JP2014534988A - Aqueous composition, optical film including the same, polarizing plate using the same, and liquid crystal display device - Google Patents

Abstract

The present invention includes an aqueous primer composition containing 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, and the same. The present invention relates to an optical film, a polarizing plate using the same, and a liquid crystal display device. [Selection] Figure 2

Description

  The present invention relates to a water-based primer composition, an optical film including the same, a polarizing plate using the same, and a liquid crystal display device. More specifically, the present invention has excellent adhesiveness to an acrylic film, and the optical film can be applied to an optical film. The present invention relates to an optical film including an aqueous primer composition that does not impair optical properties and durability, a polarizing plate using the same, and a liquid crystal display device.

  2. Description of the Related Art A liquid crystal display (LCD) device is a display device that expresses pixels by using a principle of selectively allowing light to pass through a change in polarization action due to an arrangement of liquid crystals positioned between polarizing plates. When only a polarizing plate is applied to a liquid crystal display device without a separate optical film, there is a problem that brightness or contrast is significantly reduced or a light leakage phenomenon occurs when viewing the screen from the tilt direction. In order to solve such a 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. In this way, optical compensation films such as retardation films and viewing angle compensation films are inserted between the polarizing plate and the liquid crystal display element to reduce the hue change of the liquid crystal display (LCD) device and expand the viewing angle to improve the brightness. It is used for the purpose of making it.

  On the other hand, the above-mentioned optical compensation film is produced by applying a polymerized liquid crystal compound on a plastic substrate, drying it, and irradiating it with ultraviolet rays. It can be divided into liquid crystal films produced by curing.

  The stretched film and the liquid crystal film used as the optical film have optical anisotropy. At this time, the method for imparting optical anisotropy to the stretched film is usually a mixture ratio of a substance having a positive phase difference and a substance having a negative phase difference used in the production of the polymer film and the polymer film. This is done by adjusting the stretch ratio. The liquid crystal film is classified into a disc-type liquid crystal and a rod-type liquid crystal according to the shape of the liquid crystal molecules. Among them, in particular, the rod-like liquid crystal has various alignment forms such as planar, homeotropic, tilted, spread, and cholesteric. Therefore, the method of imparting optical anisotropy to the liquid crystal film is usually performed by adjusting the alignment form.

  On the other hand, as shown in FIG. 1, in the conventional liquid crystal film, after the alignment film 2 is formed on the TAC substrate 3, the alignment film is aligned by rubbing treatment or polarized irradiation, and the polymerizable film is polymerizable thereon. The liquid crystal compound was applied, dried and cured, and fixed to form the liquid crystal layer 1. However, in this case, due to the fragility of the film of the TAC component with respect to moisture, a problem of durability due to dimensional change occurs during long-term use.

  In order to compensate for these disadvantages, a film having a composition having a high resistance to moisture and low retardation properties, such as a cycloolefin resin or an acrylic resin, is applied to the liquid crystal film. Attempts have been made. In particular, an acrylic composition film is known to have advantages in terms of cost as well as optical characteristics and durability. However, in the case of an acrylic film, unlike a triacetyl cellulose (TAC) base material, a high stretch ratio results in low surface roughness (roughness), and the surface is dense and difficult to penetrate the coating layer. There is a problem that adhesion between the acrylic film and the alignment film and the liquid crystal layer is not good. In addition, in the case of an acrylic film, since the solvent resistance is poor, there is also a problem that the acrylic film is damaged by the organic solvent contained in the alignment film composition and the alignment characteristics do not appear well.

  Therefore, even if an acrylic film is used as a base film, the development of a technique capable of producing an optical film having excellent adhesion with an alignment film and a liquid crystal layer, excellent solvent resistance, and excellent alignment characteristics is urgently required. ing.

  The present invention is for solving the above-described problems, and an aqueous primer composition capable of improving the solvent resistance of an acrylic film and the adhesion to an alignment film, an optical film including the same, It is an object of the present invention to provide a polarizing plate and a liquid crystal display device using the above.

  In order to solve the above problems, according to the first aspect of the present invention, 100 parts by weight of 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 And an aqueous primer composition comprising:

  At this time, the solid content of the aqueous primer composition is preferably about 1 to 50 parts by weight with respect to 100 parts by weight of the entire aqueous primer composition. In the water-based primer composition, the urethane resin preferably has a weight average molecular weight of 10,000 to 200,000 and contains a carboxyl group. Moreover, the said urethane resin can be obtained by making a polyol and isocyanate react.

  According to the 2nd aspect of this invention, the optical film containing the primer layer formed using the said water-system primer composition is provided.

  According to the 3rd aspect of this invention, the polarizing plate containing the said optical film is provided.

  According to the 4th aspect of this invention, the display apparatus containing the said polarizing plate is provided.

  An acrylic film including a primer layer formed using the water-based primer composition of the present invention is extremely excellent in adhesion to an alignment film and solvent resistance, and therefore is useful as a base film for a liquid crystal film. Can do.

  In addition, when the above-mentioned liquid crystal film is used as a polarizer protective film, the use of the water-based primer composition according to the present invention can provide excellent adhesion between the polarizer and the acrylic film. In addition, the optical properties such as the light transmittance of the polarizing plate are not impaired, and the durability can be improved.

