KR101600582B1 - Resin composition for polarizer protecting film - Google Patents

Abstract

The present invention relates to a resin composition for a polarizer protective film, and more particularly to a resin composition capable of forming a polarizer protective film exhibiting high hardness and excellent properties. According to the resin composition of the present invention, it is possible to form a protective film which exhibits high hardness, scratch resistance and high transparency and which does not generate curling or cracking due to excellent workability. Such a protective film can be applied to various display devices .

Description

[0001] Resin composition for polarizer protective film [0002]

The present invention relates to a resin composition for a polarizer protective film. More particularly, the present invention relates to a resin composition capable of producing a polarizer protective film exhibiting excellent physical and optical properties.

Liquid crystal displays (LCDs) are one of the most widely used flat panel displays. In general, a liquid crystal display has a structure in which a liquid crystal layer is sealed between a TFT (Thin Film Transistor) array substrate and a color filter substrate. When an electric field is applied to the electrodes existing on the array substrate and the color filter substrate, the arrangement of the liquid crystal molecules in the liquid crystal layer sealed therebetween is changed, and images are displayed using the liquid crystal molecules.

On the other hand, a polarizing plate is provided outside the array substrate and the color filter substrate. The polarizing plate can control the polarization by selectively transmitting light in a specific direction among light incident from the backlight and light passing through the liquid crystal layer.

The polarizer generally has a structure in which a polarizer capable of polarizing light in a specific direction is adhered to a protective film for supporting and protecting the polarizer.

As the protective film, a film made of triacetylcellulose (TAC) is widely used. In addition, a protective film for coating a hard coating layer to achieve a film having properties of hardness and abrasion resistance has been proposed.

On the other hand, in recent years, the use of liquid crystal devices has been widespread and used in various fields of devices, and attention has been paid to the improvement of the hardness and thinness of the polarizing plate.

With respect to this necessity, Japanese Unexamined Patent Application Publication No. 2005-010329 and the like have proposed a polarizing plate in which a TAC film is omitted and a protective layer is formed using a photopolymerizable compound on the surface of a polarizer. However, there is still a demand for a polarizing plate which has sufficient hardness, exhibits a low thickness for thinning and exhibits sufficient flexibility to be suitable for a mass production process.

In order to solve the above problems, the present invention provides a resin composition capable of forming a film for protecting a polarizer, which exhibits high hardness and high transparency, can be thinned, exhibits excellent flexibility at the same time and does not generate curls or cracks .

In order to solve the above problems, the present invention provides a resin composition comprising a polyfunctional acrylate monomer, an acrylate oligomer having an elongation of 5 to 200%, and a binder containing an acrylate-based elastic polymer and a photoinitiator .

According to the resin composition of the present invention, it is possible to form a protective film which exhibits high hardness, scratch resistance and high transparency and does not generate curls or cracks due to excellent workability. Such a protective film can be applied to various display devices , TAC film without a separate coating to make it thin. In particular, since it does not contain a stretched film, the retardation value is substantially as low as zero, so that it can be used not only for a polarizer protective film but also for various devices requiring such a low retardation value, without limitations in application.

In addition, it exhibits excellent workability and flexibility, and is applicable to a large area or curved surface display.

The resin composition of the present invention comprises a polyfunctional acrylate-based monomer, an acrylate-based oligomer having an elongation of 5 to 200%, and a binder containing an acrylate-based elastic polymer, and a photoinitiator.

In the present invention, the terms first, second, etc. are used to describe various components, and the terms are used only for the purpose of distinguishing one component from another.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but on the contrary, is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

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

In the specification of the present invention, acrylate eggs mean not only acrylates but also methacrylates, or derivatives having substituents introduced into acrylate or methacrylate.

The resin composition according to the present invention comprises a polyfunctional acrylate-based monomer, an acrylate-based oligomer having an elongation of 5 to 200%, a binder containing an acrylate-based elastic polymer, and a photoinitiator. The resin composition of the present invention can be used for forming a polarizer protective film.

