KR20170093823A - Hard coat film - Google Patents

Abstract

It is an object of the present invention to provide a hard coating film having adhesion with a high adhesive (wettability with an adhesive) and preventing generation of interference fringes. The hard coating film of the present invention is a hard coating film in which a hard coat layer containing an ionization curing resin and a leveling agent is formed on at least one side of a base film, wherein the contact angle of water on the surface of the hard coating layer is 70 degrees or less, Is 20 degrees or less.

Description

Hard Coat Film {HARD COAT FILM}

The present invention relates to a hard coat film on which a hard coat layer containing an ionization curing resin and a leveling agent is formed on a base film.

Along with recent technological advances, a liquid crystal display (LCD), a plasma display (PDP) and a light emitting device display (ELD) have been developed in addition to the conventional cathode ray tube display (CRT) . Of these, LCDs are changing from notebook-type personal computers (notebook PCs) or monitors to televisions, along with technological innovations such as high viewing angle, high definition, high-speed responsiveness and color reproducibility.

In the LCD, a liquid crystal display in which a polarizing plate is disposed on both sides of a liquid crystal cell is usually used. In order to prevent scratches on the polarizing plate, a hard coating process is generally performed on the surface of the liquid crystal display. In the hard coating process, a method of attaching a hard coating film having high transparency and sufficient hardness to a polarizing plate is widely used.

In addition, a display device including a touch panel on the viewer side of a liquid crystal display, which joins a touch panel to a hard coating layer of a hard coating film located on the outermost surface of a liquid crystal display with an adhesive or the like, is increasing. As the hard coating film used in the display device having the touch panel, it is necessary to have adhesiveness (wettability) of the adhesive used for bonding the hard coating film and the touch panel, and therefore, It is known that the use of a hard coating film in which the water contact angle of the surface of the hard coating layer is suppressed to a low level is effective.

Japanese Patent Application Laid-Open No. 2013-155219 Japanese Patent Application Laid-Open No. 2001-272503

However, the hard coating films disclosed in Patent Documents 1 and 2 have excellent adhesiveness to an adhesive, but interference streaks tend to occur, and there is a problem that visibility is liable to be lowered.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a hard coating film which has adhesion with a high adhesive (wettability with an adhesive) and prevents the generation of interference fringes.

The present invention provides the following (1) to (5).

(1) A hard coat film comprising a base film and a hard coat layer formed on at least one side of the hard coat layer, the ion coat film having a contact angle of water of 70 degrees or less and a contact angle of hexadecane of 20 degrees ≪ / RTI > or less.

(2) The hard coating film according to (1), wherein the leveling agent is a fluorine-based compound.

(3) The hard coating film according to (1) or (2), wherein the amount of the leveling agent is 0.03 part by weight to 3.0 parts by weight based on 100 parts by weight of the ionization curing resin.

(4) The hard coat film according to any one of (1) to (3), wherein the ionization curing resin contains a polyfunctional acrylate and / or a urethane oligomer.

(5) The hard coating film according to any one of (1) to (4), wherein the base film is a cellulose-based film.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a hard coating film having adhesion with a high adhesive (wettability with an adhesive) and preventing generation of interference fringes. The hard coating film of the present invention is also excellent in scratch resistance.

The present invention provides a hard coat film comprising a base film and a hard coat layer formed on at least one side of the base film, the ion coat hardening resin containing a ionizing radiation curing resin and a leveling agent, wherein the contact angle of water on the surface of the hard coat layer is not more than 70 degrees, By weight or less.

In the present invention, the base film is not particularly limited and includes, for example, a film or sheet of polyethylene terephthalate, polyamide, polyethylene, polyimide, polypropylene, acrylic resin, polystyrene, cellulose acetate, . Among them, the cellulose-based film is excellent in various properties such as birefringence, optical properties such as transparency, refractive index and dispersion, furthermore, impact resistance, heat resistance and durability, and is more preferable as a base film.

In the present invention, the ionizing radiation (ionizing radiation) curable resin of the hard coating layer is not particularly limited as long as it is a transparent resin which is cured by irradiating with an electron beam or ultraviolet rays, and examples thereof include urethane acrylate resins, Acrylate resins, epoxy acrylate resins, and the like. Among them, preferred as the ionization curable resin is one containing an ultraviolet curable polyfunctional acrylate having two or more (meth) acryloyl groups in the molecule in order to obtain good adhesion with the transparent film base. Specific examples of the ultraviolet curable polyfunctional acrylate having two or more (meth) acryloyl groups in the molecule include neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, trimethylol propane Acrylate such as trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (Meth) acrylates of polyol polyacrylate, diacrylate of bisphenol A diglycidyl ether, diacrylate of neopentyl glycol diglycidyl ether, and di (meth) acrylate of 1,6-hexanediol diglycidyl ether. (Meth) acrylate obtained by esterifying an epoxy (meth) acrylate, a polyhydric alcohol and a polyvalent carboxylic acid and / or anhydride thereof with acrylic acid, Relate, there may be mentioned polyhydric alcohols, urethane (meth) polyhydric obtained through reaction between isocyanate and hydroxyl group-containing (meth) acrylate, polysiloxane (meth) acrylate and the like. Of these, it is preferable to use urethane acrylate which is excellent in both hardness and flexibility when a hard coat layer is formed.

