TW202140257A - Polarizing plate with retardation layer and adhesive layer, and image display device using polarizing plate with retardation layer and adhesive layer - Google Patents

Abstract

Provided are a polarizing plate which is equipped with a retardation layer and an adhesive layer and with which an image display device, in which phase difference unevenness is suppressed in high temperature environments and color unevenness is suppressed in high temperature environments, can be achieved. This the polarizing plate equipped with a retardation layer and an adhesive layer includes: 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 the outermost layer on the retardation layer on the side opposite to 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 shrinkage rate of 4% or less in the slow axis direction when heated 180 minutes at 80-125 DEG C. The paste shift amount of the first adhesive layer after a heating test at 85 DEG C for 500 hours is 300 [mu]m or greater.

Description

Polarizing plate with retardation layer and adhesive layer, and image display device using the polarizing plate with retardation layer and adhesive layer

The invention relates to a polarizing plate with a retardation layer and an adhesive layer, and an image display device using the polarizing plate with the retardation layer and the adhesive layer.

In recent years, image display devices represented by liquid crystal display devices and electroluminescence (EL) display devices (for example, organic EL display devices and inorganic EL display devices) have rapidly spread. The image display device typically uses a polarizing plate and a phase difference plate. In practical applications, a polarizing plate with a retardation layer formed by integrating a polarizing plate and a retardation plate is widely used (for example, Patent Document 1). However, the polarizing plate with the retardation layer will have uneven retardation in a high temperature environment. As a result, the image display device may have uneven color in a high temperature environment. Prior art literature Patent literature

Patent Document 1: Japanese Patent No. 3325560

[The problem to be solved by the invention]

The present invention was developed to solve the above-mentioned previous problems, and its main purpose is to provide a polarizing plate with a retardation layer and an adhesive layer, which can realize the suppression of the unevenness of the retardation in a high temperature environment and the color in a high temperature environment An image display device that suppresses unevenness. [Technical means to solve the problem]

[化2]

通式(1)及(2)中，R¹ ～R³ 分別獨立地為直接鍵、經取代或未經取代之碳數1～4之伸烷基，R⁴ ～R⁹ 分別獨立地為氫原子、經取代或未經取代之碳數1～10之烷基、經取代或未經取代之碳數4～10之芳基、經取代或未經取代之碳數1～10之醯基、經取代或未經取代之碳數1～10之烷氧基、經取代或未經取代之碳數1～10之芳氧基、經取代或未經取代之胺基、經取代或未經取代之碳數1～10之乙烯基、經取代或未經取代之碳數1～10之乙炔基、具有取代基之硫原子、具有取代基之矽原子、鹵素原子、硝基或氰基；其中，R⁴ ～R⁹ 相互可相同亦可不同，R⁴ ～R⁹ 中相鄰之至少2個基亦可相互鍵結而形成環。 根據本發明之另一方面，提供一種圖像顯示裝置。該圖像顯示裝置具備上述附相位差層及黏著劑層之偏光板。 [發明之效果]The polarizing plate with retardation layer and adhesive layer according to the embodiment of the present invention has: a polarizing plate including a polarizing element; a retardation layer bonded to the polarizing plate via a first adhesive layer; and a second adhesive The layer, which is provided as the outermost layer on the side of the retardation layer opposite to the polarizing plate. The retardation layer includes a stretched film of a resin film, which satisfies the relationship of Re(450)<Re(550), and has a shrinkage rate of 4% or less in the slow axis direction when heated at 80°C to 125°C for 180 minutes. The paste offset of the first adhesive layer after a heating test at 85°C and 500 hours is 300 μm or more. Here, Re(450) and Re(550) are the in-plane phase differences measured by light with wavelengths of 450 nm and 550 nm at 23°C, respectively. In one embodiment, the Re(550) of the retardation layer is 100 nm to 200 nm, and the angle formed by the slow axis of the retardation layer and the absorption axis of the polarizing element is 40°-50° or 130°～140°. In one embodiment, the thickness of the retardation layer is 15 μm to 60 μm. In one embodiment, the stretched film constituting the retardation layer is one that has been heated at a temperature of 105° C. or higher for 2 minutes or longer. In one embodiment, the polarizing plate with a retardation layer and an adhesive layer further has a refractive index characteristic between the retardation layer and the second adhesive layer, and another one showing the relationship of nz>nx=ny Phase difference layer. In one embodiment, the retardation layer contains at least one bonding group selected from the group consisting of carbonate bonds and ester bonds, and structural units selected from the following general formula (1), and At least one structural unit in the group consisting of structural units represented by the following general formula (2), and a resin with positive refractive index anisotropy; and acrylic resin; and the content of the acrylic resin is 0.5 mass % To 2.0% by mass, the acrylic resin contains more than 70% by mass of structural units derived from methyl methacrylate, and its weight average molecular weight Mw is 10,000 to 200,000. [化1]

[化2]

In the general formulas (1) and (2), R ¹ to R ³ are each independently a direct bond, a substituted or unsubstituted alkylene group having 1 to 4 carbon atoms, and R ⁴ to R ⁹ are each independently hydrogen Atom, substituted or unsubstituted alkyl group with 1-10 carbons, substituted or unsubstituted aryl group with 4-10 carbons, substituted or unsubstituted acyl group with 1-10 carbons, Substituted or unsubstituted alkoxy with 1 to 10 carbons, substituted or unsubstituted aryloxy with 1 to 10 carbons, substituted or unsubstituted amine, substituted or unsubstituted A vinyl group with 1 to 10 carbons, a substituted or unsubstituted ethynyl group with 1 to 10 carbons, a sulfur atom with a substituent, a silicon atom with a substituent, a halogen atom, a nitro group or a cyano group; R ⁴ to R ⁹ may be the same or different from each other, ^{and at least two adjacent groups among R 4} to R ⁹ may be bonded to each other to form a ring. According to another aspect of the present invention, an image display device is provided. This image display device includes the above-mentioned polarizing plate with a retardation layer and an adhesive layer. [Effects of the invention]

According to the embodiment of the present invention, by optimizing the paste offset of the adhesive layer between the polarizing element and the retardation layer and the heat shrinkage rate of the retardation layer in the direction of the retardation axis, it is possible to achieve Polarizing plate with retardation layer and adhesive layer that can suppress uneven retardation in high temperature environment. As a result, an image display device in which color unevenness can be suppressed in a high-temperature environment can be realized.

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

(Definition of terms and symbols) The definitions of terms and symbols in this manual are as follows. (1) Refractive index (nx, ny, nz) "Nx" is the refractive index in the direction where the in-plane refractive index becomes the largest (i.e., the direction of the late axis), "ny" is the refractive index in the direction orthogonal to the late axis (i.e., the direction of the advancing axis) in the plane, " nz" is the refractive index in the thickness direction. (2) In-plane phase difference (Re) "Re(λ)" is the in-plane phase difference of the film measured by light with a wavelength of λ nm at 23°C. For example, "Re(450)" is the in-plane retardation of the film measured using light with a wavelength of 450 nm at 23°C. Re(λ) is calculated by the formula: Re=(nx-ny)×d when the thickness of the film is d(nm). (3) Phase difference in thickness direction (Rth) "Rth(λ)" is the phase difference in the thickness direction of the film measured by light with a wavelength of λ nm at 23°C. For example, "Rth(450)" is the retardation in the thickness direction of the film measured by light with a wavelength of 450 nm at 23°C. Rth(λ) is calculated by the formula: Rth=(nx-nz)×d when the thickness of the film is d(nm). (4) Nz coefficient The Nz coefficient is calculated by Nz=Rth/Re. (5) Angle In this specification, when referring to an angle, unless otherwise specified, the angle includes the angle in both clockwise and counterclockwise directions.

A. The overall composition of the polarizing plate with retardation layer and adhesive layer Fig. 1 is a schematic cross-sectional view of a polarizing plate with a retardation layer and an adhesive layer according to one embodiment of the present invention. The polarizing plate 100 with a retardation layer and an adhesive layer in the illustrated example has: a polarizing plate 10; a retardation layer 30 which is bonded to the polarizing plate 10 via a first adhesive layer 20; and a second adhesive layer 40, It is provided as the outermost layer on the side of the retardation layer 30 opposite to the polarizing plate 10. The polarizing plate with the retardation layer and the adhesive layer can be attached to the image display unit through the second adhesive layer 40. The polarizing plate 10 includes a polarizing element 11, a first protective layer 12 arranged on one side of the polarizing element 11, and a second protective layer 13 arranged on the other side of the polarizing element 11. Depending on the purpose, one of the first protective layer 12 and the second protective layer 13 may be omitted. For example, the retardation layer 30 can also function as a protective layer of the polarizing element 11, so the second protective layer 13 can be omitted. The angle formed by the slow axis of the retardation layer 30 and the absorption axis of the polarizing element 11 is preferably 40°-50°, more preferably 42°-48°, still more preferably 44°-46°, and particularly preferably It is about 45°, or preferably 130° to 140°, more preferably 132° to 138°, still more preferably 134° to 136°, particularly preferably about 135°.

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

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 the other retardation layer, typically, the refractive index characteristic shows the relationship of nz>nx=ny. By providing such another retardation layer, the reflection in the oblique direction can be well prevented, and the wide viewing angle of the anti-reflection function can be realized.

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 a conductive layer or an isotropic substrate with a conductive layer is provided, a polarizing plate with a retardation layer and an adhesive layer can be used to assemble between an image display unit (such as an organic EL unit) and a polarizing plate There is a so-called internal touch panel type input display device with a touch sensor. A conductive layer or an 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 a conductive layer or an isotropic substrate with a conductive layer are typically provided in order from the retardation layer 30 side.

The polarizing plate with retardation layer and adhesive layer may have another retardation layer (not shown). The other retardation layer may be combined with another retardation layer, or may be set alone (that is, without providing another retardation layer). The optical characteristics (for example, refractive index characteristics, in-plane retardation, Nz coefficient, photoelastic coefficient), thickness, arrangement position, etc. of the other retardation layer can be appropriately set according to the purpose.

