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

Abstract

To provide a retardation film with suppressed variation in retardation in a humidification reliability test, suppressed variation in hue in a UV weather resistance test, and superior adhesiveness, and to provide a polarizing plate with a retardation layer comprising the same.SOLUTION: The optical film is made of a resin having a birefringence Δnxy of 0.015 or greater, has an orientation degree of 30% or greater and an in-plane retardation Re (550) in a range of 100-180 nm or 220-340 nm, and exhibits a phase difference change rate of 1.5% or less after being held at 65°C, 90%RH for 500 hours, and variation in b value of 1% or less in a UV weather resistance test. The resin includes a polycarbonate-based resin.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a retardation film, a polarizing plate with a retardation layer, and a method for manufacturing a retardation film.

Background Art

[0002] In recent years' display market, there is a need to reduce the display brightness in order to increase the battery life and further suppress heat generation. For this reason, as a polarizing plate used for a display, a polarizing plate with high light transmittance is required. However, when such a polarizing plate with high light transmittance is used for a display, there is a problem that the appearance deteriorates under humid conditions.

[0003] Furthermore, in recent years, displays are increasingly used in environments exposed to ultraviolet rays (for example, PID (Public Information Display), mobile phones). In particular, in a polarizing plate in which a retardation film is disposed on the panel side, there is a problem that the hue of the retardation film changes due to ultraviolet light, deteriorating the quality of the display.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present invention has been made to solve the above-mentioned conventional problems, and an object thereof is to provide a retardation film in which a change in retardation in a humidity reliability test is suppressed, a change in hue in a weather resistance test in the ultraviolet region is suppressed, and which has excellent adhesiveness, and a polarizing plate with a retardation layer including the retardation film.

Means for Solving the Problems

[0006] The retardation film in the embodiment of the present invention is composed of a resin having a birefringence Δnxy of 0.015 or more, an orientation degree of 30% or more, a front retardation Re(550) of 100 nm to 180 nm or 220 nm to 340 nm, a retardation change rate of 1.5% or less after being held at 65 °C and 90% RH for 500 hours, and a change rate of the b value in the weather resistance test in the ultraviolet region of 1% or less. In one embodiment, the resin includes a polycarbonate resin. In one embodiment, the polycarbonate resin includes a structural unit derived from a dihydroxy compound represented by the following formula (4).

Chemical formula

Chemical formula

Advantages of the Invention

[0007] According to an embodiment of the present invention, by stretching a resin film composed of a predetermined resin having a birefringence Δnxy of 0.015 or more, the degree of orientation becomes a certain value or more. As a result, a retardation film can be realized in which the change in retardation in the humidification reliability test is suppressed and the change in hue in the weather resistance test in the ultraviolet region is suppressed.

Embodiments for Carrying Out the Invention

[0008] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to these embodiments.

[0009] (Definition of Terms and Symbols) The definitions of the terms and symbols in this specification are as follows. (1) Refractive Index (nx, ny, nz) “nx” is the refractive index in the direction in which the in-plane refractive index is maximum (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. (2) In-Plane Retardation (Re) “Re(λ)” is the in-plane retardation measured with light of wavelength λ nm at 23°C. For example, “Re(550)” is the in-plane retardation measured with light of wavelength 550 nm at 23°C. Re(λ) is obtained by the formula: Re(λ)=(nx - ny)×d, where d (nm) is the thickness of the layer (film). (3) Birefringence (Δnxy) The birefringence Δnxy is obtained by the formula: Δnxy = nx - ny.

[0010] A. Retardation Film The retardation film according to an embodiment of the present invention contains a polycarbonate resin. Therefore, the retardation film according to an embodiment of the present invention is typically a stretched film of a polycarbonate resin film. Further, the retardation film according to an embodiment of the present invention preferably does not contain an ultraviolet absorber. Since the retardation film does not contain an ultraviolet absorber, it is possible to maintain a neutral hue when applied to an image display device.

[0011] The birefringence Δnxy of the resin constituting the retardation film is typically 0.015 or more, preferably 0.018 or more. The upper limit of the birefringence Δnxy of the resin can be, for example, 0.040. By stretching a resin having such birefringence Δnxy, a retardation film in which the retardation change under humid conditions is suppressed can be obtained.

[0012] The retardation film has an orientation degree of 30% or more, preferably 31% or more, and more preferably 32% or more. The upper limit of the orientation degree is, for example, 70%. If the orientation degree of the retardation film is within such a range, the adhesiveness of the retardation film becomes good. Such a range of the orientation degree can be realized by stretching the resin film. The orientation degree is measured, for example, by the X-ray diffraction method (XRD).

[0013] The in-plane retardation Re(550) of the retardation film is 100 nm to 180 nm or 220 nm to 340 nm, preferably 120 nm to 160 nm or 240 nm to 320 nm. That is, the retardation film can function as a λ / 2 retardation plate or a λ / 4 retardation plate.

[0014] The retardation change of the retardation film after being stored for 500 hours (humidification test) under the conditions of a temperature of 65° C. and a humidity of 90% is preferably 1.5% or less, and more preferably 1.4% or less. The lower limit can be, for example, 0.01%. The retardation change (%) is represented by |(Re 500 -Re0) / Re0|×100 (%). Re0 is the in-plane retardation (nm) of the retardation film before the start of the test, and Re500 is the in-plane retardation (nm) of the retardation film after the test. If the retardation change of the retardation film is within such a range, when the retardation film is applied to an image display device, the hue change due to the retardation at each location on the image display device becomes small, and the advantage of suppressing the occurrence of color unevenness in the display can be obtained.

[0015] In the above retardation film, the change in the b value is suppressed in the weather resistance test in the ultraviolet region. The change rate of the b value is 1% or less, preferably 0.95% or less. The lower limit of the change rate of the b value is, for example, 0%. That is, the retardation film can be favorably used even in applications where weather resistance is required. By including a specific polycarbonate resin described later, such an advantage can be obtained.

