KR101362877B1 - Gas barrier film - Google Patents

Abstract

The present invention includes an ultraviolet curable hard coating layer copolymerized with a monomer having a specific structure in a gas permeation barrier layer, thereby increasing the flatness of the base film, preventing cracking and deformation, and improving thermal stability, processability, gas permeability, surface hardness and It is to provide a gas barrier film that provides barrier properties with an inorganic layer.

Description

Gas barrier film {

The present invention relates to a gas barrier film. More specifically, the present invention includes an ultraviolet curable organic and inorganic hybrid hard coating layer copolymerized with a monomer having a specific structure as a buffer layer of a gas barrier film, thereby increasing flatness of the plastic base film, preventing cracking and deformation, and improving It is to provide a gas barrier film that provides thermal stability, processability, gas permeability, surface hardness and barrier properties with the inorganic layer.

With the continuous development of information and communication technology, it is expected to evolve from the current flat glass display era to the flexible display era. Although plate glass is used a lot as a display substrate, glass is not easy to be broken and has no bendability, has a high specific gravity and is difficult to be processed into various forms.

Plastic substrates, on the other hand, are thinner, lighter, more flexible and can be processed into a variety of shapes than glass. However, plastic substrates developed to date show inferior physical properties to glass in terms of heat resistance, moisture and / or oxygen barrier properties, and processability.

Plastic substrates used in flexible displays generally include three layers in order to have physical properties required for substrate processing and use. The flexible display plastic substrate may be formed of a plastic substrate film that is the basis of the substrate, a gas barrier layer made of an inorganic layer to provide oxygen and moisture barrier properties, and cracks on the plastic substrate due to a difference in physical properties between the base film and the gas barrier layer. It consists of the flat layer which is a buffer layer for preventing and improving the flatness of a base film.

In manufacturing flexible display plastic substrates, the difference in physical properties, especially the coefficient of thermal expansion (CTE), between the base film as the organic layer and the gas barrier film as the inorganic layer is large, resulting in a decrease in coating stress and adhesion caused during the process. There is a problem that cracks occur or the coating layer is peeled off. The thermal expansion rate of the plastic base film used as the substrate is 10-100ppm / ℃, whereas the thermal expansion of the gas barrier film is very small, 5 ~ 9 ppm / ℃, the difference in thermal expansion between the base film and the gas barrier film when exposed to the substrate process conditions Due to this problem, cracks may be formed or peeled off, and the problem becomes more severe as the structure of the gas barrier layer, which is an inorganic layer, is increased in order to increase gas barrier properties. In addition, the base film having poor flatness may cause problems due to a decrease in the barrier property and a flatness during the substrate process due to the flatness of the inorganic layer.

An object of the present invention is to increase the flatness of the base film to provide a gas barrier film without the occurrence of initial warpage, cracks.

Another object of the present invention is to provide a gas barrier film which prevents cracking and deformation and provides improved thermal stability, fairness, gas permeability, surface hardness and barrier property with the inorganic layer.

Gas barrier film of the present invention comprises a base film, at least one UV-curable oil, inorganic hybrid hard coating layer and at least one inorganic layer, the UV-curable hybrid hard coating layer is a polyfunctional phosphazene monomer and surface of the formula It may include modified silica.

[Formula 1]

In one embodiment, the multifunctional phosphazene monomer of Formula 1 may be included in 10-80% by weight based on solids in the UV-curable hybrid hard coating layer.

In one embodiment, the surface-modified silica may be included in 10-55% by weight based on solids in the UV-curable hybrid hard coating layer.

In one embodiment, the UV curable hybrid hard coating layer may further include at least one selected from the group consisting of a polyfunctional acrylate monomer and a polyfunctional acrylate oligomer and a photoinitiator.

In one embodiment, the gas barrier film may have a structure in which the ultraviolet curable hard coating layer and the inorganic layer are laminated on one or both surfaces of the base film.

In one embodiment, the base film may be a high heat resistant plastic film.

In one embodiment, the base film may further contain inorganic particles.

