Polarizing plate with phase difference layer and adhesive layer, and image display device using the same

Abstract

The present application provides a polarizing plate with a retardation layer and an adhesive layer, which can realize an image display device in which retardation unevenness is suppressed and color unevenness is suppressed in a high-temperature environment. The polarizing plate with a retardation layer and an adhesive layer of the present application has: a polarizing plate including a polarizer; a retardation layer attached to the polarizing plate via a first adhesive layer; and a second adhesive layer provided as an outermost layer on the side of the retardation layer opposite the polarizing plate. The retardation layer is composed of a stretched film of a resin film, satisfies the relationship Re(450) < Re(550), and has a slow-axis direction shrinkage rate of 4% or less when heated at 80°C to 125°C for 180 minutes. The paste shift amount after a heating test at 85°C and 500 hours of the first adhesive layer is 300 μm or more.

Description

Technical Field

[0001] The present invention relates to a polarizing plate having a phase difference layer and an adhesive layer, and an image display device using the polarizing plate having the phase difference layer and the adhesive layer. Background Art

[0002] In recent years, image display devices represented by liquid crystal display devices and electroluminescent (EL) display devices (such as organic EL display devices and inorganic EL display devices) have been rapidly popularized. Representative image display devices use a polarizing plate and a retardation plate. In actual use, a polarizing plate with a phase difference layer formed by integrating a polarizing plate and a retardation plate is widely used (for example, Patent Document 1). However, the polarizing plate with a phase difference layer generates uneven phase difference in a high-temperature environment. As a result, there is a case where color unevenness occurs in the image display device in a high-temperature environment.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent No. 3325560 Summary of the Invention

[0006] Technical Problem to be Solved by the Invention

[0007] The present invention is made to solve the above-described prior art problems, and its main object is to provide a polarizing plate having a phase difference layer and an adhesive layer, which can realize an image display device in which uneven phase difference is suppressed in a high-temperature environment and color unevenness is suppressed in a high-temperature environment.

[0008] Means for Solving the Technical Problem

[0009] The polarizing plate having a phase difference layer and an adhesive layer according to an embodiment of the present invention has: a polarizing plate including a polarizer; a phase difference layer bonded to the polarizing plate via a first adhesive layer; and a second adhesive layer provided as an outermost layer on a side of the phase difference layer opposite to the polarizing plate. The phase difference layer is formed of a stretched film of a resin film, satisfies the relationship of Re(450) < Re(550), and has a shrinkage rate in the slow axis direction of 4% or less when heated at 80°C to 125°C for 180 minutes. The paste offset amount of the first adhesive layer after a heating test at 85°C for 500 hours is 300 μm or more. Here, Re(450) and Re(?)550) are the in-plane phase differences measured using light with wavelengths of 450 nm and 550 nm at 23°C, respectively.

[0010] In one embodiment, the Re(550) of the phase difference layer is 100nm to 200nm, and the angle between the slow axis of the phase difference layer and the absorption axis of the polarizer is 40° to 50° or 130° to 140°.

[0011] In one embodiment, the thickness of the phase retardation layer is 15 μm to 60 μm.

[0012] In one embodiment, the stretch film constituting the phase difference layer is a film obtained by heat treatment at a temperature of 105°C or higher for 2 minutes or more.

[0013] In one embodiment, the polarizer with the phase retardation layer and the adhesive layer further has another phase retardation layer between the phase retardation layer and the second adhesive layer, which has a refractive index characteristic showing the relationship nz>nx=ny.

[0014] In one embodiment, the phase difference layer comprises: a resin having positive refractive index anisotropy, comprising at least one bonding group selected from carbonate bonds and ester bonds and at least one structural unit selected from the structural units shown in general formula (1) and general formula (2) below; and an acrylic resin having an content of 0.5% to 2.0% by mass, wherein the acrylic resin contains more than 70% by mass of structural units derived from methyl methacrylate, and has a weight-average molecular weight Mw of 10,000 to 200,000.

[0015] [Chemical structural formula 1]

[0016]

[0017] [Chemical structural formula 2]

[0018]

[0019] In general formulas (1) and (2), R 1 ~R 3 R are, independently, alkylene groups having 1 to 4 carbon atoms, either directly bonded, substituted, or unsubstituted. 4 ~R 9 Each of the following is independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 4 to 10 carbon atoms, a substituted or unsubstituted acyl group having 1 to 10 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms, a substituted or unsubstituted aryloxy group having 1 to 10 carbon atoms, a substituted or unsubstituted amino group, a substituted or unsubstituted vinyl group having 1 to 10 carbon atoms, a substituted or unsubstituted ethynyl group having 1 to 10 carbon atoms, a sulfur atom having a substituent, a silicon atom having a substituent, a halogen atom, a nitro group, or a cyano group; wherein, R 4 ~R 9They can be the same or different, R 4 ~R 9 At least two adjacent groups can also bond together to form a ring.

[0020] According to another aspect of the present invention, an image display device is provided. This image display device includes the aforementioned polarizer with a phase retardation layer and an adhesive layer.

[0021] Invention Effects

[0022] According to an embodiment of the present invention, by optimizing the combination of the paste offset of the adhesive layer between the polarizer and the retardation layer and the heating shrinkage rate of the retardation layer in the slow axis direction, a polarizer with a retardation layer and an adhesive layer can be realized that suppresses phase difference unevenness under high temperature conditions. As a result, an image display device that suppresses color unevenness under high temperature conditions can be realized. Attached Figure Description

[0023] Figure 1 This is a schematic cross-sectional view of a polarizer with a phase retardation layer and an adhesive layer according to one embodiment of the present invention. Detailed Implementation

[0024] The following describes representative embodiments of the present invention, but the present invention is not limited to these embodiments.

[0025] (Definitions of terms and symbols)

[0026] The terms and symbols used in this manual are defined as follows.

[0027] (1) Refractive index (nx, ny, nz)

[0028] “nx” is the refractive index in the direction where the refractive index is greatest (i.e., the slow axis direction), “ny” is the refractive index in the direction orthogonal to the slow axis (i.e., the fast axis direction), and “nz” is the refractive index in the thickness direction.

[0029] (2) In-plane phase difference (Re)

[0030] “Re(λ)” represents the in-plane phase difference of the film measured at 23°C using light with a wavelength of λ nm. For example, “Re(450)” represents the in-plane phase difference of the film measured at 23°C using light with a wavelength of 450 nm. Re(λ) is calculated using the formula: Re = (nx - ny) × d when the thickness of the film is set to d (nm).

[0031] (3) Phase difference (Rth) in the thickness direction

[0032] “Rth(λ)” represents the phase difference in the thickness direction of the film measured at 23°C using light with a wavelength of λnm. For example, “Rth(450)” represents the phase difference in the thickness direction of the film measured at 23°C using light with a wavelength of 450nm. Rth(λ) is calculated using the formula: Rth=(nx-nz)×d when the film thickness is set to d (nm).

[0033] (4) Nz coefficient

[0034] The Nz coefficient is obtained by Nz = Rth / Re.

[0035] (5) Angle

[0036] In this instruction manual, when referring to angles, unless otherwise specified, the angles include both clockwise and counterclockwise angles.

[0037] A. Overall structure of a polarizer with a phase retardation layer and an adhesive layer

[0038] Figure 1 This is a schematic cross-sectional view of a polarizer with a phase retardation layer and an adhesive layer according to an embodiment of the present invention. The illustrated polarizer 100 with a phase retardation layer and an adhesive layer includes: a polarizer 10; a phase retardation layer 30 bonded to the polarizer 10 via a first adhesive layer 20; and a second adhesive layer 40 disposed as the outermost layer on the side of the phase retardation layer 30 opposite to the polarizer 10. The polarizer with the phase retardation layer and adhesive layer can be attached to an image display unit via the second adhesive layer 40. The polarizer 10 includes a polarizer 11, a first protective layer 12 disposed on one side of the polarizer 11, and a second protective layer 13 disposed on the other side of the polarizer 11. Depending on the purpose, one of the first protective layer 12 and the second protective layer 13 may be omitted. For example, the phase retardation layer 30 may also function as a protective layer for the polarizer 11, thus the second protective layer 13 may be omitted. The angle between the slow axis of the phase difference layer 30 and the absorption axis of the polarizer 11 is preferably 40° to 50°, more preferably 42° to 48°, even more preferably 44° to 46°, particularly preferably about 45°, or preferably 130° to 140°, more preferably 132° to 138°, even more preferably 134° to 136°, particularly preferably about 135°.

[0039] The retardation layer 30 is composed of a stretched film of a resin film, satisfies the relationship of Re(450) < Re(550), and has a shrinkage rate in the slow axis direction of 4% or less when heated at 80°C to 125°C for 180 minutes. Re(550) of the retardation layer 30 is typically 100 nm to 200 nm. The paste offset amount after the heating test at 85°C for 500 hours of the first adhesive layer 20 is 300 μm or more. Details of each layer of the polarizing plate including the retardation layer and the adhesive layer will be described later.

[0040] In one embodiment, the polarizing plate with a retardation layer and an adhesive layer may further have another retardation layer (not shown) between the retardation layer 30 and the second adhesive layer 40. Regarding another retardation layer, typically, the refractive index characteristics show the relationship of nz > nx = ny. By providing such another retardation layer, reflection in the oblique direction can be well prevented, and a wide viewing angle of the antireflection function can be achieved.

[0041] In one embodiment, the polarizing plate with a retardation layer and an adhesive layer may further have a conductive layer or an isotropic substrate with a conductive layer (not shown). When the conductive layer or the isotropic substrate with a conductive layer is provided, the polarizing plate with a retardation layer and an adhesive layer can be applied to a so-called internal touch panel type input display device in which a touch sensor is assembled between an image display unit (such as an organic EL unit) and the polarizing plate. The conductive layer or the isotropic substrate with a conductive layer is typically provided between the retardation layer 30 and the second adhesive layer 40. When another retardation layer is provided, another retardation layer and the conductive layer or the isotropic substrate with a conductive layer are typically provided in sequence starting from the side of the retardation layer 30.