[0016] The thickness of the above retardation film is preferably 10 μm to 50 μm, more preferably 20 μm to 40 μm.

[0017] The moisture permeability of the above retardation film is preferably 250 g / m 2 ·24 h or less, more preferably 150 g / m 2 ·24 h or less. The lower limit can be, for example, 1 g / m 2 ·24 h. If the moisture permeability of the retardation film is within such a range, the advantage of suppressing the change in retardation in a humid environment can be obtained.

[0018] In the above retardation film, the absolute value of the photoelastic coefficient is preferably 2×10 -11 m 2 / N or less, more preferably 2.0×10 -13 m 2 / N to 1.5×10 -11 m 2 / N, still more preferably 1.0×10 -12 m 2 / N to 1.2×10 -11 m 2 / N. If the absolute value of the photoelastic coefficient is within such a range, when shrinkage stress occurs during heating, a change in the phase difference is less likely to occur. As a result, thermal non-uniformity of the obtained image display device can be preferably prevented.

[0019] According to an embodiment of the present invention, as described above, by stretching a resin film composed of a resin having a birefringence Δnxy in a specific range, a retardation film having an orientation degree in a specific range can be obtained. The retardation film satisfies a desired in-plane retardation, and further, a change in the phase difference in a humidity reliability test is suppressed, a change in hue in a weather resistance test in the ultraviolet region is suppressed, and it has excellent adhesiveness. Such a retardation film can be preferably used, for example, in a PID (Public Information Display) or a mobile phone.

[0020] B. Constituent Materials As described above, the retardation film is typically a stretched resin film of a polycarbonate resin.

[0021] (Polycarbonate Resin) The polycarbonate resin according to the present invention contains at least a structural unit derived from a dihydroxy compound having a bonding structure represented by the following structural formula (1), and at least a dihydroxy compound containing at least one bonding structure -CH2-O- in the molecule and a carbonic acid diester are reacted in the presence of a polymerization catalyst to produce it.

Chemical Formula

[0022] Here, as the dihydroxy compound having the bonding structure represented by the structural formula (1), any compound having two alcoholic hydroxyl groups and including a structure having a linking group -CH2-O- in the molecule and capable of reacting with a diester carbonate in the presence of a polymerization catalyst to produce a polycarbonate can be used, and a plurality of types can be used in combination. Further, as the dihydroxy compound used in the polycarbonate resin according to the present invention, a dihydroxy compound having no bonding structure represented by the structural formula (1) may be used in combination. Hereinafter, the dihydroxy compound having the bonding structure represented by the structural formula (1) may be abbreviated as dihydroxy compound (A), and the dihydroxy compound having no bonding structure represented by the structural formula (1) may be abbreviated as dihydroxy compound (B).

[0023] (Dihydroxy compound (A)) The "linking group -CH2-O-" in the dihydroxy compound (A) means a structure that binds to an atom other than a hydrogen atom to form a molecule. In this linking group, as the atom to which at least an oxygen atom can bind or the atom to which an oxygen atom and a carbon atom can bind simultaneously, a carbon atom is most preferable. The number of "linking group -CH2-O-" in the dihydroxy compound (A) is preferably 1 or more, more preferably 2 to 4.

[0024] More specifically, examples of the dihydroxy compound (A) include compounds having an aromatic group in the side chain and an ether group bonded to the aromatic group in the main chain, such as 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, 9,9-bis(4-(2-hydroxyethoxy)-3-tert-butyl-6-methylphenyl)fluorene, 9,9-bis(4-(3-hydroxy-2,2-dimethylpropoxy)phenyl)fluorene; 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,Bis(hydroxyalkoxyaryl)alkanes such as 2-bis[3-tert-butyl-4-(2-hydroxyethoxy)phenyl]propane, 2,2-bis[4-(2-hydroxyethoxy)phenyl]butane, 2,2-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, 2,2-bis[3-cyclohexyl-4-(2-hydroxyethoxy)phenyl]propane; bis(hydroxyalkoxyaryl)cycloalkanes such as 1,1-bis[4-(2-hydroxyethoxy)phenyl]cyclohexane, 1,1-bis[3-cyclohexyl-4-(2-hydroxyethoxy)phenyl]cyclohexane, 1,1-bis[4-(2-hydroxyethoxy)phenyl]cyclopentane; dihydroxyalkoxydiaryl ethers such as 4,4'-bis(2-hydroxyethoxy)diphenyl ether, 4,4'-bis(2-hydroxyethoxy)-3,3'-dimethyldiphenyl ether; bis(hydroxyalkoxyaryl)sulfides such as 4,4'-bis(2-hydroxyethoxyphenyl)sulfide, 4,4'-bis[4-(2-dihydroxyethoxy)-3-methylphenyl]sulfide; bis(hydroxyalkoxyaryl)sulfoxides such as 4,4'-bis(2-hydroxyethoxyphenyl)sulfoxide, 4,4'-bis[4-(2-dihydroxyethoxy)-3-methylphenyl]sulfoxide; bis(hydroxyalkoxyaryl)sulfones such as 4,4'-bis(2-hydroxyethoxyphenyl)sulfone, 4,4'-bis[4-(2-dihydroxyethoxy)-3-methylphenyl]sulfone; 1,4-bis(hydroxyethoxy)benzene, 1,3-bis(hydroxyethoxy)benzene, 1,2-bis(hydroxyethoxy)benzene, 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, sugar alcohols typified by the dihydroxy compound represented by the following formula (4), and compounds having a cyclic ether structure such as spiro glycol represented by the following general formula (6) can be mentioned. These may be used alone or in combination of two or more kinds.

[0025]

Chemical formula

[0026] These dihydroxy compounds (A) may be used alone or in combination of two or more kinds. In the present invention, examples of the dihydroxy compound represented by the formula (4) include isosorbide, isomannide, and isoidide, which are in a stereoisomeric relationship. These may be used alone or in combination of two or more kinds.