In one embodiment, the coefficient of thermal expansion (CTE) of the ultraviolet curable hybrid hard coating layer may be 30-50 ppm / ° C.

The present invention provides a gas barrier film having no initial warpage and no crack generation by increasing the flatness of the base film. In addition, the present invention provides a gas barrier film that prevents cracking and deformation and provides improved thermal stability, processability, gas permeability, surface hardness, and barrier properties with the inorganic layer.

Gas barrier film of the present invention comprises a base film, at least one UV-curable hard coating layer and at least one inorganic layer, the UV-curable hard coating layer comprises a polyfunctional phosphazene monomer of the formula (1) and surface modified silica can do.

[Formula 1]

Wherein R is represented by the following formula (2),

(2)

R ₁ in Formula 2 is hydrogen; Linear or branched alkyl groups having 1 to 10 carbon atoms; Or an aryl group, an arylalkyl group, or an alkylaryl group having 6 to 30 carbon atoms, and n is an integer of 1-5).

The polyfunctional phosphazene monomer of Formula 1 is 2,2,4,4,6,6-hexahydro-2,2,4,4,6,6-hexakis (2-((2-methyl-1 -Oxo-2-propenyl) oxy) ethoxy) -1,3,5,2,4,6-triazatriphosphorin, but is not limited to these.

The polyfunctional phosphazene monomer of Formula 1 may be synthesized by a conventional synthesis method, or may be used by purchasing a commercially available product. For example, 2,2,4,4,6,6-hexahydro-2,2,4,4,6,6-hexakis (2-((2-methyl-1-oxo-2-propenyl ) Oxy) ethoxy) -1,3,5,2,4,6-triazatriphosphorine Idemitsu PPZ (Kyoeisha Chemical co., Ltd), Idemitsu PPZ U1000, 2000, 3000, 4000 (Kyoeisha Chemical co., Ltd) can be used.

The multifunctional phosphazene-based monomer of Formula 1 may be included in 10-80% by weight based on solids in the UV-curable hard coating layer. Within this range, the hardness and heat resistance of the hard coat layer are not weakened and cracks do not occur. Preferably it may be included in 20-50% by weight.

The surface modified silica can be a surface modified silica with a silane coupling agent R 1 Si (OR 2) 3. R1 may be selected from the group consisting of a (meth) acrylate group, a vinyl group and an amino group, and R2 is a linear or branched alkyl group having 1 to 3 carbon atoms as a hydrolyzable group.

The surface modified silica may have a structure of Formula 3, but is not limited thereto.

(3)

Wherein R 1 may be selected from the group consisting of a (meth) acrylate group, a vinyl group and an amino group)

The surface modified silica can be synthesized by conventional synthetic methods. For example, silica surface-modified with the silane coupling agent R 1 Si (OR 2) 3 may be synthesized by the following Scheme 1.

[Reaction Scheme 1]

Wherein M + is H + or a monovalent cation of an alkali metal,

R1 may be selected from the group consisting of a (meth) acrylate group, a vinyl group and an amino group,

R2 is a linear or branched alkyl group of 1-3 carbon atoms)

In Scheme 1, the silane coupling agent R 1 Si (OR 2) 3 may form surface-modified silica by condensation and hydrolysis reaction with silica.

The surface modified silica can be prepared by polymerizing 80-99% by weight of silica and 1-20% by weight of silane coupling agent R1Si (OR2) 3.

Alternatively, the surface-modified silica can be used by purchasing a commercially available product. For example, Nanopol C764 (nano resins co., Ltd) can be used.

The surface-modified silica may be included in 10-55% by weight based on solids in the UV-curable hybrid hard coating layer. Within this range, the hardness and heat resistance of the hard coat layer are not weakened and cracks do not occur. Preferably it may be included in 25-40% by weight.

The UV curable hybrid hard coating layer may further include at least one selected from the group consisting of a polyfunctional acrylate monomer and a polyfunctional acrylate oligomer and a photoinitiator in addition to the multifunctional phosphazene monomer and the surface-modified silica of Formula 1. .

