KR20190085653A - Coationg composition, manufacturing method of polarizer protecting film using same, polarizer protecting film, polarizing plate comprising same and liquid crystal display device comprising same - Google Patents

Abstract

The present invention relates to a coating composition comprising: a cationic thermosetting resin; wax powder; and a cationic thermosetting agent, to a production method of a polarizer protective film using the same, and to a polarizer protective film produced thereby, wherein the polarizer protective film has high surface hardness and scratch resistance.

Description

TECHNICAL FIELD [0001] The present invention relates to a coating composition, a polarizer protective film using the same, a polarizer protective film, a polarizer including the polarizer protective film, and a liquid crystal display device including the polarizer protective film. CRYSTAL DISPLAY DEVICE COMPRISING SAME}

The present invention relates to a coating composition, a method for producing a polarizer protective film, a polarizer protective film, a polarizing plate including the polarizer protective film, and a liquid crystal display device including the polarizer protective film, which can exhibit excellent physical and optical characteristics, To a polarizer protective film.

BACKGROUND ART [0002] Liquid crystal display devices are widely used from cellular phones and portable electronic devices to personal computers and large-sized electronic devices such as televisions, and their use is one of the ever-expanding flat panel displays. Since such a liquid crystal display device is not a self-luminous type device, a light source such as a backlight unit is usually placed on the back of a lower polarizer plate provided on the lower side of the liquid crystal cell, and the light emitted from the light source is transmitted through the liquid crystal cell, So that an image is displayed.

In recent years, a large load has been applied to the central portion of the liquid crystal cell, and a sagging phenomenon of the lower polarizer is generated. Thus, the polarizer protective film of the lower polarizer attached to the liquid crystal cell And the lower polarizing plate is caught by the diffusion sheet on the surface of the backlight unit. To solve this problem, a method of coating a hard coating layer on a protective film of a lower polarizer plate has been proposed, but there is a problem of an increase in process cost.

According to this necessity, development of a method of preventing the lower polarizer plate from being damaged while reducing the cost of the process and having price competitiveness is required.

Korean Laid-Open Publication No. 2012-0107256

Disclosed is a polarizer protective film of a lower polarizer. The polarizer protective film has excellent coating properties, a high surface hardness and a scratch resistance, a polarizer having excellent physical and optical properties, A liquid crystal display device is provided.

One embodiment of the present application relates to a curable thermosetting resin; Wax powder; And a cationic thermosetting agent.

Another embodiment provides a method of manufacturing a semiconductor device, comprising: preparing a substrate film; Applying a coating composition according to one embodiment of the present application on at least one side of a substrate film; And a step of stretching the base film coated with the coating composition.

Another embodiment includes a substrate film; And a coating layer comprising a coating composition according to an embodiment of the present application provided on one side or both sides of the base film.

Another embodiment includes a polarizer; And a polarizer protective film according to an embodiment of the present application on at least one side of the polarizer.

Finally, one embodiment of the present application relates to a liquid crystal cell comprising: a liquid crystal cell; An upper polarizer provided on an upper portion of the liquid crystal cell; A lower polarizer disposed on a lower portion of the liquid crystal cell; And a backlight unit provided on a lower portion of the lower polarizer, wherein the lower polarizer comprises a polarizer; And a polarizer protective film according to an embodiment of the present application disposed on one side or both sides of the polarizer.

The coating composition of the present invention can contain an appropriate amount of wax fine particles and can have an appropriate hardness without using an inorganic or organic particle additive, maintain moldability such as stretchability, maintain high transmittance, ). When the polarizer protective film is used as a polarizer protective film, a diffuser sheet or a prism sheet may have no cracks or scratches.

In addition, the coating composition of the present invention includes a thermosetting agent so that curing can be induced in a stretching process without a specific heat curing or UV curing process in the production of a polarizer protective film, .

In addition, since the polarizer protective film including the coating composition is used as a protective film of the lower polarizer, the polarizer protective film is damaged by abutting against the diffusion sheet on the surface of the backlight unit due to deflection of the lower polarizer, And can exhibit excellent optical properties.

1 is a view illustrating a liquid crystal display device according to an embodiment of the present invention.

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

The present invention relates to a polarizer protective film adjacent to a backlight unit of a lower polarizer plate provided in a lower layer portion of a liquid crystal cell in a liquid crystal display device and the polarizer protective film has a wax powder, Thereby providing an excellent polarizer protective film.

In addition, the polarizer protective film made of the coating composition of the present invention can prevent damage that may occur due to the sagging phenomenon of the lower polarizer.

1 shows an embodiment of a liquid crystal display device according to the present invention. The liquid crystal display device shown in Fig. 1 includes a liquid crystal cell 20; An upper polarizer plate 10 provided on an upper portion of the liquid crystal cell 20; A lower polarizer plate 30 provided on a lower portion of the liquid crystal cell 20; And a backlight unit 40 provided on a lower portion of the lower polarizer plate. The polarizer protection film 34 is provided on the lower polarizer plate 30 adjacent to the backlight unit.

In the present invention, the terms 'upper surface' and 'upper' mean a surface or a direction arranged toward a viewer side, that is, a viewer side when a polarizing plate is mounted on a device such as a liquid crystal display device. Conversely, 'under' and 'under' mean the face or direction opposite the viewer, that is, facing the backlight unit when the polarizer is mounted on the device.

Hereinafter, the coating composition, the polarizer protective film, the method for producing the polarizer protective film, the polarizer including the polarizer protective film, and the liquid crystal display including the polarizer will be described in detail.

In one embodiment of the present application, a cationic thermosetting resin; Wax powder; And a cationic thermosetting agent.

In one embodiment of the present application, the cationic thermosetting resin comprises an epoxy-based compound.

