WO2013180392A1 - Optical film including functional coating layer, polarizing plate including same, and image display device - Google Patents

Abstract

The present invention relates to an optical film including a functional coating layer formed on an acrylic film and on at least one surface of the acrylic film and having a water-soluble resin and at least two types of particles with different average grain sizes, and to a polarizing plate including same.

Description

Optical film comprising a functional coating layer, a polarizing plate and an image display device comprising the same

The present invention relates to an optical film, a polarizing plate comprising the same, and an image display apparatus, which have a functional coating layer including a water-dispersible resin and two or more kinds of fine particles having different particle diameters in an acrylic film.

A conventional polarizing plate generally has a structure in which a triacetyl cellulose (TAC) film is laminated on both surfaces of a polyvinyl alcohol (PVA) polarizer.

However, TAC films are susceptible to moisture, causing durability problems due to dimensional changes over long periods of use. In order to compensate for this disadvantage, attempts have been made to apply a film having a high moisture resistance and low retardation properties such as cycloolefin resin or acrylic resin to a polarizing plate. In particular, it is known that an acrylic film may have advantages in terms of cost as well as optical properties and durability.

However, the acrylic film produced using the conventional acrylic resin only has a high surface frictional force, causing blocking (a phenomenon in which the film surface and the film surface meet and stick after the winding).

In order to solve this problem, a method of forming a film by compounding rubber particles or inorganic particles with an acrylic resin has been proposed. However, when rubber particles or inorganic particles are included in the acrylic resin, light scattering occurs due to the particles. Problems, such as a value increase and film extensibility, fell.

The present invention is to solve the above problems, by providing a functional coating layer with a low friction coefficient on one surface of the acrylic film, it is possible to smooth running and winding of the film without impairing the transparency of the optical film and excellent anti-blocking properties To provide an optical film and a polarizing plate and an image display device including the same.

To this end, the present invention provides an optical film including an acrylic film and a functional coating layer formed on at least one surface of the acrylic film, and including a water-dispersible resin and two or more kinds of fine particles having different average particle diameters.

In another aspect, the present invention provides a polarizing plate and an image display device including the optical film of the present invention.

The acrylic film of the present invention is formed on the surface of the functional coating layer containing two or more kinds of fine particles having different particle diameters, excellent slip properties, excellent anti-blocking properties, and also excellent physical properties such as transparency and stretchability.

Hereinafter, preferred embodiments of the present invention will be described. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below. In addition, the embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art.

The present inventors have conducted research to develop an acrylic optical film having excellent slip properties and anti-blocking properties without impairing optical properties and elongation, and as a result, have a functionality including two or more fine particles having different average particle diameters on the acrylic film surface. By forming the coating layer, the inventors have found that an optical film excellent in all of optical properties, elongation property, slip property and antiblocking property can be produced.

The optical film of the present invention is formed on at least one surface of the acrylic film and the acrylic film, and includes a water-dispersible resin and a functional coating layer containing two or more kinds of fine particles having different average particle diameters.

The fine particles of the present invention are characterized by using two or more kinds of fine particles having different average particle diameters. By using two or more kinds of fine particles having different average particle diameters as described above, irregularities are appropriately formed on the surface of the functional coating layer, and in particular, the frictional force on the contact surface between the acrylic film and the functional coating layer and / or the functional coating layer can be effectively reduced. As a result, the blocking inhibiting ability can be further excellent.

More specifically, as the size of the fine particles increases, the surface unevenness of the functional coating layer increases, thereby improving the blocking inhibitory effect and the frictional force reducing effect. However, as the size of the fine particles increases, the haze generated by the fine particles also increases, so the size of the fine particles must be adjusted at an appropriate level.

At this time, in the case of using two or more kinds of fine particles having different average particle diameters, fine particles having a small particle size are suitably mixed between particles having a relatively large particle size to suppress haze generation and at the same time obtain an excellent blocking inhibitory ability and a frictional force reducing effect.

