KR20150079079A - Optical Film - Google Patents

Abstract

The present invention provides an optical film in which surface energy is 30 to 50 mN/m as a film for treating surfaces of a polarizing plate, which easily transfers an anti-static agent from an adhesion layer of a film for protecting the polarizing plate. According to the present invention, the optical film can prevent adulteration of foreign substances and damage of a panel caused by static elasticity generated when the film for protecting the polarizing plate is detached.

Description

Optical Film {Optical Film}

The present invention relates to an optical film, and more particularly, to an optical film from which an antistatic agent can be easily transferred from a polarizing plate protective film.

BACKGROUND ART [0002] Liquid crystal display devices (LCDs), which have been used in various applications such as notebook computers, mobile phones, and liquid crystal TVs, generally include a liquid crystal cell containing a liquid crystal, an upper plate and a lower plate polarizer, And an adhesive layer. The polarizer includes a polarizer (or a polarizing film) in which a iodine compound or a dichroic polarizing material is adsorbed and oriented on a polyvinyl alcohol (PVA) resin film arranged in a predetermined direction, and a polarizer A first polarizer protective film such as triacetyl cellulose (TAC) for protecting the polarizer, a pressure-sensitive adhesive layer and a release film to be bonded to the liquid crystal cell on the first polarizer protective film. On the other side of the polarizer, a second polarizer protective film and a surface protective film in which a pressure-sensitive adhesive layer is laminated on the polyester-based substrate film on the second polarizer protective film are provided. At this time, the second polarizer protective film is arranged on the viewer side in the upper plate polarizer and on the backlight side in the lower plate polarizer. Further, on the second polarizer protective film of the top plate polarizer, a functional coating layer such as antireflection, antiglare, hardness and antistatic is further included depending on the application.

After the polarizing plate having such a structure is attached to the liquid crystal cell of the liquid crystal display device to manufacture a panel, an unnecessary surface protective film in the assembling process is peeled off together with the pressure sensitive adhesive layer laminated on the surface protective film, and static electricity is generated. Such static electricity causes surface contamination problems such as foreign matter adsorption on the optical member and stain problems due to unnecessary liquid crystal alignment. Further, the frictional static electricity generated between the lower plate polarizer and the backlight unit after the surface protective film is peeled affects the orientation of the liquid crystal, causing a defect, and there is a fear of causing breakage of the integrated circuit chip of the liquid crystal display device. Particularly, in recent years, as the size and thickness of a liquid crystal display panel become larger, the size of a polarizing plate used in the production of a liquid crystal display also increases and the speed of the process progresses. Further, the liquid crystal cell in which the backlight unit and the polarizing plate are stacked is closely arranged, and the amount of frictional static electricity generated between the backlight unit and the lower plate polarizing plate is further increased by deformation due to high temperature.

In order to solve the problem of static electricity at the time of peeling and peeling off of the surface protective film as described above, Korean Patent Laid-Open Publication No. 2009-0101761 discloses a method for producing a pressure sensitive adhesive composition comprising an antistatic agent and a pressure sensitive adhesive layer comprising the pressure sensitive adhesive composition Discloses a method of applying a polarizing plate protective film to a polarizing plate and transferring the antistatic agent to a cellulose-based film as a second polarizing protective film of the polarizing plate.

However, depending on the surface properties of the polarizing plate surface-treated film including the cellulose-based film to which the antistatic agent is transferred, transfer of the antistatic agent is difficult, resulting in contamination of foreign matter or damage to the panel.

Korea Patent Publication No. 2009-0101761

An object of the present invention is to provide a polarizing plate surface-treated film which is easy to transfer an antistatic agent from a pressure-sensitive adhesive layer of a polarizing plate protective film.

Another object of the present invention is to provide a polarizing plate in which the surface treatment film is laminated.

It is still another object of the present invention to provide an image display device including the polarizing plate.

On the other hand, the present invention provides an optical film having a surface energy of 30 mN / m to 50 mN / m, wherein the polarizing plate protective film is attached.

The optical film according to one embodiment of the present invention is characterized in that the excitation voltage of the polarizing plate protective film is 300 V or less.

On the other hand, the present invention provides an optical laminate to which a polarizing plate protective film is attached, which comprises a pressure-sensitive adhesive layer formed from a pressure-sensitive adhesive composition containing an antistatic agent in the optical film.

