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

Abstract

This invention provides a polarizer with a phase retardation layer and an adhesive layer for an image display device that suppresses phase retardation, color retardation, and light leakage in high-temperature environments. The polarizer with a phase retardation layer and an adhesive layer according to embodiments of this invention comprises: a polarizer including a polarizing mirror, a phase retardation layer bonded to the polarizer via a first adhesive layer, and a second adhesive layer disposed as the outermost layer on the side opposite to the polarizer of the phase retardation layer. The phase retardation layer is formed from a stretched film of a resin film and satisfies the relationship Re(450) < Re(550). The paste offset of the first adhesive layer after a heating test at 85°C for 500 hours is 900 μm or less, and the creep value of the second adhesive layer at 85°C is 40 μm or less.

Description

Technical Field

[0001] This invention relates to a polarizer with a phase retardation layer and an adhesive layer, and an image display device using the polarizer with the phase retardation layer and adhesive layer. Background Technology

[0002] In recent years, image display devices, represented by liquid crystal displays and electroluminescent (EL) displays (e.g., organic EL displays and inorganic EL displays), have become increasingly popular. Polarizers and retardation plates are typically used in image display devices. In practical applications, polarizers with a retardation layer, which integrate the polarizer and retardation plate, are widely used (e.g., Patent Document 1). However, polarizers with a retardation layer can experience phase difference inconsistencies at high temperatures, resulting in color inconsistencies and light leakage in image display devices at high temperatures.

[0003] Existing technical documents

[0004] Patent documents

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

[0006] The problem that the invention aims to solve

[0007] The present invention was made to solve the above-mentioned existing problems, and its main objective is to provide a polarizer with a phase difference layer and an adhesive layer for an image display device that can suppress phase difference unevenness, color unevenness and light leakage in high temperature environments.

[0008] Problem Solving Methods

[0009] The polarizer with a phase retardation layer and an adhesive layer according to an embodiment of the present invention comprises: a polarizer including a polarizing mirror, a phase retardation layer attached to the polarizer via a first adhesive layer, and a second adhesive layer disposed as the outermost layer on the side opposite to the polarizer of the phase retardation layer. The phase retardation layer is formed from a stretched film of a resin film and satisfies the relationship Re(450) < Re(550). The paste offset of the first adhesive layer after a heating test at 85°C for 500 hours is less than 900 μm, and the creep value of the second adhesive layer at 85°C is less than 40 μm. Re(450) and Re(550) are the in-plane phase differences measured at 23°C with wavelengths of 450 nm and 550 nm, respectively.

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

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

[0012] In one embodiment, the paste offset of the first adhesive layer after a heating test at 85°C for 500 hours is less than 250 μm.

[0013] In one embodiment, the adhesive composition constituting the second adhesive layer comprises 1.5 parts by weight or more of a crosslinking agent relative to 100 parts by weight of the base polymer.

[0014] In one embodiment, the adhesive composition constituting the second adhesive layer comprises 5 or more parts by weight of a crosslinking agent relative to 100 parts by weight of the base polymer.

[0015] In one embodiment, the polarizer with the phase retardation layer and the adhesive layer further has an additional phase retardation layer between the phase retardation layer and the second adhesive layer, the refractive index characteristics of which show a relationship of nz > nx = ny.

[0016] In one embodiment, the phase retardation layer comprises an acrylic resin and a resin having positive refractive index anisotropy. The acrylic resin content is 0.5% to 2.0% by mass, the acrylic resin contains at least 70% by mass of structural units derived from methyl methacrylate, and its weight-average molecular weight Mw is 10,000 to 200,000. The resin having positive refractive index anisotropy comprises at least one bonding group selected from carbonate bonds and ester bonds, and at least one structural unit selected from the structural units represented by the following general formula (1) and the following general formula (2).

[0017] [Chemical Formula 1]

[0018]

[0019] [Chemical Formula 2]

[0020]

[0021] In 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, R 4 ~R 9Each of the following groups is independently a hydrogen atom, an alkyl group with 1 to 10 substituted or unsubstituted carbon atoms, an aryl group with 4 to 10 substituted or unsubstituted carbon atoms, an acyl group with 1 to 10 substituted or unsubstituted carbon atoms, an alkoxy group with 1 to 10 substituted or unsubstituted carbon atoms, an aryloxy group with 1 to 10 substituted or unsubstituted carbon atoms, an amino group with 1 to 10 substituted or unsubstituted carbon atoms, an ethynyl group with 1 to 10 substituted or unsubstituted carbon atoms, a sulfur atom having a substituent, a silicon atom having a substituent, a halogen atom, a nitro group, or a cyano group, and R 4 ~R 9 R can be either the same or different from each other. 4 ~R 9 At least two adjacent groups may optionally bond to each other to form a ring.

[0022] In one embodiment, during a humidification TMA test in which the environment was changed in the order of 25°C / 50%RH, 60°C / 50%RH, and 60°C / 85%RH, the dimensional change rate of the aforementioned phase difference layer in the slow axis direction was less than 0.28%.

[0023] In one embodiment, during a humidification TMA test in which the environment was changed in the order of 25°C / 50%RH, 60°C / 50%RH, and 60°C / 85%RH, the dimensional change rate of the phase difference layer in the slow axis direction was less than 0.28% when the additional phase difference layer was attached.

[0024] According to other aspects of the present invention, an image display device may be provided. This image display device includes the polarizer described above with a phase retardation layer and an adhesive layer.

[0025] The effects of the invention

[0026] According to an embodiment of the present invention, by combining and optimizing the paste offset of the adhesive layer between the polarizer and the phase retardation layer and the creep value of the adhesive layer used to bond the polarizer with the phase retardation layer and adhesive layer to the image display unit in a polarizer with a phase retardation layer and adhesive layer, it is possible to realize a polarizer with a phase retardation layer and adhesive layer in which phase difference unevenness is suppressed in a high-temperature environment. As a result, an image display device in which color unevenness and light leakage are suppressed in a high-temperature environment can be realized. Attached Figure Description

[0027] Figure 1 This is a cross-sectional schematic diagram of a polarizer with a phase difference layer and an adhesive layer according to one embodiment of the present invention.

[0028] Symbol Explanation

[0029] 10 Polarizing filters

[0030] 11. Polarizing mirror

[0031] 12 First protective layer

[0032] 13 Second protective layer

[0033] 20 First adhesive layer

[0034] 30 phase difference layers

[0035] 40 Second adhesive layer

[0036] 100 Polarizers with Phase Retardation Layer and Adhesive Layer Detailed Implementation

[0037] The following describes representative embodiments of the present invention, but the present invention is not limited to these embodiments.

[0038] (Definitions of terms and symbols)

[0039] The terms and symbols used in this manual are defined as follows.

[0040] (1) Refractive index (nx, ny, nz)

[0041] “nx” is the refractive index in the direction where the refractive index reaches its maximum in the plane (i.e., the slow axis direction), “ny” is the refractive index in the direction orthogonal to the slow axis in the plane (i.e., the fast axis direction), and “nz” is the refractive index in the thickness direction.

[0042] (2) In-plane phase difference (Re)

[0043] “Re(λ)” is the in-plane phase difference of the film measured at 23°C with light of wavelength λnm. For example, “Re(450)” is the in-plane phase difference of the film measured at 23°C with light of wavelength 450nm. When the thickness of the film is set as d (nm), Re(λ) can be obtained by the formula: Re=(nx-ny)×d.

[0044] (3) Phase difference (Rth) in the thickness direction

[0045] “Rth(λ)” is the phase difference along the thickness direction of the film measured at 23°C using light with a wavelength of λnm. For example, “Rth(450)” is the phase difference along the thickness direction of the film measured at 23°C using light with a wavelength of 450nm. When the thickness of the film is set as d (nm), Rth(λ) can be obtained using the formula: Rth=(nx-nz)×d.

[0046] (4) Nz coefficient

[0047] The coefficient of Nz can be obtained by Nz = Rth / Re.

[0048] (5) Angle

[0049] In this instruction manual, when referring to angles, unless otherwise specified, the angles include both clockwise and counterclockwise angles.

[0050] A. Overall structure of a polarizer with a phase retardation layer and an adhesive layer

[0051] Figure 1 This is a cross-sectional schematic diagram of a polarizer with a phase retardation layer and an adhesive layer according to an embodiment of the present invention. The polarizer 100 with a phase retardation layer and an adhesive layer shown in the figure includes: a polarizer 10, a phase retardation layer 30 bonded to the polarizer 10 via a first adhesive layer 20, and a second adhesive layer 40 disposed as the outermost layer on the side of the phase retardation layer 30 opposite to the polarizer 10. Using the second adhesive layer 40, the polarizer with the phase retardation layer and adhesive layer can be adhered to an image display unit. The polarizer 10 includes: a polarizer 11, a first protective layer 12 disposed on one side of the polarizer 11, and a second protective layer 13 disposed on the other side of the polarizer 11. Depending on the purpose, one of the first protective layer 12 and the second protective layer 13 may be omitted. For example, the phase retardation layer 30 may also function as a protective layer for the polarizer 11; therefore, the second protective layer 13 may also be omitted. The angle between the slow axis of the phase difference layer 30 and the absorption axis of the polarizer 11 is preferably 40° to 50°, more preferably 42° to 48°, further preferably 44° to 46°, and particularly preferably about 45°; or, preferably 130° to 140°, more preferably 132° to 138°, further preferably 134° to 136°, and particularly preferably about 135°.

[0052] The retardation layer 30 is formed by stretching a resin film and satisfies the relationship Re(450) < Re(550). The Re(550) of the retardation layer 30 is typically 100 nm to 200 nm. The paste offset of the first adhesive layer 20 after a heating test at 85°C for 500 hours is less than 900 μm, and the creep value of the second adhesive layer 40 at 85°C is less than 40 μm. The details of each layer constituting the polarizer with the retardation layer and the adhesive layer are described later.

[0053] In one embodiment, the polarizer with the retardation layer and the adhesive layer may further have an additional retardation layer (not shown) between the retardation layer 30 and the second adhesive layer 40. Typically, the refractive index characteristics of the additional retardation layer show a relationship of nz > nx = ny. By providing such an additional retardation layer, reflections in the tilt direction can be effectively prevented, and a wide viewing angle with anti-reflective function can be achieved.

[0054] In one embodiment, the polarizer with a phase retardation layer and an adhesive layer may further have a conductive layer or an isotropic substrate (not shown) with a conductive layer. When a conductive layer or an isotropic substrate with a conductive layer is provided, the polarizer with a phase retardation layer and an adhesive layer can be used in a so-called embedded touch panel type input display device in which a touch sensor is introduced between an image display unit (e.g., an organic EL unit) and the polarizer. The conductive layer or isotropic substrate with a conductive layer is typically disposed between the phase retardation layer 30 and the second adhesive layer 40. When an additional phase retardation layer is provided, typically, an additional phase retardation layer and a conductive layer or isotropic substrate with a conductive layer can be sequentially disposed from the phase retardation layer 30 side.

[0055] Polarizers with a retardation layer and an adhesive layer may also have a further retardation layer (not shown). The further retardation layer may be combined with another retardation layer or may be provided alone (i.e., without another retardation layer). The optical properties (e.g., refractive index characteristics, in-plane phase difference, Nz coefficient, photoelastic coefficient), thickness, and placement of the further retardation layer may be appropriately set according to the purpose.

