JP2017518905A - Polyester film and transparent electrode film using the same - Google Patents

Abstract

The present invention relates to a polyester film for application to a touch screen panel and a transparent electrode film using the same. More specifically, the rainbow phenomenon does not occur during hard coating on the end face, the oligomer in the polyester film is blocked from migrating to the surface, and has excellent adhesion under high temperature and high humidity conditions. The present invention relates to a polyester film excellent in adhesion and optical characteristics with a transparent electrode layer and a transparent electrode film using the same.

Description

The present invention relates to a polyester film for application to a touch screen panel and a transparent electrode film using the same. More specifically, the rainbow phenomenon does not occur during hard coating on the end face, the oligomer in the polyester film is blocked from migrating to the surface, and has excellent adhesion under high temperature and high humidity conditions. The present invention relates to a polyester film excellent in adhesion and optical characteristics with a transparent electrode layer and a transparent electrode film using the same.

Optical films have grown with the expansion of the BLU (Back Light Unit) market such as LCD and PDP. Recently, it has been applied to various fields of displays such as a touch screen panel (TSP) such as a mobile phone and a tablet computer.

Such an optical film is required to have excellent transparency and visibility, and a biaxially stretched polyester film excellent in mechanical characteristics and electrical characteristics is used as a base film.

A biaxially stretched polyester film has a low surface hardness and insufficient abrasion resistance or scratch resistance. Therefore, when used as an optical member for various displays, surface damage is likely to occur due to friction or contact with an object. In order to prevent this, a hard coating treatment is applied to the surface of the film. In addition to optical films for ITO (Indium Tin Oxide) transparent electrodes currently applied to TSP applications, new optical films for transparent electrodes such as silver nanowires and metal meshes Hard coating treatment is essential.

On the other hand, in the optical film for transparent electrodes, a primer coating layer is formed as an intermediate layer for improving the adhesion between the polyester film as the base material layer and the hard coating layer.

The primer coating layer is usually used to improve the adhesion between the base material layer and the hard coating layer, and to eliminate the light interference phenomenon (rainbow phenomenon) that occurs due to the large refractive index difference between the hard coating layer and the polyester film. Acrylic resin and urethane resin are used. When such a resin is used alone to form a primer coating layer, the refractive index is around 1.5. This is because the surface refractive index of the biaxially stretched polyester film is 1.64 and the refractive index of the normal hard coating layer is 1.52, which is biased toward the refractive index of the hard coating layer. It is difficult to eliminate the light interference phenomenon caused by the large refractive index difference between the coating layer and the polyester film, that is, the rainbow phenomenon. This causes the problem of eye fatigue and reduced screen visibility.

Therefore, while improving transparency, mechanical properties, and adhesion between the hard coating layer and the base material layer, it prevents rainbow phenomenon and achieves excellent coating properties with conductive coatings during post-processing. It is a situation that requires research and development of optical films that can be made.

In order to solve the above-mentioned problems, the present invention prevents polyester from migrating to the surface without causing a rainbow phenomenon and has excellent adhesion even under high temperature and high humidity conditions. The object is to provide a film.

Moreover, this invention aims at providing the transparent electrode film excellent in the adhesive force and optical characteristic with a transparent conductive layer using the said polyester film.

The present invention for achieving the above object includes a base material layer, a first primer layer laminated on one surface of the base material layer, and a first primer layer laminated on the opposite surface of the first primer layer, A second primer layer of different components; and a hard coating layer formed on the first primer layer.

At this time, the first primer layer and the second primer layer are composed of mutually different components, preferably the difference in glass transition temperature is 10 to 30 ° C., the difference in swelling degree is 10 to 35%, A polyester film having a fraction difference of 10 to 40% is provided.

In the polyester film according to an embodiment of the present invention, the first primer layer and the second primer layer are ester resins in which a dicarboxylic acid component containing a sulfonic acid alkali metal salt compound and a glycol component containing diethylene glycol are copolymerized; Any one selected from a urethane-based resin containing a linear diol having 2 groups and a branched polyol having 3 or more terminal groups; and an acrylate-based resin containing an acrylate-based compound and a melamine-based compound Alternatively, an aqueous dispersion composition containing two or more binder resins, a silicon-based wetting agent, and colloidal silica particles can be included.

In the polyester film according to the embodiment of the present invention, the first primer layer and the second primer layer are composed of 5 to 10% by weight of binder resin, 0.1 to 0.5% by weight of silicon-based wetting agent, and 0.1 of colloidal silica particles. -0.5 wt%, and the balance water.

In the polyester film according to the embodiment of the present invention, the number average molecular weight of the ester resin may be 1,000 to 50,000.

In the polyester film according to an embodiment of the present invention, the urethane resin may have a weight average molecular weight of 10,000 to 20,000 g / mol.

