WO2019203551A1 - Acrylic film having low water vapor transmittance, and polarizing plate and panel, which comprise same - Google Patents

Abstract

The present invention provides: an acrylic film manufactured, by a solvent casting method, from a main dope comprising a compound represented by the following chemical formula 1 and an acrylic resin, the acrylic film having an in-plane retardation Ro, measured under conditions of 23°C and 55%RH, of 0-5 nm, having an out-of-plane retardation Rth of -10 to -3 nm, and having a water vapor transmittance rate of 150 g/m^2·24h or less in a high-temperature high-humidity environment of 60°C and 90%RH; and a polarizing plate and a panel, which comprise the acrylic film. [Chemical formula 1] In chemical formula 1, R₁ is a substituted or unsubstituted ring-forming C6-50 aryl group, R₂ and R₃ are respectively and independently a hydrogen atom, a halogen atom, a hydroxyl group or a substituted or unsubstituted C1-12 alkyl group, m:n is 100:0 to 50:50, and the molecular weight is 130,000-200,000 g/mol.

Description

Low moisture-permeable acrylic film, polarizing plate and panel comprising the same

The present application is the Korean Patent Application No. 10-2018-0045893 dated April 20, 2018 and the Korean Patent Application No. 10-2018-0045899 dated April 20, 2018, the Korean Patent Application No. 10-2018-0045901 dated April 20, 2018 Claiming the benefit of priority based on the above, all contents disclosed in the literature of the relevant Korean patent application are included as part of this specification.

The present invention relates to a low moisture-permeable acrylic film having a phase difference controlled, a polarizing plate and a panel comprising the same.

Background Art In recent years, low power consumption, low voltage operation, and light weight and thin liquid crystal display devices have been widely used in information display devices such as mobile phones, portable information terminal computer monitors, and television sets. Such information display devices are required to be reliable under severe environments depending on the application. For example, a liquid crystal display device for a car navigation system may have a very high temperature and humidity in a vehicle in which it is placed, and the required temperature and humidity conditions are severe when compared to a normal television or personal computer monitor. And although a polarizing plate is used for a liquid crystal display device in order to enable the display, in the liquid crystal display device which requires such severe temperature and / or humidity conditions, it is calculated | required to have high durability also in the polarizing plate which comprises it.

The polarizing plate usually has a structure in which a transparent protective film is laminated on both surfaces or one side of a polarizing film made of a polyvinyl alcohol-based resin in which a dichroic dye is adsorbed and oriented. And conventionally, triacetyl cellulose (TAC) is widely used for this protective film, This protective film is adhere | attached with a polarizing film through the adhesive which consists of aqueous solution of polyvinyl alcohol-type resin. By the way, since the polarizing plate in which the protective film which consists of triacetyl cellulose was laminated | stacked has high water vapor transmission rate of triacetyl cellulose, when it uses for a long time in a high humidity heat environment, polarization performance may fall, or a protective film and a polarizing film may peel off. have. In order to solve such a problem, it was tried to use the (meth) acrylic-type resin film with low moisture permeability compared with a triacetyl cellulose film as a protective film of a polarizing plate.

Conventional acrylic protective films have been manufactured by melt casting, but have many advantages in terms of eco-friendliness such as thinning, mass production, and recycling of resins when manufactured by the solvent casting method. In the solvent casting method, the acrylic film is dissolved in a solvent and extruded by T-Die, and then the solvent is dried on the belt to make a film.The optimized particle is added to increase the impact strength and to secure the slip property for film transfer. The same process is possible. In addition, the added particles should not be dissolved or deformed in the solvent.

In addition, the liquid crystal display technology is classified into various modes according to the initial arrangement of the liquid crystal and the way in which the electric field is applied. Typically, TN (Twisted Nematic), VA (Vertical Alignment), IPS (In-Plane Switching), and FFS (Fringe) Field Switching) mode. VA mode must apply a retardation film to achieve a wide viewing angle, but IPS mode and FFS mode can realize a certain viewing angle without applying a retardation film. However, as TVs have become larger, demands for viewing angles for the IPS mode and the FFS mode have arisen, and application of a retardation film is indispensable.

Therefore, while the moisture resistance is required, acrylic is being expanded as a material of the retardation film, and most of the acrylic film is produced by melt extrusion method, which facilitates the film forming process when producing the acrylic protective film by the solvent casting method. In order to produce an acrylic film having a phase difference controlled, a polarizing plate and a panel including the same, an improvement in technology is required.

The present invention has been made to solve the above problems, to provide a low-moisture-permeable acrylic film produced by the solvent casting method, the phase difference is controlled.

In another aspect, the present invention is to provide a polarizing plate to which the low moisture-permeable acrylic film is applied.

And the present invention is to provide a panel with low moisture permeability, manufactured using a polarizing plate to which a low moisture-permeable acrylic film is applied.

In order to solve the above problems, in one embodiment of the present invention,

Acrylic resins comprising alkyl acrylate units excluding methyl methacrylate units and methyl methacrylate; And

It provides an acrylic film prepared by using the main dope liquid containing 1 to 20 parts by weight of the compound represented by the following formula (1).

[Formula 1]

In Formula 1, R ₁ is a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms,

R ₂ and R ₃ are each independently a hydrogen atom, a halogen atom, a hydroxy group, or a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, and the composition ratio of m and n is 100: 0 to 50:50 and the molecular weight is 130,000 g / mol to 200,000 g / mol.

According to a preferred embodiment of the present invention, the acrylic film may have an in-plane retardation Ro of 0 to 5 nm and a thickness direction retardation Rth of -10 to -3 nm measured under the conditions of 23 ° C. and 55% RH.

According to another suitable embodiment of the present invention, the acrylic film has a film thickness of 10 to 60㎛, the water vapor transmission rate of the film measured under the conditions of 60 ℃, 90% RH may be 150g / m ^{2 ·} 24h or less.

According to another suitable embodiment of the present invention, the compound may be represented by any one of the following formula (2).

[Formula 2]

[Formula 3]

[Formula 4]

In Chemical Formulas 2 to 4,

R is a hydrogen atom, a halogen atom, a hydroxyl group, a substituted or unsubstituted C1-C12 alkyl group, or a substituted or unsubstituted C6-C50 aryl group, and the composition ratio of m and n is 70:30 And a molecular weight is from 130,000 g / mol to 200,000 g / mol.

