A polarizing plate with a phase difference layer and an adhesive layer attached, and an image display device using the polarizing plate with the phase difference layer and the adhesive layer attached.

Abstract

The present invention provides a polarizing plate with a phase difference layer and an adhesive layer attached, which can realize an image display device in which phase difference non-uniformity is suppressed and color stains are suppressed in a high-temperature environment. The polarizing plate with a phase difference layer and an adhesive layer attached according to the present invention comprises a polarizing plate including a polarizer, a phase difference layer laminated to the polarizing plate with a first adhesive layer interposed therebetween, and a second adhesive layer provided as the outermost layer on the side opposite to the polarizing plate of the phase difference layer. The phase difference layer is composed of a stretched film of a resin film Re(450) <Re(550)의 관계를 만족하고, 80℃~125℃에서 180분까지의 시간 가열하였을 때의 지상축 방향의 수축률이 4% 이하이다. 제1 점착제층의 85℃ 및 500시간의 가열 시험 후의 풀 어긋남량은 300㎛ 이상이다.

Description

Technology Field

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

[0002] Recently, image display devices, such as liquid crystal displays and electroluminescence (EL) displays (e.g., organic EL displays, inorganic EL displays), have been rapidly popularized. Polarizers and phase difference plates are typically used in image display devices. In practical terms, polarizers with a phase difference layer attached, which integrate a polarizer and a phase difference plate, are widely used (e.g., Patent Document 1). However, polarizers with a phase difference layer attached may experience phase difference non-uniformity under high-temperature environments, and as a result, color stains may occur in the image display device under high-temperature environments. Prior art literature

[0003] Japanese Patent Publication No. 3325560, Japanese Published Patent Application No. 2022-013705 The problem to be solved

[0004] The present invention is made to solve the aforementioned conventional problems, and its main objective is to provide a polarizing plate with a phase difference layer and an adhesive layer attached, which can realize an image display device in which phase difference non-uniformity is suppressed and color staining is suppressed in a high-temperature environment. means of solving the problem

[0005] A polarizing plate with a phase difference layer and an adhesive layer attached according to an embodiment of the present invention comprises a polarizing plate including a polarizer, a phase difference layer laminated to the polarizing plate with a first adhesive layer interposed therebetween, and a second adhesive layer provided as the outermost layer on the side of the phase difference layer opposite to the polarizing plate. The phase difference layer is composed of a stretched film of a resin film, and Re(450) <Re(550)의 관계를 만족하고, 80℃~125℃에서 180분까지의 시간 가열하였을 때의 지상축 방향의 수축률이 4% 이하이다. 해당 제1 점착제층의 85℃ 및 500시간의 가열 시험 후의 풀 어긋남량은 300㎛ 이상이다. 여기에서, Re(450) 및 Re(550)은 각각, 23℃에서의 파장 450nm 및 550nm의 광으로 측정한 면내 위상차이다.

[0006] In one embodiment, the Re (550) of the phase difference layer is 100 nm to 200 nm, and the angle formed by the ground axis of the phase difference layer and the absorption axis of the polarizer is 40° to 50° or 130° to 140°.

[0007] In one embodiment, the thickness of the phase difference layer is 15㎛ to 60㎛.

[0008] In one embodiment, the stretched film constituting the phase difference layer is subjected to a heat treatment of heating at a temperature of 105°C or higher for 2 minutes or more.

[0009] In one embodiment, the polarizing plate with the phase difference layer and adhesive layer attached further includes another phase difference layer between the phase difference layer and the second adhesive layer, wherein the refractive index characteristics have a relationship of nz > nx = ny.

[0010] In one embodiment, the phase difference layer comprises at least one linking group selected from the group consisting of carbonate bonds and ester bonds, and at least one structural unit selected from the group consisting of a structural unit represented by the following general formula (1) and a structural unit represented by the following general formula (2), and comprises a resin having positive refractive index anisotropy; and an acrylic resin; wherein the content of the acrylic resin is 0.5 mass% to 2.0 mass%, the acrylic resin contains 70 mass% or more of a structural unit derived from methyl methacrylate, and the weight-average molecular weight (Mw) is 10,000 to 200,000:

[0011]

[0012]

[0013] Among general formulas (1) and (2), R 1 ~R 3 Each is independently a directly bonded, substituted, or unsubstituted alkylene group having 1 to 4 carbon atoms, and R 4 ~R 9 Each is independently a hydrogen atom, a substituted or unsubstituted C1-10 alkyl group, a substituted or unsubstituted C4-10 aryl group, a substituted or unsubstituted C1-10 acyl group, a substituted or unsubstituted C1-10 alkoxy group, a substituted or unsubstituted C1-10 aryloxy group, a substituted or unsubstituted amino group, a substituted or unsubstituted C1-10 vinyl group, a substituted or unsubstituted C1-10 ethenyl group, a sulfur atom having a substituent, a silicon atom having a substituent, a halogen atom, a nitro group, or a cyano group; provided, R 4 ~R 9 They may be identical or different, and R 4 ~R 9 At least two adjacent groups can combine to form a ring.

[0014] According to another aspect of the present invention, an image display device is provided. The image display device comprises a polarizing plate with the above-mentioned phase difference layer and adhesive layer attached thereto. Effects of the invention

[0015] According to an embodiment of the present invention, by optimizing the combination of the amount of adhesive misalignment between the polarizer and the phase difference layer and the heating shrinkage rate of the phase difference layer in the direction of the ground axis, it is possible to realize a polarizer with attached phase difference layer and adhesive layer in which phase difference non-uniformity is suppressed under high-temperature environments. As a result, an image display device in which color stains are suppressed under high-temperature environments can be realized. Brief explanation of the drawing

[0016] FIG. 1 is a schematic cross-sectional view of a polarizing plate with a phase difference layer and an adhesive layer attached according to one embodiment of the present invention. Specific details for implementing the invention

[0017] Representative embodiments of the present invention will be described below, but the present invention is not limited to these embodiments.

[0018] (Definition of Terms and Symbols)

[0019] The definitions of terms and symbols in this specification are as follows.

[0020] (1) Refractive index (nx, ny, nz)

[0021] 'nx' is the refractive index in the direction where the refractive index in the plane is maximum (i.e., the ground axis direction), 'ny' is the refractive index in the direction perpendicular to the ground axis in the plane (i.e., the true axis direction), and 'nz' is the refractive index in the thickness direction.

[0022] (2) In-plane phase difference (Re)

[0023] 'Re(λ)' is the in-plane phase difference of the film measured with light of wavelength λ nm at 23°C. For example, 'Re(450)' is the in-plane phase difference of the film measured with light of wavelength 450 nm at 23°C. Re(λ) is calculated by the formula: Re=(nx-ny)×d, where the thickness of the film is d(nm).

[0024] (3) Phase difference in the thickness direction (Rth)

[0025] 'Rth(λ)' is the phase difference in the thickness direction of the film measured with light of wavelength λ nm at 23°C. For example, 'Rth(450)' is the phase difference in the thickness direction of the film measured with light of wavelength 450 nm at 23°C. Rth(λ) is calculated by the formula: Rth=(nx-nz)×d, where the film thickness is d(nm).

[0026] (4) Nz coefficient

[0027] The Nz coefficient is calculated by Nz = Rth / Re.

[0028] (5) Angle

[0029] When referring to angles in this specification, unless specifically stated otherwise, said angle includes angles in both clockwise and counterclockwise directions.

[0030] A. Overall configuration of a polarizer with a phase difference layer and an adhesive layer attached

[0031] FIG. 1 is a schematic cross-sectional view of a polarizing plate with a phase difference layer and an adhesive layer attached according to one embodiment of the present invention. The polarizing plate (100) with a phase difference layer and an adhesive layer attached of the illustrated example comprises a polarizing plate (10), a phase difference layer (30) laminated to the polarizing plate (10) with a first adhesive layer (20) interposed therebetween, and a second adhesive layer (40) provided as an outermost layer on the side opposite to the polarizing plate (10) of the phase difference layer (30). By means of the second adhesive layer (40), the polarizing plate with a phase difference layer and an adhesive layer attached can be attached to an image display cell. The polarizing plate (10) comprises a polarizer (11), a first protective layer (12) disposed on one side of the polarizer (11), and a second protective layer (13) disposed on the other side of the polarizer (11). Depending on the purpose, one of the first protective layer (12) and the second protective layer (13) may be omitted. For example, since the phase difference layer (30) can also function as a protective layer for the polarizer (11), the second protective layer (13) may be omitted. The angle formed by the ground axis of the phase difference layer (30) and the absorption axis of the polarizer (11) is preferably 40° to 50°, more preferably 42° to 48°, even more preferably 44° to 46°, and particularly preferably about 45°; or, preferably 130° to 140°, more preferably 132° to 138°, even more preferably 134° to 136°, and particularly preferably about 135°.

[0032] The phase difference layer (30) is composed of a stretched film of resin film, and Re (450) <Re(550)의 관계를 만족하고, 80℃~125℃에서 180분까지의 시간 가열하였을 때의 지상축 방향의 수축률이 4% 이하이다. 위상차층(30)의 Re(550)은 대표적으로는 100nm~200nm이다. 제1 점착제층(20)의 85℃ 및 500시간의 가열 시험 후의 풀 어긋남량은 300㎛ 이상이다. 위상차층 및 점착제층 부착 편광판을 구성하는 각 층의 상세에 대해서는 후술한다.

[0033] In one embodiment, the polarizing plate with the phase difference layer and adhesive layer attached may further include another phase difference layer (not shown) between the phase difference layer (30) and the second adhesive layer (40). The other phase difference layer typically exhibits a refractive index characteristic of nz > nx = ny. By providing such another phase difference layer, reflection in the oblique direction can be effectively prevented, thereby enabling a wide viewing angle of the anti-reflection function.

[0034] In one embodiment, the polarizing plate with the phase difference layer and the adhesive layer attached may further include a conductive layer or an isotropic substrate with a conductive layer attached (not shown). When the conductive layer or the isotropic substrate with a conductive layer attached is provided, the polarizing plate with the phase difference layer and the adhesive layer attached may be applied to a so-called inner touch panel type input display device in which a touch sensor is embedded between an image display cell (e.g., an organic EL cell) and the polarizing plate. The conductive layer or the isotropic substrate with a conductive layer attached is typically provided between the phase difference layer (30) and the second adhesive layer (40). When another phase difference layer is provided, the other phase difference layer and the conductive layer or the isotropic substrate with a conductive layer attached are typically provided in this order from the phase difference layer (30) side.

