Phase difference film and polarizing plate

Abstract

To provide a retardation film which suppresses the occurrence of process defects while being conveyed and generation of bright spots when the film is pressed in, is less susceptible of whitening and / or cracking and hue unevenness, and offers superior flexibility.SOLUTION: A retardation film provided herein contains a polycarbonate resin, exhibits an in-plane retardation Re (550) in a range of 80-190 nm, a ratio Re (450) / Re (550) in a range of 0.98-1.03, and a puncture modulus of 50 gf / mm or more.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to a phase difference film and a polarizing plate. [Background technology]

[0002] In recent years, with the spread of thin-screen displays, image display devices (organic EL displays) equipped with organic EL panels have been proposed. Organic EL panels have a highly reflective metal layer, which can easily cause problems such as reflection of ambient light and background reflections. It is known that these problems can be prevented by providing a phase difference film on the viewing side. However, with conventional phase difference films, process defects such as bending, wrinkling, and dents may occur during film transport, and bright spots may occur when the film is pressed. Furthermore, when conventional phase difference films are used on the viewing side of image display devices, whitening and / or cracking may occur with use, hue unevenness may occur, and flexibility may be insufficient. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Patent No. 3325560 [Overview of the project] [Problems that the invention aims to solve]

[0004] The present invention was made to solve the above-mentioned conventional problems, and its objective is to provide a phase difference film that suppresses the occurrence of process defects during transport, suppresses the occurrence of bright spots when the film is pressed, suppresses the occurrence of whitening and / or cracks, suppresses hue unevenness, and further exhibits excellent flexibility. [Means for solving the problem]

[0005] The retardation film in the embodiment of the present invention contains a polycarbonate resin, the in-plane retardation Re(550) is 80 nm to 190 nm, Re(450) / Re(550) is 0.98 to 1.03, and the puncture elastic modulus is 50 gf / mm or more. In one embodiment, the puncture strength per unit film thickness of the retardation film is 10 gf / μm or more. In one embodiment, the breaking strength of the retardation film is 800 MPa or more, and the elongation at break is 3% or more. In one embodiment, the thickness of the retardation film is 40 μm or less. In one embodiment, the variation of Re(550) in the width direction of the retardation film is 5 nm or less. In another embodiment of the present invention, a polarizing plate with a retardation layer is provided. This polarizing plate with a retardation layer includes a polarizer and the above-mentioned retardation film bonded to at least one side of the polarizer via an adhesive layer.

Effect of the Invention

[0006] According to the embodiment of the present invention, by including a specific polycarbonate resin and setting the puncture elastic modulus within a specific range, the occurrence of process defects and color phase unevenness during conveyance can be suppressed, and a retardation film with excellent flexibility can be realized. Furthermore, by setting the puncture strength, breaking strength, and elongation at break per unit film thickness within a specific range, the occurrence of bright spots and color phase unevenness during film pressing can be suppressed, and a retardation film with excellent crack resistance can be realized.

Mode for Carrying Out the Invention

[0007] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to these embodiments.

[0008] (Definition of Terms and Symbols) The definitions of terms and symbols in this specification are as follows. (1) Refractive Index (nx, ny, nz) "nx" is the refractive index in the direction where 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).

[0009] A. Retardation film The retardation film according to an embodiment of the present invention contains a polycarbonate resin. The retardation film according to an embodiment of the present invention is typically a stretched film of a polycarbonate resin film.

[0010] The in-plane retardation Re(550) of the above retardation film is 80 nm to 190 nm, more preferably 10 nm to 160 nm. That is, the retardation film can function as a λ / 4 retardation plate.

[0011] The above retardation film exhibits flat wavelength dispersion characteristics where the retardation value hardly changes with the wavelength of the measurement light. Re(450) / Re(550) of the retardation film is 0.98 to 1.03, preferably 0.99 to 1.03, and more preferably 1.00 to 1.03. By using a polycarbonate-based resin having such Re(450) / Re(550), excellent antireflection characteristics can be realized.

[0012] The puncture modulus of the above-mentioned phase difference film is 50 gf / mm or more, preferably 100 gf / mm or more, and more preferably 150 gf / mm or more. The puncture modulus is determined by dividing the force (gf) just before the film breaks (or tears) when a needle (puncture jig) is punctured perpendicularly to the main surface of the film by the strain (mm) at that time. By having the above-mentioned puncture modulus of elasticity of the phase difference film, the occurrence of process defects during transport and the occurrence of hue unevenness can be suppressed, and a phase difference film with excellent flexibility can be obtained.

[0013] The puncture strength per unit thickness of the above-mentioned phase difference film is preferably 10 gf / μm or more, more preferably 15 gf / μm or more, and even more preferably 20 gf / μm or more. Puncture strength per unit thickness refers to the strength at which the film tears when a needle is lowered perpendicularly to the film, divided by its thickness. By having the above-mentioned puncture strength per unit thickness of the phase difference film, a phase difference film can be obtained in which the occurrence of bright spots and hue unevenness during film indentation is suppressed.

[0014] The breaking strength of the above-mentioned phase difference film is preferably 800 MPa or more, and the elongation at break is preferably 3% or more. The breaking strength of the phase difference film is more preferably 1500 MPa or more, and even more preferably 2500 MPa or more. The upper limit of the breaking strength of the phase difference film is, for example, 7000 MPa. Furthermore, the elongation at break of the phase difference film is more preferably 4% or more, and even more preferably 6% or more. The upper limit of the elongation at break of the phase difference film may be, for example, 300%. Breaking strength refers to the stress at which the film breaks in a tensile test. Elongation at break refers to the strain (elongation rate) at which the film breaks. By having the breaking strength and elongation at break of the phase difference film within the above ranges, the occurrence of hue unevenness is suppressed, and a phase difference film with excellent crack resistance can be obtained.

