KR20220029385A - Optical film and polarizing plate - Google Patents

Abstract

Provided is an optical film which suppresses the occurrence of a process defect during conveyance, suppresses the occurrence of a bright spot during press-fitting of a film, and also has excellent flexibility, release processability, and crack resistance. The optical film which comprises a specific polycarbonate-based resin and has an in-plane retardation Re (550) of 10 nm or less, Re (450)/Re (550) of 0.98 to 1.03, and a rotor elastic modulus of 50 gf/mm or more is used.

Description

Optical film and polarizer {OPTICAL FILM AND POLARIZING PLATE}

The present invention relates to an optical film and a polarizing plate.

Recently, there has been a demand for thinning devices having liquid crystal screens, such as TVs and smartphones. In order to implement|achieve the thickness reduction of a device, various thin films are proposed. However, in a thin film, process defects, such as a wrinkle during conveyance of a film, a wrinkle, and a dent, may generate|occur|produce. In addition, there are cases where a bright spot is generated during press-fitting of the film, and the flexibility, mold release workability, crack resistance, and the like are insufficient in some cases.

Japanese Patent No. 3325560 Publication

The present invention has been made in order to solve the above conventional problems, and the object thereof is that the occurrence of process defects during conveyance is suppressed, the occurrence of bright spots during press-fitting of the film is suppressed, and the flexibility, mold release workability and It is to provide the optical film excellent in crack resistance.

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

In one embodiment, the puncture strength per unit film thickness of the said optical film is 10 gf/micrometer or more.

In one embodiment, the breaking strength of the said optical film is 800 MPa or more, Moreover, breaking elongation is 3 % or more.

In one embodiment, the thickness of the said optical film is 25 micrometers or less.

In one embodiment, the absolute value of the rate of change of the in-plane retardation Re (550) after 500 hours has passed under the conditions of the temperature of 65 degreeC of the said optical film, and 90% of humidity conditions is 1 % or less.

In another embodiment of the present invention, a polarizing plate is provided. The polarizing plate includes a polarizer and the optical film bonded to at least one side of the polarizer via an adhesive layer.

ADVANTAGE OF THE INVENTION According to embodiment of this invention, generation|occurrence|production of the process defect during conveyance is suppressed and the optical film excellent in flexibility can be implement|achieved by containing a specific polycarbonate-type resin and making the puncture modulus into a specific range. In addition, by setting the puncture strength, breaking strength, and breaking elongation per unit film thickness within specific ranges, the occurrence of bright spots during press-fitting of the film is suppressed, and an optical film excellent in releasability and crack resistance can be realized.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic plan view explaining an example of the mold release or mold release part in the polarizing plate by embodiment of this invention.
It is a schematic plan view explaining the modification of the mold release or mold release part in the polarizing plate by embodiment of this invention.
3 is a schematic plan view for explaining a further modified example of a mold release or a mold release processing portion in a polarizing plate according to an embodiment of the present invention.
4 is a schematic plan view for explaining a further modified example of a mold release or a mold release processing portion in a polarizing plate according to an embodiment of the present invention.

EMBODIMENT OF THE INVENTION Hereinafter, although embodiment of this invention is described, this invention is not limited to these embodiment.

(Definition of terms and symbols)

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 in which the in-plane refractive index is maximum (ie, slow axis direction), "ny" is the refractive index in the direction orthogonal to the slow axis in the plane (ie, fast axis direction), and "nz" is It is the refractive index in the thickness direction.

(2) In-plane phase difference (Re)

"Re(λ)" is the in-plane retardation measured with the light of wavelength λnm in 23 degreeC. For example, "Re(550)" is the in-plane retardation measured with the light of wavelength 550nm in 23 degreeC. Re(λ) is obtained by the formula: Re(λ)=(nx-ny)×d when the thickness of the layer (film) is d(nm).

A. Optical Film

The optical film according to an embodiment of the present invention contains a polycarbonate resin. The optical film by embodiment of this invention is a polycarbonate resin film typically.

The in-plane retardation Re(550) of the 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 may be, for example, 0 nm.

The optical film exhibits a flat wavelength dispersion characteristic in which the retardation value hardly changes depending on the wavelength of the measurement light. Re(450)/Re(550) of an optical film is 0.98-1.03, Preferably it is 0.99-1.03, More preferably, it is 1.00-1.03. By using such a polycarbonate-based resin having Re(450)/Re(550), excellent antireflection properties can be realized.

The optical film has a puncture modulus of 50 gf/mm or more, preferably 100 gf/mm or more, and more preferably 150 gf/mm or more. The puncture modulus is obtained by dividing the force (gf) immediately before the film breaks (or torn) by the deformation (mm) at that time when the needle (piercing jig) is cut perpendicularly to the main surface of the film. When the optical film has the puncture modulus as described above, the occurrence of process defects during transport and the like can be suppressed, and an optical film excellent in flexibility can be obtained.

The puncture strength per unit film thickness of the optical film is preferably 10 gf/μm or more, more preferably 15 gf/μm or more, and still more preferably 20 gf/μm or more. The puncture strength per unit film thickness refers to the strength when the film is broken by dropping the needle vertically with respect to the film divided by the thickness. When the film has the puncture strength per unit film thickness as described above, the occurrence of bright spots during press-fitting of the film is suppressed, and an optical film excellent in releasability can be obtained.

