TW201418024A - Polyester film - Google Patents

Abstract

Provided is a polyester film for shielding an oligomer through a primer layer, and more particularly, an oligomer blocking polyester film capable of blocking the oligomer from migrating and having a low haze changing rate to thereby be used as an optical use.

Description

Polyester film

This invention relates to a polyester film, and more particularly to an oligopolymer barrier polyester film capable of blocking migration of oligopolymers and having a low haze change rate.

An optical film, which is a film used as an optical element of a display, is generally used as an optical material of a liquid crystal display (LCD) backlight unit (BLU) or as a protection for various displays such as an LCD, a plasma display panel (PDP), a touch panel, and the like. The optical components of the surface.

The optical film requires excellent transparency and visibility, and a biaxially stretched polyester film having excellent mechanical and electrical properties as a base film.

In the biaxially stretched polyester film, since the surface hardness is low and abrasion resistance or scratch resistance is insufficient, when the film is used as an optical element of various displays, surface damage is caused by friction or contact with an object. Easy to happen. Therefore, in order to prevent this damage, a hard coat layer is laminated on the surface of the film, and a primer layer is used as an interlayer to improve the adhesion between the polyester film (i.e., the base film) and the hard coat layer.

Among the polyester films used in displays, there are many quality problems associated with oligopolymers. For example, in a post-treatment process of a polyester film, when heated during a curing process after ruthenium coating or diffusion coating, the oligopolymer moves in the polyester film, causing whitening and whitening its surface. As shown in Figure 1. Further, as shown in Fig. 2, the pressure of the diamond-shaped pattern roll used in the cutting process after the production of the polyester film also forms a diamond-shaped pattern, resulting in a so-called diamond-shaped mark phenomenon.

In the case of the phenomenon of whitening and diamond marking as described above, the film The roll may be contaminated by such processes, causing the optical properties of the final product to decrease.

In order to prevent the movement of the oligomer in the polyester film, attempts have been made to reduce the content of the oligomer in the polymerization of the polyester film, but it is still difficult to completely prevent the oligomer.

Further, in order to form a laminate film on a polyester film for controlling leakage of an oligopolymer, a method has been disclosed on at least one surface thereof in Japanese Patent Laid-Open Publication No. 2007-253511 (December 4, 2007) A polyester film having a laminate film in which the average area of the oligo polymer particles deposited on the laminate film after heating the film to 150 ° C for 60 minutes is 10 μm ² or less And the number of oligopolymer particles is 100 or less in a field of view of 100 μm × 100 μm. Although the above invention is intended to control the leakage of the oligomeric polymer, it does not completely block the leakage of the oligomeric polymer.

It is an object of the present invention to provide a polyester film which is capable of completely blocking the leakage of an oligopolymer.

Another object of the present invention is to provide a polyester film capable of suppressing an increase in haze due to surface leakage of an oligomeric polymer during heat treatment, and having a haze change of 0.1% or less. rate.

In order to achieve the above objects, the inventors conducted research and found that by using a specific water-dispersible resin composition having an oligopolymer barrier property as a composition to form a primer layer, the leakage of the oligopolymer can be blocked, and Therefore, the polyester film having a significantly lower haze change rate after heating than the prior art can be manufactured, thereby completing the present invention.

Further, a crosslinking agent having a specific structure is used in the water-dispersible resin composition, whereby the barrier property of the oligomer can be further improved, and the strength of the coating layer can be increased, thereby improving scratch resistance and solvent resistance. Therefore, surface defects generated during the post-treatment process can be reduced. Meanwhile, the inventors have found that since the reaction rate can be further increased by using a crosslinking agent having a specific structure, the low reaction conversion rate of the crosslinking agent due to the characteristics of the film formation process can be increased, and the primer layer can be overcome. Increased haze and deterioration of properties of the primer layer caused by unreacted and residual cross-linking agent, and improved oligopolymer due to increased degree of cross-linking The polyester film which blocks the properties, thereby completing the present invention.

In one aspect, a polyester film of the present invention comprises a polyester base film; and a primer layer coated on the surface of the polyester base film or on both surfaces A polymer-blocking property of a water-dispersible resin composition was formed in which, after holding it at 150 ° C for 60 minutes, the haze change rate (ΔH) was 0.1% or less according to the following Equation 1.

[Equation 1] △H(%)=H _f -H _i

(In Equation 1, H _f is the haze (%) of the film after holding at 150 ° C for 60 minutes, and H _i is the haze of the film before heating.)

The primer layer has a Tg of 60 ° C or more, a coefficient of expansion of 30% or less, a colloid fraction of 95% or more, and a density of 1.3 to 1.4.

After the polyester film was heated at 150 ° C for 60 minutes, the amount of the oligomeric polymer particles precipitated on the surface of the film was 10 or less (per 10,000 μm ² ), and the area thereof was 20 μm ² or less on average (per 10000 μm ² ).

The water-dispersible resin composition may include an acrylic resin copolymerized with a glycidyl group-containing radically polymerizable unsaturated monomer, and a water-dispersible polyester-based resin as a binder resin.

In the water-dispersible resin composition, the solid content weight ratio (A:B) of the glycidyl group-containing radically polymerizable unsaturated monomer copolymerized acrylic resin to the water-dispersible polyester-based resin may be 20~ 80: 80~20% by weight.

The water-dispersible resin composition may include the binder resin and water to have a solid content of 0.5 to 10% by weight.

The water-dispersible resin composition may further include 0.1 to 0.5% by weight of a decane-based wetting agent.

The water-dispersible polyester-based resin may be a copolymer of a dicarboxylic acid component including an alkali metal sulfonate.

The water-dispersible polyester-based resin may contain diethylene glycol in an amount of 20 to 80 mol% based on the total diol component.

The water-dispersible polyester-based resin may contain an alkali metal sulfonate compound in an amount of 6 to 20 mol% based on the total acid component.

The acrylic resin may contain, as a comonomer, a glycidyl group-containing radically polymerizable unsaturated monomer in an amount of 20 to 80 mol% based on the total monomer component.

The water-dispersible resin composition may further include any one of the compounds represented by Chemical Formulas 1 and 2 or a mixture thereof.

(In Chemical Formula 1, A ₁ or A ₃ is a chemical bond or a (C1-C10) alkylene group, respectively, and R ₁ to R ₃ are each independently selected from hydrogen and (C1-C10) alkyl.)

(In Chemical Formula 2, A ₁ to A ₃ are each a (C1-C10) alkylene group and B is a blocking agent.)

The content of any one of the compounds represented by Chemical Formulas 1 and 2 or a mixture thereof may be from 0.1 to 10% by weight.

