Optical film and polarizing plate

Abstract

Provided are an optical film and a polarizing plate that are excellent in process defects in conveyance, bright spots in pressing of a film, further, in bending property, irregular shape processability, and crack resistance. An optical film is used, which contains a specific polycarbonate-based resin, has an in-plane retardation Re(550) of 10 nm or less, an Re(450) / Re(550) of 0.98 to 1.03, and a puncture modulus of 50 gf / mm or more.

Description

TECHNICAL FIELD

[0001] The present application relates to an optical film and a polarizing plate. BACKGROUND

[0002] In recent years, thinning of devices having liquid crystal displays such as television sets and smartphones has been increasingly sought. Various thin films have been proposed in order to achieve thinning of devices. However, for thin films, process defects such as bending, wrinkling, and impact marks sometimes occur in the handling of the films. Furthermore, bright spots sometimes occur when the films are pressed, and the flexibility, irregular shape processability, or crack resistance is sometimes insufficient.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT DOCUMENTS

[0005] Patent Document 1: Japanese Patent No. 3325560 SUMMARY

[0006] The problem to be solved by the invention

[0007] The present application has been made in order to solve the above-described conventional problems, and has an object to provide an optical film in which process defects in handling are suppressed, bright spots are suppressed from occurring when the film is pressed, and the flexibility, irregular shape processability, and crack resistance are excellent.

[0008] The solution to the problem

[0009] The optical film of the embodiment of the present application contains a polycarbonate-based resin, has an in-plane retardation Re(550) of 10 nm or less, an Re(450) / Re(550) of 0.98 to 1.03, and a puncture modulus of 50 gf / mm or more.

[0010] In one embodiment, the puncture strength per unit film thickness of the above-described optical film is 10 gf / μm or more.

[0011] In one embodiment, the breaking strength of the above-described optical film is 800 MPa or more, and the elongation at break is 3% or more.

[0012] In one embodiment, the thickness of the above-described optical film is 25 μm or less.

[0013] In one embodiment, the absolute value of the change rate of the in-plane retardation Re(550) of the above-described optical film after 500 hours under conditions of a temperature of 65°C and a humidity of 90% is 1% or less.

[0014] In another embodiment of the present application, a polarizing plate is provided. The polarizing plate includes a polarizing member and the optical film described above, the optical film being attached to at least one side of the polarizing member by means of an adhesive layer.

[0015] Effects of the invention

[0016] According to the embodiment of the present application, by including a specific polycarbonate-based resin and setting the puncture modulus to a specific range, an optical film in which the occurrence of process failures during conveyance is suppressed and further the bending property is excellent can be realized. Further, by setting the puncture strength, the breaking strength, and the breaking elongation per unit film thickness to a specific range, an optical film in which the occurrence of bright spots when pressing the film is suppressed and the irregular shape processability and the crack resistance are excellent can be realized. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a schematic plan view illustrating an example of an irregular shape or an irregular shape processed portion in a polarizing plate of the embodiment of the present application.

[0018] Figure 2 is a schematic plan view illustrating a modification example of an irregular shape or an irregular shape processed portion in a polarizing plate of the embodiment of the present application.

[0019] Figure 3 is a schematic plan view illustrating another modification example of an irregular shape or an irregular shape processed portion in a polarizing plate of the embodiment of the present application.

[0020] Figure 4 is a schematic plan view illustrating still another modification example of an irregular shape or an irregular shape processed portion in a polarizing plate of the embodiment of the present application. DETAILED DESCRIPTION

[0021] Hereinafter, the embodiments of the present application will be described, but the present application is not limited to these embodiments.

[0022] (Definitions of Terms and Symbols)

[0023] The definitions of the terms and symbols in the present specification are shown below.

[0024] (1) Refractive Indexes (nx, ny, nz)

[0025] "nx" is the refractive index in the direction in which the in-plane refractive index is the largest (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.

[0026] (2) In-Plane Phase Difference (Re)

[0027] "Re(λ)" is an in-plane retardation measured using light of wavelength λ nm at 23°C. For example, "Re(550)" is an in-plane retardation measured using light of wavelength 550 nm at 23°C. When the thickness of the layer (film) is set as d (nm), Re(λ) is calculated by the formula Re(λ) = (nx-ny) x d.

[0028] A. Optical film

[0029] The optical film of the embodiment of the present application contains a polycarbonate resin. Typically, the optical film of the embodiment of the present application is a polycarbonate resin film.

[0030] The in-plane retardation Re(550) of the above optical film is 10 nm or less, preferably 8 nm or less, and more preferably 5 nm or less. The lower limit of the in-plane retardation can be, for example, 0 nm.

[0031] The above optical film exhibits a flat wavelength dispersion characteristic in which the phase difference value hardly changes with the wavelength of the measuring light. The Re(450) / Re(550) of the optical 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 properties can be achieved.

[0032] The puncture modulus of the above optical 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 a value obtained by dividing the force (gf) at which the film is about to break (or crack) when a needle (puncture jig) is vertically punctured with respect to the main surface of the film by the strain (mm) at that time. By providing the optical film with the above puncture modulus, an optical film in which process failures during conveyance and the like are suppressed and further the bending properties are excellent can be obtained.

[0033] The puncture strength per unit film thickness of the above optical film is preferably 10 gf / μm or more, more preferably 15 gf / μm or more, and further preferably 20 gf / μm or more. The puncture strength per unit film thickness represents a value obtained by dividing the strength at which the film is damaged when a needle is vertically lowered with respect to the film by the thickness. By providing the film with the above puncture strength per unit film thickness, an optical film in which the occurrence of bright spots when the film is pressed is suppressed and further the irregular shape processability is excellent can be obtained.