On the other hand, since the surface unevenness of the functional coating layer increases as the size of the fine particles increases, the thickness of the normal functional coating layer is 50 to 2000 nm, so that the size of the fine particles is 151 to 400 nm in order to form surface unevenness having an excellent effect. Is preferably. At this time, it is especially preferable to mix and use the fine particles having an average particle diameter of 20 to 150 nm, rather than to use the fine particles having a uniform average particle diameter alone.

That is, the two or more kinds of fine particles include the first fine particles having an average particle diameter of 20 to 150 nm and the second fine particles having an average particle diameter of 151 to 400 nm, and the average particle size difference between the two fine particles is preferably 50 to 380 nm. And the first fine particles having an average particle diameter of 50 to 150 nm and the second fine particles having an average particle diameter of 200 to 350 nm, and more preferably having an average particle size difference of 50 to 300 nm. In the case of containing fine particles having an average particle diameter of less than 20 nm, the surface unevenness forming effect is insignificant, and in the case of containing fine particles having an average particle diameter of more than 400 nm, light in the visible region is scattered largely, and therefore, it is not suitable as an optical film. In consideration of the normal particle size distribution, when the average particle size difference of the two fine particles is less than 50 nm, the particle size distribution of the two fine particles overlaps each other, so that the effect of using two different types of fine particles is unlikely to be expressed.

On the other hand, the first and second fine particles may have a weight ratio of 20/80 to 80/20, preferably 30/70 to 70/30. If it is out of the above range, the surface irregularities are formed to a similar extent as the case of using the fine particles having a uniform particle size alone, it is possible to suppress the haze generation and at the same time can not obtain excellent blocking inhibitory ability and frictional force reducing effect.

In the present invention, any appropriate fine particles can be used as the fine particles, and preferably water-dispersible fine particles can be used. For example, inorganic fine particles and / or organic fine particles can be used. Examples of the inorganic fine particles include inorganic oxides such as silica, titania, alumina, zirconia, zinc oxide, and antimony, and the like, and the organic fine particles can be, for example, silicone resins, fluorine resins, (meth) acrylic resins, and crosslinks. Polyvinyl alcohol, melamine type resin, etc. can be used.

Among these, silica is particularly preferable. Silica has more excellent blocking inhibitory ability, has better transparency, less haze, no coloration, less influence on optical properties of acrylic film, and better dispersibility and dispersion stability for coating layer composition. This is because workability is also superior. Specifically, the silica is more preferably colloidal silica. As colloidal silica, a commercially available product can be used as it is, for example, Snowtex series manufactured by Nissan Chemical Industries, Ltd., AEROSIL series by Air Products, Epostar series by Japan Catalyst and Soliostar RA series, Ranco LSH series can be used.

Next, the functional coating layer of the present invention is characterized in that it comprises a water-dispersible resin. In the case of containing a water-dispersible resin other than a solvent-based resin as described above, in a base film lacking solvent resistance such as an acrylic film, it does not cause a decrease in mechanical properties or surface defects due to erosion of the solvent and is uniformly coated. This is possible. In addition, it can be coated in-line (in-line) when manufacturing the film because it is environmentally friendly and does not require a separate explosion-proof equipment.

On the other hand, the water-dispersible resin of the present invention is not limited thereto, and examples thereof include water-dispersed polyurethane resins, water-dispersible acrylic resins, and combinations thereof.

In this case, the polyurethane-based resin, which may be used as the water-dispersible resin, preferably has a weight average molecular weight of 10,000 to 1 million. If the molecular weight is less than 10,000, there is a problem of adhesion, if it exceeds 1 million, there is a difficulty in producing a water-based polyurethane resin.

In addition, the polyurethane-based resin preferably contains a carboxyl group. When the carboxyl group is included in the polyurethane-based resin, the polyurethane-based resin is formed to form an anion part so as to be dispersed in water, thereby increasing the adhesion to the polarizer.