It is the figure which showed the structure of the conventional optical film. It is the figure which showed the structure of the optical film by an example of this invention.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, the embodiments of the present invention can 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 fully explain the present invention to those skilled in the art. Accordingly, the shape and size of elements in the drawings may be exaggerated for a clearer description.

  According to the first aspect of the present invention, an aqueous system 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 remaining water. A primer composition is provided. In addition, in this specification, the content of the said urethane resin, polyvinyl alcohol, and water dispersible fine particles means solid content.

  In the present specification, the “remainder” means the remaining amount excluding the content of urethane resin, polyvinyl alcohol, water-dispersible fine particles and selectively contained components when the total content of the water-based primer composition is 100 parts by weight. It means parts by weight. That is, it means that after adding the urethane resin, polyvinyl alcohol, water-dispersible fine particles and selectively contained components and adding water, the total content of the aqueous primer composition is adjusted to 100.

  The aqueous primer composition of the present invention is preferably water-soluble in that it does not require the 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 are advantages in that the adhesive strength is excellent and the urethane synthesis is easy.

  Moreover, it is preferable that the said urethane resin is obtained by making a polyol and isocyanate react.

  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 can be used. For example, one or more selected from the group consisting of polyester polyol, polyether polyol, polycarbonate diol and the like can be used in combination, but is not limited thereto.

  In the water-based primer composition of the present invention, among the examples of the polyol for obtaining the urethane resin, the polyester polyol is preferably obtained by reacting a polybasic acid component and a polyol component.

  Here, as the polybasic acid component for obtaining the polyester polyol, ortho-phthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, Aromatic dicarboxylic acids such as 2,6-naphthalenedicarboxylic acid, biphenyldicarboxylic acid, tetrahydrophthalic acid, oxalic acid, oxalic acid, malonic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacin Aliphatic dicarboxylic acids such as acid, linolenic acid, maleic acid, fumaric acid, mesaconic acid, itaconic acid, hexahydrophthalic acid, tetrahydrophthalic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid Alicyclic dicarboxylic acids such as these, or these acids Anhydride, alkyl esters, may be used in combination of one or more selected from the group consisting of reactive derivatives such as acid halides, but are not limited thereto.

  The polyol component for obtaining the polyester polyol includes ethylene glycol, 1,2-propanone diol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, Pentanediol, 1,6-hexanediol, 1,8-octanediol, 1-10-decanediol, 4,4'-dihydroxyphenylpropane, 4,4'-dihydroxymethylmethane, diethylene glycol, triethylene glycol, polyethylene glycol , Dipropylene glycol, polypropylene glycol, 1,4-cyclohexanedimethanol, 1,4-cyclohexanediol, bisphenol A, bisphenol F, glycerin, 1,1,1-trimethylolpropane, 1,2,5- Kisatorioru, pentaerythriol, glucose, it can be one selected from the group consisting of sucrose and sorbitol, but are not limited thereto.

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

  In the water-based primer composition of the present invention, among the polyols for obtaining the urethane resin, the polycarbonate polyol is one selected from the group consisting of poly (hexamethylene carbonate) glycol and poly (cyclohexane carbonate) glycol. However, it is not limited to this.

  On the other hand, as the isocyanate, toluene diisocyanate (TDI), 4,4-diphenylmethane diisocyanate (MDI), 1,5-naphthalene diisocyanate (NDI), tolidine diisocyanate (TODI), hexamethylene diisocyanate (HMDI), isophorone diisocyanate (IPDI). ), P-phenylene diisocyanate, 1,4-diisocyanate and xylene diisocyanate (XDI) can be used in combination, but is not limited thereto.

  In the water-based primer composition according to the present invention, the urethane resin preferably contains a carboxyl group. Here, the carboxyl group plays a role of improving the adhesion with the polarizer by forming an anion portion and dispersing it in water when producing water-dispersed urethane.

  The urethane resin containing a carboxyl group as described above is obtained by reacting the polyol and the isocyanate with a chain extender having a glass carboxyl group. At this time, 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 includes at least one kind from the group consisting of dialkyrol alkanoic acids such as dimethylolalkanoic acid (dimethylolacetic acid, dimethylolbutanoic acid, dimethylolpropionic acid, dimethylolbutyric acid, and dimethylolpentanoic acid). Although it can be used in combination, it is not limited to this.

  On the other hand, any appropriate method can be used as a method for producing the urethane resin. For example, a one-shot method in which each of the above components is reacted at once, a multistage method in which the components are reacted stepwise, and the like can be mentioned. When the urethane resin has a carboxyl group, it is preferably produced by a multistage method in order to easily introduce the carboxyl group. In addition, any appropriate urethane reaction catalyst can be used during the production of the urethane resin.

  In the production of the urethane resin, other polyols and other chain extenders may be added to the above components, or these may be reacted in combination.

  In this case, the other polyol is not particularly limited as long as it has 3 or more hydroxyl groups, and may be, for example, sorbitol, glycerin, trimethylolethane, trimethylolpropane, or pentaerythritol.

