by weight or more, 0.3% by weight or more, 0.5% by weight or more, 1.0% by weight or more, or 1.5% by weight or more, and may be 20% by weight or less, 15% by weight or less, 10% by weight or less, 5% by weight or less, or 3% by weight or less. If the solid content concentration is within this range, it can achieve both coating performance (such as wetting, leveling) and prevent the appearance of the coating film (such as uneven drying, whitening).

A hardener may also be added to the coating liquid as needed. As the hardener, any appropriate polymerization initiator (for example, a thermal polymerization initiator, a photopolymerization initiator, etc.) can be used. The amount of the hardener added is, for example, not less than 0.5 parts by weight, not less than 1.0 parts by weight, not less than 1.5 parts by weight, not less than 2.0 parts by weight, or not less than 2.5 parts by weight, and may be not more than 15 parts by weight, not more than 13 parts by weight, not more than 10 parts by weight, not more than 7 parts by weight, or not more than 5 parts by weight relative to 100 parts by weight of the free radiation curable resin.

The anti-reflection layer is usually formed behind any suitable substrate, and then laminated on the polarizer or polarizing plate via any suitable adhesive layer or adhesive layer. First, the coating liquid is coated on the substrate. As for the coating method, any appropriate method may be employed. Specific examples include a jet coating method, a die coating method, a spin coating method, a spray coating method, a gravure coating method, a roll coating method, and a bar coating method. The coating amount of the coating liquid can be appropriately set according to the thickness of the antireflection layer to be formed. The thickness of the antireflection layer to be formed can be, for example, 0.1 μm or more, 0.3 μm or more, 0.5 μm or more, 1.0 μm or more, or 2.0 μm or more, and can be 50 μm or less, 40 μm or less, 30 μm or less, 20 μm or less, or 10 μm or less.

Next, the applied coating liquid is dried to form a coating film. The drying temperature can be appropriately set according to the purpose. The drying temperature may be, for example, 30°C or higher, 40°C or higher, 50°C or higher, 60°C or higher, 70°C or higher, 80°C or higher, 90°C or higher, or 100°C or higher, and may be 200°C or lower, 190°C or lower, 180°C or lower, 170°C or lower, 160°C or lower, 150°C or lower, 140°C or lower, 135°C or lower, 130°C or lower, 120°C or lower, or 110°C or lower. The drying time can also be set appropriately according to the purpose. The drying time may be, for example, 30 seconds or more, 40 seconds or more, 50 seconds or more, or 60 seconds or more, and may be 150 seconds or less, 130 seconds or less, 110 seconds or less, or 90 seconds or less.

Next, the coating film is cured. Hardening can be performed by heating, light irradiation, etc., for example. The light used for photoirradiation may be, for example, ultraviolet rays or visible light. The light source for light irradiation may be, for example, a high-pressure mercury lamp. The radiation dose of the energy ray source during ultraviolet curing is preferably 50mJ/cm ² ~500mJ/cm ² based on the cumulative exposure dose at the ultraviolet wavelength of 365nm. When the irradiation dose is 50 mJ/cm ² or more, hardening tends to proceed sufficiently, and the hardness of the formed antireflection layer tends to increase. If the irradiation dose is 500 mJ/cm ² or less, the formed antireflection layer can be prevented from being colored.

F. First Adhesive Layer and Second Adhesive Layer As described above, at least one of the adhesives of the first adhesive layer 21 and the second adhesive layer 22 is usually composed of an active energy ray-curable adhesive composition.將組成物總量設為100重量%時，活性能量線硬化型接著劑組成物含有：SP值為29.0(MJ/m ³ ) ^1/2以上且32.0(MJ/m ³ ) ^1/2以下的活性能量線硬化型化合物(A)0.0重量%~4.0重量%；SP值為18.0(MJ/m ³ ) ^1/2以上且小於21.0(MJ/m ³ ) ^1/2的活性能量線硬化型化合物(B)5.0重量%~98.0重量%；及SP值為21.0(MJ/m ³ ) ^1/2以上且26.0(MJ/m ³ ) ^1/2以下的活性能量線硬化型化合物(C)5.0重量%~98.0重量%。 Preferably, at least the first adhesive layer 21 is composed of the above-mentioned active energy ray-curable adhesive composition, and more preferably both the first adhesive layer 21 and the second adhesive layer 22 are composed of the above-mentioned active energy ray-curable adhesive composition. In addition, when only one of the first adhesive layer 21 or the second adhesive layer 22 is composed of the above active energy ray-curable adhesive composition, the other adhesive layer may be composed of any appropriate adhesive.