At least one member selected from the group consisting of a polyfunctional acrylate monomer and a polyfunctional acrylate oligomer may be included in an amount of 9-25% by weight, preferably 10-25% by weight, based on the solid content of the UV-curable hard coating layer. Within this range, shrinkage reduction and heat resistance can be improved.

The polyfunctional acrylate monomers include dipentaerythritol hexaacrylate, pentaerythritol triacrylate, tri (2-hydroxyethyl) isocyanuate triacrylate, trimethylpropane triacrylate, hexanediol diacrylate and dicy It may be one or more selected from the group consisting of clodecane dimethanol diacrylate, but is not limited thereto.

The polyfunctional acrylate monomer may be included in the 9-25% by weight based on solids in the UV curable hard coating layer. Within this range, the hardness and heat resistance of the hard coat layer are not weakened and cracks do not occur. Preferably it may be included in 10-25% by weight.

The multifunctional acrylate oligomer may be at least one selected from the group consisting of urethane acrylate, polyester acrylate, epoxy acrylate, silicone acrylate, acrylic acrylate and melamine acrylate oligomer, but is not limited thereto. no.

The polyfunctional acrylate oligomer may be included in an amount of 9-25% by weight based on solids in the UV-curable hard coating layer. Within this range, the hardness and heat resistance of the hard coat layer are not weakened and cracks do not occur. Preferably it may be included in 10-25% by weight.

The photoinitiator acts as an initiator for photocuring upon photocuring using ultraviolet light after liquid coating the composition for forming a UV curable hard coating layer on the surface of the base film.

Photoinitiators can be used any photoinitiator that generally acts on ultraviolet light. For example, 1-hydroxycyclohexyl-phenyl ketone of alpha hydroxyketone series may be used, but is not limited thereto.

The photoinitiator may be included in an amount of 1-10% by weight based on solids in the UV-curable hard coating layer. Within this range, the hardness and heat resistance of the hard coat layer are not weakened and cracks do not occur. Preferably it may be included in 2-6% by weight.

UV-curable hard coating layer is at least one selected from the group consisting of a multifunctional phosphazene monomer, a polyfunctional acrylate oligomer and a polyfunctional acrylate monomer of the formula (1), further comprises an additive for providing additional functions in addition to the photoinitiator can do. For example, the additives include, but are not limited to, leveling agents, antistatic agents, antifoaming agents, light blocking agents, ultraviolet absorbers, plasticizers, lubricants, fillers, colorants, stabilizers, lubricants, crosslinkers, antiblocking agents, antioxidants, and the like. It is not. The additive may be included in an amount of 0.01-1 part by weight based on 100 parts by weight of the hard coat layer, but is not limited thereto.

The ultraviolet curable hard coat layer may have a thickness of 0.1-10 μm, preferably 3-6 μm. Within this range, it is possible to increase the flatness of the base film so that no initial warpage occurs and no crack occurs.

The UV curable hard coat layer may have a thermal expansion coefficient (CTE) of 30-50 ppm / ° C. This minimizes the difference between 5-9 ppm / ° C., which is the thermal expansion rate of the inorganic layer, and 10-100 ppm / ° C., which is the thermal expansion rate of the base film. .

In the gas barrier film, the base film may be a high heat-resistant plastic film having high light transmittance, excellent heat resistance capable of withstanding the display process temperature, and low thermal expansion rate. For example, the base film may be a single polymer or a mixture of one or more polymers. Specifically, the base film may be at least one selected from the group consisting of polyether sulfone, polycarbonate, polyimide, polyetherimide, polyacrylate, polyethylene naphthalate, and polyester film, but is not limited thereto. no.

The thickness of the base film may be 20-150㎛, preferably 70-100㎛. Within this range, mechanical strength, flexibility, transparency, heat resistance, and the like may be excellent as the base film of the gas barrier film.

The base film may further include inorganic particles. The inorganic particles may be at least one selected from the group consisting of, for example, silica, plate or spherical glass flakes and nanoclays. The inorganic particles may be included in 20-65% by weight based on solids in the base film.

Thermal expansion coefficient (CTE) of the base film may be 20-100 ppm / ℃.

