KR20160150335A - Anti-reflection film with excellent adhesive power - Google Patents

Abstract

The present invention relates to an antireflection film having excellent adhesion, and more particularly to an antireflection film having excellent adhesion by forming a hard coating layer containing a leveling agent on a heat-treated film.

Description

(ANTI-REFLECTION FILM WITH EXCELLENT ADHESIVE POWER)

The present invention relates to an antireflection film having excellent adhesion, and more particularly to an antireflection film having excellent adhesion by forming a hard coating layer containing a leveling agent on a heat-treated film.

Recently, image display devices (FPD) such as liquid crystal display (LCD), plasma display (PDP), cathode ray tube (CRT) and electroluminescence display (EL) -Display), a notebook, a monitor, a TV, a PC, a digital camera, and a PDA. Among them, LCD is required to have wide viewing angle, high resolution, fast response, excellent color reproducibility, and focuses on technology development to meet this demand.

In such a display, the image of the screen viewed by the eye must solve the problem of deterioration of contrast and visibility due to external light (incident light) reflected on the surface of the display or by the phenomenon of phase inversion.

An anti-glare (AG) film is disposed on the front surface of the display for reducing irregularities and reducing visibility of reflected light by scattering incident light by forming irregularities on the surface irregularities to improve visibility Anti-reflection (AR) films are also used, which alternately coat and laminate low refractive materials and high refractive materials to lower the reflectance of incident light through destructive interference during interfacial reflection.

For example, the antiglare film is formed by coating a resin containing a filler such as silica (silicon dioxide) particles having a size of several micrometers on the surface of a transparent substrate. Such an antiglare film is a type in which a concavo-convex structure is formed on the surface by aggregation of particles such as cohesive silica using sandblast, amboshing roll, chemical etching or the like, a type in which a hard coating agent for forming an anti- Or a filler having a concavity and convexity is laminated on the surface of the layer to transfer the concavo-convex shape. Among these techniques, currently preferred is a type in which a light-scattering coating composition is prepared with a resin in which inorganic or organic particles are dispersed in a hard coating agent.

The antireflective coating composition composed of the thermosetting or thermoplastic resin in which the organic and inorganic particles are dispersed is applied to a transparent substrate, followed by drying and curing. The surface irregularities vary depending on the size and content of the particles used. When an antiglare film containing such organic and inorganic particles is used, particles having a large average particle diameter cause a problem of flashing, which is a phenomenon in which a display pixel coming out from a light source inside the display is distorted by a lens functioning as a large surface irregularity. On the other hand, in the case of using particles having a small average particle size, it is possible to prevent flickering on the screen, but the film surface is whitened and the optical characteristics such as resolution, contrast and transparency are deteriorated. In order to stabilize the dispersion of particles, a milling process is performed using a separate milling machine. However, the problem of agglomeration and sedimentation of particles having a size of several to several tens of micrometers in a coating composition makes it difficult to disperse uniform particles in the composition, It is becoming the main cause of various defects.

In order to consider the curl, hardness, and adhesion, UV-resin was prepared and used for the functional optical coating film. The physical properties of conventional hard coating products were 0B to 2B adhesion on air surface coating for Curl control. Therefore, studies have been made on cured hard coating films in consideration of the refractive index of Resin, the size of silica particles and the particle size distribution in order to secure low Curl and adhesion, and to control haze and visibility.

However, in the case of forming such a functional optical coating film, the surface reflection light of the coating layer; And interfacial reflection light between the base film and the coating layer, irregular interference fringes are generated. For example, when a generally used transparent hard coating film is applied to a touch panel or the like, interference patterns often occur due to non-uniformity of the transparent hard coating film.

In order to eliminate such interference fringes, an additional laminated structure may be formed between the transparent polymer film and the transparent hard coating layer constituting the transparent hard coating film. However, there is a problem that the overall thickness of the film is increased.