Hereinafter, the above-mentioned active energy ray-curable adhesive composition will be described.

Specific examples of the active energy ray-curable compound (A) include hydroxyethylacrylamide (SP value 29.5) and N-methylolacrylamide (SP value 31.5). When the total amount of the composition is taken as 100% by weight, the content of the compound (A) is preferably 4.0% by weight or less, preferably 2.0% by weight, more preferably 1.5% by weight, and most preferably 1.0% by weight. The composition preferably does not contain the compound (A).

Specific examples of the active energy ray-curing compound (B) include: tripropylene glycol diacrylate (SP value 19.0), 1,9-nonanediol diacrylate (SP value 19.2), tricyclodecane dimethanol diacrylate (SP value 20.3), cyclic trimethylolpropane formal acrylate (SP value 19.1), dioxane diol diacrylate (SP value 19.4), EO-modified diglycerin tetraacrylate (SP value 20 .9). A commercial item can also be used about a compound (B). Specific examples of commercially available products include: ARONIX M-220 (manufactured by Toagosei Co., Ltd., SP value 19.0), LIGHTACRYLATE 1,9ND-A (manufactured by Kyoeisha Chemical Co., Ltd., SP value 19.2), LIGHTACRYLATE DGE-4A (manufactured by Kyoeisha Chemical Co., Ltd., SP value 20.9), LIGHTACRYLATE DCP-A (manufactured by Kyoeisha Chemical Co., Ltd., SP value 20. 3), SR-531 (manufactured by Sartomer, SP value 19.1), CD-536 (manufactured by Sartomer, SP value 19.4). When the total amount of the composition is taken as 100% by weight, the content of the compound (B) is preferably 20% by weight to 80% by weight, more preferably 25% by weight to 70% by weight.

Specific examples of the active energy ray-curable compound (C) include acrylmorpholine (SP value 22.9), N-methoxymethacrylamide (SP value 22.9), and N-ethoxymethacrylamide (SP value 22.3). A commercial item can also be used about a compound (C). Specific examples of commercially available products include ACMO (manufactured by Kohin Co., Ltd., SP value 22.9), WASSMER (transliteration) 2MA (manufactured by Kasano Kosan Co., Ltd., SP value 22.9), WASSMER EMA (manufactured by Kasano Kosan Co., Ltd., SP value 22.3), and WASSMER 3MA (manufactured by Kasano Kosan Co., Ltd., SP value 22.4). When the total amount of the composition is taken as 100% by weight, the content of the compound (C) is preferably 20% by weight to 80% by weight, more preferably 25% by weight to 70% by weight.

The SP value (solubility parameter) can be calculated by the Fedors calculation method [refer to "Polymer Eng. & Sci.", Vol. 14, No. 2 (1974), pp. 148-154].

The active energy ray-curable adhesive composition may further contain an acrylic oligomer (D) obtained by polymerizing a (meth)acrylic monomer. By containing an oligomer, the adhesive force of an antireflection layer and a polarizing plate (substantially a 1st protective layer), and/or the adhesive force of an antireflection layer and a retardation layer can be improved. When the total amount of the composition is 100% by weight, the content of the oligomer (D) is preferably at least 3.0% by weight, preferably at least 5.0% by weight. On the other hand, the content is preferably not more than 25% by weight, preferably not more than 15% by weight. Within this range, curing shrinkage (excessive curing) and poor curing (insufficient curing) can be suppressed. The weight average molecular weight Mw of the oligomer (D) is preferably 15,000 or less, preferably 10,000 or less, more preferably 5,000 or less. On the other hand, the weight average molecular weight Mw is preferably 500 or more, preferably 1000 or more, more preferably 1500 or more.

The active energy ray-curable adhesive composition may further contain a radical polymerization initiator (E) having a hydrogen abstraction function. As a radical polymerization initiator (E), a thioxanthone radical polymerization initiator and a benzophenone radical polymerization initiator are mentioned, for example. Preferred is diethylthioxanthone.