[0015] The thickness of the phase difference film is preferably 40 μm or less, and more preferably 35 μm or less. The lower limit of the phase difference film thickness may be, for example, 5 μm. Having the phase difference film thickness within this range allows for suitable application of the phase difference film to thin devices.

[0016] The variation in Re(550) in the width direction of the above-mentioned phase difference film is preferably 5 nm or less, more preferably 3 nm or less, and even more preferably 2 nm or less. The lower limit of the variation in Re(550) in the width direction of the phase difference film may be, for example, 0.5 nm. By defining the variation in Re(550) within such a range, good optical uniformity of the phase difference film can be achieved.

[0017] In the above phase difference film, the absolute value of the rate of change of the in-plane phase difference Re(550) after 500 hours under conditions of a temperature of 65°C and a humidity of 90% is preferably 3% or less, and more preferably 2% or less. The lower limit of the absolute value of the rate of change may be, for example, 0.01%. The above phase difference rate of change is |(Re 500 It is expressed as -Re0) / Re0|×100(%). Re0 is the in-plane phase difference (nm) of the phase difference film before the start of the test, and Re 500 This represents the in-plane phase difference (nm) of the phase difference film after testing. Because the absolute value of the rate of change of the in-plane phase difference Re(550) of the phase difference film is within this range, when the phase difference film is applied to an image display device, the hue change due to phase difference at each location on the image display device is reduced, and the occurrence of color unevenness on the display can be suppressed.

[0018] The moisture permeability of the above-mentioned phase difference film is preferably 150 g / m². 2 • Less than 24 hours, more preferably 120 g / m² 2 • Less than 24 hours. The lower limit of moisture permeability is, for example, 1 g / m². 2 This can be 24 hours. If the moisture permeability of the phase difference film is within this range, changes in the phase difference under humid conditions can be suppressed.

[0019] The absolute value of the photoelastic coefficient of the above-mentioned retardation film 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, and even 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 of the retardation film is within such a range, when shrinkage stress occurs during heating, a change in retardation is unlikely to occur. As a result, when the retardation film is applied to an image display device, uneven heat distribution of the image display device can be well prevented.

[0020] According to an embodiment of the present invention, as described above, a retardation film that satisfies a desired in-plane retardation, wavelength dispersion characteristics, and thickness, and further suppresses the occurrence of process defects during conveyance, suppresses the occurrence of bright spots when the film is pushed in, suppresses the occurrence of whitening and / or cracks, suppresses hue unevenness, and is excellent in flexibility can be obtained. Such a retardation film can be suitably used for televisions, foldable and / or foldable image display devices, and public information displays (PIDs).

[0021] B. Constituent Materials As described above, the retardation film is typically a stretched film of a polycarbonate resin film.

[0022] (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 is produced by reacting at least a dihydroxy compound containing at least a dihydroxy compound having at least one bonding structure -CH2-O- in the molecule and a carbonic acid diester in the presence of a polymerization catalyst.

Chemical Formula

[0023] Here, any compound having the bonding structure represented by structural formula (1) can be used as the dihydroxy compound having two alcoholic hydroxyl groups, containing a linking group -CH2-O- in the molecule, and capable of reacting with diester carbonate in the presence of a polymerization catalyst to produce polycarbonate. Multiple types may be used in combination. Furthermore, a dihydroxy compound not having the bonding structure represented by structural formula (1) may also be used as the dihydroxy compound for the polycarbonate resin according to the present invention. Hereinafter, the dihydroxy compound having the bonding structure represented by structural formula (1) may be abbreviated as dihydroxy compound (A), and the dihydroxy compound not having the bonding structure represented by structural formula (1) may be abbreviated as dihydroxy compound (B).

[0024] (Dihydroxy compound (A)) In dihydroxy compound (A), the "linking group -CH2-O-" refers to a structure that forms a molecule by bonding with atoms other than hydrogen atoms. In this linking group, carbon atoms are most preferred as atoms to which at least one oxygen atom can be bonded, or atoms to which carbon atoms and oxygen atoms can be bonded simultaneously. The number of "linking groups -CH2-O-" in dihydroxy compound (A) is preferably 1 or more, more preferably 2 to 4.

[0025] More specifically, dihydroxy compounds (A) include, for example, 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, and 9,9-bis(4-(2 A fluorene with aromatic groups in its side chain and attached to an aromatic group in its main chain, as exemplified by 9,9-(hydroxyethoxy)-3-cyclohexylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-phenylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-tert-butyl-6-methylphenyl)fluorene, and 9,9-bis(4-(3-hydroxy-2,2-dimethylpropoxy)phenyl)fluorene, has aromatic groups in its side chain and is attached to an aromatic group in its main chain. Compounds containing a tetra group, 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] [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[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 Bis(hydroxyalkoxyaryl)alkanes, such as exemplified by [l]propane; bis(hydroxyalkoxyaryl)cycloalkanes, such as exemplified by 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; 4,4'-bis(2-hydroxyethoxy)diphenyl ether, 4,4'-bis(2-hydroxyethoxy)-3,3'- Dihydroxyalkoxydiaryl ethers, such as dimethyldiphenyl ether; bishydroxyalkoxyaryl sulfides, such as 4,4'-bis(2-hydrochyethoxyphenyl) sulfide; bishydroxyalkoxyaryl sulfides, such as 4,4'-bis[4-(2-dihydroxyethoxy)-3-methylphenyl] sulfide; bishydroxyalkoxyaryl sulfides, such as 4,4'-bis(2-hydrochyethoxyphenyl) sulfoxide; bishydroxyalkoxyaryl sulfides, such as 4,4'-bis[4-(2-dihydroxyethoxy)-3-methylphenyl] sulfoxide. Bishydroxyalkoxyaryl sulfones, such as foxides, 4,4'-bis(2-hydroxyethoxyphenyl)sulfone, 4,4'-bis[4-(2-dihydroxyethoxy)-3-methylphenyl]sulfone, 1,4-bishydroxyethoxybenzene, 1,3-bishydroxyethoxybenzene, 1,2-bishydroxyethoxybenzene, 1,3-bis[2-[4-(2-hydroxyethoxy)phenyl]propyl]benzene, 1,4-bis[2-[4-(2-hydroxyethoxy)phenyl]propyl]benzene, 4,Examples include 4'-bis(2-hydroxyethoxy)biphenyl, 1,3-bis[4-(2-hydroxyethoxy)phenyl]-5,7-dimethyladamantane, anhydrous sugar alcohols represented by the dihydroxy compound shown in formula (4) below, and compounds having a cyclic ether structure such as spiroglycols represented by the general formula (6) below. These may be used individually or in combination of two or more.