[0042] The polarizing plate with a retardation layer and an adhesive layer may also have yet another retardation layer (not shown). Yet another retardation layer can be provided in combination with another retardation layer or alone (i.e., without providing another retardation layer). The optical characteristics (such as refractive index characteristics, in-plane retardation, Nz coefficient, photoelastic coefficient), thickness, arrangement position, etc. of yet another retardation layer can be appropriately set according to the purpose.

[0043] The polarizing plate with a retardation layer and an adhesive layer can be in a single sheet form or in a long strip form. In this specification, the so-called "long strip form" means an elongated shape that is long enough relative to the width, for example, including an elongated shape in which the length is 10 times or more, preferably 20 times or more, relative to the width. The polarizing plate with a retardation layer and an adhesive layer in a long strip form can be wound into a roll.

[0044] In practical applications, it is preferable to temporarily adhere the release film to the surface of the second adhesive layer 40 until the polarizer with the phase retardation layer and adhesive layer is ready for use. By temporarily adhering the release film, the second adhesive layer can be protected, and a roll of polarizer with the phase retardation layer and adhesive layer can be formed.

[0045] The following describes the constituent elements of a polarizer with a phase retardation layer and an adhesive layer.

[0046] B. Polarizer

[0047] As the polarizer 11, any suitable polarizer can be used. For example, the resin film forming the polarizer can be a single-layer resin film or a laminate of two or more layers.

[0048] Specific examples of polarizers composed of single-layer resin films include polarizers obtained by dyeing and stretching hydrophilic polymer films such as polyvinyl alcohol (PVA) films, partially formalized PVA films, and partially saponified ethylene-vinyl acetate copolymer films with dichroic substances such as iodine or dichroic dyes; and polyene-based oriented films such as dehydrated PVA products or dehydrochlorinated polyvinyl chloride products. Due to their excellent optical properties, polarizers obtained by dyeing PVA films with iodine and then uniaxially stretching them are preferred.

[0049] The dyeing process using iodine described above is performed, for example, by immersing the PVA membrane in an aqueous iodine solution. The stretching ratio for the uniaxial stretching is preferably 3 to 7 times. Stretching can be performed after dyeing or simultaneously with dyeing. Alternatively, dyeing can be performed after stretching. Depending on the requirements, the PVA membrane may undergo swelling treatment, cross-linking treatment, washing treatment, drying treatment, etc. For example, by immersing the PVA membrane in water for washing before dyeing, not only can stains or anti-blocking agents on the surface of the PVA membrane be washed away, but the PVA membrane can also swell to prevent uneven dyeing.

[0050] As a specific example of a polarizer obtained using a laminate, examples include polarizers obtained using a laminate of a resin substrate and a PVA-based resin layer (PVA-based resin film) laminated on the resin substrate, or a laminate of a resin substrate and a PVA-based resin layer coated on the resin substrate. A polarizer obtained using a laminate of a resin substrate and a PVA-based resin layer coated on the resin substrate can be manufactured, for example, by coating a PVA-based resin solution onto a resin substrate, drying it to form a PVA-based resin layer on the resin substrate, thereby obtaining a laminate of the resin substrate and the PVA-based resin layer; and stretching and dyeing the laminate to form a polarizer from the PVA-based resin layer. In this embodiment, stretching typically includes immersing the laminate in an aqueous boric acid solution and then stretching it. Furthermore, stretching may, as needed, further include air stretching of the laminate at a high temperature (e.g., above 95°C) before stretching in the aqueous boric acid solution. The resulting resin substrate / polarizer laminate can be used directly (i.e., the resin substrate can be used as a protective layer for the polarizer), or the resin substrate can be peeled off from the resin substrate / polarizer laminate, and any suitable protective layer can be laminated on the peeled surface according to the purpose. Detailed descriptions of the manufacturing method of this polarizer are described, for example, in Japanese Patent Application Publication No. 2012-73580 and Japanese Patent No. 6470455. The descriptions in these patent documents are incorporated herein by reference.

[0051] The polarizer is preferably made of a single-layer resin film. With this configuration, a polarizer with a phase difference layer and an adhesive layer can be obtained by optimizing the synergistic effect with the first adhesive layer and the second adhesive layer, thereby suppressing phase difference unevenness under high temperature conditions.

[0052] The thickness of the polarizer is preferably 15 μm or less, more preferably 1 μm to 12 μm, and even more preferably 3 μm to 12 μm. If the thickness of the polarizer is within this range, curling during heating can be well suppressed, and good appearance durability during heating can be obtained.

[0053] The polarizer preferably exhibits absorption dichroism at any wavelength from 380 nm to 780 nm. The transmittance of the polarizer is, for example, 41.5% to 46.0%, preferably 43.0% to 46.0%, more preferably 44.5% to 46.0%. The polarization degree of the polarizer is preferably 97.0% or more, more preferably 99.0% or more, and even more preferably 99.9% or more.

[0054] C. Protective layer

[0055] The first protective layer 12 and the second protective layer 13 are each formed of any suitable film that can be used as a protective layer for a polarizer. Specific examples of materials that form the main component of the film include: cellulose resins such as triacetyl cellulose (TAC); or transparent resins such as polyester, polyvinyl alcohol, polycarbonate, polyamide, polyimide, polyethersulfone, polysulfone, polystyrene, polynorbornene, polyolefin, (meth)acrylate, and acetate. Additionally, thermosetting or UV-curing resins such as (meth)acrylate, urethane, (meth)acrylate urethane, epoxy, and silicone resins can also be used. Furthermore, glassy polymers such as siloxane polymers can also be used. Additionally, polymer films described in Japanese Patent Application Publication No. 2001-343529 (WO01 / 37007) can also be used. As the material for this membrane, for example, a resin composition containing a thermoplastic resin having substituted or unsubstituted imide groups on the side chains and a thermoplastic resin having substituted or unsubstituted phenyl and nitrile groups on the side chains can be used. Examples include resin compositions having alternating copolymers formed from isobutylene and N-methylmaleimide and acrylonitrile-styrene copolymers. The polymer membrane can be, for example, an extruded product of the above-mentioned resin composition.

[0056] A polarizer with a phase retardation layer and an adhesive layer is typically disposed on the viewable side of an image display device, as described below, and a first protective layer 12 is typically disposed on this viewable side. Therefore, the first protective layer 12 can be subjected to surface treatments such as hard coating, anti-reflective treatment, anti-sticking treatment, and anti-glare treatment, as needed. Furthermore / or, the first protective layer 12 can be treated to improve visibility when viewed through polarized sunglasses (typically by imparting (ellipsoidal) polarization or ultra-high phase retardation). By implementing such treatment, excellent visibility can be achieved even when viewing the display image through polarized lenses such as polarized sunglasses. Therefore, a polarizer with a phase retardation layer and an adhesive layer is also preferably used in image display devices that can be used outdoors.

[0057] The thickness of the first protective layer is typically 300 μm or less, preferably 100 μm or less, more preferably 5 μm to 80 μm, and even more preferably 10 μm to 60 μm. Furthermore, when a surface treatment is performed, the thickness of the outer protective layer includes the thickness of the surface treatment layer.

[0058] In one embodiment, the second protective layer 13 is preferably optically isotropic. In this specification, "optically isotropic" means that the in-plane phase difference Re(550) is 0 nm to 10 nm, and the phase difference Rth(550) in the thickness direction is -10 nm to +10 nm.

[0059] C. Phase difference layer

[0060] C-1. Characteristics of the retardation layer

[0061] The in-plane retardation Re(550) of the retardation layer is 100 nm to 200 nm as described above, preferably 110 nm to 180 nm, more preferably 120 nm to 160 nm, and further preferably 130 nm to 150 nm. That is, the retardation layer can function as a so-called λ / 4 plate.

[0062] The retardation layer satisfies the relationship of Re(450) < Re(550) as described above, and preferably further satisfies the relationship of Re(550) < Re(650). That is, the retardation layer shows an inverse-dispersion wavelength dependence in which the retardation value increases according to the wavelength of the measurement light. The Re(450) / Re(550) of the retardation film is, for example, more than 0.5 and less than 1.0, preferably 0.7 to 0.95, more preferably 0.75 to 0.92, and further preferably 0.8 to 0.9. The Re(650) / Re(550) is preferably 1.0 or more and less than 1.15, more preferably 1.03 to 1.1.

[0063] The retardation layer has an in-plane retardation as described above, and thus has the relationship of nx > ny. As long as the retardation layer has the relationship of nx > ny, it shows any appropriate refractive index characteristics. The refractive index characteristics of the retardation layer typically show the relationship of nx > ny ≥ nz. In addition, in this case, "ny = nz" includes not only the case where ny and nz are exactly equal but also the case where they are substantially equal. Therefore, within the range that does not impair the effects of the present invention, there may be a case where ny < nz. The Nz coefficient of the retardation layer is preferably 0.9 to 2.0, more preferably 0.9 to 1.5, and further preferably 0.9 to 1.2. By satisfying such a relationship, when a polarizing plate with a retardation layer and an adhesive layer is used in an image display device, a very excellent reflected hue can be achieved.

[0064] The thickness of the retardation layer can be set in such a way that it can function most appropriately as a λ / 4 plate. In other words, the thickness can be set in such a way that the desired in-plane retardation can be obtained. Specifically, the thickness is preferably 15 μm to 60 μm, further preferably 20 μm to 55 μm, and most preferably 20 μm to 45 μm. In the embodiment of the present invention, the thickness of the retardation layer can be significantly reduced compared to a λ / 4 plate composed of a conventional resin film.

[0065] In the embodiment of the present invention, the shrinkage rate of the slow axis direction when the retardation layer is heated at 80°C to 125°C for 180 minutes is 4% or less as described above, preferably 3.5% or less, and more preferably 3% or less. The smaller the shrinkage rate, the more preferable, and the lower limit can be, for example, 0.5%.

[0066] The elongation at break of the stretched film constituting the retardation layer is preferably 200% or more, more preferably 210% or more, even more preferably 220% or more, and particularly preferably 245% or more. The upper limit of the elongation at break can be, for example, 500%. In addition to its excellent phase difference performance, the stretched film used in the retardation layer of the embodiments of the present invention also exhibits excellent scalability, thus enabling the achievement of the desired in-plane phase difference with a very thin thickness through their synergistic effect. Furthermore, in this specification, the term "elongation at break" refers to the elongation at which the film breaks during uniaxial stretching at a fixed end at a specified stretching temperature (e.g., Tg-2°C).