In the polyester film according to the embodiment of the present invention, the acrylate resin may include 10 to 30% by weight of a melamine compound.

In the polyester film according to the embodiment of the present invention, the solid content of the aqueous dispersion composition may be 0.5 to 20% by weight.

In the polyester film according to the embodiment of the present invention, each of the first primer layer and the second primer layer may have a dry coating thickness of 20 to 150 nm.

In the polyester film according to the embodiment of the present invention, the thickness of the base material layer may be 25 to 250 μm.

In the polyester film according to an embodiment of the present invention, the base material layer may be a polyethylene terephthalate film.

The present invention can provide a transparent electrode film in which a transparent conductive layer is formed on the above-described polyester film.

In the transparent electrode film according to the embodiment of the present invention, the transparent conductive layer may be any one or more selected from indium tin oxide, indium zinc oxide, zinc oxide, tin oxide, carbon nanotube, silver nanowire, and metal mesh. Can be.

The transparent electrode film according to the embodiment of the present invention may further include an adhesive layer and a protective film layer on the opposite surface on which the transparent conductive layer is formed.

The polyester film according to the present invention has the advantage that the oligomer in the film is prevented from migrating to the surface without causing a rainbow phenomenon during hard coating on the end face.

In addition, the present invention provides a polyester film having excellent adhesion and optical properties with a transparent electrode layer even under high temperature and high humidity conditions, and using this, a transparent electrode film having excellent optical properties can be provided. There are advantages you can do.

It is the schematic diagram which showed the transparent conductive film by one Embodiment of this invention. It is the schematic diagram which showed the transparent conductive film by one Embodiment of this invention. It is the figure which showed the result by the blocking evaluation method of the Example and comparative example of this invention.

Hereinafter, the polyester film of the present invention and the transparent electrode film produced using the same will be described in detail. The embodiments introduced below are provided as examples so that the idea of the present invention can be sufficiently transmitted to those skilled in the art. In addition, unless otherwise defined, technical terms and scientific terms used herein have the meaning normally understood by those having ordinary knowledge in the technical field to which the present invention belongs. In the drawings, descriptions of known functions and configurations that may obscure the subject matter of the present invention are omitted.

In the present invention, the “primer layer” means a coating film that is applied during or before the stretching process in the production process of the polyester film and formed through the stretching process.

The present invention includes a base layer, a first primer layer and a second primer layer having different components formed on both sides of the base layer, and an upper surface of the first primer layer or the second primer layer. And a hard coating layer provided.

The polyester film according to the present invention includes a base material layer, a first primer layer laminated on one surface of the base material layer, a second primer layer laminated on the opposite surface of the first primer layer, and the first primer. A hard coating layer formed on top of the layer.

The first primer layer and the second primer layer are composed of components having different compositions, have a glass transition temperature difference of 10-30 ° C., a swelling degree difference of 10-35%, and a gel fraction (gel The difference in the fraction) is 10 to 40%.

In the present invention, the glass transition temperature (Tg) is a value measured in 2nd Run mode using a DSC (PerkinElmer DSC 7) apparatus.

In the present invention, the degree of swelling of each primer layer means a value calculated by the following formula 1.

[Formula 1] Swelling degree = (weight after standing-initial weight) / initial weight × 100
(In the above formula, the weight after standing means the weight measured after leaving about 1 g of the dried coating film in 50 g of distilled water and leaving it at 70 ° C. for 24 hours.)

Moreover, the gel fraction of each said primer layer means the value calculated by the following formula 2.

[Formula 2] Gel fraction = (weight after drying−initial weight) × 100
(In the above formula, the weight after drying is measured after dipping about 1 g of the dried coating film in 50 g of distilled water, leaving it at 70 ° C. for 24 hours, and drying the allowed coating film at 120 ° C. for 3 hours. Weight)

In the present invention, the first primer layer and the second primer layer are ester resins in which a dicarboxylic acid component containing a sulfonic acid alkali metal salt compound and a glycol component containing diethylene glycol are copolymerized; One or two or more resins selected from a urethane-based resin containing a linear diol and a branched polyol having 3 or more terminal groups; and an acrylate-based resin containing an acrylate-based compound and a melamine-based compound It is formed using the water dispersion composition containing this.

In the present invention, the ester resin is obtained by copolymerizing a dicarboxylic acid component containing a sulfonic acid alkali metal salt compound and a glycol component containing diethylene glycol.

An aromatic dicarboxylic acid and a sulfonic acid alkali metal salt compound can be used as the dicarboxylic acid component.

Examples of the dicarboxylic acid component include aromatic dicarboxylic acids such as phthalic acid, terephthalic acid, dimethyl terephthalate, isophthalic acid, dimethyl isophthalate, 2,5-dimethylterephthalic acid, 2,6-naphthalenedicarboxylic acid, and biphenyldicarboxylic acid. Aliphatic dicarboxylic acids such as adipic acid and sebacic acid, and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid can be used, but are not necessarily limited thereto.