The thickness of the first adhesive layer and/or the second adhesive layer composed of the active energy ray-curable adhesive composition is preferably 0.01 μm to 3.0 μm, preferably 0.1 μm to 2.5 μm, more preferably 0.5 μm to 1.5 μm.

An easy-adhesive layer may be formed between the polarizing plate and the first adhesive layer and/or the second adhesive layer.

The details of the above-mentioned active energy ray-curable adhesive composition and the composition forming an easily-adhesive layer are described in, for example, Japanese Patent Application Laid-Open No. 2019-147865. The description of this publication is incorporated in this specification as a reference.

G. Image display device The circular polarizing plate with an anti-reflection layer described in items A to F above can be applied to an image display device. Therefore, the embodiment of the present invention also includes an image display device using such a circular polarizing plate with an antireflection layer. The image display device according to the embodiment of the present invention usually has the circular polarizing plate with anti-reflection layer described in the above items A to F on the viewing side. The circular polarizing plate with anti-reflection layer is arranged so that the above-mentioned anti-reflection layer becomes the viewing side. The reflectivity of the image display device should be below 40%. In an image display device having such a reflectivity, the effect of the circular polarizing plate with an anti-reflection layer described in the above items A to F is remarkable. Specifically, as follows. If the reflectivity of the image display device is low, the reflection of the displayed image can be reduced, but on the other hand, display unevenness (such as stripes) is not easy to be seen on the image display device in a high-temperature and high-humidity environment. Representative examples of image display devices include liquid crystal display devices and organic electroluminescence (EL) display devices. An organic EL display device is preferable. [Example]

Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples. In addition, the measurement method of each characteristic is as follows.

(1) Transmittance The transmittance of the circular polarizing plates with anti-reflection layers obtained in Examples and Comparative Examples was measured using an ultraviolet-visible spectrometer (V-7100 manufactured by JASCO Corporation). In addition, the single-body transmittance is measured by JIS Z 8701 with a 2-degree field of view (C light source), and the Y value after the sensitivity correction is performed. (2) reflectivity The circular polarizing plates with anti-reflection layers obtained in Examples and Comparative Examples were cut out to specific dimensions, and corona treatment was performed on the surface of the retardation layer. The corona-treated surface of the circular polarizing plate with an antireflection layer was bonded to an alkali-free glass plate via an acrylic adhesive (20 μm) to produce a laminate. This laminate was subjected to a heating and humidifying test at 60° C. and 90% RH for 500 hours. The laminated body after the heating and humidifying test was mounted on the organic EL device substitute so that the glass plate faces to be used as a test sample. The front reflectance of this test sample was measured using the spectrophotometer "CM-2600d" manufactured by Konica Minolta. The front reflectance is measured by SCI method. In addition, a substitute organic EL display device was produced as follows. An aluminum vapor-deposition film (manufactured by Toray Film Processing Co., Ltd., trade name "DMS vapor deposition X-42", thickness 50 μm) was bonded to an acrylic plate with an adhesive, and this was used as a substitute for an organic EL display device. (3) Uneven display With respect to the test sample prepared in the same manner as above (1), the display unevenness (streaks, color unevenness, brightness unevenness, etc.) of the test sample was visually observed under a fluorescent lamp, and the evaluation was performed according to the following criteria. ○: No display unevenness was observed in any of the frontal and oblique directions △: Display unevenness was not observed in the front direction, but display unevenness was observed in the oblique direction ╳: Display unevenness is observed in any direction of the front direction and the oblique direction (4) Brightness The organic EL panel was taken out from an organic EL display (manufactured by Samsung, product name "Galaxy S5"), and the polarizing film attached to the organic EL panel was peeled off, and attached to the circular polarizing plates obtained in Examples and Comparative Examples to obtain an organic EL display device. A white image was displayed on the obtained organic EL display device, and the front luminance (cd) was measured using a spectroradiometer manufactured by TOPCON (trade name "SR-UL1R").

