TW201606026A - Adhesive composition and polarizing plate comprising the same - Google Patents

Abstract

The present invention provides an adhesive composition comprising a polyester resin and a cross-linking agent, a polarizing plate and a liquid crystal display device comprising the adhesive composition. The adhesive composition for a polarizing plate according to the present invention can allow good adhesion of a polarizer and a protective film having poor adhesiveness, such as polymethyl methacrylate, polypropylene and triacetyl cellulose films.

Description

Adhesive composition and polarizing plate containing the same

The present invention relates to an adhesive composition for a polarizing plate which has excellent adhesion to a protective film which is difficult to adhere, and a polarizing plate and a liquid crystal display device comprising the adhesive composition.

The polarizing plate generally has a multilayer structure including a polarizer composed of a polyvinyl alcohol-based resin in which a dichroic pigment is adsorbed and aligned; and a transparent protective film laminated on one or both surfaces of the polarizer. The polarizer is obtained by subjecting a polyvinyl alcohol-based resin film to vertical uniaxial stretching, dyeing the stretched film with a dichroic pigment, treating the dyed film with an aqueous boric acid solution, and washing and drying the treated film. The dichroic pigment can be an iodine or a dichroic organic dye. The polarizer thus obtained is laminated on one or both surfaces thereof to prepare a polarizing plate, and the polarizing plate is introduced into the liquid crystal display device.

The protective film is mostly made of cellulose and is known to have a thickness of 30 to 120 μm. Further, a protective film is laminated using an adhesive composed of an aqueous solution of a polyvinyl alcohol-based resin.

However, the cellulose-based film should be saponified (treated with a base) on the surface to which the adhesive is bonded to the polarizer. A UV adhesive capable of bonding a cellulose-based film to a polarizer without saponification has been proposed, however, its adhesive strength is lower than that of an aqueous adhesive, causing cracks in the polarizer in a thermal shock test. In addition, UV adhesives are very expensive and not Ji.

In addition, cellulose-based films have poor heat and water repellency properties, thereby reducing the effectiveness of the polarizing plate or causing separation of the protective film from the polarizer. For this reason, various resins (acrylate or acryl resin) other than the cellulose-based film have been tried as a protective film on at least one side of the polarizer.

However, a conventional water-based adhesive composed of an aqueous solution of a polyvinyl alcohol-based resin has low adhesion to an acrylate protective film (see Korean Patent Application Laid-Open No. 2010-0095402).

An object of the present invention is to provide an adhesive composition for a polarizing plate which has excellent adhesion to a protective film which is difficult to adhere.

Another object of the present invention is to provide a polarizing plate comprising an adhesive layer formed of an adhesive composition.

It is still another object of the present invention to provide a liquid crystal display device comprising a polarizing plate.

According to an aspect of the present invention, an adhesive composition comprising a polyester resin and a crosslinking agent is provided.

In one embodiment of the present invention, the polyester resin may be a water-soluble polyester resin having a sulfonic acid, a sulfonate, a carboxylic acid or a carboxylate as a functional group.

In one embodiment of the present invention, the polyester resin can be produced by polymerization of an aromatic dicarboxylic acid having a sulfonic acid, a sulfonate, a carboxylic acid or a carboxylate as a functional group with an aliphatic diol.

In one embodiment of the present invention, the polyester resin may be a polymer having one or more selected from the group consisting of the repeating units of the formulae (I) and (II):

Wherein R is a sulfonic acid, a sulfonate, a carboxylic acid or a carboxylate; and n is an integer from 1 to 10.

In one embodiment of the invention, the polyester resin may have a molecular weight of 10,000 to 40,000.

In one embodiment of the present invention, the crosslinking agent may be present in an amount of from 50 to 400 parts by weight based on 100 parts by weight of the polyester resin.

According to another aspect of the present invention, there is provided a polarizing plate comprising a polarizer; an adhesive layer laminated on one or both surfaces of the polarizer and formed of the adhesive composition; and laminated on the A polarizer protective film on the adhesive layer.

According to still another aspect of the present invention, a liquid crystal display device including the polarizing plate is provided.

The adhesive composition for a polarizing plate according to the present invention can allow the polarizer to adhere well to a protective film having poor adhesion such as polymethyl methacrylate, polypropylene, and unsaponified triacetyl cellulose film.

The invention is described in more detail below.