[0034] The optical film preferably has a breaking strength of 800 MPa or more and an elongation at break of 3% or more. The optical film more preferably has a breaking strength of 1500 MPa or more and further preferably 2500 MPa or more. The upper limit of the breaking strength of the optical film is, for example, 70000 MPa. In addition, the optical film more preferably has an elongation at break of 4% or more and further preferably 6% or more. The upper limit of the elongation at break of the optical film is, for example, 300%. The breaking strength indicates the stress at which the film breaks in a tensile test. The elongation at break indicates the strain (elongation) at which the film breaks. By setting the breaking strength and the elongation at break of the optical film to the above ranges, an optical film having excellent crack resistance can be obtained.

[0035] The optical film preferably has a thickness of 25 μm or less and more preferably 20 μm or less. The lower limit of the thickness of the optical film is, for example, 0.5 μm. By setting the thickness of the optical film to the above range, the optical film is suitably applied to thin devices.

[0036] The optical film preferably has an absolute value of the change rate of the in-plane retardation Re(550) after 500 hours under conditions of a temperature of 65°C and a humidity of 90% of 1% or less, more preferably 0.5% or less, and further preferably 0.1% or less. The lower limit of the absolute value of the change rate is, for example, 0.01%. The above change rate of the retardation is represented by |(Re 500 - Re0) / Re0| x 100 (%). Re0 is the in-plane retardation (nm) of the optical film before the test, and Re 500 is the in-plane retardation (nm) of the optical film after the test. By setting the absolute value of the change rate of the in-plane retardation Re(550) of the optical film to the above range, the color phase change due to the retardation at each position on the image display device is reduced when the optical film is applied to the image display device, and the occurrence of color unevenness in display can be suppressed.

[0037] The optical film preferably has a moisture permeability of 300 g / m 2 ·24h or less, more preferably 200 g / m 2 ·24h or less, and further preferably 160 g / m 2 ·24h or less. The lower limit of the moisture permeability is, for example, 1 g / m 2 ·24h. If the moisture permeability of the optical film is in the above range, the change in the retardation under a humidified environment can be suppressed.

[0038] The optical film preferably has an absolute value of the photoelastic coefficient of 2 x 10 -11 m 2 or less, more preferably 2.0 x 10 -13 m 2 / N ~ 1.5 x 10 -11 m 2 / N, further preferably 1.0 x 10 -12 m 2 / N ~ 1.2 x 10 -11 m 2 / N. If the absolute value of the optical film's photoelastic coefficient is in this range, a phase difference change does not easily occur when shrinkage stress is generated upon heating. As a result, when the optical film is applied to an image display device, it is possible to favorably prevent thermal unevenness of the image display device.

[0039] According to the embodiment of the present application, as described above, it is possible to obtain an optical film that satisfies a desired in-plane phase difference, wavelength dispersion characteristics, and thickness, further suppresses occurrence of process failures during conveyance, suppresses generation of bright spots when the film is pressed, and is excellent in flexibility, irregular shape processability, and crack resistance. Such an optical film can be suitably used, for example, in a thin, bendable, and / or foldable EL display device.

[0040] B. Constituent Material

[0041] As described above, the optical film is, by way of example, a resin film containing a polycarbonate resin.

[0042] The polycarbonate resin of the present application contains at least a structural unit derived from a dihydroxy compound having a bonding structure represented by the following structural formula (1), which is produced by allowing a dihydroxy compound containing at least a dihydroxy compound having at least one bonding structure -CH2-O- within the molecule to react with a carbonic acid diester in the presence of a polymerization catalyst.

[0043]

[0044] Here, as the dihydroxy compound having the bonding structure represented by the structural formula (1), any compound having 2 alcoholic hydroxyl groups, containing a structure having a linking group -CH2-O- within the molecule, and capable of reacting with a carbonic acid diester in the presence of a polymerization catalyst to produce a polycarbonate can be used, and a plurality of types thereof can be used in combination. Further, as the dihydroxy compound used in the polycarbonate resin of the present application, a dihydroxy compound not having the bonding structure represented by the structural formula (1) can also be used in combination. Hereinafter, the dihydroxy compound having the bonding structure represented by the structural formula (1) will be sometimes simply referred to as dihydroxy compound (A), and the dihydroxy compound not having the bonding structure represented by the structural formula (1) will be sometimes simply referred to as dihydroxy compound (B).

[0045] (Dihydroxy Compound (A))

[0046] The "linking group -CH2-O-" in the dihydroxy compound (A) means a structure in which atoms other than hydrogen atoms are mutually bonded to constitute a molecule. In this linking group, as an atom which can be bonded to at least an oxygen atom or an atom which can be bonded to both a carbon atom and an oxygen atom, 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.