The breaking strength of the optical film is preferably 800 MPa or more, and the breaking elongation is preferably 3% or more. The breaking strength of an optical film becomes like this. More preferably, it is 1500 MPa or more, More preferably, it is 2500 MPa or more. The upper limit of the breaking strength of an optical film is 70000 MPa, for example. Moreover, the breaking elongation of an optical film becomes like this. More preferably, it is 4 % or more, More preferably, it is 6 % or more. The upper limit of the elongation at break of the optical film may be, for example, 300%. Breaking strength refers to the stress when the film breaks in a tensile test. Elongation at break represents the strain (elongation rate) when the film is broken. When the breaking strength and breaking elongation of the optical film are within the above ranges, an optical film having excellent crack resistance can be obtained.

The thickness of the said optical film becomes like this. Preferably it is 25 micrometers or less, More preferably, it is 20 micrometers or less. The lower limit of the thickness of the optical film may be, for example, 0.5 μm. When the thickness of an optical film is such a range, an optical film can be applied suitably to a thin device.

The absolute value of the change rate of the in-plane retardation Re (550) after 500 hours has elapsed under the conditions of a temperature of 65 ° C. and a humidity of 90% in the optical film is preferably 1% or less, more preferably 0.5% or less, and further Preferably it is 0.1% or less. The lower limit of the absolute value of the change rate may be, for example, 0.01%. The phase difference change rate is represented by |(Re ₅₀₀ -Re ₀ )/Re ₀ |×100 (%). Re ₀ is the in-plane retardation (nm) of the optical film before the start of the test, and Re ₅₀₀ is the in-plane retardation (nm) of the optical film after the test. Since the absolute value of the rate of change of the in-plane retardation Re (550) of the optical film is within this range, when the optical film is applied to an image display device, the color change due to the phase difference at each location on the image display device is reduced, so color unevenness on the display occurrence can be suppressed.

The water vapor transmission rate of the said optical film becomes like this. Preferably it is 300 g/m<2>*24h or less, More preferably, it is 200 g/m<2>*24h or less, More preferably, it is 160 g/m2*24h or less. The lower limit of the moisture permeability may be, for example, 1 g/m 2 ·24h. If the water vapor transmission rate of an optical film is such a range, the change of the phase difference in a humidified environment can be suppressed.

The absolute value of the photoelastic coefficient of the optical film is preferably 2×10 ^-11 m2/N or less, more preferably 2.0×10 ^-13 m2/N to 1.5×10 ^-11 m2/N, still more preferably Usually 1.0×10 ^-12 m2/N to 1.2×10 ^-11 m2/N. When the absolute value of the photoelastic modulus of the optical film is within such a range, it is difficult to produce a phase difference change when a shrinkage stress at the time of heating occurs. As a result, when an optical film is applied to an image display apparatus, thermal nonuniformity of an image display apparatus can be prevented favorably.

According to the embodiment of the present invention, as described above, the desired in-plane retardation, wavelength dispersion characteristics and thickness are satisfied, and the occurrence of process defects during transport is suppressed, and the occurrence of bright spots at the time of press-fitting of the film is suppressed, An optical film excellent in flexibility, mold release processability and crack resistance can be obtained. Such an optical film, for example, is thin and can be suitably used for a bendable and/or foldable EL display device.

B. Construction Materials

As mentioned above, an optical film is a resin film containing polycarbonate resin typically.

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 contains at least one bonding structure -CH ₂ -O- in the molecule It is produced by reacting a dihydroxy compound containing at least a dihydroxy compound having a dihydroxy compound and a diester carbonate in the presence of a polymerization catalyst.

Here, the dihydroxy compound having a bonding structure represented by the structural formula (1) includes a structure having two alcoholic hydroxyl groups and a linking group -CH ₂ -O- in the molecule, and in the presence of a polymerization catalyst, If it is a compound which reacts with diester carbonate and can produce|generate a polycarbonate, even if it is a compound of any structure, it is possible to use it, and it does not matter even if it uses multiple types together. Moreover, as a dihydroxy compound used for the polycarbonate resin which concerns on this invention, you may use together the dihydroxy compound which does not have the bonding structure represented by Structural formula (1). Hereinafter, the dihydroxy compound having the bonding structure represented by Structural Formula (1) is referred to as the dihydroxy compound (A), and the dihydroxy compound not having the bonding structure represented by the Structural Formula (1) is referred to as the dihydroxy compound (B). may be abbreviated as

(dihydroxy compound (A))

The "linking group -CH ₂ -O-" in the dihydroxy compound (A) means a structure in which it bonds to atoms other than a hydrogen atom to form a molecule. In this coupling group, at least as an atom to which an oxygen atom can bond or an atom to which a carbon atom and an oxygen atom can bond simultaneously, a carbon atom is most preferable. The number of "linking groups -CH ₂ -O-" in the dihydroxy compound (A) is preferably 1 or more, more preferably 2 to 4.

