KR101662876B1 - Protection film for polarizer film having low moisture permeability and polarizer plate and liquid crystal displaty including the same - Google Patents

Abstract

The present invention provides a C _{1 ~ 16} alkyl group or a polarizer protective film comprising a polyamide resin containing at least one alicyclic structure in the main chain, moisture permeability is very low, and high in transmittance and is excellent in toughness. As a result, it is possible to provide a polarizing plate and a liquid crystal display device having excellent optical characteristics and excellent durability such as moisture resistance and toughness.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polarizer protective film having a low moisture permeability and a polarizing plate and a liquid crystal display device having the polarizer protective film. 2. Description of the Related Art [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polarizer protective film and a polarizer plate including the polarizer protective film, and more specifically to a polarizer protective film comprising a polyamide resin containing an aliphatic hydrocarbon chain or an aliphatic hydrocarbon ring in the main chain and a polarizer comprising the polarizer protective film.

Recently, a display technology using various methods such as a plasma display panel (PDP), a liquid crystal display (LCD) and the like replacing a conventional cathode ray tube has been proposed and marketed with the development of optical technology. Such indoor display displays are becoming increasingly larger and thinner, and outdoor outdoor displays are becoming smaller and lighter. In order to further improve the function of such a display, various optical films have been used since early.

Although the material used for the optical film may vary depending on the type of display, it generally has properties such as high transmittance, optical isotropy, defect free surface, high heat resistance and moisture resistance, high flexibility, high toughness, low shrinkage, Should be equipped.

The polarizer generally adheres a protective film to one side or both sides of the polarizer in order to enhance and protect the durability and mechanical properties of the polarizer made of polyvinyl alcohol. As the polarizer protective film, a cellulose-based film, a polyester-based film, a polyacrylate-based film, a polycarbonate-based film, and a cyclic olefin-based film can be applied.

In particular, a triacetyl cellulose film (hereinafter referred to as a "TAC film") having properties such as transmittance, optical isotropy and defect-free surface has been mostly used as a protective film. However, the triacetyl cellulose film is weak in heat and humidity. Therefore, when the cellulose acylate film is used in a high temperature and high humidity environment for a long time, problems such as a decrease in polarization degree and a light leakage phenomenon due to excessive leakage of light due to moisture deterioration occur.

As a result, when the polarizing plate made of the protective films is used in a high temperature or high humidity environment for a long time, the degree of polarization is lowered, the polarizer and the protective film are separated from each other, and the optical characteristics are lowered.

Specifically, the triacetylcellulose-based film has a high moisture permeability due to a large number of hydrophilic functional groups in the molecular chain structure, resulting in deformation of the protective film under heat and humidity conditions or dissociation of iodide ions in the polarizer, (R _in ) and the thickness direction retardation (R _th ) are significantly changed according to such an environmental change. In particular, the retardation change with respect to the incident light in the oblique direction is large. When a polarizing plate using a triacetylcellulose film having such characteristics as a protective film is applied to a liquid crystal display device, there is a problem that the viewing angle characteristics are changed according to the environmental change of the ambient temperature and humidity, and the image quality is deteriorated.

On the other hand, an acrylic resin such as polymethyl (meth) acrylate is also known as a material having excellent transparency and optical isotropy. However, acrylic resin is fragile due to external impact and has low heat resistance. Therefore, May be deteriorated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the present invention to provide a polarizer protective film having low moisture permeability, high transmittance and excellent toughness, and a polarizer and a polarizer including the same.

In one aspect, the present invention provides a C _{1 ~ 16} alkyl group or the following, comprising: at least one alicyclic structure in the plane direction retardation (R _in) value defined by Equation 1] -10nm to 10nm in the main chain, And a thickness direction retardation (R _th ) value defined by the following formula (2) is -10 nm to 10 nm.

&Quot; (1) " R _in = (n _x - n _y ) x d,

&_Quot; (2) " R _th = (n _z - n _y ) x d

In the above equations (1) and (2)

n _x is the largest refractive index among the refractive indices in the plane direction of the film,

n _y is a refractive index in a direction perpendicular to n _{x of the} refractive index in the plane direction of the film,

n _z is the refractive index in the thickness direction,

d is the thickness of the film.

