WO2013180497A1 - Aqueous composition, optical film comprising same, and polarizer and liquid crystal display device using the optical film - Google Patents

Abstract

The present invention relates to an aqueous primer composition comprising: 100 weight parts of a urethane resin; 1 weight part to 100 weight parts of polyvinyl alcohol; and 0.1 to 10 weight parts of water-dispersible fine particles, with the remainder being water. The present invention also relates to an optical film comprising the aqueous primer composition and to a polarizer and liquid crystal display device using the optical film.

Description

Aqueous composition, optical film comprising same, polarizing plate and liquid crystal display using same

The present invention relates to an aqueous primer composition, an optical film including the same, a polarizing plate and a liquid crystal display device using the same, which has excellent adhesion to an acrylic film and does not impair the optical properties and durability of the optical film when applied to the optical film. An optical film including a primer composition, and a polarizing plate and a liquid crystal display device using the same.

A liquid crystal display (LCD) device is a display device that expresses pixels using a principle of selectively passing light by a change in polarization action according to an arrangement of liquid crystals positioned between polarizing plates. If only the polarizing plate is applied to the liquid crystal display without a separate optical film, brightness or contrast may be remarkably lowered or light leakage may occur when viewing a screen in an inclined direction. In order to solve this problem, a method of including an optical compensation film such as a retardation film or a viewing angle compensation film in the polarizing plate, or including an optical compensation film between the polarizing plate and the liquid crystal panel is used. As such, an optical compensation film such as a retardation film and a viewing angle compensation film is inserted between the polarizing plate and the liquid crystal display device to reduce color change of the liquid crystal display (LCD) device, to enlarge the viewing angle, and to improve brightness.

Meanwhile, the optical compensation films may be classified into a liquid crystal film made by stretching a polymer film and applying a polymerizable liquid crystal compound on a plastic substrate and drying and irradiating ultraviolet rays to cure the polymer film. .

The stretched film and liquid crystal film used as an optical film have optical anisotropy. In this case, the method for imparting optical anisotropy to the stretched film may be generally performed by adjusting a mixture ratio of a material having a positive phase difference and a material having a negative phase difference and a draw ratio of the polymer film. In addition, the liquid crystal film may be divided into disc-type liquid crystals and rod-type liquid crystals according to the shape of the liquid crystal molecules. Among them, in particular, the liquid crystal films may be planar, homeotropic, or inclined. Various orientation forms exist, such as tilted, splay and cholesteric. Therefore, a method of imparting optical anisotropy to the liquid crystal film may generally be performed by a method of adjusting the alignment form.

On the other hand, in the conventional liquid crystal film, as shown in FIG. 1, after forming the alignment film 2 on the TAC base material 3, the alignment film is orientated by rubbing treatment or polarized light irradiation, and polymerized thereon. It was produced in such a manner that the liquid crystal compound was applied, dried, and cured to form a liquid crystal layer (1). However, in this case, due to the vulnerability to moisture of the TAC film has caused durability problems due to dimensional change in long-term use.

In order to compensate for these disadvantages, attempts have been made to apply a film having a high moisture resistance and low retardation properties to a liquid crystal film such as cyclo olefin (Cylic Olefin) resin or acrylic resin. In particular, it is known that an acrylic film may have advantages in terms of cost as well as optical properties and durability. However, unlike the triacetyl cellulose (TAC) substrate, the acrylic film has a low surface roughness due to the high draw ratio, and the surface is dense, making it difficult to penetrate the coating layer, which causes the acrylic film, the alignment layer, and the liquid crystal. There is a problem that the adhesion between the layers is not good. In addition, in the case of the acrylic film, there is also a problem in that the solvent resistance is poor, and the acrylic film is damaged by the organic solvent included in the alignment film composition, so that the alignment characteristics are hardly obtained.

Therefore, while using an acrylic film as a base film, the development of the technology which can manufacture the optical film which is excellent in the adhesive force with an orientation film and a liquid crystal layer, is excellent in solvent resistance, and has the outstanding orientation characteristic is urgent.

The present invention is to solve the above problems, to provide an aqueous primer composition that can improve the solvent resistance of the acrylic film and the alignment film, an optical film comprising the same, a polarizing plate and a liquid crystal display using the same do.

In order to solve the above problems, a first aspect of the present invention provides an aqueous primer composition comprising 100 parts by weight of a urethane resin, 1 to 100 parts by weight of polyvinyl alcohol, 0.1 to 10 parts by weight of water-dispersible fine particles and the balance of water. .

In this case, the solid content of the aqueous primer composition is preferably about 1 part by weight to about 50 parts by weight based on 100 parts by weight of the total aqueous primer composition. In addition, in the aqueous primer composition, the weight average molecular weight of the urethane resin is 10,000 to 200,000, preferably containing a carboxyl group. In addition, the urethane resin may be obtained by reacting a polyol and an isocyanate.

The second aspect of the present invention provides an optical film including a primer layer formed using the aqueous primer composition.

A third aspect of the present invention provides a polarizing plate comprising the optical film.

A fourth aspect of the present invention provides a display device including the polarizing plate.

The acrylic film including the primer layer formed by using the aqueous primer composition of the present invention is very excellent in adhesion and solvent resistance with the alignment film can be usefully used as a base film of the liquid crystal film.

In addition, when using the liquid crystal film as a polarizer protective film, using the aqueous primer composition according to the present invention, by imparting excellent adhesion between the polarizer and the acrylic film, thereby inhibiting optical properties such as light transmittance of the manufactured polarizing plate There is an advantage to improve the durability without doing.

1 shows the structure of a conventional optical film.

2 illustrates a structure of an optical film according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below. In addition, the embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art. Shape and size of the elements in the drawings may be exaggerated for more clear description.