  The other chain extenders include, for example, ethylene glycol, diethylene glycol, triethylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, , 6-hexanediol, glycols such as propylene glycol, ethylenediamine, propylenediamine, hexamethylenediamine, 1,4-butanediamine, aliphatic diamines such as aminoethylethanolamine, isophoronediamine, 4,4'-dicyclohexylmethanediamine The aromatic diamines such as alicyclic diamines such as xylylenediamine and tolylenediamine, and the like are not limited thereto.

  On the other hand, during the production of the urethane resin, a neutralizing agent can be used to improve the stability of the urethane resin in water. Examples of the neutralizing agent include one or more selected from the group consisting of ammonia N-methylmorpholine, triethylamine, dimethylethanolamine, methyldiethanolamine, triethanolalkyne, morpholine, tripropylamine, ethanolamine, and triisopropanolamine. Can be used in combination, but is not limited thereto.

  Moreover, it is preferable to use the organic solvent which is inactive with respect to the isocyanate and is compatible with water during the production of the urethane resin. In this case, the organic solvent is one selected from the group consisting of ester solvents such as ethyl acetate and ethyl cellosolve acetate, ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone, and ether solvents such as dioxane tetrahydrofuran. The above can be used in combination, but is not limited thereto.

  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, the solvent resistance is improved and the viscosity does not increase, so that coating and drying are easy.

  The content of the polyvinyl alcohol may be 1 to 100 parts by weight, preferably 10 to 100 parts by weight, and more preferably 50 to 100 parts by weight with respect to 100 parts by weight of the urethane resin. . When the content of the polyvinyl alcohol satisfies the above numerical range, the solvent resistance is improved, the adhesion with the acrylic is improved, and the content of the polyvinyl alcohol does not increase, so the viscosity is constant and leveling is easy during coating. is there.

On the other hand, the polyvinyl alcohol is for improving solvent resistance, and is not particularly limited as long as it is usually used in the technical field. Examples of the polyvinyl alcohol include Gohsheimer Z-100 ^(r) , Z-200 ^(r) , Z-200H ^(r) , Z-210 ^(r) , Z-220 ^(r) manufactured by Nippon Synthetic Chemical Co., Ltd. Z-320 ^(r) or the like can be used.

  As the fine particles that can be used in the present invention, any appropriate fine particles, preferably water-dispersible fine particles, can be used. Specifically, inorganic fine particles and / or organic fine particles can be used.

  Here, the inorganic fine particles may be inorganic oxides such as silica, titania, alumina, zirconia, or antimony, but are not limited thereto. 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 are not limited thereto.

  In particular, in the water-based primer composition according to the present invention, the water-dispersible fine particles are preferably silica. The silica is superior in blocking suppression ability, has excellent transparency, does not generate haze, and is not colored, and thus has an advantage of having 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, it is excellent in workability when forming the primer layer.

  On the other hand, the average diameter, that is, the primary average particle diameter of the water-dispersible fine particles may be, for example, 10 nm to 200 nm, 15 nm to 150 nm, or 20 nm to 100 nm. When the average diameter of the water-dispersible fine particles satisfies the above numerical range, the agglomeration and precipitation rate of the water-dispersible particles in the water-based primer solution is reduced, resulting in excellent solution stability and water-dispersibility in the water-based primer solution. Since the particles can be uniformly dispersed and the particles can be prevented from aggregating, it is possible to prevent haze from being increased by scattering light in the visible light region.

  That is, by using water-dispersible fine particles having a particle size in the above range, irregularities can be appropriately formed on the surface of the primer layer. In particular, the contact surface between the acrylic film and the primer layer and / or Or the frictional force in the contact surface of primer layers can be reduced effectively. As a result, when the film on which the primer layer is formed is wound, it is more excellent in blocking inhibition ability.

  Since the primer composition of the present invention is aqueous, the water-dispersible fine particles are preferably formulated as an aqueous dispersion. More specifically, when silica is used as the water-dispersible fine particles, it is preferably blended as colloidal silica. As the colloidal silica, products commercially available in the technical field can be used as they are. For example, the Snowtex series manufactured by Nissan Chemical Industries, the AEROSIL series manufactured by Air Products, the epostar series manufactured by Nippon Shokubai, and the soliostar The RA series or the LSH series manufactured by Ranco can be used.

  At this time, the content of the water dispersible fine particles may be 0.1 to 10 parts by weight or 0.1 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 above numerical range, the blocking occurrence rate is remarkably reduced, the haze is reduced, and a film having excellent optical properties can be obtained.

  In the water-based primer composition of the present invention, the solid content is not particularly limited. However, the solid content is, for example, 1 to 50 parts by weight, preferably 5 to 30 parts by weight, and more preferably 10 to 20 parts by weight with respect to 100 parts by weight of the aqueous primer composition. be able to. When the solid content in the water-based primer composition according to the present invention satisfies the above numerical range, the adhesiveness is improved and the viscosity is not high. Therefore, there are advantages in that leveling is good during coating and drying time is short. At this time, the solid content means the solid content of the entire aqueous primer composition.

  According to the 2nd aspect of this invention, the optical film containing the primer layer formed using the said water-system primer composition in the at least 1 surface of an acrylic film is provided.