[0047] More specifically, as the dihydroxy compound (A), there can be mentioned, for example, a compound 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, 2,2-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;4,4'-bis(2-hydroxyethoxy)phenyl sulfide, 4,4'-bis[4-(2-dihydroxyethoxy)-3- methylphenyl]sulfide, 4,4'-bis(2-hydroxyethoxyphenyl) sulfoxide, 4,4'-bis[4-(2- dihydroxyethoxy)-3-methylphenyl]sulfoxide, 4,4'-bis(2-hydroxyethoxyphenyl) sulfone, 4,4'-bis[4-(2-dihydroxyethoxy)-3-methylphenyl]sulfone, 1,4- dihydroxyethoxybenzene, 1,3-dihydroxyethoxybenzene, 1,2- dihydroxyethoxybenzene, 1,3-bis[2-[4-(2-hydroxyethoxy)phenyl]propyl]benzene, 1,4- bis[2-[4-(2-hydroxyethoxy)phenyl]propyl]benzene, 4,4'-bis(2- hydroxyethoxy)biphenyl, 1,3-bis[4-(2-hydroxyethoxy)phenyl]-5,7-dimethyladamantane, a dihydroxy compound represented by the following formula (4) of an anhydrous sugar alcohol; and a compound having a cyclic ether structure such as a spiroglycol represented by the following general formula (6) can be used alone or in combination with two or more kinds thereof.

[0048]

[0049] These dihydroxy compounds (A) can be used alone or in combination with two or more kinds thereof. In the present application, as the dihydroxy compound represented by the aforementioned formula (4), isosorbide, isomannide, and isoidide in a stereoisomer relationship can be exemplified, and one kind thereof can be used alone or two or more kinds thereof can be used in combination.

[0050] Note that, among the dihydroxy compounds (A), isosorbide obtained by dehydration condensation of sorbitol manufactured from various starches which are abundant as resources and can be easily obtained, is most preferable in terms of easiness of acquisition and manufacture, optical properties, and moldability. In the present application, isosorbide is suitably used as the dihydroxy compound (A).

[0051] (Dihydroxy compound (B))

[0052] In this invention, dihydroxy compound (B) can be used as the dihydroxy compound, which is a dihydroxy compound other than dihydroxy compound (A). As dihydroxy compound (B), for example, alicyclic dihydroxy compounds, aliphatic dihydroxy compounds, oxoalkyl diols, aromatic dihydroxy compounds, and diols having cyclic ether structures can be used as dihydroxy compounds that form structural units of polycarbonate, and can be used together with dihydroxy compound (A) and, for example, dihydroxy compound shown in formula (4).

[0053] The alicyclic dihydroxy compound used in this invention is not particularly limited, but compounds typically containing a five-membered or six-membered ring structure are preferred. Furthermore, the six-membered ring structure can be fixed into a chair or boat shape by covalent bonds. By making the alicyclic dihydroxy compound a five- or six-membered ring structure, the heat resistance of the resulting polycarbonate can be improved. The alicyclic dihydroxy compound typically contains 70 or less carbon atoms, preferably 50 or less, and more preferably 30 or less. A higher number of carbon atoms results in higher heat resistance, but makes it difficult to synthesize or purify, or increases costs. A smaller number of carbon atoms makes it easier to purify and obtain.

[0054] As alicyclic dihydroxy compounds containing a five-membered ring structure or a six-membered ring structure that can be used in this invention, specifically, alicyclic dihydroxy compounds represented by the following general formula (II) or (III) can be listed.

[0055] HOCH2-R 1 -CH2OH (II)

[0056] HO-R 2 -OH (III)

[0057] In equations (II) and (III), R 1 R 2 These represent cycloalkylene groups with 4 to 20 carbon atoms, respectively.

[0058] Regarding cyclohexanediethanol, which is an alicyclic dihydroxy compound represented by the above general formula (II), including R in general formula (II) 1 Using the following general formula (IIa) (where R is...) 3 Various isomers (represented by alkyl groups or hydrogen atoms with 1 to 12 carbon atoms) are listed. Specific examples of such isomers include 1,2-cyclohexanediethanol, 1,3-cyclohexanediethanol, and 1,4-cyclohexanediethanol.

[0059]

[0060] Regarding tricyclodecanediethanol and pentacyclopentadecanedimethanol, which are alicyclic dihydroxy compounds represented by the above general formula (II), including R in general formula (II)1 various isomers represented by the following general formula (IIb) (in the formula, n represents 0 or 1).

[0061]

[0062] As the alicyclic dihydric compound represented by the above general formula (II), 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 2-methyl-1,4-cyclohexanediol, etc. are included. 1 various isomers represented by the following general formula (IIc) (in the formula, m represents 0 or 1). As such isomers, specifically, 2,6-decahydronaphthalene dimethanol, 1,5-decahydronaphthalene dimethanol, 2,3-decahydronaphthalene dimethanol, etc. can be mentioned.

[0063]

[0064] As the alicyclic dihydric compound represented by the above general formula (II), 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 2-methyl-1,4-cyclohexanediol, etc. are included. 1 various isomers represented by the following general formula (IIc) (in the formula, m represents 0 or 1). As such isomers, specifically, 2,6-decahydronaphthalene dimethanol, 1,5-decahydronaphthalene dimethanol, 2,3-decahydronaphthalene dimethanol, etc. can be mentioned.

[0065]

[0066] As the alicyclic dihydric compound represented by the above general formula (II), 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 2-methyl-1,4-cyclohexanediol, etc. are included. 1 various isomers represented by the following general formula (IIc) (in the formula, m represents 0 or 1). As such isomers, specifically, 2,6-decahydronaphthalene dimethanol, 1,5-decahydronaphthalene dimethanol, 2,3-decahydronaphthalene dimethanol, etc. can be mentioned.

[0067]

[0068] As the alicyclic dihydric compound represented by the above general formula (II), 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 2-methyl-1,4-cyclohexanediol, etc. are included. 2 various isomers represented by the following general formula (IIIa) (in the formula, R 3 represents an alkyl group having 1 to 12 carbon atoms or a hydrogen atom). As such isomers, specifically, 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 2-methyl-1,4-cyclohexanediol, etc. can be mentioned.

