KR101798745B1 - Polyester film for optical use - Google Patents

Abstract

The present invention relates to an optical polyester film, and more particularly to a polyester film for optical use, which is excellent in optical properties as well as optical polyester film having a primer layer and after uniform processing of a functional optical coating such as a prism, An optical film which has not only a normal temperature and humidity resistance but also an excellent coating property and prevents the drop off phenomenon of the post-application coating layer from the polyester base film and secures the productivity of the film, To a polyester film for use in the present invention.

Description

POLYESTER FILM FOR OPTICAL USE

The present invention relates to an optical polyester film, and more particularly to a polyester film for laminated optics applied to films mounted inside a touch panel, LCD, PDP or the like, Such as a substrate and a prism, a lens, or a hard coating, which is easy to have such uniform adhesiveness after the post-processing.

The polyester film is excellent in dimensional stability, thickness uniformity and optical transparency, and is widely used for various industrial materials as well as display devices. Of these, plastic film for optical use is a plastic film used for optical use, more specifically, a plastic film is widely used as a component of a display device, for example, a PDP (Plasma Display) or an LCD (liquid crystal display) A polyester film is used when optical transparency is required, and a polyimide film is mainly used when durability and heat resistance are required. In particular, biaxially stretched polyester films are excellent in dimensional stability, thickness uniformity and optical transparency, and are used as base films in various industrial fields.

The optical polyester film is used as a substrate film for various purposes by applying various resins through a post-treatment, and a resin used for post-processing is usually a UV curable resin. Therefore, a method of applying a primer coating layer on the surface of a polyester film is generally used industrially in order to uniformly adhere the UV curable resin coating layer and the optical polyester film applied through post-processing.

In general, in the case of an optical polyester film subjected to a primer processing treatment, a copolymerized polyester resin (binder) having excellent adhesion to a polyester base material has often been used as a primer layer. However, There is a problem that the adhesiveness to the polyester base material is sufficient but the heat resistance and the adhesion of the moisture resistance are poor and the adhesiveness is very poor when the prism processing layer, the lens processing layer, the antireflection layer or the hard coating layer .

In order to solve this problem, acrylic or polyurethane type binder has recently been introduced to further improve the adhesion of the functional UV curable resin, which is excellent in heat resistance and moisture resistance, and used in post-processing, Or a polyurethane-based binder has been developed much. Particularly, in the case of the polyurethane-based binder, since the functional group is generally diol (OH-R-OH), it is known that the substitution with other polymer facilitates the change of physical properties and control,

However, in the case of acrylic or polyurethane based binders, even when the binder has excellent heat resistance and adhesion to UV cured resin at the time of post-processing, adhesion to various polyester laminated films as a base layer is insufficient, There is a problem that the layer is separated from the polyester base layer. Therefore, the optical polyester film used as the base film is required to have a post-processing operation characteristic, particularly a uniform adhesion force with water used in post-processing. Thus, the technique of maintaining a uniform adhesion force is effective in reducing defective rate, It is necessary to formulate.

Korea Patent Publication No. 2014-0038990 Korea Patent Publication No. 2014-0032442 Korea Patent Publication No. 2010-0125302

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems, and it is an object of the present invention to provide an optical polyester film having a primer layer as well as excellent optical properties, and a prism, a lens or a functional optical coating And has excellent coating properties as well as uniform coating at room temperature and humidity after processing. It prevents the drop off of the post-coating layer from the polyester base film and secures productivity, life and quality of the film through reduction of defective rate of product To provide an optical polyester film which can be used as an optical film.

These and other objects and advantages of the present invention will become more apparent from the following description of a preferred embodiment thereof.

The above object is achieved by a polyester film comprising a polyester base film and a primer layer formed on one or both sides of the base film, wherein the primer layer has a molecular weight of from 5,000 to 50,000 having a first binder resin having an urethane group and an acryloyl reactor And a primer composition comprising a mixed resin composed of a second binder resin and at least one crosslinking agent.