The polyurethane resin containing the carboxyl group can be obtained, for example, by reacting a chain extender having a free carboxyl group in addition to the polyol and polyisocyanate. The chain extender which has a carboxyl group is dihydroxy carboxylic acid, dihydroxy succinic acid, etc. are mentioned. Examples of the dihydroxy carboxylic acid include dialkylol alkanoic acid including dimethylol alkanoic acid such as dimethylol acetic acid, dimethylol butanoic acid, dimethylol propionic acid, dimethylol butyric acid and dimethylolpentanoic acid. These can be used individually or in combination of 2 or more types.

In addition, the said polyurethane-type resin is obtained by making a polyol and polyisocyanate react. The polyol is not particularly limited as long as it has two or more hydroxyl groups in the molecule, and any appropriate polyol can be employed. For example, the polyol may be a polyester polyol, polycarbonate diol, polyether polyol, or the like, and may be used alone or in combination of two or more kinds selected from the group consisting of these.

In this case, the polyester polyol may be obtained by reacting a polybasic acid component and a polyol component. As the polybasic acid component, for example, ortho-phthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, non Aromatic dicarboxylic acids such as phenyldicarboxylic acid and tetrahydrophthalic acid; Aliphatic dicarboxylic acids such as oxalic acid, succinic acid, malonic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, linoleic acid, maleic acid, fumaric acid, mesaconic acid and itaconic acid; Alicyclic dicarboxylic acids such as hexahydrophthalic acid, tetrahydrophthalic acid, 1,3-cyclohexanedicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid; Or reactive derivatives such as acid anhydrides, alkyl esters, and acid halides thereof. These can be used individually or in combination of 2 or more types.

On the other hand, the polyol is ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, 1,6-hexanediol, 1 , 8-octanediol, 1,10-decanediol, 4,4'-dihydroxyphenylpropane, 4,4'-dihydroxymethylmethane, diethylene glycol, triethylene glycol, polyethylene glycol, dipropylene glycol, Polypropylene glycol, 1,4-cyclohexanedimethanol, 1,4-cyclohexanediol, bisphenol A, bisphenol F, glycerin, 1,1,1-trimethylolpropane, 1,2,5-hexatriol, penta It is preferred that it is at least one selected from the group consisting of erytriol, glucose, sucrose, and sorbitol.

The polycarbonate diol is preferably an aliphatic polycarbonate diol. The polyurethane resin synthesized from such aliphatic polycarbonate diol is not only excellent mechanical properties but also excellent in water resistance and oil resistance, and particularly excellent in long-term weather resistance. On the other hand, the aliphatic polycarbonate diol, but is not limited to, for example, may be at least one selected from the group consisting of poly (hexamethylene carbonate) glycol and poly (cyclohexane carbonate) glycol.

The polyether polyol can be typically obtained by ring-opening polymerization of an alkylene oxide to a polyhydric alcohol. As a polyhydric alcohol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, glycerin, trimethylol propane, etc. are mentioned, for example. These can be used individually or in combination of 2 or more types.

On the other hand, the polyisocyanate is not limited as long as it is a compound having two or more NCO groups, for example, toluene diisocyanate (TDI), 4,4-diphenylmethane diisocyanate (MDI), 1,5-naphthalene diisocyanate (NDI ), Tolidine diisocyanate (TODI), hexamethylene diisocyanate (HMDI), isopron diisocyanate (IPDI), p-phenylene diisocyanate, 1,4-diisocyanate and xylene diisocyanate (XDI) It can be used individually or in combination of 2 or more types.

The method for producing the polyurethane-based resin may employ any suitable method known in the art. Specifically, the one-shot method which makes each said component react at once, and the multistage method which reacts in steps are mentioned. When a polyurethane-type resin has a carboxyl group, it is preferably manufactured by the multistage method, and it is because a carboxyl group can be introduce | transduced easily by the multistage method. Furthermore, any suitable urethane reaction catalyst can be used in the production of the polyurethane-based resin.

In the production of the polyurethane-based resin, other polyols and / or other chain extenders may be reacted in addition to the above components.

As another polyol, the polyol which has three or more hydroxyl groups, such as sorbitol, glycerin, trimethylol ethane, trimethylol propane, pentaerythritol, is mentioned, for example.

