KR102183981B1 - Polyester film and organic light emitting display using same - Google Patents

Abstract

An embodiment relates to a polyester film and an organic light emitting display device using the same, wherein the polyester film has excellent optical properties, durability, heat resistance, and color implementation by satisfying at least 40% of light transmittance and greater than 50% of a polarization degree in a wavelength range of 380-780 nm and comprising: a base material layer having a polyester resin; and a coating layer formed on the base material layer and containing a dichroic dye.

Description

Polyester film and organic light emitting display device using the same {POLYESTER FILM AND ORGANIC LIGHT EMITTING DISPLAY USING SAME}

The embodiment relates to a polyester film having excellent optical properties, durability, heat resistance, and color realization, and an organic light emitting display device using the same.

Flat panel displays are used in various electronic products such as mobile phones, tablet PCs, and notebook computers. These flat panel displays include a liquid crystal display and an organic light emitting display. ) Is widely used.

The liquid crystal display device requires a polarizing film having a high degree of polarization in order to effectively transmit light from a backlight. On the other hand, the organic light emitting display device uses an organic light emitting device that is a self-luminous device that emits light when a voltage is applied, so a polarizing film is used to accurately implement a black screen and secure outdoor visibility.

Conventionally, despite the difference in required characteristics of the liquid crystal display device and the organic light emitting display device, the polarizing film used in the liquid crystal display device has been used as it is in the organic light emitting display device. However, in the case of an organic light-emitting display device, since optical characteristics of high polarization are not required, development of a polarizing film capable of securing color realization and outdoor visibility while having optical characteristics suitable for the organic light-emitting display device is required.

For example, in Japanese Laid-Open Patent No. 2005-266502, since the polarization degree of the polarizing film is 95% or more but at least 40% of the transmittance, the high polarization required by the liquid crystal display device is satisfied, but the color realization is low due to high light loss. It is not suitable for light emitting display devices.

Japanese Laid-Open Patent Publication No. 2005-266502

Accordingly, an embodiment is to provide a polyester film having excellent optical properties suitable for an organic light emitting display device, as well as durability, heat resistance, and color realization, and an organic light emitting display device using the same.

A polyester film according to one embodiment includes a base layer comprising a polyester resin; And a coating layer formed on the base layer and including a dichroic dye, and a polarization degree of more than 50% and a light transmittance of 40% or more in a wavelength range of 380 nm to 780 nm.

The polarizing plate for an organic light-emitting device according to an embodiment includes a polyester film according to the embodiment.

An organic light-emitting display device according to an embodiment includes the polarizing plate for an organic light-emitting device according to the embodiment.

A method of manufacturing a polyester film according to an embodiment includes the steps of: (1) melt-extruding a polyester resin to prepare an unstretched sheet; (2) first stretching the unstretched sheet in a first direction; (3) coating a composition containing a dichroic dye on the first stretched sheet; And (4) secondary stretching the coated sheet in a second direction perpendicular to the first direction.

The polyester film according to the embodiment is excellent in durability, heat resistance, and color realization as well as optical properties suitable for an organic light emitting display device.

Hereinafter, the invention will be described in detail through embodiments. The implementation is not limited to the content disclosed below, and may be modified in various forms unless the gist of the invention is changed.

In the present specification, when each layer, film or sheet is described as being formed on or under each layer, film or sheet, it is directly or indirectly through other components. It includes everything that is formed (indirectly).

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.

All numbers and expressions indicating amounts of components, reaction conditions, and the like described herein are to be understood as being modified by the term "about" in all cases unless otherwise specified.

[Polyester film]

A polyester film according to one embodiment includes a base layer comprising a polyester resin; And a coating layer formed on the base layer and including a dichroic dye, and has a polarization degree of more than 50% and a light transmittance of 40% or more in a wavelength range of 380 nm to 780 nm.

According to one embodiment, the base layer is a polyester resin layer.