The first binder resin is a water-dispersed polyurethane resin, and the second binder resin has a basic skeleton that is selected from the group consisting of a polyester-based polymer, a polyurethane-based polymer, and a polyacrylic polymer .

Preferably, the cross-linking agent is one or at least two or more selected from the group consisting of oxazoline-based, carbodiimide-based, epoxy-based, aziridine-based and melamine-based ones.

Preferably, the primer layer is applied with a coating liquid comprising 20 to 60 parts by weight of the first binder resin, 30 to 60 parts by weight of the second binder resin, and 1 to 35 parts by weight of the cross-linking agent.

Preferably, the primer layer is applied with a coating liquid containing 20 parts by weight of the first binder resin, 60 parts by weight of the second binder resin, and 20 to 30 parts by weight of the carbodiimide-based crosslinking agent.

Preferably, the thickness of the primer layer is 0.02 to 0.3 mu m.

Preferably, the adhesive force between the primer layer and the coating layer composed of the acrylic resin formed on the primer layer is 95% or more after a test of wettability within 360 hours at 65 ° C and 95% humidity.

According to the present invention, not only is it possible to obtain a polyester film for optical use having a primer layer and a functional optical coating such as a prism, a lens or a hard coating as a post-processing resin, And the like.

Further, the present invention has the effect of preventing the drop off phenomenon of the post-application coating layer when used as a polyester base film and securing productivity, lifetime and high quality of the film by reducing the defect rate of the product.

However, the effects of the present invention are not limited to the above-mentioned effects, and other effects not mentioned can be clearly understood by those skilled in the art from the following description.

1 is a sectional view of an optical polyester film including a primer layer after primary processing according to the present invention.
FIG. 2 is a cross-sectional view of a polyester film for optical use including a functional coating layer after secondary processing according to the present invention. FIG.

Hereinafter, the present invention will be described in detail with reference to embodiments and drawings of the present invention. It will be apparent to those skilled in the art that these embodiments are provided by way of illustration only for the purpose of more particularly illustrating the present invention and that the scope of the present invention is not limited by these embodiments .

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In case of conflict, the present specification, including definitions, will control. Also, although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described herein.

In describing and / or claiming the present invention, the term "copolymer" is used to refer to a polymer formed by copolymerization of two or more monomers. Such copolymers include binary copolymers, terpolymers, or higher order copolymers.

The optical polyester film according to one aspect of the present invention comprises a polyester base film and a primer layer formed on one or both sides of the base film, wherein the primer layer comprises a first binder resin (UV curable resin) having a urethane group, And a primer composition comprising a mixed resin composed of a second binder resin (UV reactive resin) having a molecular weight of 5,000 to 50,000 and an acryloyl reactor and at least one crosslinking agent.

Here, the acryloyl reactor of the second binder resin is represented by the following general formula (1).

[Chemical Formula 1]

Here, R is a polyester resin, a polyurethane resin or a polyacrylic resin. That is, the basic skeleton of the second binder resin is selected from a polyester resin, a polyurethane resin or a polyacrylic resin.

The optical polyester film according to the embodiment of the present invention is different from the conventional optical polyester film in that two types of binder resins, that is, a first binder resin and a second binder resin, are applied to a primer layer, The resin is characterized in that at least one of the UV-reactive functional groups is acryloyl. That is, in order to improve the adhesive strength between the polyester base film and the ultraviolet curing type coating layer to which the secondary finishing treatment is applied, the present invention is characterized in that a coating solution prepared by further blending a polymer resin having an acryloyl Thereby forming a primer coating layer. This is intended not only to maintain sufficient adhesion between the substrate and the ultraviolet curing type coating layer, but also to ensure a uniform and excellent adhesive force even in the evaluation of moisture resistance at high temperature and high humidity.