Examples of the alkali metal salt compound of sulfonic acid include alkali metal salts such as sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfoisophthalic acid, 4-sulfonaphthalene acid-2,7-dicarboxylic acid, Preferably, it can be contained in an amount of 6 to 20 mol% based on the total acid component. When it is used at less than 6 mol%, the dispersion time of the resin in water becomes long and the dispersibility is low, and when it is used at more than 20 mol%, the water resistance can be lowered.

As the glycol component, diethylene glycol, aliphatic having 2 to 8 carbon atoms or alicyclic glycol having 6 to 12 carbon atoms can be used. Examples include ethylene glycol, 1,3-propanediol, 1,2-propylene glycol, neopentyl glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,2 -Cyclohexanedimethanol, 1,6-hexanediol, P-xylene glycol, triethylene glycol and the like can be used, but are not necessarily limited thereto. Under the present circumstances, it is preferable to contain 20-80 mol% of diethylene glycol with respect to all the glycol components.

The ester resin preferably has a number average molecular weight of 1,000 to 50,000, more preferably a number average molecular weight of 2,000 to 30,000. When the number average molecular weight is less than 1,000, the oligomer blocking effect is minute, and when it exceeds 50,000, the water dispersibility may be low.

In the present invention, the urethane resin can be produced by polymerizing a linear diol and a branched polyol having 3 or more terminal groups and an isocyanate monomer. Preferably, what consists of 10-75 weight% of linear diols and 25-90 weight% of branched polyols can be used. When the content of the branched polyol is less than 25% by weight, the degree of swelling and the gel fraction cannot be satisfied, and it is difficult to obtain a coating film having excellent adhesion under high temperature and high humidity conditions. In addition, when the content of the branched polyol exceeds 90% by weight, the viscosity rapidly rises due to excessive gelation, making it difficult to produce an aqueous dispersion composition, and cracks are generated on the surface of the film when it is coated. Defects in the surface appearance can occur.

The branched polyol means a resin having three or more isocyanate functional groups.

As an example of the method for producing the urethane-based resin, by reacting 39 to 45% by weight of polyol, 0.3 to 1.2% by weight of trimethylolpropane, and 50 to 57% by weight of an isocyanate compound, an isocyanate is used as a terminal group. It can be produced by reacting 3 to 4% by weight of an inorganic acid salt and blocking the ionic group of the sulfate at the isocyanate terminal, but is not limited thereto. . When producing by the above production method, a water-dispersible polyurethane resin in which a linear polyurethane resin and a branched polyurethane resin are mixed can be produced, and the linear diol is 10 to 75% by weight and the branched polyol is 25 to 90% by weight. The urethane-type resin which consists of can be manufactured.

When the urethane resin has a weight average molecular weight in the range of 10,000 to 20,000 g / mol, gelation does not occur, water dispersion is possible, and a coating film having excellent physical properties under high temperature and high humidity. Since it is obtained, it is preferable.

The weight average molecular weight can be measured using a GPC-MALS (Multi Angle Light Scattering) system (manufactured by Wyatt) (measured after dissolving the sample in THR, and the calibration curve is polystyrene as a standard sample). The configuration of the MALS system is as follows.

MALS system configuration-GPC; Water 1525 Binary HPLC Pump
-RI detector; Optilab rex
-MALS; Wyatt Dawn 8+
-Column: PLgel 5 μm Mixed-C (7.5 mmΦ × 300 mm) × 2 (Polymer Laboratories)
-Mobile phase: DMF (50 mM LiCl)
-Flow rate: 0.5 mL / min
-Temperature: 50 ° C
-Injection volume: 0.5%, 500 μl

As the polyol, a polyester-based polyol or a polyether-based polyol can be used, and a polyester-based polyol is preferably used. Examples of the polyester-based polyol include a polyol produced by a reaction between a carboxylic acid, sebacic acid, or an acid anhydride and a polyhydric alcohol. The kind of the polyol is not limited, and it is preferable to use a polyester polyol having a weight average molecular weight of 600 to 3,000. The content is preferably 39 to 45% by weight. When used at less than 39% by weight, the molecular weight is small, the primer layer becomes excessively hard, the drawing is difficult, and the coating appearance is not good. On the other hand, if it exceeds 45% by weight, the ILC layer becomes excessively soft and the anti-blocking property may be lowered.

The trimethylolpropane is used for producing a prepolymer having a trifunctional group, and is preferably used at 0.3 to 1.2% by weight. When it is used at less than 0.3% by weight, the crosslinking density is lowered, and the anti-blocking property (Anti-Blocking) may be lowered. Moreover, when using exceeding 1.2 weight%, since a crosslinking density becomes high too much and a drawability worsens, there exists a possibility that coating external appearance may not be good and adhesive force may worsen.

