Phase difference film, polarizing plate with phase difference layer, and method for manufacturing phase difference film

Abstract

Provided are a phase difference film, a polarizing plate with a phase difference layer, and a manufacturing method for a phase difference film. Provided are a phase difference film in which a change in phase difference during a humidity reliability test is suppressed, a change in color phase during a weather resistance test in the ultraviolet region is suppressed, and adhesiveness is excellent, and a polarizing plate with a phase difference layer including the phase difference film. A phase difference film composed of a resin having a birefringence in a prescribed range and having an orientation degree of 30% or more is used.

Description

Technical Field

[0001] This invention relates to a phase retardation film, a polarizing plate with a phase retardation layer, and a method for manufacturing a phase retardation film. Background Technology

[0002] In recent years, the monitor market has seen a demand for reducing monitor brightness to extend battery life and thus suppress heat generation. Therefore, high-transmittance polarizing plates are sought for use in monitors. However, when such high-transmittance polarizing plates are used in monitors, their appearance deteriorates under humid conditions.

[0003] Furthermore, in recent years, displays have been used more frequently in environments exposed to ultraviolet light (e.g., PID (Display Panel) and mobile phones). In particular, for polarizing plates with phase retardation films disposed on the panel side, there is a problem that ultraviolet light can cause changes in the hue of the phase retardation film, thus damaging the quality of the display.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent No. 3325560 Summary of the Invention

[0007] The problem the invention aims to solve

[0008] The present invention was made to solve the above-mentioned problems, and its purpose is to provide a phase difference film that suppresses phase difference changes in humidification reliability tests, suppresses hue changes in ultraviolet weathering tests, and thus has excellent adhesion, and a polarizing plate with a phase difference layer containing the phase difference film.

[0009] Solution for solving the problem

[0010] The phase difference film in the embodiments of the present invention is composed of a resin with a birefringence Δnxy of 0.015 or more, an orientation degree of 30% or more, a front phase difference Re(550) of 100nm to 180nm or 220nm to 340nm, a phase difference change rate of less than 1.5% after being kept at 65°C and 90%RH for 500 hours, and a change rate of b value of less than 1% in the weather resistance test in the ultraviolet region.

[0011] In one embodiment, the resin comprises a polycarbonate-based resin.

[0012] In one embodiment, the polycarbonate resin comprises structural units derived from a dihydroxy compound represented by formula (4) below.

[0013]

[0014] In one embodiment, the polycarbonate resin further comprises a structural unit derived from an alicyclic dihydroxy compound, which is represented by the following general formula (II), R 1 The structure is as shown in (IIb) below, where n = 0.

[0015] HOCH2-R 1 -CH2OH (II)

[0016]

[0017] In one embodiment, the thickness of the phase difference film is 10 μm to 50 μm.

[0018] In another embodiment of the present invention, a polarizing plate with a phase retardation layer is provided. The polarizing plate with the phase retardation layer includes a polarizing element and the aforementioned phase retardation film adhered to at least one side of the polarizing element by means of an adhesive layer. In one embodiment, the phase retardation film is directly adhered to at least one side of the polarizing element by means of the adhesive layer. In another embodiment, the adhesive layer is composed of an active energy radiation-curable adhesive composition.

[0019] According to another aspect of the present invention, a method for manufacturing the aforementioned phase retardation film is provided. This method includes a step of stretching a resin film formed from the aforementioned resin.

[0020] The effects of the invention

[0021] According to an embodiment of the present invention, by stretching a resin film made of a specified resin with a birefringence Δnxy of 0.015 or higher, the orientation degree reaches a certain value or higher. As a result, a phase difference film that suppresses phase difference changes in humidification reliability tests and suppresses hue changes in ultraviolet weathering tests can be realized. Detailed Implementation

[0022] The embodiments of the present invention will be described below, but the present invention is not limited to these embodiments.

[0023] (Definitions of terms and symbols)

[0024] The definitions of terms and symbols used in this specification are as follows.

[0025] (1) Refractive index (nx, ny, nz)

[0026] “nx” is the refractive index in the direction where the in-plane refractive index reaches its maximum (i.e., the slow axis direction), “ny” is the refractive index in the direction orthogonal to the slow axis (i.e., the fast axis direction), and “nz” is the refractive index in the thickness direction.

[0027] (2) In-plane phase difference (Re)

[0028] “Re(λ)” is the in-plane phase difference measured at 23°C using light with a wavelength of λnm. For example, “Re(550)” is the in-plane phase difference measured at 23°C using light with a wavelength of 550nm. When the thickness of the layer (thin film) is set to d (nm), Re(λ) is obtained by the formula Re(λ)=(nx-ny)×d.

[0029] (3) Birefringence (Δnxy)

[0030] The birefringence Δnxy is obtained using the formula: Δnxy=nx-ny.

[0031] A. Phase retardation thin film

[0032] The retardation film of the embodiments of the present invention comprises polycarbonate resin. Therefore, the retardation film of the embodiments of the present invention is representatively a stretched film of polycarbonate resin film. Furthermore, the retardation film of the embodiments of the present invention preferably does not contain ultraviolet absorbers. By not containing ultraviolet absorbers, the retardation film can maintain a neutral hue when applied to an image display device.

[0033] The birefringence Δnxy of the resin constituting the aforementioned phase retardation film is typically 0.015 or higher, preferably 0.018 or higher. The upper limit of the birefringence Δnxy of the aforementioned resin can be, for example, 0.040. By stretching a resin having this birefringence Δnxy, a phase retardation film in which phase difference changes under humidification conditions are suppressed can be obtained.

[0034] The orientation degree of the aforementioned retardation film is 30% or more, preferably 31% or more, and more preferably 32% or more. The upper limit of the orientation degree is, for example, 70%. When the orientation degree of the retardation film is within this range, the adhesion of the retardation film becomes good. This range of orientation degree can be achieved by stretching the aforementioned resin film. The aforementioned orientation degree is measured, for example, by X-ray diffraction (XRD).

[0035] The in-plane phase difference Re(550) of the aforementioned phase retardation film is 100nm~180nm or 220nm~340nm, preferably 120nm~160nm or 240nm~320nm. That is, the phase retardation film can function as a λ / 2 phase retardation plate or a λ / 4 phase retardation plate.

[0036] The phase difference change of the aforementioned phase difference film after being stored at 65°C and 90% humidity for 500 hours (humidification test) is preferably less than 1.5%, more preferably less than 1.4%. The lower limit can be, for example, 0.01%. The aforementioned phase difference change (%) is expressed as |(Re 500-Re0) / Re0|×100(%) represents the phase difference. Re0 is the in-plane phase difference (nm) of the phase difference film before the start of the experiment. 500 The in-plane phase difference (nm) of the phase difference film after the experiment. When the phase difference of the phase difference film varies within this range, the following advantages can be obtained when the phase difference film is applied to an image display device: the hue change caused by the phase difference at various points on the image display device is reduced, and color unevenness on the display can be suppressed.