[Manufacturing example 1: Making a polarizing plate] (production of polarizer) A polyvinyl alcohol film with a thickness of 45 μm and an average degree of polymerization of 2400 and a degree of saponification of 99.9 mol% was immersed in warm water at 30°C for 60 seconds to swell. Next, the film was dyed while being dipped in an aqueous solution with a concentration of 0.3% of iodine/potassium iodide (weight ratio = 1/7), stretching to 2.6 times. Then, it stretched so that the total stretching ratio might become 6 times in 65 degreeC 4 weight% boric-acid aqueous solution. After stretching, it was dried in an oven at 55° C. for 1 minute to obtain a PVA-based polarizer. The polarizer had a thickness of 18 μm and a moisture content of 15% by weight.

(Production of Polarizing Plate) A cycloolefin-based film (manufactured by ZEON Japan, ZF-12, 23 μm) was attached as a protective layer to the surface of the obtained polarizer (the surface opposite to the resin substrate) via a UV-curable adhesive. Specifically, it was applied so that the total thickness of the curable adhesive was approximately 1.0 μm, and bonded using a roll press. After that, UV rays are irradiated from the side of the cycloolefin-based film to harden the adhesive. Next, the resin substrate was peeled off to obtain a polarizing plate having a cycloolefin-based film (protective layer)/polarizer structure.

[Manufacturing Example 2: Fabrication of a retardation film constituting a retardation layer] Polymerization was performed using a batch type polymerization apparatus consisting of a vertical reactor equipped with stirring blades and a reflux cooler controlled at 100°C. Add 29.60 parts by mass (0.046mol) of bis[9-(2-phenoxycarbonylethyl)fluorene-9-yl]methane, 29.21 parts by mass (0.200mol) of isosorbide (ISB), 42.28 parts by mass (0.139mol) of spirodiol (SPG), 63.77 parts by mass (0.298mol) of diphenyl carbonate (DPC) and 1.1 parts by mass of calcium acetate monohydrate as a catalyst. 9×10 ^-2 parts by mass (6.78×10 ^-5 mol). After reducing the pressure in the reactor and replacing it with nitrogen, it was heated with a heat medium, and stirring was started when the internal temperature became 100°C. 40 minutes after starting the temperature rise, the internal temperature was brought to 220° C., and while controlling to maintain the temperature, the pressure was reduced, and it took 90 minutes after reaching 220° C. to reach 13.3 kPa. Lead the by-product phenol vapor together with the polymerization reaction to the reflux cooler at 100°C, so that a certain amount of monomer components contained in the phenol vapor can be returned to the reactor, and the uncondensed phenol vapor is led to the 45°C condenser for recovery. Nitrogen gas was introduced into the first reactor, and once the pressure was restored to atmospheric pressure, the oligomerized reaction liquid in the first reactor was transferred to the second reactor. Next, temperature rise and pressure reduction in the second reactor were started, and it took 50 minutes to achieve an internal temperature of 240° C. and a pressure of 0.2 kPa. Then, polymerization is performed until a predetermined stirring power is obtained. When the specified power is reached, nitrogen gas is introduced into the reactor for repressurization, and the resulting polyester carbonate resin is extruded in water, and granules are obtained after strand cutting.

After vacuum-drying the obtained polyester carbonate resin (pellet) at 80°C for 5 hours, a long resin film with a thickness of 135 μm was produced using a film forming device equipped with a single-screw extruder (manufactured by Toshiba Machine Co., Ltd., cylinder set temperature: 250°C), a T-die (width 200mm, set temperature: 250°C), a chill roll (set temperature: 120~130°C) and a coiler. The obtained elongated resin film was stretched in the width direction at a stretching temperature of 133° C. and a stretching ratio of 2.8 times to obtain a retardation film I with a thickness of 48 μm. The Re(550) of the obtained retardation film was 141 nm, the Re(450)/Re(550) was 0.82, and the Nz coefficient was 1.12.