[0026] [ka]

[0027] These dihydroxy compounds (A) may be used individually or in combination of two or more. In the present invention, examples of dihydroxy compounds represented by formula (4) include isosorbide, isomannide, and isoidette, which are stereoisomers of each other, and these may be used individually or in combination of two or more.

[0028] Of the dihydroxy compounds (A), isosorbide, obtained by dehydration condensation of sorbitol produced from various starches that are abundant and readily available as resources, is most preferred in terms of ease of acquisition and production, optical properties, and moldability. In the present invention, isosorbide is preferably used as the dihydroxy compound (A).

[0029] (Dihydroxy compound (B)) In the present invention, a dihydroxy compound other than dihydroxy compound (A), such as dihydroxy compound (B), may be used as the dihydroxy compound. For example, dihydroxy compound (B) can be alicyclic dihydroxy compounds, aliphatic dihydroxy compounds, oxyalkylene glycols, aromatic dihydroxy compounds, or diols having a cyclic ether structure, and can be used together with dihydroxy compound (A), for example, the dihydroxy compound represented by formula (4), as the dihydroxy compound that forms the constituent unit of the polycarbonate.

[0030] The alicyclic dihydroxy compound that can be used in the present invention is not particularly limited, but preferably a compound that usually contains a five-membered ring structure or a six-membered ring structure. The six-membered ring structure may also be fixed in a chair or boat shape by covalent bonds. The heat resistance of the resulting polycarbonate can be increased by the alicyclic dihydroxy compound having a five-membered ring or a six-membered ring structure. The number of carbon atoms in the alicyclic dihydroxy compound is usually 70 or less, preferably 50 or less, and more preferably 30 or less. The higher this value, the higher the heat resistance, but the more difficult the synthesis, the more difficult the purification, and the higher the cost. The lower the number of carbon atoms, the easier the purification and the easier the availability.

[0031] Examples of alicyclic dihydroxy compounds containing a five-membered ring structure or a six-membered ring structure that can be used in the present invention include alicyclic dihydroxy compounds represented by the following general formulas (II) or (III). HOCH2-R 1 -CH2OH (II) HO-R 2 -OH (III) (In formulas (II) and (III), R 1 , R 2 (Each of these represents a cycloalkylene group with 4 to 20 carbon atoms.) As cyclohexanedimethanol, which is an alicyclic dihydroxy compound represented by the above general formula (II), in general formula (II), R 1 The following general formula (IIa) (wherein R 3 The group represents an alkyl group or hydrogen atom having 1 to 12 carbon atoms. This group includes various isomers represented by ( ). Specific examples of such isomers include 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, and 1,4-cyclohexanedimethanol.

[0032] [ka]

[0033] Tricyclodecanedimethanol and pentacyclopentadecanedimethanol, which are alicyclic dihydroxy compounds represented by the above general formula (II), are as follows: In general formula (II), R 1 This includes various isomers represented by the following general formula (IIb) (wherein n represents 0 or 1).

[0034] [ka]

[0035] Decalindimethanol or tricyclotetradecanedimethanol, which are alicyclic dihydroxy compounds represented by the above general formula (II), are as follows: In general formula (II), R 1 This includes various isomers represented by the following general formula (IIc) (wherein m represents 0 or 1). Specific examples of such isomers include 2,6-decalingimethanol, 1,5-decalingimethanol, and 2,3-decalingimethanol.

[0036] [ka]

[0037] Furthermore, norbornane dimethanol, which is an alicyclic dihydroxy compound represented by the above general formula (II), is defined as R in general formula (II). 1 This includes various isomers represented by the following general formula (IId). Specific examples of such isomers include 2,3-norbornanedimethanol and 2,5-norbornanedimethanol.

[0038] [ka]

[0039] Adamantane dimethanol, which is an alicyclic dihydroxy compound represented by general formula (II), has R in general formula (II). 1This includes various isomers represented by the following general formula (IIe). Specific examples of such isomers include 1,3-adamantanedimethanol.

[0040] [ka]

[0041] Furthermore, cyclohexanediol, which is an alicyclic dihydroxy compound represented by the above general formula (III), has R in general formula (III). 2 The following general formula (IIIa) (wherein R 3 The group represents an alkyl group or hydrogen atom having 1 to 12 carbon atoms. This group includes various isomers represented by ( ). Specifically, examples of such isomers include 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, and 2-methyl-1,4-cyclohexanediol.

[0042] [ka]

[0043] Tricyclodecanediol and pentacyclopentadecanediol, which are alicyclic dihydroxy compounds represented by the above general formula (III), are as follows: In general formula (III), R 2 This includes various isomers represented by the following general formula (IIIb) (wherein n represents 0 or 1).

[0044] [ka]

[0045] Decalindiol or tricyclotetradecanediol, which are alicyclic dihydroxy compounds represented by the above general formula (III), are as follows: In general formula (III), R 2This includes various isomers represented by the following general formula (IIIc) (where m represents 0 or 1). Specifically, such isomers include 2,6-decalindiol, 1,5-decalindiol, and 2,3-decalindiol.