At this time, the polarizer protective film preferably has a moisture permeability of 140 g / m ² day or less and a transmittance of 90% or more.

It is also preferable that the impact energy at which the polarizer protective film starts to be broken is 1000 kN · m / m ³ or more.

In another aspect, the present invention provides a polarizing plate and a liquid crystal display including the polarizer protective film.

The polarizer-protective film according to the present invention by including an aliphatic polyamide resin comprising a C _{1 ~ 16} alkyl group or at least one alicyclic structure in the main chain, the moisture permeability of the protection film is very low, and high in permeability, toughness is excellent Do.

As a result, it is possible to provide a polarizing plate and a liquid crystal display device having excellent optical characteristics and excellent durability such as moisture resistance and toughness.

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

The inventors of the present invention have conducted studies to improve the durability of a polarizing plate in a high temperature and high humidity environment due to high moisture permeability of a cellulose-based film widely used as a polarizer protective film, and as a result, It has been found that when a polarizer protective film comprising an aliphatic polyamide resin containing a hydrocarbon ring is used, the moisture permeability is very low, the transparency is high, and the toughness is excellent.

That is, the polarizer protective film has a main chain according to the invention C _{1 ~ 16} alkyl group or the following, comprising a polyamide resin containing at least one alicyclic structure phase plane direction defined by the formula 1] (R _in value of -10 nm to 10 nm and a thickness direction retardation (R _th ) defined by the following formula (2) is -10 nm to 10 nm.

&Quot; (1) " R _in = (n _x - n _y ) x d,

&_Quot; (2) " R _th = (n _z - n _y ) x d

Where n _x is the largest refractive index among the refractive indices in the plane direction of the film, n _y is the refractive index in the direction perpendicular to n _x of the film surface refractive index, and n _z Is the refractive index in the thickness direction, and d is the thickness of the film.

The present invention is characterized by the use of an aliphatic polyamide resin. The polyamide itself has excellent toughness, and is composed of an aliphatic chain and alicyclic group, which is a hydrophobic group, and thus has an excellent effect of lowering the moisture permeability. Particularly, when the aliphatic polyamide resin is used, the aromatic polyamide resin is excellent in chemical resistance and impact resistance as compared with the aromatic polyamide resin and has a large retardation manifestation, Can be supplemented.

On the other hand, it is more preferable that the polyamide resin of the present invention essentially contains at least one alicyclic structure. The alicyclic polyamide resin has better heat resistance than the polyamide resin having an aliphatic chain structure.

More particularly, the polyamide resin of the main chain including a C _{1 ~ 16} alkyl group or at least one alicyclic structure preferably includes a unit represented by Chemical Formula 1 or 2 below.

[Chemical Formula 1]

Wherein A is a C _{2 -16} aliphatic hydrocarbon chain or a C _{5 -14} aliphatic hydrocarbon ring, X ₁ is a halogen atom or a C _{1 -6} alkyl group, a is an integer of 0 to 3, n is 5 Lt; / RTI >

In the formula (1), the C _{2 -16} aliphatic hydrocarbon chain means a hydrocarbon moiety having 2 to 16, 4 to 14, or 6 to 12 carbon atoms, and includes, but is not limited to, methylene An ethylene group, a propylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, a heptamethylene group, a nonanemethylene group, a decamethylene group, an undecamethylene group, a dodecamethylene group, , Tetradecamethylene group, pentadecamethylene group, hexadecamethylene group, and the like.

Further, in A of Formula 1, C _{5 -14} aliphatic hydrocarbon ring of 5 to 14, or 5 to 10, or 5 to 6 ring carbon cyclic saturated or unsaturated non-aromatic mono-, bicyclic But is not limited to, a cycloalkane ring such as a cyclopentane ring or a cyclohexane ring, a cycloalkene ring such as a cyclopentene ring, a cyclohexene ring or a cyclooctene ring, Rings, and the like.

On the other hand, in the above formula (1), the bonding position of the polyamide resin of A with the main chain is not particularly limited and may be an asymmetric position or a symmetric position. For example, when A is a cyclohexane ring, it may be a cyclohexane ring in which the 1,3 carbon is bonded to the main chain, or a cyclohexane ring in which the 1,4 carbon is bonded to the main chain.