As the inorganic material constituting the inorganic layer in the gas barrier film, silicon, aluminum, magnesium, zinc, tin, nickel, titanium, hydrocarbons, tantalum or the like or oxides, carbides, nitrides or mixtures thereof may be used. Preferably, silicon oxide, aluminum oxide, tantalum oxide, titanium oxide can be used.

Although the method of forming an inorganic layer can use all methods, such as a vapor deposition method and a coating method, a vapor deposition method is preferable at the point that a uniform thin film with high gas barrier property is obtained. Such vapor deposition methods include methods such as physical vapor deposition (PVD) and chemical vapor deposition (CVD), such as vacuum deposition, ion plating, and sputtering.

The thickness of the inorganic layer may generally be 20-100 nm, preferably 60-90 nm. Within this range, sufficient gas barrier property is obtained, and transparency is also excellent without causing cracking or peeling in the inorganic layer.

The coefficient of thermal expansion (CTE) of the inorganic layer may be 2-9 ppm / ° C.

The gas barrier film of the present invention has a structure in which the UV curable hard coating layer and the inorganic layer are laminated on one or both surfaces of the base film, and the laminated structure may be repeated one or more times, preferably two or more times. have.

Looking at the specific laminated structure of the gas barrier film as follows, but is not limited to these.

(1) Substrate Film-UV Curing Hard Coating Layer-Inorganic Layer

(2) Base Film-Inorganic Layer-UV Curing Hard Coating Layer

(3) Substrate film-UV curable hard coating layer-Inorganic layer-UV curable hard coating layer-Inorganic layer

(4) Substrate Film-Inorganic Layer-UV Curing Hard Coating Layer-Inorganic Layer-UV Curing Hard Coating Layer

(5) Inorganic Layer-UV Curing Hard Coating Layer-Base Film-UV Curing Hard Coating Layer-Inorganic Layer

(6) inorganic layer-UV curable hard coating layer-inorganic layer-UV curable hard coating layer-base film-UV curable hard coating layer-inorganic layer-UV curable hard coating layer-inorganic layer

The gas barrier film of the present invention can be produced by a conventional method for producing a gas barrier film. For example, the composition for forming a UV curable hard coating layer is coated on a base film. The composition for forming a UV curable hard coat layer may include a solvent for dissolution in addition to the solid component. As the solvent, one or more selected from the group consisting of 2-methoxyethanol, isopropanol, butyl acetate, normal propanol and ethyl acetate can be used, but is not limited thereto. The composition for forming a UV curable hard coat layer is coated on a base film and UV cured at a light amount of 300-800 mJ / cm ² to form an ultraviolet curable hard coat layer on the base film. Then, the inorganic material capable of forming the inorganic layer is formed by forming an inorganic layer on the ultraviolet curable hard coating layer using physical vapor deposition (PVD), chemical vapor deposition (CVD), etc., such as vacuum deposition, ion plating, and sputtering. Gas barrier films can be prepared.

Hereinafter, the configuration and operation of the present invention through the preferred embodiment of the present invention will be described in more detail. It is to be understood, however, that the same is by way of illustration and example only and is not to be construed in a limiting sense.

Details that are not described herein will be omitted since those skilled in the art can sufficiently infer technically.

Specific specifications of the components used in the following examples and comparative examples are as follows.

1.Multifunctional acrylate monomer: dipentaerythritol hexaacrylate (DPHA) NOPCOMER 4612 (Sanopco co., Ltd), pentaerythritol triacrylate (PETA) M340 (miwon Corporation), dicyclodecane dimethanol diacryl Shin-Nakamura Chemical co., Ltd (DCPA) NK ESTER ADCP

2.Multifunctional phosphazene monomer: 2,2,4,4,6,6-hexahydro-2,2,4,4,6,6-hexakis (2-((2-methyl-1-oxo 2-propenyl) oxy) ethoxy) -1,3,5,2,4,6-triazatriphosphorine Idemitsu PPZ (Kyoeisha Chemical co., Ltd)

3.Surface Modified Silica with Silane Coupling Agent: Nanopol C764 (nano resins co., Ltd)