[0056] The polarizer with a phase retardation layer and an adhesive layer can be in sheet form or in strip form. In this specification, "strip form" refers to an elongated shape whose length is sufficiently long relative to its width, for example, including elongated shapes whose length is more than 10 times, preferably more than 20 times, the width. The strip-shaped polarizer with a phase retardation layer and an adhesive layer can be wound into a roll.

[0057] In practical applications, it is preferable to temporarily attach a release film to the surface of the second adhesive layer 40 until the polarizer with the phase retardation layer and adhesive layer is put into use. By temporarily attaching the release film, the second adhesive layer can be protected, and a roll of polarizer with the phase retardation layer and adhesive layer can be formed.

[0058] The following describes the constituent elements of a polarizer with a phase retardation layer and an adhesive layer.

[0059] B. Polarizing filter

[0060] As the polarizer 11, any suitable polarizer can be used. For example, the resin film forming the polarizer can be a single-layer resin film or a laminate of two or more layers.

[0061] Specific examples of polarizers composed of single-layer resin films include polarizers made by dyeing and stretching hydrophilic polymer films such as polyvinyl alcohol (PVA) films, partially formalized PVA films, and partially saponified ethylene-vinyl acetate copolymer films using dichroic substances such as iodine and dichroic dyes; and polyene-oriented films such as dehydrated PVA products and dehydrochlorinated polyvinyl chloride products. Due to their excellent optical properties, polarizers obtained by dyeing PVA films with iodine and then uniaxially stretching them are preferred.

[0062] The aforementioned iodine-based dyeing can be performed, for example, by immersing the PVA film in an aqueous iodine solution. The preferred stretching ratio for the uniaxial stretching is 3 to 7 times. Stretching can be performed after dyeing or simultaneously with dyeing. Alternatively, dyeing can be performed after stretching. The PVA film can be subjected to swelling treatment, cross-linking treatment, cleaning treatment, drying treatment, etc., as needed. For example, by immersing the PVA film in water for washing before dyeing, not only can dirt and anti-blocking agents on the surface of the PVA film be cleaned, but the PVA film can also swell to prevent uneven dyeing.

[0063] As specific examples of polarizers obtained using laminates, examples include polarizers obtained using a resin substrate and a PVA-type resin layer (PVA-type resin film) laminated on the resin substrate, or polarizers obtained using a resin substrate and a laminate coated with a PVA-type resin layer formed on the resin substrate. Polarizers obtained using a laminate of a resin substrate and a PVA-type resin layer coated on the resin substrate can be manufactured by, for example, coating a PVA-type resin solution onto a resin substrate, allowing it to dry to form a PVA-type resin layer on the resin substrate, thus obtaining a laminate of the resin substrate and the PVA-type resin layer; stretching and dyeing the laminate to form a polarizer from the PVA-type resin layer. In this embodiment, stretching typically includes immersing the laminate in an aqueous boric acid solution for stretching. Furthermore, stretching may, as needed, further include stretching the laminate in a gas atmosphere at a high temperature (e.g., above 95°C) before stretching in the aqueous boric acid solution. The resulting resin substrate / polarizer laminate can be used directly (i.e., the resin substrate is used as a protective layer for the polarizer), or the resin substrate can be peeled off from the resin substrate / polarizer laminate, and any suitable protective layer corresponding to the purpose can be laminated on the peeled surface for use. Detailed descriptions of such a polarizer manufacturing method are provided, for example, in Japanese Patent Application Publication No. 2012-73580 and Japanese Patent No. 6470455. The descriptions in these patent documents are incorporated herein by reference.

[0064] The polarizer is preferably made of a single-layer resin film. With such a configuration, a polarizer with a phase difference layer and an adhesive layer can be obtained, based on the optimized synergistic effect with the first adhesive layer and the second adhesive layer, where phase difference non-uniformity is suppressed in high-temperature environments.

[0065] The thickness of the polarizer is preferably 15 μm or less, more preferably 1 μm to 12 μm, and even more preferably 3 μm to 12 μm. If the thickness of the polarizer is within this range, curling during heating can be well suppressed, and good appearance durability during heating can be obtained.

[0066] Furthermore, the thickness of the polarizer is particularly preferably 8 μm or less. If the thickness of the polarizer is below this upper limit, it is possible to suppress the peeling of the polarizer with the phase retardation layer and the adhesive layer from the adhered object in a high humidity environment, as well as the formation of bubbles in the adhesive layer.

[0067] The polarizer preferably exhibits absorption dichroism at any wavelength within the range of 380 nm to 780 nm. The single-unit transmittance of the polarizer is, for example, 41.5% to 46.0%, preferably 43.0% to 46.0%, more preferably 44.5% to 46.0%. The degree of polarization of the polarizer is preferably 97.0% or more, more preferably 99.0% or more, and even more preferably 99.9% or more.

[0068] C. Protective layer

[0069] The first protective layer 12 and the second protective layer 13 can each be formed from any suitable film that can be used as a protective layer for a polarizer. Specific examples of materials that are the main components of the film include: cellulose resins such as cellulose triacetate (TAC), polyesters, polyvinyl alcohols, polycarbonates, polyamides, polyimides, polyethersulfones, polysulfones, polystyrene, polynorbornene, polyolefins, (meth)acrylic acids, acetates, and other transparent resins. Additionally, thermosetting resins or UV-curing resins such as (meth)acrylic acids, urethanes, (meth)acrylate urethanes, epoxy resins, and silicone resins can also be used. Furthermore, glassy polymers such as siloxane polymers can also be used. Alternatively, polymer films described in Japanese Patent Application Publication No. 2001-343529 (WO01 / 37007) can also be used. As the material for this membrane, resin compositions can be used, for example, thermoplastic resins containing substituted or unsubstituted imide groups on the side chains, and thermoplastic resins containing substituted or unsubstituted phenyl and nitrile groups on the side chains. Examples include resin compositions having alternating copolymers formed from isobutylene and N-methylmaleimide, and acrylonitrile-styrene copolymers. The polymer membrane can be, for example, an extruded product of the above-mentioned resin compositions.

[0070] As described below, a polarizer with a phase retardation layer and an adhesive layer can typically be disposed on the viewable side of an image display device, and a first protective layer 12 can typically be disposed on its viewable side. Therefore, as needed, the first protective layer 12 can undergo surface treatments such as hard coating, anti-reflective treatment, anti-adhesion treatment, and anti-glare treatment. Further / or, the first protective layer 12 can be treated to improve visual recognition when viewed through polarized glasses (typically by imparting (elliptical) polarization or ultra-high phase retardation). By implementing such treatment, excellent visual recognition can be achieved even when viewing the displayed image through polarized lenses such as polarized glasses. Therefore, a polarizer with a phase retardation layer and an adhesive layer can also be appropriately applied to image display devices that can be used outdoors.

[0071] 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. It should be noted that, in the case of surface treatment, the thickness of the outer protective layer includes the thickness of the surface treatment layer.

[0072] In one embodiment, the second protective layer 13 is preferably optically isotropic. In this specification, "optically isotropic" means that the in-plane phase difference Re(550) is 0 nm to 10 nm and the phase difference Rth(550) in the thickness direction is -10 nm to +10 nm.

[0073] D. Phase difference layer

[0074] D-1. Characteristics of the phase difference layer

[0075] As described above, the in-plane phase difference Re(550) of the retardation layer is 100nm to 200nm, preferably 110nm to 180nm, more preferably 120nm to 160nm, and even more preferably 130nm to 150nm. That is, the retardation layer can function as a so-called λ / 4 waveplate.

[0076] As described above, the retardation layer satisfies the relationship Re(450) < Re(550), and preferably further satisfies the relationship Re(550) < Re(650). That is, the retardation layer exhibits a wavelength dependence of inverse dispersion, where the phase difference value increases with the wavelength of the measured light. The Re(450) / Re(550) of the retardation film is, for example, greater than 0.5 and less than 1.0, preferably 0.7 to 0.95, more preferably 0.75 to 0.92, and even more preferably 0.8 to 0.9. The Re(650) / Re(550) is preferably 1.0 or more and less than 1.15, more preferably 1.03 to 1.1.

[0077] As described above, the retardation layer has an in-plane phase difference, and therefore exhibits a relationship of nx > ny. As long as the retardation layer has a relationship of nx > ny, it can display any suitable refractive index characteristic. The refractive index characteristic of the retardation layer typically shows a relationship of nx > ny ≥ nz. It should be noted that "ny = nz" here includes not only the case where ny and nz are exactly equal, but also the case where they are substantially equal. Therefore, the case of ny < nz can be included without impairing the effect of the present invention. The Nz coefficient of the retardation layer is preferably 0.9 to 2.0, more preferably 0.9 to 1.5, and even more preferably 0.9 to 1.2. By satisfying this relationship, when a polarizer with a retardation layer and an adhesive layer is used in an image display device, very excellent reflective hue can be achieved.

[0078] The thickness of the retardation layer can be set in a manner that best enables it to function as a λ / 4 waveplate. In other words, the thickness can be set in a way that yields the desired in-plane phase difference. Specifically, the thickness is preferably 15 μm to 60 μm, more preferably 20 μm to 55 μm, and most preferably 20 μm to 50 μm.

[0079] The absolute value of the photoelastic coefficient of the phase retardation layer is preferably 20 × 10⁻⁶. -12 (m 2 / N) or less, more preferably 1.0×10 -12 (m 2 / N)~15×10 -12 (m 2 / N), further preferably 2.0×10 -12 (m 2 / N)~12×10 -12 (m 2 / N). If the absolute value of the photoelastic coefficient is within such a range, then when a polarizer with a phase retardation layer and an adhesive layer is applied to an image display device, display unevenness can be suppressed.

[0080] In a humidification TMA test where the environment is changed in the sequence of 25°C / 50%RH, 60°C / 50%RH, and 60°C / 85%RH, the dimensional change rate of the phase retardation layer in the slow axis direction is preferably 0.45% or less, more preferably 0.35% or less, even more preferably 0.28% or less, and particularly preferably 0.22% or less. If the dimensional change rate of the phase retardation layer in the humidification TMA test is below such an upper limit, the peeling of the polarizer with the phase retardation layer and adhesive layer from the adhered material in a high humidity environment can be suppressed, thereby improving the high humidity durability of the polarizer with the phase retardation layer and adhesive layer. It should be noted that in the humidification TMA test where the environment is changed in the sequence of 25°C / 50%RH, 60°C / 50%RH, and 60°C / 85%RH, the dimensional change rate of the phase retardation layer in the slow axis direction is, for example, 0% or more. Furthermore, in the case where the polarizer with the phase retardation layer and the adhesive layer further has an additional phase retardation layer (not shown), the dimensional change rate of the phase retardation layer in the slow axis direction in the above-mentioned humidification TMA test is measured with the additional phase retardation layer attached to the phase retardation layer, and the range of the dimensional change rate is the same as that described above.

[0081] D-2. Materials constituting the retardation layer

[0082] The retardation layer typically contains a resin comprising at least one bonding group selected from carbonate bonds and ester bonds. In other words, the retardation layer contains a polycarbonate resin, a polyester resin, or a polyester-carbonate resin (hereinafter, they are sometimes collectively referred to as polycarbonate resins, etc.). The polycarbonate resin, etc., comprises at least one structural unit selected from the structural units represented by the above general formula (1) and / or the structural units represented by the above general formula (2). These structural units are derived from divalent oligofluorene structural units, hereinafter, sometimes referred to as oligofluorene structural units. Such polycarbonate resins, etc., have positive refractive index anisotropy.