In order to solve the above problems, a low moisture-permeable polarizing plate according to another embodiment of the present invention includes a polarizer and a protective film disposed on one side or both sides of the polarizer, and the protective film includes methyl methacrylate unit and methyl methacrylate. It may be formed by a solvent casting method using an acrylic resin containing an alkyl acrylate unit except the main dope solution containing 1 to 20 parts by weight of the compound represented by the following formula (1).

[Formula 1]

In Formula 1, R ₁ is a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, and R ₂ and R ₃ are each independently a hydrogen atom, a halogen atom, a hydroxyl group, or a substituted or unsubstituted carbon number. It is an alkyl group of 1-12, the composition ratio of m and n is 100: 0-50: 50, and molecular weight is 130,000g / mol-200,000g / mol.

The protective film may have an in-plane retardation Ro of 0 to 5 nm and a thickness direction retardation Rth of -10 to -3 nm measured under the conditions of 23 ° C. and 55% RH.

The protective film has a film thickness of 10 to 60㎛, the moisture permeability of the film measured under the condition of 60 ℃, 90% RH may be 150g / m ² · 24h or less.

The compound may be represented by any one of the following Chemical Formulas 2 to 4.

[Formula 2]

[Formula 3]

[Formula 4]

In Chemical Formulas 2 to 4,

R is a hydrogen atom, a halogen atom, a hydroxy group, a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, and the composition ratio of m and n is 70:30 , Molecular weight is 130,000 g / mol to 200,000 g / mol.

In order to solve the above problems, a low moisture-permeable panel according to another embodiment of the present invention includes a liquid crystal cell and a polarizing plate disposed on one side or both sides of the liquid crystal cell, and the polarizing plate is disposed on one side or both sides of the polarizer and the polarizer. It includes a protective film, wherein the protective film is an acrylic resin comprising a methyl methacrylate unit and alkyl acrylate units other than methyl methacrylate; And a main dope solution containing 1 to 20 parts by weight of a compound represented by Formula 1 below, to form a film by a solvent casting method.

[Formula 1]

In Formula 1, R ₁ is a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms,

R ₂ and R ₃ are each independently a hydrogen atom, a halogen atom, a hydroxy group, or a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, and the composition ratio of m and n is 100: 0 to 50:50 and the molecular weight is 130,000 g / mol to 200,000 g / mol.

The protective film may have an in-plane retardation Ro of 0 to 5 nm and a thickness direction retardation Rth of -10 to -3 nm measured under the conditions of 23 ° C. and 55% RH.

The protective film has a film thickness of 10 to 60㎛, the moisture permeability of the film measured under the conditions of 60 ℃, 90% RH may be 150g / m ^{2 ·} 24h or less.

The compound may be represented by any one of the following Chemical Formulas 2 to 4.

[Formula 2]

[Formula 3]

[Formula 4]

In Chemical Formulas 2 to 4,

R is a hydrogen atom, a halogen atom, a hydroxy group, a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, and the composition ratio of m and n is 70:30 , Molecular weight is 130,000 g / mol to 200,000 g / mol.

The present invention can be produced by containing a compound represented by the formula (1) to produce a low-moisture-permeable acrylic film with a controlled phase difference, it is effective to remove the residual solvent by enabling a high temperature process by improving the heat resistance of the film.

In addition, the polarizing plate of the present invention may contain a compound represented by the formula (1) to produce a polarizing plate to which a low moisture-permeable acrylic film with a phase difference is adjusted,

By manufacturing a panel using the said polarizing plate, there exists an advantage that it is possible to manufacture the panel which is excellent in visibility and resistant to moisture.

EMBODIMENT OF THE INVENTION Hereinafter, although the best form for implementing this invention is demonstrated in detail, this invention is not limited to these.

When the inventors of the present invention have repeatedly studied to develop an acrylic film that is easy to form a film and transfer a film when manufacturing a thin acrylic film by a solvent casting method, the molecular weight of the acrylic resin is in the range of 300,000 to 2,500,000 g / mol, When forming a film by the acrylic resin containing a specific component, it discovers that the protective film which is easy to form and transfer can be obtained, and has completed this invention.

The acrylic film according to the present invention may be prepared using a main dope liquid containing an acrylic resin and a compound represented by the following Chemical Formula 1. In this case, the main dope liquid may further include an additive as necessary.

Moreover, the polarizing plate which concerns on this invention is a polarizer; And it may include a protective film disposed on one side or both sides of the polarizer. In this case, the protective film may be prepared using a main dope solution containing an acrylic resin and a compound represented by the following formula (1). The main dope liquid may further include an additive as necessary.

In addition, the panel according to the present invention is a liquid crystal cell; And a polarizing plate disposed on one side or both sides of the liquid crystal cell. At this time, the polarizing plate is a polarizer; And it may include a protective film disposed on one side or both sides of the polarizer. In this case, the protective film may be prepared using a main dope solution containing an acrylic resin and a compound represented by the following formula (1). The main dope liquid may further include an additive as necessary.

First, the acrylic resin of this invention is demonstrated.

Acrylic resin of the present invention is a copolymer resin consisting of methyl methacrylate units, alkyl acrylate units, each of the monomer units in the form of repeating units. The acrylic resin is preferably an acrylic resin in which a methyl methacrylate unit and a butyl methacrylate unit represented by the following Chemical Formula 5 are polymerized.

[Formula 5]

(a and b are each an integer of 1 or more)

70 to 96 parts by weight of methyl methacrylate unit and 4 to 30 alkyl acrylate units except methyl methacrylate, based on 100 parts by weight of acrylic resin in consideration of optical properties, transparency, compatibility, processability and productivity It is preferably made of parts by weight.

If the methyl methacrylate unit content is less than 70 parts by weight, the optical performance of the protective film is worse, and if it exceeds 96 parts by weight it is difficult to remove the residual solvent of the protective film.

In addition, it is preferable that content of the alkyl acrylate unit except the said methyl methacrylate is about 4-30 weight part with respect to 100 weight part of acrylic resins. When the content of the alkyl acrylate unit is in the above range, it is easy to control the residual solvent while satisfying the optical properties.

