KR102212127B1 - Optical film and polarizer plate comprising the same - Google Patents

Abstract

The present specification relates to an optical film and a polarizing plate including the same.

Description

An optical film and a polarizing plate including the same TECHNICAL FIELD [OPTICAL FILM AND POLARIZER PLATE COMPRISING THE SAME}

The present specification relates to an optical film and a polarizing plate including the same.

A liquid crystal display generally includes an upper substrate on which a common electrode and a color filter are formed, a lower substrate on which a thin film transistor and a pixel electrode, etc. are formed, and a liquid crystal cell positioned between the upper and lower substrates. In the liquid crystal display, an electric field is formed by applying different electric potentials to a pixel electrode and a common electrode, and an arrangement of liquid crystal molecules in a liquid crystal cell is changed by the electric field, thereby adjusting light transmittance to display an image.

As described above, a liquid crystal display device using liquid crystal has advantages such as miniaturization, weight reduction, and low power consumption. However, since the screen is implemented using liquid crystal molecules having anisotropy, the brightness and contrast ratio of the screen vary greatly depending on the viewing angle. Have. In addition, since the light generated from the backlight of the liquid crystal display passes through several paths to reach the viewer's eyes, the amount of light that can be observed by the eyes must be limited to a part of the light emitted from the backlight. As a result, there is a disadvantage that the light utilization efficiency of the backlight unit decreases and the brightness of the screen decreases.

In order to solve the above problems, a method of using a film laminate in which various optical films such as a compensation film and a retardation film are stacked has been proposed. Recently, as these optical films, optical films using a curable liquid crystal are widely used. In the case of such an optical film, a liquid crystal alignment layer for basic alignment of the liquid crystal is required.

In addition, as the demand for an effective wide viewing angle increases with the recent trend of increasing the size of the liquid crystal display device, various alignment methods of the optical film have been studied in order to secure an effective wide viewing angle. One of them is to apply a liquid crystal material on an alignment film and vertically align the liquid crystal material to provide an alignment liquid crystal layer.

In addition to this, in recent years, in accordance with the demand for thinner and lighter liquid crystal display devices, the thickness of the substrate is also becoming thinner. However, when the thickness of the substrate is reduced, the flatness of the surface is also lowered, and thus there is a disadvantage in that the adhesion between the substrate and the alignment liquid crystal layer decreases. Therefore, there is a need for a method capable of improving the adhesion between the substrate and the alignment liquid crystal layer while keeping the thickness of the substrate thin.

Korean Patent Publication 2008-0102806

The present specification is to provide an optical film and a polarizing plate including the same.

This specification is described; An alignment layer in contact with at least one surface of the substrate; And an alignment liquid crystal layer provided on the other surface of a surface in which the substrate of the alignment layer is in contact, wherein the substrate is a cycloolefin polymer film, and the alignment layer is a compound represented by Formula 1 below; And it provides an optical film that is a cured product of a curable composition comprising a hydroxy alkylphenone-based compound.

[Formula 1]

In Formula 1,

a1 and a2 are each an integer of 1 to 6,

When a1 and a2 are each 2 or more, the structures in the two or more parentheses are the same or different from each other,

L1 and L2 are the same as or different from each other, and each independently a substituted or unsubstituted alkylene group; Or a substituted or unsubstituted arylene group,

R1 and R2 are the same as or different from each other, and each independently a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms.

In addition, the present specification is a polarizer; And it provides a polarizing plate including the optical film provided on at least one surface of the polarizer.

In addition, the present specification provides a display panel; And the polarizing plate attached to one or both surfaces of the display panel.

The optical film according to the exemplary embodiment of the present specification may provide a thinner thickness than the conventional one, and may improve adhesion between the substrate and the alignment liquid crystal layer.

1 shows an optical film according to an exemplary embodiment of the present specification.

Hereinafter, the present specification will be described in more detail.

In the present specification, when a part "includes" a certain component, it means that other components may be further included rather than excluding other components unless otherwise stated.

In the present specification, when a member is said to be located "on" another member, this includes not only the case where the member is in contact with the other member, but also the case where another member exists between the two members.

A liquid crystal display generally includes an upper substrate on which a common electrode and a color filter are formed, a lower substrate on which a thin film transistor and a pixel electrode, etc. are formed, and a liquid crystal cell positioned between the upper and lower substrates. In the liquid crystal display, an electric field is formed by applying different electric potentials to a pixel electrode and a common electrode, and an arrangement of liquid crystal molecules in a liquid crystal cell is changed by the electric field, thereby adjusting light transmittance to display an image.

Such a liquid crystal display device is spreading as an optical display device because power consumption is lower than that of a cathode ray tube display, its volume is small, and it is light and easy to carry. In general, a liquid crystal display device has a basic configuration in which polarizing plates are installed on both sides of a liquid crystal cell, and the orientation of the liquid crystal cell changes depending on whether an electric field is applied to the driving circuit, and the characteristics of the transmitted light emitted through the polarizing plate are changed accordingly. Is made visible. In this case, the light path and birefringence change according to the incident angle of the incident light, because the liquid crystal is an anisotropic material having two different refractive indices.