According to one embodiment, the polyester resin of the base layer may include a diol component and a dicarboxylic acid component. Specifically, the base layer may be formed of a polyester resin containing a diol component and a dicarboxylic acid component.

According to one embodiment, the diol component may consist of a linear or branched aliphatic C ₂ to C ₁₀ diol. That is, the diol component may not contain an alicyclic diol or an aromatic diol. In the case of manufacturing a film or sheet by melt extrusion using a polyester resin containing a diol component consisting of the linear or branched aliphatic C ₂ to C ₁₀ diol, packing is well done, so the chemical resistance of the film and Surface strength can be excellent.

Specifically, the linear or branched aliphatic C ₂ to C ₁₀ diol is ethylene glycol, diethylene glycol, neopentyl glycol, 1,3-propanediol, 1,2-octanediol, 1,3-octanediol, 2 ,3-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 2-butyl-2-ethyl-1,3-propanediol, 2,2-diethyl-1,5- Pentanediol, 2,4-diethyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,1-dimethyl-1,5-pentanediol, 1,6-hexanediol, 2- Ethyl-3-methyl-1,5-hexanediol, 2-ethyl-3-ethyl-1,5-hexanediol, 1,7-heptanediol, 2-ethyl-3methyl-1,5-heptanediol, 2 Derivatives such as -ethyl-3-ethyl-1,6-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, or any combination thereof may be included. It is not limited.

According to one embodiment, the diol component includes at least one selected from the group consisting of ethylene glycol, diethylene glycol, cyclohexanedimethanol (CHDM), propanediol, butanediol, pentanediol, hexanediol, and octanediol In this case, the diol component may be substituted or unsubstituted with a C ₁ to C ₆ alkyl group.

According to one embodiment, the diol component is ethylene glycol, diethylene glycol, 1,4-cyclohexanedimethanol, 1,3-propanediol, 1,2-octanediol, 1,3-octanediol, 2,3 -Butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, neopentyl glycol, 2-butyl-2-ethyl-1,3-propanediol, 2,2-diethyl-1, 5-pentanediol, 2,4-diethyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,1-dimethyl-1,5-pentanediol, or a combination thereof. have.

According to one embodiment, the diol component may be at least one selected from the group consisting of ethylene glycol, diethylene glycol, neopentyl glycol, and cyclohexanedimethanol.

According to one embodiment, the polyester resin may contain 30 mol% to 90 mol% of ethylene glycol based on the total number of moles of the diol component. For example, the polyester resin may contain 40 mol% to 90 mol%, 50 mol% to 85 mol%, or 65 mol% to 85 mol% of ethylene glycol based on the total number of moles of the diol component.

According to one embodiment, the polyester resin may include neopentyl glycol in an amount of 30 to 90 mol% based on the total number of moles of the diol component. For example, the polyester resin is 35 mol% to 90 mol%, 35 mol% to 80 mol%, 35 mol% to 75 mol%, 35 mol% to 70 mol%, based on the total number of moles of the diol component, It may contain 40 mol% to 65 mol% and 40 mol% to 60 mol% of neopentyl glycol. If the above range is satisfied, it may be easy to control crystal properties.

The dicarboxylic acid component may include aromatic dicarboxylic acids such as terephthalic acid, dimethyl terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, and orthophthalic acid; Aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid, and decanedicarboxylic acid; Alicyclic dicarboxylic acid; Esterified products thereof; Or it may be a combination of these. Specifically, the dicarboxylic acid component may be made of terephthalic acid, dimethyl terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, orthophthalic acid, or a combination thereof.

According to one embodiment, the dicarboxylic acid component may include an aromatic dicarboxylic acid. For example, the dicarboxylic acid component may include 80 mol% or more, 90 mol% or more, or 95 mol% or more of terephthalic acid in terms of the total number of moles of the dicarboxylic acid component.