[Manufacturing example 3: Fabrication of a retardation film constituting a retardation layer] 81.98 parts by mass of isosorbide (hereinafter referred to as "ISB" in some cases), 47.19 parts by mass of tricyclodecane dimethanol (hereinafter referred to as "TCDDM" in some cases), 175.1 parts by mass of diphenyl carbonate (hereinafter referred to as "DPC" in some cases) and 0.979 parts by mass of cesium carbonate 0.2 mass % aqueous solution as a catalyst were put into the reaction container. It is necessary to dissolve the raw materials while stirring (about 15 minutes). Next, while increasing the pressure from normal pressure to 13.3 kPa and raising the temperature of the heating tank to 190° C. over 1 hour, generated phenol was discharged out of the reaction vessel. After keeping the entire reaction vessel at 190° C. for 15 minutes, as a second step, the pressure inside the reaction vessel was set to 6.67 kPa, the temperature of the heating tank was raised to 230° C. over 15 minutes, and the generated phenol was discharged out of the reaction vessel. As the stirring torque of the stirrer increases, it takes 8 minutes to raise the temperature to 250°C to further discharge the generated phenol, so that the pressure in the reaction vessel reaches below 0.200kPa. After the specified stirring torque is reached, the reaction is terminated, and the resulting reactant is extruded in water to obtain polycarbonate copolymer particles.

After vacuum-drying the obtained pellets at 80°C for 5 hours, a resin film was produced using a film-forming device equipped with a single-screw extruder (manufactured by Toshiba Machine Co., Ltd., cylinder set temperature: 250°C), a T-die (width 200mm, set temperature: 250°C), a chill roll (set temperature: 120-130°C) and a coiler. The obtained elongated resin film was stretched in an oblique direction at a stretching temperature of 140° C. and a stretching ratio of 2.2 times to obtain a retardation film II with a thickness of 30 μm. Re(550) of the obtained retardation film was 144 nm, Re(450)/Re(550) was 1.02, and Nz coefficient was 1.2.

[Manufacture Example 4: Production of antireflection layer] [Production Example 4-1: Production of hard coat layer] As the resin contained in the hard coat layer, 100 parts by weight of ultraviolet curable urethane acrylate resin (manufactured by DIC Co., Ltd., trade name "UNIDIC 17-806", solid content 80%) was prepared. 3 parts by weight of a photopolymerization initiator (manufactured by BASF Corporation, trade name "OMNIRAD907") and 0.01 part by weight of a leveling agent (manufactured by DIC Co., Ltd., trade name "GRANDIC PC4100", solid content 10%) were mixed with 100 parts by weight of the solid content of the resin. This mixture was diluted with butyl acetate/cyclopentanone mixed solvent (80/20 by weight) so that the solid content concentration might become 40%, and the hard-coat layer formation material (coating liquid) was prepared. On the surface of the substrate (TAC film with a thickness of 60 μm), the above-mentioned coating liquid was coated with a wire bar. Heat the applied coating solution at 80°C for 1 minute to dry it to form a coating film. Use a high-pressure mercury lamp to irradiate the dried coating film with ultraviolet rays with a cumulative light intensity of 300mJ/cm ² for hardening treatment to obtain a hard coating film (hard coating) on the substrate.

[Manufacturing Example 4-2: Fabrication of anti-reflection layer] 100 parts by weight of polyfunctional acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name "Viscoat #300", solid content 100% by weight) containing neopentylthritol triacrylate as a main component, hollow nano-silica particles (manufactured by Nikki Shokubai Chemical Industry Co., Ltd., trade name "THRURIA 5320", solid content 20 wt%, weight average particle diameter 75nm) 100 parts by weight, solid nano-silica particles (manufactured by Nissan Chemical Industry Co., Ltd., A product name "MEK-2140Z-AC", 40 parts by weight of a solid content of 30% by weight, a weight average particle diameter of 10 nm), 12 parts by weight of an additive containing a fluorine element (manufactured by Shin-Etsu Chemical Co., Ltd., product name "KY-1203", a solid content of 20% by weight) and 3 parts by weight of a photopolymerization initiator (manufactured by IGM Resins B.V., a product name of "Omnirad907", a solid content of 100% by weight) were mixed. A mixed solvent as a diluting solvent was added to the mixture so that the overall solid content was 4% by weight, and stirred to prepare a coating liquid for forming an antireflective layer. The mixed solvent was a mixture of TBA (tertiary butanol), MIBK (methyl isobutyl ketone), and PMA (propylene glycol monomethyl ether acetate) at a weight ratio of 60:25:15.