According to one embodiment of the present invention, a primer layer is placed on a polyester base film stretched by at least one axis, and a primer composition (coating liquid) for forming a primer layer is a mixture resin obtained by mixing two kinds of binder resins Configure it as default.

One of the two kinds of binder resins is a water-dispersible urethane-based polymer resin as a first binder resin having a urethane group,

 The other binder resin of the two kinds of binder resins is a second binder resin having an acryloyl group and having a molecular weight of 5,000 to 50,000 and is selected from the group consisting of a polyester-based polymer, a polyurethane-based polymer, and a polyacrylic polymer The polymer has a basic skeleton, alone or in combination.

That is, the optical polyester film according to one embodiment of the present invention is characterized in that when a second binder resin is used as a primer layer constituent, a polymer binder selected from at least one of polyester resin, polyurethane resin and polyacrylic resin is used as a basic skeleton .

In order to form a coating layer using a polyurethane binder, an ester or carbonate type is generally used as a polyol having two or more functionalities, and aliphatic isocyanate is used as an isocyanate, and a composition containing a diol or a diamine as a chain extender is used as a coating liquid do.

In order to form a coating layer using a polyester-based binder, a coating liquid containing a dicarboxylic acid component and a branched glycol component is usually used.

In order to form a coating layer using a polyacrylic binder, a coating liquid containing a mixture of methyltetraacrylate, methacrylate, butyl acrylate, acrylic acid and the like is usually used. The binder component used in the coating liquid preferably has a Tg of 20 to 100 캜.

The second binder resin having an acryloyl-based reactor may also include at least one of the reactor structures, which may include a UV-curing resin located on the primer layer through a primary thermosetting system and a second- And can be cured together through an ultraviolet curing system. Here, it is generally preferable to select an acrylic resin as the functional UV reactive resin to be used in post-processing.

The second binder resin contains a UV reactive functional group structure having a specific functional group at the terminal of the second binder resin to participate in the UV curing reaction such as a UV curable resin placed on the base film at the time of post- .

More specifically, in the present invention, the coating liquid constituting the primer layer is prepared by dissolving the water-dispersible binder resin in a solvent such as water, The mixing of the first binder resin and the second binder resin results in stable molecular orientation in which molecules are regularly arranged in the solvent depending on the hydrophilic property and the hydrophobic property. As a result, the two kinds of binder resins exhibit a molecular orientation and specific functional moieties such as acryloyl have directionality.

The present invention is characterized by containing a UV-reactive functional group structure in a specific functional group having a directionality, and it is possible to improve the adhesion with a conventional UV-curable resin by participating in UV curing reaction like a UV curable resin placed on a base film at post- And can be efficiently improved.

In one embodiment of the present invention, the cross-linking agent of the primer composition is one or at least two or more selected from the group consisting of oxazoline-based, carbodiimide-based, epoxy-based and melamine-based curing agents and that the curing reaction by the thermosetting system proceeds . Suitably, two types of curing agents are preferably applied.

The oxazoline crosslinking agent can be used without limitation as long as it is an oxazoline group-containing monomer or a compound having at least one oxazoline group-containing monomer and an oxazoline group as a functional group such as a polymer compound in which at least one other monomer is copolymerized. Examples of the oxazoline crosslinking agent include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2- 2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline or 2-isopropenyl-5-ethyl-2-oxazoline, And the like can be used. Other comonomers may be copolymerized with the polymer compound. Examples of such monomers include alkyl (meth) acrylates, amide group-containing monomers, unsaturated nitrile monomers, vinyl ester monomers, vinyl ether monomers, -Unsaturated monomers, and?,? - unsaturated aromatic monomers.