The ionic radiation-curable resins of these hard coat layers may be used singly or in combination of two or more.

In the present invention, the thickness of the hard coat layer is not particularly limited, but is preferably in the range of 1.0 占 퐉 to 12.0 占 퐉, for example. If the thickness of the coating film is less than 1.0 mu m, it is difficult to obtain the required surface hardness. When the thickness of the coating film is more than 12.0 占 퐉, the curl is too strong and the handleability is lowered in the production process of the through-flow curl. Further, the thickness of the hard coat layer can be measured by measuring with a micrometer.

In the present invention, the hard coat layer may contain, in addition to the ionization curing resin and the leveling agent, a polymerization initiator, a defoaming agent, a lubricant, an ultraviolet absorber, a light stabilizer, a polymerization inhibitor, a wetting and dispersing agent, a rheology control agent, A hard coat paint obtained by dissolving and dispersing the above additives in an appropriate solvent may be applied onto a substrate film, dried, and cured .

The solvent which can be used in the present invention may be appropriately selected according to the solubility of the resin to be compounded and may be a solvent capable of uniformly dissolving or dispersing at least a solid content (resin, polymerization initiator, and other additives). Examples of the solvent include aromatic solvents such as toluene, xylene and n-heptane; aliphatic solvents such as cyclohexane, methylcyclohexane and ethylcyclohexane; aliphatic solvents such as methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, Ester solvents such as methyl acetate, butyl acetate and methyl lactate, ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, alcohol solvents such as methanol, ethanol, isopropyl alcohol and n- May be used singly or in combination of several kinds as appropriate.

The coating method of the hard coating layer of the present invention is not particularly limited, but it is possible to use a coating method such as gravure coating, microgravure coating, fountain bar coating, slide die coating, slot die coating, screen printing, And then dried at a temperature of usually about 50 to 120 ° C to remove the solvent.

As a method of coating the base film and hardening the hard coat paint from which the solvent has been removed, a method of irradiating with an electron beam or ultraviolet ray can be used. The irradiation conditions and the like may be appropriately adjusted in accordance with the electron beam hardening type resin to be used and various other chemicals to be added. Further, the curing reaction can be carried out with a reduced oxygen concentration, such as under a nitrogen gas atmosphere.

The coating thickness of the hard coating layer formed on the hard coating film can be measured by a known method such as measurement using a micrometer.

In the present invention, the leveling agent contained in the hard-coded layer may be a fluorine-based, acrylic-based or siloxane-based leveling agent. Among them, the leveling agent is preferably a type containing a hydroxyl group in order to lower the water contact angle of the surface of the hard coat layer, and in particular, it is effective to use a predetermined leveling agent of a fluoric type.

The specific fluorine leveling agent referred to herein is, for example, a fluorine leveling agent containing at least a hexafluoropropene oligomer derivative. The fluorine leveling agent containing such a hexafluoropropene oligomer derivative is a compound having a molecular structure of a perfluoroalkenyl having a double bond in the molecule and having a whole branch.

The fluorine leveling agent not only improves the leveling property but also has good orientation properties to the surface of the hard coat layer and has excellent surface modification effect even with a small amount of addition such as wettability of the hard coat layer.

As the fluorine leveling agent preferably used in the present invention, there can be mentioned, for example, commercially available ftergent 681 (trade name) (manufactured by NEOS Corporation) and ftergent 602A (trade name) manufactured by NEOS Corporation .

In the present invention, a leveling agent such as fluorine-based, acrylic-based, siloxane-based, etc. may be used in combination as long as the desired effect is not impaired.

In the present invention, the preferable amount of the leveling agent is 0.03 parts by weight to 3.0 parts by weight based on 100 parts by weight of the ionization curing resin. When the blending amount of the leveling agent is 0.03 parts by weight or less, a sufficient surface adjusting action can not be obtained and the improvement of the interference fringe deteriorates. If the blending amount of the leveling agent exceeds 3.0 parts by weight, a sufficient hard coatability is hardly obtained because the content of the uncured component contained in the hard coat layer is large, and the presence level of the leveling agent on the hard coat surface becomes too high. May not be obtained in some cases.