The compound of Chemical Formula 1 may be the following compound.

The polyester base film may be a polyethylene terephthalate film.

The polyester-based film may have a thickness of 25 to 250 μm.

The primer layer may have a dry coating thickness of 20 to 200 nm.

The water-dispersible resin composition can be applied in an in-line manner during the production process of the polyester film.

The polyester film as described above may be a film for a display.

The polyester film according to the present invention can have optical properties suitable for an optical film, block oligopolymer leakage, and prevent an increase in haze.

10‧‧‧ polyester base film

20‧‧‧First primer layer

30‧‧‧Second primer layer

Fig. 1 is a photograph showing the whitening phenomenon of a polyester film in which an oligopolymer leaks; Fig. 2 is a photograph showing a rhombic marking phenomenon of a polyester film in which an oligopolymer leaks; and Fig. 3 shows a photograph according to the present invention. A cross section of the polyester film on the one hand; and Fig. 4 shows a cross section of the polyester film according to the second aspect of the invention.

Hereinafter, the structure of the present invention will be described in detail.

One aspect of the invention relates to a polyester film comprising a polyester base film 10 and a primer layer 20 on a surface of the polyester base film 10, as shown in Fig. 3. It is shown that, after holding it at 150 ° C for 60 minutes, the haze change rate (ΔH) was 0.1% or less according to the following Equation 1.

[Equation 1] △H(%)=H _f -H _i

(In Equation 1, H _f is the haze (%) of the film after holding at 150 ° C for 60 minutes, and Hi is the haze of the film before heating.)

A second aspect of the invention relates to a polyester film comprising a polyester base film 10 and first and second primer layers 20 and 30, the first and second primer layers 20 and 30 being On both surfaces of the polyester base film 10, after maintaining it at 150 ° C for 60 minutes, the haze change rate (ΔH) was 0.1% or less according to the following Equation 1.

[Equation 1] △H(%)=H _f -H _i

(In Equation 1, H _f is the haze (%) of the film after holding at 150 ° C for 60 minutes, and H _i is the haze of the film before heating.)

In the polyester film according to the present invention, a primer layer is formed by applying a water-dispersible resin composition having an oligomer polymer barrier property. The present invention is accomplished by finding that the use of a specific resin as a water-dispersible resin composition having an oligopolymer barrier property can significantly improve the barrier property of the oligomer, so that the haze change rate after heating is remarkably improved to 0.1% or less, more preferably Ground, 0 to 0.1%, thereby completing the present invention. Further, by finding any one or a mixture of the compounds represented by Chemical Formula 1 and Chemical Formula 2 according to the present invention, further including the water-dispersible resin composition to complete the present invention, the rate of change in haze can be further improved to 0.05% or Smaller, better, 0 to 0.05%,

Further, in the first and second aspects of the invention, the primer layer may have a Tg of 69 ° C or more, a coefficient of expansion of 30% or less, a colloid fraction of 95% or more, and a range of 1.3 to 1.4. Density.

Further, in the first and second aspects of the invention, the polyester film can satisfy the following physical properties. After heating at 150 ° C for 60 minutes, the number of oligopolymer particles precipitated on the surface of the film was 10 (per 10,000 μm ² ), and the area of the oligo polymer particles was 20 μm ² (per 10,000 μm ² ) on average. It was confirmed that in the case where the mobility of the oligomer in the film was within the above range, the rhombic marking phenomenon and the whitening phenomenon were not exhibited.

That is, the primer layer satisfies the following physical properties: a Tg of 60 ° C or more, a coefficient of expansion of 30% or less, a colloid fraction of 95% or more, and a density of 1.3 or more. The amount of the oligomeric polymer particles precipitated on the surface of the film may be 10 or less (per 10,000 μm ² ) and the average particle diameter of the oligomer particles may be 20 μm ² or after heating at 150 ° C for 60 minutes. Less (every 10,000 μm ² ).

In detail, it can be confirmed that the primer layer satisfies the following physical properties: Tg is 60 ° C or more (more specifically, 60 or more and no upper limit is limited), and the expansion coefficient is 30% or less ( More specifically, 0 to 30%), a colloid fraction of 95% or more (more specifically, 95 to 100%), and a density of 1.3 or more (more specifically, 1.3 to 1.4), After heating at 150 ° C for 60 minutes, the structural compactness of the coating and the mobility of the primer layer are lowered, so that the oligopolymer present in the polyester film does not migrate to the surface even if heat and pressure are applied.

In the polyester film according to the present invention, the primer layer is formed by applying a water-dispersible resin composition having an oligomeric polymer barrier property.

In one aspect, when the water-dispersible resin composition is used to form the primer layer, water comprising an acrylic resin copolymerized with a glycidyl group-containing radically polymerizable unsaturated monomer and a water-dispersible polyester-based resin may be used. A dispersible resin composition.

In one aspect, in the water-dispersible resin composition, the solid content weight ratio of the acrylic resin A copolymerized with the glycidyl group-containing radically polymerizable unsaturated monomer to the water-dispersible polyester-based resin B may be 20 to 80. : 80~20% by weight. More preferably, the weight ratio may be 40 to 60: 60 to 40% by weight. The solid content of the water-dispersible polyester-based resin B is less than 20% by weight and the glycidyl group is contained In the case where the solid content of the radical polymerizable unsaturated monomer copolymerized acrylic resin A is more than 80% by weight, as the particle diameter of the emulsion increases, contamination may occur on the in-line coating, and with the polyester base film Adhesion and transparency are reduced. Further, in the case where the solid content of the water-dispersible polyester-based resin B is more than 80% by weight and the solid content of the acrylic resin A copolymerized with the glycidyl group-containing radically polymerizable unsaturated monomer is less than 20% by weight, it is difficult The oligopolymer blocking effect is fully performed.

According to the water-dispersible resin composition of the present invention, an emulsion of the acrylic resin A copolymerized with the aqueous dispersion of the water-dispersible polyester-based resin B and the glycidyl group-containing radically polymerizable unsaturated monomer can be used. Prepared by mixing with each other, and the glycidyl group-containing radically polymerizable unsaturated monomer or copolymerized radically polymerizable unsaturated monomer and glycidol-containing monomer in the aqueous dispersion of the water-dispersible polyester-based resin B can be polymerized alone. The radically polymerized unsaturated monomer is prepared. In this case, a surfactant and a polymerization initiator can be used. Any surfactant and any polymerization initiator can be used without limitation as long as they are generally used for emulsion polymerization. As a specific example of the surfactant, an anionic surfactant, a nonionic surfactant or a non-reactive surfactant may be used, and these surfactants may be used together. As the polymerization initiator, it is a radical polymerization initiator, and a peroxide initiator or a nitrogen compound such as azobisisobutyronitrile or the like can be used.