[0035] The polarizing plate with attached phase difference layer and adhesive layer may include an additional phase difference layer (not shown). The additional phase difference layer may be provided in combination with another phase difference layer, or provided alone (i.e., without providing another phase difference layer). The optical properties (e.g., refractive index properties, in-plane phase difference, Nz modulus, photoelastic modulus), thickness, placement position, etc. of the additional phase difference layer may be appropriately set according to the purpose.

[0036] The polarizing plate with the phase difference layer and adhesive layer attached may be in the form of a single leaf or in the form of a long strip. In this specification, "long strip" refers to a slender shape in which the length is sufficiently long relative to the width, and includes, for example, a slender shape in which the length is 10 times or more, preferably 20 times or more, relative to the width. The polarizing plate with the phase difference layer and adhesive layer attached in the form of a long strip can be wound into a roll.

[0037] Practically, it is preferable that a release film be attached to the surface of the second adhesive layer (40) until the phase difference layer and the polarizing plate with the adhesive layer attached are provided for use. By attaching the release film, the second adhesive layer is protected, and at the same time, the phase difference layer and the polarizing plate with the adhesive layer attached can be rolled up.

[0038] The components of a polarizing plate with a phase difference layer and an adhesive layer attached are described below.

[0039] B. Polarizer

[0040] Any suitable polarizer may be used as the polarizer (11). For example, the resin film forming the polarizer may be a single-layer resin film or a laminate of two or more layers.

[0041] Specific examples of a polarizer composed of a single-layer resin film include a hydrophilic polymer film, such as a polyvinyl alcohol (PVA)-based film, a partially formalized PVA-based film, or a partially saponified ethylene-vinyl acetate copolymer-based film, which has been dyed with a dichroic substance such as iodine or a dichroic dye and subjected to stretching treatment, and a polyene-based oriented film, such as a dehydrated PVA or a dehydrochlorinated polyvinyl chloride. Preferably, a polarizer obtained by dyeing a PVA-based film with iodine and uniaxially stretching it is used because of its excellent optical properties.

[0042] The above iodine dyeing is performed, for example, by immersing a PVA-based film in an aqueous iodine solution. The stretching ratio of the above uniaxial stretching is preferably 3 to 7 times. Stretching may be performed after the dyeing treatment or while dyeing. In addition, dyeing may be performed after stretching. If necessary, swelling treatment, crosslinking treatment, washing treatment, drying treatment, etc., are performed on the PVA-based film. For example, by immersing the PVA-based film in water and washing it before dyeing, it is possible not only to wash away dirt or anti-blocking agents from the surface of the PVA-based film, but also to prevent dyeing stains by swelling the PVA-based film.

[0043] Specific examples of polarizers obtained using a laminate include a laminate of a resin substrate and a PVA-based resin layer (PVA-based resin film) laminated on the resin substrate, or a polarizer obtained using a laminate of a resin substrate and a PVA-based resin layer coated and formed on the resin substrate. A polarizer obtained using a laminate of a resin substrate and a PVA-based resin layer coated and formed on the resin substrate can be manufactured by, for example, applying a PVA-based resin solution to a resin substrate and drying it to form a PVA-based resin layer on the resin substrate to obtain a laminate of the resin substrate and the PVA-based resin layer; and stretching and dyeing the laminate to make the PVA-based resin layer a polarizer. In the present embodiment, stretching typically includes stretching the laminate by immersing it in an aqueous boric acid solution. Additionally, stretching may further include, if necessary, air-stretching the laminate at a high temperature (e.g., 95°C or higher) before stretching in the aqueous boric acid solution. The obtained resin substrate / polarizer laminate may be used as is (i.e., the resin substrate may be used as a protective layer for the polarizer), or the resin substrate may be peeled off from the resin substrate / polarizer laminate and any suitable protective layer according to the purpose may be laminated on the peeled surface and used. Details of such a method for manufacturing a polarizer are described, for example, in Japanese Patent Publication No. 2012-73580 and Japanese Patent Publication No. 6470455. The descriptions in these patent documents are incorporated herein by reference.

[0044] The polarizer can preferably be composed of a single layer of resin film. With such a configuration, a polarizing plate with a phase difference layer and an adhesive layer attached, in which phase difference non-uniformity under high-temperature environments is suppressed, can be obtained through a synergistic effect with the optimization of the first adhesive layer and the second adhesive layer.

[0045] The thickness of the polarizer is preferably 15 μm or less, more preferably 1 μm to 12 μm, and even more preferably 3 μm to 12 μm. If the thickness of the polarizer is within this range, curling during heating can be effectively suppressed, and good durability of the appearance during heating is obtained.

[0046] The polarizer preferably exhibits absorption dichroism at any wavelength between 380 nm and 780 nm. The single transmittance of the polarizer is, for example, 41.5% to 46.0%, preferably 43.0% to 46.0%, and more preferably 44.5% to 46.0%. The polarization degree of the polarizer is preferably 97.0% or higher, more preferably 99.0% or higher, and even more preferably 99.9% or higher.

[0047] C. Protective layer

[0048] The first protective layer (12) and the second protective layer (13) are each formed from any suitable film that can be used as a protective layer for a polarizer. Specific examples of materials that serve as the main components of the film include cellulose-based resins such as triacetylcellulose (TAC), or transparent resins such as polyester-based, polyvinyl alcohol-based, polycarbonate-based, polyamide-based, polyimide-based, polyethersulfone-based, polysulfone-based, polystyrene-based, polynorbornene-based, polyolefin-based, (meth)acrylic-based, and acetate-based resins. Additionally, thermosetting resins or UV-curing resins such as (meth)acrylic-based, urethane-based, (meth)acrylicurethane-based, epoxy-based, and silicone-based resins may also be used. Furthermore, glass-based polymers such as siloxane-based polymers may also be used. In addition, a polymer film described in Japanese Patent Publication No. 2001-343529 (WO01 / 37007) may also be used. As a material for this film, for example, a resin composition containing a thermoplastic resin having substituted or unsubstituted imide groups in a side chain and a thermoplastic resin having substituted or unsubstituted phenyl groups and nitrile groups in a side chain may be used, and for example, a resin composition having an alternating copolymer of isobutene and N-methylmaleimide and an acrylonitrile-styrene copolymer may be used. The polymer film may be, for example, an extruded product of the above resin composition.

[0049] As described below, the polarizing plate with the phase difference layer and adhesive layer attached is typically positioned on the viewing side of an image display device, and the first protective layer (12) is typically positioned on the viewing side. Accordingly, the first protective layer (12) may be subjected to surface treatments such as hard coating, anti-reflection, anti-sticking, and anti-glare treatment as needed. Additionally / or, the first protective layer (12) may be subjected to a treatment that improves visibility when viewed through polarized sunglasses (typically, providing an ellipsis polarization function, providing an ultra-high phase difference) as needed. By performing such a treatment, excellent visibility can be achieved even when viewing the display screen through polarized lenses such as polarized sunglasses. Accordingly, the polarizing plate with the phase difference layer and adhesive layer attached can be suitably applied to an image display device that can be used outdoors.

[0050] The thickness of the first protective layer is typically 300 μm or less, preferably 100 μm or less, more preferably 5 μm to 80 μm, and even more preferably 10 μm to 60 μm. In addition, if surface treatment is performed, the thickness of the outer protective layer is the thickness including the thickness of the surface treatment layer.

[0051] In one embodiment, the second protective layer (13) is preferably optically isotropic. In this specification, "optically isotropic" means that the in-plane phase difference Re (550) is 0 nm to 10 nm and the thickness direction phase difference Rth (550) is -10 nm to +10 nm.

[0052] C. Phase difference layer

[0053] C-1. Characteristics of the phase difference layer

[0054] As mentioned above, the in-plane phase difference Re (550) of the phase difference layer is 100 nm to 200 nm, preferably 110 nm to 180 nm, more preferably 120 nm to 160 nm, and even more preferably 130 nm to 150 nm. That is, the phase difference layer can function as a so-called λ / 4 plate.

[0055] The phase difference layer is Re(450) as described above <Re(550)의 관계를 만족하고, 바람직하게는 Re(550)<Re(650)의 관계를 더욱 만족한다. 즉, 위상차층은 위상차값이 측정광의 파장에 따라 커지는 역분산의 파장 의존성을 나타낸다. 위상차 필름의 Re(450) / Re(550)은 예컨대 0.5 초과 1.0 미만이고, 바람직하게는 0.7~0.95이며, 보다 바람직하게는 0.75~0.92이고, 더 바람직하게는 0.8~0.9이다. Re(650) / Re(550)은 바람직하게는 1.0 이상 1.15 미만이며, 보다 바람직하게는 1.03~1.1이다.

[0056] Since the phase difference layer has an in-plane phase difference as described above, it has the relationship nx > ny. As long as the relationship nx > ny is maintained, the phase difference layer exhibits any appropriate refractive index characteristic. The refractive index characteristic of the phase difference layer typically exhibits the relationship nx > ny ≥ nz. Furthermore, here, 'ny = nz' includes not only the case where ny and nz are completely identical, but also the case where they are substantially identical. Therefore, within a scope that does not impair the effects of the present invention, ny <nz가 되는 경우가 있을 수 있다. 위상차층의 Nz 계수는 바람직하게는 0.9~2.0이고, 보다 바람직하게는 0.9~1.5이며, 더 바람직하게는 0.9~1.2이다. 이와 같은 관계를 만족하는 것에 의해, 위상차층 및 점착제층 부착 편광판을 화상 표시 장치에 이용한 경우에, 매우 우수한 반사 색상을 달성할 수 있다.

[0057] The thickness of the phase difference layer can be set so that it functions most appropriately as a λ / 4 plate. In other words, the thickness can be set so that a desired in-plane phase difference is 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 an embodiment of the present invention, the thickness of the phase difference layer can be made significantly thinner compared to a λ / 4 plate composed of a conventional resin film.