According to one embodiment of the present application, the weight average molecular weight of the epoxy compound is not particularly limited, but may be about 100 to 5,000 g / mol, or about 200 to 5,000 g / mol. If the weight average molecular weight of the epoxy compound is too large, the viscosity may be high and the coating property may be poor. If the weight average molecular weight is too small, the hardness is low.

The epoxy-based compound contains at least one epoxy group and is cured by the cation generated from the cationic initiator. As the binder, an aromatic epoxy compound, a hydrogenated epoxy compound, an alicyclic epoxy compound, an aliphatic epoxy compound , And preferably an alicyclic epoxy compound can be used.

In one embodiment of the present application, the epoxy compound is a coating composition which is an alicyclic epoxy compound.

In one embodiment of the present application, the alicyclic epoxy compound may be Celloxide 2021P, CELLOXIDE 2081 or S-28, but is not limited to the alicyclic epoxy compound.

The aromatic epoxy compound refers to an epoxy compound containing at least one aromatic hydrocarbon ring in the molecule and includes, for example, diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol F , Bisphenol-type epoxy resins such as diglycidyl ether of bisphenol S; Phenol novolak epoxy resin, cresol novolak epoxy resin, and hydroxybenzaldehyde phenol novolak epoxy resin, glycidyl ether of tetrahydroxyphenylmethane, glycidyl ether of tetrahydroxybenzophenone, epoxy And polyvinylphenol, and the like.

The hydrogenated epoxy compound refers to an epoxy compound obtained by selectively hydrogenating the aromatic epoxy compound under a pressure in the presence of a catalyst, but is not limited thereto. Of these, the hydrogenated bisphenol A It is preferable to use diglycidyl ether.

The alicyclic epoxy compound means an epoxy compound in which an epoxy group is formed between adjacent two carbon atoms constituting an aliphatic hydrocarbon ring, but is not limited thereto. For example, 2- (3, Epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 3,4,5- Epoxy-6-methylcyclohexylmethyl-3,4-epoxy-6-methylcyclohexanecarboxylate, vinylcyclohexanedioxide, bis (3,4-epoxycyclohexylmethyl) adipate, bis Epoxycyclohexylmethyl) adipate, exo-exobis (2,3-epoxycyclopentyl) ether, endo-exobis (2,3-epoxycyclopentyl) ether, 2,2-bis [4 - (2,3-epoxypropoxy) cyclohexyl] propane, 2,6-bis (2,3-epoxypropoxycyclohexyl-p-dioxane), 2,6- Bis (3,4-epoxycyclohexyl) propane, dicyclopentadienedioxide, 1,2-epoxy-6- (2,3-epoxypropoxy) (2,3-epoxy) cyclopentylphenyl-2,3-epoxypropyl ether, 1- (2,3-epoxypropoxy) phenyl-5,6- (2,3-epoxy) cyclopentylphenyl-2,3-epoxypropyl ether), 1,2-bis [5- (1,2-epoxy) -4 Ethanocyclopentenyl phenyl glycidyl ether, methylene bis (3,4-epoxycyclohexane) ethylene glycol di (3,4-epoxycyclohexylmethyl) ether, ethylene bis (3, Epoxycyclohexanecarboxylate), ε-caprolactone (1 to 10 mol) adduct of 3,4-epoxycyclohexanemethanol and poly (3 to 20) alcohol (GR, TMP, PE, DPE, Hexapentaerythritol), and the like. Among them, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate is particularly preferably used from the viewpoint of reactivity.

In one embodiment of the present application, the wax powder may be selected from the group consisting of Carnauba Wax, Fischer-Tropsch wax, Paraffin-wax, Amide wax, PE (polyethylene) wax, PP (polypropylene) wax or PTFE (polytetrafluoroethylene) wax But it is not limited to wax powder.

The wax may be in the form of a dispersion or a powder. The melting point of the wax may be 70 ° C or higher and 250 ° C or lower, and may be 350 ° C or higher for the PTFE type. .

In one embodiment of the present application, the wax powder is selected from the group consisting of Carnauba Wax, Fischer-Tropsch wax, Paraffin-wax, Amide wax, PE (polyethylene) wax, PP (polypropylene) wax, or PTFE (polytetrafluoroethylene) wax powder One or more wax powders may be mixed and used.

In one embodiment of the present application, the particle size of the wax powder may be 1 μm or more and 50 μm or less, preferably 1 μm or more and 30 μm or less, and more preferably 1 μm or more and 10 μm or less, based on D50.

When the particle size of the wax powder is in the above range, it has hardness maintenance and anti-blocking properties even at a low content, and since the particles do not become excessively larger than the thickness of the coating layer in the future, And when used as a polarizer protective film, it is particularly excellent in hardness and moldability, and has a property capable of suppressing the scratch of the polarizer.

The particle size of the wax powder is measured by laser diffraction. For example, a Horiba LA-950 Particle Size Analyzer may be used.

In one embodiment of the present application, the cationic thermosetting agent preferably has a thermosetting start temperature of 100 ° C or more and 180 ° C or less.

The cationic thermosetting agent means a compound which produces a cation or a Lewis acid by heat treatment and acts on a cationic polymerizable group such as an epoxy group to initiate a cationic polymerization reaction.