The water-dispersible resin composition according to the present invention may further comprise an antifoaming agent, a wetting agent, a UV absorber, a preservative, and the like, as needed.

Preferably, any one selected from the compounds represented by the following Chemical Formula 1 or 2 or a mixture thereof is used as a crosslinking agent, whereby the reaction rate can be further increased, and the primer layer can be formed at a low temperature, thereby completely blocking formation. The oligopolymer that leaks out of the primer layer after heating.

(In Chemical Formula 1, A ₁ or A ₃ is a chemical bond or a (C1-C10) alkylene group, respectively, and R ₁ to R ₃ are each independently selected from hydrogen and (C1-C10) alkyl.)

(In Chemical Formula 2, A ₁ to A ₃ are each a (C1-C10) alkylene group and B is a blocking agent.)

The compound of Chemical Formula 1 has a reaction temperature of from 120 to 140 ° C, more specifically about 130 ° C while increasing the reaction rate, so that the reaction starts in the preheating zone during the film formation process of the polyester film. Therefore, the compound reacts with the glycidyl group of the acrylic resin A copolymerized with the glycidyl group-containing radically polymerizable unsaturated monomer, thereby forming a primer coating layer having a more compact structure.

Therefore, in the case of using the compound of Chemical Formula 1, the process of performing the film formation process is carried out in an in-line application process, and thus the process of additionally applying the primer layer is not required after the film is formed, so that the process is performed. Can be simplified. Further, since the thickness of the coating layer can be uniformly formed by stretching after the on-line process, a polyester film having excellent optical properties can be produced.

As a more specific example of the compound of Chemical Formula 1, a compound represented by Chemical Formula 3 can be used.

[Chemical Formula 3]

Since the compound of Chemical Formula 2 exists in a water-dispersed state, after being applied to the film, the compound reacts with water in the preheating zone to be converted into an amine, and then the amine reacts with the isocyanate to carry out self-reaction or The glycidyl group of the radically polymerizable unsaturated monomer copolymerized acrylic resin A reacts with a glycidyl group to form a primer layer having a more compact structure.

In detail, in Chemical Formula 2, A ₁ to A ₃ may be a (C 4 -C 5 ) alkylene group, respectively, and B may be a pyrazolyl blocking agent, and more specifically, may be 3,5-dimethylpyridyl Oxazole.

As a more specific example of the compound of Chemical Formula 2, it may be a compound represented by Chemical Formula 4.

The content of the compound of Chemical Formulas 1 and 2 in the water-dispersible resin composition may preferably be from 0.1 to 10% by weight, more preferably from 0.5 to 2% by weight. In the case where the content is less than 0.1% by weight, the effect of the compound is negligible, and in the case where the content is more than 10% by weight, The coating is too brittle so that cracking occurs on the surface of the primer layer when the polyester film is produced.

In the case of further including the compounds of Chemical Formulas 1 and 2, a polyester film which is maintained at 150 ° C for 60 minutes has a haze change rate (ΔH) of 0.05% or less, more specifically, 0. Up to 0.05%, and scratch resistance and solvent resistance can be further improved.

In the water-dispersible resin composition of the present invention, the water-dispersible polyester-based resin B may be a copolymer of a dicarboxylic acid component including an alkali metal sulfonate compound and a diol component including diethylene glycol.

In more detail, as the dicarboxylic acid component, an aromatic dicarboxylic acid and an alkali metal sulfonate compound can be used, wherein the alkali metal sulfonate compound may contain a content of 6 to 20 mol% based on the total acid component.

As the dicarboxylic acid component, an aromatic dicarboxylic acid such as citric acid, terephthalic acid, dimethyl terephthalic acid, isophthalic acid, dimethyl isononanoic acid, 2,5-dimethyl group can be used. a similar compound such as terephthalic acid, 2,6-naphthalenedicarboxylic acid, biphenyldicarboxylic acid; or an aliphatic dicarboxylic acid such as adipic acid, sebacic acid or the like; or an alicyclic dicarboxylic acid such as A similar compound such as cyclohexanedicarboxylic acid.

As a specific example of the alkali metal sulfonate compound, sulfonic acid terephthalic acid, 5-sulfoisophthalic acid, 4-sulfoisophthalic acid, 4-sulfonaphthalene dicarboxylic acid, 2,7-di can be used. An alkali metal salt of a carboxylic acid or the like, and its content is preferably from 6 to 20 mol%. In the case where the content is less than 6 mol%, the dispersion time of the resin in water may increase, and the dispersibility may decrease, and when the content is more than 20 mol%, the water resistance may be lowered.

As the diol component, diethylene glycol, an aliphatic diol having 2 to 8 carbon atoms or an alicyclic diol having 6 to 12 carbon atoms or the like can be used. As a specific example, ethylene glycol, 1,3-propanediol, 1,2-propanediol, neopentyl glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol, and 1,3- can be used. A similar compound such as cyclohexanedimethanol, 1,2-cyclohexanedimethanol, 1,6-hexanediol, p-xylenediol, triethylene glycol or the like. In this case, it is preferred that the diethylene glycol content is from 20 to 80 mol% based on the total diol component.

The water-dispersible polyester-based resin B may have a number average molecular weight of 1,000 to 50,000 The amount is preferably from 2,000 to 30,000. In the case where the number average molecular weight is less than 1,000, the oligopolymer blocking action is insufficient, and when the number average molecular weight is more than 50,000, the dispersion of the water-dispersible polyester-based resin B is difficult.

As the water-dispersible polyester-based resin B, a water-dispersible material can be prepared by uniformly dispersing the polyester-based resin in water or water containing an aqueous solvent while heating to 50 to 90 °C. In the water-dispersible material prepared as described above, the solid content thereof is preferably 30% by weight, more preferably 10 to 30% by weight. As the aqueous solvent, an alcohol such as methanol, ethanol, propanol or the like, or a similar compound such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol or glycerin can be used.

Next, the acrylic resin A copolymerized with the glycidyl group-containing radically polymerizable unsaturated monomer will be described.

The acrylic resin A copolymerized with the glycidyl group-containing radically polymerizable unsaturated monomer is a homopolymer of a glycidyl group-containing radically polymerizable unsaturated monomer, or a glycidyl group-containing radical polymerizable unsaturated monomer and An interpolymer of another radically polymerizable unsaturated monomer copolymerized with a glycidyl group-containing radically polymerizable unsaturated monomer.