[0037] In the aforementioned phase retardation film, the change in b-value is suppressed during weathering tests in the ultraviolet region. The rate of change in b-value is 1% or less, preferably 0.95% or less. The lower limit of the rate of change in b-value is, for example, 0%. That is, the phase retardation film can also be well used in applications requiring weather resistance. This advantage is achieved by including the specific polycarbonate resin described later in the phase retardation film.

[0038] The thickness of the aforementioned phase difference film is preferably 10 μm to 50 μm, more preferably 20 μm to 40 μm.

[0039] The preferred moisture permeability of the aforementioned phase difference film is 250 g / m³. 2 • Less than 24 hours, more preferably 150 g / m 2 • Less than 24 hours. The lower limit could be, for example, 1 g / m³. 2 • 24h. When the humidity permeability of the phase difference film is within this range, it has the advantage of being able to suppress phase difference changes under humidified conditions.

[0040] The absolute value of the photoelastic coefficient of the aforementioned phase retardation film is preferably 2 × 10⁻⁶. -11 m 2 / N or less, more preferably 2.0×10 -13 m 2 / N~1.5×10 -11 m 2 / N, further preferably 1.0×10 -12 m 2 / N~1.2×10 -11 m 2 / N. When the absolute value of the photoelastic coefficient is within this range, phase difference changes are less likely to occur even when shrinkage stress is generated during heating. As a result, thermal unevenness in the resulting image display device can be well prevented.

[0041] According to an embodiment of the present invention, as described above, a phase retardation film with a specific range of orientation can be obtained by stretching a resin film composed of a resin having a specific range of birefringence Δnxy. This phase retardation film satisfies the desired in-plane phase difference, thereby suppressing phase difference changes in humidification reliability tests, suppressing hue changes in ultraviolet weathering tests, and exhibiting excellent adhesion. Such a phase retardation film is suitable for applications such as PID (Disclosure Display Panel) and mobile phones.

[0042] B. Constituent Materials

[0043] The aforementioned phase difference film is, as described above, a typically stretched resin film of polycarbonate resin.

[0044] (Polycarbonate resin)

[0045] The polycarbonate resin of the present invention comprises at least structural units derived from a dihydroxy compound having the bonding structure shown in the following structural formula (1), which is manufactured by reacting the dihydroxy compound with a diester in the presence of a polymerization catalyst, wherein the dihydroxy compound comprises at least a dihydroxy compound having at least one intramolecular bonding structure -CH2-O-.

[0046]

[0047] Here, as a dihydroxy compound having the bonding structure shown in structural formula (1), any compound with any structure can be used as long as it has two alcoholic hydroxyl groups, includes a structure with an intramolecular linking group -CH2-O-, and can react with diester carbonate in the presence of a polymerization catalyst to generate polycarbonate. Multiple compounds can be used in combination. Furthermore, as a dihydroxy compound used in the polycarbonate resin of this invention, dihydroxy compounds without the bonding structure shown in structural formula (1) can also be used in combination. Hereinafter, a dihydroxy compound having the bonding structure shown in structural formula (1) will sometimes be abbreviated as dihydroxy compound (A), and a dihydroxy compound without the bonding structure shown in structural formula (1) will sometimes be abbreviated as dihydroxy compound (B).

[0048] (Dihydroxy compound (A))

[0049] In dihydroxy compound (A), the "linking group -CH2-O-" refers to a molecule structure formed by bonding with atoms other than hydrogen atoms. Among this linking group, the atom most preferably capable of bonding with at least an oxygen atom or simultaneously with both carbon and oxygen atoms is a carbon atom. The number of "linking groups -CH2-O-" in dihydroxy compound (A) is preferably one or more, more preferably two to four.

[0050] More specifically, examples of dihydroxy compounds (A) include, for instance, 9,9-bis(4-(2-hydroxyethoxy)phenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-methylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-isopropylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-isobutylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-tert-butylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-cyclohexylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-phenylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3,5-dimethylphenyl)fluorene, 9 Compounds exemplified by 9,9-bis(4-(2-hydroxyethoxy)-3-tert-butyl-6-methylphenyl)fluorene and 9,9-bis(4-(3-hydroxy-2,2-dimethylpropoxy)phenyl)fluorene, whose side chains have aromatic groups and whose main chains have ether groups bonded to the aromatic groups; bis[4-(2-hydroxyethoxy)phenyl]methane, bis[4-(2-hydroxyethoxy)phenyl]diphenylmethane, 1,1-bis[4-(2-hydroxyethoxy)phenyl]ethane, 1,1-bis[4-(2-hydroxyethoxy)phenyl]-1-phenylethane, 2,2-bis[4-(2-hydroxyethoxy)phenyl]propane, 2,2-bis[4-(2-hydroxyethoxy)-3-methylphenyl]propane, 2,2- bis[3,5-dimethyl-4-(2-hydroxyethoxy)phenyl]propane, 1,1-bis[4-(2-hydroxyethoxy)phenyl]-3,3,5-trimethylcyclohexane, 1,1-bis[4-(2-hydroxyethoxy)phenyl]cyclohexane, 1,4-bis[4-(2-hydroxyethoxy)phenyl]cyclohexane, 1,3-bis[4-(2-hydroxyethoxy)phenyl]cyclohexane, 2,2-bis[4-(2-hydroxyethoxy)-3-phenylphenyl]propane, 2,2-bis[(2-hydroxyethoxy)-3-isopropylphenyl]propane, 2,2-bis[3-tert-butyl-4-(2-hydroxyethoxy)phenyl]propane, 2,2-bis[4-(2-hydroxyethoxy)phenyl]butane, 2,2 Bis(hydroxyalkoxyaryl)alkanes exemplified by bis[4-(2-hydroxyethoxy)phenyl]-4-methylpentane, 2,2-bis[4-(2-hydroxyethoxy)phenyl]octane, 1,1-bis[4-(2-hydroxyethoxy)phenyl]decane, 2,2-bis[3-bromo-4-(2-hydroxyethoxy)phenyl]propane, and 2,2-bis[3-cyclohexyl-4-(2-hydroxyethoxy)phenyl]propane; and bis(hydroxyalkoxyaryl)cycloalkanes exemplified by 1,1-bis[4-(2-hydroxyethoxy)phenyl]cyclohexane, 1,1-bis[3-cyclohexyl-4-(2-hydroxyethoxy)phenyl]cyclohexane, and 1,1-bis[4-(2-hydroxyethoxy)phenyl]cyclopentane.Dihydroxyalkoxy diaryl ethers exemplified by 4,4'-bis(2-hydroxyethoxy)diphenyl ether and 4,4'-bis(2-hydroxyethoxy)-3,3'-dimethyldiphenyl ether; dihydroxyalkoxy aryl sulfides exemplified by 4,4'-bis(2-hydroxyethoxyphenyl)sulfide and 4,4'-bis[4-(2-dihydroxyethoxy)-3-methylphenyl]sulfide; dihydroxyalkoxy aryl sulfides exemplified by 4,4'-bis(2-hydroxyethoxyphenyl)sulfoxide and 4,4'-bis[4-(2-dihydroxyethoxy)-3-methylphenyl]sulfoxide; 4,4'-bis(2-hydroxyethoxyphenyl)sulfone and 4,4'-bis[4-(2-dihydroxyethoxy)- Dihydroxyalkoxyaryl sulfones such as 3-methylphenyl]sulfone; 1,4-dihydroxyethoxybenzene, 1,3-dihydroxyethoxybenzene, 1,2-dihydroxyethoxybenzene, 1,3-bis[2-[4-(2-hydroxyethoxy)phenyl]propyl]benzene, 1,4-bis[2-[4-(2-hydroxyethoxy)phenyl]propyl]benzene, 4,4'-bis(2-hydroxyethoxy)biphenyl, 1,3-bis[4-(2-hydroxyethoxy)phenyl]-5,7-dimethyladamantane, anhydrous sugar alcohols represented by dihydroxy compounds shown in formula (4) below; and compounds having cyclic ether structures such as spirodiol shown in general formula (6) below, which may be used alone or in combination of two or more.