[0027] Among the dihydroxy compounds (A), isosorbide obtained by dehydrative condensation of sorbitol, which is abundantly present as a resource and easily available and is produced from various starches, is most preferable in terms of availability, ease of production, optical properties, and moldability. In the present invention, isosorbide is preferably used as the dihydroxy compound (A).

[0028] (Dihydroxy compound (B)) In the present invention, a dihydroxy compound (B), which is a dihydroxy compound other than the dihydroxy compound (A), may be used as the dihydroxy compound. Examples of the dihydroxy compound (B) include alicyclic dihydroxy compounds, aliphatic dihydroxy compounds, oxyalkylene glycols, aromatic dihydroxy compounds, and diols having a cyclic ether structure. These can be used together with the dihydroxy compound (A), for example, the dihydroxy compound represented by the formula (4), as a dihydroxy compound that becomes a constituent unit of the polycarbonate.

[0029] The alicyclic dihydroxy compounds that can be used in the present invention are not particularly limited, but preferably, compounds containing a 5-membered ring structure or a 6-membered ring structure are used. Further, the 6-membered ring structure may be fixed in a chair form or a boat form by a covalent bond. Since the alicyclic dihydroxy compound has a 5-membered ring or 6-membered ring structure, the heat resistance of the resulting polycarbonate can be increased. The number of carbon atoms contained in the alicyclic dihydroxy compound is usually 70 or less, preferably 50 or less, more preferably 30 or less. As this value increases, the heat resistance increases, but the synthesis becomes difficult, the purification becomes difficult, or the cost becomes high. The smaller the number of carbon atoms, the easier it is to purify and obtain.

[0030] Specific examples of the alicyclic dihydroxy compound containing a 5-membered ring structure or a 6-membered ring structure that can be used in the present invention include alicyclic dihydroxy compounds represented by the following general formula (II) or (III). HOCH2-R 1 -CH2OH (II) HO-R 2 -OH (III) (In the formulas (II) and (III), R 1 , R 2 each represents a cycloalkylene group having 4 to 20 carbon atoms.) As cyclohexanedimethanol, which is an alicyclic dihydroxy compound represented by the above general formula (II), in the general formula (II), R 1 includes various isomers represented by the following general formula (IIa) (wherein R 3 represents an alkyl group having 1 to 12 carbon atoms or a hydrogen atom). Specific examples of such compounds include 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, and the like.

[0031]

Chemical formula

[0032] As the alicyclic dihydroxy compound represented by the general formula (II), tricyclodecane dimethanol and pentacyclopentadecane dimethanol, in the general formula (II), R 1 includes various isomers represented by the following general formula (IIb) (wherein n represents 0 or 1).

[0033]

Chemical formula

[0034] As the alicyclic dihydroxy compound represented by the general formula (II), decalin dimethanol or tricyclotetradecane dimethanol, in the general formula (II), R 1 includes various isomers represented by the following general formula (IIc) (wherein m represents 0 or 1). Specific examples of such compounds include 2,6-decalin dimethanol, 1,5-decalin dimethanol, 2,3-decalin dimethanol, and the like.

[0035]

Chemical formula

[0036] Further, as the alicyclic dihydroxy compound represented by the general formula (II), norbornane dimethanol, in the general formula (II), R 1 includes various isomers represented by the following general formula (IId). Specific examples of such compounds include 2,3-norbornane dimethanol, 2,5-norbornane dimethanol, and the like.

[0037]

Chemical formula

[0038] As the alicyclic dihydroxy compound represented by the general formula (II), adamantane dimethanol, in the general formula (II), R 1includes various isomers represented by the following general formula (IIe). Specific examples of such compounds include 1,3-adamantanediol.

[0039] [Chemical formula]

[0040] In addition, cyclohexanediol, an alicyclic dihydroxy compound represented by the above general formula (III), in the general formula (III), R 2 includes various isomers represented by the following general formula (IIIa) (wherein R 3 represents an alkyl group having 1 to 12 carbon atoms or a hydrogen atom). Specific examples of such compounds include 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 2-methyl-1,4-cyclohexanediol, and the like.

[0041] [Chemical formula]

[0042] As tricyclodecanediol and pentacyclopentadecanediol, which are alicyclic dihydroxy compounds represented by the above general formula (III), in the general formula (III), R 2 includes various isomers represented by the following general formula (IIIb) (wherein n represents 0 or 1).

[0043] [Chemical formula]

[0044] As decahydroxybenzene diol or tricyclotetradecane diol, which are alicyclic dihydroxy compounds represented by the above general formula (III), in the general formula (III), R 2includes various isomers represented by the following general formula (IIIc) (wherein m represents 0 or 1). Specifically, 2,6-decalindiol, 1,5-decalindiol, 2,3-decalindiol, etc. are used.

[0045]

Chemical formula

[0046] As the norbornanediol which is an alicyclic dihydroxy compound represented by the above general formula (III), in the general formula (III), R 2 includes various isomers represented by the following general formula (IIId). Specifically, 2,3-norbornanediol, 2,5-norbornanediol, etc. are used.

[0047]

Chemical formula

[0048] As the adamantanediol which is an alicyclic dihydroxy compound represented by the above general formula (III), in the general formula (III), R 2 includes various isomers represented by the following general formula (IIIe). Specifically, 1,3-adamantanediol, etc. are used.

[0049]

Chemical formula

[0050] Among the specific examples of the above-mentioned alicyclic dihydroxy compounds, cyclohexanedimethanols, tricyclodecane dimethanols, adamantanediols, and pentacyclopentadecane dimethanols are particularly preferred. From the viewpoints of easy availability and easy handling, 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,2-cyclohexanedimethanol, and tricyclodecane dimethanol are preferred. In the present invention, tricyclodecane dimethanol is preferably used as the dihydroxy compound (B).