More specifically, as the dihydroxy compound (A), for example, 9,9-bis(4-(2-hydroxyethoxy)phenyl)fluorene, 9,9-bis(4-(2-hydroxyl) Roxyethoxy)-3-methylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-isopropylphenyl)fluorene, 9,9-bis(4-(2-hydroxy) Roxyethoxy)-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 A compound having an aromatic group in a side chain and an ether group bonded to an aromatic group in the main chain, as exemplified by ,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-hydroxyethane) Toxy)-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- Methyl pentane, 2,2-bis[4-(2-hydroxyethoxy)phenyl]octane, 1,1-bis[4-(2-hydroxyethane) Toxy)phenyl]decane, 2,2-bis[3-bromo-4-(2-hydroxyethoxy)phenyl]propane, 2,2-bis[3-cyclohexyl-4-(2-hydroxyethane) Bis(hydroxyalkoxyaryl)alkanes, 1,1-bis[4-(2-hydroxyethoxy)phenyl]cyclohexane, 1,1-bis[3- as exemplified by oxy)phenyl]propane bis(hydroxyalkoxyaryl) as exemplified by cyclohexyl-4-(2-hydroxyethoxy)phenyl]cyclohexane, 1,1-bis[4-(2-hydroxyethoxy)phenyl]cyclopentane ) cycloalkanes, 4,4'-bis(2-hydroxyethoxy)diphenyl ether, and 4,4'-bis(2-hydroxyethoxy)-3,3'-dimethyldiphenyl ether As such, dihydroxyalkoxydiaryl ethers, 4,4'-bis(2-hydroxyethoxyphenyl)sulfide, 4,4'-bis[4-(2-dihydroxyethoxy)-3 Bishydroxyalkoxyarylsulfides, 4,4'-bis(2-hydroxyethoxyphenyl)sulfoxide, 4,4'-bis[4-(2-) as exemplified by -methylphenyl]sulfide bishydroxyalkoxyarylsulfoxides, as exemplified by dihydroxyethoxy)-3-methylphenyl]sulfoxide, 4,4'-bis(2-hydroxyethoxyphenyl)sulfone, 4,4'- bis[4-(2-dihydroxyethoxy)-3-methylphenyl]sulfone, bishydroxyalkoxyarylsulfones, 1,4-bishydroxyethoxybenzene, 1,3-bishydrone Roxyethoxybenzene, 1,2-bishydroxyethoxybenzene, 1,3-bis[2-[4-(2-hydroxyethoxy)phenyl]propyl]benzene, 1,4-bis[2-[ 4-(2-hydroxyethoxy)phenyl]propyl]benzene, 4,4'-bis(2-hydroxyethoxy)biphenyl, 1,3-bis[4-(2-hydroxyethoxy)phenyl ]-5,7-dimethyladamantane, anhydrous sugar alcohols represented by dihydroxy compounds represented by the following formula (4), and spiroglycol represented by the following formula (6), compounds having a cyclic ether structure These are mentioned, These may be used independently and may be used in combination of 2 or more type.

These dihydroxy compounds (A) may be used independently and may be used in combination of 2 or more type. In the present invention, examples of the dihydroxy compound represented by the formula (4) include isosorbide, isomannide, and isoidet, which have a stereoisomer relationship, and these compounds may be used alone It is good, and you may use it in combination of 2 or more type.

In addition, among the dihydroxy compounds (A), isosorbide obtained by dehydration condensation of sorbitol produced from various starches, which is abundantly present as a resource and is readily available, is easy to obtain and manufacture, optical properties, and moldability. most preferred from In this invention, isosorbide is used suitably as a dihydroxy compound (A).

(dihydroxy compound (B))

In the present invention, as the dihydroxy compound, a dihydroxy compound (B) which is a dihydroxy compound other than the dihydroxy compound (A) may be used. As the dihydroxy compound (B), for example, an alicyclic dihydroxy compound, an aliphatic dihydroxy compound, an oxyalkylene glycol, an aromatic dihydroxy compound, or a diol having a cyclic ether structure is used in the composition of the polycarbonate. As a dihydroxy compound used as a unit, it can be used together with a dihydroxy compound (A), for example, the dihydroxy compound represented by Formula (4).

Although it does not specifically limit as an alicyclic dihydroxy compound which can be used for this invention, Preferably, the compound containing a 5-membered ring structure or a 6-membered ring structure is used normally. In addition, the 6-membered ring structure may be fixed in a chair shape or an embryo shape by a covalent bond. When the alicyclic dihydroxy compound has a 5-membered ring or 6-membered ring structure, the heat resistance of the obtained polycarbonate can be increased. The number of carbon atoms contained in the alicyclic dihydroxy compound is usually 70 or less, preferably 50 or less, and more preferably 30 or less. Although heat resistance becomes high, so that this value becomes large, synthesis|combination becomes difficult, refinement|purification becomes difficult, or cost becomes expensive. It becomes easy to refine|purify and it becomes easy to obtain, so that the number of carbon atoms becomes small.

Specific examples of the alicyclic dihydroxy compound having a 5-membered ring structure or a 6-membered ring structure that can be used in the present invention include an alicyclic dihydroxy compound represented by the following general formula (II) or (III). there is.

HOCH ₂ -R ¹ -CH ₂ OH (II)

HO-R ² -OH (III)

(In formulas (II) and (III), R ¹ and R ² each represent a cycloalkylene group having 4 to 20 carbon atoms.)

As cyclohexanedimethanol which is an alicyclic dihydroxy compound represented by the said general formula (II), in general formula (II), R< ¹ > is following general formula (IIa) (wherein, R< ³ > is C1-C12) represents an alkyl group or a hydrogen atom of)). Specific examples of such substances include 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, and 1,4-cyclohexanedimethanol.

As tricyclodecanedimethanol and pentacyclopentadecanedimethanol which are alicyclic dihydroxy compounds represented by the general formula (II), in the general formula (II), R ¹ is the following general formula (IIb) (wherein , n represents 0 or 1.).