[0046] [ka]

[0047] Norbornanediol, which is an alicyclic dihydroxy compound represented by the above general formula (III), is as follows: In general formula (III), R 2 This includes various isomers represented by the following general formula (IIId). Specifically, examples of such isomers include 2,3-norbornanediol and 2,5-norbornanediol.

[0048] [ka]

[0049] Adamantanediol, which is an alicyclic dihydroxy compound represented by the above general formula (III), is as follows: In general formula (III), R 2 This includes various isomers represented by the following general formula (IIIe). Specifically, examples of such isomers include 1,3-adamantanediol.

[0050] [ka]

[0051] Among the specific examples of alicyclic dihydroxy compounds described above, cyclohexanedimethanols, tricyclodecanedimethanols, adamantanediols, and pentacyclopentadecanedimethanols are particularly preferred, and from the viewpoint of availability and ease of handling, 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,2-cyclohexanedimethanol, and tricyclodecanedimethanol are preferred. In the present invention, tricyclodecanedimethanol is preferably used as the dihydroxy compound (B).

[0052] Examples of 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 oxyalkylene glycols that can be used in the present invention include diethylene glycol, triethylene glycol, tetraethylene glycol, and polyethylene glycol.

[0053] Aromatic dihydroxy compounds that can be used in the present 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, 1,1-bis(4-hydroxyphenyl)ethane, 3,3-bis(4- Examples include 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, and 9,9-bis(4-hydroxy-2-methylphenyl)fluorene.

[0054] Examples of diols having a cyclic ether structure that can be used in the present invention include spiroglycols and dioxane glycols. The above-mentioned exemplary compounds are examples of 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 to these. These compounds can be used one or more together with a dihydroxy compound represented by formula (4).

[0055] By using these dihydroxy compounds (B), effects such as improved flexibility, improved heat resistance, and improved moldability can be obtained depending on the application. The proportion of dihydroxy compound (A), for example, the dihydroxy compound represented by formula (4), to the total 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, even more preferably 60 mol% or more, preferably 90 mol% or less, more preferably 80 mol% or less, and even more preferably 70 mol% or less. If the proportion of constituent units derived from other dihydroxy compounds is too high, it may reduce performance such as optical properties.

[0056] When using an alicyclic dihydroxy compound among the other dihydroxy compounds mentioned above, the total ratio of dihydroxy compound (A), for example, the dihydroxy compound represented by formula (4), and the alicyclic dihydroxy compound to the total dihydroxy compounds constituting the 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.

[0057] Furthermore, regarding the content ratio of constituent units derived from dihydroxy compound (A), for example, a dihydroxy compound represented by formula (4), and constituent units derived from alicyclic dihydroxy compounds in the polycarbonate resin according to the present invention, any ratio can be selected, but a ratio of constituent units derived from dihydroxy compound represented by formula (4) to constituent units derived from alicyclic dihydroxy compounds = 1:99 to 99:1 (mol%) is preferred, and a ratio of constituent units derived from dihydroxy compound represented by formula (4) to constituent units derived from alicyclic dihydroxy compounds = 10:90 to 90:10 (mol%) is particularly preferred. If the amount of constituent units derived from dihydroxy compound represented by formula (4) is greater than the above range and the amount of constituent units derived from alicyclic dihydroxy compounds is less, it becomes easier to color, and conversely, if the amount of constituent units derived from dihydroxy compound represented by formula (4) is less and the amount of constituent units derived from alicyclic dihydroxy compounds is greater, the molecular weight tends to be less likely to increase.

[0058] Furthermore, when using aliphatic dihydroxy compounds, oxyalkylene glycols, aromatic dihydroxy compounds, or diols having a cyclic ether structure, the ratio of dihydroxy compound (A), for example, the dihydroxy compound represented by formula (4), to the total ratio of these dihydroxy compounds to the total dihydroxy compounds constituting the polycarbonate is not particularly limited and can be selected in any ratio. Similarly, the ratio of constituent units derived from dihydroxy compound (A), for example, the dihydroxy compound represented by formula (4), to constituent units derived from these dihydroxy compounds is not particularly limited and can be selected in any ratio.

[0059] Details of polycarbonate resins are described, for example, in Japanese Patent Publication No. 2012-31370 (Japanese Patent No. 5448264). The description in said patent document is incorporated herein by reference.

[0060] C. Method for manufacturing phase difference film A method for manufacturing a phase difference 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 C above.

[0061] In one embodiment, the phase difference film can be manufactured by biaxial stretching. The biaxial stretching may be simultaneous biaxial stretching or sequential biaxial stretching. The stretching ratio in the longitudinal direction is preferably greater than 1.0x and 2.0x or less, and more preferably 1.1x to 1.5x. The stretching ratio in the width direction is preferably 1.6x to 2.2x, and more preferably 1.8x to 2.0x. By stretching a film formed from the above polycarbonate resin at such stretching ratios, not only desired optical properties but also very excellent mechanical properties (e.g., flexibility, crack resistance) can be achieved.

[0062] The stretching temperature of the above resin film is preferably Tg-30°C to Tg+30°C, more preferably Tg-10°C to Tg+25°C, and even more preferably Tg+8°C to Tg+20°C. By stretching at such temperatures, a phase difference film having appropriate properties for the present invention can be obtained. Note that Tg is the glass transition temperature of the constituent material of the film.