  In the present invention, an optical film is a general term for a film that performs an optical function, and not only a transparent film having a light transmittance of 80% or more but also a specific optical function such as a polarizing plate. In the case of this film, an optical film having a light transmittance of 50% or less is also included.

  The acrylic film that can be used in the present invention may have a single layer structure or a structure in which two or more layers are laminated.

  More specifically, the acrylic film can contain a (meth) acrylate resin. Under the present circumstances, the film containing (meth) acrylate type resin is obtained by shape | molding the molding material which contains (meth) acrylate type resin as a main component by an extrusion molding method, for example.

  The (meth) acrylate-based resin is mainly composed of a resin containing a (meth) acrylate-based unit, and includes not only a homopolymer resin composed of a (meth) acrylate-based unit, but also a (meth) acrylate-based unit. In addition, a copolymer resin obtained by copolymerizing other monomer units and a blend resin obtained by blending another resin with the (meth) acrylate resin as described above are also included.

  At this time, the (meth) acrylate unit may be, for example, an alkyl (meth) acrylate unit. Here, the alkyl (meth) acrylate unit means all alkyl acrylate units and alkyl methacrylate units, and the alkyl group of the alkyl (meth) acrylate units has 1 to 10 carbon atoms. It is preferable that it has 1 to 4 carbon atoms.

  On the other hand, monomer units that can be copolymerized with the above (meth) acrylate units include aromatic vinyl units, 3- to 6-membered heterocyclic units substituted with carbonyl groups, acrylic acid units, and glycidyl units. Etc.

  Examples of the aromatic vinyl-based unit include 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-tert-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-dic Group consisting of low styrene, octachlorostyrene, 2-bromostyrene, 3-bromostyrene, 4-bromostyrene, 2,4-dibromostyrene, α-bromostyrene, β-bromostyrene, 2-hydroxystyrene and 4-hydroxystyrene The unit may be derived from one or more monomers selected from, but is not limited thereto. Among these, a unit derived from styrene or α-methylstyrene is particularly preferable.

  Meanwhile, the 3- to 6-membered heterocyclic unit substituted with the carbonyl group is a unit derived from a monomer such as a lactone ring, glutaric anhydride, glutarimide, maleic anhydride, maleimide or the like. Can be.

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

  On the other hand, the method for producing the (meth) acrylate-based resin film is not particularly limited. For example, the (meth) acrylate-based resin, other polymers, additives, and the like are sufficiently mixed by any appropriate mixing method. A method for producing a thermoplastic resin composition after film formation, or (meth) acrylate resin and other polymers produced as separate solutions and additives are mixed uniformly. A method of forming a liquid and then forming it into a film can be used.

  Under the present circumstances, the said thermoplastic resin composition is manufactured by extruding and kneading the mixture obtained after pre-blending the raw material of the said film with arbitrary appropriate mixers, such as an omni mixer, for example. In this case, the mixer used for extrusion kneading is not particularly limited. For example, any suitable mixer such as an extruder such as a short screw extruder or a twin screw extruder or a pressure kneader can be used. .

  Examples of the film forming method include any suitable film forming method such as a solution casting method (solution casting method), a melt extrusion method, a calendar method, or a compression molding method. Among these film forming methods, the solution casting method (solution casting method) or the melt extrusion method is preferable.

  At this time, examples of the solvent used in the solution casting method (solution casting method) include aromatic hydrocarbons such as benzene, toluene, and xylene, aliphatic hydrocarbons such as cyclohexane and decalin, ethyl acetate, and acetic acid. Esters such as butyl, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methanol, ethanol, isopropanol, butanol, isobutanol, methyl cellosolve, ethyl cellosolve, alcohol such as butyl cellosolve, ethers such as tetrahydrofuran, dioxane, dichloromethane , Halogenated hydrocarbons such as chloroform and carbon tetrachloride, dimethylformamide, dimethyl sulfoxide and the like. These solvents may be used alone or in combination of two or more.

  Examples of the apparatus for performing the solution casting method (solution casting method) include a drum type casting machine, a band type casting machine, and a spin coater. Examples of the melt extrusion method include a T-die method and an inflation method. The molding temperature is preferably 150 to 350 ° C, more preferably 200 to 300 ° C.

  At this time, when the film is formed by the T-die method, a T-die is attached to the tip of a known short-axis extruder or twin-screw extruder, and the film extruded into a roll is wound up. Film can be obtained. At this time, uniaxial stretching can be performed by appropriately adjusting the temperature of the winding roll and adding stretching in the extrusion direction. Also, simultaneous biaxial stretching, sequential biaxial stretching, and the like can be performed by stretching the film in a direction perpendicular to the extrusion direction.

  On the other hand, the acrylic film may be either an unstretched film or a stretched film. In the case of a stretched film, it may be a uniaxially stretched film or a biaxially stretched film, and in the case of a biaxially stretched film, either a simultaneous biaxially stretched film or a sequential biaxially stretched film may be used. In the case of biaxial stretching, the mechanical strength is improved and the film performance is improved. The acrylic film can maintain optical isotropy by suppressing an increase in retardation even when stretched, by mixing other thermoplastic resins.