As decalindimethanol or tricyclotetradecanedimethanol which is an alicyclic dihydroxy compound represented by the general formula (II), in the general formula (II), R ¹ is the following general formula (IIc) (wherein, m represents 0 or 1.) and includes various isomers. Specific examples of such substances include 2,6-decalin dimethanol, 1,5-decalin dimethanol, and 2,3-decalin dimethanol.

Moreover, as norbornein dimethanol which is an alicyclic dihydroxy compound represented by the said general formula (II), in general formula (II), R< ¹ > includes various isomers represented by the following general formula (IId). . Specific examples of such substances include 2,3-norbornein dimethanol and 2,5-norbornein dimethanol.

As adamantane dimethanol which is an alicyclic dihydroxy compound represented by general formula (II), in general formula (II), R< ¹ > includes various isomers represented by the following general formula (IIe). Specific examples of this include 1,3-adamantane dimethanol and the like.

Moreover, in the cyclohexanediol which is an alicyclic dihydroxy compound represented by the said general formula (III), in general formula (III), R< ² > is the following general formula (IIIa) (wherein, R< ³ > is C1-C10) 12 is an alkyl group or a hydrogen atom.) Specific examples of such substances include 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 2-methyl-1,4-cyclohexanediol, and the like.

As tricyclodecanediol and pentacyclopentadecanediol, which are alicyclic dihydroxy compounds represented by the general formula (III), in the general formula (III), R ² is the following general formula (IIIb) (wherein n represents 0 or 1.).

As decalindiol or tricyclotetradecanediol which is an alicyclic dihydroxy compound represented by the general formula (III), in the general formula (III), R ² is the following general formula (IIIc) (wherein m is 0) , or 1 is represented.) As such, 2,6-decalindiol, 1,5-decalindiol, 2,3-decalindiol, etc. are specifically used.

As norborneindiol which is an alicyclic dihydroxy compound represented by the said general formula (III), in general formula (III), R< ² > includes various isomers represented by the following general formula (IIId). As such, 2,3-norborneindiol, 2,5-norborneindiol, etc. are specifically used.

As adamantanediol which is an alicyclic dihydroxy compound represented by the said general formula (III), in general formula (III), R< ² > includes various isomers represented by the following general formula (IIIe). As such, 1,3-adamantanediol or the like is specifically used.

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

Examples of the aliphatic dihydroxy compound usable 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 are mentioned. Examples of the oxyalkylene glycols usable in the present invention include diethylene glycol, triethylene glycol, tetraethylene glycol, and polyethylene glycol.

Examples of the aromatic dihydroxy compound usable in the present invention include 2,2-bis(4-hydroxyphenyl)propane [=bisphenol A], 2,2-bis(4-hydroxy-3,5). -dimethylphenyl)propane, 2,2-bis(4-hydroxy-3,5-diethylphenyl)propane, 2,2-bis(4-hydroxy-(3,5-diphenyl)phenyl)propane, 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane, 2,2-bis(4-hydroxyphenyl)pentane, 2,4'-dihydroxy-diphenylmethane, bis (4-hydroxyphenyl)methane, bis(4-hydroxy-5-nitrophenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 3,3-bis(4-hydroxyphenyl)pentane , 1,1-bis (4-hydroxyphenyl) cyclohexane, bis (4-hydroxyphenyl) sulfone, 2,4'-dihydroxydiphenyl sulfone, 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 are mentioned.

Examples of the diols having a cyclic ether structure that can be used in the present invention include spiroglycols and dioxane glycols. In addition, the above exemplary compound is an example of an alicyclic dihydroxy compound, an aliphatic dihydroxy compound, an oxyalkylene glycol, an aromatic dihydroxy compound, and a diol having a cyclic ether structure that can be used in the present invention. It is not limited to these. These compounds can be used 1 type, or 2 or more types together with the dihydroxy compound represented by Formula (4).

By using these dihydroxy compounds (B), effects such as improvement of flexibility, improvement of heat resistance, and improvement of moldability according to the use can be obtained. The ratio of the dihydroxy compound (A), for example, the dihydroxy compound represented by the formula (4) to the total dihydroxy compounds constituting the polycarbonate resin according to the present invention is not particularly limited, but preferably is 10 mol% or more, more preferably 40 mol% or more, still more preferably 60 mol% or more, preferably 90 mol% or less, more preferably 80 mol% or less, still more preferably 70 mol% or less. . When there is too much content rate of the structural unit derived from another dihydroxy compound, performance, such as an optical characteristic, may fall.

Among the other dihydroxy compounds, when an alicyclic dihydroxy compound is used, the dihydroxy compound (A) relative to all the dihydroxy compounds constituting the polycarbonate, for example, the dihydroxy compound represented by the formula (4) Although the ratio of the total of a hydroxy compound and an alicyclic dihydroxy compound is not specifically limited, Preferably it is 80 mol% or more, More preferably, it is 90 mol% or more, More preferably, it is 95 mol% or more.

Further, in the polycarbonate resin according to the present invention, the dihydroxy compound (A), for example, a structural unit derived from a dihydroxy compound represented by formula (4) and an alicyclic dihydroxy compound derived from The content ratio of the structural unit can be selected at any ratio, but 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 preferable, and in particular, structural unit derived from the dihydroxy compound represented by formula (4): structural unit derived from an alicyclic dihydroxy compound = 10:90 to 90:10 (mol%) ) is preferred. If there are more structural units derived from the dihydroxy compound represented by formula (4) than the above range and fewer constitutional units derived from the alicyclic dihydroxy compound, coloration becomes easier, and conversely, the dihydroxy compound represented by formula (4) When the number of structural units derived from the hydroxy compound is small and the number of structural units derived from the alicyclic dihydroxy compound is large, the molecular weight tends to be difficult to increase.