The polarizing plate with the retardation layer and the adhesive layer can be in the shape of a sheet or in a strip shape. In this specification, the term "long strip" means an elongated shape with a very long length relative to the width, for example, includes an elongated shape with a length of 10 times or more, preferably 20 times or more, relative to the width. The long polarizing plate with retardation layer and adhesive layer can be wound into a roll.

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

Hereinafter, the constituent elements of the polarizing plate with the retardation layer and the adhesive layer will be described.

B. Polarizing element As the polarizing element 11, any suitable polarizing element can be used. For example, the resin film forming the polarizing element may be a single-layer resin film or a laminate of two or more layers.

As a specific example of a polarizing element containing a single-layer resin film, there may be mentioned: polyvinyl alcohol (PVA) film, partially formalized PVA film, vinyl -Hydrophilic polymer films such as vinyl acetate copolymer partially saponified films are dyed and stretched; polyene-based alignment films such as dehydrated PVA or dehydrochlorinated polyvinyl chloride. In terms of excellent optical properties, it is preferable to use a polarizing element obtained by dyeing a PVA-based film with iodine and performing uniaxial stretching.

The above-mentioned dyeing with iodine is performed, for example, by immersing the PVA-based film in an iodine aqueous solution. The stretching magnification of the above-mentioned uniaxial stretching is preferably 3 to 7 times. Stretching can be carried out after the dyeing treatment, or it can be carried out at the same time. Also, dyeing may be performed after stretching. If necessary, the PVA-based film is subjected to swelling treatment, cross-linking treatment, washing treatment, drying treatment, etc. For example, by immersing the PVA-based film in water for washing before dyeing, not only can the stain or anti-blocking agent on the surface of the PVA-based film be cleaned, but also the PVA-based film can be swelled to prevent uneven dyeing.

As a specific example of a polarizing element obtained by using a laminate, there may be mentioned: a laminate of a resin substrate and a PVA resin layer (PVA resin film) laminated on the resin substrate or a resin substrate and coating formation The polarizing element obtained by the laminate of the PVA-based resin layer of the resin substrate. A polarizing element obtained by using a laminate of a resin substrate and a PVA-based resin layer formed on the resin substrate can be produced by, for example, applying a PVA-based resin solution to the resin substrate and drying it. A PVA-based resin layer is formed on the resin substrate to obtain a laminate of the resin substrate and the PVA-based resin layer; and the laminate is extended and dyed to make the PVA-based resin layer into a polarizing element. In this embodiment, stretching typically includes immersing the laminate in a boric acid aqueous solution and stretching. Furthermore, the stretching may further include, if necessary, stretching the laminated body in the air at a high temperature (for example, 95°C or higher) before stretching in a boric acid aqueous solution. The obtained resin substrate/polarizing element laminate can be used directly (that is, the resin substrate can be used as the protective layer of the polarizing element), or the resin substrate can be peeled from the resin substrate/polarizing element laminate. The peeling surface is used by stacking any appropriate protective layer according to the purpose. The details of the manufacturing method of such a polarizing element are described in, for example, Japanese Patent Laid-Open No. 2012-73580 and Japanese Patent No. 6470455. The description of these patent documents is used in this specification by reference.

The polarizing element is preferably a resin film that may include a single layer. With such a configuration, it is possible to obtain a retardation layer and an adhesive layer that can suppress unevenness of retardation in a high-temperature environment by synergistic effects with the optimization of the first adhesive layer and the second adhesive layer The polarizing plate.

The thickness of the polarizing element is preferably 15 μm or less, more preferably 1 μm-12 μm, and still more preferably 3 μm-12 μm. If the thickness of the polarizing element is within this range, curling during heating can be well suppressed, and good appearance durability during heating can be obtained.

The polarizing element preferably exhibits absorption dichroism at any wavelength from 380 nm to 780 nm. The monomer transmittance of the polarizing element is, for example, 41.5%-46.0%, preferably 43.0%-46.0%, and more preferably 44.5%-46.0%. The degree of polarization of the polarizing element is preferably 97.0% or more, more preferably 99.0% or more, and still more preferably 99.9% or more.

C. Protective layer 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 of a polarizing element. Specific examples of the material as the main component of the film include: cellulose resins such as triacetyl cellulose (TAC); or polyester, polyvinyl alcohol, polycarbonate, and polyamide resins. , Polyimide series, polyether series, polysulfide series, polystyrene series, polynorene series, polyolefin series, (meth)acrylic series, acetate series and other transparent resins. In addition, thermosetting resins or ultraviolet curing resins such as (meth)acrylic, urethane, (meth)acrylate urethane, epoxy, and silicone resins can also be exemplified Wait. In addition to this, for example, glassy polymers such as silicone-based polymers may also be exemplified. In addition, the polymer film described in Japanese Patent Laid-Open No. 2001-343529 (WO01/37007) can also be used. As the material of the film, for example, a resin combination containing a thermoplastic resin having a substituted or unsubstituted imine group in the side chain and a thermoplastic resin having a substituted or unsubstituted phenyl group and a nitrile group in the side chain can be used For example, a resin composition having an alternating copolymer containing isobutylene and N-methylmaleimide and an acrylonitrile-styrene copolymer may be mentioned. The polymer film may be, for example, an extrusion molded product of the above-mentioned resin composition.

The polarizing plate with the retardation layer and the adhesive layer is typically arranged on the visible side of the image display device as described below, and the first protective layer 12 is typically arranged on the visible side. Therefore, the first protective layer 12 may also be subjected to surface treatments such as hard coating treatment, anti-reflection treatment, anti-sticking treatment, and anti-glare treatment as needed. Furthermore/or, the first protective layer 12 may optionally be subjected to processing to improve the visibility of the polarized sunglasses (typically, imparting (elliptical) circular polarization function and imparting ultra-high retardation). By implementing such a process, excellent visibility can also be achieved when viewing the display screen through a polarizing lens such as polarized sunglasses. Therefore, the polarizing plate with a retardation layer and an adhesive layer is also suitable for use in image display devices that can be used outdoors.

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 still more preferably 10 μm to 60 μm. Furthermore, when the surface treatment is performed, the thickness of the outer protective layer is the thickness including the thickness of the surface treatment layer.

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

C. Retardation layer C-1. Characteristics of retardation layer 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 still more preferably 130 nm to 150 nm. That is, the retardation layer can function as a so-called λ/4 plate.

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 exhibits the wavelength dependence of the reverse dispersion in which the retardation value increases according to the wavelength of the measurement light. The Re(450)/Re(550) of the retardation film, for example, exceeds 0.5 and does not reach 1.0, preferably 0.7 to 0.95, more preferably 0.75 to 0.92, and still more preferably 0.8 to 0.9. Re(650)/Re(550) is preferably 1.0 or more and less than 1.15, more preferably 1.03 to 1.1.

The retardation layer has an in-plane retardation as described above, and therefore has a relationship of nx>ny. As long as the retardation layer has a relationship of nx>ny, it exhibits any appropriate refractive index characteristics. The refractive index characteristics of the retardation layer typically show a relationship of nx>ny≧nz. Furthermore, here, "ny=nz" includes not only the case where ny and nz are completely equal, but also the case where they are substantially equal. Therefore, within a range that does not impair the effect of the present invention, there may be a situation 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 still more preferably 0.9 to 1.2. By satisfying this relationship, when a polarizing plate with a retardation layer and an adhesive layer is used in an image display device, a very excellent reflection hue can be achieved.

The thickness of the retardation layer can be set in a way that the λ/4 plate functions most appropriately. In other words, the thickness can be set in such a way that the required in-plane phase difference can be obtained. Specifically, the thickness is preferably 15 μm to 60 μm, more 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 including a normal resin film.

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

The elongation at break of the stretched film constituting the retardation layer is preferably 200% or more, more preferably 210% or more, still more preferably 220% or more, particularly preferably 245% or more. The upper limit of the elongation at break may be 500%, for example. The stretched film used in the retardation layer in the embodiment of the present invention is not only excellent in retardation performance, but also excellent in expandability. Therefore, the required in-plane phase can be achieved with a very thin thickness by virtue of these synergistic effects. Difference. Furthermore, in this specification, the so-called "elongation at break" refers to the elongation at break of the fixed-end uniaxially stretched media at a predetermined elongation temperature (for example, Tg-2°C).

Regarding the retardation layer, the absolute value of its photoelastic coefficient is preferably 20×10 ^-12 (m ² /N) or less, more preferably 1.0×10 ^-12 (m ² /N) to 15×10 ^-12 (m ² /N), more preferably 2.0×10 ^-12 (m ² /N) to 12×10 ^-12 (m ² /N). If the absolute value of the photoelastic coefficient is within this range, when the polarizing plate with the retardation layer and the adhesive layer is used in an image display device, display unevenness can be suppressed.

C-2. The constituent materials of the retardation layer The retardation layer typically contains a resin containing at least one bonding group selected from the group consisting of a carbonate bond and an ester bond. In other words, the retardation layer contains polycarbonate resin, polyester resin, or polyester carbonate resin (hereinafter, these may be collectively referred to as polycarbonate resin or the like). The polycarbonate resin or the like contains at least one structural unit selected from the group consisting of the structural unit represented by the general formula (1) and/or the structural unit represented by the general formula (2). These structural units are structural units derived from divalent oligomeric fluorescein, and are sometimes referred to as oligomeric structural units hereinafter. Such polycarbonate resins and the like have positive refractive index anisotropy.

Regarding the retardation layer, typically, it further contains an acrylic resin. The content of acrylic resin is 0.5% by mass to 1.5% by mass. Furthermore, in this manual, the percentage or part of the "mass" unit is synonymous with the percentage or part of the "weight" unit.