According to the first aspect of the present invention, there is provided an aqueous primer composition comprising 100 parts by weight of a urethane resin, 1 part by weight to 100 parts by weight of polyvinyl alcohol, 0.1 to 10 parts by weight of water-dispersible fine particles and the balance of water. On the other hand, in the present specification, the content of the urethane resin, polyvinyl alcohol and water dispersible fine particles means a solid content.

In the present specification, when the content of the total water-based primer composition is 100 parts by weight, it means the parts by weight except for the content of urethane resin, polyvinyl alcohol, water dispersible fine particles and components that may be optionally included. That is, after adding the urethane resin, polyvinyl alcohol, water dispersible fine particles and components that may be optionally included, it means that the content of the total aqueous primer composition to 100 by adding water.

It is preferable that the water-based primer composition of this invention is water-soluble in the point which does not require introduction of explosion-proof equipment.

On the other hand, the weight average molecular weight of the urethane resin is preferably 10,000 to 200,000. When the weight average molecular weight of the urethane resin satisfies the above numerical range, there is an advantage in that the adhesion is excellent and the urethane synthesis is easy.

In addition, the urethane resin is preferably obtained by reacting a polyol and an isocyanate.

In this case, the polyol is not particularly limited as long as it has two or more hydroxyl groups in the molecule, and any appropriate polyol may be employed. For example, one or more selected from the group consisting of polyester polyols, polyether polyols, polycarbonate diols, and the like may be used in combination, but is not limited thereto.

In the aqueous primer composition of the present invention, in the examples of the polyol for obtaining the urethane resin, the polyester polyol is preferably obtained by reacting the polybasic acid component and the polyol component.

Here, the polybasic acid component for obtaining the polyester polyol is ortho-phthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6 -Aromatic dicarboxylic acids such as naphthalenedicarboxylic acid, biphenyldicarboxylic acid, tetrahydrophthalic acid, oxalic acid, succinic acid, malonic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, Aliphatic dicarboxylic acids such as sebacic acid, linolenic acid, maleic acid, fumaric acid, mesaconic acid and itaconic acid; Alicyclic dicarboxylic acids such as hexahydrophthalic acid, tetrahydrophthalic acid, 1,3-cyclohexanedicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid; Or a combination of one or more selected from the group consisting of reactive derivatives such as acid anhydrides, alkyl esters, and acid halides thereof, but is not limited thereto.

Further, in order to obtain the polyester polyol, the polyol component is ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentane Diol, 1,6-hexanediol, 1,8-octanediol, 1-10-decanediol, 4,4'-dihydroxyphenylpropane, 4,4'-dihydroxymethylmethane, diethylene glycol, tri Ethylene glycol, polyethylene glycol, dipropylene glycol, polypropylene glycol, 1,4-cyclohexanedimethanol, 1,4-cyclohexanediol, bisphenol A, bisphenol F, glycerin, 1,1,1-trimethylolpropane, 1 It may be, but is not limited to, one selected from the group consisting of 2,5-hexatriol, pentaerythritol, glucose, sucrose, and sorbitol.

In the aqueous primer composition of the present invention, among the examples of the polyol for obtaining the urethane resin, the polyether polyol is preferably obtained by ring-opening polymerization of an alkylene oxide to a polyhydric alcohol to add the polyol. The polyhydric alcohol may be used in combination of one or more selected from the group consisting of ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, glycerin, and trimethylolpropane, but is not limited thereto.

In the aqueous primer composition of the present invention, in the examples of the polyol for obtaining the urethane resin, the polycarbonate polyol may be one selected from the group consisting of poly (hexamethylene carbonate) glycol and poly (cyclohexane carbonate) glycol. This is not restrictive.

Meanwhile, the isocyanate is toluene diisocyanate (TDI), 4,4-diphenylmethane diisocyanate (MDI), 1,5-naphthalene diisocyanate (NDI), tolidine diisocyanate (TODI), hexamethylene diisocyanate (HMDI ), Isopron diisocyanate (IPDI), p-phenylene diisocyanate, 1,4-diisocyanate and xylene diisocyanate (XDI) may be used in combination, but is not limited thereto.

In the aqueous primer composition according to the present invention, the urethane resin preferably includes a carboxyl group. Here, the carboxyl group forms an anion part to disperse in water when preparing the water-dispersed urethane, and serves to enhance the adhesion to the polarizer.

As described above, the urethane resin including a carboxyl group may be obtained by reacting the polyol and the isocyanate with a chain extender having a free carboxyl group. In this case, the chain extender having a carboxyl group may be, for example, dihydroxycarboxylic acid or dihydroxysuccinic acid, but is not limited thereto.

In addition, the dihydroxycarboxylic acid is a combination of one or more from the group consisting of dialkylol alkanoic acid such as dimethylol alkanoic acid (dimethylol acetic acid, dimethylol butanoic acid, dimethylol propionic acid, dimethylol butyric acid and dimethylol pentanoic acid) It can be used, but is not limited thereto.

In addition, arbitrary appropriate methods can be employ | adopted for the manufacturing method of the said urethane resin. For example, the one-shot method of making each said component react at once, the multistage method of making it react in steps, etc. are mentioned. When a urethane resin has a carboxyl group, in order to introduce | transduce a carboxyl group easily, it is preferable to manufacture by the multistage method. Further, any suitable urethane reaction catalyst may be used in the production of the urethane resin.

In the production of the urethane resin, in addition to the above components, other polyols, other chain extenders, or a combination thereof may be reacted.

In this case, the other polyol is not limited as long as the number of hydroxy groups is three or more, but may be, for example, sorbitol, glycerin, trimethylol ethane, trimethylol propane or pentaerythritol.