[0058] In an embodiment of the present invention, the shrinkage rate in the direction of the ground axis when the phase difference layer is heated at a temperature of 80°C to 125°C for a time of up to 180 minutes is 4% or less as described above, preferably 3.5% or less, and more preferably 3% or less. It is preferable for the shrinkage rate to be smaller, and its lower limit may be, for example, 0.5%.

[0059] The elongation at break of the stretched film constituting the phase difference layer is preferably 200% or more, more preferably 210% or more, even more preferably 220% or more, and particularly preferably 245% or more. The upper limit of the elongation at break may be, for example, 500%. Since the stretched film used in the phase difference layer in the embodiment of the present invention has excellent phase difference expression properties and also excellent elongation properties, a desired in-plane phase difference can be realized at a very thin thickness due to the synergistic effect of these properties. Furthermore, in this specification, "elongation at break" refers to the elongation rate when the film breaks during fixed-end uniaxial stretching at a predetermined stretching temperature (e.g., Tg-2°C).

[0060] The phase difference layer preferably has an absolute value of its photoelastic modulus of 20×10 -12 (m 2 / N) or less, and more preferably 1.0×10 -12 (m 2 / N)~15×10 -12 (m 2 / N) and, more preferably 2.0×10 -12 (m2 / N)~12×10 -12 (m 2 / N). If the absolute value of the photoelastic modulus is within this range, non-uniformity in display can be suppressed when a polarizing plate with a phase difference layer and an adhesive layer attached is applied to an image display device.

[0061] C-2. Constituent materials of the phase difference layer

[0062] The phase difference layer typically comprises a resin containing at least one linking group selected from the group consisting of carbonate bonds and ester bonds. In other words, the phase difference layer comprises a polycarbonate-based resin, a polyester-based resin, or a polyester-carbonate-based resin (hereinafter collectively referred to as polycarbonate-based resin, etc.). The polycarbonate-based resin, etc. comprises at least one structural unit selected from the group consisting of the structural unit represented by the above general formula (1) and / or the structural unit represented by the above general formula (2). These structural units are structural units derived from divalent oligofluorene, and are hereinafter referred to as oligofluorene structural units. Such polycarbonate-based resin, etc. has positive refractive index anisotropy.

[0063] The phase difference layer typically further contains an acrylic resin. The content of the acrylic resin is 0.5 mass% to 1.5 mass%. Additionally, in this specification, a percentage or part in 'mass' units is equivalent to a percentage or part in 'weight' units.

[0064] C-2-1. Polycarbonate resins, etc.

[0065] Oligofluorene structural unit

[0066] The oligofluorene structural unit is represented by the above general formula (1) or (2). Among general formulas (1) and (2), R 1 ~R 3 Each is independently a directly bonded, substituted, or unsubstituted alkylene group having 1 to 4 carbon atoms, and R 4~R 9 Each is independently a hydrogen atom, a substituted or unsubstituted C1-10 alkyl group, a substituted or unsubstituted C4-10 aryl group, a substituted or unsubstituted C1-10 acyl group, a substituted or unsubstituted C1-10 alkoxy group, a substituted or unsubstituted C1-10 aryloxy group, a substituted or unsubstituted amino group, a substituted or unsubstituted C1-10 vinyl group, a substituted or unsubstituted C1-10 ethenyl group, a sulfur atom having a substituent, a silicon atom having a substituent, a halogen atom, a nitro group, or a cyano group. provided that R 4 ~R 9 They may be identical or different, and R 4 ~R 9 At least two adjacent groups can combine to form a ring.

[0067] The content of oligofluorene structural units in polycarbonate-based resins, etc., is preferably 1% to 40% by mass with respect to the total resin, more preferably 10% to 35% by mass, even more preferably 15% to 30% by mass, and particularly preferably 18% to 25% by mass. If the content of oligofluorene structural units is excessively high, there is a risk that problems may arise, such as the photoelastic modulus becoming excessively large, reliability becoming insufficient, or phase difference expression becoming insufficient. In addition, as the proportion of oligofluorene structural units in the resin increases, the range of molecular design narrows, and there are cases where modification becomes difficult when resin modification is required. On the other hand, even if the desired inverse dispersion wavelength dependence is obtained with a very small amount of oligofluorene structural units, in this case, optical properties change sensitively according to slight deviations in the content of oligofluorene structural units, so it may become difficult to manufacture the product so that various properties fall within a certain range.

[0068] Details of the oligofluorene structural unit are described, for example, in International Publication No. 2015 / 159928. Such publication is incorporated herein by reference.

[0069] Other structural units

[0070] Polycarbonate-based resins, etc., may typically include other structural units in addition to oligofluorene structural units. In one embodiment, the other structural units may preferably be derived from dihydroxy compounds or diester compounds. Since it is necessary to introduce structural units having positive intrinsic birefringence into the polymer structure along with oligofluorene structural units having negative intrinsic birefringence in order to express the desired inverse dispersion wavelength properties, dihydroxy compounds or diester compounds that serve as the raw material for structural units having positive birefringence are more preferred as the other monomers copolymerized.

[0071] Examples of copolymer monomers include compounds capable of introducing structural units containing aromatic rings, and compounds that do not introduce structural units containing aromatic rings, i.e., compounds composed of aliphatic structures.

[0072] Specific examples of compounds composed of the above-mentioned aliphatic structure are given below. Dihydroxy compounds of straight-chain aliphatic hydrocarbons such as ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 1,5-heptanediol, 1,6-hexanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol; dihydroxy compounds of branched aliphatic hydrocarbons such as neopentyl glycol, hexylene glycol; Secondary alcohols of alicyclic hydrocarbons, exemplified by 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,3-adamantandiol, hydrogenated bisphenol A, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, etc., and dihydroxy compounds that are tertiary alcohols; Dihydroxy compounds that are primary alcohols of alicyclic hydrocarbons, exemplified by dihydroxy compounds derived from terpene compounds such as 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, tricyclodecanedimethanol, pentacyclopentadecanedimethanol, 2,6-decalindimethanol, 1,5-decalindimethanol, 2,3-decalindimethanol, 2,3-novonandimethanol, 2,5-novonandimethanol, 1,3-adamantanedimethanol, limonene, etc.; oxyalkylene glycols such as diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, polypropylene glycol, etc.; dihydroxy compounds having a cyclic ether structure such as isosorbide; Dihydroxy compounds having a cyclic acetal structure such as spiroglycol and dioxane glycol; alicyclic dicarboxylic acids such as 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid; aliphatic dicarboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, souveric acid, azelaic acid, and sebacic acid.

[0073] Specific examples of compounds capable of introducing structural units including the above aromatic ring are given below. 2,2-Bis(4-hydroxyphenyl)propane, 2,2-Bis(3-methyl-4-hydroxyphenyl)propane, 2,2-Bis(4-hydroxy-3,5-dimethylphenyl)propane, 2,2-Bis(4-hydroxy-3,5-diethylphenyl)propane, 2,2-Bis(4-hydroxy-(3-phenyl)phenyl)propane, 2,2-Bis(4-hydroxy-(3,5-diphenyl)phenyl)propane, 2,2-Bis(4-hydroxy-3,5-dibromophenyl)propane, Bis(4-hydroxyphenyl)methane, 1,1-Bis(4-hydroxyphenyl)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)sulfone, 2,4'-dihydroxydiphenylsulfone, Aromatic bisphenol compounds such as 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; dihydroxy compounds having an ether group bonded to an aromatic group, such as 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, and bis(4-(2-hydroxyethoxy)phenyl)sulfone; Aromatic dicarboxylic acids such as terephthalic acid, phthalic acid, isophthalic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-diphenyletherdicarboxylic acid, 4,4'-benzophenonedicarboxylic acid, 4,4'-diphenoxyethanedicarboxylic acid, 4,4'-diphenylsulfonedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, etc.

[0074] In addition, the aliphatic dicarboxylic acid and aromatic dicarboxylic acid components mentioned above can be used as the dicarboxylic acid itself as a raw material for the polyester carbonate, but depending on the manufacturing method, dicarboxylic acid esters such as methyl esters and phenyl esters, or dicarboxylic acid derivatives such as dicarboxylic acid halides, may also be used as raw materials.

[0075] Dihydroxy compounds having a fluorene ring, such as 9,9-bis(4-(2-hydroxyethoxy)phenyl)fluorene, 9,9-bis(4-hydroxyphenyl)fluorene, and 9,9-bis(4-hydroxy-3-methylphenyl)fluorene, which are conventionally known as copolymer monomers having structural units with negative birefringence, or dicarboxylic acid compounds having a fluorene ring, can also be used in combination with oligofluorene compounds.

[0076] The resin used in the present invention preferably contains a structural unit represented by the following formula (3) as a copolymer component, among the structural units that can be introduced by the compound having the above-mentioned alicyclic structure.

[0077]

[0078] Spiroglycol can be used as a dihydroxy compound capable of introducing the structural unit of the above formula (3).

[0079] In the resin used in the present invention, it is preferable that the structural unit represented by Formula (3) be contained in an amount of 5 mass% or more and 90 mass% or less. The upper limit is more preferably 70 mass% or less, and particularly preferably 50 mass% or less. The lower limit is more preferably 10 mass% or more, more preferably 20 mass% or more, and particularly preferably 25 mass% or more. If the content of the structural unit represented by Formula (3) is above the lower limit, sufficient mechanical properties, heat resistance, and a low photoelastic modulus are obtained. In addition, compatibility with acrylic resins is improved, which can further enhance the transparency of the resulting resin composition. Furthermore, since the polymerization reaction rate of spiroglycol is relatively slow, it becomes easier to control the polymerization reaction by keeping the content below the upper limit.

[0080] The resin used in the present invention preferably additionally contains a structural unit as a copolymer component, as shown in the following formula (4).

[0081]

[0082] Examples of dihydroxy compounds capable of introducing the structural unit shown in the above formula (4) include isosorbide (ISB), isomandide, and isoidet, which are stereoisomers. These may be used individually or in combination of two or more types.