4.Multifunctional acrylate oligomer: polyfunctional urethane acrylate EB1290 (SK cytec co., Ltd)

5.Photoinitiator: 1-hydroxy-cyclohexyl-phenyl-ketone Irgacure 184 (Ciba specialty Chemical Inc)

6.Solvent: 2-methoxyethanol (MCS), butyl acetate (BA), isopropyl alcohol (IPA)

Manufacturing example  1-7: UV curable Of hard coating layer  Produce

2.5 parts by weight of the photoinitiator Irgacure-184 was mixed with 20 parts by weight of the solvent 2-methoxyethanol and stirred at 800 rpm for 30 minutes at 25 ° C to dissolve the photoinitiator. To the obtained mixture, polyfunctional acrylate oligomer, polyfunctional acrylate monomer, polyfunctional phosphazene monomer, butyl acetate and isopropyl alcohol are added to the contents shown in Table 1 below, and stirred at 25 ° C. for 40 minutes to form an ultraviolet curable coating layer. Was prepared.

Ingredient (Unit: wt%) Production Example 1 Production Example 2 Production Example 3 Production Example 4 Production Example 5 Production Example 6 Production Example 7 Polyfunctional acrylate monomer DPHA 3 3 8 3 - 20 10 DCPA 2 2 2 - - 3 3 PETA - - - - 8 - - Multifunctional phosphazene monomer Idemitsu PPZ 9 12 18 12 20 - - Multifunctional acrylate oligomer EB1290 6 3 - 6 10 10 20 Surface modification
Silica Nanopol c764 13 10 12 12 10 - - Photoinitiator Irgacure 184 2.5 2.5 2.5 2.5 2.5 2.5 2.5 menstruum MCS 20 20 20 20 20 20 20 BA 17.5 20.5 10.5 27.5 9.5 17.5 17.5 IPA 27 27 27 27 20 27 27

Example  1: gas Barrier  Production of film

The UV curable coating layer composition prepared in Preparation Example 1 was poured onto the polyethylene terephthalate base film, and then applied by scratching at 30 m / min with a # 9 coat bar. After uniformly applying, dried in an oven at 60 ℃ for 5 minutes and UV-cured at a light amount of mercury lamp 800mJ / cm ² to prepare an ultraviolet curable hard coating layer. It was placed in a chamber of a batch sputtering apparatus on the hard coating layer and silicon nitride was installed in the chamber as a target. The distance between the silicon nitride and the hard coat layer was set to 50 mm. Oxygen and argon were used as additive gases at the time of film formation. The chamber was depressurized to a vacuum degree of 2.5 x 10 ^-4 Pa, the oxygen gas was introduced into the chamber at a flow rate of 10 sccm (standard cubic centimeter per minute), argon gas at a flow rate of 30 sccm, and a hard coating layer with an input power of 1.2 KW by RF magnetron sputtering. An inorganic barrier layer which is a silicon nitride film having a thickness of 100 nm was formed on the phase.

Example  2-5: gas Barrier  Production of film

A gas barrier film was prepared in the same manner as in Example 1, except that the UV curable coating layer composition prepared in Preparation Example 1 was used in Table 2 below.

Comparative Example 1-2: Preparation of Gas Barrier Film

A gas barrier film was prepared in the same manner as in Example 1, except that the UV curable coating layer composition prepared in Preparation Example 1 was used in Table 2 below.

Experimental Example: Measurement of Physical Properties of Gas Barrier Film

The physical properties described in Table 2 below were measured for the gas barrier films prepared in Examples and Comparative Examples, and the results are shown in Table 2 below.

≪ Method for measuring physical properties &

1.Initial Warping: After placing the gas barrier film 100 mm x 100 mm in a flat position, the highest bending height was measured. H is shown in the following figure. When the measured H is less than 5 mm, it is described as "good", and when it is 5 mm or more, it is described as "bad."

2. High heat resistance: The gas barrier film 100mm x 100mm was left in the Convection oven (product name, manufacturer) for 3 hours at 150 ℃ and visually observed the appearance was measured whether cracks were generated.