In addition, when an aliphatic dihydroxy compound, oxyalkylene glycol, aromatic dihydroxy compound, or diol having a cyclic ether structure is used, the dihydroxy compound (A) relative to all the dihydroxy compounds constituting the polycarbonate , For example, the ratio of the sum total of the dihydroxy compound represented by Formula (4) and each dihydroxy compound of these is not specifically limited, It can select by arbitrary ratios. In addition, the content ratio of the structural unit derived from the dihydroxy compound (A), for example, the dihydroxy compound represented by Formula (4), and the structural units derived from each of these dihydroxy compounds is not particularly limited. and may be selected at any ratio.

The detail of polycarbonate-type resin is described in Unexamined-Japanese-Patent No. 2012-31370 (Japanese Patent No. 5448264), for example. The description of the said patent document is taken in here as a reference.

C. Method of Manufacturing Optical Film

An optical film is obtained, for example by film-molding resin, such as polycarbonate-type resin of B item. As a method for forming the film, any suitable molding processing method may be employed. Specific examples include a compression molding method, a transfer molding method, an injection molding method, an extrusion molding method, a blow molding method, a powder molding method, an FRP molding method, a cast coating method (for example, a casting method), a calender molding method, a hot press method, and the like. Among these, the extrusion molding method or the cast coating method which can improve the smoothness of the film obtained and can obtain favorable optical uniformity is preferable. In the cast coating method, since there is a risk of problems caused by residual solvents, extrusion molding is particularly preferred, and particularly, melt extrusion molding using a T-die is preferred from the viewpoint of film productivity. Molding conditions can be suitably set according to the composition and kind of resin used, characteristics desired as an optical film, etc.

D. Polarizer

The optical film according to the above items A to C may be provided as a laminate with other optical films and/or optical members. In one embodiment, the optical film may be provided as a laminate (typically, a polarizing plate) with a polarizer. Accordingly, the present invention includes a polarizing plate having the optical film.

A polarizing plate typically has a polarizer and the said optical film bonded to at least single side|surface of the said polarizer via an adhesive bond layer. In the said polarizer, you may have a protective layer on at least single side|surface of a polarizer. Moreover, you may have an adhesive layer and a separator in the surface on the opposite side to the visual recognition side of the said polarizing plate.

In one embodiment, a polarizing plate has a mold release process part. When a polarizing plate has the said optical film, the polarizing plate which has favorable mold release processability can be obtained. As used herein, the term "deformation processing part" refers to a part processed into a special shape different from a general shape (eg, a rectangle, chamfering a corner part). As shown in Figs. 1 and 2, representative examples of the mold-releasing part include a through hole and a cutting part that becomes a concave part in a plan view. Representative examples of the concave portion include a shape approximate to a pear shape, a V-shaped notch, and a U-shaped notch. In addition, the whole polarizing plate may be mold-releasingly processed. As such an example, as shown in FIG. 3 and FIG. 4, the shape corresponding to the meter panel of an automobile is mentioned. The shape includes a portion in which the outer edge is formed in an arc shape along the rotational direction of the meter needle, and the outer edge forms a V-shape (including an R shape) convex inward in the plane direction. The mold-releasing portion is formed at any suitable position depending on the purpose.

As the polarizer, any suitable polarizer may be employed. For example, a single-layered resin film may be sufficient as the resin film which forms a polarizer, and the laminated body of two or more layers may be sufficient as it.

As a specific example of a polarizer composed of a single-layer resin film, a polyvinyl alcohol (PVA)-based film, a partially formalized PVA-based film, and a hydrophilic polymer film such as an ethylene/vinyl acetate copolymer-based partially saponified film, iodine, dichroic dye, etc. polyene-based oriented films such as those subjected to the dyeing treatment and stretching treatment with a dichroic substance of PVA and dehydrochloric acid treatment products of PVA and polyvinyl chloride. Preferably, since it is excellent in an optical characteristic, the polarizer obtained by dyeing a PVA-type film with iodine and carrying out uniaxial stretching is used.

The dyeing with the iodine is performed, for example, by immersing the PVA-based film in an aqueous iodine solution. The draw ratio of the said uniaxial stretching becomes like this. Preferably it is 3 to 7 times. Extending|stretching may be performed after a dyeing process, and may be performed, dyeing|staining. Moreover, you may dye|dye after extending|stretching. A swelling process, a crosslinking process, a washing process, a drying process, etc. are given to a PVA-type film as needed. For example, by immersing the PVA-based film in water and washing with water before dyeing, it is possible to not only wash the surface of the PVA-based film from stains and anti-blocking agents, but also to swell the PVA-based film to prevent uneven coloring.

As a specific example of a polarizer obtained using a laminate, a laminate of a resin substrate and a PVA-based resin layer (PVA-based resin film) laminated on the resin substrate, or a resin substrate and a PVA-based resin layer coated on the resin substrate. The polarizer obtained using a laminated body is mentioned. The detail of the manufacturing method of such a polarizer is described in Unexamined-Japanese-Patent No. 2012-73580 (Japanese Patent No. 5414738) etc., for example. The description of the above patent document is incorporated herein by reference. The above publication is incorporated herein by reference in its entirety.