[0063] D. Polarizing plate with retardation layer The phase difference films described in sections A to C above may be provided as a laminate with other phase difference films and / or optical components. In one embodiment, the phase difference film may be provided as a laminate with a polarizer (polarizer with phase difference layer). Therefore, the present invention encompasses polarizers with phase difference layer having the above phase difference film. In the phase difference film, the angle between the absorption axis of the polarizer of the polarizer and the slow axis of the phase difference film may be appropriately set depending on the application and purpose. In one embodiment, the above angle is preferably 40° to 50°, more preferably 42° to 48°, and even more preferably about 45°.

[0064] A polarizing plate with a phase difference layer typically comprises a polarizer and the phase difference film bonded to at least one side of the polarizer via an adhesive layer. The polarizer may have a protective layer on at least one side. Furthermore, the polarizing plate may have an adhesive layer and a separator on the side opposite to the viewing side.

[0065] Any suitable polarizer can be used as the polarizer. For example, the resin film forming the polarizer may be a single layer resin film or a laminate of two or more layers.

[0066] Specific examples of polarizers composed of a single layer of resin film include hydrophilic polymer films such as polyvinyl alcohol (PVA) films, partially formalized PVA films, and partially saponified ethylene-vinyl acetate copolymer films, which have been subjected to dyeing and stretching treatments with dichroic substances such as iodine or dichroic dyes, as well as polyene-based oriented films such as dehydrated PVA or dehydrochlorinated polyvinyl chloride. Preferably, polarizers obtained by dyeing a PVA film with iodine and uniaxially stretching are used because they have excellent optical properties.

[0067] The above-mentioned iodine dyeing is carried out, for example, by immersing the PVA film in an iodine aqueous solution. The stretching ratio for the above-mentioned uniaxial stretching is preferably 3 to 7 times. Stretching may be performed after the dyeing treatment, or during the dyeing process. Alternatively, dyeing may be performed after stretching. If necessary, the PVA film may be subjected to swelling, crosslinking, washing, drying, etc. For example, immersing the PVA film in water and washing it before dyeing can not only clean dirt and anti-blocking agents from the surface of the PVA film, but also swell the PVA film to prevent uneven dyeing.

[0068] Specific examples of polarizers obtained using laminates include polarizers obtained using a laminate of a resin substrate and a PVA-based resin layer (PVA-based resin film) laminated on the resin substrate, or polarizers obtained using a laminate of a resin substrate and a PVA-based resin layer coated on the resin substrate. Details of the manufacturing method of such polarizers are described, for example, in Japanese Patent Application Publication No. 2012-73580 (Japanese Patent No. 5414738). The description in said patent document is incorporated herein by reference. The entire description of said publication is incorporated herein by reference.

[0069] In one embodiment, the thickness of the polarizer is preferably 1 μm to 25 μm, more preferably 3 μm to 10 μm, and even more preferably 3 μm to 8 μm. When the thickness of the polarizer is within this range, curling during heating can be well suppressed, and good appearance durability during heating can be obtained.

[0070] The protective layer is formed from any suitable protective film that can be used as a protective film for the polarizer. Specific examples of materials that make up the main component of the protective film include cellulosic resins such as triacetylcellulose (TAC), polyester, polyvinyl alcohol, polycarbonate, polyamide, polyimide, polyethersulfone, polysulfone, polystyrene, polynorbornene, polyolefin, (meth)acrylic, acetate, and other transparent resins. Thermosetting resins or UV-curing resins such as (meth)acrylic, urethane, (meth)acrylic urethane, epoxy, and silicone are also acceptable. In addition, glassy polymers such as siloxane polymers can also be used. Polymer films described in Japanese Patent Application Publication No. 2001-343529 (WO01 / 37007) can also be used. As materials for this film, for example, a resin composition containing a thermoplastic resin having substituted or unsubstituted imide groups in its side chains, and a thermoplastic resin having substituted or unsubstituted phenyl groups and nitrile groups in its side chains can be used. Examples include a resin composition having an alternating copolymer of isobutene and N-methylmaleimide, and an acrylonitrile-styrene copolymer. The polymer film may be, for example, an extruded product of the above resin composition.

[0071] The thickness of the protective layer is preferably 10 μm to 100 μm. The protective layer may be laminated to the polarizer via an adhesive layer (specifically, an adhesive layer or a tack layer), or it may be laminated in close contact with the polarizer (without an adhesive layer). If necessary, a surface treatment layer such as a hard coat layer, an anti-glare layer, and an anti-reflective layer may be formed on the protective layer located on the outermost surface of the polarizing plate with a phase difference layer.

[0072] The polarizing plate with a phase difference layer described above can be used on the viewing side of an image display device. Furthermore, the phase difference layer in the polarizing plate with a phase difference layer may be placed on the viewing side or on the display cell side.

[0073] Any suitable adhesive can be used as the adhesive forming the adhesive layer. Examples of base resins for the adhesive include acrylic resins, styrene resins, silicone resins, urethane resins, and rubber resins. Such base resins are described, for example, in Japanese Patent Publication No. 2015-120337 (Japanese Patent No. 6457789) or Japanese Patent Publication No. 2011-201983. The descriptions in these publications are incorporated herein by reference. Examples of crosslinking agents that may be included in the adhesive include isocyanate compounds, epoxy compounds, and aziridine compounds. The adhesive may also contain, for example, a silane coupling agent. The formulation of the adhesive can be appropriately set according to the purpose and desired properties.

[0074] The storage modulus of the adhesive layer is preferably 1.0 × 10⁻⁶. 4 Pa~1.0×10 7 Pa, more preferably 2.0 × 10 4 Pa~5.0×10 6 The storage modulus of the adhesive layer is within this range, which helps to suppress blocking during roll formation. The storage modulus can be determined, for example, from dynamic viscoelasticity measurements at a temperature of 23°C and an angular velocity of 0.1 rad / s.

[0075] The thickness of the adhesive layer is preferably 1 μm to 60 μm, and more preferably 3 μm to 30 μm. If the thickness is too thin, the adhesiveness will be insufficient, and air bubbles may get trapped at the adhesive interface. If the thickness is too thick, problems such as the adhesive oozing out are more likely to occur.