According to one embodiment, the intrinsic viscosity (IV) of the polyester resin may be 0.60 dl/g to 3.0 dl/g. For example, the intrinsic viscosity of the polyester resin may be 0.63 dl/g to 1.2 dl/g, 0.65 dl/g to 1.1, or 0.67 dl/g to 1.0 dl/g. When the above range is satisfied, the calendering processability is excellent, the kinematic viscosity retention rate is excellent during the calendering process, and the thickness uniformity of the sheet and film is excellent.

According to one embodiment, the amount of heat for crystallization of the polyester resin may be 2.5 J/g or less. For example, the amount of heat for crystallization of the polyester resin may be 0 to 2.2 J/g or 0 to 2 J/g. When the above range is satisfied, there is an effect of improving calender workability.

According to one embodiment, the coating layer may include 0.5% by weight or more to less than 50% by weight of the dichroic dye based on the total weight of the coating layer. For example, the coating layer may include 0.5% by weight or more to less than 20% by weight, 4% to 18% by weight, or 4% to 16% by weight of a dichroic dye based on the total weight of the coating layer. . Specifically, the coating layer may include 4% by weight or more to less than 20% by weight of the dichroic dye based on the total weight of the coating layer. When the above range is satisfied, optical properties of light transmittance, haze, and polarization degree suitable for an organic light emitting display device may be obtained, and dispersibility of the coating layer due to excessive inclusion of dichroic dyes may be prevented.

According to one embodiment, the dichroic ratio of the dichroic dye may be 1.5 to 14. For example, the dichroic ratio of the dichroic dye may be 2 to 14, 3 to 14, or 4 to 14.

According to one embodiment, the dichroic dye may have an absorbance of 0.4 or less in a wavelength range of 380 nm to 780 nm. For example, the dichroic dye may have an absorbance of 0.39 or less or 0.38 or less in a wavelength range of 380 nm to 780 nm.

According to one embodiment, the melting point (Tm) of the dichroic dye may be 100 ℃ to 140 ℃. For example, the melting point (Tm) of the dichroic dye may be 100°C to 130°C or 110°C to 140°C.

According to one embodiment, the dichroic dye is an azo compound, an anthraquinone compound, an azomethine compound, an indigo compound, a thioindigo compound, a cyanine compound, a phosphorus compound, an azulene compound, a perylene compound, It may be a phthaloperinone compound or an azine compound.

According to one embodiment, the coating layer may further include a primer.

According to one embodiment, the primer may include at least one selected from the group consisting of a binder resin, a curing agent, a dispersant, and a surfactant.

According to one embodiment, the binder resin may include at least one selected from the group consisting of acrylic resins, polyurethane resins, and polyester resins.

The acrylic resin is dipentaerythritol pentaacrylate, trihydroxy ethyl isocyanurate triacrylate, di(meth)acryloxy ethyl isocyanurate, isocyanurate di(meth)acrylate, trimethylol propane Tri(meth)acrylate, trimethylol propane triacrylate, ethylene oxide modified hexahydrophthalic acid di(meth)acrylate, dipentaerythritol tri(meth)acrylate, propionic acid modified dipentaerythritol tri(meth)acrylic Rate, pentaerythritol tri(meth)acrylate, dimethylol dicyclopentane di(meth)acrylate, propylene oxide-modified trimethylolpropane tri(meth)acrylate, tricyclodecane dimethanol(meth)acrylate, tris (Acryloxyethyl) isocyanurate, propionic acid-modified dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) acrylate, or these It may be a combination, but is not limited thereto.

The polyurethane resin may include a polyester urethane resin, but is not limited thereto. For example, the polyurethane resin may be a water-dispersible polyurethane resin, and commercially available products include HYDRAN AP-20 from DIC, but are not limited thereto.

The polyester resin may be polyethylene terephthalate or copolymerized polyethylene terephthalate, but is not limited thereto.

According to one embodiment, the thickness of the coating layer may be 100 nm or less. For example, the thickness of the coating layer may be 10 nm to 100 nm, 20 nm to 100 nm, 30 nm to 100 nm, 30 nm to 80 nm, 30 nm to 70 nm, or 30 nm to 60 nm.