On the other hand, the present invention provides a polarizing plate in which the optical film or the optical laminate is laminated.

On the other hand, the present invention provides an image display device including the polarizer.

The optical film according to the present invention facilitates transfer of the antistatic agent from the pressure-sensitive adhesive layer of the polarizing plate protective film by controlling the surface energy, thereby preventing the foreign matter from being mixed with the panel and damaging the panel due to the static electricity generated during peeling of the polarizing plate protective film.

Hereinafter, the present invention will be described in more detail.

An embodiment of the present invention relates to a polarizing plate surface-treated film which is easy to transfer an antistatic agent from a pressure-sensitive adhesive layer of a polarizing plate protective film, and relates to an optical film having a surface energy of 30 mN / m to 50 mN / m.

The optical film according to one embodiment of the present invention may be a polarizing plate surface treatment film to which a polarizing plate protective film is attached, but may not be limited thereto. Examples of the optical film include a polarizer protective film, a hard coating film, an antiglare film and an antireflection film.

In one embodiment of the present invention, the optical film is characterized in that the voltage applied to the polarizing plate protective film during peeling is 300 V or less.

An optical film according to one embodiment of the present invention includes a transparent substrate and a coating layer formed on the transparent substrate.

In one embodiment of the present invention, any plastic film having transparency can be used as the transparent substrate. Examples of the transparent substrate include cycloolefin-based derivatives having units of monomers including cycloolefins such as norbornene and polycyclic norbornene monomers, cellulose (including diacetylcellulose, triacetylcellulose, acetylcellulose butyrate, iso Propyl cellulose, butyryl cellulose, acetyl propionyl cellulose), ethylene vinyl acetate copolymer, polyester, polystyrene, polyamide, polyetherimide, polyacryl, polyimide, polyether sulfone, polysulfone, polyethylene , Polypropylene, polymethylpentene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetal, polyether ketone, polyether ether ketone, polyethersulfone, polymethyl methacrylate, polyethylene terephthalate, polybutyl Rheneterephthalate, polyether Renna phthalate, may be used polycarbonate, selected from the group consisting of polyurethane and epoxy, it can be used an undrawn, uniaxially or biaxially stretched film.

Among the above-exemplified transparent materials, monoaxially or biaxially oriented polyester films excellent in transparency and heat resistance, cycloolefin-based derivative films excellent in transparency and heat resistance and capable of coping with the enlargement of the film, or transparency and optical anisotropy A triacetylcellulose film is suitably used.

The thickness of the transparent substrate is not particularly limited, but is 8 to 1000 탆, preferably 40 to 100 탆. If the thickness of the transparent base material is less than 8 占 퐉, the strength of the film is lowered and the workability is lowered. If the thickness is more than 1000 占 퐉, the transparency is lowered or the weight of the polarizing plate is increased.

In one embodiment of the present invention, the coating layer can be formed by selecting an appropriate coating composition according to the type of the polarizing plate surface treatment film and applying the coating composition to the transparent base material.

For example, when the surface treatment film is an antiglare film, the coating composition of the present invention may include a light transmitting resin, a light transmitting particle, a surface modifying additive, a photoinitiator and a solvent.

The light transmitting resin is a photo-curable resin and may include a photocurable (meth) acrylate oligomer and / or a monomer.

As the photo-curable (meth) acrylate oligomer, epoxy (meth) acrylate, urethane (meth) acrylate and the like are generally used, and urethane (meth) acrylate is more preferable. Urethane (meth) acrylate can be produced by reacting a compound having a hydroxyl group in a molecule with a compound having a polyfunctional (meth) acrylate and an isocyanate group in the presence of a catalyst. Specific examples of the (meth) acrylate having a hydroxyl group in the molecule include 2-hydroxyethyl (meth) acrylate, 2-hydroxyisopropyl (meth) acrylate, 4-hydroxybutyl Caprolactone ring-opening hydroxyacrylate, pentaerythritol tri / tetra (meth) acrylate mixture, and dipentaerythritol penta / hexa (meth) acrylate mixture. Specific examples of the compound having an isocyanate group include 1,4-diisocyanatobutane, 1,6-diisocyanatohexane, 1,8-diisocyanatooctane, 1,12-diisocyanatododecane, Diisocyanato-2-methylpentane, trimethyl-1,6-diisocyanatohexane, 1,3-bis (isocyanatomethyl) cyclohexane, trans-1,4-cyclohexane diisocyanate, Diisocyanate, toluene-2,6-diisocyanate, xylene-1,4-diisocyanate, tetramethyl xylene-1, Diisocyanate, 1-chloromethyl-2,4-diisocyanate, 4,4'-methylenebis (2,6-dimethylphenyl isocyanate), 4,4'-oxybis (phenylisocyanate), hexamethylene diisocyanate Trifunctional isocyanate and trimethylolpropane adduct derived from toluene diisocyanate O it may be one or more selected from the group consisting of carbonate.