The polarizer protective film is used to protect the polarizer from the outside.

Polarizer protective films generally used include polyester such as polyethylene terephthalate (PET), cyclic olefin copolymer (COC), polyacrylate (PAC), polycarbonate polycarbonate (PC), polyethylene (PE), polymethylmethacrylate (PMMA), polyetheretherketone (PEEK), polyethylene naphthalate (PEN), polyetherimide , Polyimide (PI), triacetylcellulose (TAC), and the like.

Of these materials, triacetylcellulose (TAC) films have been widely used because of their excellent optical properties. However, when the TAC film is used alone, the surface hardness is weak and it is vulnerable to humidity, and it is necessary to add a functional coating layer such as a hard coating. However, when the functional coating layer is further included, the entire thickness of the protective film is increased, which may not meet the recent requirement for thinning, and curl or cracks may occur in the film due to the additional coating.

Accordingly, the present invention provides a resin composition for forming a protective film having a low thickness so as to be compatible with a sufficient hardness and thinning tendency without replacing the TAC film which is commonly used, and which does not include a separate coating layer. In addition, the protective film formed using the resin composition of the present invention exhibits excellent optical characteristics required for a polarizer protective film and can exhibit excellent flexibility for easy production, processing, storage and transportation.

Further, since the stretched film is not included, the retardation value is so low as to be substantially zero that it can be used not only for the polarizer protective film but also for various devices requiring such a low retardation value, without limitations in application.

In addition, it exhibits excellent workability and flexibility, and is applicable to large area or curved surface displays.

The resin composition of the present invention comprises a polyfunctional acrylate monomer, an acrylate oligomer having an elongation of 5 to 200%, and a binder containing an acrylate-based elastic polymer, and a photoinitiator.

The polyfunctional acrylate-based monomer includes two or more acrylate-based functional groups and has a molecular weight of less than 1,000 g / mol. More specifically, there can be mentioned, for example, hexanediol diacrylate (HDDA), tripropylene glycol diacrylate (TPGDA), ethylene glycol diacrylate (EGDA), trimethylolpropane triacrylate (TMPTA), trimethylolpropane ethoxy tri Acrylate (TMPEOTA), glycerin propoxylated triacrylate (GPTA), pentaerythritol tetraacrylate (PETA), dipentaerythritol hexaacrylate (DPHA) and the like. But is not limited thereto. The polyfunctional acrylate-based monomer is crosslinked with an acrylate-based oligomer and an acrylate-based elastic polymer to impart a constant pencil strength and abrasion resistance to the protective film.

The polyfunctional acrylate monomers may be used alone or in combination of two or more.

According to one embodiment of the present invention, when the total weight of the binder is 100 parts by weight, the polyfunctional acrylate monomer may be included in the range of about 20 to about 70 parts by weight, or about 40 to about 60 parts by weight can do. By incorporating the polyfunctional acrylate monomer in the above range, a protective film excellent in both hardness and flexibility can be formed. When the content of the polyfunctional acrylate monomer is less than 20 parts by weight, the crosslinking density is lowered and the mechanical properties of the coating film such as pencil hardness and scratch resistance may be deteriorated. When the content of the polyfunctional acrylate monomer is more than 70 parts by weight, .

The acrylate oligomer is an acrylate having an elongation of from about 5 to about 200%, or from about 5 to about 100%, or from about 10 to about 50%, as measured by ASTM D638, Or more oligomers. When the elongation percentage of the acrylate-based elastic polymer is in the above range, excellent flexibility and elasticity can be exhibited without deteriorating the mechanical properties.

According to one embodiment of the present invention, the weight average molecular weight of the acrylate oligomer ranges from about 1,000 to about 10,000 g / mol, or from about 1,000 to about 5,000 g / mol, or from about 1,000 to about 3,000 g / mol Lt; / RTI >

The acrylate oligomer is excellent in flexibility and elasticity, and can give sufficient flexibility to a protective film produced using the resin composition containing the acrylate oligomer.