One embodiment of the present invention relates to an adhesive composition comprising a polyester resin and a crosslinking agent.

In one embodiment of the present invention, the polyester resin may have a sulfonic acid, a sulfonate, A water-soluble polyester resin having a carboxylic acid or a carboxylate as a functional group.

The sulfonate can be a metal salt of a sulfonic acid such as a sodium salt and a potassium salt, an ammonium salt or an organic amine salt. Among them, a sodium salt of a sulfonic acid is preferred.

The carboxylate can be a metal salt of a carboxylic acid such as a sodium salt and a potassium salt, an ammonium salt or an organic amine salt. Among them, a sodium salt of a carboxylic acid is preferred.

In one embodiment of the present invention, the polyester resin can be produced by polymerization of an aromatic dicarboxylic acid having a sulfonic acid, a sulfonate, a carboxylic acid or a carboxylate as a functional group with an aliphatic diol.

The aromatic dicarboxylic acid may be terephthalic acid, isophthalic acid or naphthalene dicarboxylic acid, but is not limited thereto. These acids may be used singly or in combination of two or more.

The aliphatic diol may be ethylene glycol, 1,4-butanediol or 1,3-propanediol, but is not limited thereto. These diols may be used singly or in combination of two or more.

In one embodiment of the present invention, the polyester resin may be a polymer having one or more selected from the group consisting of the repeating units of the formulae (I) and (II):

Wherein R is a sulfonic acid, a sulfonate, a carboxylic acid or a carboxylate; and n is an integer from 1 to 10.

Examples of the commercially available polyester resin may include a water-soluble polyester resin having a sulfonate functional group such as Z-446, Z-221, Z-561, and Z-565 (GOO CHEMICAL), but are not limited thereto.

The molecular weight of the polyester resin is not particularly limited, but it is preferably in the range of 10,000 to 40,000 Inside to provide excellent adhesion between the polarizer and the protective film. If the molecular weight is less than 10,000, it is difficult to provide sufficient adhesion. If the molecular weight is above 40,000, air bubbles can be entrained during the bonding process.

In one embodiment of the invention, the crosslinking agent is used to enhance durability and adhesion between the polarizer and the protective film and to maintain reliability at high temperatures and in the form of an adhesive.

The crosslinking agent may include an isocyanate compound, an epoxy compound, a peroxy compound, a metal chelate compound, an oxazoline compound, a melamine compound, a glyoxylate compound, an aziridine compound, or the like. These compounds may be used singly or in combination of two or more. Among them, an aziridine compound is preferred depending on the adhesion and durability.

Hereinafter, the aziridine crosslinking agent as a preferred crosslinking agent will be described in detail, but the invention is not limited thereto.

The aziridine crosslinker can react with a functional group such as a hydrophilic group on the surface of the membrane via an aziridine functional group, and it can be used in an adhesive composition to reduce the surface energy of the film, thereby providing sufficient wettability to Non-polar film, such as an acrylate film. Therefore, the adhesive composition containing an aziridine crosslinking agent exhibits high adhesion even to a film having a low surface energy and having a rough surface. Further, the aziridine crosslinking agent can be subjected to ring opening to form a hydrophilic group via ring opening. The hydrophilic group may be hydrogen bonded to a hydroxyl group on the surface of an optical film such as a polarizer. To this end, the aziridine crosslinker provides excellent adhesion compared to conventional adhesives such as polyvinyl alcohol adhesives. In addition, the polyfunctional aziridine compound enhances the cohesive effect in the adhesive layer, thereby preventing entrainment of bubbles and enhancing waterproof properties.

Preferred examples of the aziridine crosslinking agent may include pentaerythritol-gin-(β-N-aziridine)propionate, trimethylolpropane-gin-(β-N-aziridine group). Propionate and trimethylolpropane-gin-(2-methyl-1-aziridine propionate). Among them, trimethylolpropane-gin-(2-methyl-1-aziridine propionate) is more preferable depending on the adhesion efficiency.

The content of the crosslinking agent may be present in an amount of from 50 to 400 parts by weight, preferably from 100 to 300 parts by weight, based on 100 parts by weight of the solid content of the polyester resin. The amount of crosslinker is less than 50 weight When it is used, it is difficult to make the protective film with poor adhesion adhere to it. When the amount of the crosslinking agent exceeds 400 parts by weight, liquid stability may be lowered.