C-2-1. Polycarbonate-based resins and the like <oligomeric sulfide structural unit> The oligomeric sulfide structural unit is represented by the above-mentioned general formula (1) or (2). In the general formulas (1) and (2), R ¹ to R ³ are each independently a direct bond, a substituted or unsubstituted alkylene group having 1 to 4 carbon atoms, and R ⁴ to R ⁹ are each independently hydrogen Atom, substituted or unsubstituted alkyl group with 1-10 carbons, substituted or unsubstituted aryl group with 4-10 carbons, substituted or unsubstituted acyl group with 1-10 carbons, Substituted or unsubstituted alkoxy with 1 to 10 carbons, substituted or unsubstituted aryloxy with 1 to 10 carbons, substituted or unsubstituted amine, substituted or unsubstituted A vinyl group with 1-10 carbon atoms, a substituted or unsubstituted ethynyl group with a carbon number 1-10, a substituted sulfur atom, a substituted silicon atom, a halogen atom, a nitro group or a cyano group. Among them, R ⁴ to R ⁹ may be the same or different from each other, ^{and at least two adjacent groups among R 4} to R ⁹ may be bonded to each other to form a ring.

The content of the oligomeric structural unit in the polycarbonate resin etc. relative to the entire resin is preferably 1% to 40% by mass, more preferably 10% to 35% by mass, and still more preferably 15% to 30% by mass, particularly preferably 18% to 25% by mass. When the content of the oligomeric structural unit is too large, the following problems may occur: too large a photoelastic coefficient, insufficient reliability, and insufficient retardation performance. Furthermore, since the proportion of oligomeric fluoride structural units in the resin becomes higher, the range of molecular design is narrowed, and it is difficult to improve when the resin is required to be modified. On the other hand, even if the required inverse dispersion wavelength dependence is obtained by a very small amount of oligomeric structural units, in this case, the optical properties will change sensitively according to the slight deviation of the content of the oligomeric structural units. Therefore, there are situations in which it is not easy to manufacture in a manner in which various characteristics are controlled within a certain range.

The details of the oligomeric structural unit are described in the specification of International Publication No. 2015/159928, for example. This bulletin is used in this specification by reference.

＜Other structural units＞ Regarding polycarbonate resins and the like, it is typical to include other structural units in addition to the oligomeric fluoride structural unit. In one embodiment, other structural units are preferably derived from dihydroxy compounds or diester compounds. In order to show the target reverse wavelength dispersion, it is necessary to introduce the structural unit with positive intrinsic birefringence and the oligomeric structural unit with negative intrinsic birefringence into the polymer structure together, so it is used as other monomers for copolymerization, and then more It is preferably a dihydroxy compound or a diester compound as a raw material of a structural unit having positive birefringence.

As a comonomer, a compound which can introduce the structural unit containing an aromatic ring, and the compound which consists of an aliphatic structure which does not introduce the structural unit containing an aromatic ring can be mentioned, for example. Hereinafter, specific examples of the above-mentioned compound composed of an aliphatic structure will be given. Ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 1,5-heptanediol, 1, Dihydroxy compounds of linear aliphatic hydrocarbons such as 6-hexanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol; neopentyl glycol, hexanediol Dihydroxy compounds such as branched aliphatic hydrocarbons; 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,3-dihydroxyadamantane, hydrogenated bisphenol A, 2,2,4,4 -Dihydroxy compounds of secondary alcohols and tertiary alcohols exemplified by tetramethyl-1,3-cyclobutanediol, etc. as alicyclic hydrocarbons; 1,2-cyclohexanedimethanol, 1,3-cyclo Hexane dimethanol, 1,4-cyclohexane dimethanol, tricyclodecane dimethanol, pentacyclopentadecane dimethanol, 2,6-decahydronaphthalene dimethanol, 1,5-decahydronaphthalene dimethanol, 2,3-decahydronaphthalene dimethanol, 2,3-nordecane dimethanol, 2,5-nordecane dimethanol, 1,3-adamantane dimethanol, limonene and other dihydroxy compounds derived from terpene compounds Dihydroxy compounds exemplified as alicyclic hydrocarbon primary alcohols; oxyalkylene glycols such as diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, and polypropylene glycol; isosorbide Dihydroxy compounds with cyclic ether structure such as sugar alcohol; Dihydroxy compounds with cyclic acetal structure such as spirodiol and dioxanediol; 1,2-cyclohexanedicarboxylic acid, 1,3-ring Alicyclic dicarboxylic acids such as hexanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid; malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid , Sebacic acid and other aliphatic dicarboxylic acids. Hereinafter, specific examples of the above-mentioned compound into which a structural unit containing an aromatic ring can be introduced are given. 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(3-methyl-4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethyl Phenyl) 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)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(4- Hydroxyphenyl) hexafluoropropane, 1,1-bis(4-hydroxyphenyl)cyclohexane, bis(4-hydroxyphenyl) sulfite, 2,4'-dihydroxydiphenyl sulfite, bis(4- Hydroxyphenyl) sulfide, bis(4-hydroxy-3-methylphenyl) sulfide, bis(4-hydroxyphenyl) disulfide, 4,4'-dihydroxydiphenyl ether, 4,4' -Dihydroxy-3,3'-dichlorodiphenyl ether and other aromatic bisphenol compounds; 2,2-bis(4-(2-hydroxyethoxy)phenyl)propane, 2,2-bis(4- (2-hydroxypropoxy)phenyl)propane, 1,3-bis(2-hydroxyethoxy)benzene, 4,4'-bis(2-hydroxyethoxy)biphenyl, bis(4-( 2-Hydroxyethoxy) phenyl) dihydroxy compounds such as ether groups bonded to aromatic groups; terephthalic acid, phthalic acid, isophthalic acid, 4,4'-biphenyl Formic acid, 4,4'-diphenyl ether dicarboxylic acid, 4,4'-benzophenone dicarboxylic acid, 4,4'-diphenoxyethane dicarboxylic acid, 4,4'-diphenyl Aromatic dicarboxylic acids such as chrysene dicarboxylic acid and 2,6-naphthalene dicarboxylic acid. Furthermore, the aliphatic dicarboxylic acid and aromatic dicarboxylic acid components exemplified above can be the dicarboxylic acid itself as the raw material of the polyester carbonate. Dicarboxylic acid derivatives such as carboxylic acid esters and dicarboxylic acid halides are used as raw materials.

Regarding the comonomers, 9,9-bis(4-(2-hydroxyethoxy)phenyl)pyridine, 9,9-bis(4-hydroxybenzene) previously known as compounds containing structural units with negative birefringence Dihydroxy compounds having a pyrene ring or dicarboxylic acid compounds having a pyrene ring, such as pyridine, 9,9-bis(4-hydroxy-3-methylphenyl) pyridinium, etc., can also be used in combination with oligomeric pyridinium compounds.

Regarding the resin used in the present invention, among the structural units that can be introduced from the above-mentioned compound having an alicyclic structure, it is particularly preferable to contain a structural unit represented by the following formula (3) as a copolymerization component. [化3]

As the dihydroxy compound into which the structural unit of the above formula (3) can be introduced, spirodiol can be used.

In the resin used in the present invention, the structural unit represented by the above formula (3) preferably contains 5% by mass or more and 90% by mass or less. The upper limit is more preferably 70% by mass or less, particularly preferably 50% by mass or less. The lower limit is more 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 represented by the above formula (3) is more than the above lower limit, sufficient mechanical properties or heat resistance and a low photoelastic coefficient can be obtained. Furthermore, the compatibility with the acrylic resin is improved, and the transparency of the obtained resin composition can be further improved. In addition, the polymerization reaction speed of spirodiol is relatively slow, so by suppressing the content to be below the above upper limit, it is easy to control the polymerization reaction.

The resin used in the present invention preferably further contains a structural unit represented by the following formula (4) as a copolymer component. [化4]

As the dihydroxy compound into which the structural unit represented by the above formula (4) can be introduced, isosorbide (ISB), anhydrous mannitol, and isoidide in the relationship of stereoisomers can be exemplified. These may be used individually by 1 type, and may be used in combination of 2 or more types.

In the resin used in the present invention, the structural unit represented by the above formula (4) preferably contains 5% by mass or more and 90% by mass or less. The upper limit is more preferably 70% by mass or less, particularly preferably 50% by mass or less. The lower limit is more preferably 10% by mass or more, particularly preferably 15% by mass or more. If the content of the structural unit represented by the above formula (4) is more than the above lower limit, sufficient mechanical properties or heat resistance and a low photoelastic coefficient can be obtained. In addition, the structural unit represented by the above formula (4) has the characteristic of high water absorption. Therefore, if the content of the structural unit represented by the above formula (4) is below the above upper limit, the molded body caused by water absorption can be reduced The size change is suppressed within the allowable range.

The resin used in the present invention may further include other structural units. In addition, this structural unit is sometimes referred to as "other structural unit". As a monomer having other structural units, it is more preferable to use 1,4-cyclohexanedimethanol, tricyclodecanedimethanol, and 1,4-cyclohexanedicarboxylic acid (and its derivatives), particularly preferably 1,4-Cyclohexane dimethanol and tricyclodecane dimethanol. The resin containing structural units derived from these monomers has excellent balance of optical properties, heat resistance, and mechanical properties. In addition, since the polymerization reactivity of the diester compound is low, it is preferable not to use diester compounds other than the diester compound containing oligomeric fluoride structural units from the viewpoint of improving reaction efficiency.

The glass transition temperature (Tg) of the resin used in the present invention is preferably 110°C or more and 160°C or less. The upper limit is more preferably 155°C or lower, more preferably 150°C or lower, and particularly preferably 145°C or lower. The lower limit is more preferably 120°C or higher, particularly preferably 130°C or higher. If the glass transition temperature is outside the above range, there is a tendency for heat resistance to deteriorate, which may cause dimensional changes after the film is formed, or the reliability of the quality of the retardation film may deteriorate under the use conditions of the retardation film. On the other hand, if the glass transition temperature is too high, uneven film thickness may occur during film formation, the film may become brittle and the extensibility may deteriorate, and the transparency of the film may be impaired.