[0067] Regarding the retardation layer, the absolute value of its photoelastic coefficient is preferably 20 × 10⁻⁶. -12 (m 2 / N) or less, more preferably 1.0×10 -12 (m 2 / N)~15×10 -12 (m 2 / N), further preferably 2.0×10 -12 (m 2 / N)~12×10 -12 (m 2 / N). If the absolute value of the photoelastic coefficient is within this range, then when a polarizer with a phase retardation layer and an adhesive layer is used in an image display device, display unevenness can be suppressed.

[0068] C-2. Constituent materials of the retardation layer

[0069] The retardation layer typically contains a resin comprising at least one bonding group selected from carbonate bonds and ester bonds. In other words, the retardation layer contains a polycarbonate resin, a polyester resin, or a polyester-carbonate resin (hereinafter sometimes collectively referred to as polycarbonate resin, etc.). The polycarbonate resin, etc., comprises at least one structural unit selected from the structural units shown in the above general formula (1) and / or the structural units shown in the above general formula (2). These structural units are structural units derived from divalent oligofluorene, hereinafter sometimes referred to as oligofluorene structural units. Such polycarbonate resin, etc., has positive refractive index anisotropy.

[0070] Regarding the retardation layer, it is representative that it further contains an acrylic resin. The content of the acrylic resin is 0.5% to 1.5% by mass. Furthermore, in this specification, the percentage or parts in the unit "mass" has the same meaning as the percentage or parts in the unit "weight".

[0071] C-2-1. Polycarbonate resins, etc.

[0072] <Oligomeric Fluorene Structural Unit>

[0073] The oligomeric fluorene structural unit is represented by the above general formula (1) or (2). In general formulas (1) and (2), R 1 ~R 3 R are, independently, alkylene groups having 1 to 4 carbon atoms, either directly bonded, substituted, or unsubstituted. 4 ~R 9 Each of the following is independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 4 to 10 carbon atoms, a substituted or unsubstituted acyl group having 1 to 10 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms, a substituted or unsubstituted aryloxy group having 1 to 10 carbon atoms, a substituted or unsubstituted amino group, a substituted or unsubstituted vinyl group having 1 to 10 carbon atoms, a substituted or unsubstituted ethynyl group having 1 to 10 carbon atoms, a sulfur atom having a substituent, a silicon atom having a substituent, a halogen atom, a nitro group, or a cyano group. Wherein, R 4 ~R 9 They can be the same or different, R 4 ~R 9 At least two adjacent groups can also bond together to form a ring.

[0074] The content of oligofluorene structural units in polycarbonate resins and the like is preferably 1% to 40% by mass relative to the total resin content, more preferably 10% to 35% by mass, even more preferably 15% to 30% by mass, and particularly preferably 18% to 25% by mass. Excessive content of oligofluorene structural units raises concerns about problems such as an excessively high photoelasticity coefficient, insufficient reliability, and insufficient phase difference performance. Furthermore, due to the higher proportion of oligofluorene structural units in the resin, the range of molecular design narrows, making it difficult to improve the resin during modification. On the other hand, even if the desired inverse dispersion wavelength dependence is obtained with a very small amount of oligofluorene structural units, the optical properties will change sensitively with slight deviations in the content of the oligofluorene structural units, making it difficult to manufacture in a way that controls various properties within a certain range.

[0075] Details of the oligomeric fluorene structural units are described, for example, in International Publication No. 2015 / 159928. This publication is incorporated herein by reference.

[0076] <Other structural units>

[0077] Regarding polycarbonate resins, for example, they may contain other structural units besides oligofluorene structural units. In one embodiment, the other structural units are preferably derived from dihydroxy compounds or diester compounds. In order to exhibit the desired reverse dispersion wavelength properties, since it is necessary to introduce structural units with positive intrinsic birefringence and oligofluorene structural units with negative intrinsic birefringence into the polymer structure, dihydroxy compounds or diester compounds that serve as raw materials for the structural units with positive birefringence are further preferred as other monomers for copolymerization.

[0078] Examples of comonomers include: compounds that can incorporate structural units containing aromatic rings; and compounds that do not incorporate structural units containing aromatic rings, i.e., compounds composed of aliphatic structures.

[0079] The following are specific examples of the compounds composed of aliphatic structures. Dihydroxy compounds of straight-chain aliphatic hydrocarbons such as ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 1,5-heptanediol, 1,6-hexanediol, 1,9-nonanediol, 1,10-decanediol, and 1,12-dodecanediol; dihydroxy compounds of branched-chain aliphatic hydrocarbons such as neopentyl glycol and hexanediol; dihydroxy compounds of secondary and tertiary alcohols of alicyclic hydrocarbons such as 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,3-adamantanediol, hydrogenated bisphenol A, and 2,2,4,4-tetramethyl-1,3-cyclobutanediol; 1,2-cyclohexanediethanol, 1,3-cyclohexanediethanol, 1,4-cyclohexanediethanol, tricyclodecanediethanol, pentacyclopentadecanedimethanol, and 2,6-decahydronaphthalene. Dihydroxy compounds that are primary alcohols of alicyclic hydrocarbons, such as diethanol, 1,5-decahydronaphthalenediethanol, 2,3-decahydronaphthalenediethanol, 2,3-norbornanediethanol, 2,5-norbornanediethanol, 1,3-adamantanediethanol, and limonene; oxoalkylene glycols such as diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, and polypropylene glycol; dihydroxy compounds with cyclic ether structures such as isosorbide; dihydroxy compounds with cyclic acetal structures such as spirodiol and dioxanediol; alicyclic dicarboxylic acids such as 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid; and aliphatic dicarboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, octanoic acid, azelaic acid, and sebacic acid.

[0080] Specific examples of compounds incorporating the aforementioned aromatic ring structural unit are given below: 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(3-methyl-4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 2,2-bis(4-hydroxy-3,5-diethylphenyl)propane, 2,2-bis(4-hydroxy-(3-phenyl)phenyl)propane, 2,2-bis(4-hydroxy-(3,5-diphenyl)phenyl)propane, 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane, bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)propane. Ethane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)pentane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, bis(4-hydroxyphenyl)diphenylmethane, 1,1-bis(4-hydroxyphenyl)-2-ethylhexane, 1,1-bis(4-hydroxyphenyl)decane, bis(4-hydroxy-3-nitrophenyl)methane, 3,3-bis(4-hydroxyphenyl)pentane, 1,3-bis(2-(4-hydroxyphenyl)-2-propyl)benzene, 1,3-bis(2-(4-hydroxyphenyl)-2-propyl)benzene, 2,2-bis ... Aromatic bisphenol compounds such as propylbenzene, 2,2-bis(4-hydroxyphenyl)hexafluoropropane, 1,1-bis(4-hydroxyphenyl)cyclohexane, bis(4-hydroxyphenyl)sulfone, 2,4'-dihydroxydiphenylsulfone, bis(4-hydroxyphenyl)sulfide, bis(4-hydroxy-3-methylphenyl)sulfide, bis(4-hydroxyphenyl)disulfide, 4,4'-dihydroxydiphenyl ether, and 4,4'-dihydroxy-3,3'-dichlorodiphenyl ether; 2,2-bis(4-(2-hydroxyethoxy)phenyl)propane, 2,2-bis(4-(2-hydroxyphenyl)cyclohexane, etc. Dihydroxy compounds containing an ether group bonded to an aromatic group, such as 1,3-bis(2-hydroxyethoxy)benzene, 4,4'-bis(2-hydroxyethoxy)biphenyl, and bis(4-(2-hydroxyethoxy)phenyl)sulfone; aromatic dicarboxylic acids such as terephthalic acid, phthalic acid, isophthalic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-diphenyl ether dicarboxylic acid, 4,4'-benzophenone dicarboxylic acid, 4,4'-diphenoxyethane dicarboxylic acid, 4,4'-diphenyl sulfone dicarboxylic acid, and 2,6-naphthalene dicarboxylic acid.

[0081] In addition, the aliphatic and aromatic dicarboxylic acids mentioned above can be used as raw materials for the polyester carbonate, but depending on the manufacturing method, dicarboxylic acid esters such as methyl esters and phenyl esters or dicarboxylic acid derivatives such as dicarboxylic acid halides can also be used as raw materials.

[0082] As comonomers, dihydroxy compounds with fluorene rings, such as 9,9-bis(4-(2-hydroxyethoxy)phenyl)fluorene, 9,9-bis(4-hydroxyphenyl)fluorene, and 9,9-bis(4-hydroxy-3-methylphenyl)fluorene, or dicarboxylic acid compounds with fluorene rings, which are known in the past as compounds containing structural units with negative birefringence, can also be used in combination with oligomeric fluorene compounds.

[0083] Regarding the resin used in this invention, the structural unit that can be introduced through the compound having an alicyclic structure preferably contains the structural unit shown in the following formula (3) as a copolymer component.

[0084] [Chemical structural formula 3]

[0085]

[0086] Spirodiol can be used as a dihydroxy compound that can be incorporated into the structural unit of formula (3).

[0087] In the resin used in this invention, the structural unit shown in formula (3) preferably contains 5% by mass or more and 90% by mass or less. The upper limit is further preferably 70% by mass or less, and particularly preferably 50% by mass or less. The lower limit is further preferably 10% by mass or more, more preferably 20% by mass or more, and particularly preferably 25% by mass or more. If the content of the structural unit shown in formula (3) is above the lower limit, sufficient mechanical properties or heat resistance and a low photoelastic coefficient can be obtained. Furthermore, the compatibility with acrylic resins is improved, and the transparency of the resulting resin composition can be further improved. In addition, the polymerization reaction of spirodiol is relatively slow, so by suppressing the content to below the upper limit, the polymerization reaction is easily controlled.

[0088] The resin used in this invention preferably further contains the structural unit shown in the following formula (4) as a copolymer component.

[0089] [Chemical structural formula 4]

[0090]

[0091] Examples of dihydroxy compounds that can incorporate the structural unit shown in formula (4) include isosorbide (ISB), isomannitol, and isoidolitol, which are stereoisomers. They can be used individually or in combination of two or more.