[0051] Examples of the aliphatic dihydroxy compounds that can be used in the present 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 the oxyalkylene glycols that can be used in the present invention include diethylene glycol, triethylene glycol, tetraethylene glycol, and polyethylene glycol.

[0052] Examples of the aromatic dihydroxy compounds that can be used in the present invention include 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, 1,1-bis(4-hydroxyphenyl)ethane, 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'-dihydroxydiphenylether, 4,4'-dihydroxy-3,3'-dichlorodiphenylether, 4,4'-dihydroxy-2,5-diethoxydiphenylether, 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.

[0053] Examples of the diols having a cyclic ether structure that can be used in the present invention include spiroglycols and dioxane glycols. The above-exemplified compounds are examples of the alicyclic dihydroxy compounds, aliphatic dihydroxy compounds, oxyalkylene glycols, aromatic dihydroxy compounds, and diols having a cyclic ether structure that can be used in the present invention, and are not limited thereto. These compounds can be used alone or in combination of two or more with the dihydroxy compound represented by the formula (4).

[0054] By using these dihydroxy compounds (B), effects such as improvement in flexibility according to the use, improvement in heat resistance, and improvement in moldability can be obtained. The ratio of the dihydroxy compound (A), for example, the dihydroxy compound represented by the formula (4), to all the dihydroxy compounds constituting the polycarbonate resin according to the present invention is not particularly limited, but is preferably 10 mol% or more, more preferably 40 mol% or more, still more preferably 60 mol% or more, preferably 90 mol% or less, more preferably 80 mol% or less, and still more preferably 70 mol% or less. If the content ratio of the structural units derived from other dihydroxy compounds is too high, the performance such as optical properties may be deteriorated.

[0055] Among the above other dihydroxy compounds, when an alicyclic dihydroxy compound is used, the total ratio of the dihydroxy compound (A), for example, the dihydroxy compound represented by the formula (4), and the alicyclic dihydroxy compound to all the dihydroxy compounds constituting the polycarbonate is not particularly limited, but is preferably 80 mol% or more, more preferably 90 mol% or more, and still more preferably 95 mol% or more.

[0056] In addition, regarding the content ratio of the structural unit derived from the dihydroxy compound (A), for example, the dihydroxy compound represented by the formula (4), and the structural unit derived from the alicyclic dihydroxy compound in the polycarbonate resin according to the present invention, it can be selected at any ratio, but the structural unit derived from the dihydroxy compound represented by the formula (4): the structural unit derived from the alicyclic dihydroxy compound = 1:99 to 99:1 (mol%) is preferable, and particularly the structural unit derived from the dihydroxy compound represented by the formula (4): the structural unit derived from the alicyclic dihydroxy compound = 10:90 to 90:10 (mol%) is preferable. If the structural unit derived from the dihydroxy compound represented by the formula (4) is more and the structural unit derived from the alicyclic dihydroxy compound is less than the above range, it is likely to be colored, and conversely, if the structural unit derived from the dihydroxy compound represented by the formula (4) is less and the structural unit derived from the alicyclic dihydroxy compound is more, the molecular weight tends to be difficult to increase.

[0057] Furthermore, when using aliphatic dihydroxy compounds, oxyalkylene glycols, aromatic dihydroxy compounds, and diols having a cyclic ether structure, the ratio of the dihydroxy compound (A), for example, the dihydroxy compound represented by the formula (4), to all the dihydroxy compounds constituting the polycarbonate is not particularly limited and can be selected at any ratio. Also, the content ratio of the structural unit derived from the dihydroxy compound (A), for example, the dihydroxy compound represented by the formula (4), to the structural units derived from these respective dihydroxy compounds is not particularly limited and can be selected at any ratio.

[0058] Details of the polycarbonate resin are described, for example, in JP-A-2012-31370 (Patent No. 5448264). The description of the patent document is incorporated herein by reference.

[0059] C. Method for manufacturing a retardation film The method for manufacturing a retardation film according to an embodiment of the present invention includes subjecting a resin film to a stretching treatment. The resin film is a film formed from the polycarbonate resin described in the above item B.

[0060] In one embodiment, the retardation film is produced by uniaxially stretching or fixed-end uniaxially stretching the resin film. Specific examples of fixed-end uniaxial stretching include a method of stretching the resin film in the width direction (lateral direction) while running it in the longitudinal direction. The stretching ratio is preferably 1.1 times to 3.5 times, more preferably 1.5 times to 3.0 times, and even more preferably 2.0 times to 2.5 times. By stretching the resin film formed from the polycarbonate resin described in item B at such a stretching ratio, the solvent permeability into the retardation film changes, a compatible layer with the adhesive layer is formed, and the adhesive strength is improved. This phenomenon is more prominent as the retardation value of the retardation film is higher. That is, by stretching a specific polycarbonate resin at the above-described stretching ratio, the change in retardation under humid conditions of the retardation film can be significantly suppressed.

[0061] The stretching temperature of the resin film is preferably Tg - 30°C to Tg + 30°C, more preferably Tg - 15°C to Tg + 15°C, and even more preferably Tg - 10°C to Tg + 10°C. By stretching at such a temperature, a retardation film having appropriate characteristics in the present invention can be obtained. Note that Tg is the glass transition temperature of the constituent material of the film.

[0062] D. Polarizing plate with a retardation layer The retardation film described in the above items A to C can be provided as a laminate with other optical films and / or optical members. In one embodiment, the retardation film can be provided as a laminate with a polarizing plate (polarizing plate with a retardation layer). Therefore, the present invention includes a polarizing plate with a retardation layer having the above retardation film. The polarizing plate with a retardation layer according to an embodiment of the present invention includes a polarizing plate and a retardation layer composed of the above retardation film. In the retardation film, the angle formed by the absorption axis of the polarizer of the polarizing plate and the slow axis of the retardation film can be appropriately set according to the use and purpose. In one embodiment, the angle is preferably 40° to 50°, more preferably 42° to 48°, and even more preferably about 45°.