On the hard coat surface of the substrate/hard coat layer laminate obtained in Production Example 4-1, the coating liquid for forming an antireflection layer obtained in Production Example 4-2 was coated with a wire bar. Heat the applied coating solution at 80°C for 1 minute, and make it dry to form a coating film. Use a high-pressure mercury lamp to irradiate the dried coating film with ultraviolet rays with a cumulative light intensity of 300mJ/cm ² for hardening treatment to form an anti-reflection layer. In this way, a laminate of base material/hard coat (HC) layer/antireflection layer was produced.

[Manufacturing Example 5: Preparation of an adhesive composition constituting an adhesive layer] 45 parts by mass of acryloylmorpholine (manufactured by Kohin Corporation, trade name "ACMO", SP value: 22.9), 41 parts by mass of 1,9-nonanediol diacrylate (trade name "LIGHTACRYLATE 1,9ND-A", manufactured by Kyoeisha Chemical Co., Ltd.), and 10 parts by mass of acrylic low polymer (trade name "ARUFON UG4010", manufactured by Toagosei Co., Ltd.) polymerized by (meth)acrylic acid monomers were used as photopolymerization initiators. An adhesive agent composition was prepared by mixing 1.5 parts by mass of diethylthioxanthone (trade name "KAYACURE DETX-S", manufactured by Nippon Kayaku Co., Ltd.) and 2.5 parts by mass of 2-methyl-1-(4-methylphenylthio)-2-morpholine propane-1-one (trade name "IRGACURE907", manufactured by BASF Corporation) as a photopolymerization initiator, and stirring at 50° C. for 1 hour. For convenience, this adhesive composition is referred to as a high-durability adhesive composition.

[Manufacturing Example 6: Preparation of an adhesive composition constituting an adhesive layer] As an adhesive, 12 parts by weight of hydroxyethylacrylamide (manufactured by Koujin Co., Ltd., trade name "HEAA", SP value: 29.5), acrylylmorpholine (manufactured by Koujin Co., Ltd., trade name "ACMO", SP value: 22.9) 35 parts by mass, 1,9-nonanediol diacrylate (trade name "LIGHTACRYLATE 1,9ND-A", manufactured by Kyoeisha Chemical Co., Ltd.) 40 parts by mass, acrylic low polymer (trade name "ARUFON UG4010", manufactured by Toagosei Co., Ltd.), 10 parts by weight of KAYACURE DETX-S ((2,4-diethylthioxanthone), manufactured by Nippon Kayaku Co., Ltd.) as a photopolymerization initiator, and photosensitizer IRGACURE907 (2-methyl-1-(4-methylphenylthio)-2-morpholinopropan-1-one, trade name "IRGACURE907", manufactured by BASF Corporation) 1 part by weight was mixed at the above ratio, and stirred at 50° C. for 1 hour to prepare an adhesive composition. For convenience, this adhesive composition is referred to as a general adhesive composition.

[Manufacturing Example 7: Preparation of a composition constituting an easy-adhesive layer (easy-adhesive composition)] Mix 50 parts by mass of acrylylmorpholine (manufactured by Kohin Co., trade name "ACMO", SP value: 22.9) and 0.9 parts by mass of 3-acrylamide phenylboronic acid (manufactured by Junsei Chemical Co., Ltd.), and stir the obtained mixture at 25°C for 30 minutes. Then, 48.3 parts by mass of water and 0.8 parts by mass of a leveling agent (manufactured by Nissin Chemical Industry Co., Ltd., trade name "ALFINE EXP.4123") are mixed at 25°C. Stir for 10 minutes to prepare an easy-to-adhesive composition.

[Examples 1-4 and Comparative Examples 1-5] Combining the polarizing plate, retardation film (retardation layer), antireflection layer, and adhesive (the first adhesive layer and the second adhesive layer) as shown in Table 1, a circular polarizing plate with an antireflection layer as shown in Figure 1 (but without the first and second protective layers) was produced. The specific production method is as follows. The easy-adhesive composition of Production Example 7 was coated on both sides of the polarizer with an initial thickness of 1100 nm. On the other hand, a first adhesive layer was formed on the surface of the base material of the laminate obtained in Production Example 4, and the antireflection layer was bonded to the polarizing plate (essentially an easy-adhesive layer) via the first adhesive layer. Similarly, a second adhesive layer was formed on one side of the retardation film constituting the retardation layer obtained in Production Example 3, and the retardation film was bonded to the polarizing plate (essentially an easy-adhesive layer) through the second adhesive layer. Next, irradiate visible light with an active energy ray irradiation device to harden the first and second adhesive layers, and then dry them with hot air at 70°C for 3 minutes to produce a circular polarizing plate with an antireflective layer. Also, an acrylic adhesive layer (23 μm) was provided on the surface of the retardation layer of the circular polarizing plate with antireflection layer (opposite to the polarizer). Here, the polarizing plate and the retardation layer (retardation film) were bonded so that the absorption axis of the polarizer and the slow axis of the retardation film formed an angle of 45°. The obtained circular polarizing plate with an antireflection layer was subjected to the evaluations in (1) to (4) above. The results are shown in Table 1.