3. Scratch resistance: With the steelwool # 0000 on the gas barrier film 100mm x 100mm, abrasion was performed 10 times at 50g load to determine whether there was a scratch.

Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 UV Curing Hard Coating Layer Production Example 1 Production Example 2 Production Example 3 Production Example 4 Production Example 5 Production Example 6 Production Example 7 Initial bending Good Good Good Good Good Bad Bad High heat resistance No crack No crack No crack No crack No crack With crack With crack Scratch resistance No scratch No scratch No scratch No scratch No scratch No scratch No scratch

As shown in Table 2, it can be seen that the gas barrier film of the present invention has no initial warpage phenomenon and no crack phenomenon. On the other hand, the gas barrier films of Comparative Examples 1 and 2, which do not contain the polyfunctional phosphazene-based monomer of Formula 1, were poor in the initial warpage evaluation, and cracks were generated even in the stacking of the base film-inorganic layer.

Claims (13)

A base film, at least one UV-curable hard coating layer and at least one inorganic layer, wherein the UV-curable hard coating layer is a gas barrier film comprising a polyfunctional phosphazene monomer and a surface-modified silica of the formula (1).
[Chemical Formula 1]

Wherein R is represented by the following formula (2),
(2)

R ₁ in Formula 2 is hydrogen; Linear or branched alkyl groups having 1 to 10 carbon atoms; Or an aryl group, an arylalkyl group, or an alkylaryl group having 6 to 30 carbon atoms, and n is an integer of 1-5).
The gas barrier film of claim 1, wherein the polyfunctional phosphazene monomer of Formula 1 is included in an amount of 10 to 80 wt% based on solids in the ultraviolet curable hard coating layer.
The gas barrier film of claim 1, wherein the surface-modified silica is polymerized with 80-99 wt% silica and 1-20 wt% R 1 Si (OR 2) 3. (R1 may be selected from the group consisting of a (meth) acrylate group, a vinyl group and an amino group, and R2 is a linear or branched alkyl group having 1-3 carbon atoms as a hydrolyzable group.)
According to claim 1, wherein the polyfunctional phosphazene monomer of formula 1 is 2,2,4,4,6,6-hexahydro-2,2,4,4,6,6-hexakis (2- ( (2-methyl-1-oxo-2-propenyl) oxy) ethoxy) -1,3,5,2,4,6-triazatriphosphorine.
The gas barrier film of claim 1, wherein the ultraviolet curable hard coat layer further comprises at least one selected from the group consisting of a polyfunctional acrylate monomer and a polyfunctional acrylate oligomer and a photoinitiator.
The method of claim 5, wherein the polyfunctional acrylate monomer is dipentaerythritol hexaacrylate, pentaerythritol triacrylate, tri (2-hydroxyethyl) isocyanuate triacrylate, trimethyl propane triacrylate, Gas barrier film, characterized in that at least one selected from the group consisting of hexanediol diacrylate and dicyclodecane dimethanol diacrylate.
The method of claim 5, wherein the multifunctional acrylate oligomer is at least one member selected from the group consisting of urethane acrylate, polyester acrylate, epoxy acrylate, silicone acrylate, acrylic acrylate and melamine acrylate oligomer. Gas barrier film.
The gas barrier film of claim 1, wherein the gas barrier film has a structure in which the ultraviolet curable hard coating layer and the inorganic layer are stacked on one or both surfaces of the base film.
The gas barrier film of claim 8, wherein the laminated structure of the gas barrier film is repeated one or more times.
The gas barrier of claim 1, wherein the base film is at least one selected from the group consisting of polyether sulfone, polycarbonate, polyimide, polyetherimide, polyacrylate, polyethylene naphthalate, and polyester film. film.
The gas barrier film of claim 1, wherein the base film further contains inorganic particles.
The gas barrier film of claim 11, wherein the inorganic particles are at least one selected from the group consisting of silica, plate or sphere glass flakes, and nanoclays.
The gas barrier film of claim 1, wherein a coefficient of thermal expansion (CTE) of the ultraviolet curable hard coating layer is 30-100 ppm / ° C. 7.