The monomer is typically a photocurable functional group having an unsaturated group such as a (meth) acryloyl group, a vinyl group, a styryl group or an allyl group in the molecule, and among these, a (meth) acryloyl group is more preferable.

Specific examples of the monomer having a (meth) acryloyl group include neopentyl glycol acrylate, 1,6-hexanediol (meth) acrylate, propylene glycol di (meth) acrylate, triethylene glycol di Acrylate, dipropylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylol ethane tri Acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, pentaerythritol tetra (Meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, (Meth) acrylate such as tripentaerythritol hexa (meth) acrylate, bis (2-hydroxyethyl) isocyanurate di (meth) acrylate, hydroxyethyl (Meth) acrylate, stearyl (meth) acrylate, tetrahydroperfuryl (meth) acrylate, isobutyl (meth) acrylate, Acrylate, phenoxyethyl (meth) acrylate, and isobonole (meth) acrylate.

The above-mentioned light-curable (meth) acrylate oligomer and monomer which are the light-transmitting resins may be used alone or in combination of two or more.

The light transmitting resin may be contained in an amount of 15 to 80 parts by weight based on 100 parts by weight of the entire coating composition. When the amount of the light-transmitting resin is less than 15 parts by weight, it may be difficult to improve the hardness sufficiently. When the amount is more than 80 parts by weight, coating properties may be poor.

The translucent particles used in the technical field can be used without any particular limitation as long as they are particles capable of imparting water repellency. Examples of the translucent particles include silica particles, silicone resin particles, melamine resin particles, acrylic resin particles, styrene resin particles, acryl-styrene resin particles, polycarbonate resin particles, polyethylene resin particles, Resin particles or the like can be used. The above-mentioned translucent particles may be used alone or in combination of two or more.

The average particle diameter of the light transmitting particles is preferably 1 to 10 mu m. When the average particle diameter of the light transmitting particles is less than 1 탆, it is difficult to form irregularities on the surface of the antiglare layer, resulting in lowering of the antiglare property. When the average particle diameter is more than 10 탆, the surface of the antiglare layer becomes coarse and visibility deteriorates.

The light transmitting particle may be contained in an amount of 0.5 to 30 parts by weight based on 100 parts by weight of the entire coating composition. If the amount of the light-transmitting particles is less than 0.5 parts by weight, the light-shielding property may be deteriorated. If the amount is more than 30 parts by weight, bleaching of the antiglare layer may be enhanced.

The surface modifying additive may be used without limitation as long as it is used in the art. For example, BYK-333, 307, 377, 3530, 3550 and the like may be used as a commercially available leveling agent, but the present invention is not limited thereto, and the transparency, You can review and use whatever is appropriate.

The surface modifying additive may be included in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the entire coating composition. If the amount is less than 0.1 parts by weight, the leveling property may be deteriorated and problems such as crater ring and Bernard cell may be caused, and physical properties such as slipperiness and scratching property may be deteriorated. The surface defects due to the leveling agent stains may be caused.

The photoinitiator can be used without limitation as long as it is used in the art. Methyl-1- [4- (methylthio) phenyl] 2-morpholinopropane-1-one, diphenyl ketone benzyldimethyl ketal, 2-hydroxy- , 4-hydroxycyclophenyl ketone, dimethoxy-2-phenylacetophenone, anthraquinone, fluorene, triphenylamine, carbazole, 3-methylacetophenone, At least one selected from the group consisting of ethoxyacetophenone, 4,4-diaminobenzophenone, 1-hydroxycyclohexyl phenyl ketone and benzophenone may be used.

When a benzophenone-based hydrogen recycle type photoinitiator is used as the photoinitiator, a photosensitizer may be used together with the photoinitiator to minimize the problem of volatility generated during the photopolymerization process and the oxygen problem.