The acrylic resin may contain a glycidyl group-containing radically polymerizable unsaturated monomer as a comonomer, and has a content of 20 to 80 mol% based on the total monomer component. Since the glycidyl group-containing radically polymerizable unsaturated monomer can improve the coating strength of the primer layer and increase the crosslinking density by a crosslinking reaction, leakage of the oligopolymer can be blocked. As a specific example, a similar compound such as glycidyl acrylate, glycidyl methacrylate, glycidyl ether such as allyl glycidyl ether or the like can be used.

Examples of the radically polymerizable unsaturated monomer copolymerized with the glycidyl group-containing radically polymerizable unsaturated monomer may include a vinyl ester, an unsaturated carboxylic acid ester, an unsaturated carboxylic acid decylamine, an unsaturated nitrile, and an unsaturated carboxylic acid. A similar compound such as an acid, an allyl compound, a nitrogen-containing vinyl monomer, a hydrocarbyl vinyl monomer, a vinyl decane compound or the like. As the vinyl ester, a similar compound such as vinyl propionate, vinyl stearate or vinyl chloride can be used. As the unsaturated carboxylic acid ester, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, ethyl methacrylate, butyl methacrylate, monobutyl maleate, and Malay can be used. Similar compounds such as octyl octanoate, monobutyl fumarate, hydroxyethyl methacrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate, hydroxypropyl acrylate, and the like. As the unsaturated carboxylic acid amide, acrylamide, methacrylamide, methylol acrylamide, butoxymethyl acrylamide, or the like can be used. As the unsaturated nitrile, acrylonitrile or the like can be used. As the unsaturated carboxylic acid, acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, maleic acid ester, fumaric acid ester, itaconic acid ester or the like can be used. As the allyl compound, a similar compound such as allyl acetate, allyl methacrylate, allyl acrylate, allyl itaconate, diallyl itaconate or the like can be used. As the nitrogen-containing vinyl monomer, a similar compound such as vinyl pyridine or vinyl imidazole can be used. As the hydrocarbon-based vinyl monomer, a similar compound such as ethylene, propylene, hexane, octene, styrene, vinyl toluene, butadiene or the like can be used. As the vinyl decane compound, dimethylvinyl methoxy decane, dimethyl vinyl ethoxy decane, methyl vinyl dimethoxy decane, methyl vinyl diethoxy decane, γ- can be used. A similar compound such as methacryloxypropyltrimethoxydecane or γ-methylpropenyloxypropyldimethoxydecane.

The water-dispersible resin composition of the present invention may be a water-dispersible or water-soluble composition having a total solid content of 0.5 to 10% by weight, and a glycidyl group-containing radical polymerization in the water-dispersible resin composition. The unsaturated monomer-copolymerized acrylic resin and the water-dispersible polyester-based resin may have a solid content of 0.5 to 10% by weight, the wetting agent may have a content of 0.1 to 0.5% by weight, and have an average particle diameter of 100 to 200 nm. The cerium oxide may contain a content of 0.1 to 1.0% by weight. In view of adjusting the thickness of the coating, a preferred solid content is in the range of 0.5 to 10% by weight.

This wetting agent is used to improve coating properties. As a specific example, a modified decane-based wetting agent such as Q2-5212 (Dow Corning), TEGO WET 250 (ENBODIC), BYK 348 (BYK CHEMIE), or the like can be used, but the present invention is not limited thereto. Preferably, the wetting agent is used in an amount of from 0.1 to 0.5% by weight. Within this range, a desired improvement in coating properties can be achieved.

The cerium oxide having an average particle diameter of 50 to 1000 nm is used for improving the film winding property, and an ACESOL series (Acehitech), a NYACOL series (Nano Technologies), a spherical pulp series (JGC C&C), or the like can be used, but the present invention is not limited thereto. The content of cerium oxide is preferably from 0.1 to 1.0% by weight.

In one aspect of the invention, the polyester base film can be a polyethylene terephthalate film. The polyester base film may have a thickness of 25 to 250 μm.

In the present invention, the primer layer may have a dry coating thickness of 20 to 200 nm. In the case where the dry coating thickness is less than 20 nm, the oligopolymer barrier property cannot be sufficiently achieved, and in the case where the dry coating thickness is more than 200 nm, coating contamination may occur, and it is highly probable that the primer layer is intertwined after the film is wound. The blocking phenomenon of bonding together.

In the present invention, the water-dispersible resin composition is applied by an in-line application method during the production process of the polyester film. That is, in the production of the polyester base film, the water-dispersed resin composition is applied by an in-line application method before the stretching process or between the primary and secondary stretching processes, and during the stretching and heat setting process. The water is heated to evaporate to form a primer layer. The present invention is not limited to the application method as long as the method is known in the art.

According to the upper portion of the polyester film of the present invention, a hard coat layer, an adhesive layer, a light diffusion layer, an indium tin oxide (ITO) layer, or the like can be provided, and even in the case of heating after forming the functional coating layer, Leakage of the oligopolymer can be blocked to maintain optical properties. Therefore, the polyester film according to the present invention can be suitably used as an optical film.

Hereinafter, in order to describe the present invention in more detail, embodiments will be provided. However, the invention is not limited to the embodiments described below.

Hereinafter, physical properties were measured by the following measurement methods.

1) Dry coating thickness of the primer layer

In the entire film coated with the coating composition, 5 points were marked at intervals of 1 m in a direction perpendicular to the machine direction (TD), and the cross section thereof was measured by a scanning electron microscope (SEM, Hitachi S-4300). Further, the marked portion was enlarged at 50000x, the thickness at 30 points in the portion was measured, and the average value was calculated.

2) Haze change rate (△H)

After forming the primer layer,

(1) When forming a double-sided primer layer

The haze of the film before heating and the haze of the film after maintaining at 150 ° C for 60 minutes were measured, and the rate of change was calculated by the following Equation 1.

(2) When forming a single-sided primer layer

The surface opposite to the surface of the primer layer was subjected to corona treatment, and then a hard coating solution (AIKA Corp., Z-711) was applied using Mayer Bar #4, and dried at 80 ° C for 2 minutes, followed by ultraviolet irradiation at 200 mj / Cm ² to form a hard coat layer on the surface.

The haze of the film before heating and the haze of the film after maintaining at 150 ° C for 60 minutes were measured, and the rate of change was calculated by the following Equation 1.

[Equation 1] △H(%)=H _f -H _i

(In Equation 1, H _f is the haze (%) of the film after holding at 150 ° C for 60 minutes, and H _i is the haze of the film before heating.)