The acrylic resin of the present invention preferably has a molecular weight of 300,000 to 2,500,000 g / mol. In this case, when the molecular weight is less than 300,000g / mol, the production efficiency of the film is lowered, and when it exceeds 2,500,000g / mol, the molding process is not easy. Moreover, it is preferable that the glass transition temperature (Tg) of the acrylic resin of this invention is 110 degreeC or more. Even if the glass transition temperature is less than the above range, the handleability is poor, which is undesirable.

The alkyl acrylate may include one or two or more copolymerized monomers selected from the group consisting of methyl acrylate, butyl acrylate, and butyl methacrylate.

The present invention is characterized in that it comprises a compound represented by the acrylic resin and the formula (1).

[Formula 1]

In Formula 1, R ₁ is a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms,

R ₂ and R ₃ are each independently a hydrogen atom, a halogen atom, a hydroxy group, or a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, and the composition ratio of m and n is 100: 0 to 50:50 and the molecular weight is 130,000 g / mol to 200,000 g / mol.

In this case, R ₁ is a substituted or unsubstituted phenyl group, R ₂ is a methyl group, and R ₃ is a substituted or unsubstituted methyl group, or a substituted or unsubstituted butyl group, but is not limited thereto.

Specifically, examples of the compound represented by Formula 1 include the following Formulas 2 to 4, but are not limited thereto. The compound represented by the formula (1) is preferably composed of 1 to 20 parts by weight, and more preferably 1 to 10 parts by weight based on 100 parts by weight of the acrylic resin. When the unit content of the compound represented by Formula 1 is within the above range, it is possible to control the phase difference of the film, high temperature process is possible by improving the heat resistance of the film, it is also effective to remove the residual solvent.

If the unit content of the compound represented by the formula (1) is less than 1 part by weight, the phase difference control effect is insufficient and the residual solvent remains due to impossibility of the high temperature process, the supportability of the film is insufficient, the film may be stretched due to peeling tension, 20 weight If it is excessive, the compatibility with the acrylic resin is lowered, the optical properties are lowered.

[Formula 2]

[Formula 3]

[Formula 4]

In Chemical Formulas 2 to 4,

R is a hydrogen atom, a halogen atom, a hydroxy group, a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms, and the composition ratio of m and n is 70: 30 And a molecular weight is from 130,000 g / mol to 200,000 g / mol.

The additive in this invention adds the nanoparticle which melt | dissolves and a deformation | transformation does not produce in the solvent of the said main dope liquid, and the impact strength of a film improves and film forming and film conveyance become easy. As the nanoparticles of the present invention, it is preferable to use one or two kinds of nanoparticles selected from the group consisting of silica or core-shell rubber particles (CSR). It is preferable that the diameter of the said nanoparticle is 100-300 nm. If the diameter of the nanoparticles is less than 100 nm, the effect of the desired invention does not appear sufficiently, and if the diameter of the nano particles exceeds 300 nm, the quality of the protective film becomes poor.

The content of the silica particles is preferably 0.01 part by weight to 0.1 parts by weight with respect to 100 parts by weight of the main liquid, and the content of the CSR particles is preferably 2 parts by weight to 10 parts by weight with respect to 100 parts by weight of the main liquid. When the content of the nanoparticles of the present invention is in the above range, it is possible to provide an acrylic film (protective film) excellent in both hardness and flexibility.

Supplementary additives may be further used in the production of the acrylic film. To the main dope liquid, various auxiliary additives according to the use in each manufacturing process, for example, an ultraviolet additive, fine particles, an infrared absorber, a release agent such as a release agent may be added. Specific kinds of such additives may be used without limitation as long as it is conventionally used in the art, the content is preferably used in a range that does not lower the physical properties of the film.

In the present invention, by adding the additive represented by the formula (1), not only the phase difference of the acrylic film can be adjusted, but also the high temperature process can be performed by improving the heat resistance property, thereby reducing the quality of the film due to the residual solvent by easy removal of the residual solvent. You can prevent it. Degradation of the film quality due to residual solvent Problems that may occur when the main dope solution in which the acrylic resin is dissolved in the solvent is applied to the metal support in the solvent casting process to form a semi-dry film and then peeled from the metal support This can have a significant impact on the quality of the acrylic film and its control is essential. For example, when the amount of the residual solvent is too small, it is difficult to peel the film from the support, and when the amount of the residual solvent is too large, the film becomes too soft and the self-supportability is insufficient, and the film is stretched due to the peeling tension. Can be. In addition, a large amount of organic solvent remaining in the film may be a problem in terms of product hazards.

It is preferable that the acrylic film (protective film) of this invention is 10-60 micrometers in film thickness. If the thickness of the protective film is less than 10㎛ does not exhibit sufficient retardation characteristics, if the thickness of the protective film exceeds 60㎛ is not suitable for use in thin polarizing plates.

The acrylic film of the present invention preferably has an in-plane retardation Ro of from 0 to 5 nm and a thickness direction retardation Rth of from -10 to -3 nm under the conditions of 23 ° C and 55% RH.

Hereinafter, the preferable manufacturing method of this invention is demonstrated in detail.

Preparation of Acrylic Resin

In order to manufacture the acrylic film of this invention, the copolymer resin (acrylic resin) of a methyl methacrylate and an alkyl acrylate monomer is manufactured first. There is no particular limitation on the copolymer production method of these monomers, and it can be prepared according to a copolymer resin production method well known in the art such as suspension polymerization, emulsion polymerization, bulk polymerization or solution polymerization.

It is preferable that the content of the alkyl acrylate unit except the methyl methacrylate is about 4 to 30 parts by weight based on 100 parts by weight of the acrylic resin.

The alkyl (meth) acrylate may include one or two or more copolymerized monomers selected from the group consisting of methyl acrylate, butyl acrylate, and butyl methacrylate. .

In this invention, it is preferable to use the acrylic resin which superposed | polymerized methyl methacrylate and butyl methacrylate.