Specific examples of the photosensitizer include amine (meth) acrylate, triethylamine, diethylamine, methyldiethanolamine, ethanolamine, isoamyl 4-dimethylaminobenzoate and the like. These may be used alone or in combination of two or more.

The photoinitiator may be included in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the coating composition. When the amount of the photoinitiator is less than 0.1 parts by weight, the curing rate is slow. When the amount of the photoinitiator is more than 10 parts by weight, cracks may be formed on the surface of the coating layer.

The solvent is not limited as long as it is used in the technical field and can be used. Specific examples of the solvent include alcohols such as methanol, ethanol, isopropanol, butanol, methylcellulose, ethylsorbose and the like, acetates such as ethyl acetate, propyl acetate, butyl acetate, methyl cellosolve acetate, ethyl cellosolve acetate, Propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, methoxybutyl acetate, methoxypentyl acetate and the like), ketone type (methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, diethyl ketone, , Hexane (heptane, heptane, octane etc.), benzene (benzene, toluene, xylene, etc.), and the like. The solvents exemplified above may be used alone or in combination of two or more thereof.

The solvent may be contained in an amount of 30 to 80 parts by weight based on 100 parts by weight of the total coating composition. If the amount of the solvent is less than 30 parts by weight, the coating is difficult because of high viscosity. If the amount of the solvent is more than 80 parts by weight, the curing process takes a long time and the cost is low.

The coating layer may be formed by applying the coating composition to one side of a transparent substrate film, drying the coated film, and UV-curing the coating composition. The thickness of the coating layer is preferably 1 to 20 mu m.

One embodiment of the present invention relates to an optical laminate to which the polarizing plate protective film is attached to the optical film described above.

The polarizer protective film comprises a pressure-sensitive adhesive layer formed from a pressure-sensitive adhesive composition containing a base film and an antistatic agent positioned on the base film.

The base film is not particularly limited, but a polyester film such as cellulose, polycarbonate or polyethylene terephthalate having transparency; Polyether-based films such as polyethersulfone; A polyolefin film such as polyethylene, polypropylene, a polyolefin having a cyclonanorbornene structure, or an ethylene propylene copolymer can be used.

The base film may be a single layer or a laminate of two or more layers. The thickness of the base film may be appropriately selected depending on the application, and is preferably 5 to 500 m, more preferably 15 to 100 m.

In addition, the base film may be subjected to a surface treatment or a primer treatment on one side or both sides in order to improve the adhesion of the base material to the pressure-sensitive adhesive, and an antistatic layer, an antifouling layer or the like may be provided.

The method for forming the pressure-sensitive adhesive layer on the base film as described above is not particularly limited. For example, a method of applying a pressure-sensitive adhesive on a surface of a base film directly using a bar coater or the like, A method in which the pressure-sensitive adhesive layer formed on the surface of the releasable substrate is transferred to the surface of the base film and aged. At this time, the thickness of the pressure-sensitive adhesive layer is preferably 2 to 100 占 퐉, more preferably 5 to 50 占 퐉. When the thickness of the adhesive film is out of the above range, it is difficult to obtain a uniform pressure-sensitive adhesive layer, resulting in uneven physical properties of the pressure-sensitive adhesive film.

The pressure-sensitive adhesive composition may include a polymer binder and an antistatic agent.

The polymeric binder may be a polyurethane resin; Polyester-based resin; Acrylic resin; Polyether-based resin; Cellulose based resin; Polyvinyl alcohol-based resin; Epoxy resin; Polyvinyl pyrrolidone type resin; Polystyrene type resin; Polyethylene glycol-based resin, pentaerythritol-based resin, and the like, or an inorganic binder such as silicate. These binders may be used alone or in combination of two or more. Among these, a polyurethane resin, a polyester resin, and an acrylic resin are particularly preferable. Most preferably, an acrylic resin is used.

The acrylic copolymer used in the present invention is not particularly limited as long as it is commonly used in the art, but it is preferable to use one or two or more kinds of acrylate and / or methacrylate having an alkyl group having 1 to 14 carbon atoms as a main component Acrylic polymer. (Meth) acrylate having an alkyl group having 1 to 14 carbon atoms and / or a methacrylate (hereinafter referred to as (meth) acrylate) having 50 to 100% by weight of an alkyl group having 1 to 14 carbon atoms as a main component Acrylic polymers may be used.