At this time, as the cationic thermosetting agent, cationic thermosetting agents commonly used in the art can be used without limitation. For example, a sulfonium salt, an ammonium salt, a phosphonium salt, an onium salt, an iodonium salt, and the like. Specific examples thereof include ammonium / antimony hexafluoride, triarylsulfonium hexafluoroantimonate salts, trianylsulfonium hexafluoroantimonate, (Tolylumil) iodonium tetrakis (pentafluorophenyl) borate, Bis (dodecylphenyl) iodonium hexafluoroantimonate, iodonium (4-methylphenyl) (4- (2-methylpropyl) phenyl) hexafluorophosphate, octyldiphenyliodonium hexafluoroantimonate Benzylpyridinium salts, N-benzylpyridinium salts, N-benzylammonium salts, phosphonium salts, hydrazinium salts, ammonium borate salts, triaryl iodonium salts, benzylsulfonium salts, phenacylsulfonium salts, Phenylmethyl chloride, and mixtures thereof. Preferred examples thereof include ammonium / antimony hexafluoride, trianylsulfonium hexafluoroantimonate, triphenylmethyl chloride, and the like. Products in the mountains - can be used such aid (San Aid) SI-B3, SI-360.

In one embodiment of the present application, the cationic thermosetting agent may include a sulfonium salt or an iodonium salt.

In one embodiment of the present application, the cationic thermosetting agent may be, but not limited to, tetrakis (pentafluorophenyl) borate, SbF6 anion type and hexafluorophosphate.

In one embodiment of the present application, the cationic thermosetting agent may be represented by the following structural formula.

In one embodiment of the present application, the cationic thermosetting agent is selected from the group consisting of San-Aid SI-B3 (benzyl (4-hydroxyphenyl) methylsulfonium, tetrakis (pentafluorophenyl) 4-hydroxyphenyl) methylsulfonium, tetrakis (pentafluorophenyl) borate (1: 1))).

In one embodiment of the present application, the coating composition comprises 0.05 to 30 parts by weight of the wax powder based on 100 parts by weight of the cationic thermosetting resin; And 0.01 to 10 parts by weight of the cationic thermosetting agent.

In one embodiment of the present application, the wax powder may be 0.05 to 30 parts by weight, preferably 0.05 to 20 parts by weight, more preferably 0.05 to 10 parts by weight, based on 100 parts by weight of the cationic thermosetting resin.

When the wax powder has the above-mentioned weight range, the dispersibility in the coating composition is particularly excellent, so that the coagulation of the wax powder can be prevented, and scratch can be suppressed when the wax powder is used as a polarizer protective film. It is possible to suppress the occurrence of the slip-off at the time.

In one embodiment of the present application, the amount of the cationic thermosetting agent is 0.01 to 10 parts by weight, preferably 0.05 to 5 parts by weight, more preferably 0.05 to 1 part by weight based on 100 parts by weight of the cationic thermosetting resin have.

When the thermosetting agent has the weight range, it is preferable that the thermosetting agent is excellent in stability in the state of the coating composition mixture, and the thermosetting agent is preferably an expensive raw material and includes the above weight range. In addition, if the thermosetting agent exceeds the above weight range, the curing rate in the stretching process can not be controlled and the stretchability can be inhibited.

In one embodiment of the present invention, the coating composition further comprises a silicon-based or fluorine-based compound.

Examples of the silicon-based compound include a non-reactive silicone compound having a silicon group such as dimethylsiloxane and methylsiloxane and containing an alkyl group, a polyether group or the like; Or a reactive silicone compound having a silicon group and containing a vinyl group, a (meth) acrylate group, or a (meth) acryloxy group; (Meth) acrylate group, a (meth) acryloxy group, and the like. The reactive silicone compound having a silicon group and containing a vinyl group, a (meth) acrylate group, Can be used.

Examples of the fluorine compound include a non-reactive fluorine compound having a fluorine group such as a fluoroalkyl group; Or a reactive fluorine compound having a fluorine group and containing a vinyl group, a (meth) acrylate group, or a (meth) acryloxy group; A resin having a fluorine group, an oil or a surfactant, but the present invention is not limited thereto.

According to one embodiment of the present invention, the silicon-based or fluorine-based compound is used in an amount of about 0.2 parts by weight or more, or about 0.3 parts by weight or more, or about 0.5 parts by weight, or about 1 part by weight Parts by weight, up to about 10 parts by weight, or up to about 8 parts by weight, or up to about 6 parts by weight. If the content of the silicon-based or fluorine-based compound is too small, the scratch resistance effect may be low. If the content is too large, the strength of the polarizer protective film may be lowered.

According to one embodiment of the present invention, the coating composition may further comprise an oxetane-based compound as a cationic thermosetting binder.

The oxetane-based compound contains at least one oxetane group, and is cured by the cation generated from the cationic thermosetting agent by heat treatment. The kind of the binder is not particularly limited.

The oxetane-based compound can lower the viscosity of the coating composition and can further improve the curing rate.

More specifically, the oxetane-based compound may be, for example, 3-ethyl-3 - [(3-ethyloxetan-3-yl) methoxymethyl] oxetane, 1,4-bis [ 3-yl) methoxy] benzene, 1,3-bis [(3-ethyloxetan-3-yl) Methoxy] benzene, 4,4'-bis [(3-ethyloxetan-3-yl) methoxy] biphenyl, Bis [(3-ethyloxetan-3-yl) methoxy] biphenyl, 3,3 ', 5,5'-tetramethyl-4,4'- 3-yl) methoxy] biphenyl, 2,7-bis [(3-ethyloxetan-3- yl) methoxy] naphthalene, bis {4- [ Methoxy] phenyl} methane, 2,2-bis {4 - [(3-ethyloxetan-3-yl) methane] Ethoxy] phenyl} propane, 3-chloromethyl-3-ethyloxetane etherified product of novolac phenol-formaldehyde resin, 3 (4) Yl) methoxymethyl] -tricyclo [5. 2.1.0 2,6] decane, 2,3-bis [(3-ethyloxetan-3-yl) methoxymethyl] norborane, 1,1,1-tris [ (Methoxymethyl) propane, 1-butoxy-2,2-bis [(3-ethyloxetan-3- yl) methoxymethyl] Ethyl} oxetan-3-yl) methoxy] ethylthio} ethane, bis {[4- Cetan-3-yl) methoxy] -2,2,3,3,4,4,5,5-octafluorohexane.