[0092] In the resin used in this invention, the structural unit shown in formula (4) preferably contains 5% by mass or more and 90% by mass or less. The upper limit is further preferably 70% by mass or less, and particularly preferably 50% by mass or less. The lower limit is further preferably 10% by mass or more, and particularly preferably 15% by mass or more. If the content of the structural unit shown in formula (4) is above the lower limit, sufficient mechanical properties or heat resistance and a low photoelasticity coefficient can be obtained. In addition, the structural unit shown in formula (4) has the characteristic of high water absorption, so if the content of the structural unit shown in formula (4) is below the upper limit, the dimensional changes of the molded body caused by water absorption can be suppressed within an acceptable range.

[0093] The resin used in this invention may further contain other structural units. Furthermore, these structural units are sometimes referred to as "other structural units." As monomers containing other structural units, 1,4-cyclohexanediethanol, tricyclodecanediethanol, and 1,4-cyclohexanedicarboxylic acid (and its derivatives) are more preferred, with 1,4-cyclohexanediethanol and tricyclodecanediethanol being particularly preferred. Resins containing structural units derived from these monomers exhibit an excellent balance of optical properties, heat resistance, mechanical properties, etc. Additionally, since diester compounds have low polymerization reactivity, from the viewpoint of improving reaction efficiency, it is preferable not to use diester compounds other than those containing oligomeric fluorene structural units.

[0094] The glass transition temperature (Tg) of the resin used in this invention is preferably 110°C or higher and 160°C or lower. The upper limit is further preferably 155°C or lower, more preferably 150°C or lower, and particularly preferably 145°C or lower. The lower limit is further preferably 120°C or higher, and particularly preferably 130°C or higher. If the glass transition temperature is outside the above range, there is a tendency for the heat resistance to deteriorate, which may cause dimensional changes after film formation, or reduce the reliability of the quality under the conditions of phase difference film use. On the other hand, if the glass transition temperature is too high, uneven film thickness may occur during film formation, or the film may become brittle and have poor tensile strength, and the transparency of the film may also be compromised.

[0095] Detailed information regarding the composition and manufacturing methods of polycarbonate resins, etc., is described, for example, in International Publication No. 2015 / 159928 (mentioned above). This description is incorporated herein by reference.

[0096] C-2-2. Acrylic resin

[0097] As an acrylic resin, an acrylic resin that is a thermoplastic resin is used. Examples of monomers that form the structural units of an acrylic resin include: methyl methacrylate, methacrylic acid, methyl acrylate, acrylic acid, benzyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, stearyl (meth)acrylate, glycidyl (meth)acrylate, hydroxypropyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, norbornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentyl (meth)acrylate, and so on. Dicyclopentenoxyethyl acrylate, tetrahydrofurfuryl acrylate, acryloyl(meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-(meth)acryloyloxyethyl succinate, 2-(meth)acryloyloxyethyl maleate, 2-(meth)acryloyloxyethyl phthalate, 2-(meth)acryloyloxyethyl hexahydrophthalate, pentamethylpiperidinyl (meth)acrylate, tetramethylpiperidinyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, cyclopentyl methacrylate, cyclopentyl acrylate, cyclohexyl methacrylate, cyclohexyl acrylate, cycloheptyl methacrylate, cycloheptyl acrylate, cyclooctyl methacrylate, cyclooctyl acrylate, cyclododecyl methacrylate, cyclododecyl acrylate. These can be used alone or in combination of two or more monomers. Examples of using two or more monomers in combination include copolymerization of two or more monomers, blending of two or more homopolymers of one monomer, and combinations thereof. Furthermore, other monomers that can copolymerize with these acrylic monomers (such as olefin monomers and vinyl monomers) can also be used.

[0098] The acrylic resin contains structural units derived from methyl methacrylate. The content of the methyl methacrylate-derived structural units in the acrylic resin is preferably 70% by mass or more and 100% by mass or less. More preferably, it is 80% by mass or more, further preferably 90% by mass or more, and particularly preferably 95% by mass or more. Within this range, excellent compatibility with the polycarbonate-based resin of the present invention can be obtained. As structural units other than methyl methacrylate, methyl acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, and styrene are preferably used. Copolymerizing methyl acrylate improves thermal stability. By using phenyl (meth)acrylate, benzyl (meth)acrylate, and styrene, the refractive index of the acrylic resin can be adjusted; therefore, by adjusting the refractive index of the combined resin, the transparency of the obtained resin composition can be improved. Using such an acrylic resin, a reverse dispersion phase difference film with excellent spreadability and phase difference performance and low haze can be obtained.

[0099] The weight-average molecular weight (Mw) of the acrylic resin is 10,000 or more and 200,000 or less. The lower limit is preferably 30,000 or more, particularly preferably 50,000 or more. The upper limit is preferably 180,000 or less, particularly preferably 150,000 or less. If the molecular weight is within this range, compatibility with polycarbonate resins can be obtained, thereby improving the transparency of the final retardation film (retardation layer) and significantly improving its stretchability during stretching. Furthermore, the aforementioned weight-average molecular weight is the molecular weight converted from polystyrene measured using GPC (Gel Permeation Chromatography). Additionally, from a compatibility point of view, the acrylic resin is preferably substantially free of branched structures. The absence of branched structures can be confirmed by the unimodality of the GPC curve of the acrylic resin.

[0100] C-2-3. Blending of polycarbonate resins with acrylic resins

[0101] A method for manufacturing a retardation film (retardation layer) by blending polycarbonate resins and acrylic resins (the manufacturing method is described below in section C-3). The polycarbonate resins and acrylic resins are preferably blended in a molten state. A representative method for blending in a molten state is melt mixing using an extruder. The mixing temperature (molten resin temperature) is preferably 200°C to 280°C, more preferably 220°C to 270°C, and even more preferably 230°C to 260°C. If the mixing temperature is within this range, thermal decomposition can be suppressed, and granules of a resin composition uniformly blended with the two resins can be obtained. If the molten resin temperature in the extruder exceeds 280°C, resin coloring and / or thermal decomposition may occur. On the other hand, if the molten resin temperature in the extruder is below 200°C, the resin viscosity may be too high, resulting in excessive load on the extruder, or the resin may not be sufficiently melted. Furthermore, any suitable configuration can be used for the extruder, screw, etc. To obtain the transparency of the resin suitable for optical film applications, a biaxial extruder is preferred. Furthermore, there are concerns that residual low-molecular-weight components in the resin or low-molecular-weight thermally decomposed components from the extrusion compounding may contaminate the cooling rollers or conveyor rollers during the film-forming or stretching processes. Therefore, to remove these components, an extruder equipped with a vacuum vent is preferred.

[0102] The content of acrylic resin in the resin composition (resulting in a phase retardation layer) is, as described above, 0.5% by mass or more and 2.0% by mass or less. The lower limit is more preferably 0.6% by mass or more. The upper limit is preferably 1.5% by mass or less, more preferably 1.0% by mass or less, further preferably 0.9% by mass or less, and particularly preferably 0.8% by mass or less. Thus, by blending acrylic resin into the polycarbonate resin at a very limited ratio, spreadability and phase retardation performance can be significantly increased. Furthermore, haze can be suppressed. This effect is not theoretically clear; it is an unexpectedly excellent effect obtained through repeated experiments. However, if the content of acrylic resin is too low, the above-mentioned effect may not be obtained. On the other hand, if the content of acrylic resin is too high, haze may increase. In addition, compared to the situation within the above range, spreadability and phase retardation performance are often insufficient or even reduced.

[0103] In order to modify mechanical properties and / or solvent resistance, the resin composition may be further blended with aromatic polycarbonate, aliphatic polycarbonate, aromatic polyester, aliphatic polyester, polyamide, polystyrene, polyolefin, acrylic acid, amorphous polyolefin, ABS (acrylonitrile-butadiene-styrene), AS (acrylonitrile-styrene), polylactic acid, polybutylene succinate and other synthetic resins, rubbers and combinations thereof.

[0104] The resin composition may further include additives. Specific examples of additives include heat stabilizers, antioxidants, catalyst deactivators, ultraviolet absorbers, light stabilizers, release agents, dyes / pigments, impact modifiers, antistatic agents, lubricants, plasticizers, compatibilizers, nucleating agents, flame retardants, inorganic fillers, and foaming agents. The type, quantity, combination, and content of additives included in the resin composition can be appropriately determined according to the purpose.

[0105] C-3. Methods for forming phase difference layers

[0106] The retardation layer can be obtained by forming a film from the resin composition described in section C-2 above, and then stretching the film. Any suitable forming process can be used as a method for forming the film from the resin composition. Specific examples include compression molding, transfer molding, injection molding, extrusion molding, blow molding, powder molding, FRP (Fiber Reinforced Plastics) molding, casting coating (e.g., casting), calendering, and hot pressing. Among these, extrusion molding or casting coating, which improves the smoothness of the obtained film and achieves good optical uniformity, is preferred. Casting coating raises concerns about problems caused by residual solvents; therefore, extrusion molding is particularly preferred. From the viewpoint of film productivity or ease of subsequent stretching, melt extrusion molding with a T-die is preferred. The forming conditions can be appropriately set according to the composition or type of resin used, the desired characteristics of the retardation layer, etc. In this way, a resin film containing polycarbonate resins and acrylic resins can be obtained.

[0107] The thickness of the resin film (unstretched film) can be set to any appropriate value according to the required thickness of the obtained retardation layer, the required optical properties, the stretching conditions described later, etc. Preferably, it is 50 μm to 300 μm.

[0108] The above stretching can be performed using any appropriate stretching method and conditions (e.g., stretching temperature, stretching ratio, stretching direction). Specifically, various stretching methods such as free-end stretching, fixed-end stretching, free-end contraction, and fixed-end contraction can be used individually, simultaneously, or sequentially. Regarding the stretching direction, it can also be performed in various directions or dimensions such as the length direction, width direction, thickness direction, and oblique direction.

[0109] By appropriately selecting the stretching method and stretching conditions described above, a phase difference layer with the aforementioned desired optical properties (e.g., refractive index characteristics, in-plane phase difference, Nz coefficient) can be obtained.