[0063] The polarizing plate with a retardation layer typically has a polarizer and the above retardation film bonded to at least one side of the polarizer via an adhesive layer. As described above, the retardation film has excellent adhesiveness to the polarizer.

[0064] Typical examples of the adhesive composition constituting the adhesive layer include an active energy ray curable adhesive composition. The active energy ray curable adhesive composition contains an active energy ray curable compound.

[0065] The active energy ray curable adhesive composition according to the present invention is, for example, an active energy ray curable adhesive composition containing active energy ray curable compounds (A), (B), and (C) as curable components. When the total amount of the composition is 100% by weight, the SP value is 29.0 (MJ / m 3 ) 1 / 232.0 (MJ / m 3 ) 1 / 2 or less of the active energy ray-curable compound (A) in an amount of 0.0 to 4.0% by weight, and the SP value is 18.0 (MJ / m 3 ) 1 / 2 or more and 21.0 (MJ / m 3 ) 1 / 2 less than the active energy ray-curable compound (B) in an amount of 5.0 to 98.0% by weight, and the SP value is 21.0 (MJ / m 3 ) 1 / 2 or more and 26.0 (MJ / m 3 ) 1 / 2 or less of the active energy ray-curable compound (C) in an amount of 5.0 to 98.0% by weight. In the present invention, the "total amount of the composition" means the total amount including various initiators and additives in addition to the active energy ray-curable compound.

[0066] The active energy ray-curable compound (A) has a radically polymerizable group such as a (meth) acrylate group and an SP value of 29.0 (MJ / m 3 ) 1 / 2 or more and 32.0 (MJ / m 3 ) 1 / 2 or less, and any compound can be used without limitation. Specific examples of the active energy ray-curable compound (A) include, for example, hydroxyethyl acrylamide (SP value 29.5), N-methylol acrylamide (SP value 31.5), and the like. In the present invention, the (meth) acrylate group means an acrylate group and / or a methacrylate group.

[0067] The active energy ray-curable compound (B) has a radically polymerizable group such as a (meth) acrylate group and an SP value of 18.0 (MJ / m 3 ) 1 / 2 or more and 21.0 (MJ / m 3 ) 1 / 2Compounds with a value less than this can be used without limitation. Specific examples of the active energy ray-curable compound (B) include, for example, tripropylene glycol diacrylate (SP value 19.0), 1,9-nonanediol diacrylate (SP value 19.2), tricyclodecane dimethanol diacrylate (SP value 20.3), cyclic trimethylolpropane formal acrylate (SP value 19.1), dioxane glycol diacrylate (SP value 19.4), EO-modified diglycerin tetraacrylate (SP value 20.9), and the like. Note that commercially available products can also be suitably used as the active energy ray-curable compound (B). For example, Aronix M-220 (manufactured by Toagosei 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, SP value 19.1), CD-536 (manufactured by Sartomer, SP value 19.4), and the like.

[0068] The active energy ray-curable compound (C) has a radically polymerizable group such as a (meth)acrylate group and an SP value of 21.0 (MJ / m 3 ) 1 / 2 or more and 26.0 (MJ / m 3 ) 1 / 2 or less. Compounds with a value within this range can be used without limitation. Specific examples of the active energy ray-curable compound (C) include, for example, acryloylmorpholine (SP value 22.9), N-methoxymethylacrylamide (SP value 22.9), N-ethoxymethylacrylamide (SP value 22.3), and the like. Note that commercially available products can also be suitably used as the active energy ray-curable compound (C). For example, ACMO (manufactured by Kogyo Shokai Co., Ltd., SP value 22.9), Wasmer 2MA (manufactured by Kasano Kogyo Co., Ltd., SP value 22.9), Wasmer EMA (manufactured by Kasano Kogyo Co., Ltd., SP value 22.3), Wasmer 3MA (manufactured by Kasano Kogyo Co., Ltd., SP value 22.4), and the like.

[0069] Details of the adhesive composition are described, for example, in Japanese Patent Application Laid-Open No. 2019-147865. The description of the patent document is incorporated herein by reference. By combining the adhesive layer and the retardation film, a compatible layer is formed between the retardation film and the adhesive layer, and the adhesiveness of the retardation film is improved. Therefore, in the production of the polarizing plate with a retardation layer, it is not necessary to provide an easy-adhesion layer between the retardation film and the adhesive layer. Therefore, in the polarizing plate with a retardation layer, preferably, the retardation film is directly bonded via an adhesive layer to at least one side of the polarizer. Such a polarizing plate with a retardation layer having no easy-adhesive layer can suppress a change in retardation under humid conditions well.

[0070] At least one side of the polarizer may have a protective layer. Further, the surface of the polarizing plate with a retardation layer opposite to the viewing side may have an adhesive layer and a separator. Since the configurations of the polarizer, the protective layer, the adhesive layer, and the separator are well-known in the industry, detailed descriptions thereof are omitted.