However, when the thickness of the coating film is small, the coating film is easily scratched and the appearance becomes dirty. When the thickness of the coating film is increased to increase the hardness, haze is increased. In addition, there is a problem that the yield is reduced due to a deficiency of a cookie.

An object of the present invention is to provide an antireflection film having excellent adhesion by forming a hard coating layer containing a leveling agent on a heat-treated film.

In order to achieve the above object, the present invention provides a triacetylcellulose film as a substrate layer; And a hard coating layer on at least one side of the triacetylcellulose film, wherein the hard coating composition of the hard coating layer comprises a hexafunctional oligomer, a lower functional oligomer, a functional monomer, a curable resin, a photoinitiator, an inorganic particle, a leveling agent and an organic solvent And an antireflection film.

At this time, the triacetylcellulose film is characterized in that it is heat-treated.

In addition, the above-mentioned hexafunctional oligomer is preferably one selected from urethane (meth) acrylate oligomer and polyester acrylate oligomer, and said functional monomer is at least two kinds selected from isocyanate-based, acrylic and acrylate-based monomers desirable.

It is also preferred that the leveling agent is dimethylpolysiloxane and is 1 to 4% by weight based on 100% by weight of the total hard coat composition.

Further, it is preferable that the hard coating composition further comprises a low-functional oligomer.

In addition, the antireflection film has a curl of 10 mm or less, a hardness of 2H 4/5, and a haze of 23 to 25%.

The antireflection film according to the present invention is not only improved in puncture defects, but also has excellent adhesion, so that it can be produced in a range of 3,600 ~ 3,800 m with minimum adherence without hunting.

Hereinafter, the present invention will be described.

The antireflection film of the present invention comprises a triacetylcellulose film as a substrate layer; And a hard coating layer on at least one side of the triacetylcellulose film.

Here, the hard coating composition of the hard coating layer is composed of a hexafunctional oligomer, a low functional oligomer, a functional monomer, a curable resin, a photoinitiator, an inorganic particle, a leveling agent, and an organic solvent.

Hereinafter, the present invention will be described in more detail with respect to each configuration.

materials

The base material of the present invention may be, for example, a cycloolefin-based derivative having a unit of a monomer including a cycloolefin such as norbornene or a polycyclic norbornene monomer, diacetylcellulose, triacetylcellulose, acetylcellulose butyrate, Cellulose acetate, vinyl acetate copolymer, polyester, polystyrene, polyamide, polyetherimide, polyacryl, polyimide, polyethersulfone, polyether sulfone, polyether sulfone, polyether sulfone, Polyvinyl alcohol, polyvinyl acetal, polyether ketone, polyether ether ketone, polyethersulfone, polymethylmethacrylate, polyethylene terephthalate, polyethylene terephthalate, polyethylene terephthalate , Polybutylene Terephthalate, polyethylene naphthalate, polycarbonate, polyurethane, and epoxy. An unoriented uniaxial or biaxial oriented film can be used.

Of these, preferred are monoaxially or biaxially oriented polyester films which are excellent in transparency and heat resistance, cycloolefin-based derivative films which are excellent in transparency and heat resistance and capable of coping with the enlargement of the film, transparency and optical anisotropy, Acetylcellulose films may be suitably used, but triacetylcellulose films are preferred.

At this time, in order to improve the crack defects of the film, it is preferable to use the film by heat treatment. The heat treatment is preferably performed at a speed of 80 m / min, but is not limited thereto.

The hard coat composition of the hard coat layer

(a) a hexafunctional oligomer and a functional monomer; And

(b) a curable resin, a photoinitiator, an inorganic particle, a leveling agent, and an organic solvent.

Examples of the hexafunctional oligomers include urethane (meth) acrylate oligomers and polyester acrylate oligomers. More specific examples include (meth) acryloyl groups, vinyl groups , Functional group having an ethylenic double bond such as allyl group, and the like are used, but the present invention is not limited thereto.