[0110] In one embodiment, the stretching temperature of the film is below the glass transition temperature (Tg) of the polycarbonate resin or the like. Generally, when stretching a film made of polycarbonate resin or the like, it is practically impossible to stretch below Tg because the film is in a glassy state. The resin film used according to the embodiment of the present invention, by incorporating a small amount of acrylic resin (typically polymethyl methacrylate), can achieve stretching below Tg without substantially altering the Tg of the polycarbonate resin or the like. Furthermore, although not theoretically clear, by stretching below Tg, a reverse dispersion phase difference film (phase difference layer) with excellent spreadability and phase difference performance and low haze can be achieved. Specifically, the stretching temperature is preferably Tg to Tg-10°C, more preferably Tg to Tg-8°C, and even more preferably Tg to Tg-5°C. Furthermore, if the film reaches, for example, around Tg+5°C, or around Tg+2°C, it can be appropriately stretched even at temperatures above Tg.

[0111] The stretched film obtained in the above manner is preferably subjected to a heat treatment at a temperature of 105°C or higher for at least 2 minutes. By performing the heat treatment, a phase difference layer having the desired shrinkage rate can be formed. The heating temperature is preferably 105°C to 140°C, more preferably 110°C to 130°C, and even more preferably 115°C to 125°C. The heating time is preferably 2 minutes to 150 minutes, more preferably 3 minutes to 120 minutes, and even more preferably 5 minutes to 60 minutes.

[0112] If necessary, the stretched film can also be subjected to a tempering treatment. This mitigates the stress generated by stretching, allowing the formation of a phase difference layer with the desired shrinkage rate. Any suitable conditions can be used as tempering treatment conditions. For example, the stretched film is shrunk along the stretching direction at a specified tempering temperature and a specified tempering rate (shrinkage rate). The tempering temperature is preferably 60°C to 150°C. The tempering rate is preferably 3% to 6%. Typically, the tempering treatment can be performed before the aforementioned heat treatment.

[0113] The phase retardation film constituting the phase retardation layer can be obtained in the manner described above.

[0114] D. First adhesive layer and second adhesive layer

[0115] D-1. Characteristics of the first adhesive layer and / or the second adhesive layer

[0116] Regarding the first adhesive layer 20, as described above, the paste offset after a heating test at 85°C and 500 hours is 300 μm or more, preferably 330 μm or more, more preferably 360 μm or more, even more preferably 390 μm or more, and particularly preferably 420 μm or more. The upper limit of the paste offset can be, for example, 600 μm. By using an adhesive with a large paste offset to bond the polarizer and the phase retardation layer, the synergistic effect of controlling the shrinkage rate of the phase retardation layer in the slow axis direction and controlling the creep value of the second adhesive layer (described later) can achieve a polarizer with a phase retardation layer and an adhesive layer that suppresses phase difference unevenness under high-temperature conditions. Furthermore, in this specification, "paste offset" refers to the length of the portion of the adhesive layer that overflows most from the end faces of the polarizer and the phase retardation layer after a heating test in the polarizer with the phase retardation layer and adhesive layer.

[0117] The creep value of the second adhesive layer 40 at 23°C is, for example, 5 μm or more, preferably 20 μm or more, more preferably 30 μm or more, even more preferably 60 μm or more, particularly preferably 100 μm or more, and especially preferably 120 μm or more. The upper limit of the creep value can be, for example, 300 μm. Thus, by using an adhesive with a high creep value to bond a polarizer with a phase retardation layer and an adhesive layer to an image display unit, the synergistic effect of controlling the shrinkage rate of the phase retardation layer in the slow axis direction and controlling the paste offset of the first adhesive layer can achieve an image display device that suppresses color unevenness at high temperatures. The creep value can be measured, for example, by attaching a test sample cut from the adhesive sheet to a support plate with a 10 mm × 10 mm joint surface. With the support plate to which the test sample is attached fixed, a load of 500 gf is applied vertically downwards. The offset from the support plate is measured after 1 second and 3600 seconds of applying the load, and denoted as Cr1 and Cr, respectively. 3600 . Will be composed of Cr1 and Cr 3600 The creep value is calculated using the following formula. Furthermore, the creep value in this specification is the value when the thickness of the adhesive layer is converted to 20 μm.

[0118] ΔCr=Cr 3600 -Cr1

[0119] The storage elastic modulus of the first adhesive layer and / or the second adhesive layer at 85°C is preferably 1.0 × 10⁻⁶. 4 Pa or higher, preferably 2.0 × 10 Pa. 4 Pa or higher, more preferably 5.0 × 10 Pa. 4 Pa or higher, more preferably 1.0 × 10 Pa. 5 Pa or higher. If the storage modulus of elasticity is within this range, the aforementioned required paste offset and / or creep value can be easily achieved. On the other hand, the storage modulus of elasticity is, for example, 3.0 × 10⁻⁶. 6 Below Pa.

[0120] The thickness of the first adhesive layer is preferably 2 μm to 50 μm, more preferably 3 μm to 40 μm. The thickness of the second adhesive layer is preferably 4 μm to 30 μm, more preferably 5 μm to 20 μm. If the thicknesses of the first and second adhesive layers are within these ranges, then through the synergistic effect with the effect of controlling the above-mentioned paste offset and creep value, a polarizer with a phase difference layer and an adhesive layer can be realized, which suppresses phase difference unevenness under high temperature conditions, and an image display device that suppresses color unevenness under high temperature conditions can also be realized.

[0121] D-2. Materials constituting the first adhesive layer and the second adhesive layer

[0122] Regarding the first and second adhesive layers, any suitable configuration can be used, provided that the first adhesive layer has the desired paste offset and the second adhesive layer has the desired creep value. The first and second adhesive layers can be composed of the same adhesive or of different adhesives. Hereinafter, the first and second adhesive layers will be described together as adhesive layers, and the constituent materials will be explained. The paste offset and / or creep value can be controlled by adjusting the composition of the adhesives constituting the adhesive layers (e.g., the type of base polymer (polarity, Tg, flexibility), molecular weight), and crosslinking structure (e.g., the type of crosslinking agent, the distance between crosslinking points (molecular weight between crosslinking points), and the crosslinking density).

[0123] D-2-1. Basic Polymer

[0124] The adhesive layer is typically formed from an adhesive composition containing a (meth)acrylate polymer, a urethane polymer, a silicone polymer, or a rubber polymer as a base polymer. When using a (meth)acrylate polymer as the base polymer, the adhesive layer is, for example, formed from an adhesive composition containing a (meth)acrylate polymer (A). The (meth)acrylate polymer (A) contains an alkyl (meth)acrylate as a main component.

[0125] <(Meth)Acrylic Polymer (A)>

[0126] The (meth)acrylic polymer (A) as described above contains alkyl (meth)acrylate as a main component. From the viewpoint of improving the adhesion of the adhesive layer, the alkyl (meth)acrylate preferably comprises 50% by weight or more of all monomer components forming the (meth)acrylic polymer (A), and the remaining monomers other than the alkyl (meth)acrylate can be arbitrarily determined. Furthermore, (meth)acrylate refers to acrylates and / or methacrylates.

[0127] Alkyl methacrylates, which form the main backbone of the (meth)acrylic polymer (A), can be alkyl methacrylates with linear or branched alkyl groups having 1 to 18 carbon atoms. Examples of alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, hexyl, cyclohexyl, heptyl, 2-ethylhexyl, isooctyl, nonyl, decyl, isodecyl, dodecyl, isomycinyl, lauryl, tridecyl, pentadecyl, hexadecyl, heptadecanyl, octadecyl, etc. Alkyl methacrylates can be used alone or in combination. The average number of carbon atoms in the alkyl group is preferably 3 to 10.

[0128] In (meth)acrylic polymer (A), in addition to alkyl (meth)acrylic acid esters as monomer components, comonomers such as carboxyl-containing monomers (a1) and hydroxyl-containing monomers (a2) may also be used as monomer components. Comonomers can be used alone or in combination.

[0129] A carboxyl-containing monomer (a1) is a compound whose structure contains a carboxyl group and polymerizable unsaturated double bonds such as (meth)acryloyl or vinyl groups. Examples of carboxyl-containing monomers include (meth)acrylic acid, carboxyethyl (meth)acrylic acid, carboxypentyl (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, and butenoic acid. Among these, acrylic acid is preferred from the viewpoints of copolymerization, price, and improved adhesive properties of the adhesive layer.

[0130] When using a carboxyl-containing monomer (a1) as a monomer component, the content of the carboxyl-containing monomer (a1) is generally more than 0.01% by weight and less than 10% by weight among all monomer components forming the (meth)acrylic polymer (A).

[0131] The hydroxyl-containing monomer (a2) is a compound whose structure contains a hydroxyl group and polymerizable unsaturated double bonds such as (meth)acryloyl group and vinyl group. Examples of hydroxyl-containing monomers include: 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylaurate (meth)acrylate, and other hydroxyalkyl (meth)acrylates; methyl (4-hydroxymethylcyclohexyl)acrylate, etc. From the viewpoint of improving the durability of the adhesive layer, 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are preferred, and 4-hydroxybutyl (meth)acrylate is more preferred.

[0132] When using a hydroxyl-containing monomer (a2) as a monomer component, the content of the hydroxyl-containing monomer (a2) is generally more than 0.01% by weight and less than 10% by weight among all monomer components forming the (meth)acrylic polymer (A).

[0133] The (meth)acrylic polymer (A) preferably contains monomers with unsaturated carbon double bonds having a glass transition temperature of 0°C or higher as monomer components. Examples of monomers (a3) ​​with unsaturated carbon double bonds having a glass transition temperature of 0°C or higher as homopolymers include (meth)acrylic acid alkyl ester monomers and (meth)acrylic acid. Monomer (a3) ​​is preferably a monomer with unsaturated carbon double bonds having a glass transition temperature of 20°C or higher as homopolymer, and more preferably a monomer with unsaturated carbon double bonds having a glass transition temperature of 40°C or higher as homopolymer.

[0134] In the (meth)acrylic polymer (A), the proportion of monomer (a3) ​​is not particularly limited. The content is typically 0.1% to 40% by weight, more preferably 1% to 30% by weight. Furthermore, when two or more monomers (a3) ​​are used together, the content is the total content.