[0083] In the resin used in the present invention, it is preferable that the structural unit represented by Formula (4) be contained in an amount of 5 mass% or more and 90 mass% or less. The upper limit is more preferably 70 mass% or less, and particularly preferably 50 mass% or less. The lower limit is more preferably 10 mass% or more, and particularly preferably 15 mass% or more. If the content of the structural unit represented by Formula (4) is above the lower limit, sufficient mechanical properties, heat resistance, and a low photoelastic modulus are obtained. In addition, since the structural unit represented by Formula (4) has a high water absorption characteristic, if the content of the structural unit represented by Formula (4) is below the upper limit, the dimensional change of the molded body due to absorption can be suppressed to an acceptable range.

[0084] The resin used in the present invention may include other structural units. Furthermore, such structural units may be referred to as "other structural units." As monomers having other structural units, it is more preferable to use 1,4-cyclohexanedimethanol, tricyclodecanedimethanol, and 1,4-cyclohexanedicarboxylic acid (and their derivatives), and 1,4-cyclohexanedimethanol and tricyclodecanedimethanol are particularly preferred. Resins containing structural units derived from these monomers exhibit an excellent balance of optical properties, heat resistance, mechanical properties, etc. Additionally, since the polymerization reactivity of diester compounds is relatively low, it is preferable not to use diester compounds other than those containing oligofluorene structural units in order to increase reaction efficiency.

[0085] The glass transition temperature (Tg) of the resin used in the present invention is preferably 110°C or higher and 160°C or lower. 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, and particularly preferably 130°C or higher. If the glass transition temperature is outside the above range, heat resistance tends to deteriorate, which may cause dimensional changes after film forming or deteriorate the reliability of quality under the usage conditions of the phase difference film. On the other hand, if the glass transition temperature is excessively high, non-uniformity of film thickness may occur during film forming, the film may become soft, or stretchability may deteriorate, and the transparency of the film may also be compromised.

[0086] Details regarding the composition and manufacturing methods of polycarbonate-based resins, etc., are described, for example, in International Publication No. 2015 / 159928 (above). This description is incorporated herein by reference.

[0087] C-2-2. Acrylic Resin

[0088] As for acrylic resins, acrylic resins are used as thermoplastic resins. Examples of monomers serving as structural units of acrylic resins include the following compounds: methyl methacrylate, methacrylic acid, methyl acrylate, acrylic acid, benzyl (meth)acrylate, n-butyl (meth)acrylate, i-butyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, stearyl (meth)acrylate, glycidyl (meth)acrylate, hydroxypropyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, norbornyl (meth)acrylate, dicyclopentenyl (meth)acrylate. Dicyclofentanyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, acrylate (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-(meth)acryloyloxyethyl succinic acid, 2-(meth)acryloyloxyethyl maleic acid, 2-(meth)acryloyloxyethyl phthalic acid, 2-(meth)acryloyloxyethyl hexahydrophthalic acid, pentamethylpiperidyl (meth)acrylate, tetramethylpiperidyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, cyclopentyl methacrylate, cyclopentyl acrylate, cyclohexyl methacrylate, cyclohexyl acrylate, cycloheptyl methacrylate, Cycloheptyl acrylate, cyclooctyl methacrylate, cyclooctyl acrylate, cyclododecyl methacrylate, cyclododecyl acrylate. These may be used individually or in combination of two or more types. Examples of forms in which two or more monomers are used in combination include copolymerization of two or more monomers, blends of two or more homopolymers of one monomer, and combinations thereof. In addition, other monomers copolymerizable with these acrylic monomers (e.g., olefin monomers, vinyl monomers) may be used in combination.

[0089] The acrylic resin contains structural units derived from methyl methacrylate. The content of structural units derived from methyl methacrylate in the acrylic resin is preferably 70 mass% or more and 100 mass% or less. The lower limit is more preferably 80 mass% or more, more preferably 90 mass% or more, and particularly preferably 95 mass% or more. Within this range, excellent compatibility with the polycarbonate resin of the present invention is obtained. As structural units other than methyl methacrylate, it is preferable to use methyl acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, and styrene. Thermal stability can be improved by copolymerizing methyl acrylate. Since the refractive index of the acrylic resin can be adjusted by using phenyl (meth)acrylate, benzyl (meth)acrylate, and styrene, the transparency of the resulting resin composition can be improved by matching it to the refractive index of the combined resin. By using such an acrylic resin, an inverse dispersion phase difference film with excellent extensibility and phase difference expression, and also low haze, can be obtained.

[0090] 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, and particularly preferably 50,000 or more. The upper limit is preferably 180,000 or less, and particularly preferably 150,000 or less. When the molecular weight is within this range, compatibility with the polycarbonate resin is achieved, thereby improving the transparency of the final phase difference film (phase difference layer) and also achieving the effect of sufficiently improving elongation during stretching. Furthermore, the above weight-average molecular weight is the polystyrene equivalent molecular weight measured by GPC. Additionally, from the perspective of compatibility, it is preferable that the acrylic resin does not substantially contain a branched structure. The absence of a branched structure can be confirmed by the fact that the GPC curve of the acrylic resin is unimodal, etc.

[0091] C-2-3. Blends of polycarbonate resins, etc., with acrylic resins

[0092] Polycarbonate-based resins and acrylic-based resins are blended and provided as a resin composition for a method of manufacturing a phase difference film (phase difference layer) (the manufacturing method is described later in Clause C-3). Polycarbonate-based resins and acrylic-based resins can preferably be blended in a molten state. A representative method for blending in a molten state is melt mixing using an extruder. The mixing temperature (molten resin temperature) is preferably 200°C to 280°C, more preferably 220°C to 270°C, and even more preferably 230°C to 260°C. If the mixing temperature is within this range, pellets of a resin composition in which both resins are uniformly blended can be obtained while suppressing thermal decomposition. If the molten resin temperature in the extruder exceeds 280°C, discoloration of the resin and / or thermal decomposition may occur. On the other hand, if the molten resin temperature in the extruder falls below 200°C, the resin viscosity becomes excessively high, which may result in an excessive load on the extruder or insufficient melting of the resin. In addition, any suitable configuration may be adopted for the configuration of the extruder, screw, etc. To obtain the transparency of the resin suitable for optical film applications, it is preferable to use a twin-screw extruder. Furthermore, since residual low-molecular-weight components in the resin or low-molecular-weight thermal decomposition components during extrusion mixing may contaminate the cooling roll or conveyor roll during the film-making or stretching process, it is preferable to use an extruder equipped with a vacuum vent to remove them.

[0093] As described above, the content of the acrylic resin in the resin composition (consequently, the phase difference layer) is 0.5 mass% or more and 2.0 mass% or less. A lower limit of 0.6 mass% or more is more preferable. An upper limit of 1.5 mass% or less is preferred, 1.0 weight% or less is more preferable, 0.9 weight% or less is more preferable, and 0.8 mass% or less is particularly preferable. In this way, by incorporating the acrylic resin into the polycarbonate resin in an extremely limited proportion, the extensibility and phase difference performance can be significantly increased. Furthermore, haze can be suppressed. Such effects are not theoretically clear and are unexpected excellent effects obtained through trial and error. Additionally, if the content of the acrylic resin is excessively low, the above effects may not be obtained. On the other hand, if the content of the acrylic resin is excessively high, the haze may increase. Moreover, compared to cases within the above range, the extensibility and phase difference performance often become insufficient or even decrease.

[0094] For the purpose of modifying properties such as mechanical properties and / or solvent resistance, the resin composition may further be blended with synthetic resins such as aromatic polycarbonate, aliphatic polycarbonate, aromatic polyester, aliphatic polyester, polyamide, polystyrene, polyolefin, acrylic, amorphous polyolefin, ABS, AS, polylactic acid, and polybutylene succinate, rubber, and combinations thereof.

[0095] The resin composition may further include additives. Specific examples of additives include heat stabilizers, antioxidants, catalyst deactivators, ultraviolet absorbers, light stabilizers, release agents, dye pigments, impact modifiers, antistatic agents, lubricants, plasticizers, compatibilizers, nucleating agents, flame retardants, inorganic fillers, and foaming agents. The type, number, combination, and content of additives included in the resin composition can be appropriately set according to the purpose.

[0096] C-3. Method for forming a phase difference layer

[0097] A phase difference layer is obtained by forming a film with the resin composition described in Clause C-2 above and by stretching the film. Any suitable molding process may be employed as the method for forming the film with the resin composition. Specific examples include compression molding, transfer molding, injection molding, extrusion molding, blow molding, powder molding, FRP molding, cast coating (e.g., flexible molding), calendering, and heat pressing. Among these, extrusion molding or cast coating is preferred as it can increase the smoothness of the resulting film and obtain good optical uniformity. Since there is a risk of problems caused by residual solvent in cast coating, extrusion molding is particularly preferred, and among them, melt extrusion molding using a T-die is preferred from the perspective of film productivity and ease of subsequent stretching treatment. Molding conditions can be appropriately set according to the composition or type of resin used and the desired characteristics of the phase difference layer. In this way, a resin film containing a polycarbonate-based resin, etc., and an acrylic-based resin can be obtained.

[0098] The thickness of the resin film (unoriented film) can be set to any appropriate value depending on the desired thickness of the phase difference layer obtained, the desired optical properties, the stretching conditions described below, etc. Preferably, it is 50㎛ to 300㎛.

[0099] For the above stretching, any appropriate stretching method and stretching conditions (e.g., stretching temperature, stretching ratio, stretching direction) may be employed. Specifically, various stretching methods such as free-end stretching, fixed-end stretching, free-end shrinkage, and fixed-end shrinkage may be used individually, or they may be used simultaneously or sequentially. Regarding the stretching direction, it may also be performed in various directions or dimensions, such as the length direction, width direction, thickness direction, and inclination direction.

[0100] By appropriately selecting the above stretching method and stretching conditions, a phase difference layer having the above desired optical properties (e.g., refractive index properties, in-plane phase difference, Nz coefficient) can be obtained.