The adhesive composition according to an embodiment of the present invention may further comprise an organic solvent to provide high wetting characteristics between the polarizer and the protective film, and an alcohol is preferred as the organic solvent.

The function of the alcohol is to dissolve the surface of the protective film having poor adhesion so that the components of the adhesive composition penetrate to the surface of the protective film and cause a chemical reaction. Therefore, entrainment of air bubbles can be prevented. Further, the alcohol has excellent wetting characteristics for a protective film having poor adhesion, thereby providing a leveling agent.

Examples of the alcohol which can be used in the present invention include methanol, ethanol, propanol, isopropanol, butanol, tert-butanol, and glycerin. These alcohols may be used singly or in combination of two or more. The content of the alcohol may be from 3 to 30 parts by weight based on 100 parts by weight of the solid content of the polyester resin. If the amount of the alcohol is less than 3 parts by weight, the peel strength may be lowered. If the amount of alcohol exceeds 30 parts by weight, it exceeds the critical concentration of the explosion limit and requires explosion-proof equipment.

The adhesive composition according to one embodiment of the present invention may further comprise additives such as a plasticizer, a decane coupling agent, an antistatic agent, a fine particle, and a leveling agent within a range not degrading the intended action of the present invention. In particular, a leveling agent is preferably used to improve the spreading characteristics of the adhesive composition.

The adhesive composition according to an embodiment of the present invention is preferably in a liquid form to uniformly form an adhesive layer on the surface of the adhered polarizer or protective film. The liquid adhesive can be a solution or dispersion in various solvents. A solution is preferred depending on the processability of the coating on the substrate, and a solution or dispersion in water is preferred depending on the stability.

Further, in order to shorten the drying time, a mixed solvent of water and an alcohol having excellent water miscibility and having a boiling point lower than water may be used. Preferred alcohols have a boiling point of no more than 100 ° C, especially no more than 80 ° C or no more than 70 ° C.

One embodiment of the invention relates to a polarizing plate comprising a polarizer; lamination An adhesive layer formed on one or both surfaces of the polarizer and formed of an adhesive composition; and a polarizer protective film laminated on the adhesive layer.

In one embodiment of the invention, the polarizer is obtained by adsorbing and aligning the dichroic pigment onto the stretched polyvinyl alcohol film.

The polyvinyl alcohol resin constituting the polarizer can be obtained by saponifying a polyvinyl acetate resin. The polyvinyl acetate resin may be a polyvinyl acetate which is a homopolymer of vinyl acetate or a copolymer of vinyl acetate and other monomers copolymerizable with vinyl acetate. Other examples of the monomer copolymerizable with vinyl acetate may include an unsaturated carboxylic acid, an unsaturated sulfonic acid, an olefin, a vinyl ether, and an ammonium group-containing acrylamide monomer. Further, the polyvinyl alcohol resin can be modified, for example, a polyvinyl formal or a polyvinyl acetal is modified with an aldehyde. The degree of saponification of the polyvinyl alcohol resin is conventionally in the range of 85 to 100 mol%, preferably 98 mol% or more. Further, the degree of polymerization of the polyvinyl alcohol resin is conventionally found in the range of 1,000 to 10,000, preferably 1,500 to 5,000.

Such polyvinyl alcohol resins are obtained in the form of a film which is used as an original film of a polarizer. The method of forming a film from a polyvinyl alcohol resin can be carried out according to, but not limited to, various known methods. The original film may have a thickness of 10 to 150 μm, but is not limited thereto.

The continuous method of the polarizer of the present invention is to uniaxially stretch a polyvinyl alcohol film in an aqueous solution, dye the stretched film with a dichroic pigment, treat the dyed film with an aqueous solution of boric acid, and wash and dry the treated film.

The uniaxial stretching of the polyvinyl alcohol film can be carried out before, during or after the dyeing. If uniaxial stretching is carried out after dyeing, it can be carried out before or during treatment with boric acid. Of course, uniaxial stretching can be carried out in a multi-stage manner. In the uniaxial stretching, a drum having a different speed or a heating roller can be used. The uniaxial stretching may be a dry stretching performed in the atmosphere or a wet stretching in a state of being expanded in a solvent. The stretching ratio of the polyvinyl alcohol film is conventionally in the range of 4 to 8 times.