According to one embodiment, the coating layer may include 5% to 30% by weight of the binder resin based on the total weight of the coating layer. For example, the coating layer may include a binder resin of 5% to 25% by weight, 8% to 20% by weight, or 10% to 15% by weight based on the total weight of the coating layer.

If necessary, the primer may include a curing agent, a surfactant, and a dispersing agent commonly used in the art to accelerate reaction or improve coating properties.

The curing agent is generally used in the art and is not particularly limited, but, for example, an oxalin-based, epoxy-based, carboimide-based, melamine-based curing agent or the like may be used.

The dispersant is generally used in the art and is not particularly limited, but, for example, alkali metal compounds such as sodium hydroxide, potassium hydroxide, sodium carbonate, isopropyl tristearyl titanate, isopropyl tridodecylbenzene sulfonyl titanate Titanium compounds such as nate and tetraoxyl titanium oxide, silane compounds, carboxylic acid compounds such as polycarboxylic acid and polycarboxylate, vinylpyrrolidone compounds such as polyvinylpyrrolidone and N-vinylpyrrolidone Compounds can be used.

The surfactant is used to improve the dispersibility of the particles and is not particularly limited, for example, a surfactant having at least one functional group selected from the group consisting of an alkoxy group, a hydroxy group, an amine group and a conjugated double bond may be used. have.

According to one embodiment, the weight ratio of the binder resin and the dichroic dye may be 2 to 20:1. For example, the weight ratio of the binder resin and the dichroic dye is 2.5 to 20:1, 2.5 to 15:1, 3 to 13:1, 3 to 10:1, 3 to 8:1, or 3 to 5:1 Can be When the above range is satisfied, optical properties of light transmittance, haze, and polarization degree suitable for an organic light emitting display device may be obtained.

According to one embodiment, the polarization degree of the polyester film is more than 50% in the wavelength range of 380 nm to 780 nm. For example, the polarization degree of the polyester film in the wavelength range of 380 nm to 780 nm is 50% or more, 53% or more, 55% or more, 50% to 90%, 50% to 85%, 50% to 80%, 53% to 80%, 54% to 80%, 54% to 75%, 54% to 70%, 54% to 65%, or 54% to 60%.

According to one embodiment, the light transmittance of the polyester film is 40% or more. Specifically, the light transmittance of the polyester film in the wavelength range of 380 nm to 780 nm is 40% or more. For example, the light transmittance of the polyester film is 50% or more, 55% or more, 60% or more, 65% or more, 40% to 90%, 50% to 80%, 55% to 75%, 60% to 75 %, or 65% to 75%.

According to one embodiment, the haze of the polyester film is 10% or less. For example, the haze of the polyester film may be 9% or less, 8.5% or less, 3% to 9%, 4% to 9%, 5% to 8.5%, or 5.5% to 8.5%.

According to one embodiment, the thickness of the polyester film may be 10 ㎛ to 200 ㎛. For example, the thickness of the polyester film is 10 µm to 188 µm, 10 µm to 125 µm, 20 µm to 188 µm, 23 µm to 125 µm, 30 µm to 188 µm, 38 µm to 125 µm, or 38 µm It may be to 100 μm.

The polyester film may be used as a polarizing film.

The polarizing plate for an organic light-emitting device according to an embodiment includes a polyester film according to the embodiment.

An organic light-emitting display device according to an embodiment includes the polarizing plate for an organic light-emitting device according to the embodiment.

[Method for producing polyester film]

A method of manufacturing a polyester film according to an embodiment includes the steps of: (1) melt-extruding a polyester resin to prepare an unstretched sheet; (2) first stretching the unstretched sheet in a first direction; (3) coating a composition containing a dichroic dye on the first stretched sheet; And (4) secondary stretching the coated sheet in a second direction perpendicular to the first direction.

Step (1)

The step (1) is a step of manufacturing an unstretched sheet by melt extrusion of a polyester resin.