[0051]

[0052] These dihydroxy compounds (A) can be used alone or in combination of two or more. In this invention, isosorbide, isomannitol, and isoidolitool, which are stereoisomers, can be listed as dihydroxy compounds represented by the aforementioned formula (4). They can be used alone or in combination of two or more.

[0053] It should be noted that, among the dihydroxy compound (A), isosorbide, obtained by dehydration condensation of sorbitol, which is produced from various readily available and abundant starches, is the most preferred choice from the perspectives of ease of acquisition and manufacture, optical properties, and formability. In this invention, isosorbide is suitable as the dihydroxy compound (A).

[0054] (Dihydroxy compound (B))

[0055] In this invention, dihydroxy compound (B) can be used as the dihydroxy compound, which is a dihydroxy compound other than dihydroxy compound (A). As dihydroxy compound (B), for example, alicyclic dihydroxy compounds, aliphatic dihydroxy compounds, oxoalkyl diols, aromatic dihydroxy compounds, and diols having cyclic ether structures can be used as dihydroxy compounds that form structural units of polycarbonate, and can be used together with dihydroxy compound (A) and, for example, dihydroxy compound shown in formula (4).

[0056] The alicyclic dihydroxy compound used in this invention is not particularly limited, but compounds typically containing a five-membered or six-membered ring structure are preferred. Furthermore, the six-membered ring structure can be fixed into a chair or boat shape by covalent bonds. By making the alicyclic dihydroxy compound a five- or six-membered ring structure, the heat resistance of the resulting polycarbonate can be improved. The alicyclic dihydroxy compound typically contains 70 or less carbon atoms, preferably 50 or less, and more preferably 30 or less. A higher number of carbon atoms results in higher heat resistance, but makes it difficult to synthesize or purify, or increases costs. A smaller number of carbon atoms makes it easier to purify and obtain.

[0057] As alicyclic dihydroxy compounds containing a five-membered ring structure or a six-membered ring structure that can be used in this invention, specifically, alicyclic dihydroxy compounds represented by the following general formula (II) or (III) can be listed.

[0058] HOCH2-R 1 -CH2OH (II)

[0059] HO-R 2 -OH (III)

[0060] In equations (II) and (III), R 1 R 2 These represent cycloalkylene groups with 4 to 20 carbon atoms, respectively.

[0061] Regarding cyclohexanediethanol, which is an alicyclic dihydroxy compound represented by the above general formula (II), including R in general formula (II) 1 Using the following general formula (IIa) (where R is...) 3 Various isomers (represented by alkyl groups or hydrogen atoms with 1 to 12 carbon atoms) are listed. Specific examples of such isomers include 1,2-cyclohexanediethanol, 1,3-cyclohexanediethanol, and 1,4-cyclohexanediethanol.

[0062]

[0063] Regarding tricyclodecanediethanol and pentacyclopentadecanedimethanol, which are alicyclic dihydroxy compounds represented by the above general formula (II), including R in general formula (II)1 Various isomers are represented by the following general formula (IIb) (where n represents 0 or 1).

[0064]

[0065] Regarding decahydronaphthalenediethanol or tricyclotetradecanediethanol, which are alicyclic dihydroxy compounds of the above general formula (II), including R in general formula (II) 1 Various isomers are represented by the following general formula (IIc) (where m represents 0 or 1). Specifically, examples of such isomers include 2,6-decahydronaphthalenediethanol, 1,5-decahydronaphthalenediethanol, and 2,3-decahydronaphthalenediethanol.

[0066]

[0067] Furthermore, regarding norbornanediethanol, which is an alicyclic dihydroxy compound represented by the above general formula (II), including R in general formula (II) 1 Various isomers are represented by the following general formula (IId). Specifically, examples of such isomers include 2,3-norbornanediethanol and 2,5-norbornanediethanol.

[0068]

[0069] Regarding adamantanediethanol, which is an alicyclic dihydroxy compound represented by general formula (II), including R in general formula (II) 1 Various isomers are represented by the following general formula (IIe). Specifically, examples of such isomers include 1,3-adamantanediethanol.

[0070]

[0071] Furthermore, cyclohexanediol, as an alicyclic dihydroxy compound represented by general formula (III), includes R in general formula (III). 2 Using the following general formula (IIIa) (where R is...) 3 Various isomers (represented by alkyl groups or hydrogen atoms with 1 to 12 carbon atoms) are listed. Specific examples of such isomers include 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, and 2-methyl-1,4-cyclohexanediol.

[0072]

[0073] Regarding tricyclic decanediol and pentacyclic pentadecanediol, which are alicyclic dihydroxy compounds of the above general formula (III), including R in general formula (III) 2 Various isomers are represented by the following general formula (IIIb) (where n represents 0 or 1).

[0074]

[0075] Regarding decahydronaphthalene glycol or tricyclic tetradecanediol, which are alicyclic dihydroxy compounds of the above general formula (III), including R in general formula (III) 2 Various isomers are represented by the following general formula (IIIc) (where m represents 0 or 1). Specifically, 2,6-decahydronaphthalenediol, 1,5-decahydronaphthalenediol, 2,3-decahydronaphthalenediol, etc., can be used as such isomers.