Due to such characteristics, the liquid crystal display device has a contrast ratio, a measure of how clearly an image can be seen, depending on the viewing angle, and gray scale inversion occurs, resulting in poor visibility. It has a drawback. In order to overcome the above disadvantages, an optical retardation film that expresses the optical retardation occurring in a liquid crystal cell or a viewing angle compensation film that optically compensates the viewing angle characteristics generated in the liquid crystal cell is used. .

In addition, various liquid crystal modes are being developed to ensure clear image quality and wide viewing angle of the liquid crystal display, and representatively, Double Domain TN (Twisted Nematic), ASM (Axially Symmetric Aligned Microcell), OCB (optically compensated) blend), vertical alignment (VA), multidomain VA (MVA), surrounding electrode (SE), patterned VA (PVA), in-plane switching (IPS), fringe-field switching (FFS) modes, etc. . Each of these modes has a unique liquid crystal arrangement and has a unique optical anisotropy.

Recently, as these optical films, optical films using a curable liquid crystal are often used. In the case of such an optical film, an alignment layer for basic alignment of the liquid crystal is required. The alignment layer is used for basic alignment of liquid crystals driven in a specific mode, and has been mainly used for alignment of liquid crystals in a liquid crystal cell.

In addition, with the recent trend of increasing the size of the liquid crystal display device, the demand for an effective wide viewing angle is also increasing. In order to secure an effective wide viewing angle, various alignment methods of an optical film have been studied, one of which is to apply a liquid crystal material on an alignment film and vertically align the liquid crystal material to provide an alignment liquid crystal layer.

However, in accordance with the recent demand for thinner and lighter liquid crystal display devices, the thickness of the substrate is also becoming thinner. In particular, in the case of a cycloolefin polymer (COP, cycloolefin polymer) film, the thickness is lowered from 40 μm to 20 μm according to the recent thinning trend. However, when the thickness of the substrate is reduced, the flatness of the surface is also lowered, and thus there is a disadvantage in that the adhesion between the substrate and the alignment liquid crystal layer decreases. Accordingly, there is a need for a method capable of improving the adhesion between the alignment liquid crystal layers while keeping the thickness of the substrate thin.

The optical film according to an exemplary embodiment of the present specification includes an alignment layer formed by curing a curable composition including a compound represented by Formula 1 and a hydroxyalkylphenone compound, thereby improving adhesion between the substrate and the alignment liquid crystal layer. There is an advantage that can be made.

Examples of the substituent in the present specification are described below, but are not limited thereto.

는 연결되는 부위를 의미한다.In this specification,

Means the connected part.

The term "substituted" means that the hydrogen atom bonded to the carbon atom of the compound is replaced with another substituent, and the position to be substituted is not limited as long as the position where the hydrogen atom is substituted, that is, the position where the substituent can be substituted, and when two or more are substituted , Two or more substituents may be the same or different from each other.

In the present specification, the term "substituted or unsubstituted" refers to deuterium; Halogen group; Nitrile group; Hydroxy group; Alkyl group; Cycloalkyl group; Alkenyl group; Aryl group; And N, O, S, Se and Si atoms are substituted with one or more substituents selected from the group consisting of a heterocyclic group containing one or more of the group consisting of two or more substituents of the exemplified substituents are substituted with a connected substituent, or It means not having a substituent.

In the present specification, examples of the halogen group include fluorine, chlorine, bromine, or iodine.

In the present specification, the alkyl group may be linear or branched, and the number of carbon atoms is not particularly limited, but is preferably 1 to 30, more preferably 1 to 20, and most preferably 1 to 10. Specific examples include methyl, ethyl, propyl, n-propyl, isopropyl, butyl, n-butyl, isobutyl, tert-butyl, sec-butyl, 1-methyl-butyl, 1-ethyl-butyl, pentyl, n-pentyl , Isopentyl, neopentyl, tert-pentyl, hexyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, heptyl, n -Heptyl, 1-methylhexyl, cyclopentylmethyl, cyclohexylmethyl, octyl, n-octyl, tert-octyl, 1-methylheptyl, 2-ethylhexyl, 2-propylpentyl, n-nonyl, 2,2-dimethyl Heptyl, 1-ethyl-propyl, 1,1-dimethyl-propyl, isohexyl, 4-methylhexyl, 5-methylhexyl, and the like, but are not limited thereto.

In the present specification, the cycloalkyl group is not particularly limited, but it is preferably 3 to 20 carbon atoms, and more preferably 3 to 10 carbon atoms. Specifically, cyclopropyl, cyclobutyl, cyclopentyl, 3-methylcyclopentyl, 2,3-dimethylcyclopentyl, cyclohexyl, 3-methylcyclohexyl, 4-methylcyclohexyl, 2,3-dimethylcyclohexyl, 3, 4,5-trimethylcyclohexyl, 4-tert-butylcyclohexyl, cycloheptyl, cyclooctyl, and the like, but are not limited thereto.