According to one embodiment, the polyester resin is prepared by polymerizing a diol component and a dicarboxylic acid component using at least one catalyst selected from the group consisting of a germanium compound, an antimony compound, an aluminum compound, and a titanium compound. I can.

The description of the diol component and the dicarboxylic acid component is as described above.

According to one embodiment, the melt extrusion may be performed at 250°C or higher.

For example, it may be performed at a temperature of 255°C or higher, 260°C or higher, 270°C or higher, 280°C or higher, 200°C to 300°C, 230°C to 280°C, or 250°C to 280°C. The polyester film has an advantageous effect in that the heat resistance is strong even in the above temperature range and no defect occurs. Specifically, in the case of using a non-dichroic dye that does not have a substantial dichroic ratio, it is not suitable because thermal decomposition may occur at the melt extrusion process temperature. For example, the non-dichroic dye may have a dichroic ratio of less than 1, but is not limited thereto.

Step (2)

The step (2) is a step of first stretching the unstretched sheet in a first direction.

According to one embodiment, the sheet may be preheated at a predetermined temperature before stretching. The preheating temperature may be Tg+5°C to Tg+50°C based on the glass transition temperature (Tg) of the resin. For example, the preheating temperature may be 70 ℃ to 90 ℃. When the above range is satisfied, the sheet can be easily stretched, and at the same time, it is possible to effectively prevent the phenomenon from being broken during stretching.

In the present specification, the first direction may be a longitudinal direction (MD) and a transverse direction (TD). For example, the first direction may be a vertical direction MD, and a second direction perpendicular to the first direction may be a transverse direction TD. Alternatively, the first direction may be a transverse direction TD, and a second direction perpendicular to the first direction may be a longitudinal direction MD.

According to one embodiment, the first draw ratio may be 1.0 to 4.0. For example, it may be 1.0 to 3.5, 1.3 to 3.5, 1.5 to 3.3, or 1.5 to 3.0.

According to one embodiment, the temperature during stretching in the first direction may be 55°C to 120°C. For example, the stretching in the first direction may be performed at 70°C to 120°C or 80°C to 110°C.

Step (3)

The step (3) is a step of coating a composition including a dichroic dye on the first stretched sheet.

The description of the dichroic dye is as described above.

According to one embodiment, the coating may be spin coating or inline coating. Specifically, in-line coating is preferred in order to secure heat resistance, but is not limited thereto.

Step (4)

The step (4) is a step of secondary stretching the coated sheet in a second direction perpendicular to the first direction.

According to one embodiment, the sheet may be preheated at a predetermined temperature before stretching. The preheating temperature may be Tg+5°C to Tg+50°C based on the glass transition temperature (Tg) of the resin. For example, the preheating temperature may be 70 ℃ to 90 ℃. When the above range is satisfied, the sheet can be easily stretched, and at the same time, it is possible to effectively prevent the phenomenon from being broken during stretching. In the present specification, the second direction may be a longitudinal direction (MD) or a transverse direction (TD).

According to one embodiment, the draw ratio in the second direction may be 2.0 to 5.0. For example, it may be 2.0 to 4.8, 2.5 to 4.5, 2.5 to 4.3 or 3.0 to 4.0.

According to one embodiment, the temperature during stretching in the second direction may be 55°C to 120°C. For example, the stretching in the second direction may be performed at 90°C to 120°C or 100°C to 120°C.

According to one embodiment, the ratio of the draw ratio of the first draw and the draw ratio of the second draw (that is, the ratio of the first draw ratio and the second draw ratio) may be 1: 1 to 5. For example, the ratio of the draw ratio of the primary stretching and the draw ratio of the secondary stretching may be 1:1 to 4, 1:1 to 3, or 1:1 to 2.