[0076] In practical terms, a separator is temporarily attached to the adhesive layer surface in a peelable manner until the phase difference film is actually used. Examples of separators include plastic films (e.g., polyethylene terephthalate (PET), polyethylene, polypropylene), nonwoven fabrics, or paper, surface-coated with release agents such as silicone-based release agents, fluorine-based release agents, or long-chain alkyl acrylate-based release agents. The thickness of the separator can be any appropriate thickness depending on the purpose. For example, the separator thickness is 10 μm to 100 μm. [Examples]

[0077] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. The measurement and evaluation methods for each characteristic are as follows. (1) In-plane phase difference and wavelength dispersion characteristics The phase difference films obtained in the examples and comparative examples were cut to a length of 4 cm and a width of 4 cm to be used as measurement samples. The in-plane phase difference Re(550) of these measurement samples was measured using an Axometrics product called "Axoscan". Furthermore, Re(450) was also measured, and Re(450) / Re(550) was calculated. (2) Thickness Thicknesses of 10 μm or less were measured using an interferometer (Otsuka Electronics Co., Ltd., product name "MCPD-3000"). Thicknesses exceeding 10 μm were measured using a digital micrometer (Anritsu Corporation, product name "KC-351C"). (3) Moisture permeability The phase difference films obtained in the examples and comparative examples were subjected to a moisture permeability test (cup method) in accordance with JIS Z0208, in an atmosphere of 40°C and 92% RH, over an area of ​​1 m². 2 The amount of water vapor (g) passing through the sample over 24 hours was measured. (4) Phase difference change The phase difference films obtained in the examples and comparative examples were cut into 5cm x 5cm pieces, adhesive was applied to one side using a hand roller, and the adhesive side was attached to one side of alkali glass to obtain test specimens. The test specimens were stored in an oven at 65°C and 90% humidity for 500 hours (humidification test), and the change in phase difference (%) before and after the test was calculated. (5) Variation in phase difference (1) Similarly, the in-plane phase difference Re(550) of the phase difference films obtained in the examples and comparative examples was measured. Nine measurements were taken in the width direction of the phase difference film, and the difference between the maximum and minimum phase difference values ​​was defined as the phase difference variation. (6) Puncture elastic modulus The puncture modulus was determined by dividing the force (gf) just before the phase difference film in the examples and comparative examples broke (or ripped) by the strain (mm) at that time, when a needle (puncture jig) was punctured perpendicularly to the main surface of the phase difference film. A needle with a tip diameter of 1 mmφ and a radius of 0.5R was used. The needle puncture speed was set to 0.33 cm / second. The measurement was performed in an environment with a temperature of 23°C. (7) Puncture strength A testing machine equipped with a needle with a tip diameter of 1 mmφ and a radius of 0.5R was used. The phase difference film was sandwiched between two jigs with a circular hole in the center and fixed to the testing machine. The needle was lowered vertically through the hole in the jig onto the phase difference film, and the strength at which the phase difference film tore was measured. The test conditions were a temperature of 23±3℃ and a puncture speed of 0.33 cm / sec. Puncture tests were performed on 12 test samples, and the average value was divided by the thickness of the phase difference film to determine the puncture strength per unit thickness of the phase difference film. (8) Breaking strength and elongation at break The phase difference films obtained in the examples and comparative examples were cut into strips 1 cm wide and 13 cm long. Tensile tests were then performed using an Autograph ASG-50D tensile testing machine (manufactured by Shimadzu Corporation) at a tensile speed of 200 mm / min, a chuck distance of 50 mm, and room temperature (23°C). The stress at which the phase difference film broke was determined as the breaking strength, and the strain (elongation) at which the phase difference film broke was also determined as the breaking strength. (9) Adhesiveness A laminate was obtained by bonding the phase difference film and polarizer obtained in the examples and comparative examples. The obtained laminate was cut to 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. An incision was made between the phase difference film and the polarizer with a utility knife, and the phase difference film and polarizer were peeled off at a peeling speed of 1000 mm / min in the 90-degree direction using a Tensilon universal tester RTC (manufactured by A&D Company, Limited), and the peel strength (N / 15 mm) was measured. A peel strength of 1 N / 15 mm or more was considered good, and a peel strength of less than 1 N / 15 mm was considered poor. (10) Runability (evaluation of process defects during transport) When the phase difference films obtained in the examples and comparative examples were transported by guide rolls at a speed of 5 m / min to 40 m / min, they were considered good if no defects such as folds, scratches, or dents occurred (i.e., they could be transported without problems), and defective if folds, scratches, or dents occurred. (11) Flexibility (MIT test) The MIT test was conducted in accordance with JIS P 8115. Specifically, the phase difference films obtained in the examples and comparative examples were cut to a length of 15 cm and a width of 1.5 cm to be used as test samples. The test samples were mounted on an MIT folding fatigue tester BE-202 (manufactured by Tester Industry Co., Ltd.) (load 1.0 kgf, clamp radius: 0.38 mm), and repeatedly folded at a test speed of 90 cpm and a folding angle of 90°. The number of folds at which the test sample broke was taken as the test value. Samples with an empirical value of 500 or more folds were classified as good, and those with less than 500 folds were classified as poor. (12) Hue unevenness A laminate was obtained by bonding the phase difference film and polarizer obtained in the examples and comparative examples. The laminate was cut to a predetermined size, and the surface of the phase difference film was subjected to corona treatment. The corona-treated surface of the laminate was bonded to an alkali-free glass plate via an acrylic adhesive (20 μm) to prepare a test sample. This test sample was placed on an organic EL device substitute with the glass plate surfaces facing each other, and hue unevenness (smudges) was observed visually under fluorescent light and evaluated according to the following criteria. Good: No significant hue inconsistencies were observed. Defect: The color unevenness was significant and unacceptable for practical use. (13) Evaluation of the bright spot when pressed A sample identical to the one evaluated in the puncture strength test was bonded to a polarizer, and the film side was pressed with a force of 10 gf / μm using a puncture testing machine. Then, one polarizer was prepared so as to be at a 90° axis with the polarizer in question, and transmitted light was passed through from the opposite side of the puncture-tested film under crossed nicols. If no bright spots were seen, the sample was considered good; if bright spots were seen, it was considered poor. (14) Crack resistance The phase difference films obtained in the examples and comparative examples were subjected to a heat shock test from -40°C to 80°C for 300 cycles. A film was considered good if no cracks larger than 300 μm occurred, and poor if cracks larger than 300 μm occurred.