Preparation of main dope liquid containing acrylic resin and compound represented by general formula (1)

In the present invention, an acrylic resin, a compound represented by Chemical Formula 1, an additive, and a solvent are sufficiently mixed with an inline mixer to prepare a main dope liquid.

In this invention, a film is manufactured by the solvent casting method (solution film formation method). The solvent casting method is a method of casting a main dope liquid obtained by dissolving an acrylic resin, a compound represented by the formula (1), and an additive in a casting solvent on a support, and evaporating the solvent to form a film. The preparation of the main dope liquid is based on a method of mixing the acrylic resin prepared above, the compound represented by Chemical Formula 1, and a coadditive with a casting solvent.

When the film is produced by the solvent casting method, the solvent for preparing the main dope liquid is preferably an organic solvent. As the organic solvent, halogenated hydrocarbons are preferably used, and halogenated hydrocarbons include chlorinated hydrocarbons, methylene chloride and chloroform, and methylene chloride is most preferably used.

Moreover, you may mix and use organic solvents other than halogenated hydrocarbon as needed. Organic solvents other than halogenated hydrocarbons include esters, ketones, ethers, alcohols and hydrocarbons. As ester, methyl formate, ethyl formate, propyl formate, pentyl formate, methyl acylate, ethyl acylate, pentyl acylate, etc. can be used, and as ketone, acetone, methyl ethyl ketone, diethyl ketone, di Isobutyl ketone, cyclopentanone, cyclohexanone, methylcyclohexanone, etc. can be used, and ether is diisopropyl ether, dimethoxymethane, dimethoxyethane, 1, 4- dioxane, 1, 3- dioxane Solan, tetrahydrofuran, anisole, phentol, etc. can be used, and alcohol, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, t-butanol, 1-pentanol, 2 -Pentanol, 2-methyl-2-butanol, cyclohexanol, 2-fluoroethanol, 2,2,2, -trifluoroethanol, 2,2,3,3-tetrafluoro-1-propanol Use

More preferably, methylene chloride may be used as the main solvent and alcohol may be used as the subsolvent. Specifically, the mixed solvent of methylene chloride and alcohol is preferably mixed in a weight ratio within the range of 80:20 to 95: 5.

To the main dope liquid, various auxiliary additives according to the use in each manufacturing process, for example, an ultraviolet additive, fine particles, an infrared absorber, a release agent such as a release agent may be added. The time to add an additive is determined according to the kind of additive, and the process of adding an additive at the end of main dope liquid preparation can also be performed.

In the present invention, a core-shell rubber particle (CSR) was used as an additive, and the diameter of the CSR particle is preferably 100 to 300 nm.

In the present invention, silica (silica) nanoparticles were used as another additive, the diameter of the nanoparticles is 100 to 300nm, the content is preferably 0.01 to 0.1 parts by weight based on 100 parts by weight of the main dope liquid.

The main dope liquid obtained as mentioned above can be manufactured by normal temperature, high temperature, or low temperature dissolution method.

Production Process

In the solvent casting method of the present invention, the main dope liquid is cast on the metal support from the nozzle of the press die and left for a predetermined time to form a film in a semi-dry state. Then, the said semi-dry state film is peeled from a metal support body, it transfers to a drying system, and it removes the said solvent by drying. And a uniaxial stretching process or a biaxial stretching process is performed with respect to the dry film. By carrying out this stretching process, it is possible to adjust the film uniformity and retardation value of a protective film.

Specifically, the main dope liquid obtained as described above is cast on the support through a casting die to form an acrylic sheet. Here, the support serves to vaporize the solvent present in the main dope liquid while transferring the main dope liquid extruded from the die to form a film into an acrylic film. It is preferable that the support or the surface thereof is made of a metal, and the surface is mirror-finished, and a metal belt such as a stainless steel belt is preferably used as the support. The surface temperature of the metal support is advantageous because the higher the temperature, the faster the evaporation of the solvent present in the main dope liquid. However, if the temperature is too high, the problem arises that the main dope liquid foams or the planarity deteriorates. It may vary depending on, but is preferably 0 to 75 ℃, more preferably 5 to 45 ℃. The support may be a metal support in the form of a planar conveyor belt.

The acrylic sheet thus formed is subjected to a drawing step in the tender, and the glass transition temperature (Tg) of the acrylic flake in the preheating process is 110 ° C. or more. After the acrylic film of the present invention is subjected to the stretching step in the tender under the above conditions, the film may be completed through the drying step in the dryer after removing the left and right ends of the film damaged by the clip or pin of the tender.

When using a tender stretching apparatus, it is preferable to use the apparatus which can control the grip length of a film from left to right by the right and left holding means of a tender. The stretching operation may be performed by dividing into multiple stages, and it is also preferable to perform biaxial stretching in the casting direction and the width direction. In addition, when performing biaxial stretching, simultaneous biaxial stretching may be performed and you may carry out in steps. In this case, with stage, it is also possible to perform extending | stretching different from a extending direction sequentially, it is also possible to divide extending | stretching of the same direction into multiple steps, and to add extending | stretching of another direction to any one of them. In addition, simultaneous biaxial stretching also includes the case where the stretching is performed in one direction and the other is relaxed by shrinking the tension. The preferable draw ratio of simultaneous biaxial stretching can be taken in the range of 1.01 time-2.0 time in both the width direction and the longitudinal direction.

The drying means generally blows hot air on both sides of the web, but there is also a means of heating the micro web instead of the wind. Too rapid drying tends to impair the planarity of the finished film.

Acrylic film of the present invention prepared according to the above method is characterized in that the water vapor transmission rate measured under the conditions of 60 ℃, 90% RH is 150g / m ^{2 ·} 24h or less.

Polarizer

The polarizing plate according to the present invention may include a polarizer and a protective film disposed on one side or both sides of the polarizer. Specifically, the polarizing plate of the present invention is a first protective film which is an acrylic film of the present invention; A polarizer formed on the first protective film; And it may include a second protective film formed on the polarizer.

In this case, the first protective film may be the acrylic film described above.

The polarizer disposed on the first protective film may include polyvinyl alcohol. The polyvinyl alcohol is preferably iodine dyed, but is not limited thereto. In addition, it is preferable that the film thickness of the polarizer is 3 to 30㎛, when the film thickness is in the above range, without having a great influence on the thickness of the polarizing plate which is the final product, it can efficiently perform the role as a polarizing layer.