As the carbodiimide crosslinking agent, a carbodiimide compound or a polycarbodiimide may be used, but it is not limited thereto. The carbodiimide compound refers to a compound having two or more carbodiimide groups (-N═C═N-) in a molecule and includes, for example, those described in JP-A-10-316930 and JP-A-11-140164 As organic polyisocyanates, particularly preferably organic diisocyanates, are produced as the main starting materials for synthesis. The diisocyanates include hexamethylene diisocyanate, hydrogenated xylylene diisocyanate, xylylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 1,12-diisocyanate dodecane, norbornane diisocyanate and Is selected from 2,4-bis- (8-isocyanate octyl) -1,3-dioctylcyclobutane, 4,4'-dicyclohexylmethane diisocyanate, tetramethylxsilylene diisocyanate, and isophorone diisocyanate One or more diisocyanates may be mentioned.

Examples of the epoxy-based crosslinking agent include a polyepoxy compound, a diepoxy compound, and a glycidyl amine compound as the epoxy compound, and examples of the polyepoxy compound include sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether , Pentaerythritol polyglycidyl ether, dislycerol polyglycidyl ether, triglycidyl tris (2-hydroxyethyl) isocyanate, glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, diepoxy As the compound, for example, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, resorcin diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, Propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, polytetramethylene glycol diglycidyl ether, monoepoxy Examples of the compound include allyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, and glycidyl amine compounds include N, N, N ', N'-tetraglycidyl- 1,3-bis (N, N-diglycidylamino) cyclohexane, and the like.

The aziridine crosslinking agent may be at least one selected from the group consisting of N, N'-toluene-2,4-bis (1-aziridine carboxamide), N, N'-diphenylmethane-4,4'-bis (1-aziridinecarboxide ), Triethylene melamine, bisisopropanoyl-1- (2-methyl aziridine), and tri-1-aziridinyl phosphine oxide.

Examples of the melamine crosslinking agent include, but not limited to, methylolmelamine derivatives obtained by condensing melamine, melamine and formaldehyde, methylolmelamine, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butanol, Butanol and the like can be used. The term " functional group " means a group having an imino group, a methylol group or an alkoxymethyl group such as methoxymethyl group or butoxymethyl group in one molecule, and includes imino group type methylated melamine resin, methylol group type melamine resin, methylol group type methylated melamine resin, Fully alkylated methylated melamine resin.

Further, particles may be added to the film raw material so as to have functions such as running property, weather resistance and heat resistance of the film, but sufficient attention should be paid to the addition amount and the material so as not to make the film transparent. The addition amount is preferably an extremely small amount, more preferably not added. As for the running property of the film, it is preferable to assist by adding particles of the laminated film.

The primer layer according to an embodiment of the present invention is composed of 20 to 60 parts by weight of a first binder resin and 20 to 60 parts by weight of a second binder resin having a molecular weight of 5,000 to 50,000 and having an acryloyl reactor of formula . And one or at least two or more selected from the group consisting of an oxazoline series, a carbodiimide series, an epoxy series, an aziridine series and a melamine series is selected as a curing agent, and a coating liquid to which 1 to 35 parts by weight of the coating liquid is added is formed , And the thickness of the primer layer thus formed is preferably 0.02 to 0.3 mu m.

More preferably, the coating liquid preferably contains 20 parts by weight of the first binder resin, 60 parts by weight of the second binder resin and 20 to 30 parts by weight of the carbodiimide-based crosslinking agent. In this case, And thus it can be confirmed that it is excellent.

In the present invention, it is preferable that the surface of the base film on which the primer layer is formed has a total light transmittance of 80% or more and a haze value of 0.4 to 2.4%.

Further, the adhesion between the primer layer and the coating layer composed of the acrylic resin as the UV-reactive resin is characterized by being at least 95% after the wet test in 360 hours at 65 ° C and 95% humidity. The optical polyester film according to the present invention has a design of a primer layer so that the adhesive force with the coating layer can be enhanced even after processing such as a prism, a lens or a hard coating. And is at least 95% after a 360-hour moisture resistance test.