[0078] [Example 1] 1. Preparation of resin film 81.98 parts by mass of isosorbide (hereinafter sometimes abbreviated as "ISB"), 47.19 parts by mass of tricyclodecanedimethanol (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 were added to a reaction vessel. In the first step of the reaction, under a nitrogen atmosphere, the heating vessel temperature was raised to 150°C, and the raw materials were dissolved while stirring as needed (for about 15 minutes). Next, the pressure was increased from atmospheric pressure to 13.3 kPa, and the heating vessel temperature was raised to 190°C over 1 hour, while the generated phenol was removed from the reaction vessel. After maintaining the entire reaction vessel at 190°C for 15 minutes, the second step involved increasing the pressure inside the reaction vessel to 6.67 kPa and raising the heating tank temperature to 230°C over 15 minutes to remove the generated phenol. As the stirring torque of the stirrer increased, the temperature was raised to 250°C over 8 minutes, and the pressure inside the reaction vessel was reduced to below 0.200 kPa to further remove the generated phenol. After reaching the predetermined stirring torque, the reaction was terminated, and the resulting reactants were pushed into water to obtain polycarbonate resin pellets. The obtained polycarbonate resin was vacuum-dried at 80°C for 5 hours, and then film was produced using a film-making apparatus equipped with a single-screw extruder (manufactured by Toshiba Machine Co., Ltd., cylinder setting temperature: 250°C), a T-die (width 300 mm, setting temperature: 250°C), a chill roll (setting temperature: 120~130°C), and a winding machine. , A recarbonate resin film was fabricated.

[0079] 2. Preparation of phase difference film An unstretched polycarbonate resin film was subjected to preheating and simultaneous biaxial stretching using a simultaneous biaxial stretching machine to obtain a phase difference film. The preheating temperature was 137°C and the stretching temperature was 140°C, with a stretching ratio of 1.2 times in the longitudinal direction and 1.9 times in the width direction. The obtained phase difference film had a wavelength dispersion of 1.025, an in-plane phase difference Re(550) of 118 nm, a thickness of 30 μm, and a moisture permeability of 110 g / m². 2The time interval was 24 hours, the phase difference change was 1%, and the in-plane phase difference variation was 2 nm. Furthermore, the puncture modulus of the phase difference film was 435 gf / mm, the puncture strength was 27.8 gf / μm, the breaking strength was 2480 MPa, and the elongation at break was 5.8%. The obtained phase difference film was subjected to the evaluations described in (9) to (14) above. The results are shown in Table 1.

[0080] [Example 2] A phase difference film was obtained in the same manner as in Example 1, except that the preheating temperature was 137°C, the stretching temperature was 140°C, the stretching ratio in the longitudinal direction was 1.2 times, and the stretching ratio in the width direction was 1.9 times. The obtained phase difference film had a wavelength dispersion value of 1.022, an in-plane phase difference Re(550) of 144 nm, a thickness of 30 μm, and a moisture permeability of 82 g / m². 2 The phase difference change was 0.8% over 24 hours, and the in-plane phase difference variation was 2 nm. Furthermore, the puncture modulus of the phase difference film was 446 gf / mm, the puncture strength was 28 gf / μm, the breaking strength was 2480 MPa, and the elongation at break was 5.8%. The obtained phase difference film was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0081] [Example 3] A phase difference film was obtained in the same manner as in Example 1, except that the preheating temperature was 137°C, the stretching temperature was 140°C, the stretching ratio in the longitudinal direction was 1.2 times, and the stretching ratio in the width direction was 1.9 times. The obtained phase difference film had a wavelength dispersion value of 1.026, an in-plane phase difference Re(550) of 157 nm, a thickness of 30 μm, and a moisture permeability of 81 g / m². 2 The time interval was 24 hours, the phase difference change was 0.9%, and the in-plane phase difference variation was 2 nm. Furthermore, the puncture modulus of the phase difference film was 457 gf / mm, the puncture strength was 29 gf / μm, the breaking strength was 2480 MPa, and the elongation at break was 5.8%. The obtained phase difference film was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0082] [Comparative Example 1] A phase difference film was obtained in the same manner as in Example 1, except that a commercially available cycloolefin resin film (manufactured by Zeon Corporation, trade name "Zeonor") was used as the resin film, and the stretching was performed at a preheating temperature of 140°C, a stretching temperature of 143°C, a stretching ratio of 1.2 times in the longitudinal direction, and a stretching ratio of 1.9 times in the width direction. The obtained phase difference film had a wavelength dispersion value of 1.01, an in-plane phase difference Re(550) of 140 nm, a thickness of 52 μm, and a moisture permeability of 6 g / m². 2 The phase difference change was 0.6% over 24 hours, and the in-plane phase difference variation was 2 nm. Furthermore, the puncture modulus of the phase difference film was 304 gf / mm, the puncture strength was 17 gf / μm, the breaking strength was 2150 MPa, and the elongation at break was 0.7%. The obtained phase difference film was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0083] [Comparative Example 2] (Polymerization of polyester carbonate resins) Polymerization was carried out using a batch polymerization apparatus consisting of two vertical reactors equipped with stirring blades and reflux condensers controlled to 100°C. The mixture consisted of 29.60 parts by mass (0.046 mol) of bis[9-(2-phenoxycarbonylethyl)fluoren-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 × 10⁻¹⁶ calcium acetate monohydrate as a catalyst. -2 Part of mass (6.78×10 -5A mol (mol) of polymer was added. After purging the reactor with reduced pressure using nitrogen, the reactor was heated with a heat transfer medium, and stirring was started when the internal temperature reached 100°C. Forty minutes after the start of heating, the internal temperature was raised to 220°C, and while controlling the pressure to maintain this temperature, the pressure was reduced to 13.3 kPa 90 minutes after reaching 220°C. The phenol vapor produced as a by-product of the polymerization reaction was directed to a reflux condenser at 100°C, and the monomer components contained in the phenol vapor were returned to the reactor. The uncondensed phenol vapor was directed to a condenser at 45°C and recovered. Nitrogen was introduced into the first reactor to restore the pressure to atmospheric pressure, and then the oligomerized reaction mixture in the first reactor was transferred to the second reactor. Next, heating and depressurization in the second reactor were started, and the internal temperature reached 240°C and the pressure 0.2 kPa in 50 minutes. Polymerization was then allowed to proceed until the predetermined stirring power was reached. Once the predetermined power level was reached, nitrogen was introduced into the reactor to restore pressure, and the resulting polyester carbonate resin was extruded into water. The strands were then cut to obtain pellets.