In addition, the other chain extender, for example, ethylene glycol, diethylene glycol, triethylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, 1 Glycols such as 6-hexanediol and propylene glycol; Aliphatic diamines such as ethylenediamine, propylenediamine, hexamethylenediamine, 1,4-butanediamine, and aminoethyl ethanolamine; Alicyclic diamines such as isophorone diamine and 4,4'-dicyclohexyl methanediamine; Aromatic diamines such as xylylenediamine, tolylenediamine, and the like, but are not limited thereto.

Meanwhile, a neutralizing agent may be used to improve the stability of the urethane resin in water when the urethane resin is prepared. The neutralizing agent is selected from the group consisting of, for example, ammonia N-methylmorpholine, triethylamine, dimethylethanolamine, methyldiecanolamine, criethanolalkyne, morpholine, tripropylamine, ethanolamine and triisopropanolamine. One or more species may be used in combination, but the present invention is not limited thereto.

Moreover, when manufacturing the said urethane resin, It is preferable to use the organic solvent which is inert with respect to the said isocyanate, and is compatible with water. In this case, the organic solvent may be an ester solvent such as ethyl acetate and ethyl cellosolve acetate; Ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone; One or more selected from the group consisting of ether solvents such as dioxane tetrahydrofuran may be used in combination, but is not limited thereto.

Next, the polyvinyl alcohol preferably has a weight average molecular weight of 2,000 to 40,000. When the weight average molecular weight of polyvinyl alcohol satisfies the above numerical range, solvent resistance is improved, and viscosity does not rise, so coating and drying are easy.

In addition, the content of the polyvinyl alcohol may include 1 part by weight to 100 parts by weight, preferably 10 parts by weight to 100 parts by weight, more preferably 50 parts by weight to 100 parts by weight, based on 100 parts by weight of the urethane resin. . When the content of polyvinyl alcohol satisfies the above numerical range, solvent resistance is improved, adhesion with acrylic is good, and the content of polyvinyl alcohol is not high, so the viscosity is constant, so leveling is easy during coating.

On the other hand, the polyvinyl alcohol is not particularly limited as long as it is commonly used in the art to improve solvent resistance. For example, products such as Gohsefimer Z-100 ^® , Z-200 ^® , Z-200H ^® , Z-210 ^® , Z-220 ^® or Z-320 ^{® from} Nippon Synthetic Chemical can be used.

Next, as the fine particles that can be used in the present invention, any suitable fine particles can be used, and preferably water-dispersible fine particles are used. Specifically, both inorganic fine particles and / or organic fine particles can be used.

Here, the inorganic fine particles may be, for example, inorganic oxides such as silica, titania, alumina, zirconia, antimony, and the like, but is not limited thereto. In addition, the organic fine particles may be, for example, a silicone resin, a fluorine resin, a (meth) acrylic resin, a crosslinked polyvinyl alcohol, or a melamine resin, but is not limited thereto.

In particular, in the aqueous primer composition according to the present invention, the water-dispersible fine particles are preferably silica. The silica has an advantage of more excellent blocking inhibitory ability, excellent transparency, no haze, no coloring, and a smaller influence on the optical properties of the polarizing plate. In addition, since silica has good dispersibility and dispersion stability with respect to the aqueous primer composition, the workability at the time of forming the primer layer may also be excellent.

On the other hand, the average diameter of the water-dispersible fine particles, that is, the average primary particle diameter may be, for example, 10nm to 200nm, 15nm to 150nm or 20nm to 100nm. When the average diameter of the water-dispersible fine particles satisfies the above numerical range, the aggregation rate and precipitation occurrence rate of the water-dispersible particles in the aqueous primer solution are lowered, so that the solution is excellent in stability, and the dispersion of the water-dispersible particles in the aqueous primer solution is evenly distributed. As a result, it is possible to prevent the particles from agglomerating, thereby preventing scattering of light in the visible light region and increasing the haze.

That is, by using water-dispersible fine particles having a particle diameter in the above range, irregularities are appropriately formed on the surface of the primer layer, and in particular, the frictional force at the contact surface between the acrylic film and the primer layer and / or the primer layers can be effectively reduced. Can be. As a result, when winding up the film in which the said primer layer was formed, blocking blocking ability may be further excellent.

Since the primer composition of the present invention is water-based, the water-dispersible fine particles are preferably blended into the water dispersion. Specifically, when silica is used as the water dispersible fine particles, it is preferably blended as colloidal silica. As a colloidal silica, the product marketed in the said technical field can be used as it is, For example, Snowtex series by Nissan Chemical Industries, Ltd., AEROSIL series by Air Products, epostar series by Japanese catalyst, soliostar RA series, or Ranco LSH series and the like can be used.

At this time, the content of the water-dispersible fine particles may be 0.1 parts by weight to 10 parts by weight or 0.1 parts by weight to 8 parts by weight with respect to 100 parts by weight of the urethane resin. When the content of the water-dispersible fine particles satisfies the numerical range, the blocking incidence rate is significantly lowered and the haze is reduced to obtain a film having excellent optical properties.

Next, the aqueous primer composition of the present invention does not particularly limit the solid content. However, the solids content may include, for example, 1 part by weight to 50 parts by weight, preferably 5 parts by weight to 30 parts by weight, more preferably 10 parts by weight to 20 parts by weight, based on 100 parts by weight of the aqueous primer composition. Can be. When the solid content in the aqueous primer composition according to the present invention satisfies the numerical range, the adhesion is improved, the viscosity is not high, the leveling is good at the time of coating, and the drying time is short. In this case, the solid content means the solid content of the entire aqueous primer composition.

According to a second aspect of the present invention, there is provided an optical film including a primer layer formed on at least one surface of an acrylic film by using the aqueous primer composition.

In the present invention, the optical film generally refers to a film that performs an optical function, and in the case of a film for performing a specific optical function such as a polarizing plate as well as a narrow transparent film having a light transmittance of 80% or more, the light transmittance is 50%. The following optical film is also included.