According to an embodiment of the present invention, the acrylate oligomer may be an acrylate oligomer modified with at least one of ethylene oxide, propylene oxide, and caprolactone. When the modified acrylate oligomer is used, flexibility is further imparted to the acrylate oligomer due to modification, so that the curling property and flexibility of the protective film can be increased.

The acrylate oligomers may be used alone or in combination of two or more.

According to an embodiment of the present invention, when the total weight of the binder is 100 parts by weight, the acrylate oligomer may be included in about 20 to about 70 parts by weight, or about 20 to about 50 parts by weight have. When the content of the acrylate oligomer is less than 20 parts by weight, the coating film may not have sufficient flexibility. When the amount of the acrylate oligomer is more than 70 parts by weight, the mechanical properties may be insufficient.

According to the resin composition of the present invention, it is preferable to use a polyfunctional acrylate-based monomer as the binder component, an acrylate-based oligomer having an elongation of 5 to 200%, and an acrylate-based elastic polymer, The cured resin obtained by polymerization of the pentaerythritol oligomer and the acrylate-based elastic polymer together can form a thin protective film without deteriorating optical properties. The protective film thus formed is excellent in surface hardness and scratch resistance without a separate functional coating layer such as a hard coating. In addition, excellent flexibility and flexibility can be secured. Since it contains a cured resin layer that is not a stretched film, the retardation value is substantially as low as zero and can be used for various display devices requiring a low retardation value as well as a polarizer protective film without any limitations in its application.

The resin composition of the present invention comprises an acrylate-based elastic polymer.

The acrylate-based elastic polymer is excellent in flexibility and elasticity and can form a crosslinked copolymer structure by cross-linking with the polyfunctional acrylate-based monomer and the acrylate-based oligomer including an acrylate functional group. Therefore, the protective film formed by using the resin composition containing the same can ensure high elasticity or flexibility while securing mechanical properties, and can minimize the occurrence of curl or crack.

According to one embodiment of the present invention, the acrylate-based elastic polymer has an elongation of from about 5 to about 200%, or from about 5 to about 100%, or from about 10 to about 50%, as measured by ASTM D638 . When the elongation percentage of the acrylate-based elastic polymer is in the above range, excellent flexibility and elasticity can be exhibited without deteriorating mechanical properties.

According to one embodiment of the present invention, the acrylate-based elastic polymer has a weight average molecular weight ranging from about 100,000 to about 800,000 g / mol, or about 150,000 to about 700,000 g / mol, or about 180,000 to about 650,000 g / mol Lt; / RTI > If the weight average molecular weight of the acrylate-based elastic polymer is too small, the flexibility and elasticity of the protective film produced using the acrylate elastic polymer may be insufficient. If the weight average molecular weight is too large, compatibility with other materials may deteriorate, It may be difficult to obtain a composition, and from this viewpoint, it may be preferable to have a weight average molecular weight in the above-mentioned range.

An example of the acrylate-based elastic polymer is polyrotaxane.

In general, poly-rotaxane is a compound in which a dumbbell shaped molecule and a macrocycle are structurally embedded. Means that the dumbbell-shaped molecule comprises a constant linear molecule and a blocking group disposed at both ends of the linear molecule, wherein the linear molecule penetrates the interior of the cyclic compound, and wherein the cyclic compound comprises the linear molecule So that it can move and is prevented from being released by the blocker.

According to an embodiment of the present invention, Wherein the polyrotaxane is a cyclic compound having a lactone compound bound to an acrylate compound at the terminal thereof; Linear molecules passing through the cyclic compound; And a blocking group disposed at both ends of the linear molecule to prevent the elimination of the cyclic compound.

The cyclic compound can be used without any limitations as far as it has a size enough to penetrate or surround the linear molecule. The cyclic compound may be a compound having a hydroxyl group, an amino group, a carboxyl group, a thiol group or an aldehyde group Functional groups. Specific examples of such cyclic compounds include? -Cyclodextrin,? -Cyclodextrin,? -Cyclodextrin, and mixtures thereof.