  In this case, the stretching temperature is preferably in the vicinity of the glass transition temperature of the thermoplastic resin composition that is the raw material of the film, and within the range of (glass transition temperature-30 ° C.) to (glass transition temperature + 100 ° C.). More preferably, it is more preferably in the range of (glass transition temperature−20 ° C.) to (glass transition temperature + 80 ° C.). When the stretching temperature is lower than (glass transition temperature-30 ° C.), there is a possibility that a sufficient stretching ratio cannot be obtained. On the other hand, when the stretching temperature exceeds (glass transition temperature + 100 ° C.), the resin composition flows, so there is a possibility that stable stretching cannot be performed.

  The draw ratio defined by the area ratio is preferably 1.1 to 25 times, more preferably 1.3 to 10 times. When the draw ratio is less than 1.1 times, there is a possibility that the toughness accompanying the drawing will not be improved. When the draw ratio exceeds 25 times, there is a possibility that the effect corresponding to the increase of the draw ratio may not be achieved.

  Furthermore, the stretching speed is preferably 10 to 20,000% / min, more preferably 100 to 10,000% / min in one direction. When the stretching speed is less than 10% / min, a long time is required to obtain a sufficient stretching ratio, which may increase the manufacturing cost. When the stretching speed exceeds 20,000% / min, the stretched film may be broken.

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

  If necessary, the acrylic film can be subjected to a surface treatment for improving the adhesive force. For example, at least one surface treatment selected from the group consisting of alkali treatment, corona treatment, and plasma treatment can be applied to at least one surface of the acrylic film.

  On the other hand, the primer layer is formed of the above-described aqueous primer composition of the present invention, and can be formed by a method of applying the aqueous primer composition to at least one surface of the acrylic film. . Since the specific content regarding the said water-system primer composition is the same as the content mentioned above, the specific description is abbreviate | omitted.

  On the other hand, the primer layer is not particularly limited in its forming method, and can be formed by a coating layer forming method usually used in the art, such as wire coating, bar coating, spin coating, and the like.

  On the other hand, in the optical film of the present invention, the primer layer may be formed only on one surface of the acrylic film or on both surfaces. According to the studies by the present inventors, the water-based primer composition of the present invention has a function of improving the adhesion between the alignment film and the acrylic film and also improving the adhesion between the polarizer and the acrylic film. Can do. Therefore, when the primer layer by the water-based primer composition of the present invention is formed on both surfaces of the acrylic film, the adhesive force between the polarizer and the acrylic film and the adhesive force between the acrylic film and the alignment film can all be improved. it can.

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

  At this time, the alignment film layer is rubbed after a variety of alignment film compositions well known in the art, for example, a photo alignment film composition or a rubbing alignment film composition is applied on the primer layer. It can be formed by orientation by treatment or polarized light irradiation treatment. The alignment film composition and alignment film forming method that can be used in the present invention are not particularly limited, and various types can be used as long as they are well known in the art.

  At this time, as a method for applying the alignment film composition, a method well known in the art, for example, a method such as wire coating, bar coating, spin coating, or the like can be used.

  In addition, after applying the alignment film composition, a drying process for removing the residual solvent may be performed. At this time, the drying may be performed at 70 ° C. to 150 ° C. for at least 30 seconds. The drying temperature and time are not particularly limited, but when the above conditions are satisfied, the alignment film can be sufficiently dried without deformation of the substrate.

  On the other hand, for the above-mentioned alignment treatment, a method such as rubbing alignment or photo-alignment can be used as appropriate depending on the type of alignment film used. In order to improve the alignment, all rubbing alignment and photo-alignment are performed as necessary. It can also be used. At this time, the rubbing alignment is performed by a method such as rubbing the surface of the alignment film with a cloth, and the photo-alignment is performed by irradiating polarized ultraviolet rays through a polarizing plate or the like between the alignment film and the light source. Can be done. At this time, the irradiation with the ultraviolet rays can be performed in the air or in a nitrogen atmosphere in which oxygen is blocked to increase the reaction efficiency. Usually, at the time of ultraviolet irradiation, an intermediate or high pressure mercury ultraviolet lamp having a strength of 80 w / cm or more, or a metal halide lamp is used.

  On the other hand, in the present invention, the alignment film composition is not particularly limited, and an alignment film composition containing a photoreactive polymer, a polyfunctional monomer, an initiator, and a solvent can be used. May further include a cross-linking agent, if necessary. More specifically, the alignment film composition of the present invention is not particularly limited, and 0.05 parts by weight to 10 parts by weight of a polyfunctional monomer and photoreaction with respect to 100 parts by weight of the alignment film composition. 0.05 part by weight to 10 parts by weight of the polymer, 0.01 part by weight to 5 parts by weight of the photoinitiator, and the balance of the solvent, and optionally 0.01 part by weight of the crosslinking agent. Part to 2 parts by weight can be further included.

