KR20100081136A - Optical polyester laminated film with improved brightness - Google Patents

Abstract

PURPOSE: An optical polyester laminated film is provided to improve the vertical luminance value of the film after a post-manufacturing process of a hard coating, a lens, and a prism. CONSTITUTION: An optical polyester laminated film with the improved luminance value uses a polyester film with the thickness of 50~500 micrometers as a base film, and includes a primer film formed with a polymer bonding layer on one side of the base film. The primer film uses a binder resin selected from the group consisting of a urethane resin, an acrylic resin, or a polyester copolymer resin. The primer film includes 1.0~90wt% of binder resin, 1.0~50wt% of functional hardener, 0.1~20wt% of silica nanoparticle, and 0.1~20wt% of halo silica nanoparticle in a ring shape.

Description

OPTICAL POLYESTER LAMINATED FILM WITH IMPROVED BRIGHTNESS}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical polyester laminated film having an improved luminance, and more particularly, to an optical poly-layer having an improved luminance, which increases the vertical luminance value after post-processing such as a prism, lens, or hard coating. It relates to an ester laminated film.

In general, the polyester laminated film is excellent in dimensional stability, thickness uniformity and optical transparency, it is widely used in various industrial materials as well as display devices.

In the case of the optical polyester film of the polyester laminated film, the primer layer uses an acrylic or polyester-based binder, and due to the production processability, silica or alumina particles of 80 to 200 nm are used. As light passes through the film, the light is dispersed and lost, and the light passing vertically decreases. In addition, a problem of deterioration in post-processing such as a prism, a lens, an antireflection layer, or a hard coating occurs.

Therefore, in order to improve the brightness, a situation in which a structure capable of reducing light loss by controlling the refractive index from the primer layer is required.

The present invention, in order to solve the above problems and meet the conventional requirements, to create a structure that can reduce the loss of light by giving a refractive index gradient to the primer layer to make the vertical luminance after post-processing, such as prism, lens, or hard coating The purpose of the present invention is to provide an optical polyester laminated film having an increased brightness and other optical properties.

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 an optical film having a polyester film having a thickness of 50 to 500 µm as a base film, wherein a primer layer is formed on at least one side of the base film as a polymer adhesive layer, and the primer layer is urethane, acrylic or poly An ester copolymer resin is used as the binder resin, and a functional curing agent and hollow silica nanoparticles having a ring structure having a low refractive index of 5 to 80 nm and an average particle diameter of 10 to 300 nm are included. 1.0 to 90.0% by weight of the binder resin used, 1.0 to 50.0% by weight of the functional curing agent, 0.1 to 20.0% by weight of the silica nanoparticles and 0.1 to 20.0% by weight of the hollow silica nanoparticles light having improved brightness Achieved by an academic polyester laminated film.

Here, the refractive index of the hollow silica nanoparticles is characterized in that 1.40 ~ 1.55.

In addition, the surface of the base film is characterized in that the total light transmittance is 85% or more, haze value is 0.3 ~ 2% or less.

In addition, the adhesion between the base film and the primer layer is characterized in that 100% after a 96 hours moisture resistance test at 65 ℃, 95% humidity.

In addition, the base film is a biaxially oriented polyester film, the primer layer is characterized in that it is applied to at least one side after the uniaxial stretching of the biaxially oriented polyester film.

In addition, the thickness of the primer layer is characterized in that 0.01 ~ 5.00㎛.

According to the present invention, the (vertical) luminance value is improved after a post-processing process such as a prism, lens or hard coating.

Therefore, according to the optical polyester laminated film having the improved brightness according to the present invention, since the brightness increase effect is excellent in the prism lens processing, the hard coat processing, the AR processing and the diffusion, etc. Can be used over. In particular, as an optical film, there is an effect useful as a base film for prism sheets, a base film for backlights, a hard coat process, a base film for AR films, and a protective film in a CRT.

Hereinafter, the present invention will be described in detail with reference to embodiments of the present invention. These examples are only presented by way of example only to more specifically describe the present invention, it will be apparent to those skilled in the art that the scope of the present invention is not limited by these examples. .

Optical polyester laminated film having an improved brightness according to the present invention, unlike conventional optical polyester laminated film, using the nanoparticles having two different structures and refractive index and the effect of increasing the brightness through the refractive index gradient and The present invention relates to an optical polyester laminated film having an improved luminance excellent in all other optical properties.