In the present specification, the alkenyl group may be a straight chain or a branched chain, and the number of carbon atoms is not particularly limited, but it is preferably 2 to 20, and most preferably 2 to 10. Specific examples include vinyl, 1-propenyl, isopropenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 3-methyl-1- Butenyl, 1,3-butadienyl, allyl, 1-phenylvinyl-1-yl, 2-phenylvinyl-1-yl, 2,2-diphenylvinyl-1-yl, 2-phenyl-2-( Naphthyl-1-yl) vinyl-1-yl, 2,2-bis(diphenyl-1-yl) vinyl-1-yl, stilbenyl group, styrenyl group, and the like, but are not limited thereto.

In the present specification, the aryl group is a monocyclic aryl group or a polycyclic aryl group.

In the present specification, when the aryl group is a monocyclic aryl group, the number of carbon atoms is not particularly limited, but it is preferably 6 to 30 carbon atoms, more preferably 6 to 20, and most preferably 6 to 10. Specifically, the monocyclic aryl group may be a phenyl group, a biphenyl group, a terphenyl group, or a quarterphenyl group, but is not limited thereto.

When the aryl group is a polycyclic aryl group, the number of carbon atoms is not particularly limited. It is preferably 10 to 30 carbon atoms, more preferably 10 to 20 carbon atoms, and most preferably 10 to 15 carbon atoms. Specifically, the polycyclic aryl group may be a naphthyl group, an anthracenyl group, a phenanthryl group, a pyrenyl group, a perylenyl group, a chrysenyl group, a fluorenyl group, etc., but is not limited thereto.

In the present specification, the heterocyclic group is one containing at least one of N, O, S, Si and Se as a heteroatom, and the number of carbons is not particularly limited, but it is preferably 2 to 30, and more preferably 2 to 20. And, it is most preferably 2 to 10. Examples of heterocyclic groups include thiophene group, furan group, pyrrole group, imidazole group, thiazole group, oxazole group, oxadiazole group, triazole group, pyridyl group, bipyridyl group, pyrimidyl group, triazine group, acridine group , Pyridazine group, pyrazine group, quinolinyl group, quinazoline group, quinoxalinyl group, phthalazinyl group, pyrido pyrimidine group, pyrido pyrazine group, pyrazino pyrazine group, isoquinoline group, indole group, carbazole group , Benzoxazole group, benzimidazole group, benzothiazole group, benzocarbazole group, benzothiophene group, dibenzothiophene group, benzofuran group, phenanthroline group (phenanthroline), pteridine group (pteridine), thiazolyl group , An isoxazolyl group, an oxadiazolyl group, a thiadiazolyl group, and a dibenzofuran group, but are not limited thereto.

In the present specification, an alkylene group means that the alkyl group has two bonding positions, that is, a divalent group. Except that each of these is a divalent group, the description of the alkyl group described above can be applied.

In the present specification, an arylene group means that the aryl group has two bonding positions, that is, a divalent group. Except that each of these is a divalent group, the description of the aryl group described above may be applied.

This specification is described; An alignment layer in contact with at least one surface of the substrate; And an alignment liquid crystal layer provided on the other surface of a surface in which the substrate of the alignment layer is in contact, wherein the substrate is a cycloolefin polymer film, and the alignment layer is a compound represented by Formula 1 below; And it provides an optical film that is a cured product of a curable composition comprising a hydroxy alkylphenone-based compound.

[Formula 1]

In Formula 1,

a1 and a2 are each an integer of 1 to 6,

When a1 and a2 are each 2 or more, the structures in the two or more parentheses are the same or different from each other,

L1 and L2 are the same as or different from each other, and each independently a substituted or unsubstituted alkylene group; Or a substituted or unsubstituted arylene group,

R1 and R2 are the same as or different from each other, and each independently a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms.

In the present specification, the retardation in the plane direction (Rin), the retardation in the thickness direction (Rth), and the refractive index ratio (Nz) are respectively defined by the following equations (1) to (3).

Equation (1): Rin = (nx-ny) x d

Equation (2): Rth = (nx-nz) x d

Equation (3): Nz = Rth / Rin

In Equations (1) to (3), nx is the refractive index of the axis with the largest refractive index in the plane direction of the plate, ny is the refractive index in the direction perpendicular to nx in the plane direction, and nz is the refractive index in the thickness direction of the plate. And d is the thickness of the plate.

Positive C plates are defined as having a relationship of nx, ny and nz with nx = ny <nz. Films that can be used as the positive C plate include a cycloolefin polymer (COP) film or polycarbonate film, a UV-curable horizontal or horizontally oriented liquid crystal film, polystyrene resin, polyethylene terephthalate. (Polyethylene Terephthalate), and the like, but are not limited thereto.