  As the polyfunctional monomer, a mixed polyfunctional monomer that is a mixture of a polyfunctional triazine monomer and a polyfunctional acrylic monomer can be used. In the mixed polyfunctional monomer of the polyfunctional triazine monomer and the polyfunctional acrylic monomer, the mixing ratio of the triazine monomer and the acrylic monomer is not particularly limited. If both a triazine monomer and an acrylic monomer can be used, a mixed polyfunctional monomer in which these two components are mixed at an arbitrary ratio can be used.

  Examples of the polyfunctional triazine monomers include 1,3,5-triallyl-1,3,5-triazinene-2,4,6-trione and 1,3,5-triacryloyl-1. , 3,5-triazinene, 1,3,5-tris (2-oxiranylmethyl) -1,3,5-triazinene-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-5- (2-cyano-ethyl) -2 , 4,6-trioxo- (1,3,5) triazinan-1-yl) -propionitrile can be used, but is not limited thereto.

  Further, examples of the polyfunctional acrylic monomer include triacrylate (particularly pentaerythritol triacrylate (PENTAerythritol triacrylate), PETA), tetraacrylate (particularly pentaerythritol tetraacrylate (particularly pentaerythritol tetraacrylate). ), PETTA) and hexaacrylate (especially dipentaerythritol hexaacrylate, DPHA), but not limited thereto. Meanwhile, the content of the functional monomer to be mixed may be 0.05 to 10 parts by weight based on the photo-alignment film composition. When the content of the polyfunctional acrylic monomer satisfies the above numerical range, it is excellent in interlayer adhesion between the photo-alignment film and the base film, thus preventing the problem of peeling off the photo-alignment film and excellent orientation Can be realized.

  On the other hand, the photoreactive polymer can be, for example, a norbornene-based photoreactive polymer containing a cinnamate group. In this case, the norbornene-based photoreactive polymer containing the cinnamate group includes, for example, polynorbornene cinnamate, polynorbornene alkoxycinnamate (the alkoxy group has 1 to 20 carbon atoms), polynorbornene aryloyloxycinnamate, and polynorbornene. Including, but not limited to, one or more selected from the group consisting of fluorinated cinnamate, polynorbornene chlorinated cinnamate and polynorbornene dicinnamate. Furthermore, 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 photo-alignment film composition. . When the content of the photoreactive polymer satisfies the above numerical range, a photoalignment film having excellent orientation can be obtained.

  The photoinitiator may be any as long as it can induce a radical reaction, but is preferably water-soluble. For example, Irgacure 2959 (IRGACURE2959, 2-Hydroxy-1-phenyl) -2-methyl-1-propanone, Irgacure 500 (IRGACURE500, IRGACURE500, manufactured by Ciba-Geigy) -Cyclohexyl-phenyl-ketone + Benzophenone), Irgacure 754 (IRGACURE754, oxyphenyl-acetic acid2- [2oxo-2phenyl-acetoxy-ethy-ethy-ethy-2] IRGACURE OXE02,1- (1-6-benzoyl-9-ethyl-9H-carbazol-3-yl) ethylideneaminooxy) but can be ethanone etc., not limited thereto. Meanwhile, the content of the photoinitiator may be 0.01 to 5 parts by weight based on the photoalignment film composition. When the content of the photoinitiator satisfies the above numerical range, a crosslinking reaction effect by the polyfunctional monomer is brought about, and the orientation of the liquid crystal is increased.

  On the other hand, the solvent may be any solvent as long as it can dissolve the polyfunctional monomer and the photoreactive polymer, and there is no particular limitation on the type thereof. Examples of the solvent include halogenated hydrocarbons such as chloroform, tetrachloroethane, trichloroethylene, tetrachloroethylene, and chlorobenzene, aromatic hydrocarbons such as benzene, toluene, xylene, methoxybenzene, and 1,2-dimethoxybenzene, acetone, Organic solvents such as ketones such as methyl ethyl ketone, cyclohexanone and cyclopentanone, alcohols such as isopropyl alcohol and n-butanol, cellosolves such as methyl cellosolve, ethyl cellosolve and butyl cellosolve, water, or a mixture thereof can be used.

  Meanwhile, as the cross-linking agent, aldehydes, dialdehydes, isocyanates, and the like can be used, but are not limited thereto. Here, the aldehydes or dialdehydes may be, for example, acrylic aldehyde, oxalaldehyde, 2-methylacrylaldehyde, 2-oxopropanal, glutaraldehyde, or the like, but are not limited thereto. The isocyanate may be, for example, 2-isocyanatoethyl 2-methyl acrylate, 1,4-diisocyanatobutane, 1,4-diisocyanate benzene or 1,3-diisocyanate benzene. Yes, but not limited to this. The said crosslinking agent may be used independently and may be used as a 2 or more types of mixture.

  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 whole alignment film composition. When the content of the crosslinking agent satisfies the above numerical range, a sufficient crosslinking reaction can be induced. Therefore, the moisture resistance is excellent, the solution stability is excellent, and the uniform coating property is maintained. Excellent liquid crystal alignment.

  The liquid crystal layer can be formed by a method for forming a liquid crystal layer well known in the art, for example, a method in which a liquid crystal compound solution is applied onto an alignment layer that has been subjected to an alignment treatment and then fixed. .