[0083] In one embodiment, the phase retardation layer may further contain an acrylic resin. The content of the acrylic resin is 0.5% to 1.5% by mass. It should be noted that, in this specification, the percentage or part in the unit "mass" has the same meaning as the percentage or part in the unit "weight".

[0084] D-2-1. Polycarbonate resins, etc.

[0085] <Oligoflurane structural unit>

[0086] The oligomeric fluorene structural unit is represented by the above general formula (1) or (2). In general formulas (1) and (2), R 1 ~R 3 Each is independently a directly bonded, substituted, or unsubstituted alkylene group having 1 to 4 carbon atoms, R 4 ~R9 Each of the following groups is independently a hydrogen atom, an alkyl group with 1 to 10 substituted or unsubstituted carbon atoms, an aryl group with 4 to 10 substituted or unsubstituted carbon atoms, an acyl group with 1 to 10 substituted or unsubstituted carbon atoms, an alkoxy group with 1 to 10 substituted or unsubstituted carbon atoms, an aryloxy group with 1 to 10 substituted or unsubstituted carbon atoms, an amino group with 1 to 10 substituted or unsubstituted carbon atoms, an ethynyl group with 1 to 10 substituted or unsubstituted carbon atoms, a sulfur atom with a substituent, a silicon atom with a substituent, a halogen atom, a nitro group, or a cyano group. Wherein, R 4 ~R 9 R can be either the same or different from each other. 4 ~R 9 At least two adjacent groups can also bond with each other to form a ring.

[0087] The content of oligofluorene structural units in polycarbonate resins and the like is preferably 1% to 40% by mass, more preferably 10% to 35% by mass, further preferably 15% to 30% by mass, and particularly preferably 18% to 25% by mass relative to the total resin content. Excessive content of oligofluorene structural units can lead to problems such as an excessively large photoelasticity coefficient, insufficient reliability, and insufficient phase difference performance. Furthermore, a higher proportion of oligofluorene structural units in the resin can sometimes narrow the range of molecular design, making it difficult to improve the resin when 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, the optical properties will change sensitively to even small deviations in the content of the oligofluorene structural units, making it sometimes difficult to manufacture in a way that ensures various properties fall within a certain range.

[0088] Details of the oligomeric fluorene structural unit are described, for example, in International Publication No. 2015 / 159928. This publication is incorporated herein by reference.

[0089] <Other Structural Units>

[0090] Typically, polycarbonate resins and the like may contain other structural units besides the oligofluorene structural unit. In one embodiment, the other structural units are preferably derived from dihydroxy compounds or diester compounds. To exhibit the desired reverse dispersion wavelength properties, structural units with positive birefringence must be introduced into the polymer structure along with oligofluorene structural units with negative birefringence. Therefore, dihydroxy compounds or diester compounds that are the raw materials for structural units with positive birefringence are further preferred as other monomers for copolymerization.

[0091] Examples of comonomers include compounds that can introduce structural units containing aromatic rings, and compounds that do not introduce structural units containing aromatic rings, i.e., compounds composed of aliphatic structures.

[0092] The following are specific examples of compounds composed of aliphatic structures: dihydroxy compounds of straight-chain aliphatic hydrocarbons such as ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 1,5-heptanediol, 1,6-hexanediol, 1,9-nonanediol, 1,10-decanediol, and 1,12-dodecanediol; dihydroxy compounds of branched aliphatic hydrocarbons such as neopentyl glycol and hexanediol; and secondary and tertiary alcohols of alicyclic hydrocarbons, such as 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,3-adamantanediol, hydrogenated bisphenol A, and 2,2,4,4-tetramethyl-1,3-cyclobutanediol. Dihydroxy compounds; dihydroxy compounds that are primary alcohols of alicyclic hydrocarbons, such as 1,2-cyclohexanediethanol, 1,3-cyclohexanediethanol, 1,4-cyclohexanediethanol, tricyclodecanediethanol, pentacyclopentadecanedimethanol, 2,6-naphthylanediethanol, 1,5-naphthylanediethanol, 2,3-naphthylanediethanol, 2,3-norbornanediethanol, 2,5-norbornanediethanol, 1,3-adamantanediethanol, and dihydroxy compounds derived from terpenes such as limonene; alkylene glycols such as diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, and polypropylene glycol; dihydroxy compounds with cyclic ether structures such as isosorbide; spirodiol, di... Dihydroxy compounds with cyclic acetal structures, such as alkyldiols; alicyclic dicarboxylic acids such as 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid; and aliphatic dicarboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, octanoic acid, azelaic acid, and sebacic acid.

[0093] The following are specific examples of compounds that can incorporate structural units containing aromatic rings: 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-diphenyl)phenyl)propane, 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane, bis(4- 1,1-Bis(4-hydroxyphenyl)methane, 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(4-hydroxyphenyl)-2-propyl ... Aromatic bisphenol compounds such as (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, 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; 2,2-bis(4-(2-hydroxyethoxy)phenyl)propane, 2,2-bis... Dihydroxy compounds containing an ether group bonded to an aromatic group, such as (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'-diphenyl ether dicarboxylic acid, 4,4'-benzophenone dicarboxylic acid, 4,4'-diphenoxyethane dicarboxylic acid, 4,4'-diphenyl sulfone dicarboxylic acid, and 2,6-naphthalene dicarboxylic acid.

[0094] It should be noted that the aliphatic and aromatic dicarboxylic acids mentioned above can be used as raw materials for the aforementioned polyester carbonates in the form of dicarboxylic acids themselves, or dicarboxylic acid derivatives such as methyl esters, phenyl esters, and dicarboxylic acid halides can be used as raw materials depending on the manufacturing method.

[0095] As comonomers, dihydroxy compounds with fluorene rings, such as 9,9-bis(4-(2-hydroxyethoxy)phenyl)fluorene, 9,9-bis(4-hydroxyphenyl)fluorene, and 9,9-bis(4-hydroxy-3-methylphenyl)fluorene, which are known in the past as compounds containing structural units with negative birefringence, as well as dicarboxylic acid compounds with fluorene rings, can also be used in combination with oligomeric fluorene compounds.

[0096] In the structural unit that can be introduced by the above-mentioned compound having an alicyclic structure, the resin used in the present invention preferably contains the structural unit represented by the following formula (3) as a copolymer component.

[0097] [Chemical Formula 3]

[0098]

[0099] Spirodiol can be used as a dihydroxy compound that can incorporate the structural unit of the above formula (3).

[0100] In the resin used in this invention, it is preferable to contain 5% by mass or more and 90% by mass or less of the structural unit represented by formula (3) above. The upper limit is further preferably 70% by mass or less, and particularly preferably 50% by mass or less. The lower limit is further preferably 10% by mass or more, more preferably 20% by mass or more, and particularly preferably 25% by mass or more. When the content of the structural unit represented by formula (3) above the above lower limit is above, sufficient mechanical properties, heat resistance, and low photoelasticity can be obtained. In addition, the compatibility with acrylic resins is improved, and the transparency of the obtained resin composition can be further improved. Furthermore, the polymerization reaction of spirodiol is relatively slow, so by suppressing the content to below the above upper limit, the polymerization reaction can be easily controlled.

[0101] The resin used in this invention preferably further contains structural units represented by the following formula (4) as copolymer components.

[0102] [Chemical Formula 4]

[0103]

[0104] Examples of dihydroxy compounds that can incorporate the structural unit represented by formula (4) above include isosorbide (ISB), isomannitol, and isoidet, which are stereoisomers. These dihydroxy compounds can be used alone or in combination of two or more.

[0105] The resin used in this invention preferably contains 5% by mass or more and 90% by mass or less of the structural unit represented by formula (4) above. The upper limit is further preferably 70% by mass or less, and particularly preferably 50% by mass or less. The lower limit is further preferably 10% by mass or more, and particularly preferably 15% by mass or more. When the content of the structural unit represented by formula (4) above is above the lower limit, sufficient mechanical properties, heat resistance, and low photoelasticity can be obtained. In addition, the structural unit represented by formula (4) above has the characteristic of high water absorption. Therefore, if the content of the structural unit represented by formula (4) above is below the upper limit, the dimensional changes of the molded article caused by water absorption can be suppressed to an acceptable range.

[0106] The resin used in this invention may further contain additional structural units. It should be noted that these structural units are sometimes referred to as "other structural units." 1,4-cyclohexanediethanol, tricyclodecanediethanol, and 1,4-cyclohexanedicarboxylic acid (and their derivatives) are more preferably monomers containing other structural units; 1,4-cyclohexanediethanol and tricyclodecanediethanol are particularly preferred. Resins containing structural units from these monomers exhibit an excellent balance of optical properties, heat resistance, and mechanical properties. Furthermore, diester compounds have relatively low polymerization reactivity; therefore, from the viewpoint of improving reaction efficiency, it is preferable not to use diester compounds other than those containing oligomeric fluorene structural units.

[0107] The glass transition temperature (Tg) of the resin used in this invention is preferably 110°C or higher and 160°C or lower. The upper limit is further preferably 155°C or lower, more preferably 150°C or lower, and particularly preferably 145°C or lower. The lower limit is further preferably 120°C or higher, and particularly preferably 130°C or higher. When the glass transition temperature is outside the above range, there is a tendency for heat resistance to deteriorate, and there is a possibility of dimensional changes after film formation, or a decrease in the reliability of the phase difference film under operating conditions. On the other hand, if the glass transition temperature is too high, there is a possibility of uneven film thickness during film formation, or the film becoming brittle and having poor tensile strength. Furthermore, there is a possibility of damage to the transparency of the film.

[0108] Detailed information regarding the composition and manufacturing methods of polycarbonate resins, etc., is described, for example, in International Publication No. 2015 / 159928 (as described above). This description is incorporated herein by reference.

[0109] D-2-2. Acrylic resins

[0110] As acrylic resins, acrylic resins that are thermoplastic resins can be used. Examples of monomers that form the structural units of acrylic resins include: methyl methacrylate, methacrylic acid, methyl acrylate, acrylic acid, benzyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, tridecyl methacrylate, stearyl methacrylate, glycidyl methacrylate, hydroxypropyl methacrylate, 2-methoxyethyl methacrylate, 2-ethoxyethyl methacrylate, cyclohexyl methacrylate, isoborneol methacrylate, norborneol methacrylate, dicyclopentenyl methacrylate, dicyclopentyl methacrylate, etc. Dicyclopentenoxyethyl acrylate, tetrahydrofurfuryl acrylate, acryloyl(meth)acrylate, 2-hydroxyethyl acrylate, 2-(meth)acryloyloxyethyl succinate, 2-(meth)acryloyloxyethyl maleate, 2-(meth)acryloyloxyethyl phthalate, 2-(meth)acryloyloxyethyl hexahydrophthalate, pentamethylpiperidinyl acrylate, tetramethylpiperidinyl acrylate, dimethylaminoethyl acrylate, diethylaminoethyl acrylate, cyclopentyl methacrylate, cyclopentyl acrylate, cyclohexyl methacrylate, cyclohexyl acrylate, cycloheptyl methacrylate, cycloheptyl acrylate, cyclooctyl methacrylate, cyclooctyl acrylate, cyclododecyl methacrylate, cyclododecyl acrylate. These compounds can be used alone or in combination of two or more monomers. Examples of using two or more monomers in combination include copolymers of two or more monomers, blends of two or more monomers in a homopolymer of one monomer, and combinations thereof. In addition, other monomers that can copolymerize with these acrylic monomers (e.g., olefin monomers, vinyl monomers) can also be used in combination.