The negative B plate is defined as having a relationship of nx, ny and nz to nx> ny> nz (Nz> 1.0), and the optical axis of the negative B plate is located between nz and nx. In addition, in the positive B plate, it is defined that nx, ny and nz have a relationship of nz> nx> ny. Films that can be used as the negative B plate or positive B plate include uniaxially stretched triacetyl cellulose (TAC), uniaxially stretched PNB (polynorbonene), biaxially stretched PC (polycarbonate), biaxially stretched COP, and biaxial liquid crystal. Film (biaxial LC film), but is not limited thereto.

In one embodiment of the present specification, it is preferable that the substrate is a cycloolefin polymer film.

In the exemplary embodiment of the present specification, a1 and a2 are each an integer of 1 to 6, and when a1 and a2 are each 2 or more, the structures in the parentheses of 2 or more are the same or different from each other.

In the exemplary embodiment of the present specification, L1 and L2 are the same as or different from each other, and each independently a substituted or unsubstituted alkylene group.

In the exemplary embodiment of the present specification, L1 and L2 are the same as or different from each other, and each independently a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms.

In the exemplary embodiment of the present specification, L1 and L2 are the same as or different from each other, and each independently a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms.

In an exemplary embodiment of the present specification, L1 is a methylene group, an ethylene group, or a propylene group.

In an exemplary embodiment of the present specification, L1 is a methylene group.

In an exemplary embodiment of the present specification, L2 is a methylene group, an ethylene group, or a propylene group.

In an exemplary embodiment of the present specification, L2 is a methylene group.

In the exemplary embodiment of the present specification, R1 and R2 are the same as or different from each other, and each independently a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms.

In the exemplary embodiment of the present specification, R1 is a substituted or unsubstituted methyl group, a substituted or unsubstituted ethyl group, or a substituted or unsubstituted propyl group.

In an exemplary embodiment of the present specification, R1 is a methyl group substituted with an alkenyl group.

In an exemplary embodiment of the present specification, R2 is a substituted or unsubstituted methyl group, a substituted or unsubstituted ethyl group, or a substituted or unsubstituted propyl group.

In an exemplary embodiment of the present specification, R2 is a methyl group substituted with an alkenyl group.

In an exemplary embodiment of the present specification, the compound represented by Formula 1 may be the following compound.

In the exemplary embodiment of the present specification, the curable composition includes a hydroxy alkylphenone-based compound.

The hydroxy alkylphenone-based compound is activated by absorbing a wavelength of 250 nm, and refers to a compound that generates a cation or Lewis acid by irradiation with active energy.

Acrylate-based compounds such as the compound represented by Formula 1 included in the curable composition, specifically, compounds having an aromatic structure, have an absorption wavelength range of 300 nm to 350 nm. Since the hydroxyalkylphenone-based compound and the compound represented by Formula 1 have different absorption wavelength ranges, curing efficiency can be improved compared to compounds having an absorption wavelength range of 300 nm or more that have been generally used. .

The hydroxyalkylphenone-based compound may be any one of commercially available IRGACURE 184, DAROCUR 1173, IRGACURE 500, IRGACURE 2959 and IRGACURE 127 (brand names: all manufactured by BASF), and IRGACURE 184 is the most preferred, but limited thereto. It is not.

In an exemplary embodiment of the present specification, the compound represented by Formula 1 is preferably 5 to 15 parts by weight based on 100 parts by weight of the total curable composition.

In the exemplary embodiment of the present specification, when the compound represented by Formula 1 is within the content range, orientation is most effectively achieved, and when the content range is exceeded, orientation does not occur well.

In one embodiment of the present specification, with respect to the total 100 parts by weight of the curable composition, the hydroxyalkylphenone-based compound is preferably 0.5 to 2 parts by weight, and more preferably 0.5 to 1 parts by weight.

In the exemplary embodiment of the present specification, when the hydroxyalkylphenone-based compound exceeds the content range, the performance of the optical film may be deteriorated due to remaining unreactive materials.

In one embodiment of the present specification, the curable composition may further include a mixed solvent.

In an exemplary embodiment of the present specification, the mixed solvent includes at least two of toluene, methyl isobutyl ketone, methyl ethyl ketone, and xylene. In particular, the mixed solvent is most preferably a mixture of toluene, methyl isobutyl ketone, and methyl ethyl ketone, but is not limited thereto.

In one embodiment of the present specification, with respect to the total 100 parts by weight of the curable composition, the mixed solvent is preferably 83 to 93 parts by weight.

In an exemplary embodiment of the present specification, when the mixed solvent is toluene, methyl isobutyl ketone, and methyl ethyl ketone are mixed, toluene is 50 to 70 parts by weight, based on 100 parts by weight of the total mixed solvent, and methyl The isobutyl ketone is preferably 20 to 40 parts by weight, and the methyl ethyl ketone is preferably 5 to 20 parts by weight.