In addition, the polarizing plate of the present invention may include a second protective film.

The second protective film may be formed on a polarizer and prepared as a main dope solution including an acrylic resin including an alkyl acrylate unit except for methyl methacrylate unit and methyl methacrylate. In addition, the second protective film may be the same as the first protective film of the present invention, but is not limited thereto. At this time, the film thickness of the second protective film is preferably 20 to 100㎛, but is not limited thereto. After arranging the polarizer formed on the first protective film described above and the second protective film to abut, the polarizing plate is completed. An adhesive layer may be further included between the polarizer and the second protective film to help adhesion of the two.

panel

The panel according to the present invention comprises a liquid crystal cell; A first polarizer disposed on one side of the liquid crystal cell; And a second polarizing plate disposed on the other side of the liquid crystal cell. At this time, the first polarizing plate and the second polarizing plate is preferably the above-mentioned polarizing plate.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the present invention is not limited by the following examples.

Manufacture of acrylic film

Example 1-1

<Step 1> acrylic resin

An acrylic resin having a content of 11 parts by weight of butyl methacrylate unit and a Tg 116 ° C. having a molecular weight of 950,000 g / mol shown in the following formula (5) was used.

[Formula 5]

(a and b are each an integer of 1 or more)

<Step 2> Preparation of Main Doping Liquid

17.11 parts by weight of the acrylic resin, 3.26 parts by weight of CSR particles, 0.03 parts by weight of silica particles, 64.12 parts by weight of methylene chloride, 14.08 parts by weight of methanol and 1.40 parts by weight of a compound represented by the following Chemical Formula 2, were sufficiently mixed in an in-line mixer to form a main dope. A liquid was prepared.

[Formula 2]

In Chemical Formula 2,

The composition ratio of m and n is 70:30, and molecular weight is 150,000 g / mol.

<Step 3> Production Process

Then, the main dope liquid was uniformly cast on a stainless band support having a width of 2000 mm using a belt casting apparatus. The solvent was evaporated off the stainless band support and peeled off from the stainless band support. Next, both ends of the web were gripped with a tender and stretched so that the draw ratio in the TD direction was 1.5 times. After extending | stretching, it hold | maintains for several seconds in the state which kept the width, relaxed the tension in the width direction, relaxed in the width direction, conveyed for 35 minutes in the drying section set to 90 degreeC, and performed drying, width 1900mm, and an edge part An acrylic film having a thickness of 40 µm having a width of 10 mm and a knurling having a height of 8 µm was prepared.

Example 1-2

The preparation of the main dope liquid was carried out in the same manner as in Example 1-1, except that 2.40 parts by weight of the compound represented by Formula 2 and 16.11 parts by weight of the acrylic resin represented by Formula 5 were added.

Example 1-3

The preparation of the main dope liquid was carried out in the same manner as in Example 1-1, except that 4.00 parts by weight of the compound represented by Formula 2 and 14.51 parts by weight of the acrylic resin represented by Formula 5 were added.

Examples 2-1 to 2-3

The preparation of the main dope liquid was carried out in the same manner as in Examples 1-1 to 1-3, except that the compound represented by the following Chemical Formula 3 was added.

[Formula 3]

In Chemical Formula 3,

R is a methyl group, the composition ratio of m and n is 70:30, and molecular weight is 150,000 g / mol.

Examples 3-1 to 3-3

In preparing the main dope liquid, the same process as in Examples 1-1 to 1-3 was performed except that the compound represented by the following Chemical Formula 4 was added.

[Formula 4]

In Chemical Formula 4,

R is a methyl group, the composition ratio of m and n is 70:30, and molecular weight is 150,000 g / mol.

Comparative Example 1

In preparing the main dope solution, the same method as in Example 1-1 was performed except that 18.51 parts by weight of the acrylic resin represented by Formula 5 was added without adding the compound represented by Formula 2 of Example 1-1. Was carried out.

Comparative Example 2

When preparing the main dope solution, it was carried out in the same manner as in Example 1-1 except for adding the compound represented by the formula (6) in the same amount instead of the compound represented by the formula (2).

[Formula 6]

Property evaluation

1. Measurement of phase difference value

For each of the acrylic films prepared in Examples 1-1 to 3-3, Comparative Examples 1 and 2, using an AxoScan (OPMF-1, Axometrics) optical measuring equipment under the environment of 23 ℃, 55% RH The retardation values Ro and Rth were measured at a wavelength of 590 nm, and the results are shown in Table 1.

2. Residual solvent measurement

For each of the acrylic films prepared in Examples 1-1 to 3-3, Comparative Examples 1 and 2, the content of the solvent remaining in the film after heating the film was analyzed by gas chromatography, and the results are shown. 1 is shown.

3. Moisture permeability measurement

For each of the acrylic films prepared in Examples 1-1 to 3-3, Comparative Examples 1 and 2, the moisture permeability was measured under an environment of 60 ° C. and 90% RH, and the results are shown in Table 1.

The moisture permeability is measured by placing calcium chloride (CaCl ₂ ) in the moisture permeation cup and the film prepared according to Examples 1-1 to 3-3, Comparative Examples 1 and 2 on the top of the moisture permeation cup to fix the sample with paraffin, and then the thermo-hygrostat (60 The difference between the weight before and the 24 hours after the input was quantified by dividing the permeable area.

Item	unit	Example 1-1	Example 1-2	Example 1-3	Example 2-1	Example 2-2	Example 2-3	Example 3-1	Example 3-2	Example 3-3	Comparative Example 1	Comparative Example 2
Allowable drawing temperature	℃	165 and below	185 or less	195 and below	165 and below	185 or less	195 and below	165 and below	185 or less	195 and below	145 or less	125 or less
Ro	Nm	2.5	2.1	2.9	2.4	2.1	2.8	2.5	2.1	2.5	3.2	2.5
Rth	Nm	-4.9	-7.1	-8.4	-5.0	-7.2	-8.2	-5.0	-7.2	-8.0	-2.1	-2.1
Tg	℃	117	118	120	117	118	120	117	118	120	116	100
Residual solvent	ppm	4,200	1,160	890	4,200	1,160	900	4,200	1,160	880	7,080	2,830
Breathability	g / m 2 / 24h	90	90	90	90	90	90	90	90	90	90	90

As shown in Table 1, the acrylic film prepared by the solvent casting method according to the present invention can provide a low-moisture-permeable acrylic film having a phase difference controlled by containing a compound of Formula 2, by improving the heat resistance of the film, a high temperature process It can be confirmed that it is also effective in removing residual solvent.