[0101] In one embodiment, the stretching temperature of the above film is a temperature below the glass transition temperature (Tg) of a polycarbonate-based resin, etc. Typically, when stretching a film of a polycarbonate-based resin, etc., stretching is practically impossible at temperatures below Tg because the film is in a glass state. According to the resin film used in the embodiment of the present invention, by incorporating a small amount of acrylic resin (typically polymethyl methacrylate), stretching at Tg or below becomes possible without substantially changing the Tg of the polycarbonate-based resin, etc. Furthermore, although not theoretically clear, by performing stretching at Tg or below, it is possible to realize a reverse dispersion phase difference film (phase difference layer) with excellent elongation and phase difference expression properties and low haze. Specifically, the stretching temperature is preferably Tg to Tg-10°C, more preferably Tg to Tg-8°C, and even more preferably Tg to Tg-5°C. In addition, the above film can be appropriately stretched even at a temperature higher than Tg, for example, up to about Tg + 5°C, and for example, up to about Tg + 2°C.

[0102] The stretched film obtained as described above is preferably subjected to a heat treatment of heating at a temperature of 105°C or higher for at least 2 minutes. By performing the heat treatment, a phase difference layer having the desired shrinkage rate can be formed. The heating temperature is preferably 105°C to 140°C, more preferably 110°C to 130°C, and even more preferably 115°C to 125°C. The heating time is preferably 2 minutes to 150 minutes, more preferably 3 minutes to 120 minutes, and even more preferably 5 minutes to 60 minutes.

[0103] If necessary, the stretched film may be subjected to a relaxation treatment. By doing so, the stress generated by stretching can be relieved, thereby forming a phase difference layer having the desired shrinkage rate. Any suitable condition may be adopted as the relaxation treatment condition. For example, the stretched film is shrunk along the stretching direction at a predetermined relaxation temperature and a predetermined relaxation rate (shrinkage rate). The relaxation temperature is preferably 60°C to 150°C. The relaxation rate is preferably 3% to 6%. When the relaxation treatment is performed, the relaxation treatment may typically be performed before the heat treatment.

[0104] In this way, a phase difference film constituting a phase difference layer can be obtained.

[0105] D. First adhesive layer and second adhesive layer

[0106] D-1. Characteristics of the first adhesive layer and / or the second adhesive layer

[0107] As described above, the first adhesive layer (20) has a glue misalignment amount of 300 μm or more after a heating test at 85°C and 500 hours, preferably 330 μm or more, more preferably 360 μm or more, even more preferably 390 μm or more, and particularly preferably 420 μm or more. The upper limit of the glue misalignment amount may be, for example, 600 μm. By using an adhesive with such a large glue misalignment amount for bonding the polarizer and the phase difference layer, a polarizing plate with a phase difference layer and an adhesive layer attached can be realized, with the synergistic effect of controlling the shrinkage rate of the phase difference layer in the ground axis direction and controlling the creep value of the second adhesive layer described later, in which phase difference non-uniformity under a high-temperature environment is suppressed. In addition, in this specification, "full deviation amount" refers to the length of the largest portion of the adhesive layer protruding from the end surface of the polarizer and the phase difference layer after a heating test in a polarizer with the phase difference layer and the adhesive layer attached.

[0108] The second adhesive layer (40) has a creep value at 23°C of, for example, 5 μm or more, preferably 20 μm or more, more preferably 30 μm or more, even more preferably 60 μm or more, particularly preferably 100 μm or more, and most preferably 120 μm or more. The upper limit of the creep value may be, for example, 300 μm. By using an adhesive with such a large creep value for bonding to an image display cell of a phase difference layer and an adhesive layer-attached polarizer, an image display device with suppressed color staining in a high-temperature environment can be realized through the synergistic effect of controlling the shrinkage rate of the phase difference layer in the ground axis direction and controlling the amount of adhesive misalignment of the first adhesive layer. The creep value may be measured in, for example, the following order: A test sample cut from the adhesive sheet is bonded to a support plate on a bonding surface of 10 mm × 10 mm. With the support plate to which the test sample is attached fixed, a load of 500gf is applied vertically downward. The amount of displacement from the support plate is measured 1 second and 3600 seconds after the load is applied, and Cr1 and Cr, respectively. 3600 It shall be done as. Cr1 and Cr 3600 ΔCr, obtained from the following formula, is used as the creep value. Additionally, the creep value in this specification is the value when the thickness of the adhesive layer is converted to 20 μm.

[0109] ΔCr=Cr 3600 -Cr1

[0110] The first adhesive layer and / or the second adhesive layer preferably has a storage modulus of 1.0 × 10 at 85°C. 4 Pa or higher, preferably 2.0×10 4 Pa or more, and more preferably 5.0×10 4 Pa or more, and more preferably 1.0×10 5 It is Pa or greater. If the storage modulus is within this range, the realization of the desired pull displacement amount and / or creep value becomes easier. On the other hand, the storage modulus is, for example, 3.0 × 10⁻⁶6 Pa is less than or equal to

[0111] The thickness of the first adhesive layer is preferably 2㎛ to 50㎛, and more preferably 3㎛ to 40㎛. The thickness of the second adhesive layer is preferably 4㎛ to 30㎛, and more preferably 5㎛ to 20㎛. If the thicknesses of the first adhesive layer and the second adhesive layer are within this range, a polarizing plate with a phase difference layer and an adhesive layer attached can be realized in which phase difference non-uniformity in a high-temperature environment is suppressed due to the synergistic effect with the effect of controlling the amount of glue misalignment and creep value, and an image display device in which color stains in a high-temperature environment are suppressed can also be realized.

[0112] D-2. Constituent materials of the first adhesive layer and the second adhesive layer

[0113] Any suitable configuration may be adopted for the first adhesive layer and the second adhesive layer, provided that the first adhesive layer has the desired adhesive misalignment amount and the second adhesive layer has the desired creep value. The first adhesive layer and the second adhesive layer may be composed of the same adhesive or may each be composed of different adhesives. Hereinafter, the constituent materials are described by combining the first adhesive layer and the second adhesive layer to form the adhesive layer. The adhesive misalignment amount and / or creep value can be controlled by adjusting the composition of the adhesive constituting the adhesive layer (e.g., type of base polymer (polarity, Tg, flexibility), molecular weight), crosslinking structure (e.g., type of crosslinking agent, distance between crosslinking points (molecular weight between crosslinking points), crosslinking density), etc.

[0114] D-2-1. Base Polymer

[0115] The adhesive layer is typically formed from 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 from an adhesive composition containing, for example, a (meth)acrylic polymer (A). The (meth)acrylic polymer (A) contains an alkyl (meth)acrylate as a main component.

[0116] <(Matte)Acrylic Polymer (A)>

[0117] As described above, the (meth)acrylic polymer (A) contains an alkyl (meth)acrylate as a main component. The alkyl (meth)acrylate is preferably 50% by weight or more in the total monomer components forming the (meth)acrylic polymer (A) to improve the adhesion of the adhesive layer, and can be arbitrarily set as the remainder of the monomer other than the alkyl (meth)acrylate. In addition, (meth)acrylate refers to acrylate and / or methacrylate.

[0118] Examples of alkyl (meth)acrylates constituting the main framework of the (meth)acrylic polymer (A) include straight-chain or branched-chain alkyl groups having 1 to 18 carbon atoms. Examples of alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, amyl, hexyl, cyclohexyl, heptyl, 2-ethylhexyl, isooctyl, nonyl, decyl, isodecyl, dodecyl, isomyristyl, lauryl, tridecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, etc. Alkyl (meth)acrylates may be used alone or in combination. It is preferable that the average number of carbon atoms of the alkyl groups be 3 to 10.

[0119] The (meth)acrylic polymer (A) may contain copolymer monomers such as a carboxyl group-containing monomer (a1) and a hydroxyl group-containing monomer (a2) in addition to alkyl (meth)acrylate as monomer components. The copolymer monomers may be used alone or in combination.

[0120] A carboxyl group-containing monomer (a1) is a compound that contains a carboxyl group in its structure and also contains a polymerizable unsaturated double bond such as a (meth)acryloyl group or a vinyl group. Examples of carboxyl group-containing monomers include (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, etc. Among these, acrylic acid is preferred in terms of copolymerization, cost, and improving the adhesive properties of the adhesive layer.

[0121] When a carboxyl group-containing monomer (a1) is used as a monomer component, the content of the carboxyl group-containing monomer (a1) is typically 0.01% by weight or more and 10% by weight or less in the total monomer components forming the (meth)acrylic polymer (A).

[0122] A hydroxyl group-containing monomer (a2) is a compound that contains a hydroxyl group in its structure and also contains a polymerizable unsaturated double bond such as a (meth)acryloyl group or a vinyl group. Examples of hydroxyl group-containing monomers include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, and 12-hydroxylauryl (meth)acrylate; and (4-hydroxymethylcyclohexyl)-methylacrylate. Among these, 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are preferred from the perspective of improving the durability of the adhesive layer, and 4-hydroxybutyl (meth)acrylate is more preferred.

[0123] When a hydroxyl group-containing monomer (a2) is used as a monomer component, the content of the hydroxyl group-containing monomer (a2) is typically 0.01% by weight or more and 10% by weight or less in the total monomer components forming the (meth)acrylic polymer (A).

[0124] The (meth)acrylic polymer (A) preferably contains, as a monomer component, a monomer having unsaturated carbon double bonds with a glass transition temperature of 0°C or higher. Examples of monomers (a3) ​​having unsaturated carbon double bonds with a glass transition temperature of 0°C or higher include alkyl (meth)acrylate monomers and (meth)acrylic acid. Monomer (a3) ​​is preferably a monomer having unsaturated carbon double bonds with a glass transition temperature of 20°C or higher, and more preferably a monomer having unsaturated carbon double bonds with a glass transition temperature of 40°C or higher.

[0125] The proportion of monomer (a3) ​​contained in the (meth)acrylic polymer (A) is not particularly limited. The content is typically 0.1% to 40% by weight, and more preferably 1% to 30% by weight. In addition, if two or more types of monomer (a3) ​​are used in combination, the content is the total content.