[0069]

[0070] As the alicyclic dihydric compound represented by the above general formula (II), 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 2-methyl-1,4-cyclohexanediol, etc. are included. 2 various isomers represented by the following general formula (IIIb) (in the formula, n represents 0 or 1).

[0071]

[0072] As the alicyclic dihydric compound represented by the above general formula (III), decalin diol or tricyclodecane diol, including R in general formula (III), can be used. 2 As the alicyclic dihydric compound represented by the above general formula (III), decalin diol or tricyclodecane diol, including R in general formula (III), can be used.

[0073]

[0074] As the alicyclic dihydric compound represented by the above general formula (III), decalin diol or tricyclodecane diol, including R in general formula (III), can be used. 2 As the alicyclic dihydric compound represented by the above general formula (III), decalin diol or tricyclodecane diol, including R in general formula (III), can be used.

[0075]

[0076] As the alicyclic dihydric compound represented by the above general formula (III), decalin diol or tricyclodecane diol, including R in general formula (III), can be used. 2 As the alicyclic dihydric compound represented by the above general formula (III), decalin diol or tricyclodecane diol, including R in general formula (III), can be used.

[0077]

[0078] Among the specific examples of the alicyclic dihydric compound, particularly preferable are cyclohexane dimethanol, tricyclodecane dimethanol, adamantane diol, pentacyclopentadecane dimethanol, and from the viewpoints of easiness of acquisition and easiness of handling, preferable are 1,4-cyclohexane dimethanol, 1,3-cyclohexane dimethanol, 1,2-cyclohexane dimethanol, and tricyclodecane dimethanol. In the present application, as the dihydric compound (B), tricyclodecane dimethanol is suitably used.

[0079] As the aliphatic dihydric compound which can be used in the present application, for example, ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 1,5-heptanediol, 1,6-hexanediol can be exemplified. As the oxyalkylene glycol which can be used in the present application, for example, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol can be exemplified.

[0080] As the aromatic dihydroxy compound usable in the present application, 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-hydroxyphenyl)pentane, 1,1-bis(4-hydroxyphenyl)cyclohexane, bis(4-hydroxyphenyl)sulfone, 2,4'-dihydroxydiphenylsulfone, bis(4-hydroxyphenyl)sulfide, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3,3'-dichlorodiphenyl ether, 4,4'-dihydroxy-2,5-diethoxydiphenyl ether, 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy-2-methyl)phenyl]fluorene, 9,9-bis(4-hydroxyphenyl)fluorene, 9,9-bis(4-hydroxy-2-methylphenyl)fluorene can be exemplified.

[0081] As the diol having a cyclic ether structure usable in the present application, for example, spirodiols, dioxane diols can be exemplified. Note that the above exemplified compounds are examples of the alicyclic dihydroxy compound, the aliphatic dihydroxy compound, the oxyalkylene diol, the aromatic dihydroxy compound, the diol having a cyclic ether structure usable in the present application, but are not limited at all thereto. One or two or more of these compounds can be used together with the dihydroxy compound represented by formula (4).

[0082] By using these dihydroxy compounds (B), effects of improving the softness in accordance with the use, improving the heat resistance, improving the moldability, and the like can be obtained. The proportion of the dihydroxy compound (A), for example, the dihydroxy compound represented by formula (4), to the total dihydroxy compound constituting the polycarbonate resin of the present application is not particularly limited, and is preferably 10 mol% or more, more preferably 40 mol% or more, further preferably 60 mol% or more, and is preferably 90 mol% or less, more preferably 80 mol% or less, further preferably 70 mol% or less. If the proportion of the structural unit derived from the other dihydroxy compound is too much, the performance such as optical properties can sometimes be reduced.

[0083] Among the above other dihydroxy compounds, when an alicyclic dihydroxy compound is used, the proportion of the total of the dihydroxy compound (A), for example, the dihydroxy compound represented by formula (4), and the alicyclic dihydroxy compound, with respect to the total dihydroxy compound constituting the polycarbonate is not particularly limited, and is preferably 80 mol% or more, more preferably 90 mol% or more, and further preferably 95 mol% or more.

[0084] Further, regarding the proportion of the structural unit derived from the dihydroxy compound (A), for example, the dihydroxy compound represented by formula (4), and the structural unit derived from the alicyclic dihydroxy compound in the polycarbonate resin of the present application, these can be selected at an arbitrary ratio, and the proportion of the structural unit derived from the dihydroxy compound represented by formula (4) : the structural unit derived from the alicyclic dihydroxy compound = 1 : 99 to 99 : 1 (mol%) is preferred, and the proportion of the structural unit derived from the dihydroxy compound represented by formula (4) : the structural unit derived from the alicyclic dihydroxy compound = 10 : 90 to 90 : 10 (mol%) is particularly preferred. If the proportion of the structural unit derived from the dihydroxy compound represented by formula (4) is higher and the proportion of the structural unit derived from the alicyclic dihydroxy compound is lower than the above range, there is a tendency that coloring is easy, and conversely, if the proportion of the structural unit derived from the dihydroxy compound represented by formula (4) is lower and the proportion of the structural unit derived from the alicyclic dihydroxy compound is higher than the above range, there is a tendency that the molecular weight is difficult to increase.