As another chain extender, for example, ethylene glycol, diethylene glycol, triethylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentylglycol, pentanediol, 1,6-hexane Glycols such as diol and propylene glycol; Aliphatic diamines such as ethylenediamine, propylenediamine, hexamethylenediamine, 1,4-butanediamine, and aminoethyl ethanolamine; Alicyclic diamines such as isophorone diamine and 4,4'-dicyclohexyl methanediamine; Aromatic diamine, such as xylylenediamine and tolylenediamine, etc. are mentioned.

Furthermore, a neutralizing agent can be used in manufacture of the said polyurethane resin. By using the neutralizing agent, the stability of the polyurethane-based resin in water can be improved. Examples of the neutralizing agent include ammonia, N-methylmorpholine, triethylamine, dimethylethanolamine, methyldiethanolamine, triethanolalkyne, morpholine, tripropylamine, ethanol amine, triisopropanolamine, and the like. These can be used individually or in combination of 2 or more types.

In the production of the polyurethane-based resin, an organic solvent which is inert to the polyisocyanate and compatible with water is preferably used. As said organic solvent, Ester solvent, such as ethyl acetate and an ethyl cellosolve acetate; Ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone; Ether solvents, such as dioxane tetrahydrofuran, etc. are mentioned. These can be used individually or in combination of 2 or more types.

Next, the water-dispersible acrylic resin that can be used as the water-dispersible resin may be prepared by polymerizing an acrylic monomer, and in this case, it is preferable to use an acrylic monomer having a glass transition temperature higher than room temperature. Although not limited thereto, it may include, for example, methyl methacrylate, ethyl methacrylate, isobutyl methacrylate or a mixture thereof.

In addition, the water-dispersible resin may further include at least one acrylic monomer having a glass transition temperature lower than room temperature. In this case, the adhesion and the physical properties of the functional coating layer can be improved, but is not limited thereto, for example, methoxyethylaminoacrylate, butyl acrylate, hexyl acrylate, ethylhexyl acrylate or a mixture thereof It may further include.

In addition, the water-dispersible resin may further include at least one or more water-soluble acrylic monomers. In this case, the storage stability of the acrylic monomer is improved, but is not limited thereto, and may further include, for example, hydroxyhexyl acrylate, hydroxyethyl acrylamide, methacrylic acid or a mixture thereof.

On the other hand, it is preferable that the functional coating layer of this invention contains 0.5-20 weight part of microparticles | fine-particles with respect to 100 weight part of water-dispersible resins, and it is more preferable that 0.5-10 weight part of microparticles | fine-particles are included with respect to 100 weight part of water-dispersible resins. . At this time, when the fine particles are contained in less than 0.5 parts by weight with respect to 100 parts by weight of the water-dispersible resin, there is no slip between films during winding, which may result in poor winding or film breakage. To produce a transparent film having a haze value of 0.3 or less.

Next, the optical film of the present invention uses an acrylic film as the base film. In this case, the acrylic film may be obtained by molding a molding material including (meth) acrylate resin as a main component by extrusion molding.

In the present invention, the (meth) acrylate-based resin is a resin comprising an acrylate-based unit and / or methacrylate-based unit as a main component, a homopolymer consisting of an acrylate-based unit or a methacrylate-based unit Not only the resin but also the copolymer resin in which other monomer units are copolymerized in addition to the acrylate unit and / or the methacrylate unit and the blend resin in which the other resin is blended in the above-mentioned (meth) acrylate resin.

The (meth) acrylate resins usable in the present invention are, for example, but not limited to, copolymer resins containing alkyl (meth) acrylate units and N-cycloalkyl maleimide units; A copolymer resin comprising an alkyl (meth) acrylate-based unit and a styrene-based unit; It may be a copolymer resin including an alkyl (meth) acrylate-based unit, an N-cycloalkyl maleimide unit and a styrene-based unit. In addition, it may be a blend resin containing such a copolymer resin and an aromatic resin having a carbonate portion in the main chain.