[0126] As monomer (a3), for example, straight-chain alkyl (meth)acrylates such as 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-hexadecyl acrylate (Tg: 35°C), n-hexadecyl methacrylate (Tg: 15°C), n-stearyl acrylate (Tg: 30°C), and n-stearyl methacrylate (Tg: 38°C); Examples include branched-chain alkyl (meth)acrylates such as t-butyl acrylate (Tg: 43°C), t-butyl methacrylate (Tg: 48°C), i-propyl methacrylate (Tg: 81°C), and i-butyl methacrylate (Tg: 48°C); cyclic alkyl (meth)acrylates such as cyclohexyl acrylate (Tg: 19°C), cyclohexyl methacrylate (Tg: 65°C), isobornyl acrylate (Tg: 94°C), and isobornyl methacrylate (Tg: 180°C); and acrylic acid (Tg: 106°C). These may be used alone or in combination.

[0127] Copolymer monomers serve as reaction sites with the crosslinking agent when the adhesive composition contains the crosslinking agent described below. Since carboxyl group-containing monomers and hydroxyl group-containing monomers have high reactivity with intermolecular crosslinking agents, they are preferably used to improve the cohesiveness or heat resistance of the resulting adhesive layer. Furthermore, carboxyl group-containing monomers are desirable for achieving both durability and reworkability, while hydroxyl group-containing monomers are desirable for improving reworkability.

[0128] Other copolymer monomers (a4) may also be used as monomer components. Other copolymer monomers (a4) have polymerizable functional groups having unsaturated double bonds, such as (meth)acryloyl groups or vinyl groups. By using other copolymer monomers (a4), the adhesiveness and heat resistance of the adhesive layer can be improved. Other copolymer monomers (a4) may be used alone or in combination.

[0129] The adhesion of the adhesive layer can be improved by using an amino group-containing monomer or an amide group-containing monomer as other copolymer monomers (a4). Examples of amino group-containing monomers are N,N-dimethylaminoethyl (meth)acrylate and N,N-dimethylaminopropyl (meth)acrylate. The amide group-containing monomers are, for example, acrylamide-based monomers such as (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-methylol-N-propane(meth)acrylamide, aminomethyl(meth)acrylamide, aminoethyl(meth)acrylamide, mercaptomethyl(meth)acrylamide, mercaptoethyl(meth)acrylamide, etc.; N-acryloyl heterocyclic monomers such as N-(meth)acryloylmorpholine, N-(meth)acryloylpiperidine, N-(meth)acryloylpyrrolidine, etc. It is an N-vinyl group-containing lactam monomer such as N-vinylpyrrolidone and N-vinyl-ε-caprolactam.

[0130] Other copolymer monomers (a4) may be polyfunctional monomers. By using polyfunctional monomers, the gel fraction of the adhesive layer and the cohesive force can be controlled. Polyfunctional monomers are, for example, polyfunctional acrylates such as 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)acrylate, dipentaerythritol hexa(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, allyl(meth)acrylate, vinyl(meth)acrylate, epoxy acrylate, polyester acrylate, urethane acrylate, etc.; and divinylbenzene. The polyfunctional acrylate is preferably 1,6-hexanediol diacrylate and dipentaerythritol hexa(meth)acrylate.

[0131] Other copolymer monomers (a4), in addition to those described above, include, for example, (meth)acrylate alkoxyalkyl esters such as (meth)acrylate 2-methoxyethyl, (meth)acrylate 2-ethoxyethyl, (meth)acrylate methoxytriethyleneglycol, (meth)acrylate 3-methoxypropyl, (meth)acrylate 3-ethoxypropyl, (meth)acrylate 4-methoxybutyl, (meth)acrylate 4-ethoxybutyl; cyclic polymerizable monomers such as 2-(allyloxymethyl)acrylate; epoxy group-containing monomers such as (meth)acrylate glycidyl, (meth)acrylate methylglycidyl; sulfonic acid group-containing monomers such as sodium vinylsulfonate; phosphate group-containing monomers; (Meth)acrylic acid esters having a hydrocyclic hydrocarbon group such as (meth)acrylate cyclopentyl, (meth)acrylate cyclohexyl, (meth)acrylate isobornyl; (meth)acrylic acid esters having an aromatic hydrocarbon group such as (meth)acrylate phenyl, (meth)acrylate phenoxyethyl, (meth)acrylate benzyl; vinyl esters such as vinyl acetate, vinyl propionate; aromatic vinyl compounds such as styrene, vinyltoluene; olefins or dienes such as ethylene, propylene, butadiene, isoprene, isobutylene; vinyl ethers such as vinylalkyl ethers; vinyl chloride may be used.

[0132] The content of other copolymer monomers (a4) in the (meth)acrylic polymer is preferably 20 mass% or less, more preferably 10 mass% or less, even more preferably 8 mass% or less, and particularly preferably 5 mass% or less.

[0133] 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, and more preferably 1.2 million to 2.5 million. When the weight-average molecular weight (Mw) is in this range, an adhesive layer with excellent durability (especially heat resistance) can be obtained. If the weight-average molecular weight (Mw) exceeds 3 million, an increase in viscosity and / or gelation during polymer polymerization may occur.

[0134] D-2-2. Silane coupling agents containing reactive functional groups

[0135] The adhesive composition may contain a silane coupling agent containing a reactive functional group. The reactive functional group in the silane coupling agent is typically a functional group other than an acid anhydride group. Examples of functional groups other than acid anhydrides include epoxy groups, mercapto groups, amino groups, isocyanate groups, isocyanurate groups, vinyl groups, styryl groups, acetoacetyl groups, ureido groups, thiourea groups, (meth)acrylic groups, heterocyclic groups, and combinations thereof. The silane coupling agent containing a reactive functional group may be used alone or in combination.

[0136] When a silane coupling agent containing a reactive functional group is incorporated into an adhesive composition, the amount of the silane coupling agent containing a reactive functional group is typically 0.001 parts by weight or more and 5 parts by weight or less per 100 parts by weight of (meth)acrylic polymer (A).

[0137] D-2-3. Crosslinking agent

[0138] The adhesive composition may contain a crosslinking agent. Organic crosslinking agents, polyfunctional metal chelates, etc. may be used as crosslinking agents. Examples of organic crosslinking agents include isocyanate-based crosslinking agents, peroxide-based crosslinking agents, epoxy-based crosslinking agents, and imine-based crosslinking agents. Polyfunctional metal chelates are formed in which a polyvalent metal is covalently or coordinately bonded to an organic compound. If the adhesive composition is of the radiation-curable type, polyfunctional monomers may be used as crosslinking agents. Crosslinking agents may be used alone or in combination.

[0139] When a crosslinking agent is incorporated into the adhesive composition, the amount of crosslinking agent incorporated is typically 0.01 parts by weight or more and 15 parts by weight or less per 100 parts by weight of (meth)acrylic polymer (A).

[0140] When an isocyanate-based crosslinking agent is incorporated into an adhesive composition, the amount of the isocyanate-based crosslinking agent incorporated is typically 0.01 parts by weight or more and 15 parts by weight or less per 100 parts by weight of the (meth)acrylic polymer.

[0141] When a peroxide is incorporated into an adhesive composition, the amount of peroxide incorporated is typically 0.01 parts by weight or more and 2 parts by weight or less per 100 parts by weight of a (meth)acrylic polymer. Within this range, it is easy to adjust processability and crosslinking stability.

[0142] D-2-4. Additives

[0143] The adhesive composition may contain (meth)acrylic oligomers and / or ionic compounds. Additionally, the adhesive composition may contain additives. Specific examples of additives include powders such as coloring agents and pigments, dyes, surfactants, plasticizers, tackifiers, surface lubricants, leveling agents, softeners, antioxidants, anti-aging agents, light stabilizers, UV absorbers, polymerization inhibitors, inorganic or organic fillers, metal powders, granular materials, and foil-like materials. Additionally, within a controllable range, a redox system with a reducing agent added may be adopted. The type, number, combination, and content of the additives can be appropriately set according to the purpose. The content of the additive is preferably 5 parts by weight or less, more preferably 3 parts by weight or less, and even more preferably 1 part by weight or less, per 100 parts by weight of the (meth)acrylic polymer (A).

[0144] E. Image display device

[0145] The polarizing plate with the phase difference layer and adhesive layer attached as described in claims A through D above can be applied to an image display device. Accordingly, embodiments of the present invention also include an image display device using such a polarizing plate with the phase difference layer and adhesive layer attached. Representative examples of image display devices include liquid crystal display devices and organic EL display devices. An image display device according to an embodiment of the present invention typically has a polarizing plate with the phase difference layer and adhesive layer attached as described in claims A through D above on its viewing side.

[0146] Examples

[0147] The present invention will be specifically described below by way of examples, but the present invention is not limited by these examples. In addition, the method for measuring each characteristic is as follows.

[0148] (1) Grass deviation amount

[0149] The polarizers with the phase difference layer and adhesive layer attached obtained in the examples and comparative examples were cut into a predetermined size (size M or size T in Table 1 described later) and used as test samples. The test samples were subjected to a heating test at 85°C for 500 hours, and after the heating test, the amount of the first adhesive layer protruding from the end surface of the polarizer and the phase difference layer was observed and measured using an objective lens (20x magnification). The length of the part with the largest protrusion of the first adhesive layer was defined as the full deviation amount. During observation, the transmitted light was set to 0 (zero) and the observation was adjusted to be performed using reflected light.

[0150] (2) Creep value

[0151] The polarizing plates with attached phase difference layers and adhesive layers obtained in the examples and comparative examples were cut into 10mm × 30mm pieces to serve as test samples. The upper 10mm × 10mm portion of the test sample was attached to a SUS plate with the second adhesive layer interposed therebetween, and a load of 500gf was applied vertically downward to the lower portion of the test sample. The amount of misalignment between the test sample and the SUS plate was measured 1 second and 3600 seconds after the load was applied, and Cr1 and Cr, respectively 3600 It was done as. Cr1 and Cr 3600 ΔCr, obtained from the following equation, was used as the creep value.

[0152] ΔCr=Cr 3600 -Cr1

[0153] (3) Color stain

[0154] The polarizers with the phase difference layer and adhesive layer attached obtained in the examples and comparative examples were cut to a predetermined size (size M or size T in Table 1 described later) and laminated onto a glass plate with the second adhesive layer interposed to prepare a test sample. The test sample, after heating at 85°C for 500 hours, was placed on a reflective sheet (manufactured by Toray Film Processor, DMS-deposited film), and the reflective color a of the central part of the sample was measured using a spectrophotometer (manufactured by Konica Minolta, product name 'CM-2600d'). * C and b * C Wow, the reflective color a at the end of the sample * E and b * E ...was measured. Δab, calculated from the following formula, was used as an indicator of color staining. A smaller Δab indicates better color staining.

