KR20160088064A - Polarizing plate and image display device comprising the same - Google Patents

Abstract

The present invention relates to a polarizing plate, and an image display device having the same. More specifically, the present invention relates to a polarizing plate having a protective layer formed in at least one surface of a polarizer, and including an adhesive layer in an outer surface of the protective layer. The polarizing plate fixates a first vertex part of the polarizing plate, and reverses and fixates a second vertex part where a side of the polarizer in a transverse direction (TD) is connected to the first vertex so as to enable load (X) where a rupture is generated in the polarizing plate and adhesion (Y) of the adhesive layer to satisfy a specific mathematics formula when the load is applied in the TD, thereby having excellent reworkability.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polarizing plate and an image display device including the polarizing plate.

This technology relates to a polarizing plate having excellent reworkability and an image display device including the same.

The liquid crystal display device includes a liquid crystal display panel for displaying an image using light and a backlight assembly for providing light to the liquid crystal display panel, and a polarizing plate for polarizing light is provided on the upper and lower portions of the liquid crystal display panel, respectively.

The polarizing plate provided at the lower part of the liquid crystal display panel polarizes the light from the backlight assembly to the liquid crystal display panel, and the polarizing plate provided thereon polarizes the light from the liquid crystal display panel.

Such a polarizer is defective such as an alignment error with the liquid crystal display panel, or is removed from the liquid crystal display panel when the liquid crystal display panel is subjected to a rewet process.

In recent years, polarizers are becoming thinner in order to reduce cost and improve reliability. In such a case, the polarizer is not completely separated from the liquid crystal display panel in the process of separating the polarizer and the liquid crystal display panel.

In addition, the polarizing plate may be torn in the rework process depending on the angle of separation between the polarizing plate and the liquid crystal display panel. However, since the separation angle at which the tearing of the polarizing plate occurs varies depending on the material of the polarizing plate, there is a problem that it is difficult to adjust the separation angle.

In order to prevent this, there is a method of softening or melting and peeling the adhesive while inserting heated heating wire or slicer between the liquid crystal panel and the optical film, a method of applying an additional film to reinforce the thickness of the polarizing plate, a method of reducing the adhesive force of the polarizing plate, And a method of reducing the peeling speed. However, the above methods require a separate process or an increase in the process time, and a load is generated in the polarizing plate during the process of repeated shrinkage and expansion of the polarizing plate due to a change in the surrounding environment, so that light leakage occurs at the edge of the polarizing plate And the like.

Japanese Patent Application Laid-Open No. 2001-242448 discloses a polarizing plate peeling method capable of maintaining the uniformity of substrate spacing of the glass substrate and preventing occurrence of contrast unevenness even if the polarizing plate is peeled from the surface of the liquid crystal cell, We did not offer an alternative to a problem.

Japanese Patent Application Laid-Open No. 2001-242448

An object of the present invention is to provide a polarizing plate having excellent reworkability.

1. A polarizing plate comprising a polarizer and a protective layer formed on at least one surface of the polarizer and including an adhesive layer on an outer surface of the protective layer, wherein a first vertex portion of the polarizer is fixed, When the second vertex portion is turned upside down and the load is applied in the TD direction,

Wherein a load (X) causing breakage in the polarizing plate and an adhesive force (Y) of the pressure-sensitive adhesive layer satisfy the following formula (1)

[Equation 1]

Y? 0.06X + 2.4

(Wherein X is 15 to 200 N).

2. The polarizing plate according to item 1, wherein the polarizing plate has a load X of 15 to 150 N at which fracture occurs.

3. The polarizing plate according to item 1 above, wherein the protective layer is a protective film.

4. The polarizer of claim 1, wherein the protective layer comprises a hard coat layer.

5. The polarizer of claim 4, wherein the hard coat layer is formed from a composition comprising a binder resin, a polymerizable monomer, a polymerization initiator, and a solvent.

6. The composition according to 5 above, wherein said composition comprises 10 to 30 parts by weight of a binder resin, 5 to 30 parts by weight of a polymerizable monomer, 1 to 25 parts by weight of a polymerization initiator and 30 to 80 parts by weight of a solvent, , A polarizer.

7. An image display device comprising any one of the polarizing plates 1 to 6 above.

In the polarizing plate of the present invention, the load at which the polarizing plate is broken and the adhesive force of the adhesive layer satisfy a certain formula, so that even if the adhesive force is increased, the polarizing plate is excellent in reheat property without causing breakage.

1 is a view schematically showing a method of measuring a load in which a polarizing plate according to the present invention is broken.
Fig. 2 is a view schematically showing a method for evaluating the reworkability of a polarizing plate according to the present invention.