The isocyanate compound is not limited to this, but it is preferable to use hexamethylene diisocyanate. When the content is 50 to 57% by weight, a prepolymer having a trifunctional group can be produced.

As the inorganic acid salt, sodium hydrogen sulfate is preferably used, and the content thereof is preferably 3 to 4% by weight.

In the present invention, the acrylate resin contains an acrylate compound and a melamine compound. At this time, the acrylate resin may include a melamine compound at 10 to 30% by weight.

Examples of the acrylate compounds include methyl acrylate, ethyl acrylate, isopropyl acrylate, n-propyl acrylate, n-butyl acrylate, Isobornyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-propyl methacrylate ), Tert-butyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, cyclohexyl methacrylate (Cyclohexyl methacrylate), isobornyl methacrylate, diethylene glycol monomethyl ether methacrylate, 2-ethylhexyl methacrylate, benzyl methacrylate, 1-naphthylmethyl methacrylate (1-naphthylmethyl methacrylate), 2-naphthylmethyl methacrylate (2-naphthylmethyl methacrylate), 9-anthrylmethyl methacrylate, 1-anthrylmethyl methacrylate, and 2-anthryl One or more selected from the group consisting of methyl methacrylate (2-anthrylmethyl methacrylate) may be mentioned, but the invention is not necessarily limited thereto.

The melamine compound includes at least one selected from the group consisting of hexamethoxymethyl melamine, hexaethoxymethyl melamine, hexapropoxymethyl melamine, hexabutoxymethyl melamine, hexapentyloxymethyl melamine, and hexahexyloxymethyl melamine. Although it is mentioned, it is not necessarily limited to this.

In the present invention, the first primer layer or the second primer layer is an aqueous dispersion composition containing any one or two or more resins selected from the above ester resins, urethane resins, and acrylate resins. It is formed using. As an example, at the time of manufacturing a polyester film, the aqueous dispersion composition is applied and formed by stretching and a heat treatment process.

At this time, the first primer layer and the second primer layer are formed of different components.

Accordingly, the first primer layer and the second primer layer have a glass transition temperature difference of 10-30 ° C., a swelling degree difference of 10-35%, and a gel fraction difference of 10-40%. It is characterized by being. In the present invention, the combination of the glass transition temperature, the degree of swelling, and the gel fraction satisfying the above ranges can prevent the rainbow phenomenon, and the oligomer in the film is prevented from migrating to the surface. In addition, the adhesive force can be improved even under high temperature and high humidity conditions. More preferably, the difference between the glass transition temperature, the degree of swelling, and the gel fraction of the first primer layer and the second primer layer formed of different components is 15 to 25 ° C., respectively. When the degree difference is 15 to 30% and the gel fraction difference is 20 to 40%, the effect of improving physical properties such as blocking and rainbow phenomenon reduction, adhesive strength, adhesion to the conductive layer, and haze characteristics Is more preferable because it can be maximized.

Further, if the glass transition temperature of each primer layer is less than 30 ° C., the primer layer may become soft after coating film formation and the blocking property may be lowered. If the glass transition temperature exceeds 90 ° C., the primer layer Becomes hard and difficult to stretch, and the coating appearance is not good.

In the present invention, the water-dispersed composition contains water in the above-mentioned resin, and may further contain additives such as a wetting agent and a dispersing agent as necessary.

The wetting agent is used to improve the coating property. Specific examples thereof include modified silicon series such as Q2-5212 of Dow Corning, TEGO WET 250 of ENBODIC, and BYK 348 of BYK CHEMIE. A wetting agent or the like can be used, but is not necessarily limited thereto. Moreover, the said wetting agent can be preferably used at 0.1 to 0.5 weight%, and can achieve the target coating property improvement in the said range.

The aqueous dispersion composition may include colloidal silica particles for coating properties and heat resistance processing. As the colloidal silica particles, those having an average particle diameter of 50 to 1,000 nm are preferably used. Moreover, it is preferable that the said colloidal silica particle is contained in 0.1-0.5 weight% in an aqueous dispersion composition in order to show the said effect.

In the present invention, the solid content of the aqueous dispersion composition may be 0.5 to 20% by weight. When the solid content is less than 0.5% by weight, the effect of using it is minute, and when it exceeds 20% by weight, cracks may occur on the surface of the primer layer.

In this invention, it is preferable that the thickness of the said base material layer is 25-250 micrometers, More preferably, it is 50-188 micrometers. If the thickness is less than 25 μm, mechanical properties suitable for an optical film cannot be realized, and if it exceeds 250 μm, the film becomes too thick to be suitable for thinning a display device. Can occur.