Hereinafter, the structure and effect of the present invention will be described in more detail with reference to examples and comparative examples. However, this embodiment is intended to explain the present invention more specifically, and the scope of the present invention is not limited to these embodiments.

[Examples 1 to 18]

The coating liquid to be composed of the primer layer in the present invention having the constitution of the coating liquid of the following Table 1 was prepared by mixing the first binder resin aqueous dispersion liquid containing 30% by weight of water-dispersed polyurethane resin and 70% As a second binder resin having a molecular weight of 10,000 and a reactor having the general formula (1), a second binder resin aqueous dispersion comprising 30% by weight of an acrylic binder resin and 70% by weight of water and a second binder resin aqueous dispersion comprising a mixture of oxazoline, carbodiimide and epoxy One kind is selected as a curing agent and 10 to 30 parts by weight, and the thickness of the applied primer layer is 0.02 탆.

In this embodiment, toluylene diisocyanate, ethylene glycol, and ethylenediamine were respectively formed in a molar ratio of 20: 17: 14 as the first binder resin, and the acrylic binder resin as the second binder resin was ethyl acrylate Methyl methacrylate and methylol acrylamide were formed in a molar ratio of 70: 15: 5, and the ratio of acryloyl to the entirety was 10% by weight.

In this embodiment, the oxazoline-based curing agent was an acrylic polymer having an oxazoline group and a polyalkylene oxide chain, and was abbreviated as "oxazoline-based ". The carbodiimide-based curing agent used was a curing agent prepared by using hexamethylene diisocyanate, which is an organic diisocyanate, and was abbreviated as "carbodiimide-based". The epoxy-based curing agent was a polyhydroxyalkane-polyglycidylether And was abbreviated as "epoxy system".

In addition, 0.1 part by weight of the fluorine surfactant aqueous dispersion was added to the coating liquid of all the Examples to increase the film coating property, and 0.05 part by weight of silica particles having an average particle size of 300 nm was added to improve the film running property.

In this embodiment, an industrial production method of a polyester film used as a base film before applying a primer coating solution is as follows.

The polyethylene terephthalate resin pellets were dried at 135 DEG C for 6 hours under reduced pressure (1.3 hPa), and then extruded by an extruder. The extruded pellets were melt extruded at about 280 DEG C onto a sheet, To obtain a casting film having a thickness of 1024 mu m. Next, the casting film was heated to 100 DEG C in a heated roll group and an infrared heater, and then stretched at a 3.2-fold stretching ratio in the longitudinal direction by a roll group having a peripheral speed to obtain a uniaxially oriented PET film, which was used as a substrate . Subsequently, the film was gripped at the end with a clip, introduced into a hot air region, and dried. Thereafter, stretching was carried out at 130 占 폚 in the transverse direction at 3.2 times the stretching ratio, followed by heat setting at 240 占 폚, and then lateral relaxation at 3 占 폚 at 200 占 폚. Thus, an optical biaxially oriented polyester base film having a thickness of 100 탆 was obtained.

In Examples 1 to 27, the coating liquid for forming the primer layer in the production process of the polyester base film was stretched in the longitudinal direction at a stretching ratio of 3.2 times, and then the reverse side of the uniaxially oriented PET film was subjected to a reverse roll method in which the solid content weight was 0.08 g / m < 2 >.

As shown in the following Table 1, the proportions of the polymer binder resin and the curing agent were controlled and the summary names were abbreviated as described above. In all the examples, the total molecular weight was adjusted to be 10,000 g / mol or less.