A polarizing plate comprising a polarizer and a protective layer formed on at least one surface of the polarizer and including an adhesive layer on the outer surface of the protective layer, wherein the polarizer has a first vertex portion fixed, and a second polarizer TD connected to the first vertex The load X causing the polarizing plate to be broken and the adhesive force Y of the adhesive layer satisfy a specific formula when the load is applied in the TD direction by fixing the second vertex portion where the second vertex is located, An excellent polarizing plate and an image display apparatus including the same.

Hereinafter, the present invention will be described in detail.

Polarizer

The pressure-sensitive adhesive for bonding the polarizing plate to the liquid crystal panel is closely related to the rework characteristic of the polarizing plate. When the low-pressure adhesive is used for the ease of rework, the durability of the polarizing plate deteriorates. In order to improve durability, There is a problem that breakage of the polarizing plate occurs during reworking.

On the other hand, the breakage of the polarizing plate is also related to the strength of the polarizing plate, so that the weaker the polarizing plate, the easier it is to break. However, if the strength of the polarizing plate is excessively increased, the flexibility of the polarizing plate may deteriorate or the adhesive strength between the polarizing plate and another substrate may deteriorate.

Therefore, it is important to control the adhesive strength of the polarizer and the adhesive used for bonding the polarizer and the liquid crystal panel in order to prevent the polarizer from breaking and improve the workability.

The present invention relates to a method for manufacturing a polarizing plate in which a protective layer is formed on at least one surface of a polarizer, and a protective layer is formed on at least one surface of the polarizer, And a pressure-sensitive adhesive layer on the outer surface of the protective layer, wherein a first edge of the polarizer is fixed, a second edge of the polarizer facing the direction of the polarizer connected to the first edge is fixed, The present invention provides a polarizing plate excellent in reworkability by satisfying a formula (X) in which a fracture occurs in the polarizing plate and an adhesive force (Y) of the adhesive layer satisfy a specific formula.

Specifically, the load (X) causing the polarizing plate to break and the adhesive force (Y) of the adhesive layer satisfy the following formula (1).

[Equation 1]

Y? 0.06X + 2.4

In the formula, X means a load in which a break occurs in the polarizing plate when a load is applied in the TD direction, and Y means adhesive force of the adhesive layer. In the above formula (1), X is 15 to 200N.

When the above formula (1) is not satisfied, the reworkability of the polarizing plate is lowered, and the polarizing plate is broken at the time of rewiring of the polarizing plate.

On the other hand, when X is less than 15, the polarizing plate tends to be torn or durability is weak. When X exceeds 200, it is not easy to produce a polarizing plate having such a load.

In the above formula (1), X may preferably be 15 to 150N.

In the present specification, the load X causing the polarizing plate to break is defined as a direction in which the first vertex portion of the polarizing plate is fixed, and the second vertex portion which is opposite to the polarizer TD direction connected to the first vertex is inverted and fixed, Means a load in which the polarizing plate is broken.

A method of measuring the load at which the polarizing plate according to the present invention is broken is schematically shown in Fig. Specifically, referring to FIG. 1, first, a first vertex portion of a polarizing plate is fixed (a). The method of fixing the vertex portion is not particularly limited, and for example, a clip, a clamp, or the like can be used. Next, the second vertex portion where the sides of the coupled polarizer TD connected to the first vertex portion meet is fixed upside down (b, c). After the second vertex portion is inverted and fixed, a load is applied in a direction (TD) connecting the first vertex and the second vertex (d).

The adhesive force (Y) is a force generated by the adhesive layer included in the polarizing plate according to the present invention. When the polarizing plate according to the present invention is applied to another substrate, for example, a liquid crystal panel, a force acting between the polarizing plate and the liquid crystal panel It says.

The pressure-sensitive adhesive layer is generally used in the art, and the pressure-sensitive adhesive layer is not limited as long as it does not deviate from the object of the present invention. Specific examples thereof include rubber-based pressure-sensitive adhesives, acrylic pressure sensitive adhesives and silicone pressure sensitive adhesives.

The polarizing plate according to the present invention can be manufactured by setting the load (X) at which breakage occurs and the adhesive force (Y) of the adhesive layer to satisfy Equation (1), and the load can be controlled by controlling the stretching ratio, thickness, Materials and the like, and the adhesive strength of the adhesive layer can be adjusted by varying the composition or composition of the adhesive, but is not limited thereto.

Polarizer

The polarizer may be obtained by swelling, dyeing, crosslinking, stretching, washing with water, and drying the polarizer-forming film ordinarily used in the art.

The polarizer according to the present invention may be a polarizer commonly used in the art, which is produced according to a process including a step of swelling, dyeing, crosslinking, stretching, washing, drying, and the like.