Preparation of Polarizer

Example 4-1

<Step 1> acrylic resin

An acrylic resin having a content of 11 parts by weight of butyl methacrylate unit and a Tg 116 ° C. having a molecular weight of 950,000 g / mol shown in the following formula (5) was used.

[Formula 5]

(a and b are each an integer of 1 or more)

<Step 2> Preparation of Main Doping Liquid

17.11 parts by weight of the acrylic resin, 3.26 parts by weight of CSR particles, 0.03 parts by weight of silica particles, 64.12 parts by weight of methylene chloride, 14.08 parts by weight of methanol and 1.40 parts by weight of a compound represented by the following Chemical Formula 2, were sufficiently mixed in an in-line mixer to form a main dope. A liquid was prepared.

[Formula 2]

In Chemical Formula 2,

The composition ratio of m and n is 70:30, and molecular weight is 150,000 g / mol.

<Step 3> Preparation of the first protective film: film forming process

Then, the main dope liquid was uniformly cast on a stainless band support having a width of 2000 mm using a belt casting apparatus. The solvent was evaporated off the stainless band support and peeled off from the stainless band support. Subsequently, both ends of the web were gripped with a tender and stretched so that the stretching ratio in the TD direction was 1.5 times in a 130 ° C temperature environment. After extending | stretching, it hold | maintains for several seconds in the state which kept the width, relaxed the tension in the width direction, relaxed in the width direction, conveyed for 35 minutes in the drying section set to 90 degreeC, and performed drying, width 1900mm, and an edge part The first protective film which was an acrylic film with a film thickness of 40 micrometers with knurling of width 10mm and height 8micrometer was prepared.

Step 4 Polarizer Preparation

The polyvinyl alcohol film of thickness 120micrometer was uniaxially stretched (temperature 110 degreeC, draw ratio 5 times). This was immersed in an aqueous solution containing 0.075 g of iodine, 5 g of potassium iodide and 100 g of water for 60 seconds, followed by immersion in an aqueous solution at 68 ° C. containing 6 g of potassium iodide, 7.5 g of boric acid, and 100 g of water. This was washed with water and dried to obtain a polarizer using a PVA film.

<Step 5> Preparation of the second protective film

Main dope prepared by sufficiently mixing with an in-line mixer, including 18.51 parts by weight of the acrylic resin, 3.26 parts by weight of CSR particles, 0.03 parts by weight of silica particles, 64.12 parts by weight of methylene chloride, and 14.08 parts by weight of methanol, except for the compound represented by Formula 2 below. Except for using the liquid, an acrylic film as a second protective film was prepared through the same process as in Step 3.

<Step 6> polarizing plate manufacturing

The prepared acrylic film and PVA were bonded to each other to prepare a polarizing plate.

The polarizer was immersed in a polyvinyl alcohol adhesive bath having a solid content of 2% by mass for 1 to 3 seconds, the excess adhesive adhered to the polarizer was lightly wiped off, and the polarizer was placed on one side of the first protective film. In addition, the second protective film is disposed on the other side of the polarizer in which the first protective film is not disposed. The laminated first protective film, polarizer and second protective film were bonded at a pressure of 20 to 30 N / cm ² and a conveyance speed of about 2 m / min. In the 80 degreeC dryer, the sample which bonded the said polarizer, the 1st protective film, and the 2nd protective film was dried for 2 minutes, and the polarizing plate was produced.

Example 4-2

The preparation of the main dope liquid was carried out in the same manner as in Example 4-1, except that 2.40 parts by weight of the compound represented by Formula 2 was added and 16.11 parts by weight of the acrylic resin represented by Formula 5.

Example 4-3

The preparation of the main dope liquid was carried out in the same manner as in Example 4-1, except that 4.00 parts by weight of the compound represented by Formula 2 was added and 14.51 parts by weight of the acrylic resin represented by Formula 5.

Examples 5-1 to 5-3

When preparing the main dope solution of the first protective film, it was carried out in the same manner as in Examples 4-1 to 4-3 except that the compound represented by the following formula (3) was added.

[Formula 3]

In Chemical Formula 3,

R is a methyl group, the composition ratio of m and n is 70:30, and molecular weight is 150,000 g / mol.

Examples 6-1 to 6-3

When preparing the main dope solution of the first protective film, it was carried out in the same manner as in Examples 4-1 to 4-3 except that the compound represented by the following formula (4) was added.

[Formula 4]

In Chemical Formula 4,

R is a methyl group, the composition ratio of m and n is 70:30, and molecular weight is 150,000 g / mol.

Comparative Example 3

When preparing the main dope solution of the first protective film, it was carried out in the same manner as in Example 4-1 except that the compound represented by the formula (2) of Example 4-1 was not added.

Comparative Example 4

A triacetate cellulose (TAC) series retardation film was used as the first protective film and the second protective film to prepare a polarizing plate.

Property evaluation

1. Measurement of phase difference value

For each of the first protective films prepared in Examples 4-1 to 6-3, Comparative Examples 3 and 4, using the AxoScan (OPMF-1, Axometrics) optical measuring equipment of 23 ℃, 55% RH The retardation values Ro and Rth were measured at a wavelength of 590 nm under environment, and the results are shown in Table 2.

2. Moisture permeability measurement

For each of the first protective film prepared in Examples 4-1 to 6-3, Comparative Examples 3 and 4, the moisture permeability was measured in an environment of 60 ℃, 90% RH and the results are shown in Table 2.

The moisture permeability is measured by putting calcium chloride (CaCl ₂ ) in the moisture permeation cup and the film prepared according to Examples 4-1 to 6-3, Comparative Examples 3 and 4 on the top of the moisture permeation cup to fix the sample with paraffin, and then the thermo-hygrostat (60 The difference between the weight before and the 24 hours after the input was quantified by dividing the permeable area.