The acrylic film usable in the present invention may be a single layer or a structure in which two or more films are laminated.

More specifically, the acrylic film may contain a (meth) acrylate resin. At this time, the film containing (meth) acrylate type resin can be obtained by shape | molding the molding material which contains (meth) acrylate type resin as a main component, for example by extrusion molding.

In addition, the (meth) acrylate-based resin is a resin containing a (meth) acrylate-based unit as a main component, as well as a (meth) acrylate-based homopolymer resin consisting of (meth) acrylate-based units It is a concept that the copolymer resin copolymerized with another monomer unit other than a unit, and the blend resin which another resin was blended with the above-mentioned (meth) acrylate type resin are also included.

In this case, the (meth) acrylate-based unit may be, for example, an alkyl (meth) acrylate-based unit. Here, the alkyl (meth) acrylate-based unit means both an alkyl acrylate-based unit and an alkyl methacrylate-based unit, the alkyl group of the alkyl (meth) acrylate-based unit is preferably 1 to 10 carbon atoms, It is more preferable that it is C1-C4.

On the other hand, as a monomeric unit copolymerizable with the said (meth) acrylate type unit, an aromatic vinyl type unit, the 3-6 membered heterocyclic unit substituted by the carbonyl group, an acrylic acid unit, glycidyl unit, etc. are mentioned.

The aromatic vinyl unit is, for example, styrene, α-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, 2-methyl-4-chlorostyrene , 2,4,6-trimethylstyrene, cis-β-methylstyrene, trans-β-methylstyrene, 4-methyl-α-methylstyrene, 4-fluoro-α-methylstyrene, 4-chloro-α-methylstyrene , 4-bromo-α-methylstyrene, 4-t-butylstyrene, 2-fluorostyrene, 3-fluorostyrene, 4-fluorostyrene, 2,4-difluorostyrene, 2,3,4,5 , 6-pentafluorostyrene, 2-chlorostyrene, 3-chlorostyrene, 4-chlorostyrene, 2,4-dichlorostyrene, 2,6-dichlorostyrene, octachlorostyrene, 2-bromostyrene, 3-bro At least one monomer selected from the group consisting of mostyrene, 4-bromostyrene, 2,4-dibromostyrene, α-bromostyrene, β-bromostyrene, 2-hydroxystyrene and 4-hydroxystyrene From the field But it may be also a unit, and the like. Especially, it is preferable that it is a unit derived from styrene or (alpha) -methyl styrene.

Meanwhile, the 3 to 6 membered heterocyclic unit substituted with the carbonyl group may be, for example, a unit derived from monomers such as a lactone ring, glutaric anhydride, glutarimide, maleic anhydride, maleimide, and the like.

Meanwhile, the resin that may be blended with the (meth) acrylate resin is not particularly limited, and may be, for example, a phenoxy resin, a polycarbonate resin, or the like.

In addition, the manufacturing method of the said (meth) acrylate type resin film is not specifically limited, For example, (meth) acrylate type resin, another polymer, an additive, etc. are fully mixed by arbitrary suitable mixing methods, and a thermoplastic resin is carried out. It is also possible to prepare the composition by film molding or to prepare a (meth) acrylate-based resin and other polymers, additives, etc. in a separate solution, and then to mix to form a uniform mixed solution and then to film-form it. have.

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

Next, as a method of the said film shaping | molding, arbitrary suitable film shaping | molding methods, such as the solution casting method (solution casting method), the melt extrusion method, the calender method, or the compression molding method, are mentioned, for example. Among these film forming methods, a solution cast method (solution casting method) or a melt extrusion method is preferable.

At this time, the solvent used for the solution casting method (solution casting method) is, for example, aromatic hydrocarbons such as benzene, toluene, xylene; Aliphatic hydrocarbons such as cyclohexane and decalin; Esters such as ethyl acetate and butyl acetate; Ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone; Alcohols such as methanol, ethanol, isopropanol, butanol, isobutanol, methyl cellosolve, ethyl cellosolve and butyl cellosolve; Ethers such as tetrahydrofuran and dioxane; Halogenated hydrocarbons such as dichloromethane, chloroform and carbon tetrachloride; Dimethylformamide; Dimethyl sulfoxide, etc. are mentioned. These solvents may be used independently or may use 2 or more types together.

Moreover, as an apparatus for implementing the said solution casting method (solution casting method), a drum type casting machine, a band type casting machine, a spin coater, etc. are mentioned, for example. Examples of the melt extrusion method include a T-die method and an inflation method. Molding temperature becomes like this. Preferably it is 150-350 degreeC, More preferably, it is 200-300 degreeC.

Under the present circumstances, when shape | molding a film by the said T die method, a T die can be attached to the front-end | tip of a well-known single screw extruder or a twin screw extruder, the film extruded in film shape can be rolled, and a roll-shaped film can be obtained. Under the present circumstances, you may uniaxially stretch by adjusting the temperature of a winding roll suitably and extending | stretching in an extrusion direction. Moreover, simultaneous biaxial stretching, sequential biaxial stretching, etc. can also be performed by extending | stretching a film in the direction perpendicular | vertical to an extrusion direction.

On the other hand, the acrylic film may be any of an unstretched film or a stretched film. In the case of a stretched film, it may be a uniaxial stretched film or a biaxially stretched film, and in the case of a biaxially stretched film, it may be either a simultaneous biaxially stretched film or a successive biaxially stretched film. In the case of biaxial stretching, the mechanical strength is improved and the film performance is improved. By mixing another thermoplastic resin, an acryl-type film can suppress an increase of retardation even when extending | stretching, and can maintain optical isotropy.