That is, the optical polyester laminated film having the improved brightness according to the present invention is a method for increasing the (vertical) brightness for the optical, urethane, acrylic or polyester (CoPET) copolymer resin generally used in the industry It is used as a binder resin and simultaneously puts two particles to change the structure of the upper and lower parts of the primer layer due to the difference in density, which helps to increase the transmittance of light. The present invention also relates to an optical polyester laminated film having an improved luminance that can be used throughout various optical members having excellent optical properties.

To this end, the optical polyester laminated film having an improved luminance according to the present invention has a polyester film having a thickness of 50 to 500 μm as a base film, and an optical layer having a primer layer formed as a polymer adhesive layer on at least one side of the base film. As the film for the primer, the primer layer is a urethane, acrylic or polyester copolymer resin using a binder resin, a functional curing agent and silica nanoparticles having an average particle diameter of 10 to 300 nm and a hollow silica having a low refractive index of 5 to 80 nm. Including nanoparticles, 1.0 to 90.0% by weight of the binder resin used in the primer layer, 1.0 to 50.0% by weight of the functional curing agent, 0.1 to 20.0% by weight of the silica nanoparticles and 0.1 to 20.0% by weight of the hollow silica nanoparticles Characterized in that made.

The copolyester-based resin for forming an optical polyester laminated film having an improved luminance according to the present invention preferably comprises a dicarboxylic acid component and a branched glycol component as components.

Examples of the branched glycol component include 2,2-dimethyl-1,3-propanediol, 2-methyl-2-ethyl-1,3-propanediol, 2-methyl-2-butyl-1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2-methyl-2-isopropyl-1,3-propanediol, 2-methyl-2-n-hexyl-1,3-propanediol, 2, 2-diethyl-1,3-propanediol, 2-ethyl-2-n-butyl-1,3-propanediol, 2-ethyl-2-n-hexyl-1,3-propanediol, 2,2- Di-n-butyl-1,3-propanediol, 2-n-butyl-2-propyl-1,3-propanediol, 2,2-di-n-hexyl-1,3-propanediol, and the like. have. It is preferable to contain the branched glycol component in the total glycol component in a ratio of 10 mol% or more, particularly preferably in a ratio of 20 mol% or more. Moreover, it is preferable to contain the branched glycol component in a ratio of 80 mol% or less in the total glycol component. If it is less than 10 mol%, there exists a tendency for adhesiveness with a biaxially-oriented polyester film to become inadequate. As glycol components other than the said compound, ethylene glycol is the most preferable. As small amount, diethylene glycol, propylene glycol, butanediol, hexanediol or 1,4-cyclohexanedimethanol may be used.

Moreover, as dicarboxylic acid component contained as a component in co-polyester type resin, terephthalic acid and isophthalic acid are the most preferable. If small amount, other dicarboxylic acid, especially diphenylcarboxylic acid and aromatic dicarboxylic acid of 2, 6- naphthalenedicarboxylic acid, may be added and copolymerized. In addition to the dicarboxylic acid component, in order to impart water dispersibility, it is preferable to use 5-sulfoisophthalic acid in the range of 1 to 10 mol%, for example, sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfo Naphthalene isophthalic acid-2,7-dicarboxylic acid, 5- (4-sulfophenoxy) isophthalic acid, its salts, etc. are mentioned.

The adhesive layer (primer layer) of the optical polyester laminated film having the improved luminance according to the present invention has an adhesive force with UV curable resin coated on the primer layer when processed to a dispersed urethane resin, acrylic or polyester copolymer resin. It also increases the durability due to network formation.

A surfactant is used for use in the water-soluble coating liquid of the optical polyester laminated film having the improved brightness according to the present invention, and a known anionic or nonionic surfactant is used to increase the wettability of the base film and to uniformly apply the coating liquid. It is preferable to apply | coat to a base film using a required amount.

In the present invention, in the optical polyester laminated film having improved luminance, the base film is a biaxially oriented polyester film, and the primer layer is preferably applied to at least one side after uniaxial stretching of the biaxially oriented polyester film. At this time, it is preferable that the thickness of the primer layer to which resin was apply | coated is 0.01-5.00 micrometers, More preferably, it is 0.01-3.00 micrometers. This is because if the thickness of the coating is thinner than 0.01 μm, the transparency becomes good but the adhesive strength is reduced during post-processing, and when the coating thickness is thicker than 5 μm, the adhesive property is excellent but the transparency and the coating property are not preferable.