The base material layer made of the polyester resin may be made of polyethylene terephthalate (PET) resin alone or may be a copolymer copolymerized with a monomer that can be copolymerized with the polyethylene terephthalate. Preferably, a polyethylene terephthalate homopolymer can be used. At this time, the intrinsic viscosity of the polyethylene terephthalate resin used is preferably 0.5 to 1.0, and more preferably 0.60 to 0.80. In addition, when the intrinsic viscosity of the resin used for the base material layer is less than 0.5, the heat resistance can be reduced, and when it exceeds 1.0, the processing of the raw material is not easy. May be reduced.

The base layer may include any one or more inorganic particles selected from silica, kaolin, and zeolite, and the content thereof is 10 to 10 based on the total weight of the polyester resin of the base layer. It can be included in the range of 1000 ppm.

The dry coating thickness of the primer layer for satisfying the physical properties of the polyester film according to the present invention may be 20 to 150 nm. If the dry coating thickness is less than 20 nm, the oligomer blocking properties are not sufficient and damage such as scratches can be induced. When the thickness exceeds 150 nm, coating unevenness occurs, and the possibility of occurrence of a blocking phenomenon in which primer layers adhere to each other after film winding is increased.

In order to satisfy the physical properties, the primer layer may include one or more inorganic particles selected from silica, kaolin, and zeolite, if necessary, and the content of the primer layer may be dispersed in water. It is preferably 1.0 to 4.0% by weight, more preferably 2.0 to 3.0% by weight, based on the total content of the composition. When the size of the inorganic particles is less than 2.0 μm, the winding property can be lowered due to the protrusion of the particles, and when the size exceeds 4.0 μm, the transparency effect due to the size is reduced and the haze of the product is reduced. Can rise.

The production of a polyester film according to an embodiment of the present invention is not limited to this, but can be obtained by melt-extruding a PET chip with a melt extruder, casting, and biaxially stretching. More specifically, polyester and an additive such as inorganic particles such as silica, kaolin, and zeolite are simultaneously melt extruded with one extruder, cast, cooled, and then biaxially stretched in order.

The water-dispersed composition according to an embodiment of the present invention can be applied by an in-line application method during the manufacturing process of the polyester film. That is, when a polyester film is produced, it can be produced by stretching after being applied by an in-line coating method before stretching, or after primary stretching and before secondary stretching, and can be produced by stretching and secondary stretching and heat setting processes. The water is evaporated by heating, and a primer layer can be formed. The application method is not limited as long as it is a known application method.

The present invention can provide a transparent electrode film in which a transparent conductive layer is formed on the above-described polyester film, that is, on the opposite surface of the end face hard coating layer.

The transparent conductive layer may be selected from the group consisting of indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), tin oxide (SnO2), carbon nanotubes, silver nanowires, and metal mesh. However, it is not necessarily limited to this.

The transparent electrode film may further include an adhesive layer and a protective film layer on the opposite surface on which the transparent conductive layer is formed.

The polyester film of this invention can be shown as an example as FIG.1 and FIG.2. That is, the first primer layer 210 is laminated on the upper surface of the base material layer 100, the hard coating layer 300 is laminated on the upper surface of the first primer layer 210, and the second primer layer is formed on the opposite surface of the first primer layer. 220 is formed. In addition, as shown in FIG. 2, a transparent electrode film in which a transparent electrode layer 400 is formed on one surface of the second primer layer 220 can be provided.

Hereinafter, although an example is given and demonstrated in order to demonstrate this invention concretely, this invention is not limited to the following Example.

Hereinafter, physical properties were measured by the following methods.

(1) Blocking
Using Heat Gradient (manufactured by Toyo Seiki Kogyo Co., Ltd.), set the temperature of each 4 steps under a pressure condition of 0.4 MPa, press for 1 minute, remove the press plate after 1 minute, and confirm the degree did. The difference in each degree was evaluated based on FIG.

-During normal humidity evaluation: Performed in a constant temperature / humidity chamber of 40-50 RH% at 20-25 ° C.
-During humidification evaluation: The film is subjected to 100% RH using an ultrasonic humidifier.

(2) Haze change rate (ΔH)
The film with the hard coating formed on the first primer layer and the second primer layer laminated is placed in a box 3cm high, 21cm wide and 27cm long with the top opened, and heat treated at 150 ° C for 60 minutes. The oligomer was migrated to the surface of the film and allowed to stand for 5 minutes, and then the haze value was measured using a haze meter (Model NDH 5000, manufactured by Nippon Denshoku Industries Co., Ltd.) according to JIS K715 standard. .

The amount of change in haze was calculated by the following formula 3.

[Formula 3]
ΔH (%) = Hf−Hi
(In the above formula, Hf is the haze of the film after being maintained at 150 ° C. for 60 minutes, and Hi is the haze of the film before heating.)

(3) Dry coating thickness of primer layer The full width of the substrate film coated with the coating composition, and specify the 5 points (Point) at 1 m intervals in the vertical direction (TD) of the machine direction After measuring with SEM (Hitachi S-4300), enlarging 50,000 times, measuring 30 points in the section, the average value was calculated.