Examples

[0071] Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples. The measurement methods and evaluation methods for each property are as follows. (1) In-plane retardation The retardation films obtained in the examples and comparative examples were cut out into a length of 4 cm and a width of 4 cm to obtain measurement samples. For the measurement samples, the in-plane retardation Re(550) was measured using a product named "Axoscan" manufactured by Axometrics. (2) Refractive index and birefringence Δnxy Measurement was performed using an Abbe refractometer (DR-M2, manufactured by Atago Co., Ltd.). The measurement was performed in an environment at 23°C. (3) Thickness For a thickness of 10 μm or less, measurement was performed using an interference film thickness meter (manufactured by Otsuka Electronics Co., Ltd., product name "MCPD-9800"). For a thickness exceeding 10 μm, measurement was performed using a digital micrometer (manufactured by Anritsu Corporation, product name "KC-351C"). (4) Degree of orientation Using the retardation films obtained in the examples and comparative examples, the degree of orientation was determined by X-ray diffraction method (XRD). (5) Humidification retardation change The retardation film-attached polarizing plates obtained in the examples and comparative examples were cut into 5 cm × 5 cm pieces, an adhesive was applied to one side with a hand roller, and the adhesive side was attached to one side of an alkali glass to obtain test pieces. The test pieces were stored in an oven at a temperature of 65°C and a humidity of 90% for 500 hours (humidification test), and the retardation change (%) before and after the test was calculated. Those with a retardation change of 1.5% or less were considered good, and those exceeding 1.5% were considered defective. (6) Parallel hue a value and b value The parallel hue a value and parallel hue b value of the retardation films obtained in the examples and comparative examples were determined. The measurement was performed using a spectro-ellipsometer (manufactured by JASCO Corporation, product name "V-7100"). Those with a change rate of 1% or less between the b value before being put into an ultraviolet fade tester (equipment name; ultraviolet fade meter tester U48, manufactured by Suga Test Instruments Co., Ltd.) and the b value after 100 h of input were considered good, and those exceeding 1% were considered defective. (7) Adhesion The retardation film and the polarizer obtained in the examples and comparative examples were bonded together to obtain a laminate. The obtained laminate was cut into a size of 200 mm parallel to the stretching direction of the polarizer and 15 mm perpendicular to it, and the laminate was bonded to a glass plate. Then, a cut was made with a cutter knife between the retardation film and the polarizer, and the retardation film and the polarizer were peeled at a peeling speed of 1000 mm / min in the 90-degree direction using a tensilon universal testing machine RTC (manufactured by A&D Company, Limited), and the peeling strength (N / 15 mm) was measured. When the peeling strength was 1 N / 15 mm or more, it was considered good, and when it was less than 1 N / 15 mm, it was considered defective.

[0072] [Example 1] 1. Production of resin film To 81.98 parts by mass of isosorbide (hereinafter sometimes abbreviated as "ISB"), 47.19 parts by mass of tricyclodecane dimethanol (hereinafter sometimes abbreviated as "TCDDM"), 175.1 parts by mass of diphenyl carbonate (hereinafter sometimes abbreviated as "DPC"), and as a catalyst, 0.979 part by mass of a 0.2 mass% aqueous solution of cesium carbonate were charged into a reaction vessel. As the first stage of the reaction under a nitrogen atmosphere, the temperature of the heating bath was heated to 150°C, and the raw materials were dissolved (about 15 minutes) while stirring as necessary. Next, the pressure was changed from normal pressure to 13.3 kPa, and while raising the temperature of the heating bath to 190°C over 1 hour, the generated phenol was withdrawn outside the reaction vessel. After holding the entire reaction vessel at 190°C for 15 minutes, as the second stage of the process, the pressure inside the reaction vessel was set to 6.67 kPa, the temperature of the heating bath was raised to 230°C in 15 minutes, and the generated phenol was withdrawn outside the reaction vessel. Since the stirring torque of the stirrer increased, the temperature was raised to 250°C in 8 minutes, and in order to further remove the generated phenol, the pressure inside the reaction vessel was brought to 0.200 kPa or less. After reaching a predetermined stirring torque, the reaction was terminated, and the generated reaction product was extruded into water to obtain pellets of a polycarbonate resin. 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 film-forming apparatus equipped with a single-screw extruder (manufactured by Toshiba Machine Co., Ltd., cylinder set temperature: 250°C), a T-die (width 1700 mm, set temperature: 250°C), a cast roll (set temperature: 60°C), and a winder was used to produce a polycarbonate resin film with a thickness of 90 μm.

[0073] Production of a retardation film The above-mentioned un-stretched polycarbonate resin film was subjected to pre-treatment and simultaneous biaxial stretching using a simultaneous biaxial stretching machine to obtain a retardation film. The pre-heating temperature was 140°C, the stretching temperature was 138°C, and the stretching ratio in the longitudinal direction was 2.4 times. The degree of orientation of the obtained retardation film was 31.1%, the in-plane retardation Re(550) was 140 nm, the humidity-induced retardation change rate was 1.21%, and the thickness was 40 μm. The obtained retardation film was subjected to the evaluations in (6) and (7) above. The results are shown in Table 1.

[0074] 3. Production of Polarizing Plate As the resin substrate, an amorphous isophthal copolymer polyethylene terephthalate film (thickness: 100 μm) in a long strip shape with a Tg of about 75°C was used, and one side of the resin substrate was subjected to corona treatment. 13 parts by weight of potassium iodide was added to 100 parts by weight of a PVA-based resin obtained by mixing polyvinyl alcohol (degree of polymerization 4200, degree of saponification 99.2 mol%) and acetoacetyl-modified PVA (manufactured by Nippon Gohsei Chemical Industry Co., Ltd., trade name "Gosefimer") at a ratio of 9:1, and the mixture was dissolved in water to prepare a PVA aqueous solution (coating solution). The above PVA aqueous solution was applied to the corona-treated surface of the resin substrate and dried at 60°C to form a PVA-based resin layer with a thickness of 13 μm, and a laminate was produced. The obtained laminate was uniaxially stretched 2.4 times in the longitudinal direction (length direction) in an oven at 130°C (air-assisted stretching treatment). Next, the laminate was immersed in an insolubilization bath at a liquid temperature of 40°C (an aqueous boric acid solution obtained by blending 4 parts by weight of boric acid with respect to 100 parts by weight of water) for 30 seconds (insolubilization treatment). Next, the laminate was immersed in a dyeing bath at a liquid temperature of 30°C (an aqueous iodine solution obtained by blending iodine and potassium iodide at a weight ratio of 1:7) for 60 seconds while adjusting the concentration so that the single transmittance (Ts) of the finally obtained polarizer becomes a desired value (dyeing treatment). Next, the laminate was immersed in a crosslinking bath at a liquid temperature of 40°C (an aqueous boric acid solution obtained by blending 3 parts by weight of potassium iodide and 5 parts by weight of boric acid with respect to 100 parts by weight of water) for 30 seconds (crosslinking treatment). Thereafter, while the laminate was immersed in an aqueous boric acid solution at a liquid temperature of 70°C (boric acid concentration 4 wt%, potassium iodide concentration 5 wt%), uniaxial stretching was performed in the longitudinal direction (length direction) between rolls with different peripheral speeds so that the total stretching ratio became 5.5 times (in-water stretching treatment). Thereafter, the laminate was immersed in a washing bath at a liquid temperature of 20°C (an aqueous solution obtained by blending 4 parts by weight of potassium iodide with respect to 100 parts by weight of water) (washing treatment). Thereafter, while drying in an oven maintained at about 90°C, it was brought into contact with a SUS heating roll whose surface temperature was maintained at about 75°C (drying shrinkage treatment). In this way, a polarizer with a thickness of about 5 μm was formed on the resin substrate, and a polarizing plate having a resin substrate / polarizer structure was obtained. Furthermore, on the surface of the obtained polarizer opposite to the resin substrate, as a protective layer, a cycloolefin-based film (manufactured by Nippon Zeon Co., Ltd., trade name "Zeonoa") was bonded via an ultraviolet-curable adhesive. Specifically, it was coated so that the total thickness of the curable adhesive became about 1.0 μm and bonded using a roll machine. Thereafter, UV light was irradiated from the cycloolefin-based film side to cure the adhesive. Next, the resin substrate was peeled off to obtain a polarizing plate having a cycloolefin-based film (protective layer) / polarizer structure. The in-plane retardation of the protective layer was 135 nm. The angle formed by the slow axis of the protective layer and the absorption axis of the polarizer was made substantially parallel.