[0076]

[0077] Regarding norbornanediol, which is an alicyclic dihydroxy compound of the above general formula (III), including R in general formula (III) 2 Various isomers represented by the following general formula (IIId). Specifically, 2,3-norbornanediol, 2,5-norbornanediol, etc., can be used as such isomers.

[0078]

[0079] Regarding adamantanediol, which is an alicyclic dihydroxy compound of the above general formula (III), including R in general formula (III) 2 Various isomers represented by the following general formula (IIIe). Specifically, 1,3-adamantanediol and the like can be used as such isomers.

[0080]

[0081] Among the specific examples of the aforementioned alicyclic dihydroxy compounds, cyclohexanediethanol, tricyclodecanediethanol, adamantanediol, and pentacyclopentadecanedimethanol are particularly preferred. From the viewpoint of ease of acquisition and processing, 1,4-cyclohexanediethanol, 1,3-cyclohexanediethanol, 1,2-cyclohexanediethanol, and tricyclodecanediethanol are preferred. In this invention, tricyclodecanediethanol is suitable as the dihydroxy compound (B).

[0082] Examples of aliphatic dihydroxy compounds that can be used in this invention include ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 1,5-heptanediol, and 1,6-hexanediol. Examples of oxoalkylene glycols that can be used in this invention include diethylene glycol, triethylene glycol, tetraethylene glycol, and polyethylene glycol.

[0083] Examples of aromatic dihydroxy compounds that can be used in this invention include, for example, 2,2-bis(4-hydroxyphenyl)propane [= bisphenol A], 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 2,2-bis(4-hydroxy-3,5-diethylphenyl)propane, 2,2-bis(4-hydroxy-(3,5-diphenyl)phenyl)propane, 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane, 2,2-bis(4-hydroxyphenyl)pentane, 2,4'-dihydroxy-diphenylmethane, bis(4-hydroxyphenyl)methane, bis(4-hydroxy-5-nitrophenyl)methane, and 1,1-bis(4-hydroxyphenyl)propane. 3,3-Bis(4-hydroxyphenyl)pentane, 1,1-Bis(4-hydroxyphenyl)cyclohexane, bis(4-hydroxyphenyl)sulfone, 2,4'-dihydroxydiphenylsulfone, bis(4-hydroxyphenyl)sulfide, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3,3'-dichlorodiphenyl ether, 4,4'-dihydroxy-2,5-diethoxydiphenyl ether, 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy-2-methyl)phenyl]fluorene, 9,9-bis(4-hydroxyphenyl)fluorene, 9,9-bis(4-hydroxy-2-methylphenyl)fluorene.

[0084] Examples of diols with cyclic ether structures that can be used in this invention include spirodiols and dioxanediols. It should be noted that the above-described examples are examples of alicyclic dihydroxy compounds, aliphatic dihydroxy compounds, oxoalkylene diols, aromatic dihydroxy compounds, and diols with cyclic ether structures that can be used in this invention, but are not limited to them at all. One or more of these compounds can be used in conjunction with the dihydroxy compound shown in formula (4).

[0085] By using these dihydroxy compounds (B), effects such as improved flexibility, enhanced heat resistance, and improved formability can be achieved, which are consistent with the intended use. The proportion of dihydroxy compound (A), such as the dihydroxy compound shown in formula (4), relative to all dihydroxy compounds constituting the polycarbonate resin of this invention is not particularly limited, but is preferably 10 mol% or more, more preferably 40 mol% or more, further preferably 60 mol% or more, and preferably 90 mol% or less, more preferably 80 mol% or less, and further preferably 70 mol% or less. If the proportion of structural units derived from other dihydroxy compounds is too high, properties such as optical properties may sometimes be reduced.

[0086] Among the other dihydroxy compounds mentioned above, when using alicyclic dihydroxy compounds, the total proportion of dihydroxy compound (A), such as the dihydroxy compound shown in formula (4), and alicyclic dihydroxy compounds relative to all dihydroxy compounds constituting polycarbonate is not particularly limited, but is preferably 80 mol% or more, more preferably 90 mol% or more, and even more preferably 95 mol% or more.

[0087] Furthermore, the ratio of structural units derived from dihydroxy compound (A), such as those of formula (4), to structural units derived from alicyclic dihydroxy compounds in the polycarbonate resin of the present invention can be selected in any ratio. Preferably, the ratio of structural units derived from dihydroxy compound (4) to structural units derived from alicyclic dihydroxy compound is 1:99 to 99:1 (mol%), and particularly preferably, the ratio of structural units derived from dihydroxy compound (4) to structural units derived from alicyclic dihydroxy compound is 10:90 to 90:10 (mol%). If, compared to the above range, there are more structural units derived from dihydroxy compound (4) and fewer structural units derived from alicyclic dihydroxy compound, there is a tendency for the color to be easily achieved. Conversely, if there are fewer structural units derived from dihydroxy compound (4) and more structural units derived from alicyclic dihydroxy compound, there is a tendency for the molecular weight to be difficult to increase.

[0088] Furthermore, when using aliphatic dihydroxy compounds, oxoalkylene glycols, aromatic dihydroxy compounds, or diols with cyclic ether structures, the proportion of dihydroxy compound (A), such as the dihydroxy compound shown in formula (4), and the total of these various dihydroxy compounds relative to all dihydroxy compounds constituting polycarbonate is not particularly limited and can be selected in any proportion. In addition, the proportion of structural units derived from dihydroxy compound (A), such as the dihydroxy compound shown in formula (4), and structural units derived from these various dihydroxy compounds is not particularly limited and can be selected in any proportion.

[0089] Details of polycarbonate resins are described, for example, in Japanese Patent Application Publication No. 2012-31370 (Japanese Patent No. 5448264). The description in that patent document is incorporated herein by reference.

[0090] C. Methods for manufacturing phase retardation thin films

[0091] The method for manufacturing a phase retardation film according to an embodiment of the present invention includes stretching a resin film. The resin film is a film formed from the polycarbonate resin described in section B above.

[0092] In one embodiment, the retardation film is manufactured by unidirectional stretching of a resin film or unidirectional stretching at a fixed end. A specific example of unidirectional stretching at a fixed end is a method in which the resin film is stretched along its length direction while simultaneously being stretched in its width direction (lateral direction). The stretching ratio is preferably 1.1 to 3.5 times, more preferably 1.5 to 3.0 times, and even more preferably 2.0 to 2.5 times. By stretching the resin film formed from the polycarbonate resin described in section B at this stretching ratio, the solvent permeability of the retardation film changes, forming a compatible layer with the adhesive layer, and the adhesive strength is improved. This phenomenon is more pronounced when the phase difference value of the retardation film is higher. That is, by stretching a specific polycarbonate resin at the stretching ratio described above, the phase difference change of the retardation film under humidification conditions can be significantly suppressed.