division The first binder resin The second binder resin Hardener Weight portion Weight portion Kinds Weight portion Example 1 60 20 Oxazoline system 10 Example 2 60 20 Oxazoline system 20 Example 3 60 20 Oxazoline system 30 Example 4 60 20 Carbodiimide system 10 Example 5 60 20 Carbodiimide system 20 Example 6 60 20 Carbodiimide system 30 Example 7 60 20 Epoxy system 10 Example 8 60 20 Epoxy system 20 Example 9 60 20 Epoxy system 30 Example 10 40 40 Oxazoline system 10 Example 11 40 40 Oxazoline system 20 Example 12 40 40 Oxazoline system 30 Example 13 40 40 Carbodiimide system 10 Example 14 40 40 Carbodiimide system 20 Example 15 40 40 Carbodiimide system 30 Example 16 40 40 Epoxy system 10 Example 17 40 40 Epoxy system 20 Example 18 40 40 Epoxy system 30 Example 19 20 60 Oxazoline system 10 Example 20 20 60 Oxazoline system 20 Example 21 20 60 Oxazoline system 30 Example 22 20 60 Carbodiimide system 10 Example 23 20 60 Carbodiimide system 20 Example 24 20 60 Carbodiimide system 30 Example 25 20 60 Epoxy system 10 Example 26 20 60 Epoxy system 20 Example 27 20 60 Epoxy system 30

[ Comparative Example  One]

A polyester film not subjected to primer coating processing was used as Comparative Example 1.

[Comparative Examples 2 to 17]

A primer layer was formed on one surface of a polyester base film as in the examples, and the primer layers of Comparative Examples 2 to 10 were composed of 30 wt% of water-dispersed polyurethane resin and 70 wt% of Water was used as a coating liquid and the primer layer of Comparative Examples 11 to 19 was prepared by mixing 30% by weight of an acrylic binder resin and 70% by weight of water as a second binder resin having a molecular weight of 10,000 and having a reactor of Chemical Formula 1 And a second binder resin aqueous dispersion was used as a coating liquid. In this case, one kind of the coating liquid is selected as a curing agent from the oxazoline type, carbodiimide type, and epoxy type and is combined with 10 to 30 parts by weight as in the embodiment. The others are the same as in the first embodiment.

As shown in Table 2 below, the proportions of the polymer binder resin and the curing agent were controlled and the summary names were abbreviated as described above. In all Comparative Examples, the total molecular weight was adjusted to be 10,000 g / mol or less.

division The first binder resin The second binder resin Hardener Weight portion Weight portion Kinds Weight portion Comparative Example 1 0 0 - 0 Comparative Example 2 80 0 Oxazoline system 10 Comparative Example 3 80 0 Oxazoline system 20 Comparative Example 4 80 0 Oxazoline system 30 Comparative Example 5 80 0 Carbodiimide system 10 Comparative Example 6 80 0 Carbodiimide system 20 Comparative Example 7 80 0 Carbodiimide system 30 Comparative Example 8 80 0 Epoxy system 10 Comparative Example 9 80 0 Epoxy system 20 Comparative Example 10 80 0 Epoxy system 30 Comparative Example 11 0 80 Oxazoline system 10 Comparative Example 12 0 80 Oxazoline system 20 Comparative Example 13 0 80 Oxazoline system 30 Comparative Example 14 0 80 Carbodiimide system 10 Comparative Example 15 0 80 Carbodiimide system 20 Comparative Example 16 0 80 Carbodiimide system 30 Comparative Example 17 0 80 Epoxy system 10 Comparative Example 18 0 80 Epoxy system 20 Comparative Example 19 0 80 Epoxy system 30

Using the films according to Examples 1 to 27 and Comparative Examples 1 to 19, physical properties were measured through the following experimental examples, and the results are shown in Tables 3 and 4 below.

[Experimental Example]

1. Confirm Haze / light transmittance

The coating liquid prepared in Examples and Comparative Examples was coated on a PET film having a thickness of 100 탆 and thermally cured. The haze and the transmittance were measured using a haze meter manufactured by NIPPON DENSHOKU.

2. Measurement of thickness of coating layer

The thicknesses of the coating layers of the optical polyester films prepared in Examples and Comparative Examples were measured using a pressure-sensitive meter (MITUTOYO Corporation, Model: ID-Ff125) using a micrometer, Was calculated as an average of remaining values obtained by subtracting the thickness of the transparent base film.