On the other hand, the alkyl (meth) acrylate-based unit means both alkyl acrylate-based unit and alkyl methacrylate-based unit, the alkyl group of the alkyl (meth) acrylate-based unit is preferably 1 to 10 carbon atoms, It is more preferable that it is C1-C4. In addition, the N-cycloalkyl group of the N-cycloalkyl maleimide unit preferably has 4 to 12 carbon atoms, and more preferably 5 to 8 carbon atoms. In addition, the styrene-based unit is not limited thereto, for example, styrene, α-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, 2- Methyl-4-chlorostyrene, 2,4,6-trimethylstyrene, cis-β-methylstyrene, trans-β-methylstyrene, 4-methyl-α-methylstyrene, 4-fluor-α-methylstyrene, 4- Chloro-α-methylstyrene, 4-bromo-α-methylstyrene, 4-t-butylstyrene, 2-fluorostyrene, 3-fluorostyrene, 4-fluorostyrene, 2,4-difluorostyrene, 2 , 3,4,5,6-pentafluorostyrene, 2-chlorostyrene, 3-talloworostyrene, 4-tallowostyrene, 2,4-dichlorostyrene, 2,6-dichlorostyrene, octachlorostyrene, 2 With bromostyrene, 3-bromostyrene, 4-bromostyrene, 2,4-dibromostyrene, α-bromostyrene, β-bromostyrene, 2-hydroxystyrene and 4-hydroxystyrene 1 selected from the group consisting of It may be more than one species, more preferably styrene, α-methyl styrene.

In addition, the (meth) acrylate-based resin may be a (meth) acrylate-based resin having a lactone ring structure, specific examples of the (meth) acrylate-based resin having a lactone ring structure, for example, (Meth) acrylate type resin which has a lactone ring structure as described in 2000-230016, Unexamined-Japanese-Patent No. 2001-151814, 2002-120326, etc. are mentioned.

In addition, the (meth) acrylate-based resin may be a (meth) acrylate-based resin having an aromatic ring, as (meth) acrylate-based resin having an aromatic ring (a) described in Korea Patent Publication No. 10-2009-0115040 A (meth) acrylate-based unit comprising at least one (meth) acrylate-based derivative; (b) an aromatic unit having a chain having an hydroxy group-containing portion and an aromatic moiety; (c) styrenic units comprising at least one styrene derivative; And (d) a ring-based unit having a ring portion. Each of the (a) to (d) units may be included in the resin composition in the form of a separate copolymer, and two or more units of the (a) to (d) units may be included in the resin composition in the form of one copolymer. have.

As a specific example, a copolymer comprising (a) units such as methyl (meth) acrylate and (d) units such as N-cyclohexylmaleimide, that is, poly (N-cyclohexylmaleimide-co-methyl (meth) ) Acrylate) can be used. In addition, a copolymer containing (c) units such as styrene and (d) units such as maleic anhydride can be used. Moreover, the copolymer containing methyl methacrylate as (a) unit, styrene and (alpha) -methyl styrene as (c) unit, and N-cyclohexyl maleimide as (d) unit can be used. Moreover, the copolymer containing methyl methacrylate as (a) unit, styrene or (alpha) -methyl styrene as (c) unit, and N-cyclohexyl maleimide and maleic anhydride as (d) unit can be used. However, the above examples are for illustrating the present invention, and the scope of the present invention is not limited to the above examples.

The method for producing the acrylic film is not particularly limited, and for example, (meth) acrylate-based resin and other polymers, additives, and the like are sufficiently mixed by any suitable mixing method to prepare a thermoplastic resin composition, which is then film-molded. Or (meth) acrylate-based resin and other polymers, additives and the like may be prepared in a separate solution and then mixed to form a uniform mixed solution and then film-molded.

The thermoplastic resin composition is prepared by, for example, extrusion kneading the resulting mixture after preblending the film raw material with an appropriate mixer such as an omni mixer. In this case, the mixer used for extrusion kneading is not specifically limited, For example, arbitrary appropriate mixers, such as an extruder, such as a single screw extruder and a twin screw extruder, and a pressurized kneader, can be used.