The cycloolefin polymer film has poor chemical resistance, but when toluene, methyl isobutyl ketone, and methyl ethyl ketone in the mixed solvent are within the above content range, it has excellent adhesion within a range in which the phase difference does not change.

In one embodiment of the present specification, the curable composition further includes additives commonly used in the technical field to which the present invention belongs, such as a photo initiator, surfactant, antioxidant, UV stabilizer, leveling agent, antifouling agent, in addition to the above-described components. Can include.

In the exemplary embodiment of the present specification, an acrylic resin such as poly (methyl methacrylate) (PMMA) may be further included.

In the exemplary embodiment of the present specification, the alignment layer may be formed through a curing process of applying a curable composition on a substrate and drying it.

The drying process may be performed by a conventional method, and the drying conditions are not particularly limited, and may be determined in consideration of the boiling point of the mixed solvent used in the curable composition and the material of the substrate. For example, it may be heated or slowly dried at room temperature or low temperature, but is not limited thereto.

Specifically, the curing process may be performed by irradiating light and/or heat treating the curable composition applied on the substrate. The wavelength of light used in the curing process is not particularly limited, but may be an electron beam, ultraviolet light, visible light, infrared light, or the like. In addition, the conditions of the heat treatment are not particularly limited, but may be generally performed at 10°C to 200°C for 3 seconds to 30 minutes.

In the present specification, the alignment layer may be formed by applying the curable composition on a substrate, drying at 50° C. to 80° C., and curing by irradiating ultraviolet rays under conditions of 200 mJ to 1,000 mJ of light, but limited thereto. It is not.

In the present specification, an alignment liquid crystal layer may be formed by applying a vertically aligned liquid crystal material on the cured alignment layer and vertically aligning the vertically aligned liquid crystal material through a rubbing process. In general, the vertically aligned liquid crystal material may be aligned by heating or gradually drying at room temperature or low temperature, but is not limited thereto. The vertically aligned liquid crystal material is fixed after vertical alignment. When the vertically aligned liquid crystal material is a liquid crystal monomer, it can be fixed by curing by irradiation with radiation such as ultraviolet rays, and when the vertically aligned liquid crystal material is a liquid crystal polymer. It can be fixed by cooling below the glass transition temperature, but is not limited thereto.

In the present specification, the alignment liquid crystal layer can be formed by applying a vertically aligned liquid crystal material on the cured alignment layer, drying it at 50°C to 80°C, and curing by irradiating ultraviolet rays under conditions of 200mJ to 1,000mJ of light. However, it is not limited thereto.

In the present specification, the vertically aligned liquid crystal material is preferably an acrylic resin. For example, it is preferable to use a commercially available RMM 460 (Merck Co.), but is not limited thereto.

In the exemplary embodiment of the present specification, the vertically aligned liquid crystal material may be diluted in a mixed solvent and used. The mixed solvent is the same as or different from the mixed solvent that may be included in the curable composition.

In the exemplary embodiment of the present specification, the mixed solvent in which the vertically aligned liquid crystal material is diluted may be a mixture of toluene, xylene, and diethylene glycol dimethyl ether.

1 shows an optical film according to an exemplary embodiment of the present specification. 1 illustrates the structure of an optical film in which an alignment layer 20 is provided on one surface of a substrate 10 and an alignment liquid crystal layer 30 is provided on the other surface of the alignment layer in contact with the substrate.

In one embodiment of the present specification, the thickness of the alignment layer is preferably 0.1 μm to 1 μm, and the thickness of the alignment liquid crystal layer is preferably more than 0 μm and 2 μm or less.

In one embodiment of the present specification, the stretching is performed by biaxial stretching of 1.2 times to 2 times in the machine direction (MD) and 2.4 times to 5 times in the width direction (TD). More specifically, the stretching is performed by biaxial stretching of 1.2 to 1.8 times in the machine direction and 3.5 to 5 times in the width direction (TD). If the draw ratio is less than 2.4 times in the width direction, the toughness of the film decreases, making it difficult to apply to the polarizing plate, and if it exceeds 5 times in the width direction, it is impossible to produce a stable film due to the breakage of the film during the stretching process. have.

In the present specification, "Machine Direction (MD)" is a longitudinal direction corresponding to the direction of progress during continuous production of a film, and "Transverse Direction (TD)" means a vertical direction in the MD direction.

In the exemplary embodiment of the present specification, the stretching may be performed in one of the machine direction (MD) and the width direction (TD) first and then in the other direction, or both directions may be simultaneously stretched. Further, the stretching may be performed in one step or may be performed in multiple steps.

In the exemplary embodiment of the present specification, the stretching is preferably performed at (Tg-20)°C to (Tg+30)°C when the glass transition temperature of the resin composition for manufacturing the optical film is Tg, and , Preferably Tg ℃ to (Tg+20) ℃, more preferably at a temperature of (Tg + 5) ℃ to (Tg + 20) ℃. Specifically, the stretching may be performed at 90 ℃ to 160 ℃. More specifically, it may be performed at 120 ℃ to 150 ℃.