Further, in X ₁ of Formula _1, C 1 _{- 6} alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a t- butyl group can be given. Examples. At this time, X ₁ is substituted with hydrogen at an arbitrary position of A.

(2)

In Formula 2, B and C are each independently a C _{2 -16} aliphatic hydrocarbon chain or a C _{5 -14} aliphatic hydrocarbon ring, X ₂ and X ₃ are each independently a halogen atom or a C _1-6 alkyl group, b And c are each independently an integer of 0 to 3, and m is an integer of 5 to 10,000.

In Formula 2, it is more preferable that at least one of B and C is a C _{5 -14} aliphatic hydrocarbon ring.

Herein, in B and C of the above formula (2), the C _{2 -16} aliphatic hydrocarbon chain means a hydrocarbon part of 2 to 16, or 4 to 14, or 6 to 12 carbon atoms, , Methylene group, ethylene group, propylene group, trimethylene group, tetramethylene group, pentamethylene group, hexamethylene group, heptamethylene group, nonanemethylene group, decamethylene group, undecamethylene group, dodecamethylene group, trideca A methylene group, a tetradecamethylene group, a pentadecamethylene group, a hexadecamethylene group, and the like.

Further, in the B and C in the formula 2, C _{5 -14} aliphatic hydrocarbon ring of 5 to 14, or 5 to 10, or 5 to 6 ring carbon cyclic saturated or unsaturated non-aromatic mono, Bicyclic and tricyclic hydrocarbon moieties, and includes, but is not limited to, cycloalkane rings such as cyclopentane rings and cyclohexane rings, cycloalkane rings such as cyclopentene rings, cyclohexene rings, and cyclooctene rings cycloalkene ring, and the like.

On the other hand, in the formula (2), the bonding position of the polyamide resin of B and C to the main chain is not particularly limited and may be an asymmetric position or a symmetric position. For example, when B or C is a cyclohexane ring, it may be a cyclohexane ring in which the 1,3 carbon is bonded to the main chain, or a cyclohexane ring in which the 1,4 carbon is bonded to the main chain.

In the above Formula 2, X ₂ and X ₃ of the C _{1 - 6} alkyl group as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a t- butyl group can be given. Examples . X ₂ is substituted and bonded to hydrogen at any position of B, and X ₃ is substituted and bonded to hydrogen at any position of C;

On the other hand, though not limited thereto, it is more preferable that the polyamide resin includes a unit represented by the following formula (3).

(3)

In the general formula 3, D is a C _{2 -16} aliphatic hydrocarbon chain, E and F are each independently a C _{5 -14} aliphatic hydrocarbon ring, X _4, X ₅ and X ₆ is independently a halogen atom or a C ₁ each _-6 alkyl group, X ₇ is a single bond, a methylene group or a dimethylmethylene group, d, e and f are each independently 0 to an integer of 2, k is an integer of 5 to 10,000.

In the formula (D), the C _{2 -16} aliphatic hydrocarbon chain refers to a hydrocarbon moiety of 2 to 16, or 4 to 14, or 6 to 12 carbon atoms, including, but not limited to, methylene An ethylene group, a propylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, a heptamethylene group, a nonanemethylene group, a decamethylene group, an undecamethylene group, a dodecamethylene group, , Tetradecamethylene group, pentadecamethylene group, hexadecamethylene group, and the like.

Further, in E and F of the above formula (3), E and F are more preferably a cyclohexane ring, and the bonding position of the polyamide resin of E and F to the main chain is not particularly limited But may be an asymmetric position or a symmetrical position. For example, when E and F are cyclohexane rings, the 1,3-carbon may be a cyclohexane ring bonded to the main chain, or a 1,4-cyclohexane ring bonded to the main chain.

In Formula 3, X ₄ and X ₅ And C ₁ of X _{6 - 6} in an alkyl group is a methyl group, may be mentioned an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a t- butyl group. Examples. Wherein X ₄ is substituted and bound to hydrogen at any position of D, X ₅ is substituted and substituted with hydrogen at any position of E, and X ₆ is substituted with hydrogen at any position of F .