3. Confirm adhesion

The adhesive force between the base material and the primer layer of the film prepared in Examples and Comparative Examples was measured at normal temperature and humidity. A UV-curable resin was coated on the surface to which the primer layer was adhered using a # 20 wire bar. Then, a cut line was formed on the film coated with the primer layer by a cutter, The squares were placed. Cellulose tape (No. 405, made by NICHIBAN; width: 24 mm) was attached to the film having the cutting line, and the tape was rubbed with a velvet to strongly adhere to the film, and then the tape was peeled vertically. The area of the primer layer remaining on the coating layer was visually observed, and the adhesive force was calculated by the following equation (1).

&Quot; (1) "

The adhesion test for evaluating moisture resistance after 65 hours at 65 ° C and 95% humidity was also carried out in the same manner as described above.

4. Check coating property

In the Examples and Comparative Examples, the coating properties between the primer layer coating liquid and the substrate were measured. The primer layer was applied to the substrate using # 0 to # 6 wire bar to confirm whether the primer layer was coated on the entire surface of the substrate. It was evaluated that coatings were excellent when there were no more than 2 parts in 100 small square reference (square: 1 x 1mm) with no naked eye coating solution like naked eyes.

division Optical property Adhesion Coating property Battle Transition
(%) Haze
(%) Room temperature (%) High temperature intrusion
(%) Coating property
(O /? / X) Coating layer thickness
(탆) Example 1 93.2 0.97 70 60 Δ 0.2 Example 2 92.8 0.94 80 60 Δ 0.2 Example 3 92.9 1.02 80 70 Δ 0.2 Example 4 91.9 1.10 90 70 Δ 0.2 Example 5 92.4 1.08 85 60 O 0.2 Example 6 92.2 0.99 90 75 Δ 0.2 Example 7 92.4 0.94 70 60 Δ 0.2 Example 8 93.0 0.94 60 50 Δ 0.2 Example 9 93.1 0.94 60 50 O 0.2 Example 10 92.9 0.95 90 80 O 0.2 Example 11 92.6 0.99 95 85 Δ 0.2 Example 12 92.5 0.97 95 80 O 0.2 Example 13 92.4 0.94 100 95 O 0.2 Example 14 93.0 0.94 100 90 O 0.2 Example 15 92.4 0.94 100 90 O 0.2 Example 16 91.1 1.10 90 60 O 0.2 Example 17 92.2 1.08 90 60 O 0.2 Example 18 92.7 0.99 80 50 O 0.2 Example 19 92.4 0.94 90 80 O 0.2 Example 20 92.9 0.95 100 90 O 0.2 Example 21 92.6 0.99 100 90 O 0.2 Example 22 92.5 0.97 100 95 O 0.2 Example 23 92.9 0.95 100 100 O 0.2 Example 24 93.1 0.94 100 100 O 0.2 Example 25 92.9 0.95 95 80 O 0.2 Example 26 92.5 0.97 90 80 O 0.2 Example 27 92.4 0.94 95 80 O 0.2

As can be seen from Table 3, the optical polyester films according to Examples 1 to 27 of the present invention had a weight ratio of a first binder resin having an aqueous dispersion urethane group to a second binder resin having an acryloylic functional group And the coating strength and the adhesion force of the coatings are different according to the coating weight.