Details of the structure and production method of polycarbonate resins and the like are described in, for example, International Publication No. 2015/159928 (above). This description is used in this specification by reference.

C-2-2. Acrylic resin As the acrylic resin, an acrylic resin which is a thermoplastic resin is used. Regarding the monomer as the structural unit of the acrylic resin, for example, the following compounds can be mentioned: methyl methacrylate, methacrylic acid, methyl acrylate, acrylic acid, benzyl (meth)acrylate, and normal (meth)acrylate Butyl ester, isobutyl (meth)acrylate, tertiary butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, tridecane (meth)acrylate Base ester, stearyl (meth)acrylate, glycidyl (meth)acrylate, hydroxypropyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-(meth)acrylate Ethoxy ethyl, cyclohexyl (meth)acrylate, iso(meth)acrylate, nor(meth)acrylate, dicyclopentenyl (meth)acrylate, (meth) Dicyclopentyl acrylate, dicyclopentenoxyethyl (meth)acrylate, methyl tetrahydrofuran (meth)acrylate, acryloyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-(meth)acryloyloxyethyl succinate, 2-(meth)acryloyloxyethyl maleate, 2-(meth)acryloyloxyethyl phthalate, hexahydro 2-(meth)acryloyloxyethyl phthalate, pentamethylpiperidine (meth)acrylate, tetramethylpiperidine (meth)acrylate, dimethylamine (meth)acrylate Ethyl ethyl, diethylamino ethyl (meth)acrylate, cyclopentyl methacrylate, cyclopentyl acrylate, cyclohexyl methacrylate, cyclohexyl acrylate, cycloheptyl methacrylate, acrylic ring Heptyl ester, cyclooctyl methacrylate, cyclooctyl acrylate, cyclododecyl methacrylate, cyclododecyl acrylate. These can be used individually or in combination of 2 or more types. The form of combining two or more monomers can be exemplified by copolymerization of two or more monomers, blending of two or more homopolymers of one monomer, and combinations of these. Furthermore, other monomers (for example, olefin-based monomers, vinyl-based monomers) copolymerizable with these acrylic monomers may be used in combination.

The acrylic resin contains a structural unit derived from methyl methacrylate. The content of the structural unit derived from methyl methacrylate in the acrylic resin is preferably 70% by mass or more and 100% by mass or less. The lower limit is more preferably 80% by mass or more, still more preferably 90% by mass or more, and particularly preferably 95% by mass or more. Within this range, excellent compatibility with the polycarbonate 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. By copolymerizing methyl acrylate, the thermal stability can be improved. By using phenyl (meth)acrylate, benzyl (meth)acrylate, and styrene, the refractive index of acrylic resin can be adjusted, so by mixing the refractive index of the combined resin, the obtained resin composition can be improved The transparency. By using such an acrylic resin, it is possible to obtain an inverse dispersion retardation film with excellent expandability and retardation performance, and a small haze.

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, so that the transparency of the final retardation film (retardation layer) can be improved, and the effect of fully improving the expandability during stretching can be obtained. . Furthermore, the above-mentioned weight average molecular weight is a molecular weight in terms of polystyrene measured by GPC (Gel Permeation Chromatography). In addition, from the viewpoint of compatibility, the acrylic resin preferably does not substantially contain a branch structure. It can be confirmed that the GPC curve of the acrylic resin is unimodal and does not contain a branched structure.

C-2-3. Blending of polycarbonate resins and acrylic resins A polycarbonate resin or the like is blended with an acrylic resin and used as a resin composition for the production method of the retardation film (retardation layer) (the production method will be described in Section C-3 below). It is preferable that polycarbonate resin etc. and acrylic resin can be blended in a molten state. As a method of blending in a molten state, typically, melt kneading using an extruder can be exemplified. The kneading temperature (melted resin temperature) is preferably 200°C to 280°C, more preferably 220°C to 270°C, and still more preferably 230°C to 260°C. If the kneading temperature is within this range, thermal decomposition can be suppressed, and particles of a resin composition uniformly blended with two resins can be obtained. If the temperature of the molten resin in the extruder exceeds 280°C, the resin may be colored and/or thermally decomposed. On the other hand, if the temperature of the molten resin in the extruder is lower than 200°C, the viscosity of the resin is too high and an excessive load is applied to the extruder, or the melting of the resin is insufficient. In addition, as the configuration of the extruder, the configuration of the screw, etc., any appropriate configuration can be adopted. In order to obtain the transparency of the resin that can withstand the use of optical films, it is preferable to use a twin-screw extruder. Furthermore, there is a concern that the remaining low-molecular components in the resin or the low-molecular-weight thermally decomposed components in the extrusion and kneading process may contaminate the cooling roll or the conveying roll during the film forming step or the stretching step. Therefore, in order to remove it, it is preferable To use an extruder with a vacuum vent.

The content of the acrylic resin in the resin composition (the retardation layer as a result) is 0.5% by mass or more and 2.0% by mass or less as described above. 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 weight or less, still more preferably 0.9% by weight or less, and particularly preferably 0.8% by mass or less. In this way, by blending the acrylic resin in the polycarbonate resin in a very limited ratio, the expandability and retardation performance can be significantly increased. Furthermore, haze can be suppressed. This effect is not clear in theory, but is an unexpectedly excellent effect obtained through repeated experiments. Furthermore, if the content of the acrylic resin is too small, the above-mentioned effects may not be obtained. On the other hand, if the content of the acrylic resin is too large, the haze may increase. In addition, compared with the case in the above range, the expandability and phase difference expressivity are also insufficient, and on the contrary, there are many cases where it is lowered.

In order to modify the mechanical properties and/or solvent resistance and other properties of the resin composition, aromatic polycarbonate, aliphatic polycarbonate, aromatic polyester, aliphatic polyester, polyamide, Polystyrene, polyolefin, acrylic acid, amorphous polyolefin, ABS (acrylonitrile-butadiene-styrene, acrylonitrile-butadiene-styrene), AS (acrylonitrile-styrene, acrylonitrile-styrene), polylactic acid, Synthetic resins such as polybutylene succinate, rubber, and combinations of these.

The resin composition may further include additives. Specific examples of additives include heat stabilizers, antioxidants, catalyst deactivators, ultraviolet absorbers, light stabilizers, mold release agents, dyes/pigments, impact modifiers, antistatic agents, slip agents, and lubricants. Agents, plasticizers, compatibilizers, nucleating agents, flame retardants, inorganic fillers, foaming agents. The type, amount, combination, content, etc. of the additives contained in the resin composition can be appropriately set according to the purpose.

C-3. Formation method of retardation layer The retardation layer can be obtained by forming a film from the resin composition described in the above item C-2, and then stretching the film. As a method of forming a film from the resin composition, any appropriate forming method can be adopted. Specific examples include compression molding, transfer molding, injection molding, extrusion molding, blow molding, powder molding, FRP (Fiber Reinforced Plastics) molding, and casting coating. (For example, casting method), calendering method, hot pressing method, etc. Among them, the extrusion molding method or the casting coating method that can improve the smoothness of the obtained film and obtain good optical uniformity is preferable. The casting coating method may cause problems due to residual solvents, so the extrusion molding method is particularly preferred. In the extrusion molding method, from the viewpoint of the productivity of the film or the ease of subsequent stretching treatment, it is better to use Melt extrusion molding method of T-die head. The molding conditions can be appropriately set according to the composition or type of the resin used, the characteristics required for the retardation layer, and the like. In this way, a resin film containing polycarbonate resin and the like and acrylic resin can be obtained.

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 following stretching conditions, and the like. It is preferably 50 μm to 300 μm.

Any appropriate stretching method and stretching conditions (for example, stretching temperature, stretching magnification, stretching direction) can be used for the above-mentioned stretching. Specifically, various extension methods such as free end extension, fixed end extension, free end contraction, and fixed end contraction can be used alone, or simultaneously or successively. Regarding the extension direction, it may be performed in various directions or dimensions such as the length direction, the width direction, the thickness direction, and the oblique direction.

By appropriately selecting the above-mentioned stretching method and stretching conditions, a retardation layer having the above-mentioned required optical characteristics (for example, refractive index characteristics, in-plane retardation, and Nz coefficient) can be obtained.

In one embodiment, the stretching temperature of the film is a temperature equal to or lower than the glass transition temperature (Tg) of a polycarbonate resin or the like. Generally, when a film of a polycarbonate resin or the like is stretched, the film is in a glass state at a temperature below Tg, so that it cannot be stretched substantially. According to the resin film used in the embodiment of the present invention, by blending a small amount of acrylic resin (typically polymethyl methacrylate), it is possible to achieve extension below Tg without substantially changing the Tg of polycarbonate resin etc. . Furthermore, although it is not clear in theory, by stretching at or below Tg, it is possible to realize an inverse dispersion retardation film (retardation layer) that is excellent in expandability and retardation performance, and has a small haze. Specifically, the elongation temperature is preferably Tg to Tg-10°C, more preferably Tg to Tg-8°C, and still more preferably Tg to Tg-5°C. Furthermore, the above-mentioned film can be stretched appropriately even at a temperature higher than Tg, such as Tg+5°C at the highest temperature, for example, Tg+2°C or so.

The stretched film obtained in the above-mentioned manner is preferably subjected to heat treatment for heating at a temperature of 105° C. or higher for 2 minutes or longer. By performing heat treatment, a retardation layer having the aforementioned desired shrinkage rate can be formed. The heating temperature is preferably 105°C to 140°C, more preferably 110°C to 130°C, and still 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 still more preferably 5 minutes to 60 minutes.