(4) Rainbow phenomenon a. Measurement 1
After producing optical films with respective compositions on the primer layer, one surface was hard-coated (refractive index 1.52) and the other surface was treated black, and then it was visually confirmed whether or not a rainbow was generated. At the time of visual evaluation, evaluation was performed under a three-wavelength lamp in a dark room.

The evaluation criteria are as follows.

Top: The rainbow is not visible and shows a uniform color Middle: The rainbow appears light and shows a uniform color Bottom: The rainbow appears dark and shows a dark color

b. Measurement 2
After producing optical films of the respective compositions on the primer layer, one surface is hard-coated (refractive index 1.52), the other surface is blackened, and then UV-Visible (CARY 5000) is used for the visible light region. The reflection pattern was measured.

Top: Ripple amplitude is reduced compared to ripple amplitude in other wavelength bands at 500 to 600 nm, and ripple amplitude is 1% or less Medium: Ripple amplitude is reduced compared to ripple amplitude in other wavelength bands at 500 to 600 nm, Ripple amplitude is 3% or less lower: The wavelength band in which the ripple amplitude decreases is not 500 to 600 nm, or the wavelength in which the amplitude decreases does not indicate

(5) Adhesive strength After producing optical films of the respective compositions on the primer layer, the hard coating composition was applied to one surface, and then the adhesive strength at room temperature was evaluated. At the time of evaluation, a cross hatch cutter (YCC-230 / 1) was used to make a cut so that 100 blocks could be formed in a 1 cm × 1 cm block, and an adhesive strength evaluation tape (Nichiban, No. 405) was used. Then, the evaluation was carried out by peeling it three times. At the time of high-temperature and high-humidity evaluation, after high-temperature hot water treatment (100 ° C., 10 minutes), the adhesive force between the hard coating layer and the easy-adhesion layer was evaluated by the above method.

(Production Example 1)
Production of First Water Dispersion Composition for Primer Layer A binder (Rohm and Haas P3208) produced with 40% by weight methyl methacrylate, 40% by weight ethyl acrylate, and 20% by weight melamine was used. After adding 4% by weight of the binder, 0.3% by weight of a silicon-based wetting agent (manufactured by Dow Corning, polyester siloxane copolymer, Q2-5212) and 0.3% by weight of colloidal silica particles having an average particle size of 140 nm to water. The first aqueous dispersion composition was produced by stirring for 2 hours. The primer layer produced using the first aqueous dispersion composition had a glass transition temperature of 42.4 ° C., a swelling degree of 29.6%, and a gel fraction of 90.0.

(Production Example 2)
Preparation of second aqueous dispersion composition for primer layer 2,6-Naphtalene dicarboxly acid 40 mol (26 mol%), sodium 2,5-dicarboxybenzenesulfonate (sodium 2,5- dicarboxylbenzene sulfonate) 5 mol (3.3 mol%), dimethyl terephthalic acid 5 mol (3.3 mol%), bis [4 (2-hydroxyethoxy) phenyl] fluorene (Bis [4 (2-hydroxyethoxy) phenyl] fluorene) ) 20 mol (13.3 mol%), triglyceride (Triglyceride, manufactured by KAO CORPORATION (trade name 85P)) 10 mol (6.6 mol%), ethylene glycol 70 mol (46.6 mol%) in a solvent-free state The mixture is put into a reactor and reacted while raising the temperature from 170 ° C. to 250 ° C. at 1 ° C. per minute to remove water or methanol as a by-product. The esterification reaction proceeds, the temperature is increased to 260 ° C., and the pressure in the reactor is reduced to 1 mmHg, and the polycondensation reaction is performed while collecting the diol as a by-product, whereby the intrinsic viscosity (tetrachloroethane: phenol) A polyester resin having a ratio of 1.0 (measured with a viscosity tube at 35 ° C.) using a mixed solvent of 1: 1 (weight ratio) was produced.

80% by weight of water was added to 20% by weight of the manufactured polyester resin and dispersed therein to prepare a polyester binder having a solid content of 20% by weight. After adding 6% by weight of the binder, 0.3% by weight of a silicon-based wetting agent (manufactured by Dow Corning, polyester siloxane copolymer, Q2-5212) and 0.3% by weight of colloidal silica particles having an average particle size of 140 nm to water. The 2nd water dispersion composition was manufactured by stirring for 2 hours. The primer layer produced using the second aqueous dispersion composition had a glass transition temperature of 63.8 ° C., a swelling degree of 46.3%, and a gel fraction of 55.0.