In one embodiment, the thickness of a polarizer becomes like this. Preferably they are 1 micrometer - 25 micrometers, More preferably, they are 3 micrometers - 10 micrometers, More preferably, they are 3 micrometers - 8 micrometers. Curl|Karl at the time of a heating can be suppressed favorably as the thickness of a polarizer is such a range, and favorable external appearance durability at the time of a heating is acquired.

The protective layer is formed of any suitable protective film that can be used as a film for protecting the polarizer. Specific examples of the material used as the main component of the protective film include cellulose resins such as triacetyl cellulose (TAC), polyester, polyvinyl alcohol, polycarbonate, polyamide, polyimide, and polyethersulfone. and transparent resins such as polysulfone-based, polystyrene-based, polynorbornene-based, polyolefin-based, (meth)acrylic-based and acetate-based resins. Moreover, thermosetting resins, such as (meth)acrylic type, a urethane type, (meth)acryl urethane type, an epoxy type, silicone type, or ultraviolet curable resin etc. are mentioned. In addition, for example, glassy polymers, such as a siloxane type polymer, are mentioned. Moreover, the polymer film described in Unexamined-Japanese-Patent No. 2001-343529 (WO01/37007) can also be used. As a material for this film, for example, a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in a side chain and a thermoplastic resin having a substituted or unsubstituted phenyl group and a nitrile group in the side chain can be used, for example, , a resin composition comprising an alternating copolymer composed of isobutene and N-methylmaleimide and an acrylonitrile/styrene copolymer. The polymer film may be, for example, an extrusion molding of the resin composition.

The thickness of the protective layer is preferably 10 µm to 100 µm. The protective layer may be laminated on the polarizer via an adhesive layer (specifically, an adhesive layer, an adhesive layer), or may be laminated on the polarizer in close contact (without interposing an adhesive layer). Surface treatment layers, such as a hard-coat layer, a glare-proof layer, and an antireflection layer, may be formed in the protective layer arrange|positioned at the outermost surface of a polarizing plate with a retardation layer as needed.

As the pressure-sensitive adhesive for forming the pressure-sensitive adhesive layer, any suitable pressure-sensitive adhesive may be employed. As base resin of an adhesive, an acrylic resin, a styrene resin, a silicone resin, a urethane resin, and a rubber resin are mentioned, for example. Such a base resin is described in, for example, Japanese Patent Application Laid-Open No. 2015-120337 (Japanese Patent No. 6457789) or Japanese Patent Application Laid-Open No. 2011-201983. The description of these publications is incorporated herein by reference. As a crosslinking agent which can be contained in an adhesive, an isocyanate compound, an epoxy compound, and an aziridine compound are mentioned, for example. The pressure-sensitive adhesive may contain, for example, a silane coupling agent. The formulation of the pressure-sensitive adhesive may be appropriately set according to the purpose and desired characteristics.

The storage modulus of the pressure-sensitive adhesive layer is preferably 1.0×10 ⁴ Pa to 1.0×10 ⁷ Pa, more preferably 2.0×10 ⁴ Pa to 5.0×10 ⁶ Pa. Blocking at the time of roll formation can be suppressed as the storage modulus of an adhesive layer is this range. In addition, the storage modulus can be calculated|required from the dynamic viscoelasticity measurement at a temperature of 23 degreeC and angular velocity of 0.1 rad/s, for example.

The thickness of an adhesive layer becomes like this. Preferably they are 1 micrometer - 60 micrometers, More preferably, they are 3 micrometers - 30 micrometers. When thickness is too thin, adhesiveness will become inadequate, and a bubble etc. may enter into an adhesive interface. When thickness is too thick, it will become easy to produce defects, such as an adhesive protruding.

Practically, while an optical film is actually used, a separator is temporarily affixed on the surface of an adhesive layer so that peeling is possible. By providing a separator, while protecting an adhesive layer, it becomes possible to wind up a surface protection film in roll shape. As the separator, for example, a plastic (e.g., polyethylene terephthalate (PET), polyethylene, polypropylene) film, nonwoven fabric or paper coated with a release agent such as a silicone-based release agent, a fluorine-based release agent, or a long-chain alkyl acrylate-based release agent. and the like. Any appropriate thickness can be employ|adopted for the thickness of a separator according to the objective. The thickness of the separator is, for example, 10 µm to 100 µm.

(Example)

Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited by these Examples. In addition, the measuring method and evaluation method of each characteristic are as follows.

(1) In-plane retardation and wavelength dispersion characteristics

The optical film obtained by the Example and the comparative example was cut out to 4 cm in length and 4 cm in width, and it was set as the measurement sample. About the said measurement sample, the in-plane retardation Re (550) was measured using the Axometrics company make and product name "Axoscan". Moreover, Re(450) was also measured, and Re(450)/Re(550) was computed.

(2) thickness

The thickness of 10 µm or less was measured using an interference film thickness meter (manufactured by Otsuka Denshi Corporation, product name “MCPD-3000”). The thickness exceeding 10 µm was measured using a digital micrometer (manufactured by Anritsu Corporation, product name “KC-351C”).

(3) moisture permeability

About the optical film obtained in the Example and the comparative example, based on the water vapor transmission rate test (cup method) of JIS Z0208, in the atmosphere of a temperature of 40 degreeC, and a humidity of 92%RH, the amount of water vapor passing through the sample of 1 m2 area in 24 hours (g) ) was measured.