In one embodiment of the present specification, the Tg of the optical film may be 110 ℃ to 130 ℃.

In the exemplary embodiment of the present specification, the glass transition temperature of the resin composition may be measured by a differential scanning calorimeter (DSC).

In the exemplary embodiment of the present specification, it is preferable to perform the stretching operation in the range of 10%/min to 20,000%/min, preferably 100%/min to 10,000%/min in one direction. When the drawing speed is less than 10%/min, it takes a long time to obtain a sufficient draw ratio, and there is a fear that the manufacturing cost may increase. When the stretching speed exceeds 20,000%/min, there is a fear that the stretched film may break.

In the exemplary embodiment of the present specification, the stretching may be used without limitation, as long as it is a device capable of stretching a film including a known stretching device such as a roll stretching machine or a tender-type stretching machine.

The present specification is a polarizer; And it provides a polarizing plate including the optical film provided on at least one surface of the polarizer.

At this time, the optical film may be attached to both sides of the polarizer, or may be attached only to one side. When the optical film is attached to only one surface of the polarizer, a protective film known in the art may be provided on the other surface as necessary.

The optical film according to an exemplary embodiment of the present specification is directly attached to one or both sides of a polarizer, or after attaching a protective film to both sides of the polarizer, and then attaching the optical film on the protective film to be used as a viewing angle compensation film. I can.

When attaching the optical film to one or both sides of a polarizer, protective film/polarizer/optical film, protective film/polarizer/protective film/optical film, optical film/polarizer/optical film, optical film/polarizer/protective film/optical Film or optical film/protective film/polarizer/protective film/optical film may be laminated in this order.

In one embodiment of the present specification, as the polarizer, those known in the art may be used without limitation, and for example, a film made of polyvinyl alcohol (hereinafter'PVA') containing iodine or a dichroic dye may be used. I can. The polarizer may be prepared by dyeing iodine or a dichroic dye on a PVA film, but the method of manufacturing the polarizer is not particularly limited. In the present specification, the polarizer refers to a state in which the optical film is not included, and the polarizing plate refers to a state including the polarizer and the optical film.

The attachment of the polarizer and the optical film may be performed through a method of laminating films well known in the art. For example, using a roll coater, gravure coater, bar coater, knife coater, capillary coater, etc., after coating an adhesive on the surface of the optical film or polarizer, the optical film and the polarizer are heat-laminated with a lamination roll, or at room temperature by pressing It can be carried out by a method of laminating.

As the adhesive, any material used in the art may be used without limitation, and for example, a water-based adhesive, a thermosetting adhesive, or an ultraviolet curable adhesive may be used. Specifically, polyvinyl alcohol-based adhesives, polyurethane-based adhesives, acrylic adhesives, and the like may be used, but are not limited thereto.

In an exemplary embodiment of the present specification, the total thickness of the polarizing plate may be 45 μm or more, for example, 45 μm to 250 μm, or 50 μm to 120 μm, or 50 μm to 100 μm.

In the exemplary embodiment of the present specification, the polarizing plate may be a polarizing plate for vertical alignment mode such as IPS (In-Plane Switching), Super-IPS, or FFS (Fringe Field Switching), and IPS (In-Plane Switching) is Although preferable, it is not limited thereto.

An exemplary embodiment of the present specification is a display panel; And it provides an image display device including the above-described polarizing plate attached to one or both sides of the display panel.

In the exemplary embodiment of the present specification, the display panel may be a liquid crystal panel or an organic light emitting panel, and accordingly, the image display device may be a liquid crystal display device (LCD) or an electroluminescent device (LED).

Specifically, the image display device may be a liquid crystal display device including a liquid crystal panel and polarizing plates respectively provided on both sides of the liquid crystal panel, wherein at least one of the polarizing plates is a polarizing plate according to an exemplary embodiment of the present specification described above. Can be More specifically, the liquid crystal display may include a liquid crystal cell and an upper polarizing plate and a lower polarizing plate respectively provided on both sides of the liquid crystal cell, and the optical film is between the liquid crystal cell and the upper polarizing plate and/or the lower polarizing plate. It may be provided as a viewing angle compensation film. That is, one or two or more optical films may be provided between the upper polarizing plate and the liquid crystal cell, between the lower polarizing plate and the liquid crystal cell, or between the upper polarizing plate and the liquid crystal cell, and between the lower polarizing plate and the liquid crystal cell.

In the exemplary embodiment of the present specification, the type of the liquid crystal panel included in the liquid crystal display is not particularly limited, and all known panels may be applied. In addition, other configurations constituting the liquid crystal display device, for example, the types of upper and lower substrates (eg, color filter substrates or array substrates) are not particularly limited, and configurations known in the art are not limited. Can be employed.