[0093] The stretching temperature of the aforementioned resin film is preferably Tg-30℃ to Tg+30℃, more preferably Tg-15℃ to Tg+15℃, and even more preferably Tg-10℃ to Tg+10℃. By stretching at this temperature, a phase retardation film with suitable characteristics can be obtained in this invention. It should be noted that Tg is the glass transition temperature of the constituent material of the film.

[0094] D. Polarizing plate with phase retardation layer

[0095] The retardation film described in items A through C above can be provided as a laminate with other optical films and / or optical components. In one embodiment, the retardation film can be provided as a laminate with a polarizing plate (a polarizing plate with a retardation layer). Therefore, the present invention includes a polarizing plate with a retardation layer having the above-described retardation film. The polarizing plate with a retardation layer according to an embodiment of the present invention comprises a polarizing plate and a retardation layer made of the above-described retardation film. In the retardation film, the angle between the absorption axis of the polarizing element of the polarizing plate and the slow axis of the retardation film can be appropriately set according to the application and purpose. In one embodiment, the angle is preferably 40° to 50°, more preferably 42° to 48°, and even more preferably about 45°.

[0096] A polarizing plate with a phase retardation layer typically includes a polarizing element and the aforementioned phase retardation film adhered to at least one side of the polarizing element by means of an adhesive layer. As described above, the phase retardation film exhibits excellent adhesion to the polarizing element.

[0097] As a representative example of an adhesive composition constituting the aforementioned adhesive layer, an active energy radiation-curable adhesive composition is an active energy radiation-curable adhesive composition. This active energy radiation-curable adhesive composition comprises an active energy radiation-curable compound.

[0098] The active energy ray-curable adhesive composition of the present invention is, for example, an active energy ray-curable adhesive composition containing active energy ray-curable compounds (A), (B), and (C) as curing components, and when the total amount of the composition is set to 100% by weight, it contains an SP value of 29.0 (MJ / m³). 3 ) more than 1 / 2 and 32.0 (MJ / m 3 (A) 0.0–4.0% by weight of active energy ray-cured compound (A) with an SP value of 18.0 (MJ / m²) 3 More than 1 / 2 but less than 21.0 (MJ / m³) 3 The active energy ray-cured compound (B) was 5.0–98.0% by weight, with an SP value of 21.0 (MJ / m²). 3 ) more than 1 / 2 and 26.0 (MJ / m 3 The active energy ray-curable compound (C) is less than 1 / 2 in weight, and the content is 5.0 to 98.0% by weight. It should be noted that in this invention, "total composition" refers to the total amount of various initiators and / or additives included in addition to the active energy ray-curable compound.

[0099] The active energy radiation-curable compound (A) only needs to have free radical polymerizable groups such as (meth)acrylate groups and an SP value of 29.0 (MJ / m²). 3 ) more than 1 / 2 and 32.0 (MJ / m 3 Compounds with a content of 1 / 2 or less can be used without limitation. Specific examples of active energy ray-curable compounds (A) include hydroxyethyl acrylamide (SP value 29.5) and N-hydroxymethyl acrylamide (SP value 31.5). It should be noted that in this invention, (meth)acrylate groups refer to acrylate groups and / or methacrylate groups.

[0100] Active energy radiation-cured compound (B) only needs to have free radical polymerizable groups such as (meth)acrylate groups and an SP value of 18.0 (MJ / m²). 3 More than 1 / 2 but less than 21.0 (MJ / m³) 3Compounds of 1 / 2 can be used without restriction. Specific examples of active energy ray-cured compounds (B) include tripropylene glycol diacrylate (SP value 19.0), 1,9-nonanediol diacrylate (SP value 19.2), tricyclodecanediethanol diacrylate (SP value 20.3), cyclic trimethylolpropane formal acrylate (SP value 19.1), dioxanediol diacrylate (SP value 19.4), and EO-modified diglycerol tetraacrylate (SP value 20.9). It should be noted that, as an active energy ray curing compound (B), commercially available products can also be used, such as ARONIX M-220 (manufactured by Toa Synthetic Co., Ltd., SP value 19.0), Light Acrylate 1,9ND-A (manufactured by Kyoeisha Chemical Co., Ltd., SP value 19.2), Light Acrylate DGE-4A (manufactured by Kyoeisha Chemical Co., Ltd., SP value 20.9), Light Acrylate DCP-A (manufactured by Kyoeisha Chemical Co., Ltd., SP value 20.3), SR-531 (manufactured by SARTOMER Co., Ltd., SP value 19.1), CD-536 (manufactured by SARTOMER Co., Ltd., SP value 19.4), etc.

[0101] Active energy radiation-cured compound (C) only needs to have free radical polymerizable groups such as (meth)acrylate groups and an SP value of 21.0 (MJ / m²). 3 ) more than 1 / 2 and 26.0 (MJ / m 3 Compounds with a content of 1 / 2 or less can be used without restriction. Specific examples of active energy ray-curable compounds (C) include acrylamide (SP value 22.9), N-methoxymethylacrylamide (SP value 22.9), and N-ethoxymethylacrylamide (SP value 22.3). It should be noted that commercially available products can also be used as active energy ray-curable compounds (C), such as ACMO (manufactured by KOHJIN Co., Ltd., SP value 22.9), Wasmer 2MA (manufactured by Kasano Kosan Co., Ltd., SP value 22.9), Wasmer EMA (manufactured by Kasano Kosan Co., Ltd., SP value 22.3), and Wasmer 3MA (manufactured by Kasano Kosan Co., Ltd., SP value 22.4).

[0102] Details of the adhesive composition are described, for example, in Japanese Patent Application Publication No. 2019-147865. The description in that patent document is incorporated herein by reference. By combining the adhesive layer and the retardation film described above, a compatible layer is formed between the retardation film and the adhesive layer, resulting in good adhesion of the retardation film. Therefore, in the manufacture of a polarizing plate with a retardation layer, it becomes unnecessary to provide an easy-adhesive layer between the retardation film and the adhesive layer. Therefore, in the aforementioned polarizing plate with a retardation layer, it is preferable that the retardation film is directly adhered to at least one side of the polarizing element by means of the adhesive layer. This polarizing plate with a retardation layer, which does not have an easy-adhesive layer, can effectively suppress phase difference changes under humidification conditions.

[0103] A protective layer may also be provided on at least one side of the polarizing element. Furthermore, an adhesive layer and a separator may be provided on the side of the polarizing plate with the phase retardation layer opposite to the viewing side. The polarizing element, protective layer, adhesive layer, and separator can be constructed using methods known in the art, and therefore detailed descriptions are omitted.