Specific examples of the (meth) acrylate having an alkyl group having 1 to 14 carbon atoms include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, s- (Meth) acrylate, isobutyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) (meth) acrylate, n-octyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (Meth) acrylate, and n-tetradecyl (meth) acrylate.

Other components such as a sulfonic acid group-containing monomer, a phosphoric acid group-containing monomer, a cyano group-containing monomer, a vinyl ester, and an aromatic vinyl compound in order to balance the adhesive performance so as to have a Tg of 0 DEG C or lower (usually -100 DEG C or higher) · Improvement in adhesion such as a component for improving heat resistance, a carboxyl group-containing monomer, an acid anhydride group-containing monomer, a hydroxyl group-containing monomer, an amide group-containing monomer, an amino group-containing monomer, an imide group-containing monomer, an epoxy group-containing monomer and a vinyl ether Or a component having a functional group acting as a crosslinking starting point can be suitably used. Other components may be used alone or in combination of two or more.

Examples thereof include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl Monomers containing a hydroxy group such as hydroxyethyleneglycol (meth) acrylate or 2-hydroxypropyleneglycol (meth) acrylate; And monomers containing carboxyl groups such as (meth) acrylic acid, acrylic acid dimer, itaconic acid, maleic acid, maleic anhydride or fumaric acid.

The antistatic agent is generally used in the art, and specifically, a quaternary ammonium ion, a metal oxide, a surfactant, a conductive polymer, or the like may be used.

The pressure-sensitive adhesive composition applied to the polarizing plate protective film used in the present invention may further comprise a multifunctional crosslinking agent, if necessary. The crosslinking agent acts to increase cohesion of the pressure-sensitive adhesive by reacting with a carboxyl group or a hydroxyl group. The polyfunctional crosslinking agent may be an isocyanate compound, an epoxy compound, an aziridine compound or a metal chelate compound.

The pressure-sensitive adhesive composition applied to the polarizing plate protective film used in the present invention may further include a silane-based coupling agent or a tackifier resin, if necessary.

The silane coupling agent may be at least one member selected from the group consisting of? -Glycidoxypropyltrimethoxysilane,? -Glycidoxypropylmethyldiethoxysilane,? -Glycidoxypropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, vinyltri Methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltriethoxysilane, γ- 3-isocyanatepropyltriethoxysilane, or? -Acetoacetatepropyltrimethoxysilane, etc. may be used alone or in combination of two or more.

One embodiment of the present invention relates to a polarizing plate in which the above-mentioned optical film or optical laminate is laminated.

The structure of the polarizing plate of the present invention is not particularly limited and may have a structure known in the art. For example, it may include a polarizer and a protective film formed on at least one side of the polarizer.

One embodiment of the present invention relates to an image display apparatus including the polarizer, particularly a liquid crystal display apparatus.

The image display apparatus of the present invention may further include configurations known in the art in addition to the polarizing plate.

Hereinafter, the present invention will be described more specifically with reference to Examples, Comparative Examples and Experimental Examples. It should be apparent to those skilled in the art that these examples, comparative examples and experimental examples are only for illustrating the present invention, and the scope of the present invention is not limited thereto.

Example 1: Preparation of antiglare film

15 parts by weight of urethane acrylate (product of Mitsunobu Co., Ltd., product of PU620), 15 parts by weight of pentaerythritol triacrylate, 2 parts by weight of silicone resin particles (Momentive), 30 parts by weight of butyl acetate, 30 parts by weight of ethyl acetate, 2.5 parts by weight of photoinitiator 0.5 parts by weight of a leveling agent (manufactured by BYK-CHEMA, BYK-333) were mixed using a stirrer and filtered using a PP filter to prepare a coating composition for forming an antiglare layer Respectively.

The coating composition for forming an antiglare layer was coated on a triacetylcellulose film to a thickness of 6 탆 and dried at 80 캜 for 2 minutes. Dried, and then irradiated with ultraviolet light at a light intensity of 400 mJ / cm ^{2 with} a high-pressure mercury lamp to cure it to prepare an antiglare film.

Example 2: Manufacture of antiglare film

An antiglare film was prepared in the same manner as in Example 1 except that trimethylolpropane triacrylate was used in place of pentaerythritol triacrylate and BYK-307 was used in place of BYK-333 as a leveling agent.