For example, the hexafunctional urethane acrylate oligomer may have a C = C bond in each of the six acrylate groups (-O-CO-H = CH ₂ ) . ≪ / RTI >

When the number of functional groups of the urethane (meth) acrylate oligomer is large, the surface resistance of the obtained surface protective layer is inferior and the weather resistance tends to decrease. Also, the surface tends to cause a wave on the surface, I see this. On the other hand, when the number of functional groups is small, the cross-linking density is lowered and the resistance to scratches is insufficient. That is, the higher the number of functional groups, the more excellent the resistance to scratches, that is, the hard coat property, and the hard coat property requires moderate softness.

Examples of the hexafunctional urethane acrylate oligomer include Miramer M600, PU510, PU20, PU640, HS Chemtron UA-8560TL, UA-800, AGA 230A2, 670A2, 675 and Ebecryl 1290 from Cytec E, But is not limited thereto.

Further, the hexafunctional polyester acrylate oligomer was obtained from Miramer PS610 of Miura KK, 706 and 707 of AGI, Ebecryl 830 and Ebecryl 837 of Cytec, PN-5600 of Polynetron, UVT-600si of HS Chemtron And the like may be used, but the present invention is not limited thereto.

On the other hand, the hard coating composition of the present invention may further include a lower functional oligomer.

When the low-functional oligomer is included, the composition has a low viscosity, a good wettability, and may be advantageous in terms of curl in curing. In addition, since the low-functionality oligomer has a small number of reactors, it generally has a small shrinkage after curing.

On the other hand, it is preferable to use at least two kinds of functional monomers as the hard coating composition of the present invention, for example, isocyanate type, acrylic type, acrylate type and the like. More specific examples thereof include acrylate type monomer Benzyl acrylate (BZA), benzyl methacrylate (BZMA), phenoxy ethyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, 3-phenoxy propyl acrylate, phenylthioethyl acrylate, cumyl phenoxy ethyl acrylate, o-phenyl phenoxy ethyl acrylate, 2- 2-hydroxy-3-phenoxy propyl acrylate, 1-hydroxy-3-phenoxy propyl acrylate, 2-hydroxy- 6-nucleic acid But are not limited to, 1,6-hexanediolpropane dimethylacrylate, phenoxyethyl acrylate (PHEA), 2-ethoxyethyl acrylate, isobornyl acrylate, It is also possible to use a polymeric material such as pentaerythritol triacrylate (PETA), dipentaerythritol pentaacrylate (DPPA), dipentaerythritol hexacrylate (DPHA), trimethylolpropane triacrylate TMPTA), methyl acrylate, ethyl acrylate, butyl acrylate, and 2-hydroxyethyl acrylate (HEA).

On the other hand, specific examples of the curable resin include, but are not limited to, an ionizing radiation curable resin, an ionizing radiation curable resin, a thermosetting resin, or the like, which is a resin that is cured by ultraviolet rays or electron beams.

Specific examples of the ionizing radiation curable resin include an acrylate-based compound having an acrylate-based functional group such as a polyester resin, a polyether resin, an acrylic resin, an epoxy resin, a urethane resin, an alkyd resin, a spiroacetal resin, Oligomers or prepolymers of polyfunctional compounds such as polybutadiene resins, polythiol polyene resins and polyhydric alcohols such as (meth) acrylates, and reactive diluents, but are not limited thereto.

Specific examples of the ionizing radiation curable resin include monofunctional monomers and polyfunctional monomers such as ethyl (meth) acrylate, ethylhexyl (meth) acrylate, styrene, methylstyrene and N-vinylpyrrolidone, Tri (meth) acrylate, triethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol (Meth) acrylate, isocyanuric acid-modified diacrylate, isocyanuric acid-modified triacrylate, bisphenol F-modified (meth) acrylate, Diacrylate, and the like, but are not limited thereto.