Hereinafter, the present specification will be described in more detail through examples. However, the following examples are for illustrating the present specification, and the scope of the present specification is not limited thereby.

< Experimental example 1-1>

(1) Preparation of curable composition

A curable composition was prepared using 5 parts by weight of the compound represented by Formula 1 (DCP-A, Gongyeong), 1 part by weight of Irgacure 184 (BASF) and 89 parts by weight of a mixed solvent as a hydroxyalkylphenone compound. The mixed solvent was mixed with 50 parts by weight of methyl ethyl ketone, 30 parts by weight of methyl isobutyl ketone, and 20 parts by weight of toluene based on 100 parts by weight of the total mixed solvent.

(2) Preparation of alignment layer and alignment liquid crystal layer

The curable composition was applied on a substrate, and ultraviolet rays were irradiated with a light amount of 700 mJ to form an alignment film. Thereafter, as a vertically aligned liquid crystal material, RMM 460 (Merck Co., Ltd.) was diluted in a mixed solvent, applied on the alignment layer, and irradiated with ultraviolet rays at an amount of 800 mJ to form an alignment liquid crystal layer. The mixed solvent was mixed with 40 parts by weight of toluene, 40 parts by weight of xylene, and 20 parts by weight of diethylene glycol dimethyl ether, based on 100 parts by weight of the total mixed solvent.

(3) Preparation of optical film

After the alignment layer and the alignment liquid crystal layer were formed, they were dried at 60° C. for 2 minutes, and then cured by irradiating ultraviolet rays with a light amount of 500 mJ to prepare an optical film.

< Experimental example 1-2>

An optical film was manufactured in the same manner as in Experimental Example 1-1, except that 10 parts by weight of the compound represented by Formula 1 was used.

< Experimental example 1-3>

An optical film was manufactured in the same manner as in Experimental Example 1-1, except that 15 parts by weight of the compound represented by Formula 1 was used.

< Experimental example 1-4>

An optical film was manufactured in the same manner as in Experimental Example 1-1, except that 3 parts by weight of the compound represented by Formula 1 was used.

< Experimental example 1-5>

An optical film was prepared in the same manner as in Experimental Example 1-1, except that the compound represented by Formula 1 was used in an amount of 20 parts by weight.

< Comparative example 1-1>

The same as in Experimental Example 1-1, except that instead of the compound represented by Chemical Formula 1, PETA (Pentaerytritol Triacrylate, Sannovco) was used, and Irgacure 907 (BASF) was used instead of the hydroxyalkylphenone compound. An optical film was prepared by the method.

< Comparative example 1-2>

An optical film was manufactured in the same manner as in Experimental Example 1-2, except that PETA was used instead of the compound represented by Chemical Formula 1, and Irgacure 907 was used instead of the hydroxyalkylphenone compound.

< Comparative example 1-3>

An optical film was prepared in the same manner as in Experimental Example 1-3, except that PETA was used instead of the compound represented by Chemical Formula 1 and Irgacure 907 was used instead of the hydroxyalkylphenone compound.

< Comparative example 1-4>

An optical film was manufactured in the same manner as in Experimental Example 1-4, except that PETA was used instead of the compound represented by Formula 1, and Irgacure 907 was used instead of the hydroxyalkylphenone compound.

< Comparative example 1-5>

An optical film was prepared in the same manner as in Experimental Example 1-5, except that PETA was used instead of the compound represented by Chemical Formula 1, and Irgacure 907 was used instead of the hydroxyalkylphenone compound.

< Comparative example 2-1>

An optical film was manufactured in the same manner as in Experimental Example 1-1, except that PETA was used instead of the compound represented by Chemical Formula 1.

< Comparative example 2-2>

An optical film was manufactured in the same manner as in Experimental Example 1-2, except that PETA was used instead of the compound represented by Chemical Formula 1.

< Comparative example 2-3>

An optical film was manufactured in the same manner as in Experimental Example 1-3, except that PETA was used instead of the compound represented by Chemical Formula 1.

< Comparative example 2-4>

An optical film was manufactured in the same manner as in Experimental Example 1-4, except that PETA was used instead of the compound represented by Chemical Formula 1.

< Comparative example 2-5>

An optical film was manufactured in the same manner as in Experimental Example 1-5, except that PETA was used instead of the compound represented by Chemical Formula 1.

< Comparative example 3-1>

An optical film was prepared in the same manner as in Experimental Example 1-1, except that Irgacure 907 was used instead of the hydroxyalkylphenone compound.

< Comparative example 3-2>

An optical film was prepared in the same manner as in Experimental Example 1-2, except that Irgacure 907 was used instead of the hydroxyalkylphenone compound.

< Comparative example 3-3>

An optical film was prepared in the same manner as in Experimental Example 1-3, except that Irgacure 907 was used instead of the hydroxyalkylphenone compound.