As a method of the said film shaping | molding, arbitrary suitable film shaping | molding methods, such as the solution casting method (solution casting method), the melt extrusion method, the calender method, the compression molding method, are mentioned, for example. In particular, the melt extrusion method is preferable.

The melt extrusion method is not particularly limited, and may be performed by a melt extrusion method well known in the art, for example, a T die method, an inflation method, or the like. At this time, molding temperature becomes like this. Preferably it is 150-350 degreeC, More preferably, it is 200-300 degreeC.

When forming a film by the said T-die method, a T die can be attached to the front-end | tip of a well-known single screw extruder or a twin screw extruder, the film extruded in film shape can be rolled, and a roll-shaped film can be obtained. Under the present circumstances, you may uniaxially stretch by extending | stretching to an extrusion direction using a stretch roll at appropriate temperature. Moreover, simultaneous biaxial stretching, sequential biaxial stretching, etc. can also be performed by extending | stretching a film in the direction perpendicular | vertical to an extrusion direction using transverse stretching machines, such as a tenter.

The acrylic film may be any of an unstretched film or a stretched film. In the case of a stretched film, it may be a uniaxial stretched film or a biaxially stretched film, and in the case of a biaxially stretched film, it may be either a simultaneous biaxially stretched film or a successive biaxially stretched film. In the case of biaxial stretching, the mechanical strength is improved and the film performance is improved.

On the other hand, when mixing and stretching other thermoplastic resins in the production of the acrylic film, it is possible to suppress the increase in the phase difference to maintain optical isotropy, on the contrary, in the production of the acrylic film, stretching by adding a phase anisotropy having a large anisotropy In this case, the phase difference can be greatly increased and used as a compensation film for a wide viewing angle.

The optical film of the present invention may be prepared by applying a composition for forming a functional coating layer on the surface of the acrylic film and then drying, wherein the coating is well known in the art, for example It may be performed using a bar, gravure, slot die coater.

In this case, the surface treatment may be performed on at least one surface of the acrylic film to improve the adhesion between the acrylic film and the functional coating layer, wherein the surface treatment is a method well known in the art, such as corona treatment or plasma treatment. It is available.

On the other hand, the drying step may be performed through a convection oven or the like, but is not limited thereto. Preferably, the drying step is performed for 10 seconds to 5 minutes at a temperature of 90 ℃ to 120 ℃. The drying temperature may be adjusted differently depending on the coating step.

More specifically, when the optical film of the present invention is an unstretched film or a film completed before the coating step, it is preferable to perform a drying step within a range not exceeding the glass transition temperature (Tg) of the film.

On the other hand, in the case of stretching the optical film of the present invention after coating, it may be stretched after drying for 10 seconds to 3 minutes at a temperature of 90 ~ 120 ℃ after coating, to be made at the stretching temperature and at the same time stretching It is also possible.

At this time, when the drying is performed simultaneously with the stretching, the stretching temperature is preferably the glass transition temperature (Tg) ~ (Tg + 30) ℃ of the acrylic resin composition of the present invention, more preferably (Tg + 2) ℃ ~ (Tg + 20) ° C. At this time, when the stretching temperature is less than Tg, breakage may occur in the stretching step of the optical film, and when the stretching temperature exceeds (Tg + 30) ° C., a flow of the resin composition occurs and there is a concern that the stretching of the optical film may not be stably performed. have.

On the other hand, in the present invention, the thickness of the functional coating layer is preferably 50nm to 2000nm, more preferably 100nm to 1000nm, still more preferably 200nm to 700nm. If the thickness of the functional coating layer is less than 50nm, there is a problem that the adhesive strength is not sufficient, if it exceeds 2000nm there is a problem that the drying is not enough or the water-dispersible fine particles are buried in the functional coating layer can not impart slip properties properly .