[0084] (Preparation of phase difference film) The obtained polyester carbonate resin (pellets) was vacuum-dried at 80°C for 5 hours. Then, a 130 μm thick long resin film was produced using a film-making apparatus equipped with a single-screw extruder (Toshiba Machine Co., Ltd., cylinder setting temperature: 250°C), a T-die (width 200 mm, setting temperature: 250°C), a chill roll (setting temperature: 120-130°C), and a winding machine. The obtained long resin film was stretched while adjusting to obtain a predetermined phase difference to obtain a phase difference film with a thickness of 57 μm. The stretching conditions were a stretching temperature of 145°C and a stretching ratio of 1.2 times in the width direction. The obtained phase difference film had a wavelength dispersion of 0.855, an in-plane phase difference Re(550) of 140 nm, and a moisture permeability of 74 g / m². 2 The phase difference change was 1.7% over 24 hours, and the in-plane phase difference variation was 2 nm. Furthermore, the puncture modulus of the phase difference film was 770 gf / mm, the puncture strength was 33 gf / μm, the breaking strength was 2820 MPa, and the elongation at break was 1.5%. The obtained phase difference film was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0085] [Comparative Example 3] A phase difference film was obtained in the same manner as in Example 1, except that the preheating temperature was 137°C, the stretching temperature was 140°C, the stretching ratio in the longitudinal direction was 1.2 times, and the stretching ratio in the width direction was 1.9 times. The obtained phase difference film had a wavelength dispersion value of 1.022, an in-plane phase difference Re(550) of 140 nm, a thickness of 5 μm, and a moisture permeability of 165 g / m². 2 The time interval was 24 hours, the phase difference change was 1%, and the in-plane phase difference variation was 3 nm. Furthermore, the puncture modulus of the phase difference film was 42 gf / mm, the puncture strength was 12 gf / μm, the breaking strength was 700 MPa, and the elongation at break was 5%. The obtained phase difference film was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0086] [Table 1]

[0087] As is clear from Table 1, the phase difference film of the embodiment of the present invention is excellent in all aspects, including adhesion, runnability, flexibility, suppression of hue unevenness, suppression of bright spot generation during indentation, and crack resistance. This is presumed to be achieved by using a phase difference film containing a specific polycarbonate resin, and by keeping the puncture modulus, puncture strength per unit thickness, breaking strength, and elongation at break of the phase difference film within specific ranges. [Industrial applicability]

[0088] The phase difference film according to embodiments of the present invention is suitably used in televisions, foldable and / or collapsible image display devices, and public information displays (PIDs).

Claims

1. A stretched polycarbonate resin film having an in-plane phase difference Re(550) of 80 nm to 190 nm, a Re(450) / Re(550) ratio of 0.98 to 1.03, a puncture modulus of 150 gf / mm or more, and a thickness of 5 μm to 40 μm. The polycarbonate resin comprises a structural unit derived from a dihydroxy compound represented by formula (4), and a structural unit derived from an alicyclic dihydroxy compound represented by general formula (II) or (III). 【Chemistry 1】 HOCH 2 -R 1 -CH 2 OH (II) HO-R 2 -OH (III) (In formulas (II) and (III), R1 and R2 each represent a cycloalkylene group having 4 to 20 carbon atoms.) The proportion of the dihydroxy compound represented by formula (4) to the total dihydroxy compounds constituting the polycarbonate resin is 40 mol% or more and 90 mol% or less. The ratio of constituent units derived from the dihydroxy compound represented by formula (4) to constituent units derived from the alicyclic dihydroxy compound represented by general formula (II) or (III) in the polycarbonate resin is 10:90 to 90:10 (mol%). Phase difference film.

2. The phase difference film according to claim 1, wherein the puncture strength per unit thickness is 10 gf / μm or more.

3. A phase difference film according to claim 1 or 2, wherein the breaking strength is 800 MPa or more and the elongation at break is 3% or more.

4. A phase difference film according to any one of claims 1 to 3, wherein the variation in Re(550) in the width direction is 5 nm or less.

5. A polarizing plate with a phase difference layer, comprising a polarizer and a phase difference film according to any one of claims 1 to 4, which is bonded to at least one side of the polarizer via an adhesive layer.

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