[0104] Example

[0105] The present invention will be specifically described below through examples, but the present invention is not limited to these examples. It should be noted that the methods for measuring and evaluating each characteristic are as follows.

[0106] (1) In-plane phase difference

[0107] The phase difference films obtained in the examples and comparative examples were cut into 4 cm long and 4 cm wide pieces as test samples. The in-plane phase difference Re(550) was measured using Axometrics' "Axoscan" product.

[0108] (2) Refractive index and birefringence Δnxy

[0109] The measurements were performed using an Abbe refractometer (DR-M2, Atago). The measurements were conducted at 23°C.

[0110] (3) Thickness

[0111] Thicknesses below 10 μm were measured using an interferometric film thickness gauge (manufactured by Otsuka Electronics Co., Ltd., product name "MCPD-9800"). Thicknesses exceeding 10 μm were measured using a digital micrometer (manufactured by ANRITSU Co., Ltd., product name "KC-351C").

[0112] (4) Orientation

[0113] The orientation degree was determined by X-ray diffraction (XRD) using the phase difference films obtained in the examples and comparative examples.

[0114] (5) Humidification phase difference change

[0115] The polarizing plates with phase retardation layers obtained in the examples and comparative examples were cut into 5cm × 5cm pieces. Adhesive was applied to one side by hand roller, and the adhesive side was then attached to one side of the alkali glass to obtain test pieces. The test pieces were stored in an oven at 65°C and 90% humidity for 500 hours (humidification test), and the phase difference change (%) before and after the test was calculated. Cases with a phase difference change of less than 1.5% were recorded as good, and cases with a phase difference change of more than 1.5% were recorded as poor.

[0116] (6) Parallel hue a value and b value

[0117] The parallel hue values ​​a and b of the phase difference films obtained in the examples and comparative examples were determined. Measurements were performed using a spectrophotometer (manufactured by Nippon Spectrophotometer Co., Ltd., trade name "V-7100"). A change rate of less than 1% between the b-value before immersion in the ultraviolet fading tester (device name: Ultraviolet Fading Tester U48, manufactured by Suga Test Instruments Co., Ltd.) and the b-value after 100 hours was recorded as "good," and a change rate exceeding 1% was recorded as "bad."

[0118] (7) Adhesion

[0119] The retardation film obtained in the examples and comparative examples was bonded to a polarizing element to obtain a laminate. The resulting laminate was cut into pieces 200 mm in the direction parallel to the stretching direction of the polarizing element and 15 mm in the orthogonal direction, and the laminate was then bonded to a glass plate. A cut was made between the retardation film and the polarizing element using a cutter, and the retardation film and the polarizing element were peeled at a peel speed of 1000 mm / min along a 90-degree direction using a TENSILON RTC universal testing machine (manufactured by A&D Corporation), and the peel strength (N / 15 mm) was measured. A peel strength of 1 N / 15 mm or higher was recorded as good, and a peel strength of less than 1 N / 15 mm was recorded as poor.

[0120] [Example 1]

[0121] 1. Fabrication of resin film

[0122] In a reaction vessel, relative to 81.98 parts by mass of isosorbide (hereinafter sometimes abbreviated as "ISB"), 47.19 parts by mass of tricyclodecanediethanol (hereinafter sometimes abbreviated as "TCDDM"), 175.1 parts by mass of diphenyl carbonate (hereinafter sometimes abbreviated as "DPC"), and 0.979 parts by mass of a 0.2% by mass aqueous solution of cesium carbonate as a catalyst, the reaction is carried out under a nitrogen atmosphere. As the first stage of the reaction, the heating tank temperature is raised to 150°C, and the raw materials are dissolved by stirring as needed (approximately 15 minutes). Next, the pressure is set from atmospheric pressure to 13.3 kPa, and the heating tank temperature is raised to 190°C over 1 hour, while the generated phenol is removed from the reaction vessel. After maintaining the entire reaction vessel at 190°C for 15 minutes, as the second stage of the reaction, the pressure inside the reaction vessel is set to 6.67 kPa, and the heating tank temperature is raised to 230°C over 15 minutes, while the generated phenol is removed from the reaction vessel. As the stirring torque of the mixer gradually increased, the temperature was raised to 250°C over 8 minutes. Then, to remove the generated phenol, the pressure inside the reaction vessel was brought down to below 0.200 kPa. After reaching the specified stirring torque, the reaction was terminated, and the resulting reactants were extruded into water to obtain polycarbonate resin granules. The birefringence Δnxy of the obtained polycarbonate resin was 0.015. After vacuum drying the obtained polycarbonate resin at 100°C for 12 hours, a 90 μm thick polycarbonate resin film was produced using a film forming apparatus equipped with a single-screw extruder (manufactured by Toshiba Machine Co., Ltd., barrel set temperature: 250°C), a T-die (width 1700 mm, set temperature: 250°C), a casting roller (set temperature: 60°C), and a winding machine.

[0123] 2. Fabrication of phase retardation thin films

[0124] Using a simultaneous biaxial stretching machine, the unstretched polycarbonate resin film was subjected to preheating and simultaneous biaxial stretching to obtain a phase retardation film. The preheating temperature was set to 140°C, the stretching temperature was set to 138°C, and the stretching ratio in the length direction was set to 2.4 times. The obtained phase retardation film had an orientation degree of 31.1%, an in-plane phase difference Re(550) of 140 nm, a humidification phase difference change rate of 1.21%, and a thickness of 40 μm. The obtained phase retardation film was evaluated using methods (6) and (7) above. The results are shown in Table 1.

[0125] 3. Fabrication of polarizing plates

[0126] As the resin substrate, a strip-shaped amorphous polyethylene terephthalate copolymer film (thickness: 100 μm) with a Tg of about 75 °C was used, and corona treatment was performed on one side of the resin substrate.

[0127] Potassium iodide was added to 100 parts by weight of a PVA-based resin, which was prepared 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 "GOSEFIMER") in a ratio of 9:1. The resulting substance was dissolved in water to prepare a PVA aqueous solution (coating solution).

[0128] The above-mentioned PVA aqueous solution is coated on the corona-treated surface of the resin substrate and dried at 60°C to form a PVA-based resin layer with a thickness of 13 μm, thereby producing a laminate.

[0129] The resulting laminate was stretched unidirectionally in the longitudinal direction (length direction) to 2.4 times its original size in a heating furnace at 130°C (air-assisted stretching treatment).

[0130] Next, the laminate was immersed in an insoluble bath (an aqueous solution of boric acid prepared by mixing 4 parts by weight of boric acid with 100 parts by weight of water) at a liquid temperature of 40°C for 30 seconds (insoluble treatment).

[0131] Next, the polarizer is immersed in a dyeing 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, so that the monomer transmittance (Ts) of the final polarizer is the desired value (dyeing treatment).