At this time, it is preferable that extending | stretching temperature is a range near the glass transition temperature of the thermoplastic resin composition which is a film raw material, Preferably it is (glass transition temperature -30 degreeC)-(glass transition temperature +100 degreeC), More preferably, Glass transition temperature-20 DEG C) to (glass transition temperature + 80 DEG C). If the stretching temperature is less than (glass transition temperature-30 ° C), there is a fear that a sufficient stretching ratio may not be obtained. On the contrary, when extending | stretching temperature exceeds (glass transition temperature +100 degreeC), the flow (flow) of a resin composition arises and there exists a possibility of not being able to perform stable extending | stretching.

Moreover, the draw ratio defined by area ratio becomes like this. Preferably it is 1.1-25 times, More preferably, it is 1.3-10 times. If the draw ratio is less than 1.1 times, there is a fear that it does not lead to the improvement of the toughness accompanying stretching. When a draw ratio exceeds 25 times, there exists a possibility that the effect by raising a draw ratio may not be recognized.

Further, the stretching speed is preferably 10 to 20,000% / min, more preferably 100 to 10,000% / min in one direction. If the stretching speed is less than 10% / min, it takes a long time to obtain a sufficient draw ratio, there is a fear that the manufacturing cost increases. When the stretching speed exceeds 20,000% / min, breakage of the stretched film may occur.

On the other hand, the acrylic film may be subjected to heat treatment (annealing) or the like after the stretching treatment in order to stabilize its optical isotropy or mechanical properties. The heat treatment conditions are not particularly limited and any suitable conditions well known in the art may be employed.

Next, the acrylic film may be subjected to a surface treatment to improve the adhesion if necessary, for example, at least one surface selected from the group consisting of alkali treatment, corona treatment, and plasma treatment on at least one surface of the acrylic film. Processing can be performed.

On the other hand, the primer layer is formed by the above-described water-based primer composition of the present invention, it may be formed by a method of applying the water-based primer composition on at least one side of the acrylic film. Since specific details of the aqueous primer composition are the same as described above, detailed descriptions thereof will be omitted.

On the other hand, the primer layer, for example, may be formed by a coating layer forming method generally used in the art, such as wire coating, bar coating, spin coating, the primer layer forming method is not particularly limited.

On the other hand, the optical film of the present invention may be formed on one surface of the acrylic film, or may be formed on both sides. According to the researches of the present inventors, it was found that the aqueous primer composition of the present invention not only improves the adhesion between the alignment film and the acrylic film, but also can perform the function of improving the adhesion between the polarizer and the acrylic film. Therefore, when forming the primer layer by the water-based primer composition of the present invention on both sides of the acrylic film, it is possible to improve both the adhesive force between the polarizer and the acrylic film and the adhesive force between the acrylic film and the alignment film.

Meanwhile, as shown in FIG. 2, the optical film of the present invention may further include an alignment layer 2 and a liquid crystal layer 1 on the primer layer 4 formed on at least one surface of the acrylic film 5. Can be.

In this case, the alignment layer is formed by applying various alignment layer compositions known in the art, for example, a composition for a photo alignment layer or a composition for a rubbing alignment layer on a primer layer, and then aligning the same through a rubbing treatment or a polarization irradiation treatment. Can be formed. The alignment film composition or the alignment film forming method usable in the present invention is not particularly limited, and various alignment film compositions and alignment film forming methods well known in the art may be used without limitation.

In this case, the method of applying the alignment layer composition may be performed through a method well known in the art, for example, a wire coating bar coating, a spin coating, or the like.

In addition, after the alignment layer composition is applied, a drying process may be performed to remove the remaining solvent, wherein the drying may be performed at 70 ° C. to 150 ° C. for at least 30 seconds. Although the drying temperature and time are not particularly limited, the alignment film can be sufficiently dried without causing deformation of the substrate when the above conditions are satisfied.

In addition, according to the kind of alignment film used, the said orientation process can use suitably methods, such as a rubbing orientation and a photo-alignment, and if necessary, in order to improve an orientation, both rubbing orientation and a photo-alignment can also be used. In this case, the rubbing alignment may be performed by rubbing the surface of the alignment layer with a cloth, and the like, and the optical alignment may be performed by irradiating the polarized ultraviolet rays through the polarizing plate between the alignment layer and the light source. In this case, the ultraviolet irradiation may be performed in the atmosphere or in a nitrogen atmosphere in which oxygen is blocked to increase the reaction efficiency. In the case of UV irradiation, a medium or high pressure mercury ultraviolet lamp or a metal halide lamp having an intensity of 80 w / cm or more may be used.

In the present invention, the present invention is not limited thereto, but an alignment layer composition including a photoreactive polymer, a polyfunctional monomer, an initiator, and a solvent may be used as the alignment layer composition, and the alignment layer composition may further include a crosslinking agent, if necessary. Can be. More specifically, the alignment film composition of the present invention is not limited thereto, but is 0.05 part by weight to 10 parts by weight of the polyfunctional monomer, 0.05 part by weight to 10 parts by weight of the photoreactive polymer, and photoinitiator 0.01 to 100 parts by weight of the alignment film composition. It may include 5 parts by weight to 5 parts by weight and the remainder of the solvent, if necessary, may further comprise 0.01 parts by weight to 2 parts by weight of the crosslinking agent.

As the polyfunctional monomer, a mixed polyfunctional monomer which is a mixture of a polyfunctional triazine monomer and a polyfunctional acrylic monomer may be used. The mixing ratio of the triazine monomer and the acrylic monomer in the mixed polyfunctional monomer of the polyfunctional triazine monomer and the polyfunctional acrylic monomer is not particularly limited, and these two components are used as long as the triazine monomer and the acrylic monomer are used together. Mixed multifunctional monomers mixed in any of these proportions can be used.