It is preferable that the optical film of the present invention has a surface friction coefficient of 0.6 or less, and when satisfying the above range, it provides an excellent slip property, and can effectively improve a winding failure such as winding wrinkles and blocking.

Moreover, it is preferable that the internal haze of the optical film of this invention is 0.5% or less. The internal haze is generated by light scattering such as internal fine particles, and the larger the value thereof, the lower the light transmittance of the manufactured polarizing plate. Therefore, when the optical film having a large internal haze value is applied to the LCD panel, the contrast ratio can be greatly reduced, so that the internal haze of the optical film of the present invention is preferably 0.5% or less, and more preferably 0.3% or less.

Moreover, this invention provides the polarizing plate containing the optical film of this invention mentioned above. An optical article such as a polarizing plate including the optical film according to the present invention has a good light transmittance of the optical film having the functional coating layer of the present invention, so that the light transmittance of the manufactured optical article does not occur, and the surface of the water-dispersible fine particles The unevenness | corrugation formed by this is formed and has the outstanding slipperiness | lubricacy.

Furthermore, the present invention provides various electronic devices such as an image display device including the optical film or the polarizing plate of the present invention. In this case, the electronic device may include various image display devices such as an LCD and a PDP, and the type is not limited thereto. The electronic device may have a configuration known in the art except for including an optical film having a functional coating layer according to the present invention.

Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1

After the poly (cyclohexylmaleimide-co-methylmethacrylate) (LGMMA PMMA830HR) resin was prepared using an T-die film making machine at 250 ° C. and 250 rpm, an unoriented acrylic film having a width of 800 mm was obtained at 135 ° C. Stretched 1.8 times in the MD direction at the temperature.

Water-dispersed polyurethane resin (aliphatic polycarbonate diol type, photocoating paint CK-PUD-PF: 30% solids aqueous solution) 31.75g, the first colloidal silica (average particle diameter 70nm, 20% solids aqueous solution) 1.19g, first 2. A functional coating solution was prepared by mixing 1.19 g of 2 colloidal silica (average particle diameter 200 nm, 20% solids aqueous solution) and 65.87 g of pure water.

The acrylic film stretched in the MD direction was subjected to corona treatment under the condition of 50 W / m ² / min. It was coated with the functional coating solution prepared above # 3 Mayer bar (Meyer bar) and dried for 3 minutes at 90 ℃ hot air. Finally, the film was stretched 2.4 times in the TD direction at a temperature of 135 ° C. to prepare an optical film (50 μm thick) including a 300 nm thick functional coating layer.

Example 2

Water-dispersed polyurethane resin (aliphatic polycarbonate diol type, photocoating paint CK-PUD-PF: solid content 30% aqueous solution) 31.75g, the first colloidal silica (average particle diameter 100nm, solid content 20% aqueous solution) 0.71g, first An optical film having a functional coating layer was prepared in the same manner as in Example 1, except that 1.67 g of 2 colloidal silica (average particle diameter 300 nm, 20% solids aqueous solution) and 65.87 g of pure water were prepared.

Example 3

Water-dispersed polyurethane resin (aliphatic polycarbonate diol type, photocoating paint CK-PUD-PF: solid content 30% aqueous solution) 31.15 g, the first colloidal silica (average particle diameter 70nm, solid content 20% aqueous solution) 2.34g, first An optical film having a functional coating layer was prepared in the same manner as in Example 1, except that 0.93 g of 2 colloidal silica (average particle diameter 300 nm, 20% solid content aqueous solution) and 65.58 g pure water were mixed.

Comparative Example 1

Water-dispersed polyurethane resin (aliphatic polycarbonate diol type, dimmer paint CK-PUD-PF: solid 30% aqueous solution) 31.15 g, colloidal silica (solid 20% aqueous solution) 3.27 g, pure water 65.58 g An optical film having a functional coating layer was prepared in the same manner as in Example 1, except that the functional coating solution was prepared by mixing.

Comparative Example 2

An optical film having a functional coating layer was prepared in the same manner as in Comparative Example 1 except that colloidal silica having an average particle diameter of 50 nm was used.