According to one embodiment of the present invention, there is provided a process for preparing 3-ethyl-3- (hydroxymethyl) oxetane, m-tetramethyl-xylene diisocyanate azelaic chloride, terephthaloyl chloride and 1,3,5- And tricarbonyl trichloride can be used as the compound of the present invention.

When the oxetane-based compound is further included, the content thereof may be about 5 to about 80 parts by weight, and preferably about 10 to about 60 parts by weight based on 100 parts by weight of the cationic thermosetting resin. When the oxetane-based compound is contained in an excessively large amount, the hardness of the coating layer after curing may be lowered. When the content of the oxetane-based compound is too small, the effect of addition of the oxetane-based compound is insignificant.

The coating composition of the present invention is low in viscosity and good in coatability and can be used in a solvent-free type without a solvent. However, it does not exclude the use of an organic solvent, and may contain a small amount of an organic solvent generally used in the art if necessary. At this time, the organic solvent may be used in an amount of about 20 parts by weight or less based on 100 parts by weight of the coating composition for the entire polarizer protective film.

Examples of usable organic solvents include alcohol solvents such as methanol, ethanol, isopropyl alcohol and butanol, alkoxy alcohol solvents such as 2-methoxyethanol, 2-ethoxyethanol and 1-methoxy-2-propanol, , Ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, methyl propyl ketone and cyclohexanone, propylene glycol monopropyl ether, propylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl Ether-based solvents such as ether, diethylene glycol monomethyl ether, diethyl glycol monoethyl ether, diethyl glycol monopropyl ether, diethyl glycol monobutyl ether and diethylene glycol-2-ethylhexyl ether, benzene, toluene, Aromatic solvents such as rhenium, and the like may be used alone or in combination.

Meanwhile, the coating composition of the present invention may further contain additives commonly used in the art such as surfactants, antioxidants, leveling agents, antifouling agents, antistatic agents, antifoaming agents, preservatives, heat stabilizers and the like, As shown in FIG. The content can be varied within a range that does not deteriorate the physical properties of the coating composition of the present invention. Therefore, it may be included in an amount of about 0.1 to about 10 parts by weight based on 100 parts by weight of the total coating composition, have.

In one embodiment of the present application, a substrate film; And a coating layer comprising a coating composition according to an embodiment of the present application provided on one side or both sides of the base film.

The weight average molecular weight of the epoxy compound may be 100 to 5,000 g / mol.

Wherein the epoxy compound is an alicyclic epoxy compound.

In one embodiment of the present application, 55 to 95 parts by weight of the cation-curable epoxy resin, based on 100 parts by weight of the coating composition; 0.3 to 40 parts by weight of the compound; And 0.1 to 10 parts by weight of the cationic initiator.

In one embodiment of the present application, the cationic initiator comprises a sulfonium salt or an iodonium salt.

In one embodiment of the present application, the thickness of the coating layer is 200 nm or more and 5 占 퐉 or less.

In still another embodiment, the thickness of the coating layer may be 250 nm or more and 4 占 퐉 or less, preferably 250 nm or more and 3 占 퐉 or less.

When the stretching process is performed, the thickness of the coating layer is reduced in inverse proportion to the stretching ratio, and thus the thickness of the coating layer means the thickness of the final coating layer after the stretching process.

When the coating layer has the above-mentioned thickness range, it is possible to provide a protective film which is excellent in coating adhesion to a base film and is particularly excellent in coating blasting characteristics and diffusing plate blasting characteristics. As such, the protective film can be manufactured in a thin shape and exhibits sufficient strength. In addition, even a single coating layer can exhibit sufficient hardness and scratch resistance, exhibiting anti-blocking properties by itself, and high workability and productivity in the manufacturing process.

According to an embodiment of the present application, Applying a coating composition according to one embodiment of the present application on at least one side of a substrate film; And a step of stretching the base film coated with the coating composition.

The method of applying the coating composition is not particularly limited as long as it can be used in the technical field to which the present technology belongs. Examples of the coating method include bar coating method, knife coating method, roll coating method, blade coating method, die coating method, micro gravure coating method , A comma coating method, a slot die coating method, a lip coating method, or a solution casting method.

In one embodiment of the present application, the stretching ratio in the step of stretching the base film is 1.05 to 10 times the length in the stretching direction.

In one embodiment of the present application, the stretching temperature in the step of stretching the base film may be 100 占 폚 or more and 180 占 폚 or less, preferably 110 占 폚 or more and 160 占 폚 or less, more preferably 120 占 폚 or more and 140 占 폚 or less .

In the production method according to one embodiment of the present application, the coating composition according to one embodiment of the present application includes a thermosetting agent so that curing can be induced in the stretching process within the range of temperature without a specific thermosetting process, And the curing of the coating composition is simultaneously carried out in the drawing step.

That is, after the stretching process, a thermosetting process or a UV irradiation process is not added, so that the process cost can be further reduced.

In one embodiment of the present application, the method further comprises a step of stretching the base film before the step of applying the coating composition on one side of the base film.

When the base film is uniaxially stretched before application of the coating composition, it is preferable that the stretching direction after the coating is stretched in the direction perpendicular to the stretching direction before coating the coating composition. For example, if the base film is stretched in the MD direction before application of the coating composition, it may be stretched in the width direction (TD) after application of the coating composition.