3) Average area of oligopolymer particles after heating

After the polyester film was cut into a size of 100 mm × 100 mm and aged in an oven at 150 ° C for 60 minutes, when the aged polyester film was observed using a reflection mode of a microscope (Leica, DM 2500M) of 500x magnification, The area observed for the oligomeric polymer particles was 27,000 μm ² . Surface observation was performed 10 times on the above area, and the shortest length and the longest length of the surface-observed oligopolymer particles were recorded 10 times, thereby calculating the average area of the oligopolymers migrated in the area of 10000 μm ² .

Area of oligo polymer = (shortest length of oligo polymer particles × longest length of oligo polymer particles)

Area of oligopolymer per unit area (10000 μm ² ) = total area of migrated oligopolymer / 2.7

The area of the oligopolymer was averaged after 10 observations.

4) The number of oligopolymer particles after heating

After the polyester film was cut into a size of 100 mm × 100 mm and aged in an oven at 150 ° C for 60 minutes, when the aged polyester film was observed in a reflection mode using a microscope of 500x magnification (Leica, DM 2500M), The area observed for the oligo polymer particles was 27,000 μm ² . The surface was observed 10 times on the above area, and the average value of the number of oligo polymer particles obtained by performing surface observation 10 times was calculated.

Number of oligopolymers per unit area (10000 μm ² ) = (number of oligopolymers per observation / 2.7)

The number of oligopolymers was averaged after 10 observations.

5) Measurement of expansion coefficient, colloid fraction and glass transition temperature (Tg)

15 g of the water-dispersible resin composition prepared in the examples and the comparative examples were placed in a circular container (having a diameter of 80 mm and a height of 15 mm), dried at 80 ° C for 24 hours, and then dried at 120 ° C for 3 hours. It was then aged at 180 ° C for 1 hour. 1 g of the dried coating was collected from the product and then the Tg was measured. Further, the dried coating was immersed in 50 g of distilled water and kept at 70 ° C for 24 hours. The coating was taken out and its coefficient of expansion was measured. The coating was dried at 120 ° C for 3 hours, and the weight was measured to calculate the colloid fraction.

Coefficient of expansion:

After the dried coating (about 1 g) was immersed in distilled water (50 g) and kept at 70 ° C for 24 hours, the coating was taken out and the coefficient of expansion was recorded.

Expansion coefficient = (weight after holding - initial weight) / initial weight × 100

Colloid fraction:

The held coating was dried at 120 ° C for 3 hours and then the weight was recorded.

Colloid fraction = (weight after drying - initial weight) × 100

Tg measurement

The Tg was measured using differential scanning calorimetry (DSC, PerkinElmer DSC7) with a secondary mode of operation. Ten to 11 mg of the dried coating was subjected to Tg measurement using PerkinElmer DSC7 under the following conditions.

First run = temperature is raised from 0 ° C to 200 ° C at a rate of 200 ° C / min, and the temperature is maintained at 200 ° C for a hold time (3 minutes), The temperature was lowered from 200 ° C to -40 ° C at a rate of 200 ° C / min, and then maintained at a temperature of -40 ° C for a hold time (5 minutes).

Second run = Tg measurement was carried out under conditions where the temperature was raised from -40 ° C to 200 ° C at a rate of 20 ° C/min.

[Example 1]

1) Preparation of water-dispersible resin composition 1

16% by weight of KLX-007 adhesive (TAKAMATSU, Japan, 25% solids water-dispersible resin composition), 0.3% by weight of anthrone-based wetting agent (Dow Corning, polyester-oxygen) An alkane copolymer, Q2-5212) and 0.3% by weight of colloidal cerium oxide particles (having an average particle diameter of 140 nm) were added to water and stirred for 2 hours, thereby obtaining a water-dispersible resin composition having a total solid content of 4.6% by weight. 1.

In the KLX-007 binder, the solid content weight ratio (A:B) of the acrylic resin A copolymerized with the glycidyl group-containing radically polymerizable unsaturated monomer and the water-dispersible polyester-based resin B was 50:50.

The acrylic resin contains a glycidyl group-containing radically polymerizable unsaturated monomer as a comonomer, and has a content of 50 mol% based on the total monomer component.

The water-dispersible polyester-based resin contains diethylene glycol (having a content of 50 mol% based on the total diol component) and an alkali metal sulfonate compound (content of 10 mol% based on the total acid component).

2) Manufacture of oligomeric polymer barrier polyester film

After the dehydrated polyethylene terephthalate chips were placed in an extruder and melt extruded, they were rapidly cooled and hardened by a casting roller having a surface temperature of 20 ° C to produce polyethylene terephthalate having a thickness of 2000 μm. Diester tablets. The produced polyethylene terephthalate sheet was stretched 3.5 times in the machine direction (MD) at 80 ° C and cooled to room temperature. Next, the prepared water-dispersible resin composition 1 was applied to both sides of the sheet by a bar coating method, and the temperature was raised to 110 to 150 ° C at a rate of 1 ° C/sec, and the smear was passed through preheating and drying. Stretching in the transverse direction (TD) 3.5 times. Then, heat treatment was carried out in a 5-stage tenter at 235 ° C, and the heat-treated film was loosened by 10% in the machine direction and the transverse direction to be heat-set at 200 ° C, thereby producing a coating on both sides thereof and having a thickness of 188 μm. Biaxially stretched film.

The dried coating layer of the primer layer made of this composition had a thickness of 80 nm. The physical properties of the polyester film obtained as described above are shown in Table 1 below.

[Embodiment 2]

1) Preparation of water-dispersible resin composition 2

16% by weight of KLX-007 binder (TAKAMATSU Co., Ltd., Japan, having a water-dispersible resin composition of 25% solid content), 0.4% by weight of a compound of the following Chemical Formula 3 (based on the solid content of the binder of 10) Parts by weight), 0.3% by weight of an anthrone-based wetting agent (Dow Corning, polyester-aluminoxane copolymer, Q2-5212) and 0.3% by weight of colloidal cerium oxide particles (having an average particle diameter of 140 nm) It was added to water and stirred for 2 hours, thereby obtaining a water-dispersible resin composition 2 having a total solid content of 4.6% by weight.

2) Manufacture of oligomeric polymer barrier polyester film

The dehydrated polyethylene terephthalate pellet was placed in an extruder and melt extruded, rapidly cooled and hardened using a casting roller having a surface temperature of 20 ° C to produce a polyethylene terephthalate having a thickness of 2000 μm. Ethylene glycol tablets. The produced polyethylene terephthalate sheet was stretched 3.5 times in the machine direction (MD) at 80 ° C and cooled to room temperature. Next, the prepared water-dispersible resin composition 2 was applied to both sides of the sheet by a bar coating method, and the temperature was raised to 110 to 150 ° C at a rate of 1 ° C/sec, and the smear was passed through preheating and drying. Stretched 3.5 times in the transverse direction (TD). Then, heat treatment was carried out in a 5-stage tenter at 235 ° C, and the heat-treated film was on-machine. The device and the transverse direction were relaxed by 10% to be heat-set at 200 ° C to produce a biaxially stretched film coated on both sides thereof and having a thickness of 188 μm.