[0111] The acrylic resin contains structural units derived from methyl methacrylate. The content of the methyl methacrylate structural units in the acrylic resin is preferably 70% by mass or more and 100% by mass or less. More preferably, it is 80% by mass or more, further preferably 90% by mass or more, and particularly preferably 95% by mass or more. Within this range, excellent compatibility with the polycarbonate resin of the present invention can be obtained. As structural units other than methyl methacrylate, methyl acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, and styrene are preferably used. Copolymerizing methyl acrylate improves thermal stability. By using phenyl (meth)acrylate, benzyl (meth)acrylate, and styrene, the refractive index of the acrylic resin can be adjusted; therefore, by matching the refractive index with that of the combined resin, the transparency of the resulting resin composition can be improved. By using such an acrylic resin, a reverse dispersion phase difference film with excellent elongation and phase difference performance and low haze can be obtained.

[0112] The weight-average molecular weight (Mw) of the acrylic resin is 10,000 or more and 200,000 or less. The lower limit is preferably 30,000 or more, particularly preferably 50,000 or more. The upper limit is preferably 180,000 or less, particularly preferably 150,000 or less. When the molecular weight is within this range, compatibility with polycarbonate resins can be obtained, thereby improving the transparency of the final retardation film (retardation layer) and sufficiently improving elongation during stretching. It should be noted that the above-mentioned weight-average molecular weight is the molecular weight converted from polystyrene measured by GPC. Furthermore, from a compatibility point of view, the acrylic resin preferably does not contain substantially branched structures. The absence of branched structures can be confirmed by the unimodality of the GPC curve of the acrylic resin, etc.

[0113] D-2-3. Blending of polycarbonate resins with acrylic resins

[0114] A method for manufacturing a phase retardation film (phase retardation layer) by blending polycarbonate resins and acrylic resins into a resin composition (the manufacturing method is described in section C-3 below). It is preferable that the polycarbonate resins and acrylic resins are blended in the molten state. A representative example of a method for blending in the 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. When the mixing temperature is within this range, granules of a resin composition uniformly blended from the two resins can be obtained while suppressing thermal decomposition. When the molten resin temperature in the extruder exceeds 280°C, resin coloring and / or thermal decomposition may sometimes occur. On the other hand, when the molten resin temperature in the extruder is below 200°C, the resin viscosity may sometimes become too high, placing an excessive load on the extruder, or the resin melting may become insufficient. It should be noted that any suitable configuration can be used for the extruder, screw, etc. To obtain the transparency of the resin suitable for optical film applications, a twin-screw extruder is preferred. Furthermore, residual low-molecular-weight components in the resin and low-molecular-weight thermally decomposed components from extrusion compounding pose a risk of contaminating the cooling and conveying rollers during the film-forming and stretching processes. Therefore, to remove these components, an extruder equipped with a vacuum exhaust port is preferred.

[0115] The content of acrylic resin in the resin composition (which results in a phase retardation layer) is, for example, 0.5% by mass or more and 2.0% by mass or less. The lower limit is more preferably 0.6% by mass or more. The upper limit is preferably 1.5% by mass or less, more preferably 1.0% by mass or less, further preferably 0.9% by mass or less, and particularly preferably 0.8% by mass or less. In this way, by incorporating acrylic resin into polycarbonate resin in a very specific ratio, elongation and phase retardation performance can be significantly increased. Furthermore, haze can be suppressed. Such an effect is not theoretically clear, but is an unexpectedly excellent effect obtained through repeatability tests. It should be noted that when the content of acrylic resin is too low, the above-mentioned effect is sometimes not obtained. On the other hand, when the content of acrylic resin is too high, haze may sometimes increase. In addition, elongation and phase retardation performance are often insufficient or even reduced compared to the cases within the above ranges.

[0116] For the purpose of modifying properties such as mechanical properties and / or solvent resistance, the resin composition may be further blended with synthetic resins such as aromatic polycarbonate, aliphatic polycarbonate, aromatic polyester, aliphatic polyester, polyamide, polystyrene, polyolefin, acrylic acid, amorphous polyolefin, ABS, AS, polylactic acid, polybutylene succinate, rubber, and combinations thereof.

[0117] The resin composition may further include additives. Specific examples of additives include: heat stabilizers, antioxidants, catalyst deactivators, ultraviolet absorbers, light stabilizers, release agents, dyes and pigments, impact modifiers, antistatic agents, slip agents, lubricants, plasticizers, compatibilizers, nucleating agents, flame retardants, inorganic fillers, and foaming agents. The type, quantity, combination, and content of additives contained in the resin composition can be appropriately set according to the purpose.

[0118] D-3. Methods for forming phase difference layers

[0119] The retardation layer is obtained by forming a film from the resin composition described in section D-2 above, and then stretching the film. Any suitable molding process can be used as a method for forming the film from the resin composition. Specific examples include compression molding, transfer molding, injection molding, extrusion molding, blow molding, powder molding, FRP molding, casting coating (e.g., casting), calendering, and hot pressing. Among these, extrusion molding or casting coating, which improves the smoothness of the obtained film and provides good optical uniformity, is preferred. Casting coating has the potential to cause problems due to residual solvents; therefore, extrusion molding is particularly preferred, especially melt extrusion molding using a T-die, which is preferred from the viewpoint of film productivity and ease of subsequent stretching. The molding conditions can be appropriately set according to the composition and type of the resin used, the desired characteristics of the retardation layer, etc. In this way, a resin film containing polycarbonate resins and acrylic resins can be obtained.

[0120] The thickness of the resin film (unstretched film) can be set to any appropriate value based on the desired thickness of the resulting retardation layer, the desired optical properties, the stretching conditions described later, etc. Preferably, it is 50 μm to 300 μm.

[0121] The aforementioned stretching can be performed using any appropriate stretching method and conditions (e.g., stretching temperature, stretching ratio, stretching direction). Specifically, various stretching methods such as free-end stretching, fixed-end stretching, free-end contraction, and fixed-end contraction can be used individually, simultaneously, or gradually. The stretching direction can also be performed in various directions and dimensions, such as length, width, thickness, and inclination.

[0122] By appropriately selecting the stretching method and stretching conditions described above, a phase difference layer with the desired optical properties (e.g., refractive index characteristics, in-plane phase difference, Nz coefficient) can be obtained.

[0123] In one embodiment, the stretching temperature of the film is below the glass transition temperature (Tg) of the polycarbonate resin or the like. Typically, when stretching a polycarbonate resin or the like, the film is in a glassy state at temperatures below Tg, and therefore, stretching is practically impossible. The resin film used in the embodiments of the present invention, by incorporating a small amount of acrylic resin (typically polymethyl methacrylate), can achieve stretching below Tg without substantially changing the Tg of the polycarbonate resin or the like. Furthermore, although not theoretically clear, by stretching below Tg, a reverse dispersion phase difference film (phase difference layer) with excellent elongation and phase difference performance and low haze can be achieved. Specifically, the stretching temperature is preferably Tg to Tg-10°C, more preferably Tg to Tg-8°C, and even more preferably Tg to Tg-5°C. It should be noted that if the film is at, for example, around Tg+5°C or below, or for example around Tg+2°C, stretching can be appropriately performed even at temperatures above Tg.

[0124] In this way, a phase retardation film constituting the phase retardation layer can be obtained.

[0125] Alternatively, commercially available stretch films can be used as phase retardation films. These films can be used directly or after secondary processing (e.g., stretching or surface treatment) depending on the intended purpose. A specific example of a commercially available film is "PURE-ACE RM" manufactured by Teijin Corporation.

[0126] E. First adhesive layer and second adhesive layer

[0127] E-1. Characteristics of the first adhesive layer and / or the second adhesive layer

[0128] As described above, the paste offset of the first adhesive layer 20 after a heating test at 85°C for 500 hours is 900 μm or less, preferably 600 μm or less, more preferably 500 μm or less, further preferably 400 μm or less, particularly preferably 300 μm or less, especially preferably 250 μm or less, and most preferably 180 μm or less. The lower limit of the paste offset can be, for example, 20 μm. By using an adhesive with such a range of paste offset (preferably small paste offset) for bonding the polarizer and the retardation layer, a polarizer with a retardation layer and adhesive layer that suppresses phase difference unevenness in a high-temperature environment can be achieved by utilizing the synergistic effect with the effect of controlling the creep value of the second adhesive layer, as described later. It should be noted that, in this specification, "paste offset" refers to the length of the portion of the adhesive layer that overflows most from the end faces of the polarizer and retardation layer after a heating test, for a polarizer with a retardation layer and adhesive layer.

[0129] As described above, the creep value of the second adhesive layer 40 at 85°C is 40 μm or less, preferably 30 μm or less, more preferably 25 μm or less, further preferably 20 μm or less, and particularly preferably 15 μm or less. The lower limit of the creep value can be, for example, 5 μm. By using an adhesive with a low creep value for bonding a polarizer with a phase retardation layer and an adhesive layer to an image display unit, an image display device that suppresses color unevenness in high-temperature environments can be achieved by utilizing the synergistic effect with the effect of controlling the paste offset of the first adhesive layer described above. The creep value can be determined, for example, by pasting a test sample cut from the adhesive sheet onto a support plate with a 10 mm × 10 mm joint surface. At 85°C, a load of 500 gf is applied vertically downwards while the support plate with the test sample attached is fixed. The offset from the support plate is measured after 1 second and 3600 seconds of the applied load, and these offsets are denoted as Cr1 and Cr, respectively. 3600 . Will be composed of Cr1 and Cr 3600 The creep value is calculated using the following formula. It should be noted that the creep value in this specification is based on a 20μm thickness of the adhesive layer.

[0130] ΔCr=Cr 3600 -Cr1

[0131] The storage modulus of the first adhesive layer and / or the second adhesive layer at 85°C is preferably 1.0 × 10⁻⁶. 4 Pa or higher, preferably 2.0 × 10 Pa 4 Pa or higher, more preferably 5.0 × 10 Pa 4 Pa or higher, more preferably 1.0 × 10 Pa 5 Pa or higher. When the storage modulus is in this range, it is easy to achieve the aforementioned desired paste offset and / or creep value. On the other hand, the storage modulus is, for example, 3.0 × 10⁻⁶ Pa. 6 Below Pa.

[0132] The thickness of the first adhesive layer is preferably 2 μm to 50 μm, more preferably 3 μm to 40 μm. The thickness of the second adhesive layer is preferably 4 μm to 30 μm, more preferably 5 μm to 20 μm. With the thicknesses of the first and second adhesive layers within this range, a polarizer with a phase retardation layer and an adhesive layer can be realized, utilizing the synergistic effect with the aforementioned effects of controlling paste offset and creep value, thereby suppressing phase differences in high-temperature environments. Furthermore, an image display device that suppresses color unevenness in high-temperature environments can be realized.

[0133] E-2. Materials constituting the first adhesive layer and the second adhesive layer

[0134] For the first and second adhesive layers, any suitable configuration can be used as long as the first adhesive layer has the desired paste offset and the second adhesive layer has the desired creep value. The first and second adhesive layers can be formed from the same adhesive or from different adhesives. Hereinafter, the first and second adhesive layers will be described as a single adhesive layer. The paste offset and / or creep value can be controlled by adjusting the composition of the adhesives constituting the adhesive layers (e.g., the type of base polymer (polarity, Tg, softness), molecular weight), crosslinking structure (e.g., the type of crosslinking agent, the distance between crosslinking points (molecular weight between crosslinking points), crosslinking density), etc.