[0135] Examples of monomers (a3) ​​include: methyl acrylate (Tg: 8℃), methyl methacrylate (Tg: 105℃), ethyl methacrylate (Tg: 65℃), n-propyl acrylate (Tg: 3℃), n-propyl methacrylate (Tg: 35℃), n-pentyl acrylate (Tg: 22℃), n-tetradecyl acrylate (Tg: 24℃), n-hexadecyl acrylate (Tg: 35℃), n-hexadecyl methacrylate (Tg: 15℃), n-octadecyl acrylate (Tg: 30℃), and n-octadecyl methacrylate (Tg: 15℃). (g: 38℃) and other straight-chain alkyl methacrylates; tert-butyl acrylate (Tg: 43℃), tert-butyl methacrylate (Tg: 48℃), isopropyl methacrylate (Tg: 81℃), and isobutyl methacrylate (Tg: 48℃) and other branched-chain alkyl methacrylates; cyclohexyl acrylate (Tg: 19℃), cyclohexyl methacrylate (Tg: 65℃), isobornyl acrylate (Tg: 94℃), and isobornyl methacrylate (Tg: 180℃) and other cyclic alkyl methacrylates; acrylic acid (Tg: 106℃), etc. These can be used alone or in combination.

[0136] When the adhesive composition contains a crosslinking agent (described later), the comonomer becomes a reaction site with the crosslinking agent. Carboxyl-containing and hydroxyl-containing monomers are highly reactive with intermolecular crosslinking agents and are therefore preferably used to improve the cohesiveness or heat resistance of the resulting adhesive layer. Furthermore, carboxyl-containing monomers are preferred in terms of both durability and reprocessability, while hydroxyl-containing monomers are preferred in terms of improving reprocessability.

[0137] As a monomer component, other comonomers (a4) can be further used. These other comonomers (a4) may have polymerizable functional groups with unsaturated double bonds, such as (meth)acryloyl or vinyl groups. By using other comonomers (a4), the adhesion and heat resistance of the adhesive layer can be improved. These other comonomers (a4) can be used alone or in combination.

[0138] The adhesion of the adhesive layer can be improved by using amino-containing monomers and amide-containing monomers as other comonomers (a4). Examples of amino-containing monomers include N,N-dimethylaminoethyl methacrylate and N,N-dimethylaminopropyl methacrylate. Monomers containing amide groups include, for example: (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-isopropylacrylamide, N-methyl(meth)acrylamide, N-butyl(meth)acrylamide, N-hexyl(meth)acrylamide, N-hydroxymethyl(meth)acrylamide, N-hydroxymethyl-N-propane(meth)acrylamide, aminomethyl(meth)acrylamide, aminoethyl(meth)acrylamide, mercaptomethyl(meth)acrylamide, mercaptoethyl(meth)acrylamide, and other acrylamide monomers; N-(meth)acryloylmorpholine, N-(meth)acryloylpiperidine, N-(meth)acryloylpyrrolidine, and other N-acryloyl heterocyclic monomers; and N-vinylpyrrolidone, N-vinyl-ε-caprolactam, and other N-vinyl lactam monomers.

[0139] Other comonomers (a4) can also be multifunctional monomers. By using multifunctional monomers, the gel fraction of the adhesive layer can be adjusted or the cohesiveness can be controlled. Examples of multifunctional monomers include: hexanediol di(meth)acrylate (1,6-hexanediol di(meth)acrylate), butanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, allyl methacrylate, vinyl methacrylate, epoxy acrylate, polyester acrylate, urethane acrylate, and other multifunctional acrylates; and divinylbenzene. The preferred polyfunctional acrylates are 1,6-hexanediol diacrylate and dipentaerythritol hexa(meth)acrylate.

[0140] Other comonomers (a4) besides those mentioned above may include, for example: 2-methoxyethyl methacrylate, 2-ethoxyethyl methacrylate, methoxytriethylene glycol (meth)acrylate, 3-methoxypropyl methacrylate, 3-ethoxypropyl methacrylate, 4-methoxybutyl methacrylate, 4-ethoxybutyl methacrylate, and other alkoxyalkyl methacrylates; cyclizable monomers such as methyl 2-(allyloxymeth)acrylate; and epoxy-containing monomers such as glycidyl methacrylate and methyl glycidyl methacrylate. Monomers containing sulfonic acid groups, such as sodium vinyl sulfonate; monomers containing phosphoric acid groups; (meth)acrylates with alicyclic hydrocarbon groups, such as cyclopentyl methacrylate, cyclohexyl methacrylate, and isobornyl methacrylate; (meth)acrylates with aromatic hydrocarbon groups, such as phenyl methacrylate, phenoxyethyl methacrylate, and benzyl methacrylate; vinyl esters, such as vinyl acetate and vinyl propionate; aromatic vinyl compounds, such as styrene and vinyltoluene; olefins or dienes, such as ethylene, propylene, butadiene, isoprene, and isobutylene; vinyl ethers, such as vinyl alkyl ethers; and vinyl chloride.

[0141] The content of other comonomers (a4) in the (meth)acrylic polymer is preferably 20% by mass or less, more preferably 10% by mass or less, even more preferably 8% by mass or less, and particularly preferably 5% by mass or less.

[0142] The weight-average molecular weight (Mw) of the (meth)acrylic polymer (A) is, for example, 200,000 to 3,000,000, preferably 1,000,000 to 2,500,000, and more preferably 1,200,000 to 2,500,000. When the weight-average molecular weight (Mw) is within this range, an adhesive layer with excellent durability (especially heat resistance) can be obtained. If the weight-average molecular weight (Mw) exceeds 3,000,000, there is an increase in viscosity and / or gelation during polymer polymerization.

[0143] D-2-2. Silane coupling agents containing reactive functional groups

[0144] The adhesive composition may contain a silane coupling agent with reactive functional groups. The reactive functional groups of the silane coupling agent are typically functional groups other than acid anhydride groups. Examples of functional groups other than acid anhydride groups include epoxy, mercapto, amino, isocyanate, isocyanurate, vinyl, styryl, acetoacetyl, urea, thiourea, (meth)acrylate, heterocyclic groups, and combinations thereof. The silane coupling agent with reactive functional groups can be used alone or in combination.

[0145] When a silane coupling agent containing reactive functional groups is formulated into an adhesive composition, the amount of the silane coupling agent containing reactive functional groups is typically 0.001 parts by weight or more and 5 parts by weight or less relative to 100 parts by weight of the (meth)acrylic polymer (A).

[0146] D-2-3. Crosslinking agent

[0147] The adhesive composition may contain a crosslinking agent. As a crosslinking agent, organic crosslinking agents, multifunctional metal chelates, etc., can be used. Examples of organic crosslinking agents include isocyanate-based crosslinking agents, peroxide-based crosslinking agents, epoxy-based crosslinking agents, and imine-based crosslinking agents. Multifunctional metal chelates are formed by covalent or coordination bonding of multivalent metals with organic compounds. When the adhesive composition is radiation-curable, multifunctional monomers can be used as crosslinking agents. Crosslinking agents can be used alone or in combination.

[0148] When a crosslinking agent is formulated into an adhesive composition, the amount of crosslinking agent formulated is typically 0.01 parts by weight or more and 15 parts by weight or less relative to 100 parts by weight of the (meth)acrylic polymer (A).

[0149] When an isocyanate-based crosslinking agent is formulated into an adhesive composition, the amount of the isocyanate-based crosslinking agent formulated is typically 0.01 parts by weight or more and 15 parts by weight or less relative to 100 parts by weight of the (meth)acrylic polymer.

[0150] When peroxides are formulated into adhesive compositions, the amount of peroxide formulated is typically 0.01 parts by weight or more and 2 parts by weight or less per 100 parts by weight of the (meth)acrylic polymer. Within this range, processability and crosslinking stability can be easily adjusted.

[0151] D-2-4. Additives

[0152] The adhesive composition may also contain (meth)acrylic oligomers and / or ionic compounds. Additionally, the adhesive composition may contain additives. Specific examples of additives include: colorants, pigments and other powders, dyes, surfactants, plasticizers, adhesive agents, surface lubricants, leveling agents, softeners, antioxidants, anti-aging agents, light stabilizers, ultraviolet absorbers, polymerization inhibitors, inorganic or organic fillers, metal powders, granular or foil-like substances. Furthermore, within a controllable range, a redox system with a reducing agent can be used. The type, quantity, combination, and content of additives can be appropriately set according to the purpose. The content of additives is preferably 5 parts by weight or less, more preferably 3 parts by weight or less, and even more preferably 1 part by weight or less, relative to 100 parts by weight of the (meth)acrylic polymer (A).

[0153] E. Image display device

[0154] The polarizers with phase retardation layers and adhesive layers described in items A through D above can be applied to image display devices. Therefore, embodiments of the present invention also include image display devices using such polarizers with phase retardation layers and adhesive layers. Representative examples of image display devices include liquid crystal displays and organic EL displays. A representative example of an image display device according to embodiments of the present invention is that it has a polarizer with phase retardation layers and adhesive layers described in items A through D above on its viewable side.

[0155] Example

[0156] The present invention will be specifically described below through examples, but the present invention is not limited to these examples. Furthermore, the methods for measuring each characteristic are as follows.

[0157] (1) Paste offset

[0158] The polarizers with phase retardation and adhesive layers obtained in the examples and comparative examples were cut to specified dimensions (M or T dimensions in Table 1 below) as test samples. These test samples were subjected to a heating test at 85°C for 500 hours. The amount of the first adhesive layer overflowing from the end faces of the polarizer and phase retardation layer after the heating test was observed and measured using an objective lens (20x). The length of the portion of the first adhesive layer with the largest overflow was taken as the paste offset. The observation was adjusted so that the transmitted light was 0 (zero) and the observation was performed using reflected light.

[0159] (2) Creep value

[0160] The polarizers with phase retardation layers and adhesive layers obtained in the examples and comparative examples were cut into 10mm × 30mm pieces as test samples. The upper 10mm × 10mm portion of the test sample was attached to an SUS (Steel Use Stainless) plate via a second adhesive layer. A load of 500gf was applied vertically downwards from the lower portion of the test sample. The offset between the test sample and the SUS plate was measured after 1 second and 3600 seconds of the applied load, and these offsets were recorded as Cr1 and Cr2, respectively. 3600 . Will be composed of Cr1 and Cr 3600 The creep value is obtained by using the following formula: ΔCr.