If necessary, stretched film can be used for relaxation treatment. Thereby, the stress generated by the extension can be alleviated, and the retardation layer having the aforementioned required shrinkage rate can be formed. As the relaxation treatment conditions, any appropriate conditions can be adopted. For example, the stretched film is shrunk at a predetermined relaxation temperature and a predetermined relaxation rate (shrinkage rate) in the extension direction. The relaxation temperature is preferably 60°C to 150°C. The relaxation rate is preferably 3% to 6%. In the case of the relaxation treatment, the relaxation treatment is typically carried out before the above-mentioned heat treatment.

In the above manner, a retardation film constituting the retardation layer can be obtained.

D. The first adhesive layer and the second adhesive layer D-1. The characteristics of the first adhesive layer and/or the second adhesive layer 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, and still more preferably 390 μm or more, particularly preferably 420 μm or more. The upper limit of the paste offset can be, for example, 600 μm. In this way, the polarizing element and the retardation layer are bonded by using an adhesive with a large amount of paste offset, so as to control the shrinkage rate of the retardation layer in the direction of the retardation axis and control the following second adhesive layer The synergistic effect of the effect obtained by the creep value can realize the polarizing plate with the retardation layer and the adhesive layer in which the unevenness of the retardation can be suppressed in a high temperature environment. Furthermore, in this specification, the so-called "paste offset" refers to the overflow of the adhesive layer that overflows from the end surface of the polarizing element and the retardation layer after the heating test in the polarizing plate with the retardation layer and the adhesive layer The length of the largest part.

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, still more preferably 60 μm or more, particularly preferably 100 μm or more, especially Preferably, it is 120 μm or more. The upper limit of the creep value may be 300 μm, for example. In this way, the polarizing plate with the retardation layer and the adhesive layer is attached to the image display unit by using an adhesive with a larger creep value, so as to control the shrinkage rate of the retardation layer in the direction of the late axis. The synergistic effect of the effect of controlling the paste offset of the first adhesive layer described above can realize an image display device in which color unevenness can be suppressed in a high-temperature environment. The creep value can be measured, for example, by the following procedure: a test sample cut from the adhesive sheet is attached to a support plate with a bonding surface of 10 mm×10 mm. With the support plate attached with the test sample fixed, apply a load of 500 gf below the plumb. Measure the deflection of the self-supporting plate after 1 second and 3600 seconds after the load is applied, and set them as Cr ₁ and Cr _{3600 respectively} . Let ΔCr calculated by the following formula based on Cr ₁ and Cr _{3600 be the creep value.} In addition, the creep value in this specification is the value when the thickness of the adhesive layer is converted to 20 μm. ΔCr＝Cr ₃₆₀₀ －Cr ₁

The storage elastic modulus at 85°C of the first adhesive layer and/or the second adhesive layer is preferably 1.0×10 ⁴ Pa or more, preferably 2.0×10 ⁴ Pa or more, more preferably 5.0×10 ⁴ Pa Above, it is more preferably 1.0×10 ⁵ Pa or more. If the storage elastic modulus is within this range, the required paste offset and/or creep value mentioned above can be easily achieved. On the other hand, the storage elastic modulus is 3.0×10 ⁶ Pa or less, for example.

The thickness of the first adhesive layer is preferably 2 μm-50 μm, more preferably 3 μm-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 thickness of the first adhesive layer and the second adhesive layer are within this range, the synergistic effect with the effect of controlling the paste offset and creep value can achieve the same phase difference in a high-temperature environment. The polarizing plate with the retardation layer and the adhesive layer can be suppressed, and the image display device with suppressed color unevenness under high temperature environment can be realized.

D-2. The constituent materials of the first adhesive layer and the second adhesive layer Regarding the first adhesive layer and the second adhesive layer, as long as the first adhesive layer has the above-mentioned required paste offset and the second adhesive layer has the above-mentioned required creep value, any suitable structure can be adopted. The first adhesive layer and the second adhesive layer may include the same adhesive or different adhesives. Hereinafter, the first adhesive layer and the second adhesive layer are collectively used as the adhesive layer, and the constituent materials will be described. By adjusting the composition of the adhesive constituting the adhesive layer (for example, the type of base polymer (polarity, Tg, flexibility), molecular weight), the cross-linking structure (for example, the type of cross-linking agent, the distance between cross-linking points ( The molecular weight between cross-linking points), cross-linking density), etc., can control the paste offset and/or creep value.

D-2-1. Basic polymer The adhesive layer is typically formed of an adhesive composition containing a (meth)acrylic polymer, a urethane polymer, a silicone polymer, or a rubber polymer as a base polymer. When a (meth)acrylic polymer is used as the base polymer, the adhesive layer is formed of, for example, an adhesive composition containing (meth)acrylic polymer (A). The (meth)acrylic polymer (A) contains an alkyl (meth)acrylate as a main component.

＜(Meth)acrylic polymer (A)＞ The (meth)acrylic polymer (A) contains an alkyl (meth)acrylate as a main component as described above. From the viewpoint of improving the adhesiveness of the adhesive layer, the alkyl (meth)acrylate is preferably 50% by weight or more in all monomer components forming the (meth)acrylic polymer (A). The remainder of the monomers other than the alkyl (meth)acrylate can be arbitrarily set. In addition, (meth)acrylate means acrylate and/or methacrylate.

As the (meth)acrylic acid alkyl ester constituting the main skeleton of the (meth)acrylic polymer (A), a linear or branched alkyl group having 1 to 18 carbon atoms (methyl) can be mentioned. Alkyl acrylate. As the alkyl group, for example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, hexyl, cyclohexyl, heptyl, 2-ethylhexyl, isooctyl, nonyl Alkyl, decyl, isodecyl, dodecyl, isomyristyl, lauryl, tridecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, etc. The alkyl (meth)acrylates can be used alone or in combination. The average carbon number of the alkyl group is preferably 3-10.

In the (meth)acrylic polymer (A), in addition to containing (meth)acrylic acid alkyl ester as a monomer component, carboxyl group-containing monomers (a1), hydroxyl group-containing monomers (a2), etc. may also be included. Comonomers are used as monomer components. The comonomer can be used alone or in combination.

The carboxyl group-containing monomer (a1) is a compound containing a carboxyl group in its structure and a polymerizable unsaturated double bond such as a (meth)acryloyl group and a vinyl group. As a monomer containing a carboxyl group, for example, (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid Wait. Among them, from the viewpoints of copolymerization, price, and improvement of the adhesive properties of the adhesive layer, acrylic is preferred.

When using a carboxyl group-containing monomer (a1) as the monomer component, the content of the carboxyl group-containing monomer (a1) in all monomer components forming the (meth)acrylic polymer (A) is usually 0.01 More than 10% by weight.

The hydroxyl group-containing monomer (a2) is a compound containing a hydroxyl group in its structure and a polymerizable unsaturated double bond such as a (meth)acryloyl group and a vinyl group. Examples of monomers containing hydroxyl groups include: 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and (meth)acrylic acid. Hydroxyalkyl (meth)acrylates such as 6-hydroxyhexyl ester, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, etc.; acrylic acid (4-Hydroxymethylcyclohexyl) methyl ester and the like. Among them, from the viewpoint of improving the durability of the adhesive layer, 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are preferred, and (meth)acrylic acid is more preferred. 4-hydroxybutyl ester.

When using a hydroxyl-containing monomer (a2) as the monomer component, the content of the hydroxyl-containing monomer (a2) in all monomer components forming the (meth)acrylic polymer (A) is usually 0.01 More than 10% by weight.

The (meth)acrylic polymer (A) preferably contains, as a monomer component, a monomer having a homopolymer with a glass transition temperature of 0°C or higher and having an unsaturated carbon double bond. As the monomer (a3) having an unsaturated carbon double bond whose glass transition temperature of the homopolymer is 0°C or higher, alkyl (meth)acrylate monomers and (meth)acrylic acid can be mentioned. Monomer (a3) is preferably a monomer having an unsaturated carbon double bond with a homopolymer having a glass transition temperature of 20°C or higher, and more preferably a homopolymer having an unsaturated carbon double bond with a glass transition temperature of 40°C or higher The monomer of the bond.

The ratio of the monomer (a3) contained in the (meth)acrylic polymer (A) is not particularly limited. The content is usually 0.1% by weight to 40% by weight, more preferably 1% by weight to 30% by weight. In addition, the content is the total content when two or more monomers (a3) are used in combination.

The monomer (a3) may, for example, be methyl acrylate (Tg: 8°C), methyl methacrylate (Tg: 105°C), ethyl methacrylate (Tg: 65°C), n-propyl acrylate (Tg: 3°C), n-propyl methacrylate (Tg: 35°C), n-pentyl acrylate (Tg: 22°C), n-tetradecyl acrylate (Tg: 24°C), n-hexadecane acrylate Base ester (Tg: 35°C), n-hexadecyl methacrylate (Tg: 15°C), n-octadecyl acrylate (Tg: 30°C) and n-octadecyl methacrylate (Tg ：38℃) and other linear alkyl (meth)acrylates; tertiary butyl acrylate (Tg: 43℃), tertiary butyl methacrylate (Tg: 48℃), isopropyl methacrylate (Tg : 81°C) and branched chain (meth)acrylate alkyl esters such as isobutyl methacrylate (Tg: 48°C); cyclohexyl acrylate (Tg: 19°C), cyclohexyl methacrylate (Tg: 65 ℃), cyclic alkyl acrylates such as iso(meth)acrylate (Tg: 94°C) and iso(meth)acrylate (Tg: 180°C); acrylic acid (Tg: 106°C) and the like. These can be used alone or in combination.

When the adhesive composition contains the following crosslinking agent, the comonomer becomes a reaction point with the crosslinking agent. The carboxyl group-containing monomers and the hydroxyl group-containing monomers are highly reactive with the intermolecular crosslinking agent, so they can be preferably used to improve the cohesiveness or heat resistance of the obtained adhesive layer. In addition, a monomer containing a carboxyl group is preferable in terms of both durability and secondary workability, and a monomer containing a hydroxyl group is preferable in terms of improving secondary workability.