In addition, as the linear molecule, a compound having a straight chain form can be used without any limitation if it has a molecular weight of a certain level or higher, but a polyalkylene compound or a polycaprolactone group can be used. Specifically, a polyoxyalkylene compound containing an oxyalkylene repeating unit having 1 to 8 carbon atoms or a polycaprolactone group having a lactone repeating unit having 3 to 10 carbon atoms can be used.

And, such linear molecules may have a weight average molecular weight of about 1,000 to about 50,000 g / mol. If the weight average molecular weight of the linear molecule is too small, the protective film produced using the linear molecule may have insufficient mechanical properties or self-healing ability. If the weight average molecular weight is too large, The uniformity of properties and materials may be greatly reduced.

On the other hand, the blocking group can be appropriately controlled in accordance with the properties of the polyrotaxane to be produced, and includes, for example, one kind selected from the group consisting of a dinitrophenyl group, a cyclodextrin group, an adamantane group, a trityl group, Two or more species can be used.

Another example of the acrylate-based elastic polymer is a urethane-based acrylate polymer. The urethane-based acrylate polymer has a form in which urethane-based acrylate oligomers are side-linked to the main chain of the acrylic polymer.

According to an embodiment of the present invention, when the total weight of the binder is 100 parts by weight, the acrylate-based elastic polymer may be included in about 1 to about 50 parts by weight, or about 1 to about 30 parts by weight . By incorporating the above-mentioned acrylate-based elastic polymer within the above range, a protective film excellent in both hardness and flexibility can be formed.

The above-mentioned polyfunctional acrylate-based monomer, the acrylate-based oligomer having an elongation of 5 to 200%, and the binder containing the acrylate-based elastic polymer can be polymerized with each other by ultraviolet rays to form a cured resin. The resin composition according to the present invention includes the acrylate-based elastic polymer together with the polyfunctional acrylate-based monomer and the acrylate-based oligomer described above, and the protective film formed by curing the acrylate-based elastic polymer exhibits high hardness and flexibility have. Accordingly, the polarizer protective layer can function as a polarizer protective layer without a separate functional coating layer, and at the same time, can function as a hard coating layer and can be applied as a multi-functional polarizer protective film.

The resin composition of the present invention comprises a photoinitiator.

Examples of the photoinitiator include 1-hydroxy-cyclohexyl-phenylketone, 2-hydroxy-2-methyl-1-phenyl- 2-benzoyl-2- (dimethylamino) -1- [4- (4-methoxyphenyl) -2-methyl-1-propanone, methylbenzoylformate, -Morpholin yl) phenyl] -1-butanone, 2-methyl-1- [4- (methylcio) , 6-trimethylbenzoyl) -phosphine oxide, or bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, but the present invention is not limited thereto. Products currently on the market include Irgacure 184, Irgacure 500, Irgacure 651, Irgacure 369, Irgacure 907, Darocur 1173, Darocur MBF, Irgacure 819, Darocur TPO, Irgacure 907 and Esacure KIP 100F. These photoinitiators may be used alone or in combination of two or more.

According to an embodiment of the present invention, when the total weight of the binder is 100 parts by weight, the photoinitiator may be included in about 1 to about 10 parts by weight, or about 1 to about 8 parts by weight.

The resin composition of the present invention can be used in the form of a solvent-free solvent when the blending of each component is uniform and the viscosity is appropriate and there is no problem in the coating process.

Meanwhile, the resin composition of the present invention may further include an organic solvent for uniform mixing and application of the respective components.

Examples of the organic solvent 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 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, Ether solvents such as diethylene glycol monomethyl ether, diethyl glycol monoethyl ether, diethyl glycol monopropyl ether, diethyl glycol monobutyl ether and diethylene glycol-2-ethylhexyl ether, benzene, toluene, The same aromatic solvent may be used alone or in combination.

According to an embodiment of the present invention, the content of the organic solvent may be variously adjusted within a range not lowering the physical properties of the resin composition, so that the content is not particularly limited.