[0161] ΔCr=Cr 3600 -Cr1

[0162] (3) Uneven color

[0163] The polarizers with phase retardation layers and adhesive layers obtained in the examples and comparative examples were cut to specified dimensions (M or T dimensions in Table 1 below) and bonded to a glass plate via a second adhesive layer as test samples. The test samples, heated at 85°C for 500 hours, were placed on a reflective plate (DMS vapor-deposited film manufactured by Toray Thin Film Processing Co., Ltd.). A spectrophotometer (manufactured by Konica Minolta, product name "CM-2600d") was used to measure the reflected hue a at the center of the sample. * C and b * C and the reflected hue a at the end of the sample * E and b * E The measurement was performed. Δab, calculated using the following formula, was used as an indicator of color unevenness. The smaller Δab is, the better the color unevenness.

[0164] Δab={(a * E -a * C ) 2 +(b * E -b * C ) 2} 1 / 2

[0165] [Abbreviation for compound]

[0166] The abbreviations of the compounds used in the following manufacturing examples are as follows.

[0167] ·BPFM: bis[9-(2-phenoxycarbonylethyl)fluorene-9-yl]methane

[0168] It was synthesized using the method described in Japanese Patent Application Publication No. 2015-25111.

[0169] [Chemical structural formula 5]

[0170]

[0171] • ISB: Isosorbide [manufactured by Roquette Freres]

[0172] • SPG: Spirodiol [Manufactured by Mitsubishi Gas Chemical Co., Ltd.]

[0173] • DPC: Diphenyl carbonate [manufactured by Mitsubishi Chemical Corporation]

[0174] [Manufacturing Example 1: Fabrication of the retardation film constituting the retardation layer]

[0175] Polymerization was carried out using a batch polymerization apparatus consisting of two vertical stirred reactors equipped with agitators and reflux coolers. BPFM 30.31 parts by mass (0.047 mol), ISB 39.94 parts by mass (0.273 mol), SPG 30.20 parts by mass (0.099 mol), DPC 69.67 parts by mass (0.325 mol), and calcium acetate monohydrate 7.88 × 10⁻⁶ as a catalyst were added. -4 Parts by weight (4.47 × 10) -6 (mol). After purging the reactor with nitrogen under reduced pressure, it is heated using a heat transfer medium, and stirring begins when the internal temperature reaches 100°C. Forty minutes after the start of heating, the internal temperature reaches 220°C and is maintained at this temperature while simultaneously reducing the pressure. After 90 minutes of reaching 220°C, the pressure drops to 13.3 kPa. Phenol vapor, a byproduct of the polymerization reaction, is introduced into a reflux cooler at 110°C, returning a certain amount of monomer components contained in the phenol vapor to the reactor. Uncondensed phenol vapor is then recovered in a condenser at 45°C. Nitrogen is introduced into the first reactor, temporarily restoring the pressure to atmospheric pressure. The oligomerized reaction liquid from the first reactor is then transferred to the second reactor. Heating and depressurization are then initiated in the second reactor, raising the internal temperature to 240°C and the pressure to 20 kPa over 40 minutes. Subsequently, polymerization continues while gradually reducing the pressure until the specified stirring force is achieved. When the specified kinetic energy is reached, nitrogen gas is introduced into the reactor for repressurization, extruding the generated polyester carbonate into water. The strands are then cut to obtain granules. This resin is called "PC1". The ratio of structural units derived from each monomer is BPFM / ISB / SPG / DPC = 21.5 / 39.4 / 30.0 / 9.1% by mass. PC1 has a reduced viscosity of 0.46 dL / g, a Mw of 48,000, and a refractive index n. D The coefficient of performance is 1.526, the melt viscosity is 2480 Pa·s, the glass transition temperature is 139℃, and the photoelastic modulus is 9×10⁻⁶. -12 [m 2 The wavelength dispersion Re(450) / Re(550) is 0.85.

[0176] Dianal BR80 (manufactured by Mitsubishi Chemical Corporation) was used as the acrylic resin, and the obtained polyester carbonate was extruded and compounded. The mixture of polycarbonate granules (99.5 parts by weight) and BR80 powder (0.5 parts by weight) was fed into a TEX30HSS twin-screw extruder manufactured by Japan Steel Works Co., Ltd. The extruder cylinder temperature was set to 250°C, and extrusion was carried out at a throughput of 12 kg / hr and a screw speed of 120 rpm. The extruder was also equipped with a vacuum vent to allow the molten resin to evaporate under reduced pressure during extrusion. The resin composition granules obtained in this way were vacuum dried at 100°C for at least 6 hours. Then, using a film-forming apparatus equipped with a single-screw extruder (manufactured by Isuzu Kakoki, screw diameter 25mm, feed cylinder set temperature: 250°C), a T-die (width 300mm, set temperature: 220°C), a cooling roller (set temperature: 120-130°C), and a winding machine, a long, unstretched film with a length of 3m, a width of 200mm, and a thickness of 100μm was produced. This long, unstretched film was stretched at a stretching temperature Tg and a stretch ratio of 2.4. The resulting stretched film was subjected to a tempering treatment (tempering temperature 130°C, tempering ratio 4.5%), and then subjected to a heat treatment at 125°C for 2 minutes.

[0177] Thus, a retardation film R1 constituting the retardation layer was obtained. The shrinkage rate of the retardation film R1 in the slow axis direction after heating at 125°C for 180 minutes was 2.92%. In addition, the retardation film R1 exhibits refractive index characteristics of nx>ny>nz, Re(550) is 145nm, and Re(450) / Re(550) is 0.85.

[0178] [Manufacturing Example 2: Fabrication of the retardation film constituting the retardation layer]

[0179] Except for the absence of easing and heating treatments, the retardation film R2 was obtained in the same manner as in Manufacturing Example 1. The shrinkage rate of the retardation film R2 in the slow axis direction after heating at 125°C for 180 minutes was 4.54%. In addition, the retardation film R2 exhibited refractive index characteristics of nx>ny>nz, Re(550) was 145 nm, and Re(450) / Re(550) was 0.85.

[0180] [Manufacturing Example 3: Preparation of Adhesive]

[0181] (Preparation of acrylic polymer A1)

[0182] A monomer mixture containing 99 parts of butyl acrylate and 1 part of 4-hydroxybutyl acrylate was added to a four-necked flask equipped with a stirrer, thermometer, nitrogen inlet pipe, and cooler. Then, relative to 100 parts of this monomer mixture, 0.1 parts of 2,2'-azobisisobutyronitrile (2,2'-Azobisisobutyronitrile) as a polymerization initiator and 100 parts of ethyl acetate were added together. Nitrogen gas was introduced while the mixture was slowly stirred to purge the nitrogen. The liquid temperature in the flask was maintained at approximately 55°C, and the polymerization reaction was carried out for 8 hours to prepare a solution of an acrylic polymer A1 with a weight-average molecular weight (Mw) of 1.8 million and Mw / Mn = 4.8.

[0183] (Preparation of adhesive)

[0184] To obtain adhesive PSA1, 0.02 parts of trimethylolpropane / phenylene diisocyanate adduct (manufactured by Tosoh Corporation, trade name "Takenate D110N"), 0.3 parts of peroxide crosslinking agent (manufactured by Nippon Yushi Co., Ltd., trade name "Nyper BMT"), and 0.2 parts of epoxy-containing silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBM-403") were mixed with 100 parts of the solid component of acrylic polymer A1 solution.

[0185] [Manufacturing Example 4: Preparation of Adhesive]

[0186] Except for changing the amount of D110N to 0.1 parts, the adhesive PSA2 was obtained in the same manner as in Manufacturing Example 3.

[0187] [Manufacturing Example 5: Preparation of Adhesive]

[0188] (Preparation of acrylic polymer A2)

[0189] Except for using a monomer mixture containing 94.9 parts of butyl acrylate, 0.1 parts of 2-hydroxyethyl acrylate and 5 parts of acrylic acid, a solution of acrylic polymer A2 with Mw of 2.3 million and Mw / Mn = 3.9 was prepared in the same manner as in Manufacturing Example 3.

[0190] (Preparation of adhesive)

[0191] To obtain adhesive PSA3, 0.6 parts of trimethylolpropane / toluene diisocyanate adduct (manufactured by Tosoh Corporation, trade name "Coronate L"), 0.2 parts of peroxide crosslinking agent (manufactured by Nippon Yushi Co., Ltd., trade name "Nyper BMT"), and 0.2 parts of epoxy-containing silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBM-403") were added relative to 100 parts of the solid component of acrylic polymer A2 solution.

[0192] [Manufacturing Example 6: Preparation of Adhesive]

[0193] (Preparation of acrylic polymer A3)

[0194] Except for using a monomer mixture containing 91 parts butyl acrylate, 6 parts N-acryloylmorpholine, 0.3 parts 4-hydroxybutyl acrylate and 2.7 parts acrylic acid, a solution of acrylic polymer A3 with Mw of 2.7 million and Mw / Mn = 3.8 was prepared in the same manner as in Manufacturing Example 3.

[0195] (Preparation of adhesive)

[0196] To obtain adhesive PSA4, 0.1 parts of trimethylolpropane / toluene diisocyanate adduct (manufactured by Tosoh Corporation, trade name "Coronate L"), 0.3 parts of peroxide crosslinking agent (manufactured by Nippon Yushi Co., Ltd., trade name "Nyper BMT"), and 0.2 parts of epoxy-containing silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBM-403") were added relative to 100 parts of the solid component of acrylic polymer A3 solution.

[0197] [Manufacturing Example 7: Preparation of Adhesive]

[0198] (Preparation of acrylic polymer A4)

[0199] Except for using a monomer mixture containing 82.1 parts of butyl acrylate, 13 parts of benzyl acrylate, 0.1 parts of 4-hydroxybutyl acrylate and 4.8 parts of acrylic acid, a solution of acrylic polymer A4 with a Mw of 2.2 million was prepared in the same manner as in Manufacturing Example 3.

[0200] (Preparation of adhesive)

[0201] To obtain adhesive PSA5, 0.5 parts of a reactive silyl polyether compound (manufactured by Kaneka Corporation, trade name "Silyl SAT10"), 0.45 parts of a trimethylolpropane / toluene diisocyanate adduct (manufactured by Tosoh Corporation, trade name "Coronate L"), and 0.1 parts of a peroxide crosslinking agent (benzoyl peroxide) were mixed with 100 parts of the solid component of the acrylic polymer A4 solution.