[0085] Further, when an aliphatic dihydroxy compound, an oxyalkylene glycol, an aromatic dihydroxy compound, or a diol having a cyclic ether structure is used, the proportion of the total of the dihydroxy compound (A), for example, the dihydroxy compound represented by formula (4), and these various dihydroxy compounds, with respect to the total dihydroxy compound constituting the polycarbonate is not particularly limited, and can be selected at an arbitrary ratio. Further, the proportion of the structural unit derived from the dihydroxy compound (A), for example, the dihydroxy compound represented by formula (4), and the structural unit derived from these various dihydroxy compounds is also not particularly limited, and can be selected at an arbitrary ratio.

[0086] Details of the polycarbonate-based resin are described in, for example, Japanese Patent Application Publication No. 2012-31370 (Japanese Patent No. 5448264). The description of this patent document is incorporated herein by reference.

[0087] C. Method for manufacturing optical film

[0088] The optical film is obtained by film-forming a resin such as the polycarbonate-based resin described in item B. As the method of forming the film, any and appropriate molding process can be used. As specific examples, there can be mentioned compression molding, transfer molding, injection molding, extrusion molding, blow molding, powder molding, FRP molding, flow coating (e.g., flow casting), calender molding, hot pressing, and the like. Among them, extrusion molding or flow coating, which can improve the smoothness of the resulting film and can obtain good optical uniformity, is preferred. In the flow coating, problems can occur due to residual solvent, and therefore extrusion molding is particularly preferred, and melt extrusion molding using a T-die is preferred from the viewpoint of film productivity. The molding conditions can be appropriately set depending on the composition, kind, and properties desired as an optical film of the resin used.

[0089] D. Polarizing plate

[0090] The optical film described in items A to C above can be provided in the form of a laminate thereof with other optical films and / or optical members. In one embodiment, the optical film can be provided in the form of a laminate thereof with a polarizing member (typically, a polarizing plate). Thus, the present application includes a polarizing plate having the above-described optical film.

[0091] Typically, the polarizing plate has a polarizing member and the above-described optical film attached to at least one surface of the polarizing member by means of an adhesive layer. In the polarizing member, a protective layer can be provided on at least one surface of the polarizing member. Further, an adhesive layer and a spacer can be provided on the surface of the polarizing plate opposite to the observation side.

[0092] In one embodiment, the polarizing plate has an irregularly shaped processed portion. By providing the polarizing plate with the above-described optical film, a polarizing plate having good irregularly shaped processability can be obtained. In the present specification, the "irregularly shaped processed portion" refers to a portion processed into a special shape different from a general shape (e.g., a rectangular shape, a chamfered corner). As representative examples of the irregularly shaped processed portion, there can be mentioned a through-hole, and a cutting processed portion which becomes a recess when viewed from the top. As representative examples of the recess, there can be mentioned a shape approximating a boat shape, a V-shaped notch, and a U-shaped notch. Further, the polarizing plate can be irregularly shaped as a whole. As such an example, there can be mentioned a shape corresponding to the instrument panel of an automobile, as shown in Figure 1 and Figure 2 As representative examples of the irregularly shaped processed portion, there can be mentioned a through-hole, and a cutting processed portion which becomes a recess when viewed from the top. As representative examples of the recess, there can be mentioned a shape approximating a boat shape, a V-shaped notch, and a U-shaped notch. Further, the polarizing plate can be irregularly shaped as a whole. As such an example, there can be mentioned a shape corresponding to the instrument panel of an automobile, as shown in Figure 3 and Figure 4 As representative examples of the irregularly shaped processed portion, there can be mentioned a through-hole, and a cutting processed portion which becomes a recess when viewed from the top. As representative examples of the recess, there can be mentioned a shape approximating a boat shape, a V-shaped notch, and a U-shaped notch. Further, the polarizing plate can be irregularly shaped as a whole. As such an example, there can be mentioned a shape corresponding to the instrument panel of an automobile, as shown in

[0093] As the polarizing member, any and appropriate polarizing member can be used. For example, the resin film forming the polarizing member can be a single-layer resin film or a laminate of two or more layers.

[0094] As a specific example of the polarizing member composed of a single-layer resin film, there can be mentioned a polarizing member obtained by dyeing treatment using iodine, a dichroic dye or the like, and stretching treatment, for a hydrophilic polymer film such as a polyvinyl alcohol (PVA)-based film, a partially formaldehyde- condensed PVA-based film, an ethylene-vinyl acetate copolymer-based partially saponified film or the like. From the aspect of excellent optical properties, a polarizing member obtained by dyeing a PVA-based film with iodine and uniaxially stretching the same is preferably used.

[0095] The above-described dyeing with iodine is performed by, for example, immersing a PVA-based film in an aqueous iodine solution. The stretching ratio of the above-described uniaxial stretching is preferably 3 to 7 times. The stretching can be performed after the dyeing treatment or can be performed while dyeing. Further, the dyeing can be performed again after stretching. As needed, the PVA-based film is subjected to swelling treatment, crosslinking treatment, cleaning treatment, drying treatment or the like. For example, by washing the PVA-based film with water before dyeing, not only dirt or an anti-blocking agent on the surface of the PVA-based film but also the PVA-based film is allowed to swell to prevent uneven dyeing.

[0096] As a specific example of the polarizing member obtained using a laminate, there can be mentioned a polarizing member obtained using a laminate of a resin base material and a PVA-based resin layer (PVA-based resin film) laminated to the resin base material, or a laminate of a resin base material and a PVA-based resin layer formed by coating the resin base material. Details of a manufacturing method of such a polarizing member are described in, for example, Japanese Patent Application Publication No. 2012-73580 (Japanese Patent No. 5414738) and the like. The description of this patent document is incorporated herein by reference. The entire description of this publication is incorporated herein by reference.