[0135] E-2-1. Basic Polymer

[0136] Typically, the adhesive layer is 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 using a (meth)acrylic polymer as the base polymer, the adhesive layer is, for example, formed from an adhesive composition containing a (meth)acrylic polymer (A). The (meth)acrylic polymer (A) contains an alkyl (meth)acrylic ester as a main component.

[0137] <(Meth)acrylic polymers (A)>

[0138] As described above, the (meth)acrylic polymer (A) contains alkyl (meth)acrylate as a main component. From the viewpoint of improving the adhesion of the adhesive layer, alkyl (meth)acrylate is preferably 50% by weight or more of the total monomer components forming the (meth)acrylic polymer (A), while the remaining monomers other than the alkyl (meth)acrylate can be arbitrarily set. It should be noted that (meth)acrylate refers to acrylates and / or methacrylates.

[0139] Alkyl methacrylates, which form the main backbone of the (meth)acrylic polymer (A), can be exemplified by linear or branched alkyl groups having 1 to 18 carbon atoms. Examples of alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, hexyl, cyclohexyl, heptyl, 2-ethylhexyl, isooctyl, nonyl, decyl, isodecyl, dodecyl, isotetradecyl, undecyl, tridecyl, pentadecyl, hexadecyl, heptadecanyl, octadecyl, etc. Alkyl methacrylates can be used alone or in combination. The average number of carbon atoms in the alkyl group is preferably 3 to 10.

[0140] As a monomer component of (meth)acrylic polymer (A), in addition to alkyl (meth)acrylates, it may also contain comonomers such as carboxyl-containing monomers (a1) and hydroxyl-containing monomers (a2). Comonomers can be used alone or in combination.

[0141] Carboxyl-containing monomers (a1) are compounds whose structures contain a carbonyl group and polymerizable unsaturated double bonds such as (meth)acryloyl groups and vinyl groups. Examples of carboxyl-containing monomers include (meth)acrylic acid, carboxyethyl (meth)acrylic acid, carboxypentyl (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, and crotonic acid. Among these, acrylic acid is preferred from the viewpoints of copolymerization, price, and improving the adhesive properties of the adhesive layer. In the adhesive composition constituting the first adhesive layer and / or the adhesive composition constituting the second adhesive layer, the (meth)acrylic polymer (A) (the base polymer) preferably contains carboxyl-containing monomers, and more preferably acrylic acid.

[0142] When using a carboxyl-containing monomer (a1) as a monomer component, the content of the carboxyl-containing monomer (a1) in all monomer components forming the (meth)acrylic polymer (A) is typically 0.01% by weight or more and 10% by weight or less.

[0143] Hydroxyl-containing monomers (a2) are compounds whose structures contain hydroxyl groups and polymerizable unsaturated double bonds such as (meth)acryloyl groups and vinyl groups. Examples of hydroxyl-containing monomers include: 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylaurate (meth)acrylate, and other hydroxyalkyl (meth)acrylates; methyl (4-hydroxymethylcyclohexyl)acrylate, etc. From the viewpoint of improving the durability of the adhesive layer, 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are preferred, and 4-hydroxybutyl (meth)acrylate is more preferred.

[0144] When using a hydroxyl-containing monomer (a2) as a monomer component, the content of the hydroxyl-containing monomer (a2) in all monomer components forming the (meth)acrylic polymer (A) is typically 0.01% by weight or more and 10% by weight or less.

[0145] The (meth)acrylic polymer (A) preferably contains monomers with a glass transition temperature of 0°C or higher and having unsaturated carbon double bonds as monomer components. Examples of monomers (a3) ​​with a glass transition temperature of 0°C or higher and having unsaturated carbon double bonds as homopolymers include alkyl methacrylate monomers and (meth)acrylic acid. Monomer (a3) ​​is preferably a monomer with a glass transition temperature of 20°C or higher and having unsaturated carbon double bonds as homopolymers, and more preferably a monomer with a glass transition temperature of 40°C or higher and having unsaturated carbon double bonds as homopolymers.

[0146] In (meth)acrylic polymers (A), the proportion of monomer (a3) ​​is not particularly limited. The content is typically 0.1% to 40% by weight, more preferably 1% to 30% by weight. It should be noted that when two or more monomers (a3) ​​are used in combination, the content is the total content.

[0147] Examples of monomers (a3) ​​include: methyl acrylate (Tg: 8℃), methyl methacrylate (Tg: 105℃), ethyl methacrylate (Tg: 65℃), n-propyl acrylate (Tg: 3℃), n-propyl methacrylate (Tg: 35℃), n-pentyl acrylate (Tg: 22℃), n-tetradecyl acrylate (Tg: 24℃), n-hexadecyl acrylate (Tg: 35℃), n-hexadecyl methacrylate (Tg: 15℃), n-stearyl acrylate (Tg: 30℃), and n-stearyl methacrylate (Tg: 15℃). Straight-chain alkyl esters of (meth)acrylate, such as tert-butyl acrylate (Tg: 43℃), tert-butyl methacrylate (Tg: 48℃), isopropyl methacrylate (Tg: 81℃), and isobutyl methacrylate (Tg: 48℃); branched-chain alkyl esters of (meth)acrylate, such as cyclohexyl acrylate (Tg: 19℃), cyclohexyl methacrylate (Tg: 65℃), isobornyl acrylate (Tg: 94℃), and isobornyl methacrylate (Tg: 180℃); acrylic acid (Tg: 106℃), etc. These can be used alone or in combination.

[0148] For comonomers, when the adhesive composition contains a crosslinking agent (described later), carboxyl-containing monomers and hydroxyl-containing monomers become reaction sites with the crosslinking agent. Since carboxyl-containing monomers and hydroxyl-containing monomers have high reactivity with intermolecular crosslinking agents, they are preferred for use in order to improve the cohesiveness and heat resistance of the resulting adhesive layer. Furthermore, carboxyl-containing monomers are preferred in terms of both durability and reworkability, while hydroxyl-containing monomers are preferred in terms of improving reworkability.

[0149] As a monomer component, other comonomers (a4) can be further used. These other comonomers (a4) have polymerizable functional groups with unsaturated double bonds, such as (meth)acryloyl or vinyl groups. By using other comonomers (a4), the adhesion and heat resistance of the adhesive layer can be improved. These other comonomers (a4) can be used alone or in combination.

[0150] By using amino-containing monomers and amide-containing monomers as other comonomers (a4), the adhesion of the adhesive layer can be improved. Examples of amino-containing monomers include N,N-dimethylaminoethyl methacrylate and N,N-dimethylaminopropyl methacrylate. Examples of monomers containing amide groups include: (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-isopropylacrylamide, N-methyl(meth)acrylamide, N-butyl(meth)acrylamide, N-hexyl(meth)acrylamide, N-hydroxymethyl(meth)acrylamide, N-hydroxymethyl-N-propane(meth)acrylamide, aminomethyl(meth)acrylamide, aminoethyl(meth)acrylamide, mercaptomethyl(meth)acrylamide, mercaptoethyl(meth)acrylamide, and other acrylamide monomers; N-(meth)acryloylmorpholine, N-(meth)acryloylpiperidine, N-(meth)acryloylpyrrolidine, and other N-acryloyl heterocyclic monomers; and N-vinylpyrrolidone, N-vinyl-ε-caprolactam, and other monomers containing N-vinyl lactams.

[0151] Other comonomers (a4) can be multifunctional monomers. By using multifunctional monomers, it is possible to adjust the gel fraction of the adhesive layer and control the cohesiveness. Examples of multifunctional monomers include: hexanediol di(meth)acrylate (1,6-hexanediol di(meth)acrylate), butanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, allyl methacrylate, vinyl methacrylate, epoxy acrylate, polyester acrylate, urethane acrylate, and other multifunctional acrylates; and divinylbenzene. The preferred polyfunctional acrylates are 1,6-hexanediol diacrylate and dipentaerythritol hexa(meth)acrylate.

[0152] Other comonomers (a4) besides those mentioned above may include, for example: 2-methoxyethyl methacrylate, 2-ethoxyethyl methacrylate, methoxytriethylene glycol methacrylate, 3-methoxypropyl methacrylate, 3-ethoxypropyl methacrylate, 4-methoxybutyl methacrylate, 4-ethoxybutyl methacrylate, and other alkoxyalkyl esters of methacrylate; cyclizable monomers such as methyl 2-(allyloxymeth)acrylate; and epoxy-containing monomers such as glycidyl methacrylate and methyl glycidyl methacrylate. The adhesive composition comprising: sulfonic acid monomers such as sodium vinyl sulfonate; phosphate monomers; (meth)acrylates having alicyclic hydrocarbon groups such as cyclopentyl methacrylate, cyclohexyl methacrylate, and isobornyl methacrylate; (meth)acrylates having aromatic hydrocarbon groups such as phenyl methacrylate, phenoxyethyl methacrylate, and benzyl methacrylate; vinyl esters such as vinyl acetate and vinyl propionate; aromatic vinyl compounds such as styrene and vinyltoluene; olefins or dienes such as ethylene, propylene, butadiene, isoprene, and isobutylene; vinyl ethers such as vinyl alkyl ethers; and vinyl chloride. In the adhesive composition constituting the first adhesive layer and / or the adhesive composition constituting the second adhesive layer, as a monomer component of the (meth)acrylate polymer (A) (the base polymer), it is preferable to include (meth)acrylates having aromatic hydrocarbon groups, and more preferably, benzyl methacrylate.

[0153] The content of other comonomers (a4) in the (meth)acrylic acid polymer is preferably 20% by mass or less, more preferably 10% by mass or less, further preferably 8% by mass or less, and particularly preferably 5% by mass or less.

[0154] The weight-average molecular weight (Mw) of the (meth)acrylic polymer (A) is, for example, 200,000 to 3,000,000, preferably 1,000,000 to 2,500,000, and more preferably 1,200,000 to 2,500,000. When the weight-average molecular weight (Mw) is within this range, an adhesive layer with excellent durability (especially heat resistance) can be obtained. When the weight-average molecular weight (Mw) exceeds 3,000,000, it can sometimes lead to an increase in viscosity and / or gelation during polymer polymerization.

[0155] E-2-2. Silane coupling agents containing reactive functional groups

[0156] The adhesive composition may comprise a silane coupling agent containing reactive functional groups. The reactive functional groups of the silane coupling agent are typically functional groups other than acid anhydride groups. Examples of functional groups other than acid anhydride groups include: epoxy, mercapto, amino, isocyanate, isocyanurate, vinyl, styryl, acetoacetyl, acylurea, thiourea, (meth)acrylate, heterocyclic groups, and combinations thereof. Silane coupling agents containing reactive functional groups can be used alone or in combination.

[0157] When a silane coupling agent containing reactive functional groups is incorporated into an adhesive composition, the amount of the silane coupling agent containing reactive functional groups is typically 0.001 parts by weight or more and 5 parts by weight or less relative to 100 parts by weight of the (meth)acrylic polymer (A).

[0158] E-2-3. Crosslinking agent

[0159] The adhesive composition may contain a crosslinking agent. Organic crosslinking agents, multifunctional metal chelates, etc., can be used as crosslinking agents. Examples of organic crosslinking agents include isocyanate crosslinking agents, peroxide crosslinking agents, epoxy crosslinking agents, and imine crosslinking agents. Multifunctional metal chelates are chelates formed by covalent or coordination bonds between multivalent metals and organic compounds. In the case of a radiation-curable adhesive composition, multifunctional monomers can be used as crosslinking agents. Crosslinking agents can be used alone or in combination.