For example, by immersing a polyvinyl alcohol film in an aqueous solution containing a dichroic pigment, The drawn polyvinyl alcohol film is dyed with a dichroic pigment. The dichroic pigment can be iodine or a dichroic dye. Further, the polyvinyl alcohol film is preferably pre-immersed in water for expansion before dyeing.

When iodine is used as the dichroic pigment, the dyeing is conventionally carried out by immersing the polyvinyl alcohol film in a dyeing solution containing iodine and potassium iodide. In the dyeing solution, iodine is conventionally present in an amount of 0.01 to 1 part by weight based on 100 parts by weight of water (distilled water), and potassium iodide is conventionally present in an amount of 0.5 to 20 parts by weight based on 100 parts by weight of water. The temperature of the dyeing solution is conventionally in the range of 20 ° C to 40 ° C, and the immersion time (dyeing time) is conventionally in the range of 20 to 1,800 seconds.

When a dichroic dye is used as the dichroic pigment, dyeing can be carried out by immersing the polyvinyl alcohol film in an aqueous solution containing a water-soluble dichroic dye. In the aqueous solution, the dichroic dye is conventionally present in an amount of from 1 × 10 ^-4 to 10 parts by weight, preferably from 1 × 10 ^-3 to 1 part by weight, per 100 parts by weight of water. The aqueous solution may further contain an inorganic salt such as sodium sulfate as a dyeing aid. The temperature of the aqueous solution dyeing is conventionally in the range of 20 ° C to 80 ° C, and the immersion time is conventionally in the range of 10 to 1,800 seconds.

The dyed polyvinyl alcohol film can be treated with boric acid by immersing the film in an aqueous boric acid solution. In the aqueous boric acid solution, boric acid is conventionally present in an amount of from 2 to 15 parts by weight, preferably from 5 to 12 parts by weight, per 100 parts by weight of water. When iodine is used as the dichroic pigment, the aqueous boric acid solution conventionally contains potassium iodide in an amount of 0.1 to 15 parts by weight, preferably 5 to 12 parts by weight, per 100 parts by weight of water. The temperature of the aqueous boric acid solution is conventionally 50 ° C or more, preferably 50 ° C to 85 ° C, more preferably 60 ° C to 80 ° C, and the immersion time is conventionally 60 to 1,200 seconds, preferably 150. It is in the range of 600 seconds, more preferably 200 to 400 seconds.

After treatment with boric acid, it is conventional to wash and dry the polyvinyl alcohol film. Washing can be carried out by immersing the boric acid-treated polyvinyl alcohol film in water. In the washing step, the water temperature is conventionally in the range of 5 to 40 ° C, and the immersion time is conventionally in the range of 1 to 120 seconds. The washed polyvinyl alcohol film was dried to obtain a polarizer. Drying can be carried out using a hot air dryer or a far infrared heater. The drying temperature is conventionally in the range of 30 ° C to 100 ° C, preferably 50 ° C to 80 ° C, and the drying time is conventionally in the range of 60 to 600 seconds, preferably 120 to 600 seconds.

Polarizers are known to have a thickness of 5 to 40 μm.

In one embodiment of the present invention, the polarizer protective film is not particularly limited as long as it has excellent transparency, mechanical strength, thermal stability, moisture resistance, and isotonicity. In particular, acrylate, cellulose, polyolefin, and polyester films can be used.

Specifically, for the protective film, an acrylate resin such as poly(methyl) methacrylate and poly(ethyl) acrylate; a polyester resin such as polyethylene terephthalate or polyisophthalate may be used. Ethyl diacetate, ethyl polyethylene naphthalate and polybutylene terephthalate; cellulose resins such as diethyl cellulose and triethyl cellulose; and polyolefin resins such as polyethylene , polypropylene, polyolefin having a cyclic or norbornene structure, and an ethylene-propylene copolymer.

The polarizer protective film may have a thickness of 10 to 200 μm, preferably 10 to 150 μm. Further, in the case where the polarizer protective film is formed on both surfaces of the polarizer, they may have the same or different thicknesses.

The surface of the protective film bonded to the polarizer can be subjected to treatment for easy bonding, such as dry treatment such as primer treatment, plasma treatment, and corona treatment, chemical treatment such as alkali treatment (saponification), or coating to form an easy adhesion layer. deal with.