Specific examples of the thermosetting resin include phenol resin, urea resin, diallyl phthalate resin, melamine resin, guanamine resin, unsaturated polyester resin, polyurethane resin, epoxy resin, aminoalkyd resin, melamine- Polysiloxane resin, and the like, but are not limited thereto.

As the photoinitiator, it is possible to use IgA Cure, a Dauro Cure series of Ciba Specialty Chemicals, and a Syracur series of Dow Chemical. Typical examples of the photoinitiator include Iga Cure 184 of Ciba Specialty and IgA Cure 819 as a long wavelength initiator But is not limited thereto.

However, in the present invention, it is preferable to use a short wavelength initiator as a main initiator and a small amount of a long wavelength initiator as a photoinitiator.

As the inorganic particles, an inorganic filler can be used. For example, SiO2, Al-SiO, TiO2, ZrO2, Al2O3, In22O3, ZnO, SnO2, ITO and the like can be used. SiO2, which is preferably silica, is used.

On the other hand, the leveling agent is added to improve the problem of deterioration of adhesiveness which is a basic property of a hard coating together with a lack of leveling property when a hard coating composition is coated on a heat-treated film. Such a leveling agent is preferably, but not limited to, dimethylpolysiloxane. The leveling agent is preferably 1 to 4% by weight based on 100% by weight of the total hard coat composition.

Specific examples of the solvent include alcohols such as isopropyl alcohol, methanol and ethanol; Ketones such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; Esters such as methyl acetate, ethyl acetate and butyl acetate; Halogenated hydrocarbons such as chloroform, methylene chloride and tetrachloroethane; Or a mixture thereof, preferably acetate-based or ketone-based.

The hard coating layer according to the present invention is formed by applying the hard coating composition to one side or both sides of a light-transmitting substrate and then curing.

In the present invention, when a mixture of a resin and a solvent is applied on a substrate, the mixture penetrates (wet) into the light-transmitting substrate. Thereafter, the resin in the mixture is cured and dried to evaporate the solvent, and a hard coat layer is formed on the substrate.

The application of the hard coating composition can be carried out in a suitable manner such as die coater, air knife, reverse roll, spray, blade, casting, gravure and spin coating.

The present invention also provides a display device to which the above-mentioned hard coating film is applied.

For example, an image display apparatus to which the hard coating film according to the present invention is applied can be provided by incorporating the polarizing plate on which the hard coating film of the present invention is formed in an image display apparatus. It is also possible to provide an image display apparatus to which the hard coating film according to the present invention is applied by attaching the hard coating film of the present invention to a window of an image display apparatus.

The hard coating film of the present invention can be preferably used for reflective, transmissive, semi-transmissive LCD or LCDs of various driving types such as TN type, STN type, OCB type, HAN type, VA type and IPS type. In addition, the hard coating film of the present invention can be preferably used for various display devices such as a plasma display, a field emission display, an organic EL display, an inorganic EL display, and an electronic paper.

Hereinafter, the present invention will be described in more detail with reference to Examples. It is to be understood that the terms used in the embodiments of the present invention and the like are merely illustrative in order to facilitate understanding of the present invention and should not be construed as limiting the scope of the present invention.

Example 1

(1 wt%) of short-wavelength initiator Ciba Specialty Co., Ltd., 18 g (1 wt.%) Of a short-wavelength initiator, and 20 g of a mixture of a polyfunctional urethane acrylate oligomer CHTU5101 A small amount of long wavelength initiator TPO is added, and the curable resin is mixed. Then, a hard coating composition was prepared by adding a mixed solvent of isopropyl alcohol and methyl isobutyl ketone and butyl acetate, silica as inorganic particles and dimethyl polysiloxane (1 wt%) as a leveling agent.

The hard coating composition prepared above was applied to a heat-treated triacetylcellulose film substrate at a rate of 80 m / min.