Moreover, the said polyfunctional triazine monomer is 1,3,5-triallyl-1,3,5-triazinene-2,4,6- trione, 1,3,5-triacryl, for example. Yl-1,3,5-triazine, 1,3,5-tris (2-oxynalylmethyl) -1,3,5-triazinein-2,4,6-trione, 2- {3 , 5-bis [2- (acryloyloxy) ethyl] -2,4,6-trioxo-1,3,5-triazinan-1-yl} -ethyl acrylate, and 3- (3-allyl One or more selected from the group consisting of -5- (2-cyano-ethyl) -2,4,6-trioxo- (1,3,5) triazin-1-yl) -propionitrile can be used However, it is not limited thereto.

Furthermore, the multifunctional acrylic monomer may be, for example, triacrylate (particularly pentaerythritol triacrylate, PETA), tetraacrylate (particularly pentaerythritol tetraacrylate). (Pentaerythritol tetraacrylate, PETTA) and hexaacrylate (particularly dipentaerythritol hexaacrylate, DPHA) may be used, but is not limited thereto. . Meanwhile, the content of the mixed multifunctional monomer may be 0.05 parts by weight to 10 parts by weight based on the photoalignment film composition. When the content of the polyfunctional acrylic monomer satisfies the above numerical range, the interlayer adhesion between the photoalignment film and the base film is excellent, thereby preventing the problem of exfoliation of the photoalignment film and realizing excellent orientation.

Meanwhile, the photoreactive polymer may be, for example, a norbornene-based photoreactive polymer including a cinnamate group. In this case, the norbornene-based photoreactive polymer containing the cinnamate group is, for example, polynorbornene cinnamate, polynorbornene alkoxycinnamate (alkoxy group having 1 to 20 carbon atoms), polynorbornene allylyloxycinnamate, poly And one or more selected from the group consisting of norbornene fluorinated cinnamates, polynorbornene chlorinated cinnamates, and polynorbornene discinnamates. Further, the content of the photoreactive polymer may be 0.05 to 10 parts by weight, 1 to 10 parts by weight or 0.1 to 10 parts by weight based on the photoalignment film composition. When the content of the photoreactive polymer satisfies the numerical range, an optical alignment film having excellent alignment can be obtained.

The photoinitiator can be used as long as it can induce a radical reaction, more preferably water-soluble. For example, IGACURE 2959 (IRGACURE 2959, 2-Hydroxy-1- [4- (2-hydroxyethoxy) phenyl] -2-methyl-1-propanone) supplied by Ciba-Geigy, Igacure 500 (IRGACURE 500, 1-Hydroxy-cyclohexyl-phenyl-ketone + Benzophenone), Igacure 754 (IRGACURE 754, oxyphenyl-acetic acid 2- [2 oxo-2 phenyl-acetoxy-ethoxy] -ethyl ester and oxy- phenyl-acetic 2- [2-hydroxyethoxy] -ethyl ester) or Igacure OXE02 (IRGACURE OXE02, 1- (1-6-benzoyl-9-ethyl-9H-carbazol-3-yl) ethylideneaminooxy) ethanone, etc. It is not limited to this. Meanwhile, the content of the photoinitiator may be 0.01 parts by weight to 5 parts by weight based on the photoalignment film composition. When the content of the photoinitiator satisfies the above numerical range, the crosslinking reaction effect by the multifunctional monomer can be expected, and the orientation of the liquid crystal increases.

In addition, the said solvent should just be what can melt | dissolve the said polyfunctional monomer and photoreactive polymer, The kind is not specifically limited. For example, as said solvent, For example, halogenated hydrocarbons, such as chloroform, tetrachloroethane, trichloroethylene, tetrachloroethylene, chlorobenzene; Aromatic hydrocarbons such as benzene, toluene, xylene, methoxybenzene and 1,2-dimethoxybenzene; Ketones such as acetone, methyl ethyl ketone, cyclohexanone and cyclopentanone; Alcohols such as isopropyl alcohol and n-butanol; Cellosolves such as methyl cellosolve, ethyl cellosolve and butyl cellosolve; Organic solvents such as water, or mixtures thereof may be used.

On the other hand, the crosslinking agent may be used such as aldehyde (aldehyde), dialdehyde (dialdehyde) or isocyanate (isocyanate), but is not limited thereto. The aldehydes or dialdehydes may be, for example, acrylaldehyde, oxalaldehyde, 2-methylacrylaldehyde, 2-oxopropanal or glutaraldehyde, but are not limited thereto. In addition, the isocyanates may be, for example, 2-isocyanatoethyl 2-methyl acrylate, 1,4-diisocyanatobutane, 1,4-diisocyanatobenzene or 1,3-diisocyanatobenzene, and the like. However, the present invention is not limited thereto. The crosslinking agents may be used alone or in a mixture of two or more thereof.

Further, the content of the crosslinking agent may be 0 to 2 parts by weight, preferably 0.01 to 2 parts by weight, based on the entire alignment layer composition. When the crosslinking agent content satisfies the numerical range, sufficient crosslinking reaction can be induced to provide excellent moisture resistance, excellent solution stability, and uniform coating property, and particularly good alignment force of the liquid crystal after the alignment treatment. .

Next, the liquid crystal layer may be formed by a method of forming a liquid crystal layer that is well known in the art, for example, applying a liquid crystal compound solution on an alignment treated layer and then fixing the liquid crystal compound solution.

In this case, the coating of the liquid crystal compound solution may be performed through general methods well known in the art, for example, wire coating bar coating, spin coating, and the like.

In addition, after the liquid crystal compound solution is applied, a drying process may be performed to remove the remaining solvent, wherein the drying may be performed at 25 ° C. to 120 ° C. for at least 1 minute. Although the drying temperature and time are not particularly limited, it is more preferable to satisfy the above drying conditions from the viewpoint of improving the liquid crystal alignment degree and preventing the occurrence of defects.