Specifically, in the present invention, a protective film which is not subjected to a chemical treatment such as alkali treatment (saponification), for example, an unsaponified cellulose protective film is also easily bonded to a polarizer. Therefore, the present invention does not require such a process.

In addition to the unsaponified cellulose protective film, it is subjected to dry treatment on the surface of an acrylate or propylene protective film which is a representative protective film having poor adhesion, and can be easily joined to a polarizer.

The adhesive layer generally has a thickness of from 0.01 to 10 μm, preferably from 0.05 to 5 μm, more preferably from 0.1 to 1 μm. The surface of the protective film that is not in contact with the polarizer can be treated for hard coating, anti-reflection, anti-sticking, diffusion or anti-glare.

Bonding can be carried out by conventional methods known in the art, for example using casting, Meyer bar coating, gravure coating, slit coating, dip coating, and spraying apply the adhesive composition to the surface of the polarizer or protective film to be joined, followed by bonding. Applying an adhesive composition on the surface of the polarizer or protective film to be joined by means of the adhesive composition while moving the polarizer or the protective film in an oblique direction between the vertical or horizontal direction or between the two directions, applying the adhesive composition The object is cast. After the application of the adhesive composition, the polarizer or protective film is inserted into the nip roller and the like to be joined.

After the polarizer is bonded to the protective film, the drying treatment can be performed, for example, by spraying hot air. The drying temperature can be appropriately selected within the range of 40 to 100 ° C, preferably 60 to 100 ° C. The drying time can be in the range of 20 to 1,200 seconds. After the drying treatment, the curing is preferably carried out at room temperature or slightly above room temperature, for example, at a temperature of 20 to 50 ° C for 12 to 600 hours. The dried adhesive layer generally has a thickness of from 0.001 to 5 μm, preferably from 0.01 to 2 μm, more preferably from 0.01 to 1 μm. If the thickness of the adhesive layer is higher than 5 μm, it may cause appearance defects of the polarizer.

The other surface of the polarizer that does not contact the protective film may further have a surface treatment layer thereon, such as a hard coat layer, an antireflection layer, an antiglare layer, and an antistatic layer. Furthermore, the optically functional layer can be further laminated thereon by means of a reusable adhesive layer. Examples of the optical functional layer may include an optical compensation film having a liquid crystal compound or a polymer thereof aligned on a surface of a substrate, a reflective polarization separation film that transmits one polarized light and reflects polarized light of the opposite kind, and a retardation including a polycarbonate resin A film, a retardation film comprising a cyclic polyolefin resin, an anti-glare film having an uneven surface, an anti-reflection film, a reflective film having a reflective function, and a transflective film having a reflective function and a transmissive function.

One embodiment of the present invention relates to a liquid crystal display device including the polarizing plate.

The invention is further illustrated by the following examples, comparative examples and experimental examples, which should not be construed as limiting the scope of the invention.

Preparation Example 1: Preparation of a polarizer

A polyvinyl alcohol film having an average degree of polymerization of 75 μm and an average degree of polymerization of 2,400 and a degree of saponification of 99.9 mol% or more than 99.9 mol% was subjected to dry uniaxial stretching for about 5 times. While maintaining the film stretched state, the film was immersed in 60 ° C water (distilled water) for 1 minute, and then immersed in an aqueous solution of iodine / potassium iodide / water (0.05 / 5 / 100, weight ratio) and adjusted to 28 °C, lasts 60 seconds. Next, the membrane was immersed in an aqueous solution of potassium iodide/boric acid/distilled water (8.5/8.5/100, weight ratio) at 72 ° C for 300 seconds, washed with distilled water of 26 ° C for 20 seconds and dried at 65 ° C to obtain iodine adsorption and alignment. A polarizer on a polyvinyl alcohol film.

Examples 1 to 12 and Comparative Example 1: (1) Preparation of an adhesive composition for a polarizing plate

Each of the adhesive compositions for the polarizing plate was prepared by mixing the components with the compositions listed in Table 1 (based on the solid content).

(2) Preparation of polarizing plate

The adhesive composition was applied to the iodine prepared in Preparation Example 1 and adsorbed on both surfaces of the polarizer on the polyvinyl alcohol film so that the dried layer had a thickness of 0.1 μm, and then the nip roller was used. A corona-treated poly(methyl) methacrylate protective film is laminated thereon. The laminate was dried in a hot air dryer at 80 ° C for 5 minutes to produce a polarizing plate.