[0160] When a crosslinking agent is incorporated into the adhesive composition, the amount of the crosslinking agent is typically 0.01 parts by weight or more and 15 parts by weight or less relative to 100 parts by weight of the (meth)acrylic polymer (A) (the base polymer). The adhesive composition constituting the second adhesive layer preferably contains 1.5 parts by weight or more, more preferably 2.0 parts by weight or more, further preferably 2.2 parts by weight or more, and particularly preferably 5 parts by weight or more of the crosslinking agent relative to 100 parts by weight of the (meth)acrylic polymer (A). When the amount of the crosslinking agent in the adhesive composition constituting the second adhesive layer is at or above this lower limit, the phase difference unevenness of the polarizer with the phase difference layer and the adhesive layer in a high-temperature environment can be stably suppressed by utilizing the synergistic effect with the effects of controlling the paste offset and creep value described above, and the color unevenness of the image display device in a high-temperature environment can also be stably suppressed.

[0161] When an isocyanate crosslinking agent is incorporated into an adhesive composition, the amount of the isocyanate crosslinking agent is typically 0.01 parts by weight or more and 15 parts by weight or less relative to 100 parts by weight of the (meth)acrylic polymer.

[0162] When peroxides are incorporated into the adhesive composition, the amount of peroxide is typically 0.01 parts by weight to 2 parts by weight or more relative to 100 parts by weight of the (meth)acrylic polymer. Within this range, processability and crosslinking stability can be easily adjusted.

[0163] E-2-4. Additives

[0164] The adhesive composition may contain (meth)acrylic oligomers and / or ionic compounds. Additionally, the adhesive composition may contain additives. Specific examples of additives include colorants, pigments and other powders, dyes, surfactants, plasticizers, tackifiers, surface lubricants, leveling agents, softeners, antioxidants, anti-aging agents, light stabilizers, UV absorbers, polymerization inhibitors, inorganic or organic fillers, metal powders, granules, and foils. Furthermore, a redox system with added reducing agents may be used within a controllable range. In one embodiment, the adhesive composition constituting the first adhesive layer may also contain a polyether compound having reactive groups (e.g., reactive silyl groups). The type, quantity, combination, and content of additives may be appropriately set according to the purpose. The content of additives is preferably 5 parts by weight or less, more preferably 3 parts by weight or less, and even more preferably 1 part by weight or less, relative to 100 parts by weight of the (meth)acrylic polymer (A).

[0165] F. Image display device

[0166] The polarizer with a phase retardation layer and an adhesive layer described in items A to E above can be applied to image display devices. Therefore, embodiments of the present invention also include image display devices using such polarizers with phase retardation layers and adhesive layers. Representative examples of image display devices include liquid crystal display devices and organic EL display devices. The image display device of the embodiments of the present invention typically includes, on its viewable side, a polarizer with a phase retardation layer and an adhesive layer described in items A to E above. The image display device includes an image display panel. The image display panel includes image display units. It should be noted that sometimes an image display device is referred to as an optical display device, sometimes an image display panel is referred to as an optical display panel, and sometimes an image display unit is referred to as an optical display unit.

[0167] Example

[0168] The present invention will now be described in detail with reference to specific embodiments, but the present invention is not limited to these embodiments. It should be noted that the methods for measuring each characteristic are as follows.

[0169] (1) Paste offset

[0170] A 13-inch polarizer with a phase retardation layer and an adhesive layer, obtained in the examples and comparative examples, was cut as a test sample. This test sample was subjected to a heating test at 85°C for 500 hours. After the heating test, the amount of the first adhesive layer overflowing from the end faces of the polarizer and phase retardation layer was observed and measured using an objective lens (20x). The length of the portion of the first adhesive layer with the largest overflow was taken as the paste offset. During observation, adjustments were made to ensure that the transmitted light was 0 (zero), and observation was performed using reflected light.

[0171] (2) Creep value

[0172] A 10mm × 30mm polarizer with a phase retardation layer and an adhesive layer, obtained in the examples and comparative examples, was cut as a test sample. The upper 10mm × 10mm portion of this test sample was attached to an SUS plate via a second adhesive layer, and a 500gf load was applied vertically downwards from the lower portion of the test sample. The offset between the test sample and the SUS plate was measured at 85°C after 1 second and 3600 seconds of the applied load, and these offsets were designated as Cr1 and Cr, respectively. 3600 Based on Cr1 and Cr 3600 The creep value is obtained by using the following formula: ΔCr.

[0173] ΔCr=Cr 3600 -Cr1

[0174] (3) Uneven color

[0175] A 13-inch polarizer with a phase retardation layer and an adhesive layer, obtained in the examples and comparative examples, was cut and bonded to a glass plate via a second adhesive layer to obtain a test sample. The test sample was subjected to a heating test at 85°C for 500 hours. After the heating test, it was placed on a reflective sheet (manufactured by Toray Thin Film Processing Co., Ltd., DMS vapor-deposited film), and the reflected hue α at the center of the sample was measured using a spectrophotometer (manufactured by Konica Minolta Co., Ltd., product name "CM-2600d"). * C and b * C and the reflected hue a at the end of the sample. * E and b * E Measurements were performed. Δab, calculated using the following formula, was used as an indicator of color unevenness. The smaller Δab is, the better the color unevenness.

[0176] Δab={(a * E -a * C ) 2 +(b *E -b * C ) 2} 1 / 2

[0177] (4) Light leakage

[0178] Two polarizers with phase retardation and adhesive layers obtained in the examples and comparative examples were cut into dimensions of 300 mm x 185 mm. These were laminated to both sides of a 0.07 mm thick alkali-free glass plate using a laminator in an orthogonal Nicol configuration, serving as primary samples. Next, the primary samples were autoclaved at 50°C and 5 atm for 15 minutes (the autoclaved samples are referred to as the "initial secondary samples"). Then, the initial secondary samples were treated at 85°C for 500 hours (the heated samples are referred to as the "heated secondary samples"). Both the initial and heated secondary samples were placed under a 10,000 kHz backlight, and light leakage was visually observed and evaluated according to the following criteria.

[0179] A: No light leakage occurred.

[0180] B: Slight light leakage occurs, but it does not occur in the display area and does not pose a practical problem.

[0181] C: There is slight light leakage in the display area, but there are no practical problems.

[0182] D: Significant light leakage occurred in the display area, posing a practical problem.

[0183] (5) Durability

[0184] The polarizer with a phase retardation layer and an adhesive layer obtained in the examples and comparative examples was cut into dimensions of 300 mm in length and 220 mm in width, and a test sample was obtained by bonding an alkali-free glass plate with a second adhesive layer. The test sample was subjected to a durability test at 60°C and 95% relative humidity for 240 hours. The test sample after the durability test was visually inspected and evaluated according to the following criteria.

[0185] A: The adhesive layer showed no signs of foaming, peeling, or other changes in appearance.

[0186] B: Slight foaming occurs at the ends of the adhesive layer, but there are no practical problems.

[0187] C: Significant peeling occurred at the ends of the adhesive layer, posing a practical problem.

[0188] (6) Dimensional change rate due to humidification (humidification TMA test)

[0189] The second retardation film was bonded to the first retardation film obtained in the manufacturing example in a combination of the first and second retardation layers shown in Table 1, resulting in a laminate of retardation films. The resulting laminate was cut into 20 mm (slow axis direction of the first retardation film) × 5 mm (fast axis direction of the first retardation film) pieces to obtain the measurement sample. It should be noted that in Example 9, the second retardation film was not bonded to the first retardation film, but the first retardation film was cut to obtain the measurement sample. Using a thermomechanical analysis apparatus, the environment was changed in the order of 25°C / 50%RH, 60°C / 50%RH, and 60°C / 85%RH, and the rate of dimensional change in the length direction (slow axis direction of the first retardation film) of the measurement sample was measured at 60°C / 85%RH. The holding time at 25℃ / 50%RH was set to 30 minutes, at 50℃ / 60%RH to 60 minutes, and at 60℃ / 85%RH to 240 minutes. The heating rate between 25℃ / 50%RH and 60℃ / 50%RH was set to 0.4℃ / min. The results are shown in Table 1.

[0190] [Abbreviation for compound]

[0191] The abbreviations of the compounds used in the following manufacturing examples are as follows.

[0192] ·BPFM: bis[9-(2-phenoxycarbonylethyl)fluorene-9-yl]methane

[0193] The synthesis was performed using the method described in Japanese Patent Application Publication No. 2015-25111.

[0194] [Chemical Formula 5]

[0195]

[0196] • ISB: Isosorbide [manufactured by Roquette Frères]

[0197] ·SPG: Spirodiol [manufactured by Mitsubishi Gas Chemical Co., Ltd.]

[0198] ·DPC: diphenyl carbonate [manufactured by Mitsubishi Chemical Corporation]

[0199] [Manufacturing Example 1: Fabrication of the first retardation film constituting the first retardation layer]

[0200] Polymerization was carried out using a batch polymerization unit consisting of two vertical reactors equipped with stirring blades and reflux condensers controlled at 100°C. The feed consisted of 29.60 parts by mass (0.046 mol) of BPFM, 29.21 parts by mass (0.200 mol) of ISB, 42.28 parts by mass (0.139 mol) of SPG, 63.77 parts by mass (0.298 mol) of DPC, and 1.19 × 10⁻⁶ calcium acetate monohydrate as a catalyst. -2 Parts by weight (6.78 × 10) -5 (mol). After purging the reactor with nitrogen under reduced pressure, it was heated with a heat medium, and stirring was started when the internal temperature reached 100°C. Forty minutes after the start of heating, the internal temperature was raised to 220°C. While maintaining this temperature, the pressure was reduced, reaching 13.3 kPa 90 minutes after reaching 220°C. Phenol vapor, a byproduct of the polymerization reaction, was introduced into a 100°C reflux condenser, allowing a certain amount of monomer components contained in the phenol vapor to return to the reactor, while the uncondensed phenol vapor was recovered in a 45°C condenser. Nitrogen was introduced into the first reactor to temporarily restore the pressure to atmospheric pressure, and the oligomerized reaction liquid in the first reactor was transferred to the second reactor. Then, heating and depressurization were started in the second reactor, reaching an internal temperature of 240°C and a pressure of 0.2 kPa within 50 minutes. Polymerization was then allowed to proceed until the given stirring power was reached. At the moment when the given power is reached, nitrogen is introduced into the reactor to restore the pressure, and the generated polyester carbonate resin is extruded into the water, cutting the wire into granules.

[0201] The obtained polyester carbonate resin (granules) was vacuum dried at 80°C for 5 hours. A phase retardation film R1 with a thickness of 48 μm was then obtained using a film-forming apparatus equipped with a single-screw extruder (manufactured by Toshiba Machine Co., Ltd., cylinder set temperature: 250°C), a T-die (width 200 mm, set temperature: 250°C), a chilled roll (set temperature: 120–130°C), and a winding machine. The phase retardation film R1 has a Re(550) of 141 nm, a Re(450) / Re(550) ratio of 0.82, and an Nz coefficient of 1.12.