On the other hand, the fixing is to fix the alignment of the liquid crystal, for example, may be performed by polymerizing, curing the liquid crystal compounds through ultraviolet irradiation. In this case, the ultraviolet irradiation may be performed in the atmosphere or in a nitrogen atmosphere in which oxygen is blocked to increase the reaction efficiency. Typically ultraviolet irradiator may be used a medium or high pressure mercury ultraviolet lamp, or a metal halide lamp having an intensity of 80 w / cm or more. In the ultraviolet irradiation, a cold mirror or other cooling device may be provided between the substrate and the ultraviolet lamp so that the surface temperature of the liquid crystal layer is within a temperature range having a liquid crystal state.

Meanwhile, as the liquid crystal compound solution, liquid crystal compound solutions commonly used in the art may be used without limitation. For example, a liquid crystal compound solution prepared by dissolving the polymerizable liquid crystal compound and a photoinitiator in an organic solvent may be used. Can be used.

In this case, as the polymerizable liquid crystal compound, a material well known in the art may be used as a material having an acrylate group polymerizable by photoreaction, but is not limited thereto. For example, cyano biphenyl, cyano phenyl cyclohexane, cyano phenyl ester, benzoic phenyl ester, phenyl pyrimidine-based acrylates that exhibit nematic or cholesteric liquid phases at room temperature or high temperature. It may be a low molecular liquid crystal. These materials may be used alone or in a mixture of two or more. The content of the polymerizable liquid crystal compound in the liquid crystal compound solution is not particularly limited, but may be 5 parts by weight to 70 parts by weight, preferably 5 parts by weight to 50 parts by weight, per 100 parts by weight of the liquid crystal compound solution. When the content of the polymerizable liquid crystal compound satisfies the numerical range, staining is significantly reduced, and the amount of the solvent is insufficient to prevent the problem of precipitation of the polymerizable liquid crystal compound.

In addition, the photoinitiator can be used without limitation as long as it is well known in the art, for example, Igacure 907 (IRGACURE 907) and the like can be used. Meanwhile, the content of the photoinitiator is preferably about 3 parts by weight to about 10 parts by weight based on 100 parts by weight of the polymerizable liquid crystal compound contained in the liquid crystal compound solution. When the content of the photoinitiator satisfies the numerical range, sufficient curing is possible by irradiating ultraviolet rays, and the liquid crystal alignment may be prevented from being changed by the influence of the photoinitiator.

In addition to the photoinitiator, a chiral agent, a surfactant, a polymerizable monomer or a polymer, etc. may be added to the liquid crystal compound solution if necessary so long as the liquid crystal alignment is not prevented.

On the other hand, the organic solvent used for the liquid crystal compound solution production, for example, halogenated hydrocarbons such as chloroform, tetrachloroethane, trichloroethylene, tetrachloroethylene, chlorobenzene; Aromatic hydrocarbons such as benzene, toluene, xylene, methoxybenzene and 1,2-dimethoxybenzene; Ketones such as acetone, methyl ethyl ketone, cyclohexanone and cyclopentanone; Alcohols such as isopropyl alcohol and n-butanol; Cellosolves such as methyl cellosolve, ethyl cellosolve and butyl cellosolve; Etc., but is not limited thereto. These may be used alone or in mixture of two or more.

According to a third aspect of the present invention, there is provided a polarizing plate comprising the optical film according to the present invention. The polarizing plate of the present invention may include, for example, a polarizer and the above-described optical film of the present invention disposed on at least one surface of the polarizer. More specifically, the polarizing plate of the present invention may include the optical film of the present invention in which an acrylic film, a primer layer, an alignment film layer, and a liquid crystal layer are sequentially stacked on at least one surface of the polarizer.

Such a polarizing plate of the present invention preferably has a light transmittance of 35% to 45% and a polarization degree of 98% or more.

According to a fourth aspect of the present invention, a display device including the polarizing plate is provided.

The display device includes a liquid crystal display device and the like, but if the optical film or the polarizing plate as described above is required, the type thereof is not particularly limited. The display device has a configuration known in the art except for including a primer layer formed using the aqueous primer composition according to the present invention. For example, the display device may include a liquid crystal cell; It may be a liquid crystal display device including a polarizing plate and a backlight unit according to the present invention provided on both sides of the liquid crystal cell.

Example 1

50 g of a urethane resin emulsion (CK-PUD-F (10% solids emulsion) and 111 g of a polyvinyl alcohol aqueous solution (Japanese synthetic chemical Z200, 4.5% solids solution), colloidal silica (Ranco, 20% solids) Aqueous solution) was mixed to prepare an aqueous primer composition having a solid content ratio of 1: 1 of the urethane resin and polyvinyl alcohol. Then, the aqueous primer composition was coated on the corona-treated acrylic film (LG Chem GP-film) at about 1000 nm thickness at # 9 bar and dried at 100 ° C. for 5 minutes to prepare an acrylic film having a primer layer formed thereon. It was.

Next, 5-norbornene-2-methyl- (4-methoxy cinnamate), a photoreactive polymer, dipentaerythritol hexaacrylate, a polyfunctional monomer, and Igacure OXE02 (Switzerland, Ciba-Geigy, Inc.) ) Was dissolved in cyclopentanone at a concentration of 2 parts by weight, 2 parts by weight, and 0.5 parts by weight, respectively, to prepare a photo alignment layer composition.

Then, the photo-alignment layer composition was dried on the primer layer of the acrylic film and then coated with a wire bar to have a thickness of 100 nm, followed by hot air drying in a 70 ° C. drying oven for 2 minutes. Then, a high-pressure mercury lamp of 80w / cm intensity was used as a light source, and a Moxtek wire grid polarizer was placed between the light source and the alignment film so as to emit polarized ultraviolet rays, and then subjected to an alignment treatment by exposing at a speed of 3 m / min. It was cured by ultraviolet irradiation, and a rubbing treatment was completed to impart orientation to the cured alignment film surface, thereby completing the alignment film.