[0132] Next, it is immersed in a crosslinking bath at a liquid temperature of 40°C (an aqueous solution of boric acid prepared by mixing 3 parts by weight of potassium iodide and 5 parts by weight of boric acid relative to 100 parts by weight of water) for 30 seconds (crosslinking treatment).

[0133] Then, the laminated body is immersed in a boric acid aqueous solution (boric acid concentration 4% by weight, potassium iodide concentration 5% by weight) at a liquid temperature of 70°C and then stretched unidirectionally along the longitudinal direction (length direction) between rollers with different circumferential speeds, so that the total stretch ratio becomes 5.5 times (water stretching treatment).

[0134] Then, the laminate is immersed in a cleaning bath at a liquid temperature of 20°C (an aqueous solution of 4 parts by weight of potassium iodide mixed with 100 parts by weight of water) (cleaning treatment).

[0135] Then, while drying in a heating oven at approximately 90°C, it is brought into contact with SUS heating rollers at a surface temperature of approximately 75°C (drying shrinkage treatment).

[0136] Thus, a polarizing element with a thickness of about 5 μm is formed on the resin substrate, resulting in a polarizing plate having a resin substrate / polarizing element structure.

[0137] Next, a cyclic olefin film (manufactured by Zeon Corporation, Japan, trade name "zeonor") is bonded as a protective layer to the side of the obtained polarizer opposite to the resin substrate using a UV-curable adhesive. Specifically, the adhesive is applied with a total thickness of approximately 1.0 μm using a roller. Then, UV light is irradiated from the cyclic olefin film side to cure the adhesive. The resin substrate is then peeled off to obtain a polarizing plate consisting of a cyclic olefin film (protective layer) and a polarizer. The in-plane phase difference of this protective layer is 135 nm. The angle between the slow axis of the protective layer and the absorption axis of the polarizer is assumed to be substantially parallel.

[0138] 4. Fabrication of a polarizing plate with a phase retardation layer

[0139] On one side of the aforementioned retardation film, an active energy ray-curable adhesive composition was coated with an MCD coating machine (manufactured by Fuji Machinery Co., Ltd.) to a thickness of 0.7 μm, and then bonded to the surface of the polarizing element of the aforementioned polarizing plate using a roller. The active energy ray-curable adhesive composition was obtained by mixing 40 parts of "LightAcrylate1.9ND-A" manufactured by Kyoei Chemical Co., Ltd., 20 parts of "Aronix M-5700" manufactured by Toa Synthetic Co., Ltd., and 10 parts of "ARUFON UP1190" manufactured by Toa Synthetic Co., Ltd., and stirring at 50°C for 1 hour. Then, visible light was irradiated from the bonded retardation film side using an active energy ray irradiation device to cure the active energy ray-curable adhesive, followed by hot air drying at 70°C for 3 minutes to obtain a polarizing plate with a retardation layer. The angle between the absorption axis of the polarizing element and the slow axis of the retardation film was set to 45°. The resulting polarizing plate with the phase difference layer was used for the evaluation described in (5) above. The results are shown in Table 1.

[0140] [Example 2]

[0141] A phase retardation film was obtained by setting the thickness to 30 μm and otherwise operating in the same manner as in Example 1. The obtained phase retardation film had an orientation degree of 31.9%, an in-plane phase difference Re(550) of 140 nm, and a humidification phase difference change rate of 1.15%. Furthermore, using the obtained phase retardation film in the same manner as in Example 1, a polarizer with a phase retardation layer was obtained. The obtained phase retardation film and the polarizer with the phase retardation layer were subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0142] [Example 3]

[0143] The birefringence Δnxy of the polycarbonate resin was set to 0.018, the preheating temperature to 138°C, and the stretching temperature to 135°C. Otherwise, the procedure was the same as in Example 1 to obtain a phase retardation film. The obtained phase retardation film had an orientation degree of 35.7%, an in-plane phase difference Re(550) of 270 nm, and a humidification phase difference change rate of 1.29%. Furthermore, using the obtained phase retardation film in the same manner as in Example 1, a polarizer with a phase retardation layer was obtained. The obtained phase retardation film and the polarizer with the phase retardation layer were evaluated in the same way as in Example 1. The results are shown in Table 1.

[0144] [Example 4]

[0145] The birefringence Δnxy of the polycarbonate resin was set to 0.024, the thickness to 30 μm, the stretching ratio to 2.5 times, and the preheating temperature to 138°C and the stretching temperature to 135°C. Otherwise, the procedure was the same as in Example 1 to obtain a phase retardation film. The obtained phase retardation film had an orientation degree of 34.6%, an in-plane phase difference Re(550) of 260 nm, and a humidification phase difference change rate of 1.31%. Furthermore, using the obtained phase retardation film in the same manner as in Example 1, a polarizer with a phase retardation layer was obtained. The obtained phase retardation film and the polarizer with the phase retardation layer were evaluated in the same way as in Example 1. The results are shown in Table 1.

[0146] [Comparative Example 1]

[0147] The birefringence Δnxy of the polycarbonate resin was set to 0.016, and the stretching ratio in the length direction was set to 2.12 times. Otherwise, the procedure was the same as in Example 1 to obtain a phase retardation film. The obtained phase retardation film had an orientation degree of 29.4%, an in-plane phase difference Re(550) of 140 nm, and a humidification phase difference change rate of 2.81%. Furthermore, an easy-to-bond layer was formed, and otherwise, the procedure was the same as in Example 1, using the obtained phase retardation film to fabricate a polarizing plate with a phase retardation layer. The obtained phase retardation film and the polarizing plate with the phase retardation layer were evaluated in the same way as in Example 1. The results are shown in Table 1.