Item		unit	Example 4-1	Example 4-2	Example 4-3	Example 5-1	Example 5-2	Example 5-3	Example 6-1	Example 6-2	Example 6-3	Comparative Example 3	Comparative Example 4
Phase difference	Ro	nm	2.5	2.1	2.9	2.4	2.1	2.8	2.5	2.1	2.5	3.2	5.4
	Rth	nm	-4.9	-7.1	-8.4	-5.0	-7.2	-8.2	-5.0	-7.2	-8.0	-2.1	0.5
Breathability	150g / m 2 · 24h	℃	90	90	90	90	90	90	90	90	90	90	700

As shown in Table 2, the polarizing plate prepared by applying the acrylic film prepared by the solvent casting method according to the present invention may provide a low moisture-permeable polarizing plate containing a compound of the formula (2) is phase difference controlled.

Manufacture of panels

Example 7-1

<Step 1> acrylic resin

An acrylic resin having a content of 11 parts by weight of butyl acrylate unit and a Tg 116 ° C. having a molecular weight of 950,000 g / mol shown in the following formula (5) was used.

[Formula 5]

(a and b are each an integer of 1 or more)

<Step 2> Preparation of Main Doping Liquid

17.11 parts by weight of the acrylic resin, 3.26 parts by weight of CSR particles, 0.03 part by weight of silica particles, 64.12 parts by weight of methylene chloride, 14.08 parts by weight of methanol and 1.40 parts by weight of a compound represented by the following Formula 2, are sufficiently mixed in an in-line mixer to form a main dope. A liquid was prepared.

[Formula 2]

In Chemical Formula 2,

The composition ratio of m and n is 70:30, and molecular weight is 150,000 g / mol.

<Step 3> Preparation of the first protective film: film forming process

Then, the main dope liquid was uniformly cast on a stainless band support having a width of 2000 mm using a belt casting apparatus. The solvent was evaporated off the stainless band support and peeled off from the stainless band support. Subsequently, both ends of the web were gripped with a tender and stretched so that the stretching ratio in the TD direction was 1.5 times in a 130 ° C temperature environment. After extending | stretching, it hold | maintains for several seconds in the state which kept the width, relaxed the tension in the width direction, relaxed in the width direction, conveyed for 35 minutes in the drying section set to 90 degreeC, and performed drying, width 1900mm, and an edge part The first protective film which was an acrylic film with a film thickness of 40 micrometers with knurling of width 10mm and height 8micrometer was prepared.

Step 4 Polarizer Preparation

The polyvinyl alcohol film of 120 micrometers in thickness was uniaxially stretched (temperature 110 degreeC, draw ratio 5 times). This was immersed in an aqueous solution containing 0.075 g of iodine, 5 g of potassium iodide and 100 g of water for 60 seconds, followed by immersion in an aqueous solution at 68 ° C. containing 6 g of potassium iodide, 7.5 g of boric acid, and 100 g of water. This was washed with water and dried to obtain a polarizer using a PVA film.

<Step 5> Preparation of the second protective film

Main dope liquid prepared by sufficiently mixing with an in-line mixer including 18.51 parts by weight of the acrylic resin, 3.26 parts by weight of CSR particles, 0.03 parts by weight of silica particles, 64.12 parts by weight of methylene chloride, and 14.08 parts by weight of methanol, except for the compound represented by Formula 2. Except for using, to prepare an acrylic film of the second protective film through the same process as in step 3.

<Step 6> polarizing plate manufacturing

The prepared acrylic film and PVA were bonded to each other to prepare a polarizing plate.

The polarizer was immersed in a polyvinyl alcohol adhesive bath having a solid content of 2% by mass for 1 to 3 seconds, the excess adhesive adhered to the polarizer was lightly wiped off, and the polarizer was placed on one side of the first protective film. In addition, the second protective film is disposed on the other side of the polarizer in which the first protective film is not disposed. The laminated first protective film, polarizer and second protective film were bonded at a pressure of 20 to 30 N / cm ² and a conveyance speed of about 2 m / min. The sample which bonded the said polarizer, the 1st protective film, and the 2nd protective film in 80 degreeC dryer was dried for 2 minutes, and the polarizing plate was produced.

Step 7 Manufacture of Panel

After the pressure-sensitive adhesive was coated on the polarizing plate second protective film with respect to the prepared polarizing plate, the polarizing plate was attached to each of the polarizing plate toward the liquid crystal cell to prepare a panel.

Example 7-2

The preparation of the main dope liquid was carried out in the same manner as in Example 7-1, except that 2.40 parts by weight of the compound represented by Formula 2 and 16.11 parts by weight of the acrylic resin represented by Formula 5 were added.

Example 7-3

The preparation of the main dope liquid was carried out in the same manner as in Example 7-1, except that 4.00 parts by weight of the compound represented by Formula 2 and 14.51 parts by weight of the acrylic resin represented by Formula 5 were added.

Examples 8-1 to 8-3

In preparing the main dope solution of the first protective film, it was carried out in the same manner as in Examples 7-1 to 7-3 except that the compound represented by the following formula (3) was added.

[Formula 3]

In Chemical Formula 3,

R is a methyl group, the composition ratio of m and n is 70:30, and molecular weight is 150,000 g / mol.

Examples 9-1 to 9-3

When preparing the main dope solution of the first protective film, it was carried out in the same manner as in Examples 7-1 to 7-3 except for adding the compound represented by the following formula (4).

[Formula 4]

In Chemical Formula 4,

R is a methyl group, the composition ratio of m and n is 70:30, and molecular weight is 150,000 g / mol.

Comparative Example 5

A panel to which a conventional polarizer having high retardation value was applied was manufactured.

Comparative Example 6

A panel to which a polarizing plate using a triacetate cellulose (TAC) series retardation film as a first protective film and a second protective film was applied was prepared.

Property evaluation

1. Measurement of phase difference value

For each of the first protective films prepared in Examples 7-1 to 9-3, Comparative Examples 5 and 6, using the AxoScan (OPMF-1, Axometrics) optical measuring equipment of 23 ℃, 55% RH The retardation values Ro and Rth were measured at a wavelength of 590 nm under the environment, and the results are shown in Table 3.