The type of the polarizer-forming film is not particularly limited as long as it is a dichroic substance, that is, a film which can be dyed with iodine. Examples thereof include a polyvinyl alcohol film, a dehydrated polyvinyl alcohol film, a dehydrochlorinated polyvinyl alcohol film, Polyethylene terephthalate film, ethylene-vinyl acetate copolymer film, ethylene-vinyl alcohol copolymer film, cellulose film, partially saponified film thereof and the like. Of these, a polyvinyl alcohol-based film is preferable because it has an excellent effect of enhancing the uniformity of the degree of polarization in the plane and is excellent in dye affinity for iodine.

The polyvinyl alcohol-based resin is obtained by saponifying a polyvinyl acetate-based resin. Examples of the polyvinyl acetate resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate and other monomers copolymerizable therewith.

Other monomers copolymerized with vinyl acetate are generally used in the art and are not limited as long as they do not deviate from the object of the present invention. Specific examples thereof include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, For example.

The modified polyvinyl alcohol resin may be a modified polyvinyl alcohol resin. Specific examples thereof include polyvinyl formal and polyvinyl acetal modified with aldehydes.

The degree of saponification of the polyvinyl alcohol-based resin may be 85 to 100 mol%, preferably 98 to 100 mol%, and the degree of polymerization of the polyvinyl alcohol-based resin may be 1,000 to 10,000, preferably 1,500 to 5,000 have.

The thickness of the film for forming a polarizer is not particularly limited, and may be, for example, 10 to 150 mu m.

Protective layer

The protective layer according to the present invention may be formed on at least one surface of the polarizer, and the protective layer may include at least one of, for example, a protective film and a hard coat layer.

According to an embodiment of the present invention, the protective layer may include a protective film.

The kind of the protective film is not particularly limited as long as it is excellent in transparency, mechanical strength, thermal stability, moisture barrier property, isotropy and the like. Specifically, an acrylic resin film such as polymethyl (meth) acrylate and polyethyl (meth) ; Polyester based resin films such as polyethylene terephthalate, polyethylene isophthalate, polyethylene naphthalate and polybutylene terephthalate; Cellulose-based resin films such as diacetylcellulose and triacetylcellulose; Polyolefin-based resin films such as polyethylene, polypropylene, cyclo-based or norbornene structures, polyolefin-based or ethylene-propylene copolymer; A polyarylate resin film; Polyethersulfone resin film, and the like, but the present invention is not limited thereto.

When a protective film is formed on both sides of the polarizer according to the present invention, the protective film on both sides may be the same substrate or may be a different substrate.

The thickness of the protective film is not particularly limited, but may be 10 to 200 占 퐉, preferably 10 to 150 占 퐉. When the polarizer protective film is laminated on both sides of the polarizer, the respective protective films may have the same or different thicknesses.

When the protective film is used as a polarizing plate, the protective film is bonded to one surface of the polarizer, and the surface to be bonded to the polarizer may be subjected to an easy bonding treatment for improving bonding strength. The bonding facilitating treatment is not particularly limited as long as the bonding strength between the polarizer and the protective film can be improved. For example, dry treatment such as primer treatment, plasma treatment and corona treatment; Chemical treatment such as alkali treatment (saponification treatment); Low-pressure UV treatment and the like.

According to another embodiment of the present invention, the protective layer may include a hard coating layer. The hard coating layer is intended to prevent damage to the surface of the polarizing plate, but is not limited thereto.

The hard coating layer according to the present invention includes both a hard coating layer alone or a film form having a hard coating layer.

The hard coat layer according to the present invention is generally used in the art and can be used without limitation as long as the composition does not deviate from the object of the present invention. Preferably, the composition includes a binder resin, a polymerizable monomer, a polymerization initiator and a solvent As shown in FIG.

When the composition for forming a hard coat layer according to the present invention has the above-described structure, the binder resin is generally used in the art and is not limited in its kind. Examples of the binder resin include polyethylene glycol di Acrylate, urethane acrylate or urethane methacrylate, a polyester resin, a polyether resin, an acrylic resin, an epoxy resin, a urethane resin, an alkyd resin, a spiroacetal resin, a polybutadiene resin, These can be used individually or in combination of two or more.

The weight average molecular weight of the binder resin is not particularly limited, but may be specifically 200 to 2000, preferably 200 to 600. [

The binder resin may be included in an amount of 10 to 30 parts by weight based on 100 parts by weight of the composition for forming a hard coat layer of the present invention.