As the monomer component, other comonomers (a4) can be further used. The other comonomer (a4) has, for example, a polymerizable functional group having an unsaturated double bond such as a (meth)acryloyl group or a vinyl group. By using other comonomers (a4), the adhesion and heat resistance of the adhesive layer can be improved. The other comonomers (a4) can be used alone or in combination.

By using monomers containing amine groups and monomers containing amide groups as other comonomers (a4), the adhesiveness of the adhesive layer can be improved. The monomer containing an amine group is, for example, N,N-dimethylaminoethyl (meth)acrylate and N,N-dimethylaminopropyl (meth)acrylate. Monomers containing amide groups are, 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-methylol(meth)acrylamide, N-methyl(meth)acrylamide, N-hexyl(meth)acrylamide, )Acrylamide, N-hydroxymethyl-N-propane (meth)acrylamide, aminomethyl(meth)acrylamide, aminoethyl(meth)acrylamide, mercaptomethyl( Acrylamine-based monomers such as meth)acrylamide and mercaptoethyl (meth)acrylamide; N-(meth)acrylamide, N-(meth)acrylpiperidine, N- (Meth) acryloylpyrrolidine and other N-acryloyl heterocyclic monomers; N-vinylpyrrolidone, N-vinyl-ε-caprolactam and other N-vinyl-containing internal amines monomer.

The other comonomer (a4) may be a multifunctional monomer. By using multifunctional monomers, the gel fraction of the adhesive layer can be adjusted or the cohesive force can be controlled. Multifunctional monomers are, for example, hexanediol di(meth)acrylate (1,6-hexanediol di(meth)acrylate), butanediol di(meth)acrylate, (poly)ethylene Glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylic acid Ester, dipentaerythritol hexa(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, allyl(meth)acrylate, (meth) ) Multifunctional acrylates such as vinyl acrylate, epoxy acrylate, polyester acrylate, and urethane acrylate; and divinylbenzene. The multifunctional acrylate is preferably 1,6-hexanediol diacrylate and dipentaerythritol hexa(meth)acrylate.

Other comonomers (a4) in addition to the above, for example: 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, methoxytriethylene glycol (meth) Base) acrylate, 3-methoxypropyl (meth)acrylate, 3-ethoxypropyl (meth)acrylate, 4-methoxybutyl (meth)acrylate, (meth)acrylate 4 -Alkoxyalkyl (meth)acrylates such as ethoxybutyl ester; Cyclic polymerizable monomers such as methyl 2-(allyloxymeth)acrylate; Glycidyl (meth)acrylate, ( Monomers containing epoxy groups such as methyl glycidyl methacrylate; monomers containing sulfonic acid groups such as sodium vinyl sulfonate; monomers containing phosphoric acid groups; cyclopentyl (meth)acrylate, (formaldehyde) (Meth)acrylates having alicyclic hydrocarbon groups such as cyclohexyl acrylate, iso(meth)acrylate, etc.; (meth) phenyl acrylate, (meth) phenoxy ethyl acrylate, ( (Meth)acrylates with aromatic hydrocarbon groups such as benzyl methacrylate; vinyl esters such as vinyl acetate and vinyl propionate; aromatic vinyl compounds such as styrene and vinyl toluene; ethylene, propylene, butylene Alkenes or dienes such as dienes, isoprene, and isobutylene; vinyl ethers such as vinyl alkyl ethers; vinyl chloride.

The content of the other comonomer (a4) in the (meth)acrylic polymer is preferably 20% by mass or less, more preferably 10% by mass or less, still more preferably 8% by mass or less, and particularly preferably 5% by mass the following.

The weight average molecular weight Mw of the (meth)acrylic polymer (A) is, for example, 200,000 to 3 million, preferably 1 million to 2.5 million, more preferably 1.2 million to 2.5 million. If the weight average molecular weight Mw is in such a range, an adhesive layer excellent in durability (especially heat resistance) can be obtained. If the weight average molecular weight Mw exceeds 3 million, the viscosity may increase and/or gelation may occur during polymer polymerization.

D-2-2. Silane coupling agent containing reactive functional groups The adhesive composition may include a silane coupling agent containing reactive functional groups. The reactive functional group of the silane coupling agent containing a reactive functional group is typically a functional group other than an acid anhydride group. Examples of functional groups other than acid anhydride groups include epoxy groups, mercapto groups, amine groups, isocyanuric groups, isocyanuric acid groups, vinyl groups, styryl groups, acetylacetamide groups, ureido groups, and thiourea groups. , (Meth)acryloyl group, heterocyclic group and combinations of these. Silane coupling agents containing reactive functional groups can be used alone or in combination.

When the silane coupling agent containing the reactive functional group is formulated in the adhesive composition, the compounding amount of the silane coupling agent containing the reactive functional group is relative to 100 parts by weight of the (meth)acrylic polymer (A), It is usually 0.001 part by weight or more and 5 parts by weight or less.

D-2-3. Crosslinking agent The adhesive composition may contain a crosslinking agent. As a crosslinking agent, an organic crosslinking agent, a polyfunctional metal chelate compound, etc. can be used. As an organic type crosslinking agent, an isocyanate type crosslinking agent, a peroxide type crosslinking agent, an epoxy type crosslinking agent, and an imine type crosslinking agent are mentioned, for example. Multifunctional metal chelate is formed by covalent bonding or coordination bonding of multivalent metal and organic compound. When the adhesive composition is a radiation curable type, a multifunctional monomer can be used as a crosslinking agent. The crosslinking agent can be used alone or in combination.

When a crosslinking agent is blended in the adhesive composition, the blending amount of the crosslinking agent is usually 0.01 part by weight or more and 15 parts by weight or less with respect to 100 parts by weight of the (meth)acrylic polymer (A).

When the isocyanate-based crosslinking agent is blended in the adhesive composition, the blending amount of the isocyanate-based crosslinking agent is usually 0.01 part by weight or more and 15 parts by weight or less with respect to 100 parts by weight of the (meth)acrylic polymer.

When the peroxide is blended in the adhesive composition, the blending amount of the peroxide is usually 0.01 part by weight or more and 2 parts by weight or less with respect to 100 parts by weight of the (meth)acrylic polymer. If it is in such a range, it is easy to adjust processability, crosslinking stability, etc.

D-2-4. Additives The adhesive composition may contain (meth)acrylic oligomers and/or ionic compounds. In addition, the adhesive composition may contain additives. Specific examples of additives include: powders such as colorants and pigments, dyes, surfactants, plasticizers, adhesiveness imparting agents, surface lubricants, leveling agents, softeners, antioxidants, and anti-aging agents , Light stabilizers, UV absorbers, polymerization inhibitors, inorganic or organic fillers, metal powders, particles, foils. In addition, within a controllable range, a redox system added with a reducing agent can be used. The type, quantity, combination, content, etc. of the additives can be appropriately set according to the purpose. With respect to 100 parts by weight of the (meth)acrylic polymer (A), the content of the additive is preferably 5 parts by weight or less, more preferably 3 parts by weight or less, and still more preferably 1 part by weight or less.

E. Image display device The polarizing plate with retardation layer and adhesive layer described in the above items A to D can be applied to an image display device. Therefore, the embodiment of the present invention also includes an image display device using the polarizing plate with a retardation layer and an adhesive layer. As a representative example of an image display device, a liquid crystal display device and an organic EL display device can be cited. The image display device of the embodiment of the present invention is typically provided with the polarizing plate with the retardation layer and the adhesive layer described in the above items A to D on the viewing side. Example

Hereinafter, the present invention will be specifically described with examples, but the present invention is not limited by these examples. In addition, the measuring method of each characteristic is as follows.

(1) Paste offset The polarizing plates with retardation layer and adhesive layer obtained in the examples and comparative examples were cut into predetermined sizes (M size or T size in Table 1 below), and used as test samples. The test sample was subjected to a heating test at 85° C. and 500 hours, and the overflow amount of the first adhesive layer overflowing from the end surface of the polarizing element and the retardation layer after the heating test was observed and measured using an objective lens (20 times). The length of the most overflowing part of the first adhesive layer is used as the paste offset. When observing, adjust so that the transmitted light is 0 (zero) and the reflected light is observed. (2) Creep value The polarizing plates with retardation layer and adhesive layer obtained in the examples and comparative examples were cut into a size of 10 mm×30 mm and used as test samples. The 10 mm×10 mm upper end of the test sample was attached to a SUS (Steel Use Stainless) plate through the second adhesive layer, and a load of 500 gf was applied to the lower end of the test sample vertically downward. The deviation between the test sample and the SUS plate after 1 second and 3600 seconds after the load was applied was measured and set to Cr ₁ and Cr _{3600 respectively} . Let ΔCr calculated by the following formula based on Cr ₁ and Cr _{3600 be the creep value.} ΔCr=Cr ₃₆₀₀ －Cr ₁ (3) Color unevenness Cut the polarizing plate with retardation layer and adhesive layer obtained in the Examples and Comparative Examples into specified sizes (M size or T size in Table 1 below), It was bonded to the glass plate via the second adhesive layer as a test sample. The test sample heated at 85°C for 500 hours is placed on a reflector (DMS vapor-deposited film manufactured by Toray Film Processing Co., Ltd.), and a spectrophotometer (manufactured by Konica Minolta, product name "CM -2600d”) to measure the reflection hues a ^* _C and b ^* _C at the center of the sample and the reflection hues a ^* _E and b ^* _E at the end of the sample. The Δab obtained by the following formula was used as an index of color unevenness. The smaller the Δab, the better the color unevenness. Δab={(a ^* _E-a ^* _C ) ² + (b ^* _E- b ^* _C ) ² } ^1/2

・ISB：異山梨糖醇[Roquette Freres公司製造] ・SPG：螺二醇[三菱瓦斯化學股份有限公司製造] ・DPC：碳酸二苯酯[三菱化學股份有限公司製造][Abbreviation of the compound] The abbreviation of the compound used in the following production examples is as follows.・BPFM: Bis[9-(2-phenoxycarbonylethyl)茀-9-yl]methane was synthesized by the method described in Japanese Patent Laid-Open No. 2015-25111. [化5]

・ISB: Isosorbide [manufactured by Roquette Freres] ・SPG: Spirodiol [manufactured by Mitsubishi Gas Chemical Co., Ltd.] ・DPC: Diphenyl carbonate [manufactured by Mitsubishi Chemical Co., Ltd.]