According to one embodiment of the present invention, the resin composition of the present invention may further comprise inorganic fine particles. The inorganic fine particles may be contained in the resin composition in a form dispersed in the polyfunctional acrylate-based monomer.

The inorganic microfine particle may be an inorganic microfine particle having a nanoscale particle size, for example, a particle size of about 100 nm or less, or about 10 to about 100 nm, or about 10 to about 50 nm. The inorganic fine particles may include, for example, silica fine particles, aluminum oxide particles, titanium oxide particles, or zinc oxide particles.

By including the inorganic fine particles, the hardness of the protective film can be further improved.

According to an embodiment of the present invention, when the resin composition further comprises inorganic fine particles, the inorganic fine particles may be contained in an amount of about 1 to about 50 parts by weight when the total weight of the binder is 100 parts by weight, About 1 to about 40 parts by weight. By incorporating the inorganic fine particles in the above range, a protective film excellent in both hardness and flexibility can be formed.

On the other hand, the resin composition of the present invention may contain the above-mentioned polyfunctional acrylate-based monomer, an acrylate oligomer having an elongation of 5 to 200%, an acrylate-based elastic polymer, an inorganic fine particle, a photoinitiator, A surfactant, a yellowing inhibitor, a leveling agent, an antifouling agent, and the like, which are commonly used in the technical field of the present invention. The content thereof is not particularly limited as it can be variously adjusted within a range that does not deteriorate the physical properties of the protective film of the present invention.

According to one embodiment of the present invention, for example, the resin composition may contain a surfactant as an additive, and the surfactant may be a fluorinated acrylate, a fluorinated surfactant or a silicone surfactant having 1 to 2 functionalities. At this time, the surfactant may be dispersed or crosslinked in the cured resin.

Further, the additive may include a yellowing inhibitor, and examples of the yellowing inhibitor include a benzophenone-based compound or a benzotriazole-based compound.

As described above, the polyfunctional acrylate-based monomer, the acrylate oligomer having an elongation of 5 to 200%, and the binder containing the acrylate-based elastic polymer, the photoinitiator, and optionally the organic solvent, the inorganic fine particles, The polarizer protective film can be formed.

According to an embodiment of the present invention, the polarizer protective film may be manufactured by the following method.

First, the resin composition of the present invention containing the above-mentioned components is applied on a release film.

The release film may be used without limitation as long as it is commonly used in the technical field to which the present invention belongs. According to an embodiment of the present invention, the release film may be a polyolefin film such as a polyester film, a polyethylene film, a polyethylene terephthalate film, a polypropylene film, or a Teflon film. Preferably, Resin, melamine resin, urea resin, or the like. The thickness of the release film is not particularly limited, but a release film having a thickness of about 20 to about 200 mu m can be mainly used.

The release film may be peeled off after the protective film is attached to the polarizer after curing the resin composition. Or may be removed after attaching to the polarizer to favor transport and storage.

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

Next, a protection film can be formed by irradiating the applied resin composition with external light to perform photo-curing reaction. Before applying the ultraviolet rays, the application surface of the resin composition may be planarized and the solvent contained in the composition may be dried to volatilize the resin.

The dose of the ultraviolet ray may be about 20 to about 600 mJ / cm < ² >. The light source for ultraviolet irradiation is not particularly limited as long as it can be used in the technical field to which the present technology belongs. For example, a high pressure mercury lamp, a metal halide lamp, a black light fluorescent lamp and the like can be used.

After the resin composition is completely cured, a polarizer protective film formed into a single layer without a base film such as TAC or a separate coating layer can be obtained. In addition, the polarizer protective film does not contain a triacetyl cellulose (TAC) component.

According to the present invention, a protective film is applied directly on a polarizer and cured to form a protective film on a separate release film without being formed directly on the polarizer, thereby curing the protective film, thereby preventing curling or cracking, Can be formed. In addition, it is possible to provide a polarizer protective film of high hardness without lowering the physical properties required for a polarizer protective film such as transmittance and retardation.