In addition, in the optical polyester laminated film having an improved brightness according to the present invention, an additive may be used in the coating liquid to improve coating properties and functionality, and such additives may include organic particles, inorganic particles, antifoaming agents, and the like. According to the present invention, the water-soluble polymer primer layer may include inorganic particles having a relatively small difference in refractive index with the resin, thereby ensuring runability. However, when the average particle diameter of the inorganic particles exceeds 500 nm, problems may occur in the haze. do. Accordingly, the size of the silica inorganic particles used in the present invention has a particle size in the range of 10 to 300 nm, and the hollow hollow silica nanoparticles having a low refractive index in order to increase the vertical luminance through the refractive index gradient It may have a range of 5 ~ 80 nm. In addition, the refractive index of the hollow silica nanoparticles is most preferably 1.40 ~ 1.55. Because ordinary silica particles have a refractive index range of 1.55 to 1.65, the refractive index of hollow silica nanoparticles must be in the range of 1.40 to 1.55, causing refractive index gradient to occur in the primer layer, which helps to improve brightness.

In addition, the surface of the base film in the optical polyester laminated film having an improved brightness according to the invention is characterized in that the total light transmittance is 85% or more, haze value is 0.3 ~ 2% or less, the base film and the primer The adhesion between the layers is characterized by 100% after a 96 hour moisture resistance test at 65 ° C., 95% humidity.

Hereinafter, the present invention will be described in more detail with reference to various examples and comparative examples.

Example 1

In Example 1, the primer layer was an anionic interface in 73.8% by weight of water, 20.0% by weight of an acrylic resin dispersion in which 30% by weight of acrylic resin was dispersed in water, and 5% by weight of a curing agent aqueous dispersion in which 30% by weight of melamine curing agent was dispersed in water. 10 wt% of the active agent was dispersed in water 1.0 wt% of the surfactant aqueous dispersion, 70 wt% of the colloidal silica particles having an average particle diameter of 80nm, 0.1 wt% of the colloidal silica particle dispersion dispersed in the water, an average particle diameter of 20nm, the refractive index is 1.48 The coating liquid was prepared using 0.1 wt% of the hollow silica nanoparticle aqueous dispersion in which 70 wt% of the hollow silica nanoparticles having a phosphorus ring structure was dispersed in water.

The polyester substrate used in the present embodiment is a 188㎛ PET film produced by Toray Saehan Co., Ltd. and the PET film was applied after uniaxial stretching and biaxially stretching to prepare an optical polyester laminated film having improved luminance.

[Example 2]

In Example 2, the primer layer was composed of 73.8 wt% of water, 30 wt% of copolyester (CoPET) resin, and 20.0 wt% of aqueous dispersion of polyester copolymer resin dispersed in water, and 30 wt% of melamine curing agent dispersed in water. 1.0 wt% of an aqueous dispersion of surfactants dispersed in water in 10 wt% of anionic surfactants in 5 wt% of a dispersion, and 0.1 wt% of an aqueous dispersion of colloidal silica particles dispersed in water of 70 wt% of colloidal silica particles having an average particle diameter of 80 nm. And a coating liquid was prepared by using a hollow silica nanoparticle aqueous dispersion of 0.1 wt% of 70 wt% of the hollow silica nanoparticles having a ring structure having an average particle diameter of 20 nm and a refractive index of 1.48 dispersed in water.

The polyester substrate used in the present embodiment is a 188㎛ PET film produced by Toray Saehan Co., Ltd. and the PET film was applied after uniaxial stretching and biaxially stretching to prepare an optical polyester laminated film having improved luminance.

Comparative Example 1

In Comparative Example 1, the primer layer had an anionic interface at 73.9% by weight of water, 20.0% by weight of an acrylic resin dispersion in which 30% by weight of acrylic resin was dispersed in water, and 5% by weight of a curing agent aqueous dispersion in which 30% by weight of melamine curing agent was dispersed in water. A coating liquid was prepared by using 1.0% by weight of an aqueous dispersion of surfactant dispersed in water and 0.1% by weight of an aqueous dispersion of colloidal silica particles dispersed in water, in which 1.0% by weight of a surfactant dispersion dispersed in water and 70% by weight of colloidal silica particles having an average particle diameter of 80 nm were used. .