[0148] [Comparative Example 2]

[0149] A cyclic olefin resin film (manufactured by Zeon Corporation, Japan, trade name "zeonor") with a birefringence Δnxy of 0.021 was used. The preheating temperature was set to 150°C, and the stretching temperature was set to 148°C. Otherwise, the procedure was the same as in Example 1 to obtain a phase retardation film. The obtained phase retardation film had an orientation degree of 30.1%, an in-plane phase difference Re(550) of 140 nm, and a humidification phase difference change rate of 1.2%. Furthermore, an easy-to-bond layer was formed, and otherwise, the procedure was the same as in Example 1 to fabricate a polarizing plate with the obtained phase retardation film. The obtained phase retardation film and the polarizing plate with the phase retardation layer were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0150] [Comparative Example 3]

[0151] (Polymerization of polyester carbonate resins)

[0152] Polymerization was carried out using a batch polymerization unit consisting of two vertical reactors equipped with stirring blades and reflux coolers controlled at 100°C. The following components were added: 29.60 parts by mass (0.046 mol) of bis[9-(2-phenoxycarbonylethyl)fluorene-9-yl]methane, 29.21 parts by mass (0.200 mol) of isosorbide (ISB), 42.28 parts by mass (0.139 mol) of spirodiol (SPG), 63.77 parts by mass (0.298 mol) of diphenyl carbonate (DPC), and 1.19 × 10⁻⁶ mol of 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 is heated with a heat medium, and stirring begins when the internal temperature reaches 100°C. Forty minutes after the start of heating, the internal temperature is raised to 220°C and maintained at this temperature, while simultaneously reducing the pressure. After reaching 220°C, the pressure is set to 13.3 kPa for 90 minutes. Phenol vapor, a byproduct of the polymerization reaction, is introduced into a 100°C reflux cooler to return a certain amount of monomer components contained in the phenol vapor to the reactor. Uncondensed phenol vapor is introduced into a 45°C condenser for recovery. Nitrogen is introduced into the first reactor, and after temporarily restoring to atmospheric pressure, the oligomerized reaction liquid in the first reactor is transferred to the second reactor. Next, heating and depressurization are initiated in the second reactor, setting the internal temperature to 240°C and the pressure to 0.2 kPa for 50 minutes. Polymerization is then allowed to proceed until the specified stirring power is reached. Nitrogen gas was introduced into the reactor at the specified power level to restore pressure, and the generated polyester carbonate resin was extruded into water. The filament was then cut into granules. The birefringence Δnxy of the obtained polycarbonate resin was 0.012.

[0153] (Fabrication of phase retardation thin film)

[0154] After vacuum drying the obtained polyester carbonate resin (granules) at 100°C for 12 hours, a 130 μm thick elongated resin film was produced using a film forming apparatus equipped with a single-screw extruder (manufactured by Toshiba Machine Co., Ltd., barrel set temperature: 270°C), a T-die (width 1700 mm, set temperature: 270°C), a casting roll (set temperature: 75°C), and a winding machine. The obtained elongated resin film was stretched while being adjusted to obtain a specified phase difference, thereby obtaining a 40 μm thick phase difference film. Regarding the stretching conditions, the stretching ratio in the length direction was 2.12 times. The obtained phase difference film had an orientation degree of 28.8%, an in-plane phase difference Re(550) of 140 nm, and a humidification phase difference change rate of 3.1%. Furthermore, an easy-to-bond layer was provided, and otherwise operated in the same manner as in Example 1, a polarizing plate with a phase difference layer was fabricated using the obtained phase difference film. The obtained phase difference film and the polarizing plate with the phase difference layer were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0155] [Comparative Example 4]

[0156] A liquid crystal composition (coating solution) was prepared by dissolving 10 g of a polymerizable liquid crystal (manufactured by BASF: trade name "Paliocolor LC242", denoted by the following formula) exhibiting a nematic liquid crystal phase, and 3 g of a photopolymerization initiator for the polymerizable liquid crystal compound (manufactured by BASF: trade name "Irgacure 907") in 40 g of toluene. The birefringence Δnxy of the liquid crystal composition was 0.004.

[0157]

[0158] The above-mentioned liquid crystal coating solution was coated onto the surface of a polyethylene terephthalate (PET) film using a rod coater, and then heated and dried at 90°C for 2 minutes to form a liquid crystal layer. The formed liquid crystal layer was then irradiated with a metal halide lamp at 1 mJ / cm². 2 Light is used to cure the liquid crystal layer, thereby forming a liquid crystal cured layer on the PET film. The liquid crystal cured layer is peeled off from the PET film to obtain a phase retardation film. The obtained phase retardation film has an in-plane phase difference Re(550) of 140 nm, a humidification phase difference change rate of 2%, and a thickness of 2 μm. Furthermore, using the obtained phase retardation film in the same manner as in Example 1, a polarizing plate with a phase retardation layer is obtained. The obtained phase retardation film and the polarizing plate with the phase retardation layer are subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0159] Table 1

[0160]

[0161] As clearly shown in Table 1, the phase retardation film of the embodiments of the present invention exhibits excellent performance in terms of humidification phase difference change rate, weather resistance, and adhesion. This is presumably achieved by stretching the resin film containing a specific polycarbonate resin under specific stretching conditions. Furthermore, it can be seen that in the evaluation of humidification phase difference change, the phase retardation film without an easy-to-adhere layer suppresses humidification phase difference change compared to the phase retardation film with an easy-to-adhere layer (comparison of Example 1 and Comparative Example 1). Furthermore, a comparison of Examples 1-4 with Comparative Example 4 shows that by using a phase retardation film without an ultraviolet absorber, hue change in the weather resistance test can be suppressed.

[0162] Industrial availability

[0163] The phase retardation film and polarizing plate with phase retardation layer of the present invention are suitable for use in image display devices.

Claims

1. A polarizing plate with a phase retardation layer, comprising: a polarizing element, and a phase retardation film directly bonded to at least one side of the polarizing element by means of an adhesive layer. The phase retardation film is a phase retardation film composed of a resin with a birefringence Δnxy of 0.015 or higher, an orientation degree of 30% or higher, a front-side phase retardation Re(550) of 100nm~180nm or 220nm~340nm, and a phase retardation change rate of less than 1.5% after being maintained at 65℃ and 90%RH for 500 hours. The change rate of the b-value in the UV weathering test is less than 1%. A compatibility layer is formed between the phase difference film and the adhesive layer. The polarizing plate with the phase retardation layer does not have an easy-to-adhere layer. The adhesive layer is composed of an active energy radiation-cured adhesive composition. The active energy ray-cured adhesive composition comprises an active energy ray-cured compound. The Re(550) is the in-plane phase difference measured at 23°C using light with a wavelength of 550 nm.

2. The polarizing plate with a phase retardation layer according to claim 1, wherein, The resin comprises a polycarbonate-based resin.

3. The polarizing plate with a phase retardation layer according to claim 2, wherein, The polycarbonate resin contains structural units derived from the dihydroxy compound shown in formula (4) below. 。 4. The polarizing plate with a phase retardation layer according to claim 3, wherein, The polycarbonate resin further comprises structural units derived from alicyclic dihydroxy compounds, which are represented by the following general formula (II), R 1 For the structure shown in (IIb) below, n = 0, HOCH2-R 1 -CH2OH (II) 。 5. The polarizing plate with a phase retardation layer according to any one of claims 1 to 4, wherein the thickness of the phase retardation film is 10 μm to 50 μm.

6. A method for manufacturing a polarizing plate with a phase retardation layer, which is the method for manufacturing a polarizing plate with a phase retardation layer according to any one of claims 1 to 5, comprising the step of stretching a resin film formed from the resin to produce a phase retardation film.

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