The protective film formed using the resin composition of the present invention exhibits high hardness, flexibility, scratch resistance, high transparency, etc., and can be used as a single layer film for protecting polarizers and can be usefully used in various display devices.

According to one embodiment of the present invention, the protective film has a thickness of at least about 10 microns, such as from about 10 to about 200 microns, or from about 10 to about 100 microns, or from about 10 to about 50 microns, About 40 占 퐉, or about 10 to about 30 占 퐉. According to the present invention, it is possible to provide a protective film having a thickness as described above, which is thinner than a film including a separate coating layer on a substrate such as TAC and has a high hardness without causing curling or cracking.

The polarizer and the protective film may be adhered using an adhesive for a polarizer which has transparency and can maintain the polarizing property of the polarizer. Usable adhesives are not particularly limited as long as they are known in the art.

The protective film formed using the resin composition of the present invention may be provided on at least one surface of the polarizer.

More specifically, the polarizing plate can be produced by the following method.

First, the polymer composition of the present invention includes a polyfunctional acrylate monomer, an acrylate oligomer having an elongation of 5 to 200%, and a binder containing an acrylate based elastic polymer, a photoinitiator, an organic solvent, an inorganic microfine particle, The resin composition of the present invention is coated on a release film and a photo-curing reaction is performed to form a protective film. A more detailed description of the step of forming the protective film is as described above.

After the resin composition is completely cured, a polarizer protective film formed into a single layer without a base film such as TAC or a separate coating layer can be obtained.

Next, the polarizing plate can be obtained by laminating the formed protective film with a polarizer using an adhesive and then bonding.

In the present invention, the protective film may be included on only one side of the polarizer or on both sides of the polarizer.

According to an embodiment of the present invention, the protective film may be attached to both surfaces of the polarizer. According to another embodiment of the present invention, the protective film may be attached to only one side of the polarizer and another general film such as TAC may be attached to the other side. At this time, the protective film formed using the resin composition can be positioned at the outermost face facing the user. As described above, the protective film formed using the resin composition of the present invention exhibits high hardness, scratch resistance, and optical properties suitable for the outermost layer.

The protective film formed using the resin composition of the present invention exhibits properties superior enough to replace the TAC film, and therefore, the polarizing plate comprising the polarizing plate can have excellent pencil hardness, curling property, flexibility and optical characteristics.

For example, according to one embodiment of the present invention, when a protective film formed using the resin composition of the present invention or a polarizing plate having the protective film is placed on a plane after being exposed at room temperature for 24 hours, The average value of the distance that a corner or one side is spaced from the plane may be about 3 mm or less, or about 2 mm or less, or about 1 mm or less.

The protective film formed using the resin composition of the present invention or the polarizing plate having the protective film may have a pencil hardness of not less than 1H, or not less than 2H, or not less than 3H under a load of 500 g.

The protective film formed using the resin composition of the present invention may have a unit transmittance of 40% or more, or 42% or more.

Further, the protective film formed using the resin composition of the present invention may not crack when it is wrapped around a cylindrical mandrel having a diameter of 15 mm, 12 mm, or 5 mm.

In addition, the protective film formed using the resin composition of the present invention may exhibit a retardation value in the range of 0 to 1 nm, or 0 to 0.6 nm, or 0 to 0.5 nm.

The polarizing plate having the protective film formed using the resin composition of the present invention 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.

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 >

Polyrotaxane  Produce

Manufacturing example  One

After the addition of 50 g of polyrotase polymer grafted with caprolactone [A1000, Advanced Soft Material INC] to the reactor, 4.53 g of Karenz-AOI [2-acryloylethyl isocyanate, Showa Denko KK], Dibutyltin dilaurate [DBTDL, Merck ], 110 mg of hydroquinone monomethylene ether, and 315 g of methyl ethyl ketone were added and reacted at 70 ° C for 5 hours to obtain a polyrotase containing cyclodextrin having a polycaprolactone group bonded at its terminal with an acrylate compound introduced therein as a cyclic compound &Lt; / RTI &gt;

The weight average molecular weight of the resulting polyrotasane polymer was 600,000 g / mol, and the elongation as measured by ASTM D638 was 20%.