The weight average molecular weight of the polyamide resin may be about 1,000 to about 300,000, and preferably about 10,000 to about 200,000. When the weight average molecular weight is in the range, mechanical properties such as toughness and workability are excellent.

In addition, the polyamide resin preferably has an amorphous or semi-crystal structure. When the crystallinity of the polyamide based resin is high, the transmittance is low and it may become difficult to use as an optical film.

On the other hand, the method for producing the polarizer protective film according to the present invention using the above polyamide resin is not particularly limited. For example, a solution casting method (solution casting method), a melt extrusion method, And any suitable film forming method such as a molding method. Among these film forming methods, a solution casting method (solution casting method) and a melt extrusion method are preferable.

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; Esters such as ethyl acetate and butyl acetate; Ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone; Alcohols such as methanol, ethanol, isopropanol, butanol, isobutanol, methyl cellosolve, ethyl cellosolve and butyl cellosolve; Ethers such as tetrahydrofuran and dioxane; Halogenated hydrocarbons such as dichloromethane, chloroform and carbon tetrachloride; Dimethylformamide; Dimethyl sulfoxide and the like. These solvents may be used alone or in combination of two or more.

Examples of the apparatus for carrying out the solution casting method (solution casting method) include a drum casting machine, a band 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 占 폚, more preferably 200 to 300 占 폚.

When a film is formed by the T-die method, a T-die is attached to the tip of a known single-screw extruder or a twin-screw extruder, and a rolled film is obtained by winding a film extruded in a film form. At this time, uniaxial stretching can also be performed by stretching in the extrusion direction by appropriately adjusting the temperature of the winding roll. Further, simultaneous biaxial stretching, sequential biaxial stretching, and the like can also be carried out by stretching the film in a direction perpendicular to the extrusion direction.

The polyamide-based film may be either an unoriented film or a stretched film, but in general, when the polyamide film is stretched, the retardation value becomes large and may not be suitable for use as a protective film. Therefore, Is more preferable.

The polyamide-based film may be subjected to heat treatment (annealing) or the like in order to stabilize its optical isotropy or mechanical properties. The heat treatment conditions are not particularly limited and any suitable conditions known in the art can be employed.

If necessary, the protective film according to the present invention may be subjected to surface treatment such as alkali treatment, corona treatment, plasma treatment or coating treatment on at least one side of the protective film in order to improve the adhesive strength or adhesion.

The polarizer protective film according to the present invention may be formed, for example, by forming a coating layer on at least one side of a transparent film, and the coating layer is formed by a method of forming using the coating composition according to the present invention .

On the other hand, since the polyamide resin generally has low crystallinity, excellent toughness and brittleness, the polarizer protective film of the present invention produced using the polyamide resin has low moisture permeability, high transmittance and high toughness And is suitable for use as a laminated film used for a polarizing plate.

On the other hand, the moisture permeability of the polarizer protective film prepared as described above and 140g / m ² day or less, preferably 120g / m ² day or smaller, more preferably be 100g / m ² day or less, or 50g / m ² day have. When the moisture permeability of the polarizer protective film satisfies the above range, deformation of the protective film does not occur under the humidity resistant condition, and the effect of dissociation of the iodide ion of the polarizer is suppressed to prevent the deterioration of the performance of the polarizer.

In addition, it is preferable that the polarizer protective film produced as described above has a transmittance of 90% or more.

Meanwhile, the polarizer protective film according to the present invention has an impact energy (IE) of 1000 kN · m / m ³ or more, preferably 2000 kN · m / m < ³ >, more preferably 3500 kNm / m < ³ >.

In the present invention, the drop impact test is one of the methods for evaluating the toughness of the protective film. When the drop is dropped on a film which is tightly fixed at a certain height, impact energy per unit volume . The impact energy is defined by the following equation (3), and the larger the impact energy is, the stronger the impact resistance and the toughness are.

 &Quot; (3) "

Impact Energy = Gravity Acceleration X Weight of Diameter X Height / (Film Thickness X Film Area)

On the other hand, the polarizer protective film has a retardation value (R _in ) of -10 nm to 10 nm and a thickness direction retardation (R _th ) defined by the following formula (2) (R _in ) of -5 nm to 5 nm, and a thickness direction retardation (R _th ) value of about -5 nm to 5 nm.