In the present invention, the water contact angle of the surface of the hard coat layer is 70 degrees or less. If the water contact angle of the hard coat layer is 70 degrees or less, blurring of the highly hydrophilic resin is preferable.

In the present invention, the hexadecane contact angle on the surface of the hard coat layer is 20 degrees or less. When the hexadecane contact angle of the hard coat layer is 20 DEG C or less, blurring to a resin having a high lipophilic property is favorable.

The hard coating film of the present invention having a contact angle defined by the above-described water and hexadecane has excellent wettability with respect to an adhesive used for a touch panel or the like. Therefore, even when a touch panel or the like is bonded to the surface of the hard coating layer through an adhesive , There is no wet cratering, and thus good adhesion can be exhibited.

Example

Hereinafter, the present invention will be described with reference to specific examples, but the present invention is not limited to the following examples.

≪ Example 1 >

A resin composition for forming a hard coat layer containing the following composition was applied on one side of one side of a triacetyl cellulose (TAC) film (trade name: KC4UAW, Konica Minolta Co.) using a bar coater, And dried for 60 seconds to form a hard coat layer having a thickness of 5 탆. This was cured at a UV irradiation dose of 200 mJ / cm < 2 > using a UV irradiator set at a height of 60 mm from the application surface to produce a hard coating film.

(A resin composition for forming a hard coat layer)

100 parts by weight of urethane acrylate (trade name: DIC-17-806, a multifunctional resin having a functional group number of 2 or more, manufactured by DIC Corporation), a photopolymerization initiator (trade name: Irgacure 184, BASF) , 0.1 part by weight of a fluorine leveling agent (trade name: Fotogen 681, manufactured by NEOS), 3.2 parts by weight of a N-CH ₃ type hindered amine photostabilizer (trade name: TINUVIN 292, And the mixture was diluted with ethyl acetate to a volatile content of 50% to obtain a coating material for a hard coat layer.

≪ Example 2 >

A hard coat film was prepared in the same manner as in Example 1 except that the amount of the fluorine leveling agent in Example 1 was changed to 0.25 parts by weight.

≪ Example 3 >

A hard coat film was prepared in the same manner as in Example 1 except that the amount of the fluorinated leveling agent in Example 1 was changed to 0.5 parts by weight.

<Example 4>

A hard coat film was prepared in the same manner as in Example 1 except that the amount of the fluorine leveling agent in Example 1 was changed to 1.0 part by weight.

&Lt; Example 5 >

A hard coat film was produced in the same manner as in Example 1 except that the amount of the fluorine leveling agent in Example 1 was changed to 3.0 parts by weight.

&Lt; Example 6 >

100 parts by weight of urethane acrylate used in Example 2 (trade name: DIC-17-806, manufactured by DIC Corporation, polyfunctional resin having a functional group number of 2 or more) was mixed with pentaerythritol triacrylate (trade name: Light Acrylate PE-3A , Kyoe Sangakagaku Co., Ltd., number of functional groups: 3) was changed to 100 parts by weight.

&Lt; Example 7 >

100 parts by weight of a urethane acrylate used in Example 2 (trade name: DIC-17-806, manufactured by DIC Corporation, polyfunctional resin having a functional group number of 2 or more) was dissolved in dipentaerythritol pentaacrylate (trade name: Light Acrylate DPE- 6A, manufactured by Kyoe Sagawa K.K., number of functional groups: 6) was changed to 100 parts by weight.

&Lt; Example 8 >

100 parts by weight of urethane acrylate used in Example 2 (trade name: DIC-17-806, manufactured by DIC Corporation, polyfunctional resin having a functional group number of 2 or more) was mixed with polypropylene dimethacrylate (trade name: NK Ester 9PG, Shin Nakamura Manufactured by Kagaku Co., Ltd., number of functional groups: 2) was changed to 100 parts by weight.

&Lt; Example 9 >

A hard coat film was prepared in the same manner as in Example 2 except that the fluorine leveling agent of Example 2 was changed to a fluorine leveling agent (trade name: Fotogen 602A, manufactured by Neos Corporation).

&Lt; Comparative Example 1 &

A hard coating film was produced in the same manner as in Example 1 except that the fluorine leveling agent of Example 1 was not blended.

&Lt; Comparative Example 2 &

A hard coating film was prepared in the same manner as in Example 1 except that the amount of the fluorine-based leveling agent in Example 1 was changed to 5.0 parts by weight.