(4) Phase difference change

The optical film obtained in the Example and the comparative example was cut out to 5 cm x 5 cm, the adhesive was affixed on one side with a hand roller, the adhesive side was affixed on the single side|surface of alkali glass, and the test piece was obtained. The test piece was stored in an oven at a temperature of 65°C and a humidity of 90% for 500 hours (humidification test), and the phase difference change (%) before the start of the test and after the test was calculated.

(5) stony elastic modulus

The puncture elastic modulus is the force (gf) just before the optical film obtained in Examples and Comparative Examples is broken (or torn) when the needle (piercing jig) is pierced perpendicularly to the main surface of the optical film. It was obtained by dividing by the strain (mm). As the needle, one having a tip diameter of 1 mmφ and 0.5R was used. The needle piercing speed was set to 0.33 cm/sec. The said measurement was performed in the environment of the temperature of 23 degreeC.

(6) piercing strength

A testing machine equipped with a needle having a tip diameter of 1 mmφ and 0.5R was used. The optical films obtained in Examples and Comparative Examples were sandwiched by two jigs with a circular hole in the center, and the optical film was fixed to the testing machine. The needle was vertically lowered with respect to the optical film so as to pass through the hole of the jig, and the strength when the optical film was broken was measured. The test conditions were made into 0.33 cm/sec of puncture velocity in the environment of the temperature of 23±3 degreeC. The puncture test was performed about 12 tests, and the puncture strength per unit film thickness of the optical film was calculated|required by dividing the average value by the thickness of the optical film.

(7) Breaking strength and breaking elongation

After cutting the optical films obtained in Examples and Comparative Examples to be 1 cm in width x 13 cm in length, "Autograph ASG-50D type" (manufactured by Shimadzu Corporation) was used as a tensile tester, and a tensile rate of 200 mm/min. , a tensile test was performed at a distance between chucks of 50 mm and room temperature (23 ° C.), the stress when the optical film was broken was determined as the breaking strength, and the strain (elongation) when the optical film was broken was determined as the breaking strength.

(8) Adhesiveness

The optical film and the polarizer obtained by the Example and the comparative example were bonded together, and the laminated body was obtained. The obtained laminated body was cut out in the magnitude|size of 200 mm in parallel to the extending|stretching direction of a polarizer, and 15 mm in an orthogonal direction, and the said laminated body was bonded to the glass plate. Then, an incision is made between the optical film and the polarizer with a cutter knife, and the optical film and the polarizer are peeled off at a peeling rate of 1000 mm / min in a 90 degree direction by the Tenshiron universal testing machine RTC (manufactured by A&D Corporation), The peel strength (N/15 mm) was measured. The case where the peeling strength was 1N/15mm or more was considered good, and the case where it was less than 1N/15mm was made into bad.

(9) Runability (evaluation of process defects at the time of conveyance)

When conveying the optical film obtained in an Example and a comparative example at a speed of 5 m/min to 40 m/min by a guide roll, if there is no occurrence of defects such as creases, scratches, and dents (if it can be conveyed without problems), good, bending , it was set as defective when a wound, a dent, etc. generate|occur|produced.

(10) Flexibility (MIT test)

The MIT test was performed based on JIS P 8115. Specifically, the optical film obtained by the Example and the comparative example was cut out to 15 cm in length and 1.5 cm in width, and it was set as the measurement sample. Attach the measurement sample to the MIT bending fatigue tester BE-202 (manufactured by Tester Sangyo Co., Ltd.) (load 1.0 kgf, clamp R: 0.38 mm), and bend repeatedly at a test speed of 90 cpm and a bending angle of 90 °, The number of times of bending when the measurement sample fracture|ruptures was made into the test value. The thing of 500 or more times of an experience value was made into favorable, and the thing of less than 500 times was made defective.

(11) Evaluation of bright spots at the time of press-fitting

The same sample as the sample evaluated in the puncture strength test was adhered to the polarizer, and the film side was pushed with a force of 10 gf/μm in the puncture tester. Thereafter, one polarizing plate was prepared so as to form an axis of 90° with the polarizing plate, and transmitted light was transmitted from the opposite side of the tested film in the state of cross nicol.

(12) Releasability test

The optical film obtained in Examples and Comparative Examples was irradiated with a CO ₂ laser at an energy of 3Kw, cut in a direction perpendicular to the flow direction and flow direction of the film, and a measurement sample of 200 mm × 200 mm was obtained. The cut part was observed using the laser microscope, and when a crack enters and/or cannot be cut, it was set as good, if a crack did not enter it.

(13) crack resistance

After 300 cycles of the optical films obtained in Examples and Comparative Examples were subjected to a heat shock test at -40°C to 80°C, good when no cracks of 300 μm or more were generated, and poor when cracks of 300 μm or more were generated. did it with

[Example 1]