According to one embodiment, the maximum process temperature in steps (1) to (4) may be 250°C or higher. For example, the maximum process temperature in steps (1) to (4) is 255°C or higher, 260°C or higher, 270°C or higher, 280°C or higher, 200°C to 300°C, 230°C to 280°C, or 250°C to 280°C. It may be °C. The polyester film has an advantageous effect in that the heat resistance is strong even in the above temperature range and no defect occurs.

[Example]

The above will be described in more detail by the following examples. However, the following examples are for illustrative purposes only, and the scope of the examples is not limited thereto.

Example 1

In a stainless steel autoclave equipped with a stirrer, thermometer, and partial reflux cooler, terephthalic acid (TPA) as a dicarboxylic acid component and ethylene glycol (EG) as a diol component were mixed at a molar ratio of 1.7:1.0, and the resulting methanol was added thereto. The transesterification reaction proceeded while distilling off. Thereafter, a polycondensation reaction was performed under reduced pressure conditions of 26.6 Pa (0.2 Torr) at 280° C. to obtain a polyester resin.

The resin was melt-extruded in an extruder at 280° C. and guided to a T-Die to form an unstretched sheet, and then the sheet was first stretched in the MD direction at a stretching ratio of 1.0 to 1.5 using a stretching device.

To prepare a composition containing 10 g of a binder resin (polyester Z690 from Goo Chemical), 5 g of a dichroic dye (Chlorazol black from Sigma-Aldrich), 10 g of a curing agent (WS500 from Japan Catalyst), and other additives and distilled water in an appropriate amount. After that, the sheet was coated with the composition.

The coated sheet was secondarily stretched at a draw ratio of 3.0 to 4.8 in the TD direction to prepare a polyester film having a thickness of 50 μm.

Examples 2 to 6 and Comparative Examples 1 to 3

The procedure of Example 1 was repeated, but a polyester film was prepared by changing the components and contents of the coating layer as described in Table 1 below.

Meanwhile, in Comparative Example 1, a composition in which only a dye was mixed with water without a binder was used as a coating solution, and in this case, the adhesion between the coating solution and the polyester resin layer was low, so that a coating layer was not formed on the polyester resin layer.

In addition, in Comparative Examples 2 and 3, a general dye (FASTOGEN, DIC) was used, not a dichroic dye.

division Binder resin content (g) dyes
Content(g) Binder Resin: Dye
Weight ratio In the coating layer
Dye content (% by weight) Comparative Example 1 - - - - Example 1 10 5.0 2: 1 12.00 Example 2 10 2.5 4: 1 6.00 Example 3 10 2.0 5: 1 3.33 Example 4 10 1.5 6.7: 1 2.61 Example 5 10 1.0 10: 1 1.82 Example 6 10 0.5 20: 1 0.95 Comparative Example 2 10 3.0 3.3: 1 4.62 Comparative Example 3 10 2.5 4: 1 4.00

Evaluation Example 1: Light transmittance

Light transmittance was measured using a UV-spectrometer (Shimazu, Japan, UV-2450).

Evaluation Example 2: Haze

Haze was measured using a haze meter NDH-5000W manufactured by Denshoku High School in Japan.

Evaluation Example 3: Degree of polarization

The degree of polarization was measured using a UV-spectrometer (Shimazu, Japan, UV-2450).

Evaluation Example 4: Moisture resistance

By cutting into a size of 10 cm X 10 cm, two polyester films were prepared. After overlapping so that one side of the two polyester films are in contact with each other, it was compressed for 24 hours at 80°C/80%RH with a 10 kg load. Thereafter, after cooling the compressed polyester film to room temperature, the change in transmittance of the film was measured. If the transmittance change was 1% or more, it was expressed as X, and if it was less than 1, it was expressed as O.