&Quot; (1) " R _in = (n _x - n _y ) x d,

&_Quot; (2) " R _th = (n _z - n _y ) x d

In the above equations (1) and (2)

n _x is the largest refractive index among the refractive indices in the plane direction of the film,

n _y is a refractive index in a direction perpendicular to n _{x of the} refractive index in the plane direction of the film,

n _z is the refractive index in the thickness direction,

d is the thickness of the film.

Further, the thickness of the polarizer protective film of the present invention may be in the range of 5 占 퐉 to 80 占 퐉, preferably 10 占 퐉 to 60 占 퐉. When the thickness of the polarizer protective film satisfies the above range, it is possible to reduce the thickness of the protective film, and the size and weight of the liquid crystal display device including the protective film can be reduced.

The final aspect of the present invention relates to a polarizing plate including the polarizer optical film of the present invention and a liquid crystal display including the polarizing plate. More specifically,

In this specification, the polarizing plate means a state including a polarizer and a protective film, and the polarizer may be a film made of polyvinyl alcohol (PVA) containing iodine or a dichroic dye. The polarizer may be prepared by saponifying iodine or a dichroic dye to a PVA film, but the production method thereof is not particularly limited.

On the other hand, in the polarizing plate of the present invention, the polarizer protective film and the polarizer can be adhered by a method known in the art. For example, by an adhesive method using an adhesive. That is, first, an adhesive is coated on the surface of a protective film or a PVA film as a polarizer (polarizing film) using a roll coater, a gravure coater, a bar coater, a knife coater or a capillary coater. Before the adhesive is completely dried, the protective film and the polarizer are adhered to each other by heat pressing or hot pressing at a temperature of room temperature. When a hot-melt type adhesive is used, a hot press roll is used.

Examples of the adhesive that can be used for bonding the protective film and the polarizer include a PVA adhesive, a polyurethane adhesive, an epoxy adhesive, a styrene-butadiene rubber (SBR) adhesive, a hot melt adhesive, a UV curable adhesive, and the like. When the above polyurethane-based adhesive is used, it is preferable to use a polyurethane-based adhesive prepared by using an aliphatic isocyanate-based compound which is not yellowed by light. In the case of using the UV curable adhesive, it is preferable to apply UV curable adhesive after application of the adhesive.

In addition, the polarizing plate of the present invention preferably has a pressure-sensitive adhesive layer for easy lamination to a liquid crystal cell or the like, and may be disposed on one side or both sides of the polarizing plate. It is preferable that the adhesive is sufficiently cured by heat or ultraviolet rays after bonding to improve the mechanical strength to the level of the adhesive, and the adhesive strength to the surface of the adhesive is high so that the adhesive can be peeled without any one of the two films .

The pressure-sensitive adhesive which can be used preferably exhibits excellent optical transparency and exhibits appropriate wettability, cohesiveness and adhesive property. Specific examples thereof include a pressure-sensitive adhesive prepared by appropriately preparing polymers such as acrylic polymers, silicone polymers, polyesters, polyurethanes, polyethers, and synthetic rubbers as base polymers.

The present invention also provides a liquid crystal display device including the polarizer, that is, a liquid crystal display device including the polarizer protective film according to the present invention.

For example, a liquid crystal display device according to the present invention includes a liquid crystal cell and first and second polarizing plates provided on both sides of the liquid crystal cell, wherein at least one of the first polarizing plate and the second polarizing plate And is a polarizing plate according to the present invention. That is, one or two or more polarizer protective films according to the present invention may be provided between the first polarizer and the liquid crystal cell, between the second polarizer and the liquid crystal cell, or between the first polarizer and the liquid crystal cell and between the second polarizer and the liquid crystal cell . In addition, they may be provided on both surfaces of the first polarizing plate and the second polarizing plate, respectively.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are for illustrative purposes only and are not intended to limit the scope of the invention by the following examples.

≪ Example 1 >

The polyamide resin (Evonik CX7323, Semi-crystal, Tg 133 캜) was melt-mixed at 260 캜 using an extruder including a T-die to prepare an unoriented film having a thickness of 50 탆.