The dried coating layer of the primer layer made of this composition had a thickness of 86 nm. The physical properties of the polyester film obtained as described above are shown in Table 1 below.

[Examples 3 to 6]

A film was produced in the same manner as in Example 1 except that the kind and content of the binder resin and the content of the crosslinking agent were changed as shown in Table 1 below.

In the KLX-008 adhesive (TAKAMATSU, Japan), the solid content weight ratio of the acrylic resin A copolymerized with the glycidyl group-containing radically polymerizable unsaturated monomer to the water-dispersible polyester-based resin B (A: B) ) is 50:50.

The acrylic resin contains a glycidyl group-containing radically polymerizable unsaturated monomer as a comonomer, has a content of 40 mol% based on the total monomer component, and the water-dispersible polyester-based resin contains diethylene glycol (based on total The diol component has a content of 50 mol%) and an alkali metal sulfonate compound (content of 10 mol% based on the total acid component).

In the KLX-030 adhesive (TAKAMATSU, Japan), the solid content weight ratio of the acrylic resin A copolymerized with the glycidyl group-containing radically polymerizable unsaturated monomer to the water-dispersible polyester-based resin B (A: B) ) is 50:50.

The acrylic resin contains a glycidyl group-containing radically polymerizable unsaturated monomer as a comonomer, has a content of 50 mol% based on the total monomer component, and the water-dispersible polyester-based resin contains diethylene glycol (based on total The diol component has a content of 40 mol%) and an alkali metal sulfonate compound (content of 15 mol% based on the total acid component).

[Comparative Example 1]

9.1% by weight of P-3208 binder (having a 44% solids content of water-dispersible resin composition), 0.3% by weight of an oxime-based wetting agent (Dow Corning, polyester-oxime) The polymer, Q2-5212) and 0.3% by weight of colloidal cerium oxide particles (having an average particle diameter of 140 nm) were added to water and stirred for 2 hours, thereby obtaining a water-dispersible resin composition having a total solid content of 4.6% by weight.

The P3208 adhesive (product of Rohm & Haas Co., Ltd.) was a binder containing 40% by weight of methyl methacrylate, 40% by weight of ethyl acrylate and 20% by weight of melamine.

[Comparative Example 2]

20% by weight of H-3 binder (water-dispersible resin composition with 20% solids content), 0.3% by weight of fluorenone-based wetting agent (Dow Corning, polyester-aluminoxane copolymer, Q2) -5212) and 0.3% by weight of colloidal cerium oxide particles (having an average particle diameter of 140 nm) were added to water and stirred for 2 hours, thereby obtaining a water-dispersible resin composition having a total solid content of 4.6% by weight.

The H-3 adhesive (a product prepared by Daichi Kogyo Seiyaku Co., Ltd.) is an aqueous polyurethane adhesive by passing 9% by weight of a polyester-based polyol (polyadipate having a weight average molecular weight of 1,000) Ethylene glycol ester diol), 10% by weight of hexamethylene diisocyanate, 1% by weight of reactive emulsifier with ionic groups (Asahi Denka, Adecaria Soap, polyoxyethylene allyl decyl benzene The glycidyl ether sulfonate (SETM) and 80% by weight of water were prepared by reacting with each other and had a solid content of 20% by weight.

[Comparative Example 3]

16% by weight of a Z-561 binder (having a water-dispersible resin composition having a solid content of 25%), 0.4% by weight of a compound of the following Chemical Formula 2 (based on a solid content of the binder of 10 parts by weight), 0.3 % by weight of an anthrone-based wetting agent (Dow Corning, polyester-aluminoxane copolymer, Q2-5212) and 0.3% by weight of colloidal cerium oxide particles (having an average particle diameter of 140 nm) were added to water and stirred 2 After hours, a water-dispersible resin composition having a total solid content of 4.6% by weight was obtained.

The Z-561 adhesive (product of Goo Chemical Co., Ltd.) is an aqueous polyester adhesive having a solid content of 25% by weight and passing 2,6-naphthalene 40 mol (26 mol%) of dicarboxylic acid, 5 mol (3.3 mol%) of sodium 2,5-dicarboxybenzenesulfonate, 5 mol (3.3 mol%) of dimethylphthalic acid, and mixed in a ratio of 1:1 A mixture of ethylene glycol and 1,4-butanediol was prepared by copolymerization of 100 mol (66.66 mol%).

As shown in Table 1, it can be understood that in Examples 1 to 6 according to the present invention, the haze change rate is remarkably low (0.1% or less), and it can be confirmed that, due to the use of the crosslinking agent, The haze change rate can be further reduced and the area and number of oligopolymers are also significantly reduced.

[Embodiment 7]

1) Preparation of Water-Dispersible Resin Composition 3

As the binder, a binder is used in which the solid content weight ratio (A:B) of the acrylic resin A copolymerized with the glycidyl group-containing radically polymerizable unsaturated monomer and the water-dispersible polyester-based resin B is 40:60. .

An acrylic resin A prepared by copolymerizing 60 mol% of glycidyl acrylate and 40 mol% of vinyl propionate and having a weight average molecular weight of 35,000 was used.

A water-dispersible polyester-based resin B using an acid component using sulfonic acid terephthalic acid (15 mol%) and terephthalic acid (85 mol%) (based on 50 mol% of diethylene glycol) (50 mol%) of the diol component has a content of 50 mol%) and ethylene glycol (50 mol%) polymerized resin having a weight average molecular weight of 14,000.

0.5% by weight (as solid content) of a binder and 0.3% by weight of a decane-based wetting agent (BYK 348, BYK CHEMTE) were added to water and stirred for 2 hours to prepare a total solid content of 0.8% by weight. Water-dispersible resin composition 3.

The above expansion coefficient, colloid fraction and Tg were measured using the prepared water-dispersible resin composition, and the results are shown in Table 2 below.

2) Manufacture of oligomeric polymer barrier polyester film

After the dehydrated polyethylene terephthalate chips were placed in an extruder and melt extruded, they were rapidly cooled and hardened by a casting roller having a surface temperature of 20 ° C to produce polyethylene terephthalate having a thickness of 2000 μm. Diester tablets. The produced polyethylene terephthalate sheet was stretched 3.5 times in the machine direction (MD) at 75 ° C and cooled to room temperature. Next, the prepared water-dispersible resin composition 3 was applied to both sides of the sheet by a bar coating method, and the temperature was raised to 110 to 150 ° C at a rate of 1 ° C/sec, and then the smear was passed through preheating and Drying was stretched 3.5 times in the transverse direction (TD). Then, heat treatment was carried out in a 5-stage tenter at 235 ° C, and the heat-treated film was loosened by 10% in the machine direction and the transverse direction to be heat-set at 200 ° C, thereby producing a coating on both sides thereof and having a thickness of 188 μm. Biaxially stretched film.