Example 3: Preparation of antiglare film

An antiglare film was prepared in the same manner as in Example 1, except that BYK-3530 was used in place of BYK-333 as a leveling agent.

Example 4: Preparation of antiglare film

An antiglare film was prepared in the same manner as in Example 1, except that BYK-3550 was used in place of BYK-333 as a leveling agent.

Example 5: Preparation of antiglare film

An antiglare film was prepared in the same manner as in Example 1 except that trimethylolpropane triacrylate was used in place of pentaerythritol triacrylate and BYK-3550 was used in place of BYK-333 as a leveling agent.

Comparative Example 1: Manufacture of antiglare film

An antiglare film was prepared in the same manner as in Example 1, except that BYK-371 was used in place of BYK-333 as a leveling agent.

Comparative Example 2: Manufacture of antiglare film

An antiglare film was prepared in the same manner as in Example 1, except that BYK-307 was used in place of BYK-333 as a leveling agent.

Comparative Example 3: Manufacture of antiglare film

An antiglare film was prepared in the same manner as in Example 1 except that polyethylene glycol diacrylate was used in place of pentaerythritol triacrylate and BYK-3550 was used in place of BYK-333 as a leveling agent.

Experimental Example 1:

(1) Surface energy

The surface energies of the antiglare films prepared in Examples 1-5 and Comparative Examples 1-3 were measured by using the KRUSS DSA100 and the Owen Wendt Model Respectively.

(2) Antifouling property

Antifouling properties of the antiglare films prepared in Examples 1-5 and Comparative Examples 1-3 were evaluated by using a marking pen on the coating layer side of the antiglare film and wiping with sabina, and the results were evaluated as follows.

O: Not very well. Well cleared. No pen left.

△: Increasingly written. Pen residue left.

X: Well written. Not erased.

(3) Protective Film Peeling Voltage

The antiglare films prepared in Examples 1-5 and Comparative Examples 1-3 and a polarizing plate protective film containing an antistatic agent were laminated to the pressure-sensitive adhesive using a laminate, peeled at a rate of 0.3 m / min, and subjected to an electrostatic voltmeter The peeling electrification voltage was measured.

Surface energy
(mN / m) Antifouling Protective film
Peeling electrification voltage Example 1 35 O 132.6 Example 2 35 O 148.3 Example 3 40 O 48.8 Example 4 45 O 23.7 Example 5 50 O 12.5 Comparative Example 1 25 X 672.4 Comparative Example 2 30 X 492.8 Comparative Example 3 55 △ 10.3

As shown in Table 1, when the surface energy of the optical film according to the present invention is in the range of 30 mN / m to 50 mN / m, the antistatic property is transferred upon peeling the polarizing plate protective film so that the peeling electrification voltage is 300 V or less, I could confirm. On the other hand, when the surface energy is as high as 55 mN / m, the peeling electrification voltage of the polarizing plate protective film is as low as 10.3 V, but the pen residue is found in the antifouling property, and the surface of the protective film adhesive and antistatic Stain was observed.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Do. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Accordingly, the actual scope of the invention is defined by the appended claims and their equivalents.

Claims (12)

An optical film having a surface energy of 30 mN / m to 50 mN / m. The optical film according to claim 1, wherein the polarizing plate protective film is a polarizing plate surface-treated film to which the polarizing plate protective film is attached. The optical film according to claim 1, which is a polarizer protective film, a hard coating film, an antiglare film or an antireflection film. The optical film according to claim 2, wherein a dielectric strength at the time of peeling the polarizing plate protective film is 300 V or less. An optical laminate having a polarizing plate protective film attached to the optical film according to any one of claims 1 to 4. The optical laminate according to claim 5, wherein the polarizer protective film comprises a pressure-sensitive adhesive layer formed from a pressure-sensitive adhesive composition containing an antistatic agent. A polarizing plate laminated with the optical film according to any one of claims 1 to 4. A polarizing plate in which the optical laminate according to claim 5 is laminated. A polarizing plate in which the optical laminate according to claim 6 is laminated. 8. An image display device comprising the polarizing plate according to claim 7. 9. An image display device comprising the polarizing plate according to claim 8. An image display device comprising the polarizing plate according to claim 9.