1. Fabrication of optical film

To 81.98 parts by mass of isosorbide (hereinafter sometimes abbreviated as "ISB"), 47.19 parts by mass of tricyclodecanedimethanol (hereinafter sometimes abbreviated as "TCDDM"), diphenyl carbonate (hereinafter, "DPC") 175.1 parts by mass, and 0.979 parts by mass of a 0.2 mass % cesium carbonate aqueous solution as a catalyst are put into a reaction vessel, and in a nitrogen atmosphere, as the first step of the reaction, the heating tank temperature is set to 150 ° C. The raw material was dissolved by heating and stirring if necessary (about 15 minutes). Then, the phenol generated was taken out of the reaction vessel while the pressure was set to 13.3 kPa from normal pressure and the temperature of the heating tank was raised to 190° C. in 1 hour. After maintaining the entire reaction vessel at 190° C. for 15 minutes, as the second step, the pressure in the reaction vessel is set to 6.67 kPa, the heating tank temperature is raised to 230° C. for 15 minutes, and the generated phenol is removed from the reaction vessel. pulled out Since the stirring torque of the stirrer increased, the temperature was raised to 250°C in 8 minutes, and the pressure in the reaction vessel was reached to 0.200 kPa or less in order to remove the generated phenol. After reaching a predetermined stirring torque, the reaction was terminated, and the resulting reactant was extruded into water to obtain polycarbonate resin pellets. After vacuum drying the obtained polycarbonate resin at 80 ° C. for 5 hours, a single screw extruder (manufactured by Toshiba Kikai, cylinder set temperature: 250 ° C), T-die (width 300 mm, set temperature: 250 ° C), chill roll (set The optical film comprised from polycarbonate resin was produced using the film film forming apparatus provided with temperature: 120-130 degreeC) and the winder. 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 water vapor transmission rate of 156 g/m 2 ·24 h, and a retardation change of 0.08%. In addition, the piercing elastic modulus of the optical film was 153 gf/mm, the piercing strength was 25 gf/㎛, the breaking strength was 2614 MPa, and the breaking elongation was 6.3%. The obtained optical film was used for evaluation of said (8)-(13). A result is shown in Table 1.

[Example 2]

Except having made the thickness of the optical film comprised from polycarbonate resin into 20 micrometers, it carried out similarly to Example 1, and obtained the optical film. The obtained optical film had a wavelength dispersion value of 1.02, an in-plane retardation Re(550) of 3 nm, a water vapor transmission rate of 113 g/m 2 ·24h, and a phase difference change of 0.07%. In addition, the puncture modulus of the optical film was 200 gf/mm, the piercing strength was 26 gf/㎛, 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. A result is shown in Table 1.

[Example 3]

Except having made the thickness of the optical film comprised from polycarbonate resin into 25 micrometers, it carried out similarly to Example 1, and obtained the optical film. The obtained optical film had a wavelength dispersion value of 1.02, an in-plane retardation Re(550) of 2 nm, a water vapor transmission rate of 102 g/m 2 ·24h, and a phase difference change of 0.07%. In addition, the piercing elastic modulus of the optical film was 264 gf/mm, the piercing strength was 23.6 gf/㎛, 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. A result is shown in Table 1.

[Comparative Example 1]

As the resin film, a commercially available cycloolefin-based resin film (manufactured by Nippon Zeon, trade name “Zeonoa”) was used. The wavelength dispersion value of the optical film was 1.01, the in-plane retardation Re (550) was 2 nm, the thickness was 25 μm, the water vapor transmission rate was 10 g/m 2 ·24h, and the phase difference change was 0.6%. In addition, the piercing elastic modulus of the optical film was 304 gf/mm, the piercing strength was 17 gf/㎛, 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. A result is shown in Table 1.

[Comparative Example 2]

A triacetyl cellulose (TAC) film (manufactured by Konica Minolta, trade name "KC2UA") was used. The optical film had a wavelength dispersion value of 1.09, an in-plane retardation Re (550) of 3 nm, a thickness of 25 μm, a water vapor transmission rate of 320 g/m 2 ·24h, and a phase difference change of 2%. In addition, the piercing elastic modulus of the optical film was 480 gf/mm, the piercing strength was 22 gf/㎛, 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. A result is shown in Table 1.

[Comparative Example 3]

Except having made the thickness of the optical film into 5 micrometers, it carried out similarly to Example 1, and obtained the optical film. The obtained optical film had a wavelength dispersion value of 1.02, an in-plane retardation Re(550) of 0.8 nm, a water vapor transmission rate of 172 g/m 2 ·24h, and a phase difference change of 1%. In addition, the puncture modulus of the optical film was 65 gf/mm, the puncture strength was 20 gf/㎛, 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. A result is shown in Table 1.

As is clear from Table 1, it can be seen that the optical films of Examples of the present invention are excellent in all of adhesiveness, running properties, flexibility, suppression of occurrence of bright spots during press-fitting, mold release workability, and crack resistance. It is conjectured that this is realized by using an optical film containing a specific polycarbonate resin, and setting the puncture modulus of the optical film, the puncture strength per unit film thickness, the breaking strength, and the breaking elongation all within specific ranges.

The optical film and polarizing plate by embodiment of this invention are used suitably for an image display apparatus.

Claims (6)

An optical film comprising a polycarbonate resin, having an in-plane retardation Re (550) of 10 nm or less, Re (450)/Re (550) of 0.98 to 1.03, and a puncture modulus of 50 gf/mm or more. The method of claim 1,
An optical film having a puncture strength of 10 gf/㎛ or more per unit film thickness. The method of claim 1,
An optical film having a breaking strength of 800 MPa or more, and a breaking elongation of 3% or more. The method of claim 1,
An optical film having a thickness of 25 μm or less. The method of claim 1,
An optical film having an absolute value of 1% or less of the change rate of the in-plane retardation Re (550) after 500 hours at a temperature of 65° C. and a humidity of 90%. A polarizing plate comprising a polarizer and the optical film according to any one of claims 1 to 5 bonded to at least one side of the polarizer through an adhesive layer.

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