Z-446 and Z-221 (GOO CHEMICAL): polyester resin

CL-427(MENADIONA): Isovalerol-para-(β-N-aziridine)propionate

CX-100 (DSM): Trimethylolpropane-gin-(2-methyl-1-aziridine propionate)

Alcohol (Aldrich)

Polyvinyl alcohol resin (Cosenol Z200, Nippon Synthetic Chemical Industry)

Experimental Example 1: Evaluation of Adhesion and Peel Strength

The physical properties of the polarizing plates prepared in the examples and comparative examples were measured using the following methods, and the results are shown in Table 2.

(1) Adhesiveness (using a cutting machine)

The prepared polarizing plate was left at room temperature for 1 hour, and then the blade of the cutter was inserted between the films of the polarizing plate (between the polarizer and the protective film) and the degree of advancement of the blade was observed while pushing the blade.

<Evaluation criteria>

◎: The cutter blade does not enter between any membranes

○: the cutter blade moves 1 to 2 mm into at least one interface between the films, and then terminates

△: the cutter blade moves 3 to 5 mm into at least one interface between the films, and then terminates

×: The cutter blade smoothly moves to at least one interface between the films

(2) Peel strength

The prepared polarizing plate was left at room temperature for 1 hour, and then attached to the soda glass with a re-use adhesive using a hand roller. After treatment in an autoclave at 50 ° C and 2 atm for 20 minutes, the bubbles generated during the attachment were removed. In a laminate of soda glass/reusable adhesive/acrylate polarizer, a knife is inserted between the polarizer and the corona-treated acrylate protective film in the direction of the soda glass, and the peel strength is measured by using AUTOGRAPH. The peel rate of 300 mm/min and the peel angle of 180° were measured from the adhesive layer peeling polarizer.

As shown in Table 2, the adhesive compositions of Examples 1 to 12 containing the polyester resin according to the present invention showed remarkably excellent adhesiveness and peel strength as compared with Comparative Example 1 containing a polyvinyl alcohol resin.

While the invention has been shown and described with respect to the embodiments of the present invention, it will be understood that Make various changes and modifications.

Accordingly, the scope of the invention is defined by the scope of the appended claims and their equivalents.

Claims (14)

An adhesive composition comprising a polyester resin and a crosslinking agent. The adhesive composition of claim 1, wherein the polyester resin is a water-soluble polyester resin having a sulfonic acid, a sulfonate, a carboxylic acid or a carboxylate as a functional group. The adhesive composition of claim 2, wherein the sulfonate is a sodium salt of a sulfonic acid. The adhesive composition of claim 1, wherein the polyester resin is prepared by polymerization of an aromatic dicarboxylic acid having a sulfonic acid, a sulfonate, a carboxylic acid or a carboxylate as a functional group with an aliphatic diol. The adhesive composition of claim 4, wherein the aromatic dicarboxylic acid is at least one selected from the group consisting of terephthalic acid, isophthalic acid, and naphthalene dicarboxylic acid. The adhesive composition of claim 4, wherein the aliphatic diol is at least one selected from the group consisting of ethylene glycol, 1,4-butanediol, and 1,3-propanediol. The adhesive composition of claim 1, wherein the polyester resin is a polymer having one or more selected from the group consisting of the repeating units of the formulae (I) and (II): Wherein R is a sulfonic acid, a sulfonate, a carboxylic acid or a carboxylate; and n is an integer from 1 to 10. The adhesive composition of claim 1, wherein the polyester resin has a molecular weight of 10,000 to 40,000. The adhesive composition of claim 1, wherein 100 parts by weight of the polyester resin is used, The crosslinking agent is present in an amount of from 50 to 400 parts by weight. The adhesive composition of claim 1, which further comprises an alcohol. The adhesive composition of claim 10, wherein the alcohol is present in an amount of from 3 to 30 parts by weight based on 100 parts by weight of the polyester resin. A polarizing plate comprising: a polarizer; an adhesive layer laminated on one or both surfaces of the polarizer and formed of the adhesive composition according to any one of claims 1 to 11; and laminated thereon A polarizer protective film on the adhesive layer. The polarizing plate of claim 12, wherein the polarizer protective film is an acrylate, cellulose, polyolefin or polyester film. A liquid crystal display device comprising the polarizing plate of claim 12.