[Table 1]

[evaluate] It can be seen from Table 1 that the circular polarizing plate with anti-reflection layer according to the embodiment of the present invention can realize a bright image display device with suppressed display unevenness under high temperature and high humidity environment. Industrial availability

The circular polarizing plate with an antireflection layer of the present invention can be suitably used in image display devices (usually liquid crystal display devices, organic EL display devices).

10: polarizer 11: Polarizer 12: The first protective layer 13: The second protective layer 21: The first adhesive layer 22: The second adhesive layer 30: Anti-reflection layer 40: Retardation layer 50: Adhesive layer 100: circular polarizing plate with anti-reflection layer

Fig. 1 is a schematic cross-sectional view of a circular polarizing plate with an antireflection layer according to an embodiment of the present invention.

10: polarizer

11: Polarizer

12: The first protective layer

21: The first adhesive layer

22: The second adhesive layer

30: Anti-reflection layer

40: Retardation layer

50: Adhesive layer

100: circular polarizing plate with anti-reflection layer

Claims (7)

A circular polarizing plate with an anti-reflection layer, comprising: a polarizing plate including a polarizer; an anti-reflection layer disposed on one side of the polarizing plate; and a retardation layer disposed on the other side of the polarizing plate; and the transmittance of the circular polarizing plate with an anti-reflection layer is above 45.5%, and its reflectance after a 500-hour heating and humidifying test at 60°C and 90% RH is below 2.5%. A circular polarizing plate with an antireflection layer as claimed in Claim 1, wherein the polarizer is attached to the protective layer on the antireflection layer side through a first adhesive layer, and the polarizer and the retardation layer are attached through a second adhesive layer; at least one of the first adhesive layer and the adhesive of the second adhesive layer is composed of an active energy ray-curable adhesive composition. When the total amount of the composition is set to 100% by weight, the active energy ray-curable adhesive composition contains: SP value 29.0 (MJ /m³)^1/2Above and 32.0(MJ/m³)^1/2The following active energy ray-curable compound (A) 0.0% by weight to 4.0% by weight; SP value 18.0 (MJ/m³)^1/2Above and less than 21.0(MJ/m³)^1/2The active energy ray-curable compound (B) is 5.0% by weight to 98.0% by weight; and the SP value is 21.0 (MJ/m³)^1/2Above and 26.0(MJ/m³)^1/2The following active energy ray-curable compound (C) is 5.0% by weight to 98.0% by weight. A circular polarizing plate with an anti-reflection layer according to claim 1 or 2, wherein the reflectance of the anti-reflection layer is 1.5% or less. Such as the circular polarizing plate with an anti-reflection layer of claim 1 or 2, wherein the Re(550) of the retardation layer is 100nm~200nm, and the angle formed by the slow axis of the retardation layer and the absorption axis of the polarizer is 40°~50° or 130°~140°. Circular polarizing plate with an anti-reflection layer as claimed in claim 1 or 2, wherein the aforementioned retardation layer is composed of a stretched film of a resin film, and the Re(450)/Re(550) of the retardation layer is 0.80~1.03: Here, Re(450) and Re(550) are the in-plane retardation measured with light of wavelength 450nm and 550nm at 23°C, respectively. An image display device is equipped with a circular polarizing plate with an anti-reflection layer according to any one of Claims 1 to 5 on the viewing side, the aforementioned anti-reflection layer of the circular polarizing plate with an anti-reflection layer is arranged on the viewing side, and the reflectance of the image display device is 40% or less. The image display device according to Claim 6 is an organic electroluminescence display device.

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