Production of protective film

Example  One

50 g of trimethylolpropane triacrylate (TMPTA), 30 g of DPCA120 (Nippon Kayaku, caprolactone denatured 6-functional group acrylate, 12% elongation measured by ASTM D638, Mw 1,950), PU3400 (trade name, ethylene oxide modified functional group acrylate, 10 g of polyrotasene of Production Example 1, 6 g of a photoinitiator (trade name: Darocur TPO), 3 g of UV absorber (trade name: Chimassorb 81) and 10 g of MEK were mixed to prepare a coating solution PET release film was bar coated. This was dried at 60 DEG C for 2 minutes, and then black UV was irradiated in a nitrogen atmosphere to obtain a protective film having a thickness of 25 mu m.

Example  2

15 g of TMPTA, 30 g of DPCA120, 15 g of TA604AU (ethylene oxide-modified trifunctional acrylate, ethylene oxide modified functional group acrylate, 49% elongation measured by ASTM D638, Mw 2,300), 5 g of polyrotase in Production Example 1, 6 g of photoinitiator (trade name Darocur TPO) , 3 g of UV absorber (trade name: Chimassorb 81) and 10 g of MEK were mixed to prepare a coating liquid and bar-coated on a PET release film. This was dried at 60 DEG C for 2 minutes, and then black UV was irradiated in a nitrogen atmosphere to obtain a protective film having a thickness of 25 mu m.

Example  3

20 g of TMPTA, 10 g of PU3400, 20 g of TA604AU, 20 g of 8BR-500 (Daesung Chemical Co., 7% elongation measured by ASTM D638, Mw 180,000), 6 g of a photoinitiator (trade name Darocur TPO), 3 g of UV absorber (Chimassorb 81) The coating solution was prepared by mixing and bar-coated on PET release film. This was dried at 60 DEG C for 2 minutes, and then black UV was irradiated in a nitrogen atmosphere to obtain a protective film having a thickness of 25 mu m.

Comparative Example  One

50 g of TMPTA, 50 g of EB1290 (SK Cytec, 6 functional group urethane acrylate, 0% elongation measured with ASTM D638, Mw 1,000), 6 g of a photoinitiator (trade name: Darocur TPO), 3 g of UV absorber (trade name: Chimassorb 81) A coating solution was prepared and bar-coated on a 40 탆 thick TAC film. This was dried at 60 DEG C for 2 minutes, and black UV was irradiated in a nitrogen atmosphere to obtain a protective film containing a coating layer having a thickness of 6 mu m on the TAC film.

Production of Polarizer

Example  4

The protective film prepared in Example 1 was laminated and laminated with a PVA film so that the thickness of the adhesive layer was approximately 1 占 퐉 using an acrylic adhesive, and the PET release film was peeled off.

On the other side of the PVA, a polarizing plate was prepared by adhering TAC with a thickness of 40 탆 in the same manner.

Example  5

A polarizing plate was prepared in the same manner as in Example 4, except that a protective film of Example 2 was attached to one surface of the PVA film and a TAC film of 40 m thickness was attached to the other surface of the PVA film.

Example  6

A polarizing plate was prepared in the same manner as in Example 4, except that the protective film of Example 3 was attached to one side of the PVA film and the TAC film was attached to the other side of the PVA film.

Comparative Example  2

A polarizing plate was prepared in the same manner as in Example 4, except that a TAC film having a coating layer of Comparative Example 1 was attached to one side of the PVA film and a TAC film having a thickness of 40 m was attached to the other side thereof.

Comparative Example  3

On both sides of the PVA film, a TAC film having a thickness of 40 占 퐉 was laminated with a PVA film so that the thickness of the adhesive layer was approximately 1 占 퐉, using an acrylic adhesive, and a polarizing plate was produced.