[0155] Δab={(a * E -a * C ) 2 +(b * E -b * C )2} 1 / 2

[0156] [Abbreviation of compound]

[0157] The abbreviations of the compounds used in the following manufacturing examples are as follows.

[0158] ·BPFM: Bis[9-(2-phenoxycarbonylethyl)fluoren-9-yl]methane

[0159] It was synthesized by the method described in Japanese Patent Publication No. 2015-25111.

[0160]

[0161] ·ISB: Isosorbide [Manufactured by Rocket Fluresa]

[0162] ·SPG: Spiroglycol [Manufactured by Mitsubishi Gas Chemical Co., Ltd.]

[0163] ·DPC: Diphenyl carbonate [Manufactured by Mitsubishi Chemical Corporation]

[0164] [Preparation Example 1: Preparation of a phase difference film constituting a phase difference layer]

[0165] Polymerization was carried out using a batch polymerization apparatus comprising two vertical stirred reactors equipped with stirring blades and reflux condensers. 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 × 10⁻⁶ calcium acetate monohydrate as a catalyst. -4 Mass part (4.47×10⁻⁶ -6(mol) was added. After vacuuming the reactor with nitrogen, heating was performed using a heat medium, and stirring was initiated when the internal temperature reached 100°C. Forty minutes after the start of the heating process, the internal temperature was raised to 220°C, and while controlling the temperature to maintain this level, vacuuming was initiated; the pressure was reduced to 13.3 kPa 90 minutes after reaching 220°C. The phenol vapor produced as a byproduct of the polymerization reaction was directed to a reflux condenser at 110°C, and the monomer components contained in a small amount of the phenol vapor were returned to the reactor. The phenol vapor that did not condense was directed to a condenser at 45°C and recovered. Nitrogen was introduced into the first reactor to increase the pressure to atmospheric pressure, and then the oligomerized reaction liquid in the first reactor was transferred to the second reactor. Subsequently, heating and vacuuming were initiated in the second reactor, and the internal temperature was set to 240°C and the pressure to 20 kPa after 40 minutes. Subsequently, polymerization was carried out while further reducing the pressure until a predetermined stirring power was reached. Upon reaching the predetermined power, nitrogen was introduced into the reactor to apply pressure, the resulting polyester carbonate was extruded into water, and the strands were cut to obtain pellets. This resin is referred to as 'PC1'. The ratio of structural units derived from each monomer is BPFM / ISB / SPG / DPC = 21.5 / 39.4 / 30.0 / 9.1 mass%. The reduced viscosity of PC1 is 0.46 dL / g, Mw is 48,000, and the refractive index (n D ) is 1.526, melt viscosity is 2480 Pa·s, glass transition temperature is 139℃, and photoelastic modulus is 9×10 -12 [m 2 / N], wavelength dispersion Re(450) / Re(550) was 0.85.

[0166] Extrusion mixing was performed with polyester carbonate obtained using Dianale BR80 (manufactured by Mitsubishi Chemical Corporation) as an acrylic resin. A mixture of polycarbonate pellets (99.5 parts by mass) and BR80 powder (0.5 parts by mass) was fed into a twin-screw extruder TEX30HSS manufactured by Nippon Steel Corporation using a metering feeder. The extruder cylinder temperature was set to 250°C, and extrusion was performed at a throughput of 12 kg / hr and a screw rotation speed of 120 rpm. In addition, the extruder was equipped with a vacuum vent, and the molten resin was extruded while degassing under reduced pressure. After vacuum drying the pellets of the resin composition obtained in this way at 100°C for more than 6 hours, a long unoriented film with a length of 3 m, a width of 200 mm, and a thickness of 100 μm was produced using a film making device equipped with a single-screw extruder (manufactured by Isuzu Chemical Engineering Co., Ltd., screw diameter 25 mm, cylinder set temperature: 250°C), a T-die (width 300 mm, set temperature: 220°C), a chilled roll (set temperature: 120~130°C), and a winder. This long unoriented film was stretched at a stretching temperature of Tg and a stretching ratio of 2.4 times. The obtained stretched film was subjected to a relaxation treatment (relaxation temperature 130°C, relaxation rate 4.5%) and then subjected to a heat treatment at 125°C for 2 minutes.

[0167] In this way, a phase difference film R1 constituting a phase difference layer was obtained. When the phase difference film R1 was heated at 125°C for 180 minutes, the shrinkage rate in the ground axis direction was 2.92%. In addition, the phase difference film R1 exhibited refractive index characteristics of nx > ny > nz, Re(550) was 145 nm, and Re(450) / Re(550) was 0.85.

[0168] [Preparation Example 2: Preparation of a phase difference film constituting a phase difference layer]

[0169] Phase difference film R2 was obtained in the same manner as in Preparation Example 1, except that relaxation treatment and heat treatment were not performed. When the phase difference film R2 was heated at 125°C for 180 minutes, the shrinkage rate in the ground axis direction was 4.54%. In addition, the phase difference film R2 exhibited refractive index characteristics of nx > ny > nz, Re(550) was 145 nm, and Re(450) / Re(550) was 0.85.

[0170] [Preparation Example 3: Preparation of Adhesive]

[0171] (Preparation of acrylic polymer A1)

[0172] A monomer mixture containing 99 parts of butyl acrylate and 1 part of 4-hydroxybutyl acrylate was added to a 4-neck flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser. Additionally, 0.1 parts of 2,2'-azobisisobutyronitrile was added as a polymerization initiator along with 100 parts of ethyl acetate to 100 parts of this monomer mixture. After introducing nitrogen gas while gently stirring to achieve nitrogen purging, the liquid temperature inside the flask was maintained at around 55°C and the polymerization reaction was carried out for 8 hours to prepare a solution of acrylic polymer A1 having a weight-average molecular weight (Mw) of 1.8 million and Mw / Mn = 4.8.

[0173] (Preparation of adhesive)

[0174] Adhesive PSA1 was obtained by mixing 0.02 parts of a trimethylolpropane / xylylene diisocyanate adduct (manufactured by Tosho Co., Ltd., trade name 'Takenate D110N'), 0.3 parts of a peroxide crosslinking agent (manufactured by Nippon Yuji Co., Ltd., trade name 'Niper BMT'), and 0.2 parts of an epoxy group-containing silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name 'KBM-403') with respect to 100 parts of the solid content of an acrylic polymer A1 solution.

[0175] [Preparation Example 4: Preparation of Adhesive]

[0176] Adhesive PSA2 was obtained in the same manner as in Preparation Example 3, except that the amount of D110N was changed to 0.1 parts.

[0177] [Preparation Example 5: Preparation of Adhesive]

[0178] (Preparation of acrylic polymer A2)

[0179] A solution of acrylic polymer A2 with Mw 230,000 and Mw / Mn=3.9 was prepared in the same manner as in Preparation Example 3, except that a monomer mixture containing 94.9 parts butyl acrylate, 0.1 parts 2-hydroxyethyl acrylate, and 5 parts acrylic acid was used.

[0180] (Preparation of adhesive)

[0181] Adhesive PSA3 was obtained by mixing 0.6 parts of a trimethylolpropane / tolylene diisocyanate adduct (manufactured by Tosho Co., Ltd., trade name 'Colonate L'), 0.2 parts of a peroxide crosslinking agent (manufactured by Nippon Yuji Co., Ltd., trade name 'Niper BMT'), and 0.2 parts of an epoxy group-containing silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name 'KBM-403') with respect to 100 parts of the solid content of an acrylic polymer A2 solution.

[0182] [Preparation Example 6: Preparation of Adhesive]

[0183] (Preparation of acrylic polymer A3)

[0184] A solution of acrylic polymer A3 with Mw 2.7 million and Mw / Mn=3.8 was prepared in the same manner as in Preparation Example 3, except that a monomer mixture containing 91 parts butyl acrylate, 6 parts N-acryloylmorpholine, 0.3 parts 4-hydroxybutyl acrylate, and 2.7 parts acrylic acid was used.

[0185] (Preparation of adhesive)

[0186] Adhesive PSA4 was obtained by mixing 0.1 parts of a trimethylolpropane / tolylene diisocyanate adduct (manufactured by Tosho Co., Ltd., trade name 'Colonate L'), 0.3 parts of a peroxide crosslinking agent (manufactured by Nippon Yuji Co., Ltd., trade name 'Niper BMT'), and 0.2 parts of an epoxy group-containing silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name 'KBM-403') with respect to 100 parts of the solid content of an acrylic polymer A3 solution.

[0187] [Preparation Example 7: Preparation of Adhesive]

[0188] (Preparation of acrylic polymer A4)

[0189] A solution of acrylic polymer A4 with an Mw of 2.2 million was prepared in the same manner as in Preparation Example 3, except that a monomer mixture containing 82.1 parts butyl acrylate, 13 parts benzyl acrylate, 0.1 parts 4-hydroxybutyl acrylate, and 4.8 parts acrylic acid was used.

[0190] (Preparation of adhesive)

[0191] Adhesive PSA5 was obtained by combining 0.5 parts of a polyether compound having a reactive silyl group (manufactured by Kaneka, trade name 'Cylyl SAT10'), 0.45 parts of a trimethylolpropane / tolylene diisocyanate adduct (manufactured by Tosho, trade name 'Colonate L'), and 0.1 parts of a peroxide crosslinking agent (benzoyl peroxide) with respect to 100 parts of the solid content of an acrylic polymer A4 solution.

[0192] [Preparation Example 8: Preparation of a Polarizing Plate]

[0193] (Fabrication of a polarizer)

[0194] A polarizer with a thickness of 12 μm was produced by uniaxially stretching a long roll of a polyvinyl alcohol (PVA) resin film (manufactured by Kuraray, product name 'PE3000') with a thickness of 30 μm in the long direction by a roll stretching machine to a length of 5.9 times, while simultaneously performing swelling, dyeing, crosslinking, and washing treatments, and finally performing a drying treatment.