[0202] [Example 8: Fabrication of a Polarizing Film]

[0203] (Making of a polarizing device)

[0204] A 12μm thick polarizer is produced by uniaxially stretching a long roll of polyvinyl alcohol (PVA) resin film (manufactured by Kuraray Co., Ltd., product name "PE3000") with a thickness of 30μm in the length direction using a roll stretching machine at a ratio of 5.9 times in the length direction. At the same time, swelling, dyeing, crosslinking, washing and finally drying are performed.

[0205] Specifically, the swelling treatment involves stretching the material to 2.2 times its original size while treating it with pure water at 20°C. Next, the dyeing treatment involves stretching the material to 1.4 times its original size while treating it with an aqueous solution at 30°C containing iodine and potassium iodide at a weight ratio of 1:7, with the iodine concentration adjusted to achieve a monomer transmittance of 45.0% for the obtained polarizer. Then, the crosslinking treatment employs a two-stage process. The first stage involves stretching the material to 1.2 times its original size while treating it with an aqueous solution containing boric acid and potassium iodide at 40°C. The aqueous solution for the first stage of crosslinking treatment contains 5.0 wt% boric acid and 3.0 wt% potassium iodide. The second stage involves stretching the material to 1.6 times its original size while treating it with an aqueous solution containing boric acid and potassium iodide at 65°C. The aqueous solution for the second stage of crosslinking treatment contains 4.3 wt% boric acid and 5.0 wt% potassium iodide. Finally, the washing treatment involves treating the material with an aqueous solution containing potassium iodide at 20°C. The aqueous solution for the washing treatment contains 2.6 wt% potassium iodide. Finally, the drying process involves drying at 70°C for 5 minutes to obtain the polarizer.

[0206] (Making of polarizing filters)

[0207] A triacetyl cellulose membrane (40 μm thick, manufactured by Konica Minolta, trade name "KC4UYW") is bonded to one side of the polarizer using a polyvinyl alcohol-based adhesive to obtain a polarizer P1 with a protective layer / polarizer configuration.

[0208] [Example 9: Fabrication of a Polarizing Film]

[0209] (Making of a polarizing device)

[0210] As a thermoplastic resin substrate, a strip-shaped amorphous polyethylene terephthalate copolymer film (thickness: 100 μm) with a Tg of about 75 °C is used to perform corona treatment on one side of the resin substrate.

[0211] Add 13 parts by weight of potassium iodide to 100 parts by weight of a PVA-based resin containing polyvinyl alcohol (degree of polymerization 4200, degree of saponification 99.2 mol%) and acetyl-modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "Gohsefimer") in a 9:1 ratio, and dissolve the resulting solution in water to prepare a PVA aqueous solution (coating solution).

[0212] The above-mentioned PVA aqueous solution is coated on the corona-treated surface of the resin substrate and dried at 60°C to form a PVA-based resin layer with a thickness of 13 μm, thereby producing a laminate.

[0213] The obtained laminate was uniaxially stretched to 2.4 times its original length in an oven at 130°C (air-assisted stretching treatment).

[0214] Then, the laminate was immersed in an insoluble bath (an aqueous solution of boric acid prepared by mixing 4 parts by weight of boric acid with 100 parts by weight of water) at a liquid temperature of 40°C for 30 seconds (insoluble treatment).

[0215] Next, while adjusting the concentration so that the final polarizer's monomer transmittance (Ts) becomes the desired value, the sample is immersed in a staining bath (an iodine aqueous solution prepared by mixing iodine and potassium iodide in a weight ratio of 1:7 relative to 100 parts by weight of water) at a liquid temperature of 30°C for 60 seconds (staining treatment).

[0216] Then, it is immersed in a crosslinking bath (an aqueous solution of boric acid prepared relative to 100 parts by weight of water, 3 parts by weight of potassium iodide, and 5 parts by weight of boric acid) at a liquid temperature of 40°C for 30 seconds (crosslinking treatment).

[0217] Subsequently, while immersing the laminate in a boric acid aqueous solution (boric acid concentration of 4 wt% and potassium iodide concentration of 5 wt%) at a liquid temperature of 70°C, uniaxial stretching (underwater stretching treatment) is performed between rolls with different circumferential speeds in the longitudinal direction (length direction) with a total stretching ratio of 5.5.

[0218] The laminate was then immersed in a washing bath at 20°C (an aqueous solution prepared by adding 4 parts by weight of potassium iodide to 100 parts by weight of water) (washing treatment).

[0219] Then, while drying in an oven maintained at approximately 90°C, it is in contact with SUS heated rollers maintained at a surface temperature of approximately 75°C (drying shrinkage treatment).

[0220] Thus, a polarizer with a thickness of about 5 μm is formed on the resin substrate, resulting in a polarizer with a resin substrate / polarizer structure.

[0221] (Making of polarizing filters)

[0222] A cyclic olefin film (manufactured by Zeon Corporation, Japan, ZF-12, 23 μm) serving as a protective layer is bonded to the surface of the obtained polarizer (the side opposite to the resin substrate) using a UV-curable adhesive. Specifically, the adhesive is applied with a total thickness of approximately 1.0 μm using a roller mill. Then, UV light is irradiated from the cyclic olefin film side to cure the adhesive. Finally, the resin substrate is peeled off to obtain a polarizer P2 having the cyclic olefin film (protective layer) / polarizer configuration.

[0223] [Examples 1-5 and Comparative Examples 1-8]

[0224] A polarizer, a retardation film (retardation layer), and adhesives (a first adhesive layer and a second adhesive layer) were combined as shown in Table 1 to fabricate a polarizer with a retardation layer and adhesive layers. The polarizer and the retardation layer (retardation film) were bonded at a 45° angle between the absorption axis of the polarizer and the slow axis of the retardation film. The resulting polarizer with the retardation layer and adhesive layers was used for the evaluation of color unevenness. The results, along with the paste offset of the first adhesive layer, the shrinkage rate of the retardation layer, and the creep value of the second adhesive layer, are shown in Table 1. Furthermore, in Table 1, "M" in the "Dimensions" column refers to a dimension of 77.4 mm × 162.3 mm, and "T" refers to a dimension of 159.5 mm × 244.5 mm.

[0225] [Table 1]

[0226]

[0227] [evaluate]

[0228] As shown in Table 1, by combining and controlling the paste offset of the first adhesive layer, the shrinkage rate of the phase difference layer, and the creep value of the second adhesive layer, a polarizer with a phase difference layer and an adhesive layer can be obtained to achieve the suppression of color unevenness in an image display device under high temperature conditions.

[0229] Industrial availability

[0230] The polarizer with phase retardation layer and adhesive layer of the present invention is suitable for use in image display devices (such as liquid crystal display devices and organic EL display devices).

[0231] Symbol Explanation

[0232] 10 Polarizing filters

[0233] 11. Polarizer

[0234] 12 First protective layer

[0235] 13 Second protective layer

[0236] 20 First adhesive layer

[0237] 30: Phase difference layer

[0238] 40 Second adhesive layer

[0239] 100 Polarizers with Phase Retardation Layer and Adhesive Layer

Claims

1. A polarizing plate with a phase difference layer and an adhesive layer, having: a polarizing plate including a polarizer; a phase difference layer attached to the polarizing plate via a first adhesive layer; and a second adhesive layer provided as an outermost layer on a side of the phase difference layer opposite to the polarizing plate; Re(450) and Re(550) are in-plane retardations measured at 23°C using light having wavelengths of 450 nm and 550 nm, respectively; a paste shift amount of the first adhesive layer after a heating test at 85°C for 500 hours is 300 μm or more; the phase difference layer contains: a resin including at least one linking group selected from a carbonate bond and an ester bond and at least one structural unit selected from a structural unit represented by the following general formula (1) and a structural unit represented by the following general formula (2), and having positive refractive index anisotropy; and an acrylic resin, The phase difference layer is composed of a stretched film of a resin film, satisfies a relationship of Re(450) < Re(550), and has a slow axis direction shrinkage rate of 4% or less when heated at 80°C to 125°C for a period of 180 minutes, wherein the content of the acrylic resin is 0.5 to 2.0 mass%, the acrylic resin contains 70 mass% or more of a structural unit derived from methyl methacrylate, and the weight average molecular weight Mw of the acrylic resin is 10,000 to 200,000, [Chemical Structural Formula 1] [Chemical Structural Formula 2] Re(550) of the phase difference layer is 100 nm to 200 nm, and the angle formed by the slow axis of the phase difference layer and the absorption axis of the polarizer is 40° to 50° or 130° to 140°. The thickness of the phase difference layer is 15 μm to 60 μm. The stretched film constituting the phase difference layer is a film obtained by subjecting a film to a heating treatment at a temperature of 105°C or higher for 2 minutes or more. Another phase difference layer having a refractive index characteristic showing a relationship of nz>nx=ny is further provided between the phase difference layer and the second adhesive layer. 6.An image display device provided with the polarizing plate with a phase difference layer and an adhesive layer according to any one of claims 1 to 5. In general formulas (1) and (2), R 1 ~R 3 R are, independently, alkylene groups having 1 to 4 carbon atoms, either directly bonded, substituted, or unsubstituted. 4 ~R 9 Each of the following is independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 4 to 10 carbon atoms, a substituted or unsubstituted acyl group having 1 to 10 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms, a substituted or unsubstituted aryloxy group having 1 to 10 carbon atoms, a substituted or unsubstituted amino group, a substituted or unsubstituted vinyl group having 1 to 10 carbon atoms, a substituted or unsubstituted ethynyl group having 1 to 10 carbon atoms, a sulfur atom having a substituent, a silicon atom having a substituent, a halogen atom, a nitro group, or a cyano group; wherein, R 4 ~R 9 They can be the same or different, R 4 ~R 9 At least two adjacent groups can also bond together to form a ring.

2. The polarizing plate with a phase difference layer and an adhesive layer according to claim 1, wherein, ​ 3. The polarizing plate with a phase difference layer and an adhesive layer according to claim 1 or 2, wherein, ​ 4. The polarizing plate with a phase difference layer and an adhesive layer according to claim 1 or 2, wherein, ​ 5. The polarizing plate with a phase difference layer and an adhesive layer according to claim 1 or 2, wherein ​ ​

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