[Production Example 1: Production of retardation film constituting retardation layer] The polymerization was carried out using a batch polymerization apparatus including a vertical stirring reactor 2 equipped with a stirring blade and a reflux cooler. Add 30.31 parts by mass (0.047 mol) of BPFM, 39.94 parts by mass (0.273 mol) of ISB, 30.20 parts by mass (0.099 mol) of SPG, 69.67 parts by mass (0.325 mol) of DPC, and 7.88 parts by mass of DPC as one of the catalysts. ×10 ^-4 parts by mass (4.47 × 10 ^-6 mol). After the inside of the reactor was replaced with nitrogen under reduced pressure, it was heated with a heating medium, and when the internal temperature reached 100°C, stirring was started. 40 minutes after the temperature rise started, the internal temperature was brought to 220°C, and the pressure was started while controlling to maintain the temperature. After reaching 220°C, it was brought to 13.3 kPa in 90 minutes. The phenol vapor produced by the polymerization reaction is introduced to a reflux cooler at 110°C, a certain amount of monomer components contained in the phenol vapor is returned to the reactor, and the uncondensed phenol vapor is introduced to 45°C for condensation And recycled. Nitrogen gas was introduced into the first reactor, and after the pressure was temporarily restored to atmospheric pressure, the oligomerized reaction liquid in the first reactor was transferred to the second reactor. Then, the temperature rise and pressure reduction in the second reactor were started, and the internal temperature was set to 240° C. and the pressure was set to 20 kPa over 40 minutes. Thereafter, while reducing the pressure, polymerization is carried out until it becomes a predetermined stirring power. When reaching the specified power, nitrogen is introduced into the reactor for re-pressing, the resulting polyester carbonate is extruded into water, and the strands are cut to obtain pellets. This resin is called "PC1". The ratio of the structural unit derived from each monomer is BPFM/ISB/SPG/DPC=21.5/39.4/30.0/9.1% by mass. The reduction viscosity of PC1 is 0.46 dL/g, Mw is 48,000, refractive index n _D is 1.526, melt viscosity is 2480 Pa·s, glass transition temperature is 139°C, photoelastic coefficient is 9×10 ^-12 [m ² /N ], the wavelength dispersion Re(450)/Re(550) is 0.85.

Dianal BR80 (manufactured by Mitsubishi Chemical Corporation) was used as the acrylic resin, and the obtained polyester carbonate was extruded and kneaded. A quantitative feeder was used to mix polycarbonate pellets (99.5 parts by mass) and BR80 powder (0.5 parts by mass) into a twin-screw extruder TEX30HSS manufactured by Japan Steel Works Co., Ltd. The temperature of the cylinder of the extruder was set to 250°C, and the extrusion was carried out with a throughput of 12 kg/hr and a screw speed of 120 rpm. In addition, the extruder is equipped with a vacuum vent, and the molten resin is extruded while depressurizing and evaporating. After drying the pellets of the resin composition obtained in this way at 100°C for 6 hours or more, use a single-screw extruder (manufactured by Isuzu Kakoki, screw diameter 25 mm, cylinder setting temperature: 250°C), T The film-making device of the mold head (width 300 mm, set temperature: 220°C), cooling roll (set temperature: 120～130°C), and coiler, with a length of 3 m, width of 200 mm, and thickness of 100 μm. Strip unstretched film. The long unstretched film was stretched at a stretching temperature Tg and a stretching magnification of 2.4 times. The obtained stretched film was subjected to a relaxation treatment (the relaxation temperature was 130°C, and the relaxation rate was 4.5%), and then subjected to a heat treatment at 125°C for 2 minutes.

In this way, the retardation film R1 constituting the retardation layer is obtained. When the retardation film R1 was heated at 125°C for 180 minutes, the shrinkage rate in the slow axis direction was 2.92%. In addition, the retardation film R1 showed a refractive index characteristic of nx>ny>nz, Re (550) was 145 nm, and Re (450)/Re (550) was 0.85.

[Manufacturing Example 2: Production of retardation film constituting retardation layer] The retardation film R2 was obtained in the same manner as in Manufacturing Example 1 except that the relaxation treatment and the heating treatment were not performed. When the retardation film R2 was heated at 125° C. for 180 minutes, the shrinkage rate in the slow axis direction was 4.54%. In addition, the retardation film R2 shows a refractive index characteristic of nx>ny>nz, Re(550) is 145 nm, and Re(450)/Re(550) is 0.85.

[Manufacturing Example 3: Preparation of Adhesive] (Preparation of acrylic polymer A1) 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 stirring blade, a thermometer, a nitrogen introduction tube, and a cooler. Furthermore, with respect to 100 parts of the monomer mixture, 0.1 part of 2,2'-azobisisobutyronitrile as a polymerization initiator was added together with 100 parts of ethyl acetate, and nitrogen was introduced while slowly stirring the mixture to perform nitrogen substitution. , Keep the liquid temperature in the flask at around 55°C, and perform polymerization reaction for 8 hours to prepare a solution of acrylic polymer A1 with a weight average molecular weight (Mw) of 1.8 million and Mw/Mn=4.8.

(Preparation of adhesive) With respect to 100 parts of the solid content of the acrylic polymer A1 solution, 0.02 parts of trimethylolpropane/xylylene diisocyanate adduct (manufactured by Tosoh Corporation, trade name "Takenate D110N"), peroxide Crosslinking agent (manufactured by Nippon Oil & Fat Co., Ltd., trade name "Nyper BMT") 0.3 parts and epoxy-containing silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBM-403") 0.2 parts, to obtain adhesion剂PSA1.

[Manufacturing Example 4: Preparation of Adhesive] The adhesive PSA2 was obtained in the same manner as in Production Example 3 except that the compounding amount of D110N was changed to 0.1 part.

[Manufacturing Example 5: Preparation of Adhesive] (Preparation of acrylic polymer A2) Except for using a monomer mixture containing 94.9 parts of butyl acrylate, 0.1 part of 2-hydroxyethyl acrylate, and 5 parts of acrylic acid, in the same manner as in Production Example 3, an acrylic system with Mw of 2.3 million and Mw/Mn=3.9 was prepared. Solution of polymer A2.

(Preparation of adhesive) With respect to 100 parts of the solid content of the acrylic polymer A2 solution, 0.6 part of trimethylolpropane/toluene diisocyanate adduct (manufactured by Tosoh Corporation, trade name "Coronate L"), peroxide cross-linked 0.2 parts of the agent (manufactured by Nippon Oil & Fat 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") to obtain adhesive PSA3.

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

(Preparation of adhesive) With respect to 100 parts of the solid content of the acrylic polymer A3 solution, 0.1 part of trimethylolpropane/toluene diisocyanate adduct (manufactured by Tosoh Corporation, trade name "Coronate L"), peroxide cross-linked 0.3 parts of Nippon Oil & Fat Co., Ltd., brand name "Nyper BMT") and 0.2 parts of epoxy-containing silane coupling agent (Shin-Etsu Chemical Co., Ltd. brand name "KBM-403") to obtain adhesive PSA4.

[Manufacturing Example 7: Preparation of Adhesive] (Preparation of acrylic polymer A4) Except for using a monomer mixture containing 82.1 parts of butyl acrylate, 13 parts of benzyl acrylate, 0.1 part of 4-hydroxybutyl acrylate, and 4.8 parts of acrylic acid, in the same manner as in Production Example 3, an acrylic system with Mw of 2.2 million was prepared. Solution of polymer A4.

(Preparation of adhesive) With respect to 100 parts of the solid content of the acrylic polymer A4 solution, 0.5 part of polyether compound with reactive silyl group (manufactured by Kaneka, trade name "Silyl SAT10"), trimethylolpropane/toluene diisocyanate is blended 0.45 parts of the adduct (manufactured by Tosoh Corporation, trade name "Coronate L") and 0.1 part of peroxide crosslinking agent (benzyl peroxide) to obtain adhesive PSA5.

[Manufacturing Example 8: Manufacturing of Polarizing Plate] (Production of polarizing element) A long roll of 30 μm polyvinyl alcohol (PVA) resin film (manufactured by Kuraray Co., Ltd., product name "PE3000") is made into a long roll with a roll stretcher that is 5.9 times the length direction Perform uniaxial stretching in the direction, simultaneously perform swelling, dyeing, crosslinking, and washing treatments, and finally perform a drying treatment to produce a polarizing element with a thickness of 12 μm. Specifically, the swelling treatment is to extend 2.2 times while using pure water at 20°C. Secondly, the dyeing process is carried out in an aqueous solution at 30°C with a weight ratio of iodine to potassium iodide adjusted to 1:7 so that the monomer transmittance of the obtained polarizing element becomes 45.0%, and the surface is stretched by 1.4 times. . Furthermore, the cross-linking treatment adopts a two-stage cross-linking treatment. The first-stage cross-linking treatment is carried out in an aqueous solution in which boric acid and potassium iodide are dissolved at 40° C. and stretches 1.2 times. The content of boric acid in the aqueous solution of the crosslinking treatment in the first stage was 5.0% by weight, and the content of potassium iodide was 3.0% by weight. The second stage of cross-linking treatment is to extend 1.6 times while treating in an aqueous solution containing boric acid and potassium iodide at 65°C. The content of boric acid in the aqueous solution of the crosslinking treatment in the second stage was 4.3% by weight, and the content of potassium iodide was 5.0% by weight. In addition, the washing treatment was performed with a potassium iodide aqueous solution at 20°C. The potassium iodide content of the aqueous solution of the washing treatment was set to 2.6% by weight. Finally, the drying process was dried at 70°C for 5 minutes to obtain a polarizing element.