[0097] In one embodiment, the thickness of the polarizing member is preferably 1 μm to 25 μm, more preferably 3 μm to 10 μm, and further preferably 3 μm to 8 μm. If the thickness of the polarizing member is in this range, warping at the time of heating can be favorably suppressed and good appearance durability at the time of heating can be obtained.

[0098] The protective layer is formed of any and suitable protective film used as a thin film for protecting the polarizing member. As specific examples of the material that is the main component of the protective film, there are cellulose-based resins such as triacetyl cellulose (TAC), polyester-based, polyvinyl alcohol-based, polycarbonate-based, polyamide-based, polyimide-based, polyethersulfone-based, polysulfone-based, polystyrene-based, polynorbornene-based, polyolefin-based, (meth)acrylic-based, acetate-based, and other transparent resins. In addition, there are thermosetting resins such as (meth)acrylic-based, urethane-based, (meth)acrylic urethane-based, epoxy-based, silicone-based, and ultraviolet-curing resins. In addition to these, there are vitreous polymers such as silicone-based polymers. In addition, a polymer film described in Japanese Patent Application Publication No. 2001-343529 (WO 01 / 37007) can also be used. As the material of the film, a resin composition containing, for example, a thermoplastic resin having a side chain with a substituted or unsubstituted imide group and a thermoplastic resin having a side chain with a substituted or unsubstituted phenyl group and a nitrile group can be used, and a resin composition having, for example, an alternating copolymer formed of isobutylene and N-methyl maleimide and an acrylonitrile-styrene copolymer can be cited. The polymer film can be, for example, an extrusion molded product of the above-described resin composition.

[0099] The thickness of the protective layer is preferably 10 μm to 100 μm. The protective layer can be laminated to the polarizing member with the aid of an adhesive layer (specifically, an adhesive layer, a binder layer), or can be laminated to the polarizing member in close contact (without the aid of an adhesive layer). As needed, a surface treatment layer such as a hard coat layer, an anti-glare layer, and an anti-reflection layer can be formed on the protective layer disposed on the outermost surface of the polarizing plate with a phase difference layer.

[0100] As the binder that forms the binder layer, any and suitable binder can be used. As the base resin of the binder, there are, for example, acrylic-based resins, styrene-based resins, silicone-based resins, urethane-based resins, and rubber-based resins. Such base resins are described in, for example, Japanese Patent Application Publication No. 2015-120337 (Japanese Patent No. 6457789) or Japanese Patent Application Publication No. 2011-201983. The descriptions of these publications are incorporated by reference in the present specification. As the crosslinking agent that can be contained in the binder, there are, for example, isocyanate compounds, epoxy compounds, and aziridine compounds. The binder can contain, for example, a silane coupling agent. The compounding recipe of the binder can be appropriately set according to the target and desired properties.

[0101] The storage modulus of the binder layer is preferably 1.0 x 10 4 Pa to 1.0 x 10 7 Pa, and more preferably 2.0 x 10 4 Pa to 5.0 x 10 6Pa. If the storage modulus of the adhesive layer is in this range, the blocking at the time of winding can be suppressed. Note that the storage modulus can be obtained from, for example, dynamic viscoelasticity measurement at a temperature of 23°C and an angular velocity of 0.1 rad / s.

[0102] The thickness of the adhesive layer is preferably 1 μm to 60 μm, more preferably 3 μm to 30 μm. If the thickness is too thin, the adhesion can sometimes be insufficient, and bubbles or the like can enter the adhesive interface. If the thickness is too thick, the adhesive can easily be squeezed out, and the like.

[0103] In practice, during the period until the optical film is actually used, a separator is temporarily attached to the surface of the adhesive layer in a peelable manner. By providing the separator, the surface protection film can be wound into a roll while the adhesive layer is protected. As the separator, a plastic (for example, polyethylene terephthalate (PET), polyethylene, polypropylene) film, nonwoven fabric, or paper, and the like, which has been surface-coated with a peeling agent such as a silicone-based peeling agent, a fluorine-based peeling agent, an acrylic long-chain alkyl ester-based peeling agent, and the like, can be cited. The thickness of the separator can be any and appropriate thickness according to the purpose. The thickness of the separator is, for example, 10 μm to 100 μm.

[0104] Example

[0105] Hereinafter, the present application will be specifically described by way of examples, but the present application is not limited to these examples. Note that the measurement method and evaluation method of each property are as shown below.

[0106] (1) In-Plane Phase Difference and Wavelength Dispersion Property

[0107] The optical film obtained in the examples and comparative examples was cut into a length of 4 cm and a width of 4 cm, and used as a measurement sample. With respect to this measurement sample, the in-plane phase difference Re(550) was measured using an article manufactured by Axometrics, Inc., product name "Axoscan". Furthermore, Re(450) was also measured, and Re(450) / Re(550) was calculated.

[0108] (2) Thickness

[0109] The thickness of 10 μm or less was measured using an interference film thickness meter (manufactured by Otsuka Electronics Co., Ltd., product name "MCPD-3000"). The thickness exceeding 10 μm was measured using a digital micrometer (manufactured by ANRITSU, product name "KC-351C").

[0110] (3) Moisture Permeability

[0111] With respect to the optical film obtained in the examples and comparative examples, the moisture permeability test (cup method) according to JIS Z0208 was performed, and the moisture permeability was measured in an atmosphere of a temperature of 40°C and a humidity of 92% RH, over an area of 1 m2 The amount of water vapor (g) of the sample.