  At this time, the liquid crystal compound solution can be applied by a general method well known in the art, for example, a method such as wire coating, bar coating, spin coating, or the like.

  In addition, after applying the liquid crystal compound solution, a drying process may be performed to remove the residual solvent. At this time, the drying may be performed at 25 ° C. to 120 ° C. for at least 1 minute. The drying temperature and time are not particularly limited, but the above drying conditions are preferably satisfied from the viewpoint of improving the degree of alignment of liquid crystals and preventing the occurrence of defects.

  On the other hand, the fixing is for fixing the liquid crystal alignment, and can be performed, for example, by polymerizing and curing the liquid crystal compound by irradiation with ultraviolet rays. At this time, the irradiation with the ultraviolet rays can be performed in the air or in a nitrogen atmosphere in which oxygen is blocked to increase the reaction efficiency. Usually, as the ultraviolet irradiator, an intermediate pressure or high pressure mercury ultraviolet lamp having a strength of 80 w / cm or more, or a metal halide lamp is used. A cold mirror or other cooling device may be installed between the base material and the ultraviolet lamp so that the surface temperature of the liquid crystal layer is within the temperature range that maintains the liquid crystal state when irradiated with ultraviolet rays.

  On the other hand, as the liquid crystal compound solution, a liquid crystal compound solution usually used in the technical field can be used without limitation. For example, a liquid crystal compound solution produced by dissolving the polymerizable liquid crystal compound and the photoinitiator in an organic solvent can be used.

  In this case, as the polymerizable liquid crystal compound, a substance having an acrylate group that can be polymerized by a photoreaction and well known in the art can be used without limitation. For example, a low-molecular liquid crystal substance that exhibits a nematic or cholesteric liquid crystal phase at room temperature or high temperature, such as cyanobiphenyl, cyanophenylcyclohexane, cyanophenyl ester, benzoic acid phenyl ester, or phenylpyrimidine acrylate, alone or 2 It can be used as a mixture of seeds or more. The content of the polymerizable liquid crystal compound in the liquid crystal compound solution is not particularly limited, and may be 5 to 70 parts by weight, preferably 5 to 50 parts by weight with respect to 100 parts by weight of the liquid crystal compound solution. . When the content of the polymerizable liquid crystal compound satisfies the above numerical range, the occurrence of unevenness is remarkably reduced, and the problem that the polymerizable liquid crystal compound is precipitated due to an insufficient amount of the solvent can be prevented.

  The photoinitiator is not particularly limited as long as it is well known in the technical field, and for example, Irgacure 907 (IRGACURE907) or the like can be used. On the other hand, the content of the photoinitiator is preferably about 3 to 10 parts by weight with respect to 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 above numerical range, sufficient curing by irradiation with ultraviolet rays is possible, and it is possible to prevent the liquid crystal alignment from changing due to the influence of the photoinitiator.

  In addition to the photoinitiator, a chiral agent, a surfactant, a polymerizable monomer, a polymer, or the like is added to the liquid crystal compound solution as needed as long as it does not interfere with liquid crystal alignment. be able to.

  On the other hand, the organic solvent used for the production of the liquid crystal compound solution is not particularly limited. For example, halogenated hydrocarbons such as chloroform, tetrachloroethane, trichloroethylene, tetrachloroethylene, chlorobenzene, benzene, toluene, xylene, methoxybenzene, Aromatic hydrocarbons such as 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. These can be used alone or as a mixture of two or more.

  According to the 3rd aspect of this invention, the polarizing plate containing the said optical film by this invention is provided. The polarizing plate of the present invention can comprise, 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 can 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 laminated on at least one surface of a polarizer.

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

  According to the 4th aspect of this invention, the display apparatus containing the said polarizing plate is provided.

  The display device includes a liquid crystal display element and the like, but there is no limitation on the type of the display device as long as it requires the optical film or polarizing plate as described above. The display device has a configuration known in the art except that it includes a primer layer formed using the aqueous primer composition according to the present invention. For example, the display element may be a liquid crystal display element including a liquid crystal cell and a polarizing plate and a backlight unit according to the present invention provided on both surfaces of the liquid crystal cell.

Example 1
50 g of urethane resin emulsion (CK-PUD-F (Chokwang-poly urethane dispersion) solid content 10% emulsion), polyvinyl alcohol aqueous solution (Nippon Gosei Chemical, Z200, 4.5% solid content aqueous solution) 111 g, colloidal silica (Ranco, 20% solid aqueous solution) was mixed with 0.5 g to produce a water-based primer composition having a solid content ratio of urethane resin to polyvinyl alcohol of 1: 1. After that, the above water-based primer composition was coated on a corona-treated acrylic film (LG Chemical Company, GP-film) at a thickness of about 1000 nm with # 9 bar, and then dried at 100 ° C. for 5 minutes to prepare a primer. An acrylic film having a layer formed thereon was produced.

  Next, 5-norbornene-2-methyl- (4-methoxycinnamate), a photoreactive polymer, dipentaerythritol hexaacrylate, a polyfunctional monomer, and Irgacure OXE02 (Switzerland, Switzerland) Ciba-Geigy) 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 photoalignment film composition.