[0202] [Manufacturing Example 2: Fabrication of the first retardation film constituting the first retardation layer]

[0203] Polymerization was carried out using a batch polymerization unit consisting of two vertical stirred reactors equipped with stirring blades and reflux condensers. The feed consisted of 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 Parts by weight (4.47 × 10) -6 (mol). After purging the reactor with nitrogen under reduced pressure, it was heated with a heat medium, and stirring was started when the internal temperature reached 100°C. Forty minutes after the start of heating, the internal temperature was raised to 220°C. While maintaining this temperature, the pressure was reduced, reaching 13.3 kPa 90 minutes after reaching 220°C. Phenol vapor, a byproduct of the polymerization reaction, was introduced into a 110°C reflux condenser, allowing a certain amount of monomer components contained in the phenol vapor to return to the reactor, while the uncondensed phenol vapor was recovered in a 45°C condenser. Nitrogen was introduced into the first reactor to temporarily restore atmospheric pressure, and the oligomerized reaction liquid in the first reactor was transferred to the second reactor. Then, heating and depressurization were started in the second reactor, reaching an internal temperature of 240°C and a pressure of 20 kPa within 40 minutes. The pressure was then further reduced while polymerization continued until the given stirring power was reached. At the moment a given kinetic energy is reached, nitrogen is introduced into the reactor to restore pressure, extruding the generated polyester carbonate into water. The filament is then cut to obtain granules. This resin is called "PC1". The ratio of structural units from each monomer is BPFM / ISB / SPG / DPC = 21.5 / 39.4 / 30.0 / 9.1% by mass. PC1 has a reduced viscosity of 0.46 dL / g, a Mw of 48000, and a refractive index n. D Its properties are: 1.526, melt viscosity: 2480 Pa·s, glass transition temperature: 139℃, and photoelastic modulus: 9×10⁻⁶. -12 [m 2 The wavelength dispersion Re(450) / Re(550) is 0.85.

[0204] Dianal BR80 (manufactured by Mitsubishi Chemical Corporation) was used as the acrylic resin, and the obtained polyester carbonate was extruded and compounded. Polycarbonate granules (99.5 parts by weight) were mixed with BR80 powder (0.5 parts by weight) and fed into a TEX30HSS twin-screw extruder 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 speed of 120 rpm. Furthermore, the extruder was equipped with a vacuum exhaust port, allowing for depressurized devolatilization of the molten resin during extrusion. The granules of the resin composition obtained in this way were vacuum dried at 100°C for more than 6 hours. Then, using a film-forming apparatus equipped with a single-screw extruder (manufactured by Isuzu Chemical Industries Co., Ltd., screw diameter 25mm, cylinder set temperature: 250°C), a T-die (width 300mm, set temperature: 220°C), a chilled roll (set temperature: 120~130°C), and a winding machine, a long, unstretched film with a length of 3m, a width of 200mm, and a thickness of 100μm was produced. The stretching temperature was set to Tg, and the long, unstretched film was stretched at a stretch ratio of 2.4.

[0205] In this way, a retardation film R2 constituting the retardation layer was obtained. The retardation film R2 exhibits refractive index characteristics of nx > ny > nz, with Re(550) of 145 nm and Re(450) / Re(550) of 0.85.

[0206] [Manufacturing Example 3: Fabrication of the first retardation film constituting the first retardation layer]

[0207] A commercially available polycarbonate resin film (stretched film of resin film, manufactured by Teijin Corporation, product name "PURE-ACERM", thickness 50μm) was used as the phase retardation film R3. The Re(550) of the phase retardation film R3 was 147nm, and the Re(450) / Re(550) ratio was 0.90.

[0208] [Manufacturing Example 4: Fabrication of the Second Phase Retardation Film Constituting the Second Phase Retardation Layer]

[0209] A liquid crystal coating solution was prepared by dissolving 20 parts by weight of a side-chain type liquid crystal polymer (weight average molecular weight 5000) represented by the following chemical formula (I) (where 65 and 35 are molar percentages of each structural unit), 80 parts by weight of a polymerizable liquid crystal exhibiting a nematic liquid crystal phase (manufactured by BASF, trade name "Paliocolor LC242"), and 5 parts by weight of a photopolymerization initiator (manufactured by Ciba Specialty Chemicals, trade name "IRGACURE 907") in 200 parts by weight of cyclopentanone. Next, the prepared liquid crystal coating solution was applied to the surface of a norbornene resin film (manufactured by Zeon Corporation, trade name "ZEONEX") serving as a substrate film using a wire-bar coater. The film was then heated and dried at 80°C for 4 minutes to orient the liquid crystal contained within the coating film. Finally, the coating film was cured by ultraviolet irradiation, forming a liquid crystal fixing layer R4 (thickness 0.58 μm) on the substrate film as a second phase retardation film. The liquid crystal fixing layer R4 has an in-plane phase difference Re of 0 nm for light with a wavelength of 550 nm, and a phase difference Rth of -71 nm in the thickness direction (nx = 1.5326, ny = 1.5326, nz = 1.6550). The liquid crystal fixing layer R4 exhibits a refractive index characteristic of nz > nx = ny.

[0210] [Chemical Formula 6]

[0211]

[0212] [Manufacturing Example 5: Preparation of Adhesive]

[0213] (Preparation of acrylic polymer A1)

[0214] 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 added to a four-necked flask equipped with a stirring blade, thermometer, nitrogen inlet tube, and condenser. Further, 0.1 parts of 2,2'-azobisisobutyronitrile (2,2'-Azobisisobutyronitrile) as a polymerization initiator was added along with 100 parts ethyl acetate to 100 parts of this monomer mixture. After nitrogen purging by slowly stirring and introducing nitrogen gas, the liquid temperature in the flask was maintained at approximately 55°C, and the polymerization reaction was carried out for 8 hours to prepare a solution of acrylic polymer A1 with a weight-average molecular weight (Mw) of 2.2 million and Mw / Mn = 3.0.

[0215] (Preparation of adhesive)

[0216] Adhesive PSA1 was obtained by combining 100 parts of the solid component of the acrylic polymer A1 solution with 0.45 parts of trimethylolpropane / toluene diisocyanate adduct (manufactured by Tosoh Corporation, trade name "Coronate L"), 0.1 parts of peroxide crosslinking agent (benzoyl peroxide), 0.2 parts of epoxy-containing silane coupling agent (manufactured by Shin-Etsu Chemical Industry Co., Ltd., trade name "KBM-403") and 0.5 parts of a polyether compound with reactive silyl groups (manufactured by Kaneka Corporation, trade name "Silyl SAT10").

[0217] [Manufacturing Example 6: Preparation of Adhesive]

[0218] (Preparation of acrylic polymer A2)

[0219] A monomer mixture containing 99 parts of butyl acrylate and 1 part of 4-hydroxybutyl acrylate was used. Otherwise, a solution of acrylic polymer A2 with Mw 1.8 million and Mw / Mn = 4.8 was obtained in the same manner as in Manufacturing Example 5.

[0220] (Preparation of adhesive)

[0221] Adhesive PSA2 was obtained by combining 100 parts of the solid component of acrylic polymer A2 solution with 0.1 parts of trimethylolpropane / phenylenedimethyl diisocyanate adduct (manufactured by Tosoh Corporation, trade name "TAKENATE D110N"), 0.3 parts of peroxide crosslinking agent (benzoyl peroxide) and 0.2 parts of epoxy-containing silane coupling agent (manufactured by Shin-Etsu Chemical Industry Co., Ltd., trade name "KBM-403").

[0222] [Manufacturing Example 7: Preparation of Adhesive]

[0223] By changing the amount of D110N to 0.02 parts, the adhesive PSA3 was obtained in the same manner as in Manufacturing Example 6.

[0224] [Manufacturing Example 8: Preparation of Adhesive]

[0225] (Preparation of acrylic polymer A3)

[0226] A monomer mixture containing 76.1 parts butyl acrylate, 19 parts benzyl acrylate, 0.1 parts 4-hydroxybutyl acrylate and 4.8 parts acrylic acid was used. Otherwise, a solution of acrylic polymer A3 with Mw 2.2 million and Mw / Mn = 3.0 was prepared in the same manner as in Manufacturing Example 5.

[0227] (Preparation of adhesive)

[0228] Adhesive PSA4 was obtained by combining 100 parts of the solid component of acrylic polymer A3 solution with 2.5 parts of trimethylolpropane / toluene diisocyanate adduct (manufactured by Tosoh Corporation, trade name "Coronate L"), 0.1 parts of peroxide crosslinking agent (benzoyl peroxide), and 0.2 parts of epoxy-containing oligomer silane coupling agent (manufactured by Shin-Etsu Chemical Industry Co., Ltd., trade name "X-41-1056").

[0229] [Manufacturing Example 9: Preparation of Adhesive]

[0230] (Preparation of acrylic polymer A4)

[0231] A monomer mixture containing 63.1 parts of butyl acrylate, 32 parts of benzyl acrylate, 0.1 parts of 4-hydroxybutyl acrylate and 4.8 parts of acrylic acid was used. Otherwise, a solution of acrylic polymer A4 with Mw 2.2 million and Mw / Mn = 3.2 was prepared in the same manner as in Manufacturing Example 5.

[0232] (Preparation of adhesive)

[0233] Adhesive PSA5 was obtained by combining 100 parts of the solid component of acrylic polymer A4 solution with 2.5 parts of trimethylolpropane / toluene diisocyanate adduct (manufactured by Tosoh Corporation, trade name "Coronate L"), 0.1 parts of peroxide crosslinking agent (benzoyl peroxide), and 0.2 parts of epoxy-containing oligomer silane coupling agent (manufactured by Shin-Etsu Chemical Industry Co., Ltd., trade name "X-41-1056").

[0234] [Manufacturing Example 10: Preparation of Adhesive]

[0235] (Preparation of acrylic polymer A5)

[0236] A monomer mixture containing 94.9 parts butyl acrylate, 0.1 parts 2-hydroxyethyl acrylate, and 5 parts acrylic acid was used. Otherwise, a solution of acrylic polymer A5 with Mw 2.2 million and Mw / Mn = 3.9 was prepared in the same manner as in Manufacturing Example 5.

[0237] (Preparation of adhesive)

[0238] Adhesive PSA6 was obtained by combining 100 parts of the solid component of acrylic polymer A5 solution with 3.0 parts of trimethylolpropane / toluene diisocyanate adduct (manufactured by Tosoh Corporation, trade name "Coronate L"), 0.2 parts of peroxide crosslinking agent (benzoyl peroxide) and 0.075 parts of epoxy-containing silane coupling agent (manufactured by Shin-Etsu Chemical Industry Co., Ltd., trade name "KBM-403").

[0239] [Manufacturing Example 11: Preparation of Adhesive]

[0240] Compared to 100 parts of the solid component of the acrylic polymer A2 solution, 30 parts of a copolymer oligomer (Mw=4700) consisting of 94 parts of butyl acrylate, 4 parts of methyl acrylate, and 2 parts of acrylic acid were added. The amount of D110N was changed to 0.02 parts, and the amount of silane coupling agent was changed to 0.1 parts. Otherwise, the adhesive PSA7 was obtained in the same manner as in Manufacturing Example 6.

[0241] [Manufacturing Example 12: Preparation of Adhesive]

[0242] Adhesive PSA8 was obtained by combining 100 parts of the solid component of the acrylic polymer A1 solution with 12.0 parts of trimethylolpropane / toluene diisocyanate adduct (manufactured by Tosoh Corporation, trade name "Coronate L") and 0.1 parts of epoxy-containing silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBM-403").

[0243] [Manufacturing Example 13: Preparation of Adhesive]

[0244] By changing the amount of Coronate L to 2.5 parts, adhesive PSA9 was obtained in the same manner as in manufacturing example 12.