Experimental Example

1. internal haze

The surface coated with the functional coating layer was coated with PVA adhesive (Japan Synthetic Chemical Gohsefimerz-200, 4% aqueous solution) using # 9 Mayer bar, and dried in an oven at 90 ° C. for 5 minutes, followed by Hazemeter (Murakami , Internal haze was measured with HM-150). The measurement results are shown in the following [Table 1].

2. Static friction coefficient

The static friction coefficient was determined by measuring the frictional force between the surface coated with the functional coating layer and the opposite surface by the ASTM D 1894 test method. Measurement conditions were carried out at a speed of 180mm / min with a weight of 500g. The measurement results are shown in the following [Table 1].

3. Anti-blocking property

After slitting both ends of the films produced in Examples 1 to 3 and Comparative Examples 1 and 2, the film rolls are wound by winding on a roll of 500 m or more. The wound state of the film and the roll appearance change after 1 week or more were visually confirmed to evaluate the antiblocking property as follows. The measurement results are shown in the following [Table 1].

O (good): The film is wound without wrinkles and does not deform or stick together in appearance even after being left for one week or longer.

X (poor): The appearance is deformed or the film sticks to each other after wrinkles or standing on winding.

Table 1 Base Film Functional coating layer composition (after drying) Measurement result Water Dispersed Polyurethane Resin Content (parts by weight) First particulate Second particulate Internal haze (%) Static friction coefficient Anti blocking property Average particle diameter (nm) Content (parts by weight) Average particle diameter (nm) Content (parts by weight) Example 1 Oriented acrylic film 100 70 2.5 200 2.5 0.2 0.45 O Example 2 100 1.5 300 3.5 0.3 0.41 O Example 3 70 5 300 2 0.3 0.43 O Comparative Example 1 300 7 - - 0.6 0.38 O Comparative Example 2 50 7 - - 0.2 0.81 X

According to the experimental data, in the case of Comparative Example 1 using one type of colloidal silica having an average particle diameter of 300 nm, the internal haze was high as 0.6%, which was not suitable for use as a protective film for polarizing plates.

In addition, Comparative Example 2 using one type of colloidal silica having an average particle diameter of 50 nm had a slightly higher static friction coefficient of 0.81, causing wrinkles upon winding, and worsening of wrinkles even after standing, and thus, it was determined that the antiblocking property was poor. .

Meanwhile, in Examples 1 to 3, the internal Haze was good at 0.3% or less, and all of the static friction coefficients were 0.6 or less, and the anti-blocking property was good.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and changes can be made without departing from the technical spirit of the present invention described in the claims. It will be obvious to those of ordinary skill in the field.

Claims (11)

Acrylic film; And An optical film formed on at least one surface of the acrylic film, and including a functional coating layer containing a water-dispersible resin and two or more kinds of fine particles having different average particle diameters. The method of claim 1, Said two or more types of microparticles | fine-particles are the 1st microparticles | fine-particles which have an average particle diameter of 20-150 nm, and the 2nd microparticles | fine-particles which have an average particle diameter of 151-400 nm, and the optical film whose average particle diameter difference of two microparticles | fine-particles is 50-380 nm. The method of claim 2, The optical film having a weight ratio of the first fine particles and the second fine particles 20/80 to 80/20. The method of claim 1, The fine particles are colloidal silica. The method of claim 1, The water-dispersible resin is an optical film of water-dispersed polyurethane resin, water-dispersible acrylic resin or a combination thereof. The method of claim 1, The functional coating layer is 0.5 to 20 parts by weight of fine particles with respect to 100 parts by weight of water-dispersible resin. The method of claim 1, The functional coating layer is an optical film having a surface friction coefficient of 0.6 or less. The method of claim 1, The functional coating layer has an internal haze of less than 0.5% optical film. The method of claim 1, The optical film is an optical film which is a protective film for a polarizing plate. The polarizing plate containing the optical film of any one of Claims 1-9. An image display device comprising the polarizing plate of claim 10.