The dried coating layer of the primer layer made of this composition had a thickness of 20 nm. The physical properties of the polyester film obtained as described above are shown in Table 3 below.

[Embodiment 8]

Using the same adhesive as in Example 7, 2% by weight (solid content) of the binder, 0.3% by weight of the anthrone-based wetting agent (BYK 348, BYK CHEMTE), and 0.4% by weight of the isocyanate of Chemical Formula 4 The base hardener was added to water and stirred for 2 hours to prepare a water-dispersible resin composition 4 having a total solid content of 2.7% by weight. The above-mentioned expansion coefficient, colloid fraction, and Tg were measured using the prepared water-dispersible resin composition, and the results were shown in Table 2 below.

A biaxially stretched film coated on both sides thereof and having a thickness of 188 μm was produced in the same manner as in Example 7. The dried coating layer of the primer layer made of this composition had a thickness of 50 nm. The physical properties of the polyester film obtained as described above are shown in Table 3 below.

[Embodiment 9]

Using the same adhesive as in Example 7, 2% by weight (solid content) of the binder, 0.3% by weight of the oxime-based wetting agent (BYK 348, BYK CHEMTE), and 1% by weight of the isocyanate of Chemical Formula 4 The base hardener was added to water and stirred for 2 hours, thereby preparing a water-dispersible resin composition 5 having a total solid content of 3.3% by weight. The above expansion coefficient, colloid fraction and Tg were measured using the prepared water-dispersible resin composition, and the results are shown in Table 2 below.

A biaxially stretched film coated on both sides thereof and having a thickness of 188 μm was produced by the same method as in Example 7. The dried coating layer of the primer layer made of this composition had a thickness of 80 nm. The physical properties of the polyester film obtained as described above are shown in Table 3 below.

[Embodiment 10]

1) Preparation of water-dispersible resin composition 6

As the binder, a binder is used in which the solid content weight ratio (A:B) of the acrylic resin A copolymerized with the glycidyl group-containing radically polymerizable unsaturated monomer and the water-dispersible polyester-based resin B is 70:30. .

An acrylic resin A prepared by copolymerizing 60 mol% of glycidyl acrylate and 40 mol% of vinyl propionate and having a weight average molecular weight of 30,000 was used.

A water-dispersible polyester-based resin B using an acid component using sulfonic acid terephthalic acid (15 mol%) and terephthalic acid (85 mol%) (based on 50 mol% of diethylene glycol) (50 mol%) of the diol component has a content of 50 mol%) and ethylene glycol (50 mol%) polymerized resin having a weight average molecular weight of 12,000.

5% by weight (as a solid content) of a binder and 0.3% by weight of a decane-based wetting agent (BYK 348, BYK CHEMTE) were added to water and stirred for 2 hours to prepare a total solid content of 5.3% by weight. Water-dispersible resin composition 6. The above expansion coefficient, colloid fraction and Tg were measured using the prepared water-dispersible resin composition, and the results are shown in Table 2 below.

A biaxially stretched film coated on both sides thereof and having a thickness of 188 μm was produced by the same method as in Example 7 using the produced water-dispersible resin composition 6. The dried coating layer of the primer layer made of this composition had a thickness of 110 nm. The physical properties of the polyester film obtained as described above are shown in Table 3 below.

[Example 11]

Using the same adhesive as in Example 10, 5% by weight (solid content) of a binder, 0.3% by weight of an anthrone-based wetting agent (BYK 348, BYK CHEMTE), and 0.5% by weight of an isocyanate of Chemical Formula 4 The base hardener was added to water and stirred for 2 hours to prepare a water-dispersible resin composition 7 having a total solid content of 5.8% by weight. The above expansion coefficient, colloid fraction and Tg were measured using the prepared water-dispersible resin composition, and the results are shown in Table 2 below.

The water-dispersible resin group produced was used in the same manner as in Example 7. The product 7, a biaxially stretched film coated on both sides thereof and having a thickness of 188 μm was produced. The dried coating layer of the primer layer made of this composition had a thickness of 105 nm. The physical properties of the polyester film obtained as described above are shown in Table 3 below.

[Embodiment 12]

Using the same adhesive as in Example 7, 2% by weight (solid content) of the binder, 0.3% by weight of an anthrone-based wetting agent (BYK 348, BYK CHEMTE), and 0.5% by weight of the compound of Chemical Formula 3 It was added to water and stirred for 2 hours to prepare a water-dispersible resin composition 8 having a total solid content of 2.8% by weight. The above expansion coefficient, colloid fraction and Tg were measured using the prepared water-dispersible resin composition, and the results are shown in Table 2 below.

A biaxially stretched film coated on both sides thereof and having a thickness of 188 μm was produced by the same method as in Example 7 using the prepared water-dispersible resin composition 8. The dried coating layer of the primer layer made of this composition had a thickness of 80 nm. The physical properties of the polyester film obtained as described above are shown in Table 3 below.

[Comparative Example 5]

As the binder, a binder (P3208, Rohm & Haas Co., Ltd.) containing 40% by weight of methyl methacrylate, 40% by weight of ethyl acrylate and 20% by weight of melamine was used.

2% by weight (solid content) of a binder and 0.3% by weight of an anthrone-based wetting agent (BYK 348, BYK CHEMTE) were added to water and stirred for 2 hours to prepare water having a total solid content of 2.3% by weight. Dispersible resin composition 9. The above-mentioned expansion coefficient, colloid fraction, and Tg were measured using the prepared water-dispersible resin composition, and the results are shown below. Table 2 below.

A biaxially stretched film coated on both sides thereof and having a thickness of 188 μm was produced by the same method as in Example 1 using the prepared water-dispersible resin composition 9. The dried coating layer of the primer layer made of this composition had a thickness of 80 nm. The physical properties of the polyester film obtained as described above are shown in Table 3 below.

[Comparative Example 6]

9 wt% polyester-based polyol (polyethylene adipate glycol having a weight average molecular weight of 1000), 10 wt% of hexamethylene diisocyanate, 1 wt% of having ionic groups a reactive emulsifier (Asahi Denka, Adecaria Soap, polyoxyethylene allyl phenyl diglycidyl ether sulfonate (SETM)) and 80% by weight of water are reacted with each other to prepare a solid content of 20% by weight. Waterborne polyurethane adhesive.