Next, 95 parts by weight of A-PLATE (a planar liquid crystal mixture composed of Merck's cyano biphenyl series, cyano phenyl cyclohexane series, and cyano phenyl ester series acrylate) and the photoinitiator Igacure 907 (Ciba-Geigy, Switzerland) A polymerizable liquid crystal compound solution prepared by dissolving 5 parts by weight of solids mixed in toluene so that the solids content per 100 parts by weight of the total solution was 25 parts by weight was applied on the alignment layer to be 1um thick. After drying for 2 minutes in a drying oven at 60 ° C., a liquid crystal layer was formed by irradiating and curing unpolarized ultraviolet rays with a high-pressure mercury lamp of 80w / cm intensity.

Example 2

An optical film was prepared in the same manner as in Example 1, except that the aqueous primer composition was coated with a # 5 bar to a thickness of about 500 nm.

Example 3

An optical film was manufactured in the same manner as in Example 1, except that the aqueous primer composition was coated with a thickness of about 200 nm with # 3 bar.

Example 4

An optical film was prepared in the same manner as in Example 1, except that the primer layer was formed using an aqueous primer composition adjusted to have a solid ratio of urethane resin and polyvinyl alcohol at 1: 0.5.

Example 5

An optical film was prepared in the same manner as in Example 1, except that the primer layer was formed using an aqueous primer composition adjusted to have a solid ratio of the urethane resin and polyvinyl alcohol to be 1: 0.1.

Comparative Example 1

An optical film was prepared in the same manner as in Example 1, except that the primer layer was formed using an aqueous primer composition containing no polyvinyl alcohol.

Comparative Example 2

An optical film was manufactured in the same manner as in Example 1, except that the primer layer was formed using an aqueous primer composition containing no urethane resin.

Comparative Example 3

An optical film was prepared in the same manner as in Example 1, except that the primer layer was formed using an aqueous primer composition adjusted to have a solid ratio of urethane resin and polyvinyl alcohol at 1: 4.

Experimental Example

1. Adhesion

The adhesive force between the acrylic substrate and the alignment film and the alignment film and the liquid crystal film was evaluated by a cross-cut test method specified in ASTM. The surface of the liquid crystal film was cross-cut in the form of a checkerboard at a 1 mm interval with a knife, and then, the cellophane tape was attached and detached thereon. The results are shown in the following [Table 1]. When O is completely stuck, X means the case where it peels partially or fully.

2. Orientation

The orientation of the liquid crystal layer formed on the photo-alignment film was visually confirmed, and the case where the alignment was not performed was indicated by ×, but the case where the alignment was performed was somewhat different. The results are shown in [Table 1].

Table 1

division	Primer layer thickness	Contains water dispersible fine particles	Solid content ratio of urethane resin and polyvinyl alcohol	Polyvinyl alcohol weight ratio with respect to 100 weight part of urethanes	Base film	Adhesion	Orientation
Example 1	1000 nm	include	1: 1	100	Acrylic film	O	O
Example 2	500 nm	include	1: 1	100	Acrylic film	O	O
Example 3	200 nm	include	1: 1	100	Acrylic film	O	O
Example 4	1000 nm	include	1: 0.5	50	Acrylic film	O	O
5 to implementation	1000 nm	include	1: 0.1	10	Acrylic film	O	O
Comparative Example 1	1000 nm	include	1: 0	0	Acrylic film	O	X
Comparative Example 2	1000 nm	include	0: 1	-	Acrylic film	X	X
Comparative Example 3	1000 nm	include	1: 4	400	Acrylic film	X	O

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

[Description of the code]

1: liquid crystal layer

2: alignment film

3: TAC film

4: primer

5: acrylic film

Claims (14)

1. 100 parts by weight of a urethane resin;

   1 part by weight to 100 parts by weight of polyvinyl alcohol;

   0.1 to 10 parts by weight of the water dispersible fine particles and

   An aqueous primer composition comprising the balance of water.
2. The aqueous primer composition according to claim 1, wherein the solid content is 1 to 50 parts by weight based on 100 parts by weight of the aqueous primer composition.
3. The water-based primer composition of claim 1, wherein the weight average molecular weight of the urethane resin is 10,000 to 200,000.
4. The aqueous primer composition of claim 1, wherein the urethane resin includes a carboxyl group.
5. The aqueous primer composition of claim 1, wherein the urethane resin is obtained by reacting a polyol and an isocyanate.
6. The water-based primer composition of claim 1, wherein the polyvinyl alcohol has a weight average molecular weight of 2,000 to 40,000.
7. The aqueous primer composition of claim 1, wherein the water dispersible fine particles are one or more inorganic fine particles selected from the group consisting of silica, titania, alumina, zirconia, and antimony-based fine particles.
8. The water-based primer composition of claim 1, wherein the water-dispersible fine particles are one or more organic fine particles selected from the group consisting of a silicone resin, a fluorine resin, a (meth) acrylic resin, a crosslinked polyvinyl alcohol, and a melamine resin.
9. The aqueous primer composition of claim 1, wherein an average diameter of the water dispersible fine particles is 10 nm to 200 nm.
10. An optical film comprising a primer layer formed on at least one surface of the acrylic film using the water-based primer composition of claim 1.
11. The optical film of claim 10, wherein the primer layer has a thickness of 50 nm to 1000 nm.
12. The semiconductor device of claim 10, further comprising: an alignment layer formed on the primer layer; And a liquid crystal layer formed on the alignment layer.
13. The polarizing plate comprising the optical film of claim 10.
14. A display device comprising the polarizing plate of claim 13.

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