< Experimental Example >

<Measurement method>

1) Thickness

And measured using a digital micrometer.

2) Transmittance

The transmittance and haze were measured using a haze meter (HM 150).

3) Phase difference

The retardation value in the plane direction was measured using a phase difference meter (Axoscan).

4) Pencil Hardness

Using a pencil hardness tester, the surface of the polarizing plate was reciprocated five times under a load of 500 g according to the measurement standard JIS K5400, and the hardness without scratches was confirmed.

5) scratch resistance

The steel wool # 0000 was subjected to a constant load, reciprocated 10 times, and a load without scratches was observed.

6) Curl characteristics

Each polarizing plate was cut into 10 cm x 10 cm, stored at room temperature for 24 hours, and then placed on a plane, and the average distance of each side of each corner was measured from the plane.

7) Cylindrical bending test

Each polarizing plate was sandwiched in a cylindrical ellipse having a diameter of 5 mm, and then the presence or absence of cracks was judged to be OK, the case where no crack occurred was evaluated as OK, and the case where a crack occurred was evaluated as X.

The results of the physical properties measurement are shown in Table 1 below.

Example 4 Example 5 Example 6 Comparative Example 2 Comparative Example 3 Polarizer thickness 91 탆 92 탆 90 탆 111 탆 105 탆 Transmittance 42.9% 43.1% 42.7% 42.6% 42.7% Hayes 0.2 0.3 0.2 0.3 0.2 Phase difference 0.2 nm 0.3 nm 0.2 nm 2.3 nm 2.2 nm Pencil hardness 3H 3H 3H 3H HB My scratch 500g 500g 500g 500g 50g Curl characteristic 0.5mm 0.4mm 0.3mm 28.5 mm 0.1mm Flex Test OK OK OK X OK

As shown in Table 1, the polarizing plate of the example of the present invention showed good properties in all properties. In particular, as compared with the conventional protective film comprising TAC and the coating layer as in Comparative Example 2, it can be used for a display device which is required to be thinned because of its low thickness, high hardness, excellent curling property and flexibility.

Claims (9)

A binder comprising a polyfunctional acrylate-based monomer, an acrylate-based oligomer having an elongation of 5 to 200%, and an acrylate-based elastic polymer having an elongation of 5 to 200%; And
A resin composition comprising a photoinitiator.
The method of claim 1, wherein the polyfunctional acrylate monomer is 20 to 70 parts by weight, the acrylate oligomer having an elongation of 5 to 200% is 20 to 70 parts by weight, 1 to 50 parts by weight of the acrylate-based elastic polymer, and 1 to 10 parts by weight of the photoinitiator.
The method of claim 1, wherein the polyfunctional acrylate monomer is selected from the group consisting of hexane diol diacrylate (HDDA), tripropylene glycol diacrylate (TPGDA), ethylene glycol diacrylate (EGDA), trimethylolpropane triacrylate ), Trimethylolpropane ethoxy triacrylate (TMPEOTA), glycerin propoxylated triacrylate (GPTA), pentaerythritol tetraacrylate (PETA), and dipentaerythritol hexaacrylate (DPHA) And at least one selected from the group consisting of the resin (A) and the resin (B).
The method of claim 1, wherein the acrylate oligomer has two or more acrylate functional groups and is modified with at least one selected from the group consisting of ethylene oxide, propylene oxide, and caprolactone .
delete The resin composition according to claim 1, wherein the acrylate-based elastic polymer comprises at least one of a polyrotase or a urethane acrylate-based polymer.
[7] The method of claim 6, wherein the polyrotaxane is a cyclic compound having a caprolactone group to which an acrylate compound is introduced at the terminal thereof; Linear molecules passing through the cyclic compound; And a blocking group disposed at both ends of the linear molecule to prevent the cyclic compound from escaping.
The resin composition according to claim 1, further comprising an organic solvent.
The resin composition according to claim 1, which is used for forming a polarizer protective film.