2. Moisture permeability measurement

For each of the acrylic films prepared in Examples 7-1 to 9-3, Comparative Examples 5 and 6, the moisture permeability was measured under an environment of 60 ° C. and 90% RH, and the results are shown in Table 3.

The moisture permeability is measured by putting calcium chloride (CaCl ₂ ) in the moisture absorption cup and the film prepared according to Examples 7-1 to 9-3, Comparative Examples 5 and 6 on the upper surface of the moisture absorption cup to fix the sample with paraffin, a thermo-hygrostat (60 The difference between the weight before and the 24 hours after the input was quantified by dividing the permeable area.

[Correction under Rule 91 26.04.2019]

As shown in Table 3, the panel manufactured by using the polarizing plate to which the acrylic film prepared by the solvent casting method is applied according to the present invention may contain a compound of Formula 2 and may provide a panel resistant to diagonal vision and resistant to moisture. .

Claims (12)

1. Acrylic resins comprising alkyl acrylate units excluding methyl methacrylate units and methyl methacrylate; And

   A low moisture-permeable acrylic film prepared by the solvent casting method using the main dope solution containing 1 to 20 parts by weight of the compound represented by the following formula (1):

   [Formula 1]

   

   In Formula 1, R ₁ is a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms,

   R ₂ and R ₃ are each independently a hydrogen atom, a halogen atom, a hydroxy group, or a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, and the composition ratio of m and n is 100: 0 to 50:50 and the molecular weight is 130,000 g / mol to 200,000 g / mol.
2. The method of claim 1,

   The said acryl film is 0-5 nm in-plane retardation Ro measured on 23 degreeC and 55% RH conditions, and the thickness direction retardation Rth is -10-3 nm, The low moisture-permeable acrylic film characterized by the above-mentioned.
3. The method of claim 1,

   The acrylic film has a film thickness of 10 to 60 µm, and the moisture permeability of the film measured under the conditions of 60 ° C. and 90% RH is 150 g / m ^{2 ·} 24 h or less.
4. The method of claim 1,

   The compound is a low moisture-permeable acrylic film represented by any one of the following formula (2):

   [Formula 2]

   

   [Formula 3]

   

   [Formula 4]

   

   In Chemical Formulas 2 to 4,

   R is a hydrogen atom, a halogen atom, a hydroxyl group, a substituted or unsubstituted C1-C12 alkyl group, or a substituted or unsubstituted C6-C50 aryl group, and the composition ratio of m and n is 70:30 And a molecular weight is from 130,000 g / mol to 200,000 g / mol.
5. It includes a polarizer and a protective film disposed on one side or both sides of the polarizer,

   The protective film is a solvent casting method using an acrylic resin containing a methyl methacrylate unit and an alkyl acrylate unit excluding methyl methacrylate and a main dope solution containing 1 to 20 parts by weight of a compound represented by Formula 1 below. The low moisture-permeable polarizing plate formed into a film.

   [Formula 1]

   

   In Formula 1, R ₁ is a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms,

   R ₂ and R ₃ are each independently a hydrogen atom, a halogen atom, a hydroxy group, or a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms,

   The composition ratio of m and n is 100: 0-50: 50, and molecular weight is 130,000g / mol-200,000g / mol.
6. The method of claim 5,

   The protective film has a low moisture-permeable polarizing plate having an in-plane retardation Ro of 0 to 5 nm and a thickness direction retardation Rth of -10 to -3 nm measured under the conditions of 23 ° C. and 55% RH.
7. The method of claim 5,

   The protective film has a film thickness of 10 to 60㎛, moisture permeability of the film measured under the conditions of 60 ℃, 90% RH is 150g / m ² · 24h or less low moisture-permeable polarizing plate.
8. The method of claim 5,

   The compound is a low moisture-permeable polarizing plate represented by any one of the following formulas (2) to (4).

   [Formula 2]

   

   [Formula 3]

   

   [Formula 4]

   

   In Chemical Formulas 2 to 4,

   R is a hydrogen atom, a halogen atom, a hydroxyl group, a substituted or unsubstituted C1-C12 alkyl group, or a substituted or unsubstituted C6-C50 aryl group, and the composition ratio of m and n is 70:30 And a molecular weight is from 130,000 g / mol to 200,000 g / mol.
9. Liquid crystal cell; And

   It includes a polarizing plate disposed on one side or both sides of the liquid crystal cell,

   The polarizing plate is a polarizer; And a protective film disposed on one side or both sides of the polarizer,

   The protective film is an acrylic resin comprising a methyl methacrylate unit and alkyl acrylate units other than methyl methacrylate; And a panel formed by a solvent casting method using a main dope solution containing 1 to 20 parts by weight of a compound represented by Formula 1 below:

   [Formula 1]

   

   In Chemical Formula 1, R ₁ is a substituted or unsubstituted aryl group having 6 to 50 ring carbon atoms,

   R ₂ and R ₃ are each independently a hydrogen atom, a halogen atom, a hydroxy group, or a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms,

   The composition ratio of m and n is 100: 0-50: 50, and molecular weight is 130,000g / mol-200,000g / mol.
10. The method of claim 9,

    The protective film is a panel in which the in-plane retardation Ro measured under the conditions of 23 ℃, 55% RH is 0 to 5nm, the thickness direction retardation Rth is -10 to -3nm.
11. The method of claim 9,

    The protective film has a film thickness of 10 to 60㎛, moisture permeability of the film measured under the conditions of 60 ℃, 90% RH is 150g / m ^{2 ·} 24h or less panel.
12. The method of claim 9,

    The compound is a panel represented by any one of the following formulas (2) to (4):

    [Formula 2]

    

    [Formula 3]

    

    [Formula 4]

    

    In Chemical Formulas 2 to 4,

    R is a hydrogen atom, a halogen atom, a hydroxyl group, a substituted or unsubstituted C1-C12 alkyl group, or a substituted or unsubstituted C6-C50 aryl group, and the composition ratio of m and n is 70:30 And a molecular weight is from 130,000 g / mol to 200,000 g / mol.