Example 2

The procedure of Example 1 was repeated except that dimethylpolysiloxane was added in an amount of 2% by weight instead of 1% by weight.

Example 3

The procedure of Example 1 was repeated, except that dimethylpolysiloxane was added in an amount of 3 wt% instead of 1 wt%.

Example 4

The procedure of Example 1 was repeated except that dimethylpolysiloxane was added in an amount of 4 wt% instead of 1 wt%.

Comparative Example 1

The procedure of Example 1 was repeated except that no dimethylpolysiloxane was added as a leveling agent.

Experimental Example

The properties of the antireflection films prepared in Examples 1 to 4 and Comparative Example 1 were measured by the following methods, and the results are shown in Table 1 below.

1) Haze Transmittance: Total transmittance and haze were measured using a spectrophotometer (HM-150, manufactured by Murakami) (measurement method conformed to JIS K7136)

2) Pencil hardness: Pencil hardness was measured by applying a load of 500 g using a pencil hardness tester (533-M2, Yasuda). The pencil was used five times per pencil using Mitsubishi products from Japan. The pencil was expressed by the hardness of the pencil based on the occurrence of one or less of the marks (cigars), and in the case of two or more marks, Hardness. That is, the pencil hardness H means a hardness at which no marks are formed when a pencil with a hardness of H is scratched with a load of 500 g.

3) Curling: The coated film was cut into a square (20 cm x 20 cm) size and placed on a flat glass with the coated side facing upward. The distance between the glass plate and the four corners was measured at 25 ° C and 50% And the highest value was taken as the measured value.

Very good: 10 mm or less,

Good: 11 to 20 mm,

Defective: 21 to 30 mm,

Very bad: more than 30㎜

4) Repellency: The film was laminated (laminated) onto a black acrylic plate, and the reflected image was visually observed.

Good:

△: Flammability Usually,

X: bad repulsion

5) Adhesive force: 100 squares were formed by drawing 11 straight lines on the coated side of the film at intervals of 1 mm, and then peel test was conducted three times using a tape (CT-24, Nichii Co., Ltd.). Three 100 squares were tested and the average was recorded. The adhesion was calculated as follows.

Adhesion = n / 100

Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Haze (%) 23-25 23-25 23-25 23-25 23-25 Pencil hardness 4/5 4/5 4/5 4/5 4/5 curling Good Good Very good Very good Good Cloudiness △ △ ○ ○ △ Adhesion 100/100 100/100 100/100 100/100 75 to 90/100

As shown in Table 1, when a hard coating layer containing a leveling agent was formed on the heat-treated film (Examples 1 to 4), haze was 23 to 25%, pencil hardness was 2H 4/5 or more, Curl was 10 mm And an antireflection film having excellent adhesion can be produced.

Claims (7)

A triacetylcellulose film as a base layer; And
Wherein the triacetylcellulose film comprises a hard coating layer on at least one side thereof,
Wherein the hard coat composition of the hard coat layer comprises a hexagonal oligomer, a functional monomer, a curable resin, a photoinitiator, an inorganic particle, a leveling agent, and an organic solvent.
The method according to claim 1,
Wherein the triacetylcellulose film is heat-treated.
The method according to claim 1,
Wherein the hexafunctional oligomer is one selected from a urethane (meth) acrylate oligomer and a polyester acrylate oligomer.
The method according to claim 1,
Wherein the functional monomer is at least two kinds selected from isocyanate-based, acrylic-based, and acrylate-based monomers.
The method according to claim 1,
Wherein the leveling agent is dimethylpolysiloxane and is 1 to 4% by weight based on 100% by weight of the total hard coat composition.
The method according to claim 1,
Characterized in that the hard coating composition further comprises a low functional oligomer.
7. The method according to any one of claims 1 to 6,
Wherein the antireflection film has a curling of 10 mm or less, a hardness of 2H 4/5, and a haze of 23 to 25%.