(Production Example 3)
A water-dispersed polyurethane having a branched polyol content of 50% by weight was manufactured based on the production theory of the third water-dispersed composition for the primer layer. A prepolymer having an isocyanate functional group as a terminal group by reacting 40% by weight of polyol (Polyethyleneadipate Diol), 0.6% by weight of trimethylol propane (Trimethylol Propane) and 55.9% by weight of hexamethylene diisocyanate. (Prepolymer) is produced, and 3.5 wt% of sodium hydrogen sulfate as an ionic group is reacted with isocyanate, which is a terminal functional group of the prepolymer, to have an ionic group and weight. Polyurethane having an average molecular weight of 14,400 g / mol was produced.

A polyurethane binder having a solid content of 20% by weight was produced by dispersing 20% by weight of the produced polyurethane in 80% by weight of water. After adding 4% by weight of the binder, 0.3% by weight of a silicon-based wetting agent (manufactured by Dow Corning, polyester siloxane copolymer, Q2-5212) and 0.3% by weight of colloidal silica particles having an average particle size of 140 nm to water. The third aqueous dispersion composition was produced by stirring for 2 hours. The primer layer produced using the third aqueous dispersion composition had a glass transition temperature of 52.6 ° C., a swelling degree of 61.7%, and a gel fraction of 80.0.

Example 1
The polyethylene terephthalate chip from which moisture was removed was put into an extruder and melt-extruded, and then rapidly cooled and solidified with a casting drum having a surface temperature of 20 ° C. to produce a polyethylene terephthalate sheet having a thickness of 2000 μm. The manufactured polyethylene terephthalate sheet was stretched 3.5 times in the machine direction (MD) at 80 ° C. and then cooled to room temperature. Thereafter, a second primer layer is formed on one side of the sheet by a bar coating method using the first aqueous dispersion composition produced in Production Example 1, and a production example is formed on the other side of the sheet. A first primer layer was formed by a bar coating method using the second aqueous dispersion composition prepared in 2. Thereafter, the temperature was raised by 1 ° C. per second to 110 to 150 ° C., preheated and dried, and stretched 3.5 times in the transverse direction (TD). Thereafter, heat treatment was carried out at 230 ° C. with a five-stage tenter and heat-fixed by relaxing 10% in the longitudinal and transverse directions at 200 ° C. to produce a 188 μm biaxially stretched film coated on both sides. The dry application thickness of the first primer layer was 80 nm, and the dry application thickness of the second primer layer was 80 nm. A hard coating layer having a surface hardness of 2H and a thickness of 3 μm after drying is formed on the first primer layer by a UV curing process, and a transparent electrode layer (silver (Ag) (Ag) is formed on the second primer layer. ) Nanowire layer) was formed.

(Example 2)
The polyethylene terephthalate chip from which moisture was removed was put into an extruder and melt-extruded, and then rapidly cooled and solidified with a casting drum having a surface temperature of 20 ° C. to produce a polyethylene terephthalate sheet having a thickness of 2000 μm. The manufactured polyethylene terephthalate sheet was stretched 3.5 times in the machine direction (MD) at 80 ° C. and then cooled to room temperature. Thereafter, a second primer layer is formed on one side of the sheet by a bar coating method using the first aqueous dispersion composition produced in Production Example 1, and a production example is formed on the other side of the sheet. A first primer layer was formed by a bar coating method using the third aqueous dispersion composition prepared in 3. Thereafter, the temperature was raised by 1 ° C. per second to 110 to 150 ° C., preheated and dried, and stretched 3.5 times in the transverse direction (TD). Thereafter, heat treatment was carried out at 230 ° C. with a five-stage tenter and heat-fixed by relaxing 10% in the longitudinal and transverse directions at 200 ° C. to produce a 188 μm biaxially stretched film coated on both sides. The dry application thickness of the first primer layer was 80 nm, and the dry application thickness of the second primer layer was 80 nm. A hard coating layer having a surface hardness of 2H and a thickness of 3 μm after drying is formed on the first primer layer by a UV curing process, and a transparent electrode layer (silver (Ag) (Ag) is formed on the second primer layer. ) Nanowire layer) was formed.

(Example 3)
The polyethylene terephthalate chip from which moisture was removed was put into an extruder and melt-extruded, and then rapidly cooled and solidified with a casting drum having a surface temperature of 20 ° C. to produce a polyethylene terephthalate sheet having a thickness of 2000 μm. The manufactured polyethylene terephthalate sheet was stretched 3.5 times in the machine direction (MD) at 80 ° C. and then cooled to room temperature. Thereafter, a second primer layer is formed on one surface of the sheet by a bar coating method using the second aqueous dispersion composition produced in Production Example 2, and a production example is formed on the opposite surface of the sheet. A first primer layer was formed by a bar coating method using the third aqueous dispersion composition prepared in 3. Thereafter, the temperature was raised by 1 ° C. per second to 110 to 150 ° C., preheated and dried, and stretched 3.5 times in the transverse direction (TD). Thereafter, heat treatment was carried out at 230 ° C. with a five-stage tenter and heat-fixed by relaxing 10% in the longitudinal and transverse directions at 200 ° C. to produce a 188 μm biaxially stretched film coated on both sides. The dry application thickness of the first primer layer was 80 nm, and the dry application thickness of the second primer layer was 80 nm. A hard coating layer having a surface hardness of 2H and a thickness of 3 μm after drying is formed on the first primer layer by a UV curing process, and a transparent electrode layer (silver (Ag) (Ag) is formed on the second primer layer. ) Nanowire layer) was formed.