4% by weight (solid content) of a binder and 0.3% by weight of an anthrone-based wetting agent (BYK 348, BYK CHEMTE) were added to water and stirred for 2 hours to prepare water having a total solid content of 4.3% by weight. Dispersed resin composition 10. The above expansion coefficient, colloid fraction and Tg were measured using the prepared water-dispersible resin composition, and the results are shown in Table 2 below.

By the same procedure as in Example 7, using the prepared water-dispersible resin composition 10, a biaxially stretched film coated on both sides thereof and having a thickness of 188 μm was produced. The dried coating layer of the primer layer made of this composition had a thickness of 80 nm. The physical properties of the polyester film obtained as described above are shown in Table 3 below.

[Comparative Example 7]

In the absence of solvent, 40 mol (26 mol%) of 2,6-naphthalenedicarboxylic acid, 5 mol (3.3 mol%) of sodium 2,5-dicarboxybenzenesulfonate, and 5 mol of dimethylphthalic acid (3.3) Mol %) and a mixture of ethylene glycol and 1,4-butanediol in a ratio of 1:1, 100 mol (66.66 mol%) were mixed with each other and placed in a reactor at a rate of 1 ° C/min. The esterification reaction was carried out from 170 ° C to 250 ° C while removing by-product water or methanol. Next, by reducing the pressure in the reactor to 1 mmHg while raising the temperature to 260 ° C, a polycondensation reaction is carried out while recovering by-product diol. A polyester resin having an inherent viscosity of 0.4 is provided.

75% by weight of water was added to 25% by weight of the prepared polyester resin and emulsified to prepare an aqueous polyester binder having a solid content of 25% by weight.

4% by weight (solid content) of a binder and 0.3% by weight of an anthrone-based wetting agent (BYK 348, BYK CHEMTE) were added to water and stirred for 2 hours to prepare water having a total solid content of 4.3% by weight. Dispersible resin composition 11. The above expansion coefficient, colloid fraction and Tg were measured using the prepared water-dispersible resin composition, and the results are shown in Table 2 below.

By the same procedure as in Example 7, using the prepared water-dispersible resin composition 11, a biaxially stretched film coated on both sides thereof and having a thickness of 188 μm was produced. The dried coating layer of the primer layer made of this composition had a thickness of 70 nm. The physical properties of the polyester film obtained as described above are shown in Table 3 below.

As shown in Table 2 and Table 3, it can be understood that when the Tg of the primer layer is 60 ° C or more, the expansion coefficient is 30% or less, the colloid fraction is 95% or more, and the density is From 1.3 to 1.4, the number of oligopolymer particles is 10 or less (per 10,000 μm ² ) and its average area size is 20 μm ² or less (per 10,000 μm ² ).

Further, it can be understood that the haze change rate is 0.1% or less.

10‧‧‧ polyester base film

20‧‧‧First primer layer

Claims (19)

A polyester film comprising: a polyester base film; and a primer layer by applying a water-dispersible resin having an oligopolymer barrier property on one surface or both surfaces of the polyester base film The composition is formed; wherein, after the polyester film is placed at 150 ° C for 60 minutes, the haze change rate (ΔH) is 0.1% or less according to the following Equation 1; [Equation 1] ΔH (%) = H _{f -} H _i where H _f is the haze (%) of the film after holding at 150 ° C for 60 minutes, and H _i is the haze of the film before heating. The polyester film according to claim 1, wherein the primer layer has a Tg of 60 ° C or more, a coefficient of expansion of 30% or less, a colloid fraction of 95% or more, and 1.3 to The density of 1.4. The polyester film according to claim 1, wherein the amount of the oligomeric polymer particles precipitated on the surface of the film is 10 or less per 10000 μm ² after heating at 150 ° C for 60 minutes, and 10000μm ² average area as per 20μm ² or less. The polyester film according to claim 1, wherein the water-dispersible resin composition comprises an acrylic resin copolymerized with a glycidyl group-containing radically polymerizable unsaturated monomer, and a water-dispersible polyester. A base resin used as a binder resin. The polyester film according to claim 4, wherein the glycidyl group-containing radically polymerizable unsaturated monomer copolymerized acrylic resin and the water-dispersible polyester are contained in the water-dispersible resin composition. The solid content of the base resin is from 20 to 80:80 to 20% by weight. The polyester film according to claim 4, wherein the water-dispersible resin composition comprises the binder resin and water to have a solid content of 0.5 to 10% by weight. The polyester film according to claim 4, wherein the water-dispersible resin composition further comprises 0.1 to 0.5% by weight of a decane-based wetting agent. The polyester film according to claim 4, wherein the water-dispersible polyester-based resin is a copolymer of a dicarboxylic acid component including an alkali metal sulfonate compound and a diol component including diethylene glycol. . The polyester film according to claim 4, wherein the water-dispersible polyester-based resin contains diethylene glycol in an amount of 20 to 80 mol% based on the total diol component. The polyester film according to claim 4, wherein the water-dispersible polyester-based resin contains an alkali metal sulfonate compound in an amount of 6 to 20 mol% based on the total acid component. The polyester film according to claim 4, wherein the acrylic resin contains a glycidyl group-containing radically polymerizable unsaturated monomer in an amount of 20 to 80 mol% based on the total monomer component as a copolymer body. The polyester film according to claim 4, wherein the water-dispersible resin composition further comprises any one of the compounds represented by Chemical Formula 1 and Chemical Formula 2 or a mixture thereof; In Chemical Formula 1, A ₁ or A ₃ is a chemical bond or a (C1-C10) alkylene group, respectively, and R ₁ to R ₃ are each independently selected from hydrogen and (C1-C10)alkyl; [Chemical Formula 2] In Chemical Formula 2, A ₁ to A ₃ are each a (C1-C10) alkylene group, and B is a blocking agent. The polyester film according to claim 12, wherein the content of any one of the compounds represented by Chemical Formula 1 and Chemical Formula 2 or a mixture thereof is from 0.1 to 10% by weight. The polyester film according to claim 12, wherein the compound of Chemical Formula 1 is the following compound: The polyester film according to claim 1, wherein the polyester-based film is a polyethylene terephthalate film. The polyester film according to claim 1, wherein the polyester-based film has a thickness of from 25 to 250 μm. The polyester film according to claim 1, wherein the primer layer has a dry coating thickness of 20 to 200 nm. The polyester film according to claim 1, wherein the water-dispersible resin composition is applied in an in-line manner during the production of the polyester film. The polyester film according to any one of claims 1 to 18, which is a film for a display.