[0112] (4) Phase difference change

[0113] The optical films obtained in the examples and comparative examples were cut into 5 cm x 5 cm, and an adhesive was attached to one side using a hand roller 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 (humidity test), and the phase difference change (%) before and after the test was calculated.

[0114] (5) Puncture modulus

[0115] The puncture modulus of the optical films obtained in the examples and comparative examples was calculated by dividing the force (gf) at which the optical film was broken (or ruptured) by the strain (mm) at that time when a needle (puncture jig) was vertically punctured with respect to the main surface of the optical film. As the needle, a needle having a front end diameter of 1 mmφ, 0.5R was used. The puncture speed of the needle was set to 0.33 cm / sec. The measurement was performed in an environment at a temperature of 23°C.

[0116] (6) Puncture strength

[0117] A tester equipped with a needle having a front end diameter of 1 mmφ, 0.5R was used. The optical films obtained in the examples and comparative examples were clamped with two jigs having a circular hole in the center, and the optical films were fixed to the tester. The needle was vertically lowered with respect to the optical film in such a manner that the needle passed through the hole of the jig, and the strength at which the optical film was broken was measured. Regarding the test conditions, the puncture speed was set to 0.33 cm / sec in an environment at a temperature of 23±3°C. The puncture test was performed on 12 test pieces, and the puncture strength per unit film thickness of the optical film was calculated by dividing the average value thereof by the thickness of the optical film.

[0118] (7) Breaking strength and breaking elongation

[0119] After the optical films obtained in the examples and comparative examples were cut into 1 cm wide x 13 cm long, an "Autograph ASG-50D" (manufactured by Shimadzu Corporation) was used as a tensile tester, and a tensile test was performed at a tensile speed of 200 mm / min, a distance between chucks of 50 mm, and a room temperature (23°C) to calculate the stress at which the optical film was broken as the breaking strength and the strain (elongation) at which the optical film was broken as the breaking strength.

[0120] (8) Adhesiveness

[0121] The optical film obtained in the examples and comparative examples was bonded to a polarizing member to obtain a laminate. The obtained laminate was cut to a size of 200 mm in a direction parallel to the stretching direction of the polarizing member and 15 mm in a direction orthogonal thereto, and the laminate was bonded to a glass plate. Further, a notch was made between the optical film and the polarizing member with a cutter, and the optical film and the polarizing member were peeled at a peeling speed of 1000 mm / min in a 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 evaluated as good, and when the peeling strength was less than 1 N / 15 mm, it was evaluated as poor.

[0122] (9) Handling (Evaluation of Process Defects During Handling)

[0123] When the optical film obtained in the examples and comparative examples was handled at a speed of 5 m / min to 40 m / min using a guide roll, it was evaluated as good if no defects such as bending, scratches, and impact marks were generated (if it could be handled without problems), and it was evaluated as poor if defects such as bending, scratches, and impact marks were generated.

[0124] (10) Flexibility (MIT Test)

[0125] The MIT test was performed in accordance with JIS P 8115. Specifically, the optical film obtained in the examples and comparative examples was cut to a length of 15 cm and a width of 1.5 cm, and used as a measurement sample. The measurement sample was installed in an MIT folding fatigue tester BE-202 type (manufactured by TESTER Industries Co., Ltd.) (load: 1.0 kgf, R of jig: 0.38 mm), and repeatedly folded under conditions of a test speed of 90 cpm and a folding angle of 90°, and the number of folds at which the measurement sample broke was used as a test value. When the test value was 500 or more, it was evaluated as good, and when the test value was less than 500, it was evaluated as poor.

[0126] (11) Evaluation of Bright Spot When Pressed

[0127] The same sample as that evaluated in the puncture strength test was bonded to a polarizing member, and the film side was pressed with a force of 10 gf / μm using a puncture tester. Thereafter, one polarizing plate was prepared in a manner such that the axis was 90° to the polarizing plate, and transmitted light was made to pass through the opposite side of the film on which the puncture test was performed in a crossed prism state, and when no bright spot was observed, it was evaluated as good, and when a bright spot was observed, it was evaluated as poor.

[0128] (12) Irregular Shape Processability Test

[0129] A 3-kW CO2laser was irradiated to the optical film obtained in the examples and comparative examples, and cutting was performed in the flow direction of the film and in the direction perpendicular to the flow direction to obtain a 200 mm x 200 mm test sample. The cut portion was observed using a laser microscope, and was rated as good if no cracks were generated, and as poor if cracks were generated and / or cutting was not possible.

[0130] (13) Crack resistance

[0131] The optical film obtained in the examples and comparative examples was subjected to a thermal shock test of -40°C to 80°C for 300 cycles, and was rated as good if no cracks of 300 μm or more were generated, and as poor if cracks of 300 μm or more were generated.