  Next, the photo-alignment film composition was applied on the primer layer of the acrylic film with a wire bar so that the thickness after drying was 100 nm, and then dried with hot air in a drying oven at 70 ° C. for 2 minutes. Next, a wire grid polarizing plate made by Maxtek is interposed between the light source and the alignment film so that polarized ultraviolet rays are emitted, and once at a speed of 3 m / min using a high-pressure mercury lamp with an intensity of 80 w / cm as the light source. The alignment treatment was performed by exposure. The alignment film was completed by applying a rubbing treatment in order to impart alignment to the surface of the cured alignment film.

  Next, 95 parts by weight of a planar alignment liquid crystal mixture for A-PLATE (a planar alignment liquid crystal mixture composed of Merck, cyanobiphenyl, cyanophenylcyclohexane, and cyanophenyl ester acrylate) on the alignment film, and photoinitiation Polymeric liquid crystal compound solution prepared by dissolving solids mixed with 5 parts by weight of Irgacure 907 (Ciba-Geigy, Switzerland) as an agent in 25 parts by weight with respect to 100 parts by weight of the total solution. Is coated on the alignment film so that the thickness after drying is 1 μm, dried with hot air in a drying oven at 60 ° C. for 2 minutes, and then applied with non-polarized ultraviolet rays using a high-pressure mercury lamp having an intensity of 80 w / cm. Irradiated and cured to form a liquid crystal layer.

Example 2
An optical film was prepared in the same manner as in Example 1 except that the water-based primer composition was coated with a # 5 bar at a thickness of about 500 nm.

Example 3
An optical film was prepared in the same manner as in Example 1 except that the water-based primer composition was coated with a # 3 bar with a thickness of about 200 nm.

Example 4
An optical film was produced in the same manner as in Example 1 except that the primer layer was formed using an aqueous primer composition adjusted so that the solid content ratio of the urethane resin and polyvinyl alcohol was 1: 0.5.

Example 5
An optical film was produced in the same manner as in Example 1 except that the primer layer was formed using an aqueous primer composition adjusted so that the solid content ratio of the urethane resin and polyvinyl alcohol was 1: 0.1.

Comparative Example 1
An optical film was produced in the same manner as in Example 1 except that the primer layer was formed using an aqueous primer composition not containing polyvinyl alcohol.

Comparative Example 2
An optical film was produced 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 produced in the same manner as in Example 1 except that the primer layer was formed using an aqueous primer composition adjusted so that the solid content ratio of the urethane resin and polyvinyl alcohol was 1: 4.

Experimental example Adhesive strength The adhesive strength between the acrylic base material and the alignment film and the adhesive strength between the alignment film and the liquid crystal film were evaluated by a cross-cut test method defined by ASTM. After cross-cutting the surface of the liquid crystal film with a knife into a grid pattern at intervals of 1 mm, it is judged whether it is attached when cellophane tape is peeled off and the result is shown below. It showed in Table 1. The case where it was completely attached was indicated by O, and the case where it was partially or completely peeled was indicated by X.

2. Orientation The orientation of the liquid crystal layer formed on the photo-alignment film was visually confirmed, and the results are shown in Table 1. The case where it was not oriented was indicated by x, and the case where it was oriented with some deviation was indicated by ○.

  Although the embodiment of the present invention has been described in detail above, the scope of the right of the present invention is not limited to this, and various modifications and modifications can be made without departing from the technical idea of the present invention described in the claims. It will be apparent to those skilled in the art that variations are possible.

1 liquid crystal layer 2 alignment film 3 TAC film 4 primer 5 acrylic film

Claims (14)

100 parts by weight of urethane resin,
1 to 100 parts by weight of polyvinyl alcohol;
0.1 to 10 parts by weight of water-dispersible fine particles,
With the rest of the water,
An aqueous primer composition comprising:   The water-based primer composition of Claim 1 whose solid content is 1-50 weight part with respect to 100 weight part of said water-based primer compositions.   The water-based primer composition according to claim 1 or 2, wherein the urethane resin has a weight average molecular weight of 10,000 to 200,000.   The water-based primer composition according to any one of claims 1 to 3, wherein the urethane resin contains a carboxyl group.   The water-based primer composition according to any one of claims 1 to 4, wherein the urethane resin is obtained by reacting a polyol and an isocyanate.   The water-based primer composition according to any one of claims 1 to 5, wherein the polyvinyl alcohol has a weight average molecular weight of 2,000 to 40,000.   The water-based primer composition according to any one of claims 1 to 6, 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 fine particles. object.   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. The water-based primer composition according to any one of the above.   The water-based primer composition according to any one of claims 1 to 8, wherein the water-dispersible fine particles have an average diameter of 10 nm to 200 nm.   An optical film comprising a primer layer formed using the water-based primer composition according to any one of claims 1 to 9 on at least one surface of an acrylic film.   The optical film according to claim 10, wherein the primer layer has a thickness of 50 nm to 1000 nm. An alignment film layer formed on the primer layer;
A liquid crystal layer formed on the alignment layer;
The optical film according to claim 10 or 11, comprising:   A polarizing plate comprising the optical film according to claim 10.   A display device comprising the polarizing plate according to claim 13.

Images