The polyester substrate used in this comparative example is a 188㎛ PET film produced by Toray Saehan Co., Ltd. and the PET film was applied after uniaxial stretching and then biaxially stretching to prepare an optical polyester laminated film.

Comparative Example 2

In Comparative Example 1, the primer layer was composed of 73.9 wt% of water and 30 wt% of copolyester (CoPET) resin dispersed in water, 20.0 wt% of aqueous dispersion of polyester copolymer resin, and 30 wt% of melamine curing agent dispersed in water. 1.0 weight% of surfactant aqueous dispersion in which 10 weight% of anionic surfactant was dispersed in water, and 70 weight% of colloidal silica particles having an average particle diameter of 5 weight% in dispersion, 0.1 weight of colloidal silica particle dispersion in water The coating liquid was prepared using%.

The polyester substrate used in this comparative example is a 188㎛ PET film produced by Toray Saehan Co., Ltd. and the PET film was applied after uniaxial stretching and then biaxially stretching to prepare an optical polyester laminated film.

Experimental Example 1

After coating and thermosetting the 188 ㎛ PET film with the coating solution prepared in Examples and Comparative Examples was measured turbidity and transmittance using a HAZE meter manufactured by NIPPON DENSHOKU.

Experimental Example 2

After applying the 188 ㎛ PET film with the coating solution prepared in Examples and Comparative Examples and thermosetting, each luminance value was measured by BM7 manufactured by TOPCON. Here, the luminance value 5000cd was set to 100% based on Comparative Example 1, and the relative luminance value was compared.

The results according to Experimental Example 1 and Experimental Example 2 are shown in Table 1 below.

TABLE 1

Item materials
thickness
(Μm) bookbinder Hardener Hollow Silica Nanoparticles Turbidity /
Transmittance Luminance Example 1 188 Acrylic binder Melamine O 0.49 / 92.1 102% Example 2 188 Polyester
(CoPET) Binder Melamine O 0.78 / 91.1 101% Comparative Example 1 188 Acrylic binder Melamine X 0.47 / 91.9 100% Comparative Example 2 188 Polyester
(CoPET) Binder Melamine X 0.78 / 90.9 99%

As can be seen in Table 1, the optical polyester laminated film having an improved luminance according to an embodiment of the present invention is a result of the structure to reduce the loss of light by giving a refractive index gradient to the primer layer prism, lens or After the post-processing such as hard coating it can be seen that the vertical luminance value is increased compared to the comparative example.

Claims (6)

In the optical polyester laminated film having an improved brightness, As an optical film which used the polyester film of 50-500 micrometers in thickness as a base film, and provided the primer layer as a polymer easily bonding layer on at least one surface of the said base film, The primer layer uses urethane, acrylic or polyester copolymer resin as a binder resin, and has a functional curing agent and hollow silica nanoparticles having a ring refractive index of 10 to 300 nm and a low refractive index of 5 to 80 nm. Including particles, 1.0 to 90.0% by weight of the binder resin used in the primer layer, 1.0 to 50.0% by weight of the functional curing agent, 0.1 to 20.0% by weight of the silica nanoparticles and 0.1 to 20.0% by weight of the hollow silica nanoparticles, characterized in that Optical polyester laminated film with improved brightness. The method of claim 1, The refractive index of the hollow silica nanoparticles is characterized in that 1.40 ~ 1.55, the polyester polyester film for improved brightness. The method of claim 1, The surface of the base film is a total light transmittance of 85% or more, haze value is characterized in that 0.3 ~ 2% or less, optical polyester laminated film having improved brightness. The method of claim 1, The adhesive force between the base film and the primer layer is 100% after a 96 hour moisture resistance test under 65 ℃, 95% humidity, optical polyester laminated film having an improved brightness. The method of claim 1, The base film is a biaxially oriented polyester film, wherein the primer layer is applied to at least one side after the uniaxial stretching of the biaxially oriented polyester film, optical polyester laminated film having improved brightness. 6. The method according to any one of claims 1 to 5, The thickness of the primer layer is characterized in that 0.01 ~ 5.00㎛, the optical polyester laminated film having an improved brightness.