[0245] [Manufacturing Example 14: Fabrication of Polarizing Film]

[0246] (Making a polarizing filter)

[0247] A 12μm thick polarizer was produced by unidirectionally stretching a 30μm thick polyvinyl alcohol (PVA) resin film (manufactured by KURARAY, product name "PE3000") in the length direction by a roller stretching machine, while simultaneously performing swelling, dyeing, crosslinking, and cleaning treatments, and finally drying treatment.

[0248] Specifically, the swelling treatment was carried out in pure water at 20°C while stretching to 2.2 times. Next, the staining treatment was carried out in an aqueous solution at 30°C with an iodine to potassium iodide weight ratio of 1:7 (adjusted iodine concentration) to achieve a monomer transmittance of 45.0% for the resulting polarizer, while stretching to 1.4 times. Further, the crosslinking treatment employed a two-stage process. The first stage of crosslinking treatment was carried out in an aqueous solution containing boric acid and potassium iodide at 40°C while stretching to 1.2 times. The boric acid content of the first stage crosslinking treatment aqueous solution was 5.0 wt%, and the potassium iodide content was 3.0 wt%. The second stage of crosslinking treatment was carried out in an aqueous solution containing boric acid and potassium iodide at 65°C while stretching to 1.6 times. The boric acid content of the second stage crosslinking treatment aqueous solution was 4.3 wt%, and the potassium iodide content was 5.0 wt%. Finally, the cleaning treatment was carried out in an aqueous solution of potassium iodide at 20°C. The potassium iodide content of the cleaning solution was set to 2.6% by weight. Finally, the polarizing mirror was obtained by drying at 70°C for 5 minutes.

[0249] (Making of polarizing filters)

[0250] A cellulose triacetate film (40 μm thick, manufactured by Konica Minolta Co., Ltd., trade name "KC4UYW") was bonded to one side of the polarizer using a polyvinyl alcohol adhesive, resulting in a polarizer P1 with a protective layer / polarizer structure.

[0251] [Manufacturing Example 15: Fabrication of Polarizing Film]

[0252] (Making a polarizing filter)

[0253] As a thermoplastic resin substrate, a strip-shaped amorphous polyethylene terephthalate copolymer film (thickness: 100 μm) with a Tg of about 75 °C was used, and one side of the resin substrate was subjected to corona treatment.

[0254] 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 resin made by mixing polyvinyl alcohol (degree of polymerization 4200, degree of saponification 99.2 mol%) and acetyl-modified PVA (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "GOHSEFIMER") in a ratio of 9:1, and dissolving the resulting mixture in water.

[0255] The above-mentioned PVA aqueous solution was coated on the corona-treated surface of the resin substrate and dried at 60°C, thereby forming a PVA resin layer with a thickness of 13 μm, and a laminate was fabricated.

[0256] The resulting laminate was unidirectionally stretched to 2.4 times its original length in an oven at 130°C (assisted stretching treatment in a gas atmosphere).

[0257] Next, the laminate was immersed in an insoluble bath at 40°C (an aqueous solution of boric acid prepared by mixing 4 parts by weight of boric acid with 100 parts by weight of water) for 30 seconds (insoluble treatment).

[0258] Next, the polarizer was immersed in a staining bath at 30°C (an iodine aqueous solution prepared by mixing iodine and potassium iodide in a weight ratio of 1:7 relative to 100 parts by weight of water) for 60 seconds while adjusting the concentration to achieve the desired monomer transmittance (Ts) of the final polarizer.

[0259] Next, it was immersed in a crosslinking bath (an aqueous solution of boric acid prepared by mixing 3 parts by weight of potassium iodide and 5 parts by weight of boric acid with 100 parts by weight of water) at a liquid temperature of 40°C for 30 seconds (crosslinking treatment).

[0260] Then, the laminate was immersed in a boric acid aqueous solution (boric acid concentration 4 wt% and potassium iodide concentration 5 wt%) at a liquid temperature of 70°C, and simultaneously stretched unidirectionally along the longitudinal direction (length direction) between rollers with different circumferential speeds to achieve a total stretch ratio of 5.5 times (stretching treatment in aqueous solution).

[0261] Then, the laminate was immersed in a cleaning bath at a liquid temperature of 20°C (an aqueous solution of 100 parts by weight of water and 4 parts by weight of potassium iodide) (cleaning treatment).

[0262] Then, while drying in an oven maintained at approximately 90°C, it comes into contact with SUS heated rollers maintained at a surface temperature of approximately 75°C (drying shrinkage treatment).

[0263] In this way, a polarizer with a thickness of about 5 μm is formed on a resin substrate, resulting in a polarizer with a resin substrate / polarizer structure.

[0264] (Making of polarizing filters)

[0265] A cyclic olefin film (manufactured by Zeon Corporation, Japan, ZF-12, 23 μm) was bonded as a protective layer to the surface of the obtained polarizer (the side opposite to the resin substrate) using a UV-curable adhesive. Specifically, the adhesive was applied to achieve a total thickness of approximately 1.0 μm and then bonded using a roller press. The adhesive was then cured by irradiating the cyclic olefin film side with UV light. Next, the resin substrate was peeled off, resulting in a polarizer P2 having the cyclic olefin film (protective layer) / polarizer configuration.

[0266] (Creating the adhesive layer)

[0267] The prepared adhesive was applied to one side of a polyethylene terephthalate membrane (separator, manufactured by Mitsubishi Chemical Polyester Film Co., Ltd., MRF38) that had been treated with an organosilicon-based release agent, such that the thickness of the dried adhesive layer reached 12 μm. The adhesive coating was then dried to form the first adhesive layer.

[0268] In addition, a second adhesive layer was formed in the same manner as the first adhesive layer, except that the coating was applied in a way that made the thickness of the dried adhesive layer reach 15 μm.

[0269] [Examples 1-9 and Comparative Examples 1-2]

[0270] A first adhesive layer formed on the surface of the diaphragm was transferred to a polarizer to create a polarizer with an adhesive layer. Additionally, a second adhesive layer formed on the surface of the diaphragm was transferred to a retardation film to create a retardation film with an adhesive layer.

[0271] Next, a polarizer with an adhesive layer was fabricated by combining the polarizer, the first retardation film (retardation layer), the second retardation film (liquid crystal fixing layer), and the adhesives (first adhesive layer and second adhesive layer) in the order shown in Table 1. Here, the polarizer and the first retardation layer (retardation film) were bonded such that the absorption axis of the polarizer and the slow axis of the retardation film were at a 45° angle. The resulting polarizer with the retardation layer and adhesive layer was subjected to the aforementioned evaluation of color unevenness, light leakage, and durability. The results, along with the paste offset of the first adhesive layer and the creep value of the second adhesive layer, are shown in Table 1.

[0272]

[0273] [evaluate]

[0274] As can be clearly seen from Table 1, by combining and controlling the paste offset of the first adhesive layer and the creep value of the second adhesive layer, a polarizer with a phase difference layer and an adhesive layer can be obtained for an image display device that can suppress color unevenness and light leakage in a high-temperature environment.

[0275] Industrial applicability

[0276] The polarizer with phase retardation layer and adhesive layer of the present invention is suitable for use in image display devices (typically liquid crystal display devices and organic EL display devices).

Claims

1. A polarizer with a phase retardation layer and an adhesive layer, comprising: Polarizing filters including polarizers, The phase retardation layer of the polarizer is bonded to the polarizer via the first adhesive layer, and The second adhesive layer, which is the outermost layer disposed on the side opposite to the polarizer of the phase difference layer, is used as the outermost layer. The phase retardation layer is formed by stretching a resin film and satisfies the relationship Re(450) < Re(550). The paste offset of the first adhesive layer after a heating test at 85°C for 500 hours was less than 900 μm. The second adhesive layer exhibits a creep value of less than 40 μm at 85°C. The adhesive composition constituting the first adhesive layer and the adhesive composition constituting the second adhesive layer each comprise a (meth)acrylic polymer and a crosslinking agent, wherein the (meth)acrylic polymer contains alkyl (meth)acrylates and hydroxyl-containing monomers. The adhesive composition constituting the second adhesive layer contains at least 1.5 parts by weight of crosslinking agent relative to 100 parts by weight of the base polymer. in, Re(450) and Re(550) are the in-plane phase differences measured at 23°C with light wavelengths of 450 nm and 550 nm, respectively.

2. The polarizer with a phase retardation layer and an adhesive layer according to claim 1, wherein, The Re(550) of the phase retardation layer is 100nm to 200nm, and the angle between the slow axis of the phase retardation layer and the absorption axis of the polarizing mirror is 40° to 50° or 130° to 140°.

3. The polarizer with a phase retardation layer and an adhesive layer according to claim 1 or 2, wherein, The thickness of the phase difference layer is 15μm to 60μm.

4. The polarizer with a phase retardation layer and an adhesive layer according to claim 1 or 2, wherein, The paste offset of the first adhesive layer after a heating test at 85°C for 500 hours is less than 250 μm.

5. The polarizer with a phase retardation layer and an adhesive layer according to claim 1, wherein, The adhesive composition constituting the second adhesive layer contains at least 5 parts by weight of crosslinking agent relative to 100 parts by weight of the base polymer.

6. The polarizer with a phase retardation layer and an adhesive layer according to claim 1 or 2, wherein, The phase retardation layer contains an acrylic resin and a resin with positive refractive index anisotropy. The acrylic resin content is 0.5% to 2.0% by mass. The acrylic resin contains more than 70% by mass of structural units derived from methyl methacrylate and has a weight-average molecular weight (Mw) of 10,000 to 200,000. The resin with positive refractive index anisotropy comprises at least one bonding group selected from carbonate bonds and ester bonds, and at least one structural unit selected from the structural units represented by the following general formula (1) and the following general formula (2). In 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, R 4 ~R 9 Each of the following groups is independently a hydrogen atom, an alkyl group with 1 to 10 substituted or unsubstituted carbon atoms, an aryl group with 4 to 10 substituted or unsubstituted carbon atoms, an acyl group with 1 to 10 substituted or unsubstituted carbon atoms, an alkoxy group with 1 to 10 substituted or unsubstituted carbon atoms, an aryloxy group with 1 to 10 substituted or unsubstituted carbon atoms, an amino group with 1 to 10 substituted or unsubstituted carbon atoms, an ethynyl group with 1 to 10 substituted or unsubstituted carbon atoms, a sulfur atom having a substituent, a silicon atom having a substituent, a halogen atom, a nitro group, or a cyano group, and R 4 ~R 9 R can be either the same or different from each other. 4 ~R 9 At least two adjacent groups may optionally bond to each other to form a ring.

7. The polarizer with a phase retardation layer and an adhesive layer according to claim 1 or 2, wherein, In a humidification TMA test in which the environment was changed in the order of 25℃ / 50%RH, 60℃ / 50%RH, and 60℃ / 85%RH, the dimensional change rate of the phase difference layer in the slow axis direction was less than 0.28%.

8. The polarizer with a phase retardation layer and an adhesive layer according to claim 1 or 2, wherein, Between the phase retardation layer and the second adhesive layer, there is a further phase retardation layer, the refractive index characteristics of which show a relationship of nz > nx = ny.

9. The polarizer with a phase retardation layer and an adhesive layer according to claim 8, wherein, In a humidification TMA test in which the environment was changed in the order of 25℃ / 50%RH, 60℃ / 50%RH, and 60℃ / 85%RH, the dimensional change rate of the phase difference layer in the slow axis direction was less than 0.28% when the additional phase difference layer was attached.

10. An image display device comprising a polarizer with a phase retardation layer and an adhesive layer as described in any one of claims 1 to 9.

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