[0132] [Example 1]

[0133] 1. Production of optical film

[0134] In a reaction vessel, 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 0.979 parts by mass of a 0.2% by mass aqueous cesium carbonate solution as a catalyst were charged, and a heating bath temperature was raised to 150°C under a nitrogen atmosphere as a procedure of the first stage of the reaction while stirring as necessary to dissolve the raw materials (about 15 minutes). Next, the pressure was set to 13.3 kPa from the normal pressure, and the heating bath temperature was raised to 190°C over 1 hour while the generated phenol was taken out to the outside of the reaction vessel. After the entire reaction vessel was maintained at 190°C for 15 minutes, the pressure in the reaction vessel was set to 6.67 kPa as a procedure of the second stage, and the heating bath temperature was raised to 230°C over 15 minutes, and the generated phenol was taken out to the outside of the reaction vessel. Since the stirring torque of the stirrer gradually increased, the temperature was raised to 250°C over 8 minutes, and further, the pressure in the reaction vessel was reduced to 0.200 kPa or less in order to remove the generated phenol. After the prescribed stirring torque was reached, the reaction was ended, and the generated reaction product was extruded into water to obtain a polycarbonate resin pellet. After the obtained polycarbonate resin was vacuum-dried at 80°C for 5 hours, an optical film composed of the polycarbonate resin was produced using a film production device provided with a single-screw extruder (Toshiba Machine Co., Ltd., barrel set temperature: 250°C), a T die (width: 300 mm, set temperature: 250°C), a cooling roll (set temperature: 120 to 130°C), and a winding machine. The obtained optical film had a wavelength dispersion value of 1.02, an in-plane retardation Re(550) of 2 nm, a thickness of 13 μm, a moisture permeability of 156 g / m 2• 24h, the phase difference change was 0.08%. Further, the puncture modulus of the optical film was 153 gf / mm, the puncture strength was 25 gf / μm, the breaking strength was 2614 MPa, and the breaking elongation was 6.3%. The obtained optical film was subjected to the evaluation of (8) to (13) described above. The results are shown in Table 1.

[0135] [Example 2]

[0136] An optical film composed of a polycarbonate resin was prepared with a thickness of 20 μm, and otherwise the same operation as in Example 1 was performed. The wavelength dispersion value of the obtained optical film was 1.02, the in-plane phase difference Re(550) was 3 nm, the moisture permeability was 113 g / m 2 • 24h, the phase difference change was 0.07%. Further, the puncture modulus of the optical film was 200 gf / mm, the puncture strength was 26 gf / μm, the breaking strength was 2614 MPa, and the breaking elongation was 6.3%. The obtained optical film was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0137] [Example 3]

[0138] An optical film composed of a polycarbonate resin was prepared with a thickness of 25 μm, and otherwise the same operation as in Example 1 was performed. The wavelength dispersion value of the obtained optical film was 1.02, the in-plane phase difference Re(550) was 2 nm, the moisture permeability was 102 g / m 2 • 24h, the phase difference change was 0.07%. Further, the puncture modulus of the optical film was 264 gf / mm, the puncture strength was 23.6 gf / μm, the breaking strength was 2614 MPa, and the breaking elongation was 6.3%. The obtained optical film was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0139] [Comparative Example 1]

[0140] As the resin film, a commercially available cycloolefin resin film (ZEONOR, manufactured by ZEON Corporation) was used. The wavelength dispersion value of the optical film was 1.01, the in-plane phase difference Re(550) was 2 nm, the thickness was 25 μm, and the moisture permeability was 10 g / m 2 • 24h, the phase difference change was 0.6%. Further, the puncture modulus of the optical film was 304 gf / mm, the puncture strength was 17 gf / μm, the breaking strength was 2150 MPa, and the breaking elongation was 0.7%. The obtained optical film was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0141] [Comparative Example 2]

[0142] A triacetyl cellulose (TAC) film (KONICA MINOLTA Co., Ltd., trade name "KC2UA") was used. The wavelength dispersion value of the optical film was 1.09, the in-plane retardation Re(550) was 3 nm, the thickness was 25 μm, and the moisture permeability was 320 g / m 2 • 24 h, the retardation change was 2%. Further, the puncture modulus of the optical film was 480 gf / mm, the puncture strength was 22 gf / μm, the breaking strength was 4200 MPa, and the breaking elongation was 8%. The obtained optical film was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0143] [Comparative Example 3]

[0144] The thickness of the optical film was set to 5 μm, and otherwise the same operation as in Example 1 was performed to obtain an optical film. The wavelength dispersion value of the obtained optical film was 1.02, the in-plane retardation Re(550) was 0.8 nm, and the moisture permeability was 172 g / m 2 • 24 h, the retardation change was 1%. Further, the puncture modulus of the optical film was 65 gf / mm, the puncture strength was 20 gf / μm, the breaking strength was 1200 MPa, and the breaking elongation was 5.5%. The obtained optical film was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0145] [Table 1]

[0146]

[0147] As is clear from Table 1, the adhesiveness, handleability, bendability, suppression of occurrence of bright spots at the time of pressing, irregular shape processability, and crack resistance of the optical film of the examples of the present application were all excellent. It is presumed that this was achieved by using an optical film containing a specific polycarbonate resin, and setting the puncture modulus, the puncture strength per unit film thickness, the breaking strength, and the breaking elongation of the optical film to be within specific ranges.

[0148] Industrial applicability

[0149] The optical film and the polarizing plate of the embodiments of the present application can be suitably used for image display devices.

Claims

1. An optical film comprising a polycarbonate resin, wherein the in-plane phase difference Re(550) of the optical film is 2 nm or more and 10 nm or less, Re(450) / Re(550) is 0.98 to 1.03, the puncture modulus is 100 gf / mm or more, the thickness is 20 μm or less, and the absolute value of the rate of change of the in-plane phase difference Re(550) of the optical film after 500 hours at a temperature of 65°C and a humidity of 90% is 1% or less.

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

3. The optical thin film according to claim 1 or 2 has a tensile strength of 800 MPa or more and a tensile elongation of 3% or more.

4. A polarizing plate comprising a polarizing element and an optical film according to any one of claims 1 to 3, the optical film being adhered to at least one side of the polarizing element by means of an adhesive layer.

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