≪ Example 2 >

A polyamide resin (Evonik CX9704, Amorphous, Tg 130 ° C) was melt-mixed at 260 ° C using an extruder including a T-die to prepare an unoriented film having a thickness of 50 μm.

≪ Comparative Example 1 &

Triacetylcellulose system (UZ TAC, Fuji) A 60 탆 thick undrawn film was used to measure the physical properties.

<Experimental Example 1>

In the examples of the present invention, the physical property evaluation method is as follows, and the results are shown in Table 1 below.

1. Water vapor permeability: A method of measuring the weight of water permeating the film for 24 hours under conditions of a temperature of 40 ° C and a relative humidity of 90% was used.

2. Transmittance: The transmittance of light according to the wavelength of 550 nm was measured using U-3310 (Hitachi).

3. Toughness: Measured using Impact Energy (IE), a drop impact tester (Withlab) was used to drop 130 or 218 grams of iron ball into the film to break the film And the impact energy per film unit volume was calculated from the following equation (3).

&Quot; (3) &quot;

Impact Energy = Gravity Acceleration X Weight of Diameter X Height / (Film Thickness X Film Area)

4. Haze and light transmittance: Measured according to the ASTM 1003 method.

5. Phase difference value (Rth / Rin): The retardation (Rin) in the plane direction and retardation (Rth) in the thickness direction of the prepared optical film were measured using an Axoscan equipment (Axometrics).

division Moisture permeability
(g / m ² · day) Shock energy
kN · m / m ³ Permeability
(%) Hayes Rin (nm) Rth (nm) Example 1 28 5520 92 0.3 4 -8 Example 2 29 4120 92 0.3 2 -7 Comparative Example 1 262 3057 92 0.3 3 -47

As shown in the above Table 1, the polarizer protective film of the present invention is excellent in optical properties, such as having a numerical value suitable for use as a protective film in terms of transmittance, haze, and retardation value, It was found that the water vapor permeability was very low, the impact energy value was remarkably high, and the toughness was also excellent.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be obvious to those of ordinary skill in the art.

Claims (10)

A polyamide resin comprising a unit represented by the following formula (1) or (2)
(R _in ) defined by the following formula (1) is -10 nm to 10 nm,
The thickness direction retardation (R _th ) value defined by the following formula (2) is -10 nm to 10 nm,
A thickness of 5 탆 to 80 탆,
The moisture permeability is more than 0 and less than 140 g / m ² day,
Polarizer protective film having a unit transmittance of 90% or more and less than 100%.
&Quot; (1) &quot; R _in = (n _x - n _y ) x d,
&_Quot; (2) &quot; R _th = (n _z - n _y ) x d
In the above equations (1) and (2)
n _x is the largest refractive index among the refractive indices in the plane direction of the film,
n _y is a refractive index in a direction perpendicular to n _{x of the} refractive index in the plane direction of the film,
n _z is the refractive index in the thickness direction,
d is the thickness of the film,
[Chemical Formula 1]

Wherein A is a C _2-16 aliphatic hydrocarbon chain or a C _5-14 aliphatic hydrocarbon ring, X ₁ is a halogen atom or a C _1-6 alkyl group, a is an integer of 0 to 3, n is 5 &Lt; / RTI &gt;
(2)

In Formula 2, B and C are each independently a C _2-16 aliphatic hydrocarbon chain or a C _5-14 aliphatic hydrocarbon ring, X ₂ and X ₃ are each independently a halogen atom or a C _1-6 alkyl group, b And c are each independently an integer of 0 to 3, and m is an integer of 5 to 10,000. delete delete The method according to claim 1,
Wherein the polyamide based resin has a weight average molecular weight of 1,000 to 300,000.
delete delete The method according to claim 1,
Wherein an impact energy at which breakage of the polarizer protective film is started is 1000 kN · m / m ³ or more and 5520 kN · m / m ³ or less. delete A polarizer comprising the polarizer protective film of any one of claims 1, 4 and 7. A liquid crystal display device comprising the polarizer protective film of any one of claims 1, 4, and 7.