division Optical property Adhesion Coating property Battle Transition
(%) Haze
(%) Room temperature (%) High temperature intrusion
(%) Coating property
(O /? / X) Coating layer thickness
(탆) Comparative Example 1 88.4 1.72 0 0 X 0.2 Comparative Example 2 91.9 0.99 0 0 X 0.2 Comparative Example 3 92.2 0.97 0 0 Δ 0.2 Comparative Example 4 92.4 0.94 10 5 O 0.2 Comparative Example 5 92.8 0.94 0 0 Δ 0.2 Comparative Example 6 93.0 0.95 20 5 O 0.2 Comparative Example 7 93.0 1.00 20 5 O 0.2 Comparative Example 8 92.2 0.97 0 0 Δ 0.2 Comparative Example 9 92.4 0.94 0 0 O 0.2 Comparative Example 10 93.0 0.95 5 0 O 0.2 Comparative Example 11 93.0 1.00 80 15 O 0.2 Comparative Example 12 92.2 0.97 70 30 Δ 0.2 Comparative Example 13 92.4 0.94 10 5 Δ 0.2 Comparative Example 14 92.8 0.94 85 25 Δ 0.2 Comparative Example 15 93.0 0.95 75 25 Δ 0.2 Comparative Example 16 93.0 1.00 80 15 O 0.2 Comparative Example 17 92.2 0.97 50 30 Δ 0.2 Comparative Example 18 92.4 0.94 20 10 Δ 0.2 Comparative Example 19 93.0 0.95 20 10 Δ 0.2

As can be seen from Table 4, in the case of the optical polyester film according to the comparative example, when each of the binders was used, the adhesion was relatively weakened compared with the examples, and the coating property also tended to be lowered.

In comparison with the optical polyester films according to Examples 1 to 27 of the present invention and the optical polyester films according to Comparative Examples 1 to 19, there was no significant difference in optical properties, but the combination of binders, type and ratio of curing agent Therefore, there was a difference in effectiveness.

In particular, the polyester films for optical films according to Examples 23 to 24 of the present invention were obtained by applying a carbodiimide-based curing agent at a weight ratio of the first binder resin and the second binder resin of 1: 3, . In other words, unlike the other examples and comparative examples, the best results were obtained with respect to the target properties such as the room temperature bonding strength, the moisture resistance adhesion, the optical properties and the coating properties, and the coating properties and the adhesive properties were slightly changed . In case of high temperature and humidity environment, adhesion property was often decreased, and if the content of the first binder resin was too high, this also resulted in lowering of adhesion and coating property, and it was confirmed that it was necessary to optimize an appropriate amount .

It is to be understood that the present invention is not limited to the above embodiments and various changes and modifications may be made by those skilled in the art without departing from the spirit and scope of the invention.

1: Polyester base film
2: Primer layer
3: Functional coating layer (second UV post-processing)

Claims (7)

A polyester base film; and a primer layer formed on one side or both sides of the base film,
The primer layer is applied with a primer composition comprising a mixed resin composed of a first binder resin having a urethane group and an acryloyl reactor and a second binder resin having a molecular weight of 5,000 to 50,000 g / mol and at least one crosslinking agent Formed,
Wherein the first binder resin is a water-dispersed polyurethane-based resin,
Wherein the basic skeleton of the second binder resin is a polyester-based polymer or a polyurethane-based polymer. delete The method according to claim 1,
Wherein the cross-linking agent is one or at least two or more selected from the group consisting of an oxazoline-based, carbodiimide-based, epoxy-based, aziridine-based and melamine-based mixture. The method of claim 3,
Wherein the primer layer is applied with a coating liquid comprising 20 to 60 parts by weight of the first binder resin, 30 to 60 parts by weight of the second binder resin, and 1 to 35 parts by weight of the crosslinking agent. . 5. The method of claim 4,
Wherein the primer layer is applied with a coating liquid comprising 20 parts by weight of the first binder resin, 60 parts by weight of the second binder resin and 20 to 30 parts by weight of the carbodiimide crosslinking agent. . The method according to claim 1,
Wherein the primer layer has a thickness of 0.02 to 0.3 占 퐉. 7. The method according to any one of claims 1 to 6,
Wherein the adhesive force between the coating layer composed of the acrylic resin formed on the primer layer and the primer layer is 95% or more after the wettability test for 360 hours at 65 캜 and 95% humidity.

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