When the coating composition is stretched before and after coating, the total stretching ratio is at least 1.1 times, or at least 1.2 times, or at least 1.5 times, at least 25 times, or at most 10 times the total stretching area of the substrate film, Fold or less, or 7 times or less. When the stretching ratio is less than 1.1 times, the effect of stretching may not be sufficiently achieved, and when the stretching ratio is more than 25 times, the coating layer may be cracked.

Before the stretching, the coating surface of the coating composition may be planarized and dried to volatilize the solvent contained in the coating composition.

The polarizer protective film of the present invention is used for protecting the polarizer from the outside, and at least one surface of the polarizer , Preferably as a lower protective film of the polarizer.

On the other hand, as the liquid crystal display device becomes larger and slimmer, a sagging phenomenon of the lower polarizer plate occurs, and the lower protective film of the lower polarizer plate comes into contact with the backlight unit, causing scratches.

Accordingly, the polarizer protective film obtained by the production method of the present invention exhibits excellent physical properties such as scratch resistance and hardness due to the stretched coating layer, thereby effectively protecting the lower polarizer, and being applicable to a polarizer for a liquid crystal display device .

The base film is not particularly limited, but may be a polyester, a polyethylene, a cyclic olefin polymer (COP), a cyclic olefin copolymer (COC), a polyacrylate , PAC), polycarbonate (PC), polymethylmethacrylate (PMMA), polyimide (PI), or cellulose.

The thickness of the base film is not particularly limited, but a film having a thickness of about 50 to 1,000 占 퐉, specifically 100 to 500 占 퐉 may be used in consideration of the subsequent stretching process.

The method for forming the base film is not particularly limited, and an unstretched base film can be prepared by a suitable film forming method such as a solution casting method, a melt extrusion method, a calendering method, and a compression molding method.

When the base film is stretched, if the polymer is rearranged in the stretching process and a functional coating layer or the like is further formed on the stretched base film, there is a problem that the adhesion is reduced. Therefore, there is a method of adding a separate process such as forming a primer layer for securing adhesion or adding a functional compound capable of improving adhesion to the coating layer. In this case, a separate process is added in the manufacturing process, There is a problem in that the development of universal primers is difficult due to physical and chemical properties of each film. Further, adding a functional compound to the coating layer may also cause a problem of cost increase and other property deterioration.

Accordingly, the present invention has been made to solve the above problems, and it is possible to provide a polarizer protective film having sufficient scratch resistance and thinness even without a separate primer layer according to an embodiment of the present invention.

According to one embodiment of the present invention, the base film can apply the coating composition on one side thereof in an unstretched state.

In another embodiment, the substrate film may be subjected to uniaxial stretching prior to application of the coating composition.

At this time, the stretching direction is not particularly limited, and it may be stretched in the width direction (TD) direction or the length (MD) direction, and may be uniaxially stretched or biaxially stretched. The stretching ratio can be stretched so as to be 1.1 times or more, 1.2 times or 1.5 times or more, 5 times or less, or 3 times or less based on the length in the stretching direction.

The coating composition for a polarizer protective film according to one embodiment of the present application is applied on at least one side of the unstretched or uniaxially stretched base film.

Generally, in order to form a functional coating layer such as a hard coating layer on a polarizer protective film, a method of applying a coating composition on a base film, drying and curing it is used. However, in the case of the base film, since the polymer is rearranged in the stretching process, there is a problem that the coating layer does not adhere well to the base film. There is a method of forming a primer layer in order to ensure adhesion, however, there is a problem that productivity is lowered due to the addition of a separate step in the manufacturing process, and there is a problem that development of a general purpose primer is difficult.

According to the production method of the present invention, the coating composition is applied onto the base film and simultaneously stretched and cured to form a coating layer, whereby adhesion to the stretched base film is high without requiring a separate primer layer, It is possible to provide a polarizer protective film as much as possible.

On the other hand, when the coating composition is too rigid, there is a problem that the coating layer becomes uneven or the drawing is not performed properly in the drawing process after coating. On the contrary, when the coating composition is flexible and the drawing rate is too high, And scratch resistance can not be ensured.

Therefore, in order to exhibit sufficient scratch resistance after a uniform stretching process and curing, it is important to appropriately adjust the flexibility and strength of the coating composition in addition to the control of the draw ratio of the base film.

Thus, according to the production method of the present invention, it is possible to provide a polarizer protective film that satisfies the above-mentioned requirements by optimizing the composition of the coating composition and the stretching process.

The coating layer may be formed on only one side of the base film, or may be formed on both sides of the base film.

When the coating layer is formed only on one side of the stretched base film, the other side may further include another photocurable coating layer and / or a thermosetting coating layer or other layers, films, or films for imparting functionality have. It is also possible to further form another functional layer on the coating layer.

As such, when the protective film of the present invention includes another layer, film or film or the like on the other surface of the stretched base film, the forming method and the step are not limited. For example, a method of coating the base film before stretching and curing after stretching, a method of coating and curing after stretching the base film, a method of coating a layer, a film, or a film formed separately using an adhesive, Film or film may be laminated on the other surface of the stretched substrate film by various methods known in the art, such as a method of laminating the stretched substrate film to the substrate.

The polarizer protective film of the present invention is obtained by connecting a sample to a vibration generator and superimposing the sample and the diffusion sheet in contact with each other so that the vibration is applied for a predetermined time in a state of applying a load and then checking the surface of the polarizer protective film, Can be evaluated.

Further, the polarizer protective film obtained by the production method of the present invention may have a pencil hardness of H or higher at a load of 500 g.

In one embodiment of the present application, a polarizer; And a polarizer protective film according to an embodiment of the present application on at least one side of the polarizer.

At this time, the polarizer is not particularly limited, and a film made of polyvinyl alcohol (PVA) including a polarizer well-known in the related art, for example, iodine or a dichroic dye, is used.