[0195] Specifically, the swelling treatment was performed by stretching the material 2.2 times while using pure water at 20°C. Subsequently, the dyeing treatment was performed by stretching the material 1.4 times while using an aqueous solution at 30°C with a weight ratio of iodine to potassium iodide of 1:7, in which the iodine concentration was adjusted so that the single transmittance of the resulting polarizer was 45.0%. In addition, a two-stage crosslinking treatment was employed, and the first stage crosslinking treatment was performed by stretching the material 1.2 times while using an aqueous solution of dissolved boric acid and potassium iodide at 40°C. The boric acid content of the aqueous solution for the first stage crosslinking treatment was 5.0 wt%, and the potassium iodide content was 3.0 wt%. The second stage crosslinking treatment was performed by stretching the material 1.6 times while using an aqueous solution of dissolved boric acid and potassium iodide at 65°C. The boric acid content of the aqueous solution for the second crosslinking treatment was set to 4.3 wt%, and the potassium iodide content was set to 5.0 wt%. Additionally, the washing treatment was performed using an aqueous potassium iodide solution at 20°C. The potassium iodide content of the aqueous solution for the washing treatment was set to 2.6 wt%. Finally, the polarizer was obtained by drying at 70°C for 5 minutes.

[0196] (Fabrication of polarizing plates)

[0197] A polarizing plate P1 having a protective layer / polarizing plate configuration was obtained by interposing a polyvinyl alcohol-based adhesive on one side of the above polarizer and laminating a triacetylcellulose film (thickness 40 μm, manufactured by Konica Minolta, trade name 'KC4UYW').

[0198] [Preparation Example 9: Preparation of a Polarizing Plate]

[0199] (Fabrication of a polarizer)

[0200] Corona treatment was performed on one side of a resin substrate using an amorphous isophthal copolymer polyethylene terephthalate film (thickness: 100 μm) which is long in shape and has a Tg of about 75°C as a thermoplastic resin substrate.

[0201] A PVA aqueous solution (coating solution) was prepared by adding 13 parts by weight of potassium iodide to 100 parts by weight of a PVA-based resin mixed in a 9:1 ratio of polyvinyl alcohol (degree of polymerization 4200, degree of saponification 99.2 mol%) and acetoacetyl-modified PVA (manufactured by Nihon Synthetic Chemical Industry Co., Ltd., trade name 'Gosepamer') and dissolving it in water.

[0202] A laminate was produced by applying the above PVA aqueous solution to the corona-treated surface of a resin substrate and drying it at 60°C to form a PVA-based resin layer with a thickness of 13 μm.

[0203] The obtained laminate was uniaxially stretched 2.4 times in the longitudinal direction (long direction) in an oven at 130°C (air-assisted stretching treatment).

[0204] Next, the laminate was immersed for 30 seconds in an insolubilization bath at a liquid temperature of 40°C (an aqueous boric acid solution obtained by mixing 4 parts by weight of boric acid with 100 parts by weight of water) (insolubilization treatment).

[0205] Next, the polarizer was immersed for 60 seconds in a dyeing bath at a liquid temperature of 30°C (an aqueous iodine solution obtained by mixing iodine and potassium iodide in a weight ratio of 1:7 with respect to 100 parts by weight of water) while adjusting the concentration so that the final obtained elemental transmittance (Ts) of the polarizer becomes a desired value (dyeing treatment).

[0206] Next, it was immersed for 30 seconds in a crosslinking bath at a liquid temperature of 40°C (an aqueous boric acid solution obtained by mixing 3 parts by weight of potassium iodide and 5 parts by weight of boric acid with 100 parts by weight of water) (crosslinking treatment).

[0207] Afterwards, the laminate was immersed in an aqueous boric acid solution (boric acid concentration 4 wt%, potassium iodide concentration 5 wt%) at a liquid temperature of 70°C, and uniaxial stretching was performed in the longitudinal direction (long direction) between rolls with different circumferential speeds such that the total stretching ratio was 5.5 times (underwater stretching treatment).

[0208] Afterwards, the laminate was immersed in a cleaning bath at a liquid temperature of 20°C (an aqueous solution obtained by mixing 4 parts by weight of potassium iodide with 100 parts by weight of water) (cleaning treatment).

[0209] Afterwards, while drying in an oven maintained at approximately 90°C, it was brought into contact with a SUS heating roll maintained at a surface temperature of approximately 75°C (drying shrinkage treatment).

[0210] In this way, a polarizer with a thickness of about 5 μm was formed on a resin substrate, and a polarizing plate having the configuration of a resin substrate / polarizer was obtained.

[0211] (Fabrication of polarizing plates)

[0212] A cycloolefin-based film (manufactured by Nippon Zeon, ZF-12, 23 μm) as a protective layer was laminated onto the surface of the obtained polarizer (the side opposite to the resin substrate) with a UV-curing adhesive interposed therebetween. Specifically, the adhesive was coated to a total thickness of approximately 1.0 μm and laminated using a roller machine. Subsequently, UV light was irradiated from the cycloolefin-based film side to cure the adhesive. Then, the resin substrate was peeled off to obtain a polarizing plate P2 having the configuration of a cycloolefin-based film (protective layer) and a polarizer.

[0213] [Examples 1–5 and Comparative Examples 1–8]

[0214] A polarizing plate, a phase difference film (phase difference layer), and an adhesive (first adhesive layer and second adhesive layer) were combined as shown in Table 1 to fabricate a polarizing plate with a phase difference layer and an adhesive layer attached. Here, the polarizing plate and the phase difference layer (phase difference film) were laminated such that the absorption axis of the polarizer and the ground axis of the phase difference film formed an angle of 45°. The obtained polarizing plate with the phase difference layer and the adhesive layer attached was provided for the evaluation of the color stain. The results, along with the amount of glue misalignment of the first adhesive layer, the shrinkage rate of the phase difference layer, and the creep value of the second adhesive layer, are shown in Table 1. Additionally, in the 'Size' column of Table 1, 'M' refers to a size of 77.4 mm × 162.3 mm, and 'T' refers to a size of 159.5 mm × 244.5 mm.

[0215]

[0216] [evaluation]

[0217] As is clear from Table 1, by controlling the amount of adhesive misalignment of the first adhesive layer, the shrinkage rate of the phase difference layer, and the creep value of the second adhesive layer in combination, it can be seen that a polarizing plate with attached phase difference layer and adhesive layer can be obtained, which enables the realization of an image display device with suppressed color stains in a high-temperature environment.

[0218] [Industrial Applicability]

[0219] The polarizing plate with the phase difference layer and adhesive layer attached according to the present invention can be suitably used in an image display device (typically a liquid crystal display device, an organic EL display device). Explanation of the symbols

[0220] 10: Polarizer 11: Polarizer 12: First protective layer 13: Second protective layer 20: First adhesive layer 30: Phase difference layer 40: Second adhesive layer 100: Polarizing plate with phase difference layer and adhesive layer attached

Claims

Claim 1 A polarizing plate including a polarizer, a retardation layer laminated on the polarizing plate via a first adhesive layer, and a second adhesive layer provided as an outermost layer on the side opposite to the polarizing plate of the retardation layer, wherein the retardation layer is composed of a stretched film of a resin film, satisfies the relationship of Re(450) < Re(550), and has a shrinkage rate in the direction of the slow axis of 4% or less when heated at 80°C to 125°C for up to 180 minutes. At this time, Re(450) and Re(550) are the in-plane retardations measured with light of wavelengths 450 nm and 550 nm at 23°C, respectively. The peeling amount of the first adhesive layer after a heating test at 85°C for 500 hours is 300 µm or more, the retardation layer includes at least one bonding group selected from the group consisting of a carbonate bond and an ester bond, and at least one structural unit selected from the group consisting of a structural unit represented by the following general formula (1) and a structural unit represented by the following general formula (2), and is a resin having positive refractive index anisotropy; and contains an acrylic resin, the content of the acrylic resin is 0.5 mass% to 2.0 mass%, the acrylic resin contains 70 mass% or more of a structural unit derived from methyl methacrylate, and its weight average molecular weight (Mw) is 10,000 to 200,000, a retardation layer and adhesive layer-attached polarizing plate: In general formulas (1) and (2), R 1 ~R 3 are each independently a direct bond, a substituted or unsubstituted alkylene group having 1 to 4 carbon atoms, and R 4 ~R 9 Each is independently a hydrogen atom, a substituted or unsubstituted C1-10 alkyl group, a substituted or unsubstituted C4-10 aryl group, a substituted or unsubstituted C1-10 acyl group, a substituted or unsubstituted C1-10 alkoxy group, a substituted or unsubstituted C1-10 aryloxy group, a substituted or unsubstituted amino group, a substituted or unsubstituted C1-10 vinyl group, a substituted or unsubstituted C1-10 ethenyl group, a sulfur atom having a substituent, a silicon atom having a substituent, a halogen atom, a nitro group, or a cyano group; provided, R 4 ~R 9 They may be identical or different, and R 4 ~R 9 At least two adjacent groups can combine to form a ring. Claim 2 A polarizing plate with a phase difference layer and an adhesive layer attached, wherein the Re (550) of the phase difference layer is 100 nm to 200 nm and the angle formed by the ground axis of the phase difference layer and the absorption axis of the polarizer is 40° to 50° or 130° to 140°. Claim 3 A polarizing plate with a phase difference layer and an adhesive layer attached, wherein the thickness of the phase difference layer is 15㎛ to 60㎛ in claim 1 or 2. Claim 4 A polarizing plate with a phase difference layer and an adhesive layer attached, wherein, in claim 1 or 2, the stretched film constituting the phase difference layer is subjected to a heat treatment of heating at a temperature of 105°C or higher for 2 minutes or more. Claim 5 A polarizing plate having a phase difference layer and an adhesive layer attached, wherein, in claim 1 or 2, another phase difference layer between the phase difference layer and the second adhesive layer exhibits a refractive index characteristic of nz > nx = ny. Claim 6 delete Claim 7 An image display device having a polarizing plate with a phase difference layer and an adhesive layer attached as described in claim 1 or 2.

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