(Making of polarizing plate) A triacetyl cellulose film (40 μm thick, manufactured by Konica Minolta, trade name "KC4UYW") was attached to one side of the above-mentioned polarizing element via a polyvinyl alcohol-based adhesive to obtain a protective layer/ The polarizing plate P1 of the composition of the polarizing element.

[Manufacturing Example 9: Manufacturing of Polarizing Plate] (Production of polarizing element) As a thermoplastic resin substrate, a long strip of amorphous poly(ethylene terephthalate) film with a Tg of about 75°C (thickness: 100 μm) is used for one side of the resin substrate. Corona treatment. PVA mixed with polyvinyl alcohol (polymerization degree 4200, saponification degree 99.2 mol%) and acetyl acetyl modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "Gohsefimer") at a ratio of 9:1 13 parts by weight of potassium iodide was added to 100 parts by weight of the resin, and the resultant was dissolved in water to prepare a PVA aqueous solution (coating liquid). The above-mentioned PVA aqueous solution was applied to 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 to produce a laminate. The obtained laminate was uniaxially stretched to 2.4 times in the longitudinal direction (length direction) in an oven at 130°C (air-assisted stretching treatment). Then, the layered body was immersed in an insoluble bath (a boric acid aqueous solution obtained by blending 4 parts by weight of boric acid with respect to 100 parts by weight of water) at a liquid temperature of 40°C for 30 seconds (insoluble treatment). Then, while adjusting the concentration so that the monomer transmittance (Ts) of the polarizing element finally obtained becomes the desired value, the concentration is adjusted in a dyeing bath at a liquid temperature of 30°C (with respect to 100 parts by weight of water, with a weight of 1:7 It is immersed in an iodine aqueous solution obtained by blending iodine and potassium iodide for 60 seconds (dyeing treatment). Then, it was immersed in a crosslinking bath (a boric acid aqueous solution obtained by blending 3 parts by weight of potassium iodide and 5 parts by weight of boric acid with respect to 100 parts by weight of water) at a liquid temperature of 40°C for 30 seconds (crosslinking treatment). After that, while immersing the layered body in a boric acid aqueous solution (boric acid concentration of 4% by weight and potassium iodide concentration of 5% by weight) at a liquid temperature of 70°C, the total length between the rollers with different peripheral speeds in the longitudinal direction (length direction) Uniaxial stretching (underwater stretching treatment) is performed so that the stretching magnification becomes 5.5 times. After that, the layered body was immersed in a washing bath with a liquid temperature of 20°C (an aqueous solution obtained by mixing 4 parts by weight of potassium iodide with respect to 100 parts by weight of water) (washing treatment). After that, while drying in an oven maintained at about 90°C, it was brought into contact with a heating roller made of SUS whose surface temperature was maintained at about 75°C (drying shrinkage treatment). In this way, a polarizing element with a thickness of about 5 μm is formed on the resin substrate to obtain a polarizing plate having a resin substrate/polarizing element composition.

(Making of polarizing plate) A cycloolefin-based film (ZF-12, 23 μm, manufactured by Zeon Corporation, Japan) as a protective layer was bonded to the surface of the obtained polarizing element (the surface opposite to the resin base material) via an ultraviolet curable adhesive. Specifically, it is applied so that the total thickness of the curable adhesive becomes approximately 1.0 μm, and is bonded using a roller press. After that, UV rays are irradiated from the cycloolefin-based film side to harden the adhesive. Then, the resin substrate was peeled off to obtain a polarizing plate P2 having a cycloolefin-based film (protective layer)/polarizing element configuration.

[Examples 1 to 5 and Comparative Examples 1 to 8] The polarizing plate, the retardation film (retardation layer), and the adhesive (the first adhesive layer and the second adhesive layer) were combined as shown in Table 1 to produce a polarizing plate with a retardation layer and an adhesive layer. Here, the polarizing plate and the retardation layer (retardation film) are attached so that the absorption axis of the polarizing element and the retardation axis of the retardation film form an angle of 45°. The obtained polarizing plate with retardation layer and adhesive layer was used for the evaluation of the above-mentioned color unevenness. The results are shown in Table 1 together 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. In addition, the "M" in the "Size" column of Table 1 means the size of 77.4 mm × 162.3 mm, and the "T" means the size of 159.5 mm × 244.5 mm.

[Table 1] Example 1 Example 2 Example 3 Example 4 Example 5 Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4 Comparative example 5 Comparative example 6 Comparative example 7 Comparative example 8 Polarizing plate P1 P1 P1 P1 P1 P2 P1 P1 P1 P1 P1 P1 P1 Adhesive layer 1 PSA1 PSA1 PSA1 PSA1 PSA1 PSA1 PSA5 PSA5 PSA1 PSA1 PSA1 PSA1 PSA5 Retardation layer R1 R1 R1 R1 R1 R2 R1 R2 R2 R2 R2 R2 R1 2nd adhesive layer PSA4 PSA1 PSA2 PSA3 PSA1 PSA1 PSA2 PSA2 PSA4 PSA1 PSA2 PSA3 PSA2 size M M M M T M M M M M M M T Paste offset 470 427 433 513 448 105 103 115 452 282 342 397 76 Shrinkage 2.92 2.92 2.92 2.92 2.92 4.54 2.92 4.54 4.54 4.54 4.54 4.54 2.92 Creep value 30 156 81 41 156 156 81 81 30 156 81 41 81 ∆ab 0.85 0.52 0.88 0.98 0.77 2.3 1.45 2.32 1.12 1.07 1.65 1.46 2.01

[Evaluation] It can be seen from Table 1 that by controlling the paste offset of the first adhesive layer, the shrinkage rate of the retardation layer and the creep value of the second adhesive layer in combination, it can be obtained that the color unevenness can be achieved in a high temperature environment. Suppressed polarizing plate with retardation layer and adhesive layer of image display device. [Industrial availability]

The polarizing plate with retardation layer and adhesive layer of the present invention can be suitably used for image display devices (typically, liquid crystal display devices and organic EL display devices).

10: Polarizing plate 11: Polarizing element 12: The first protective layer 13: The second protective layer 20: The first adhesive layer 30: retardation layer 40: The second adhesive layer 100: Polarizing plate with retardation layer and adhesive layer

Fig. 1 is a schematic cross-sectional view of a polarizing plate with a retardation layer and an adhesive layer according to one embodiment of the present invention.

10: Polarizing plate

11: Polarizing element

12: The first protective layer

13: The second protective layer

20: The first adhesive layer

30: retardation layer

40: The second adhesive layer

100: Polarizing plate with retardation layer and adhesive layer

Claims (7)

A polarizing plate with a retardation layer and an adhesive layer, comprising: a polarizing plate, which includes a polarizing element; a retardation layer, which is attached to the polarizing plate via a first adhesive layer; and a second adhesive layer, which As the outermost layer, it is arranged on the side of the retardation layer opposite to the polarizing plate; and The retardation layer includes a stretched film of a resin film, which satisfies the relationship of Re(450)<Re(550), and the shrinkage rate in the slow axis direction when heated at 80°C to 125°C for 180 minutes is less than 4%; The paste offset of the first adhesive layer after a heating test at 85°C and 500 hours is more than 300 μm; Here, Re(450) and Re(550) are the in-plane phase differences measured by light with wavelengths of 450 nm and 550 nm at 23°C, respectively. The polarizing plate with retardation layer and adhesive layer of claim 1, wherein the Re(550) of the retardation layer is 100 nm to 200 nm, and the retardation axis of the retardation layer is the absorption axis of the polarizing element The angle formed is 40°～50° or 130°～140°. Such as claim 1 or 2 of the polarizing plate with retardation layer and adhesive layer, wherein the thickness of the retardation layer is 15 μm to 60 μm. The polarizing plate with retardation layer and adhesive layer according to any one of claims 1 to 3, wherein the stretched film constituting the retardation layer is heated at a temperature of 105° C. or higher for more than 2 minutes. For example, the polarizing plate with retardation layer and adhesive layer of any one of claims 1 to 4, which further has refractive index characteristics between the retardation layer and the second adhesive layer, showing nz>nx=ny Another phase difference layer of the relationship. The polarizing plate with a retardation layer and an adhesive layer according to any one of claims 1 to 5, wherein the retardation layer contains at least one type of bonding selected from the group consisting of carbonate bonds and ester bonds Base and at least one structural unit selected from the group consisting of the structural unit represented by the following general formula (1) and the structural unit represented by the following general formula (2), and having a positive refractive index anisotropy Resin; and acrylic resin; and the content of the acrylic resin is 0.5% by mass to 2.0% by mass, the acrylic resin contains more than 70% by mass of structural units derived from methyl methacrylate, and its weight average molecular weight Mw is 10,000 ~200,000; [Chemical 1]

[化2]

In the general formulas (1) and (2), R ¹ to R ³ are each independently a direct bond, a substituted or unsubstituted alkylene group having 1 to 4 carbon atoms, and R ⁴ to R ⁹ are each independently hydrogen Atom, substituted or unsubstituted alkyl group with 1-10 carbons, substituted or unsubstituted aryl group with 4-10 carbons, substituted or unsubstituted acyl group with 1-10 carbons, Substituted or unsubstituted alkoxy with 1 to 10 carbons, substituted or unsubstituted aryloxy with 1 to 10 carbons, substituted or unsubstituted amine, substituted or unsubstituted A vinyl group with 1 to 10 carbons, a substituted or unsubstituted ethynyl group with 1 to 10 carbons, a sulfur atom with a substituent, a silicon atom with a substituent, a halogen atom, a nitro group or a cyano group; R ⁴ to R ⁹ may be the same or different from each other, ^{and at least two adjacent groups among R 4} to R ⁹ may be bonded to each other to form a ring. An image display device provided with a polarizing plate with a retardation layer and an adhesive layer as claimed in any one of claims 1 to 6.

Images