[0075] 4. Production of Polarizing Plate with Retardation Layer On one side of the above-mentioned retardation film, using an MCD coater (manufactured by Fuji Machine Co., Ltd.), an active energy ray-curable adhesive composition was coated to a thickness of 0.7 μm and bonded to the polarizer surface of the above-mentioned polarizing plate using a roll machine. The active energy ray-curable adhesive composition was obtained by mixing 40 parts of "Light Acrylate 1.9ND-A" manufactured by Kyoeisha Chemical Co., Ltd., 20 parts of "Aronix M-5700" manufactured by Toagosei Co., Ltd., and 10 parts of "ARUFON UP1190" manufactured by Toagosei Co., Ltd. and stirring at 50°C for 1 hour. Thereafter, 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, and then dried with hot air at 70°C for 3 minutes to obtain a polarizing plate with a retardation layer. The angle formed by the absorption axis of the polarizer and the slow axis of the retardation film was set to 45°. The obtained polarizing plate with a retardation layer was subjected to the evaluation in the above (5). The results are shown in Table 1.

[0076] [Example 2] A retardation film was obtained in the same manner as in Example 1 except that the thickness was 30 μm. The degree of orientation of the obtained retardation film was 31.9%, the in-plane retardation Re(550) was 140 nm, and the humidity-induced retardation change rate was 1.15%. Further, in the same manner as in Example 1, a polarizing plate with a retardation layer was obtained using the obtained retardation film. The obtained retardation film and the polarizing plate with a retardation layer were subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0077] [Example 3] A retardation film was obtained in the same manner as in Example 1 except that the birefringence Δnxy of the polycarbonate resin was 0.018, the preheating temperature was 138°C, and the stretching temperature was 135°C. The degree of orientation of the obtained retardation film was 35.7%, the in-plane retardation Re(550) was 270 nm, and the humidity-induced retardation change rate was 1.29%. Further, in the same manner as in Example 1, a polarizing plate with a retardation layer was obtained using the obtained retardation film. The obtained retardation film and the polarizing plate with a retardation layer were subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0078] [Example 4] A retardation film was obtained in the same manner as in Example 1 except that the birefringence Δnxy of the polycarbonate resin was 0.024, the thickness was 30 μm, the stretching ratio was 2.5 times, the preheating temperature was 138°C, and the stretching temperature was 135°C. The degree of orientation of the obtained retardation film was 34.6%, the in-plane retardation Re(550) was 260 nm, and the humidity-induced retardation change rate was 1.31%. Further, in the same manner as in Example 1, a polarizing plate with a retardation layer was obtained using the obtained retardation film. The obtained retardation film and the polarizing plate with a retardation layer were subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0079] [Comparative Example 1] A retardation film was obtained in the same manner as in Example 1, except that the birefringence Δnxy of the polycarbonate resin was 0.016 and the draw ratio in the longitudinal direction was 2.12 times. The degree of orientation of the obtained retardation film was 29.4%, the in-plane retardation Re(550) was 140 nm, and the humidity-induced retardation change rate was 2.81%. Furthermore, a polarizing plate with a retardation layer was produced using the obtained retardation film in the same manner as in Example 1, except that an easy-adhesion layer was provided. The obtained retardation film and the polarizing plate with a retardation layer were subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0080] [Comparative Example 2] A retardation film was obtained in the same manner as in Example 1, except that a cycloolefin-based resin film (manufactured by Nippon Zeon Co., Ltd., trade name "Zeonor") with a birefringence Δnxy of 0.021 was used, the preheating temperature was 150 °C, and the drawing temperature was 148 °C. The degree of orientation of the obtained retardation film was 30.1%, the in-plane retardation Re(550) was 140 nm, and the humidity-induced retardation change rate was 1.2%. Furthermore, a polarizing plate with a retardation layer was produced using the obtained retardation film in the same manner as in Example 1, except that an easy-adhesion layer was provided. The obtained retardation film and the polarizing plate with a retardation layer were subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0081] [Comparative Example 3] [Polymerization of Polyester Carbonate Resin] Polymerization was carried out using a batch polymerization apparatus consisting of two vertical reactors equipped with stirring blades and a reflux condenser controlled at 100 °C. 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 spiroglycol (SPG), 63.77 parts by mass (0.298 mol) of diphenyl carbonate (DPC), and 1.19×10 -2 parts by mass (6.78×10 -5(0 mol) was charged. After replacing the inside of 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 up, the internal temperature reached 220 °C, and while controlling to maintain this temperature, reduced pressure was started and it was made 13.3 kPa in 90 minutes after reaching 220 °C. The phenol vapor by-produced along with the polymerization reaction was led to a reflux condenser at 100 °C, the monomer components contained in a small amount in the phenol vapor were returned to the reactor, and the phenol vapor that did not condense was led to a condenser at 45 °C and recovered. Nitrogen was introduced into the first reactor to once restore the pressure to atmospheric pressure, and then the oligomerized reaction solution in the first reactor was transferred to the second reactor. Next, heating up and reduced pressure in the second reactor were started, and the internal temperature was made 240 °C and the pressure 0.2 kPa in 50 minutes. Thereafter, the polymerization was allowed to proceed until a predetermined stirring power was reached. When the predetermined power was reached, nitrogen was introduced into the reactor to restore the pressure, and the produced polyester carbonate resin was extruded into water, and the strands were cut to obtain pellets. The birefringence Δnxy of the obtained polycarbonate resin was 0.012.