The polarizer vibrates in various directions and exhibits a characteristic of extracting only light vibrating in one direction from the incident light. This property can be achieved by stretching polyvinyl alcohol (PVA) absorbing iodine with a strong tension. For example, more specifically, there is a method comprising swelling a PVA film by swelling in an aqueous solution, dyeing the swollen PVA film with a dichroic material imparting polarizing properties, stretching the dyed PVA film, ) To align the dichroic dye materials in the stretching direction, and a polarizing step for correcting the color of the PVA film after the stretching step. However, the polarizing plate of the present invention is not limited thereto.

According to an embodiment of the present invention, the polarizer protective film may be attached to both surfaces of the polarizer.

When the polarizer protective film of the present invention is laminated on the polarizer and adhered, it is preferable that the base film is attached to the polarizer.

According to another embodiment of the present invention, the polarizer protective film is provided on only one side of the polarizer, and the general protective film commonly used for protecting the polarizer may be provided on the other side.

At this time, the polarizing plate can be used as a lower polarizing plate of an LCD, and the polarizing plate protective film of the present invention can be positioned at a lower position in a laminated structure in an LCD.

As described above, when the polarizer protective film is laminated on the LCD and the polarizer is laminated on the LCD, the lower protective film of the polarizer is damaged by abutting against the backlight unit provided under the polarizer, thereby preventing the haze from increasing, have.

The polarizer and the polarizer protective film can be bonded by lamination using an adhesive or the like. Usable adhesives are not particularly limited as long as they are known in the art. For example, a water-based adhesive, a one-component or two-component polyvinyl alcohol (PVA) adhesive, a polyurethane adhesive, an epoxy adhesive, a styrene butadiene rubber adhesive (SBR adhesive), a hot melt adhesive, The present invention is not limited to these examples.

When the polarizer protective film of the present invention is laminated on the polarizer and adhered to the polarizer, it is preferable that the stretched coating layer is laminated so as to be attached to the polarizer on the surface on which the stretched coating layer is not formed and the stretched coating layer is positioned outside the polarizer.

The polarizing plate having the polarizer protective film of the present invention is applied to an LCD, but the present invention is not limited thereto and can be used in various fields. For example, mobile communication terminals, smart phones, other mobile devices, display devices, electronic blackboards, outdoor electronic signboards, and various displays. According to an embodiment of the present invention, the polarizing plate may be a TN (Twisted Nematic) or STN (Super Twisted Nematic) liquid crystal polarizing plate, and may be an IPS (In-Plane Switching), a Super-IPS, a Fringe Field Switching Or a polarizing plate for the vertical alignment mode.

In one embodiment of the present application, a liquid crystal cell; An upper polarizer provided on an upper portion of the liquid crystal cell; A lower polarizer disposed on a lower portion of the liquid crystal cell; And a backlight unit provided on a lower portion of the lower polarizer, wherein the lower polarizer comprises a polarizer; And a polarizer protective film according to an embodiment of the present application disposed on one side or both sides of the polarizer.

In one embodiment of the present application, the polarizer protective film is disposed to face the backlight unit.

1 is a diagram showing a liquid crystal display device including a polarizer protective film obtained by the production method of the present invention.

The backlight unit includes a light source that emits light from the back surface of the liquid crystal panel, and the type of the light source is not particularly limited, and a general LCD light source such as CCFL, HCFL, or LED can be used.

Best Mode for Carrying Out the Invention Hereinafter, the function and effect of the present invention will be described in more detail through specific examples of the present invention. It is to be understood, however, that these embodiments are merely illustrative of the invention and are not intended to limit the scope of the invention.

< Example >

Preparation of coating compositions

Table 1 below shows the composition and content of the coating composition according to the present application.

Suzy Cationic curing agent Wax powder Kinds content Kinds content Kinds TYPE content Particle size (D50, ㎛) Production Example 1 S-28 100 SI-B3 0.1 CERAFAK-127N Fischer-Tropsch wax 0.1 3.0 Production Example 2 S-28 100 SI-B3 0.1 CERAFAK-127N Fischer-Tropsch wax 0.5 3.0 Production Example 3 S-28 100 SI-B3 0.1 CERAFAK-127N Fischer-Tropsch wax 1.0 3.0 Production Example 4 S-28 100 SI-B3 0.1 CERAFAK-127N Fischer-Tropsch wax 5.0 3.0 Production Example 5 S-28 100 SI-B3 0.1 CERAFAK-127N Fischer-Tropsch wax 10.0 3.0 Production Example 6 S-28 100 SI-B3 0.1 CERACOL-79 Carnauba wax 1.0 2.0 Production Example 7 S-28 100 SI-B3 0.1 CERACOL-601 Carnauba wax 1.0 2.0 Production Example 8 S-28 100 SI-B3 0.1 CERACOL-609N Carnauba wax 1.0 3.0 Production Example 9 S-28 100 SI-B3 0.1 CERAFLOUR_970 PP Wax 0.2 9.0 Production Example 10 S-28 100 SI-B3 0.1 CERAFLOUR_981 Polytetrafluoroethylenewax 0.2 3.0 Production Example 11 S-28 100 SI-B3 0.1 CERAFLOUR_994 Amide wax 0.2 5.0 Production Example 12 S-28 100 SI-B3 0.1 CERAFLOUR_990 PE wax 0.2 6.0 Production Example 13 S-28 100 SI-B3 0.1 - - - - Production Example 14 S-28 100 SI-B3 0.1 F-553 (DIC) Fluoro system 0.3 - Production Example 15 S-28 100 SI-B3 0.1 TEGO Glide 435 Silicon system 0.3 - Production Example 16 S-28 100 SI-B3 0.1 MX-150 (Soken) Organic particles 0.4 1.5 Production Example 17 S-28 100 CPI-100P 2.0 CERAFAK-127N Fischer-Tropsch wax 1.0 3.0 Production Example 18 S-28 100 - - CERAFAK-127N Fischer-Tropsch wax 1.0 3.0

Polarizer  Manufacture of protective film

Example  One.