&Lt; Comparative Example 3 &

A hard coat film was produced in the same manner as in Example 1 except that the leveling agent of Example 1 was changed to 0.25 parts by weight of a siloxane leveling agent (trade name: BYK310, manufactured by Big Chem Japan Co.).

&Lt; Comparative Example 4 &

A hard coat film was prepared in the same manner as in Example 1 except that the leveling agent of Example 1 was changed to 0.25 parts by weight of an acrylic leveling agent (trade name: Disperson LF-1984, manufactured by Sumitomo Chemical Co., Ltd.).

<Evaluation>

The hard coating films of Examples and Comparative Examples prepared as described above were evaluated for the following items, and the results are summarized in Table 1. &lt; tb &gt; &lt; TABLE &gt;

&Lt; Measurement of water contact angle and hexadecane contact angle >

Using a fully automatic contact system DM-701 manufactured by Kyowa Chemical Industry Co., Ltd., 1 μL of water or hexadecane was dropped, and the contact angle after 30 seconds was measured.

&Lt; Evaluation of interference pattern (iris color) >

The hard coating film obtained in Examples and Comparative Examples was cut out in an area of 10 cm x 15 cm to prepare a sample film. A black glossy tape was bonded to the surface opposite to the hard coat layer of the sample film. Using a three-wavelength type main white fluorescent lamp (National Palux, FL 15EX-N 15W) as a light source, The reflected light was visually observed.

○: No interference stripes are seen.

?: A level where interference streaks are slightly seen but there is no practical problem.

X: The interference stripes are very noticeable.

<Evaluation of scratch resistance>

The scratch on the hard coated surface when the hard coating side of the hard coating film was reciprocated for 10 rounds while pressing a steel wool # 0000 (made by Nippon Steel Mill Co., Ltd.) having a diameter of 25 mm at 1000 gf was measured with a three-wavelength type main white fluorescent lamp (National Palik, FL 15EX- N 15W) was used as a light source, and the reflected light was visually observed from above at an oblique angle.

○: No scratches are seen.

?: A level with scratches but no practical problems.

X: The scratches are very noticeable.

&Lt; Wettability of resin &

On the hard coating layer of the hard coating film, 0.7 g of U-2110 (manufactured by Chemistat Co., Ltd.) was dropped as a resin for an adhesive containing an ultraviolet curable acrylic monomer, and the diameter of the droplets after 5 minutes was measured.

: The diameter of the droplet was 35 mm or more (sufficient adhesion was obtained)

DELTA: The diameter of the droplet was 30 to 34 mm (variation in adhesive force occurred)

X: The diameter of the droplet is 30 mm or less (adhesion is insufficient)

According to the present invention, as apparent from Examples 1 to 9 shown in Table 1, it is possible to provide a hard coating layer containing a leveling agent in a hard coating layer and having a contact angle of water of 70 degrees or less and a contact angle of hexadecane of 20 degrees or less, In the case of a coated film, a hard coat film having a sufficient wettability of the hard coat layer and the resin and having sufficient scratch resistance without any problem of interference fringe can be obtained.

However, in Comparative Example 1 in which the leveling agent is not blended, the interference fringe is poor and the leveling agent is contained as shown in Comparative Example 2. When the contact angle of the surface of the hard coat layer deviates from the numerical value of the present invention, It is not suitable for use as a substrate for bonding. Further, since the amount of the leveling agent added was large, expected scratch resistance was not obtained. In addition, as shown in Comparative Example 3 and Comparative Example 4, a leveling agent of a different kind from the Examples was contained, and the contact angle of the surface of the hard coat layer was different from that of the present invention in Comparative Example 3 in both water and hexadecane, In Comparative Example 4, when the water contact angle deviates from the numerical value of the present invention, the wettability of the surface of the hard coat layer is insufficient, and thus it is not suitable for use as a base material for bonding.

Claims (5)

A hard coating film comprising a hard coat layer containing an ionization curing resin and a leveling agent formed on at least one side of a base film, characterized in that the contact angle of water on the surface of the hard coating layer is not more than 70 degrees and the contact angle of hexadecane is not more than 20 degrees Lt; / RTI &gt; The hard coating film according to claim 1, wherein the leveling agent is a fluorine-based compound. The hard coating film according to claim 1 or 2, wherein the amount of the leveling agent is 0.03 part by weight to 3.0 parts by weight based on 100 parts by weight of the ionization curing resin. The hard coat film according to any one of claims 1 to 3, wherein the ionization curing resin contains a polyfunctional acrylate and / or a urethane oligomer. The hard coating film according to any one of claims 1 to 4, wherein the base film is a cellulose-based film.