[0082] (Production of the retardation film) After vacuum-drying the obtained polyester carbonate resin (pellets) at 100 °C for 12 hours, using a film forming apparatus equipped with a single-screw extruder (manufactured by Toshiba Machine Co., Ltd., cylinder set temperature: 270 °C), a T-die (width 1700 mm, set temperature: 270 °C), a casting roll (set temperature: 75 °C) and a winder, a long resin film with a thickness of 130 μm was produced. The obtained long resin film was stretched while adjusting so as to obtain a predetermined retardation, and a retardation film with a thickness of 40 μm was obtained. The stretching conditions were a stretching ratio of 2.12 times in the longitudinal direction. The degree of orientation of the obtained retardation film was 28.8%, the in-plane retardation Re(550) was 140 nm, and the humidity-dependent retardation change rate was 3.1%. Further, a polarizing plate with a retardation layer was produced using the obtained retardation film in the same manner as in Example 1 except that an easy-adhesion layer was provided. The obtained retardation film and the polarizing plate with a retardation layer were subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0083] [Comparative Example 4] 10 g of a polymerizable liquid crystal exhibiting a nematic liquid crystal phase (manufactured by BASF: trade name "Paliocolor LC242", represented by the following formula) and 3 g of a photopolymerization initiator for the polymerizable liquid crystal compound (manufactured by BASF: trade name "Irgacure 907") were dissolved in 40 g of toluene to prepare a liquid crystal composition (coating solution). The birefringence Δnxy of the liquid crystal composition was 0.004.

Chemical formula

[0084]

Table 1

[0085] As is clear from Table 1, it can be seen that the retardation films of the examples of the present invention are excellent in all of the humidity-dependent retardation change rate, weather resistance, and adhesiveness. It is presumed that this is achieved by stretching a resin film containing a specific polycarbonate resin under specific stretching conditions. Furthermore, in the evaluation of the humidity-dependent retardation change, it can be seen that the retardation film without an easy-adhesion layer has a suppressed humidity-dependent retardation change compared to the retardation film with an easy-adhesion layer (comparison between Example 1 and Comparative Example 1). Furthermore, from the comparison between Examples 1 to 4 and Comparative Example 4, it can be seen that using a retardation film not containing an ultraviolet absorber suppresses the hue change in the weather resistance test.

Industrial Applicability

[0086] The retardation film and the polarizing plate with a retardation layer according to the embodiments of the present invention are suitably used in an image display device.

Claims

1. A polarizer and a retardation film directly bonded via an adhesive layer to one side of the polarizer, wherein the retardation film is a retardation film composed of a resin having a birefringence Δnxy of 0.015 or more, having an orientation degree of 30% or more, a front retardation Re(550) of 100 nm to 180 nm or 220 nm to 340 nm, a retardation change rate of 1.5% or less after being held at 65 °C and 90% RH for 500 hours, and a change rate of the b value in a weather resistance test in the ultraviolet region of 1% or less, wherein the resin includes a polycarbonate-based resin, wherein the polycarbonate-based resin includes at least a structural unit derived from a dihydroxy compound having a bonding structure represented by the following formula (1), 【Chemical 1】 wherein a compatible layer is provided between the retardation film and the adhesive layer, A polarizing plate with a retardation layer.

2. The polarizing plate with a retardation layer according to claim 1, wherein the polycarbonate-based resin includes a structural unit derived from a dihydroxy compound represented by the following formula (4). 【Chemical 2】

3. The polycarbonate resin further contains a structural unit derived from an alicyclic dihydroxy compound, and the alicyclic dihydroxy compound is represented by the following general formula (II), R １ is a structure represented by the following (IIb), and n = 0. The retardation layer-attached polarizing plate according to claim 2: HOCH ２ -R １ -CH ２ OH (II) [Chemical Formula 3]

4. The polarizing plate with a retardation layer according to any one of claims 1 to 3, wherein the thickness of the retardation film is 10 μm to 50 μm.

5. The polarizing plate with a retardation layer according to any one of claims 1 to 4, wherein the adhesive layer is composed of an active energy ray-curable adhesive composition.

6. The active energy ray-curable adhesive composition has an SP value of 29.0 (MJ / m ３ ) １／２ or more and 32.0 (MJ / m ３ ) １／２ or less, an active energy ray-curable compound (A), an active energy ray-curable compound (B) having an SP value of 18.0 (MJ / m ３ ) １／２ or more and less than 21.0 (MJ / m ３ ) １／２ and an active energy ray-curable compound (C) having an SP value of 21.0 (MJ / m ３ ) １／２ or more and 26.0 (MJ / m ３ ) １／２ or less. The polarizing plate with a retardation layer according to claim 5.

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

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