The polymethyl methacrylate resin was subjected to a T-die-peeling process under the condition of 250 占 폚 to prepare an undrawn film having a width of 800 mm and a thickness of 200 占 퐉. The unstretched film was stretched 1.8 times in the length (MD) direction at a temperature of 135 캜 to prepare a uniaxially stretched film.

The coating composition of Preparation Example 1 was coated on the uniaxially stretched film by a bar coating method and then stretched 2.5 times in a width direction (TD) direction at a temperature of 135 ° C.

Example  2.

A polarizer protective film was prepared in the same manner as in Example 1, except that the coating composition of Production Example 2 was used in place of the coating composition of Production Example 1.

Example  3.

A polarizer protective film was prepared in the same manner as in Example 1, except that the coating composition of Production Example 3 was used in place of the coating composition of Production Example 1.

Example  4.

A polarizer protective film was prepared in the same manner as in Example 1, except that the coating composition of Production Example 4 was used in place of the coating composition of Production Example 1.

Example  5.

A polarizer protective film was prepared in the same manner as in Example 1, except that the coating composition of Production Example 5 was used in place of the coating composition of Production Example 1.

Example  6.

A polarizer protective film was prepared in the same manner as in Example 1, except that the coating composition of Production Example 6 was used in place of the coating composition of Production Example 1.

Example  7.

A polarizer protective film was prepared in the same manner as in Example 1, except that the coating composition of Production Example 7 was used in place of the coating composition of Production Example 1.

Example  8.

A polarizer protective film was prepared in the same manner as in Example 1, except that the coating composition of Production Example 8 was used in place of the coating composition of Production Example 1.

Example  9.

A polarizer protective film was prepared in the same manner as in Example 1, except that the coating composition of Production Example 9 was used in place of the coating composition of Production Example 1.

Example  10.

A polarizer protective film was prepared in the same manner as in Example 1, except that the coating composition of Production Example 10 was used in place of the coating composition of Production Example 1.

Example  11.

A polarizer protective film was prepared in the same manner as in Example 1, except that the coating composition of Production Example 11 was used in place of the coating composition of Production Example 1.

Example  12.

A polarizer protective film was prepared in the same manner as in Example 1, except that the coating composition of Production Example 12 was used in place of the coating composition of Production Example 1.

Comparative Example  One.

A polarizer protective film was prepared in the same manner as in Example 1, except that the coating composition of Production Example 13 was used in place of the coating composition of Production Example 1.

Comparative Example  2.

A polarizer protective film was prepared in the same manner as in Example 1, except that the coating composition of Production Example 14 was used in place of the coating composition of Production Example 1.

Comparative Example  3.

A polarizer protective film was prepared in the same manner as in Example 1, except that the coating composition of Production Example 15 was used in place of the coating composition of Production Example 1.

Comparative Example  4.

A polarizer protective film was prepared in the same manner as in Example 1, except that the coating composition of Production Example 16 was used in place of the coating composition of Production Example 1.

Comparative Example  5.

The polymethyl methacrylate resin was subjected to a T-die-peeling process under the condition of 250 占 폚 to prepare an undrawn film having a width of 800 mm and a thickness of 200 占 퐉. The unstretched film was stretched 1.8 times in the length (MD) direction at a temperature of 135 캜 to prepare a uniaxially stretched film.

The coating composition of Production Example 17 was coated on the uniaxially stretched film by a bar coating method and then stretched 2.5 times in a width direction (TD) direction at a temperature of 135 ° C. The polarizer protective film on which a protective film having a thickness of 2 탆 was formed was prepared by irradiating ultraviolet rays thereto.

Comparative Example  6.

A polarizer protective film was prepared in the same manner as in Example 1 except that the coating composition of Production Example 18 was used in place of the coating composition of Production Example 1.

< Experimental Example  >

<Measurement method>

The properties of the polarizer protective film of the examples were measured by the following methods.

1) Breaking characteristics

A coating layer of the polarizer protective film of the present invention and another sheet having a relief pattern (for example, a diffusion sheet) were superimposed on a sample holder (50 mm x 50 mm) to which a vibration generator was connected. The degree of scratch and scratches on the surface of the coating layer of the polarizer protective film of the present invention and the surface of the other sheet was almost the same as that of the protective film of the present invention even after the application of the applied vibration intensity of 2.8 Grms and the frequency of 20-60 Hz for 240 seconds .

In case of less than 4 levels, the particles of the surface of the coating layer are scraped off and the optical characteristics such as transmittance are partially impaired and the entire panel may become defective. In addition, a strong scratch on the opposite diffusion sheet may cause a failure of the entire panel if the optical characteristics of the diffusion sheet on the opposite side of the coating layer are inhibited by a similar concept.

2) Pencil Hardness

Pencil hardness was measured using a pencil hardness tester (hardness tester, manufacturer: Chungbuk Tech) under a load of 500 g. A standard pencil (Mitsubishi) was changed from 6B to 9H according to ASTM 3363-74, and the surface of the drawn coating layer was scratched by keeping the angle of 45 degrees. Each experimental value was described as a mean value excluding the maximum value and the minimum value after 5 measurements.

In the case of pencil hardness, it is preferable that the hardness standard of the protective film used for the panel is not less than HB and stably exceeds H.