(Comparative Example 1)
The same method as in Example 1 was performed except that only the first aqueous dispersion composition was used when forming the first primer layer and the second primer layer.

(Comparative Example 2)
The same method as in Example 1 was performed except that only the second aqueous dispersion composition was used when forming the first primer layer and the second primer layer.

(Comparative Example 3)
It replaced with having used the 1st water dispersion composition in the comparative example 1, and performed by the method similar to Example 1 except having used the 3rd water dispersion composition.

As shown in Table 1, Examples 1-3 according to the present invention exhibited excellent anti-blocking performance. Specifically, in Example 1, no blocking phenomenon occurred until 140 ° C. Moreover, Example 2 and 3 maintained the antiblocking performance which was excellent to 120 degreeC or 100 degreeC, respectively. On the other hand, in Comparative Example 2, a blocking phenomenon occurred at 120 ° C., and in Comparative Example 3, a blocking phenomenon occurred at 100 ° C. In addition, as shown in Table 2, Example 1 according to the present invention achieved excellent anti-blocking performance, but did not generate rainbow phenomenon and had excellent adhesion. On the other hand, although Comparative Example 1 realized an excellent anti-blocking effect, a rainbow phenomenon occurred and the adhesive force was significantly inferior to that of Example 1. Moreover, as a result of comparing the adhesive force between the primer layer and the transparent conductive layer, as shown in Table 3, Example 1 according to the present invention was superior in the adhesive force as compared with Comparative Examples 2 and 3, and the haze change rate. There was almost no difference.

Although the preferred embodiments of the present invention have been described above, it is obvious that the present invention can be variously modified and equivalents, and can be similarly modified and applied in the same manner. Accordingly, the above description should not be taken as limiting the scope of the invention which is determined by the limitations of the appended claims.

100 base material layer 210 first primer layer 220 second primer layer 300 hard coating layer 400 transparent electrode layer

Claims (13)

A base material layer;
A first primer layer laminated on one surface of the base material layer;
A second primer layer laminated on the other surface corresponding to one surface of the base material layer;
A hard coating layer formed on the first primer layer, wherein the first primer layer and the second primer layer have a glass transition temperature difference of 10 to 30 ° C. and a swelling degree difference of 10 A polyester film having a gel fraction difference of ˜35% and a gel fraction difference of 10˜40%. The first primer layer and the second primer layer are ester resins in which a dicarboxylic acid component containing a sulfonic acid alkali metal salt compound and a glycol component containing diethylene glycol are copolymerized; a linear diol and three or more end groups One or more binder resins selected from urethane resins produced by polymerizing certain branched polyols and isocyanate monomers; and acrylate resins containing acrylate compounds and melamine compounds. The polyester film according to claim 1, comprising an aqueous dispersion composition comprising, a silicon-based wetting agent, and colloidal silica particles. The first primer layer and the second primer layer are composed of a binder resin of 5 to 10% by weight, a silicon-based wetting agent of 0.1 to 0.5% by weight, colloidal silica particles of 0.1 to 0.5% by weight, and the remainder The polyester film according to claim 1, comprising water. The polyester film according to claim 1, wherein the ester-based resin has a number average molecular weight of 1,000 to 50,000. The polyester film according to claim 1, wherein the urethane-based resin has a weight average molecular weight of 10,000 to 20,000 g / mol. The polyester film according to claim 1, wherein the acrylate resin contains 10 to 30% by weight of a melamine compound. The polyester film according to claim 1, wherein the solid content of the aqueous dispersion composition is 0.5 to 20% by weight. The polyester film according to claim 1, wherein each of the first primer layer and the second primer layer has a dry coating thickness of 20 to 150 nm. The polyester film according to claim 1, wherein the base material layer has a thickness of 25 to 250 μm. The polyester film according to claim 1, wherein the base material layer is a polyethylene terephthalate film. The transparent electrode film in which the transparent conductive layer was formed on the polyester film as described in any one of Claims 1 thru | or 10. The transparent electrode film according to claim 11, wherein the transparent conductive layer includes any one or more selected from indium tin oxide, indium zinc oxide, zinc oxide, tin oxide, carbon nanotubes, silver nanowires, and metal mesh. . The transparent electrode film according to claim 11, further comprising an adhesive layer and a protective film layer on the opposite surface on which the transparent conductive layer is formed.