The results of Evaluation Examples 1 to 4 are shown in Table 2 below.

division Light transmittance (%) Haze (%) Polarization (%) Moisture resistance Comparative Example 1 53.31 31.21 53 X Example 1 50.66 1.11 80 O Example 2 50.35 1.84 60 O Example 3 51.47 2.76 58 O Example 4 51.53 2.57 57 O Example 5 53.52 2.35 56 O Example 6 59.36 2.22 51 O Comparative Example 2 52.52 21.11 0.5 X Comparative Example 3 51.37 19.43 0.2 X

As shown in Table 2 above, the polyester film prepared in the Example is used in an organic light emitting display device because it has excellent light transmittance, polarization degree, optical properties of haze, and moisture resistance in a balance compared to the film prepared in Comparative Example. It can be seen that it is suitable for the following. Specifically, the polyester film of the Example using a dichroic dye is excellent in balance with light transmittance, polarization degree, and optical properties of haze, and moisture resistance, whereas Comparative Example 1 without using a dye and Comparative Example using a general dye It can be seen that 2 and 3 have poor haze, polarization degree and moisture resistance.

Claims (18)

A base layer comprising a polyester resin; And
It is formed on the base layer and includes a coating layer comprising a dichroic dye and a binder resin,
The dichroic dye is an azo compound, an anthraquinone compound, an azomethine compound, an indigo compound, a thioindigo compound, a cyanine compound, a phosphorus compound, an azulene compound, a perylene compound, a phthaloperinone compound, or It is a azine compound,
The binder resin includes at least one selected from the group consisting of acrylic resin, polyurethane resin, and polyester resin,
A polyester film having a polarization degree of more than 50% and a light transmittance of 50% or more in a wavelength range of 380 nm to 780 nm.
The method of claim 1,
The polyester film has a haze of 10% or less and a thickness of 10 μm to 200 μm.
The method of claim 1,
A polyester film in which the polyester resin of the base layer contains a diol component and a dicarboxylic acid component.
The method of claim 1,
The polyester film, wherein the coating layer comprises 4% by weight or more to less than 20% by weight of the dichroic dye based on the total weight of the coating layer.
The method of claim 1,
The dichroic ratio of the dichroic dye is 1.5 to 14, the polyester film.
The method of claim 1,
The polyester film, wherein the dichroic dye has an absorbance of 0.4 or less in a wavelength range of 380 nm to 780 nm.
delete The method of claim 1,
The coating layer further comprises at least one selected from the group consisting of a curing agent, a dispersant and a surfactant, a polyester film.
delete The method of claim 1,
The polyester film, wherein the coating layer comprises 5% to 30% by weight of the binder resin based on the total weight of the coating layer.
The method of claim 1,
The weight ratio of the binder resin and the dichroic dye is 2 to 20: 1, the polyester film.
The method of claim 1,
The polyester film is used as a polarizing film, a polyester film.
A polarizing plate for an organic light-emitting device comprising the polyester film according to any one of claims 1 to 6, 8, and 10 to 12.
An organic light-emitting display device comprising the polarizing plate for an organic light-emitting device of claim 13.
(1) melt-extruding a polyester resin to prepare an undrawn sheet;
(2) first stretching the unstretched sheet in a first direction;
(3) coating a composition including a dichroic dye and a binder resin on the first stretched sheet; And
(4) secondary stretching the coated sheet in a second direction perpendicular to the first direction,
The dichroic dye is an azo compound, an anthraquinone compound, an azomethine compound, an indigo compound, a thioindigo compound, a cyanine compound, a phosphorus compound, an azulene compound, a perylene compound, a phthaloperinone compound, or It is a azine compound,
The binder resin includes at least one selected from the group consisting of acrylic resin, polyurethane resin, and polyester resin,
In the above steps (1) to (4), the maximum process temperature is 250° C. or higher, a method for producing a polyester film.
The method of claim 15,
Preparation of a polyester film wherein the polyester resin is prepared by polymerizing a diol component and a dicarboxylic acid component using at least one catalyst selected from the group consisting of a germanium compound, an antimony compound, an aluminum compound and a titanium compound Way.
The method of claim 15,
The ratio of the draw ratio of the primary stretching and the draw ratio of the secondary stretching is 1:1 to 5, a method for producing a polyester film.
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