3) Friction coefficient (slip property)

The dynamic / static friction coefficient was measured according to ASTM D1894 using Thwing-Albert's FP-2260. The measurement conditions were a temperature of 25 ° C HR 50%, a length of the lower specimen of 250 mm x 100 mm, a length of the upper specimen of 60 mm x 60 mm, and a measurement of 5 times at a rate of 180 mm / min. Respectively.

In the case of the coefficient of friction, it is an index indicating the slip part and is linked with the breaking property. If the friction coefficient is too low, a problem of winding may occur due to the breaking property.

4) Haze (%)

The average value was measured three times according to JIS K7316 using HM-150 of a murakami color research laboratory.

The results of the physical properties of the polarizer protective films of Examples and Comparative Examples of the present application are shown in Table 2 below.

Shattering Characteristics Pencil hardness Coefficient of friction Haze (%) silence dynamic Example 1 4 2H 0.09 0.49 0.2 Example 2 5 2H 0.03 0.46 0.4 Example 3 5 2H 0.05 0.42 0.5 Example 4 5 2H 0.06 0.24 0.7 Example 5 5 (weak scratch on the contrary) 2H 0.05 0.21 0.8 Example 6 5 2H 0.03 0.47 0.4 Example 7 5 2H 0.05 0.42 0.4 Example 8 5 2H 0.07 0.49 0.2 Example 9 5 (weak scratch on the contrary) 2H 0.09 0.35 1.1 Example 10 5 2H 0.06 0.37 0.3 Example 11 5 2H 0.05 0.40 0.8 Example 12 5 2H 0.10 0.44 0.9 Comparative Example 1 One H Impossible Impossible 0.1 Comparative Example 2 3 H 0.67 0.61 0.2 Comparative Example 3 2 H 1.08 0.60 0.2 Comparative Example 4 4 (strong scratch on opposite side) 2H 0.12 0.27 2.2 Comparative Example 5 5 2H 0.04 0.40 0.5 Comparative Example 6 - - - - -

As can be seen from Table 2, the polarizer protective film according to one embodiment of the present application is used as a protective film of the lower polarizer plate, and thus the polarizer protective film is in contact with the diffusion sheet on the surface of the backlight unit due to deflection of the lower polarizer plate, It is possible to exhibit excellent optical properties by preventing problems that may cause defective devices.

Particularly, Comparative Example 5 in Table 2 is a case where CPI-100P (Diphenyl [(phenylthio) phenyl] sulfonium hexafluorophosphate (1-)) is used as a cationic curing agent in the coating composition according to Production Example 17, However, since the UV irradiation process must be added after the drawing process, applying the embodiments 1 to 12 according to one embodiment of the present application can have a beneficial effect on the process cost and time.

Also, in the case of Comparative Example 6, it was confirmed that the coating composition did not harden in the stretching process when the coating composition did not contain a thermosetting agent.

In the case of using the organic particles of Comparative Example 4, a strong scratch was caused on the opposite surface and the haze was increased. In Examples 1 to 12 using the wax powder according to one embodiment of the present application, a maximum of 1.1% I have.

10: Upper polarizer
20: liquid crystal cell
30: Lower polarizer plate
34: polarizer protective film
40: Backlight unit

Claims (18)

Cationic thermosetting resin;
Wax powder; And
Cationic thermosetting agents;
&Lt; / RTI &gt; The method according to claim 1,
Wherein the cationic thermosetting resin comprises an epoxy compound. The method of claim 2,
Wherein the weight average molecular weight of the epoxy compound is 100 to 5,000 g / mol. The method of claim 2,
Wherein the epoxy compound is an alicyclic epoxy compound. The coating composition of claim 1, wherein the coating composition comprises
Based on 100 parts by weight of the cationic thermosetting resin
0.05 to 30 parts by weight of the wax powder; And
And 0.01 to 10 parts by weight of the cationic thermosetting agent. The method according to claim 1,
Wherein the cationic thermosetting agent comprises a sulfonium salt or an iodonium salt. The method according to claim 1,
Wherein the wax powder has a particle size of 1 占 퐉 or more and 50 占 퐉 or less based on D50. Preparing a base film;
Applying the coating composition of any one of claims 1 to 7 on at least one side of the substrate film; And
And stretching the base film coated with the coating composition. The method of claim 8,
Wherein the stretching ratio in the step of stretching the base film is 1.05 to 10 times the length in the stretching direction. The method of claim 8,
Wherein the stretching temperature in the step of stretching the substrate film is 110 占 폚 to 160 占 폚. The method of claim 8,
Further comprising the step of stretching the base film before the step of applying the coating composition on one side of the base film. A base film; And
A coating layer comprising the coating composition of any one of claims 1 to 7 provided on one side or both sides of the base film;
/ RTI &gt; The method of claim 12,
Wherein the thickness of the coating layer is 200 nm or more and 5 占 퐉 or less. The method of claim 12,
Wherein the thickness of the base film is not less than 20 占 퐉 and not more than 200 占 퐉. The method of claim 12,
The base film may be formed of a material selected from the group consisting of polyester, polyethylene, cyclic olefin polymer (COP), cyclic olefin copolymer (COC), polyacrylate (PAC), poly At least one selected from the group consisting of polycarbonate (PC), polymethylmethacrylate (PMMA), polyimide (PI), polynorbornene (PNB) and cellulose Polarizer protective film. A polarizer; And
And a polarizer protective film according to claim 12 on at least one side of the polarizer. A liquid crystal cell;
An upper polarizer provided on an upper portion of the liquid crystal cell;
A lower polarizer disposed on a lower portion of the liquid crystal cell; And
And a backlight unit provided on a lower portion of the lower polarizer plate,
Wherein the lower polarizer comprises a polarizer; And a polarizer protective film of claim 12 disposed on one or both sides of the polarizer. 18. The method of claim 17,
And the polarizer protective film is disposed to face the backlight unit.

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