< Comparative example 3-4>

An optical film was prepared in the same manner as in Experimental Example 1-4, except that Irgacure 907 was used instead of the hydroxyalkylphenone compound.

< Comparative example 3-5>

An optical film was manufactured in the same manner as in Experimental Example 1-5, except that Irgacure 907 was used instead of the hydroxyalkylphenone compound.

< Evaluation example >- Crosscut Test

1 mm intervals on the surface of the optical films prepared in Experimental Examples 1-1 to 1-5, Comparative Examples 1-1 to 1-5, Comparative Examples 2-1 to 2-5, and Comparative Examples 3-1 to 3-5 After drawing 100 checkers with a Nitto Denko NT tape, the process of peeling 10 minutes after 10 reciprocating rubbing with a 100 g weight was repeated 5 times. Out of 100 cells, the number of peelings was counted, and the results are shown in Table 1 below.

Crosscut test result Experimental Example 1-1 5 Experimental Example 1-2 5 Experimental Example 1-3 5 Experimental Example 1-4 40 Experimental Example 1-5 40 Comparative Example 1-1 80 Comparative Example 1-2 80 Comparative Example 1-3 100 Comparative Example 1-4 100 Comparative Example 1-5 100 Comparative Example 2-1 40 Comparative Example 2-2 40 Comparative Example 2-3 80 Comparative Example 2-4 60 Comparative Example 2-5 80 Comparative Example 3-1 20 Comparative Example 3-2 20 Comparative Example 3-3 20 Comparative Example 3-4 30 Comparative Example 3-5 40

As shown in Table 1, it can be seen that the optical film according to the exemplary embodiment of the present specification has excellent adhesion as a result of a crosscut test. In addition, Experimental Examples 1-1 to 1-3 satisfying 5 to 15 parts by weight of the compound represented by Formula 1 based on 100 parts by weight of the total curable composition, Experimental Examples 1-4 and 1 which do not satisfy the content range Compared to -5, it can be seen that the cross-cut test has excellent adhesion.

In addition, as shown in Table 1, Experimental Examples 1-1 to 1-5 including the compound represented by Formula 1 and the hydroxyalkylphenone compound of the present specification do not include the compound represented by Formula 1 Compared to Comparative Examples 1-1 to 1-5, which is not, as a result of a crosscut test, it can be seen that adhesion is excellent.

In addition, as shown in Table 1, Experimental Examples 1-1 to 1-3 including the compound represented by Formula 1 of the present specification, Comparative Examples 2-1 to which do not include the compound represented by Formula 1 Compared to 2-5, it can be seen that the cross-cut test result is excellent in adhesion.

In addition, as shown in Table 1, Experimental Examples 1-1 to 1-5 including the hydroxyalkylphenone-based compound of the present specification, Comparative Examples 3-1 not including the hydroxyalkylphenone-based compound Compared to 3-5, it can be seen that the cross-cut test result is excellent in adhesion.

Although the preferred embodiments of the present specification have been described above, the present invention is not limited thereto, and various modifications can be made within the scope of the claims and the detailed description of the invention, and this also belongs to the scope of the invention. .

10: description
20: alignment layer
30: liquid crystal alignment layer

Claims (8)

materials;
An alignment layer in contact with at least one surface of the substrate; And
An optical film comprising an alignment liquid crystal layer provided on the other surface of the surface where the substrate of the alignment layer contacts,
The substrate is a cycloolefin polymer film,
The alignment layer is a compound represented by the following formula (1); And a cured product of a curable composition comprising a hydroxyalkylphenone compound,
The alignment liquid crystal layer is an optical film made of a vertically aligned liquid crystal material:
[Formula 1]

In Formula 1,
a1 and a2 are each an integer of 1 to 6,
When a1 and a2 are each 2 or more, the structures in the two or more parentheses are the same or different from each other,
L1 and L2 are the same as or different from each other, and each independently a substituted or unsubstituted alkylene group; Or a substituted or unsubstituted arylene group,
R1 and R2 are the same as or different from each other, and each independently a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms. The optical film according to claim 1, wherein the compound represented by Formula 1 is contained in an amount of 5 to 15 parts by weight based on 100 parts by weight of the curable composition. The optical film of claim 1, wherein the hydroxyalkylphenone-based compound is contained in an amount of 0.5 to 2 parts by weight based on 100 parts by weight of the total curable composition. The optical film of claim 1, wherein the curable composition further comprises a mixed solvent. The optical film according to claim 4, wherein the mixed solvent contains at least two of toluene, methyl isobutyl ketone, methyl ethyl ketone, and xylene. The optical film of claim 1, wherein the alignment layer has a thickness of 0.1 µm to 1 µm. Polarizer; And
A polarizing plate comprising the optical film according to any one of claims 1 to 6 provided on at least one surface of the polarizer. Display panel; And
An image display device comprising the polarizing plate according to claim 7 attached to one or both surfaces of the display panel.

Images