When the composition for forming a hard coat layer according to the present invention has the above-described constitution, the polymerizable monomer is generally used in the art and is not limited to the type as long as it does not deviate from the object of the present invention. Specifically, And the like. The acrylic monomer is not particularly limited as long as it is generally used in the art, and specific examples thereof include ethyl (meth) acrylate, ethylhexyl (meth) acrylate, trimethylolpropane triacrylate, bisphenol A-ethylene glycol Diacrylate, and the like. These may be used individually or in combination of two or more.

The polymerizable monomer may be included in an amount of 5 to 30 parts by weight based on 100 parts by weight of the composition for forming a hard coat layer of the present invention.

When the composition for forming a hard coating layer according to the present invention has the above-described constitution, the polymerization initiator is used for sufficiently progressing the inside of the coating layer and the surface hardening, and is generally used in the art. There is no limitation on the type thereof as long as it can not escape, and a photopolymerization initiator and the like are preferable. These may be used individually or in combination of two or more.

The photopolymerization initiator is not particularly limited as long as it is generally used in the art. Specific examples thereof include 1-hydroxycyclohexyl phenyl ketone, diphenyl ketone rubidium dimethyl ketal, acetophenon dimethyl ketal, p-dimethylaminobenzoic acid Ester, and 2-hydroxy-2-methyl-1-phenyl-1- can be prepared by reacting 4-hydroxycyclophenyl ketone, dimethoxy-2-phenylacetophenone, anthraquinone, 2-aminoanthraquinone, Amine, carbazole, benzophenone, p-phenylbenzophenone, 3-methylacetophenone, 4,4-dimethoxyacetophenone, 4,4-diaminobenzophenone, benzoin and 2- These may be used alone or in combination of two or more.

The polymerization initiator may be included in an amount of 1 to 25 parts by weight based on 100 parts by weight of the composition for forming a hard coat layer of the present invention.

When the composition for forming a hard coating layer according to the present invention has the above-described constitution, the solvent is used for controlling the thickness of the hard coating layer and maintaining good coating property, and is generally used in the art, There are no limitations on the type of the solvent, and examples thereof include methanol, ethanol, isopropanol, propanol, butanol, isobutanol, ethyl cellosolve, methyl cellosolve, butyl acetate, dimethyl formamide, diacetone alcohol, Isopropyl alcohol, propylene glycol isopropyl alcohol, methyl ethyl ketone, N-methyl pyrrolidone, etc. These may be used alone or in combination of two or more.

The solvent may be included in an amount of 30 to 80 parts by weight based on 100 parts by weight of the composition for forming a hard coat layer of the present invention.

The hard coat layer composition according to the present invention may further comprise additives as required. The additive is generally used in the art and is not limited as long as it does not deviate from the object of the present invention. Specific examples thereof include antioxidants, ultraviolet absorbers, light stabilizers, leveling agents, lubricants and the like .

The hard coating layer according to the present invention is generally used in the art, and there is no particular limitation on the method of forming the hard coating layer as long as the hard coating layer does not deviate from the object of the present invention.

When the polarizer and the protective layer according to the present invention are laminated, an adhesive may be used if necessary.

The type of the adhesive is generally used in the art and is not particularly limited within the scope of the present invention. Specific examples thereof include an isocyanate adhesive, a polyvinyl alcohol adhesive, a gelatin adhesive, a vinyl polymer latex type Adhesives, and water-soluble polyester-based adhesives. Based adhesives, non-water-based adhesives, and non-water-based adhesives. However, water-based adhesives are more preferable, and specifically 0.5 to 60% by weight of solids may be contained.

The adhesive may be applied to at least one of the polarizer or the protective layer and is subjected to a drying treatment after bonding to form an adhesive layer comprising the applied dried layer. The bonding treatment of the polarizer and the protective layer can be performed using a roll laminator or the like. The thickness of the adhesive layer is not particularly limited, but may be specifically 0.1 to 5 mu m.

The polarizing plate of the present invention may optionally include an optical functional layer. The optical functional layer may be included in an image display device as a separate independent layer, and may be used as an optical functional film such as a retardation film, an antireflection film, an antistatic film, an antifouling film, or a fingerprint prevention film commonly used in the art It is possible.

Image display device

In addition, the present invention provides an image display device including the polarizing plate.

The polarizing plate according to the present invention can be applied to all ordinary image display devices and can constitute a liquid crystal display device including a liquid crystal panel in which a polarizing plate in which a pressure-sensitive adhesive layer is laminated is bonded to at least one surface of a liquid crystal cell .

A separate pressure-sensitive adhesive layer or an anchor layer may be interposed between the polarizing plate and the pressure-sensitive adhesive layer according to the present invention for the purpose of strengthening adhesion of the both.

The image display apparatus of the present invention may further include a configuration known in the art in addition to the polarizing plate.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to examples.

Example  One

Polarizer  Produce

A transparent unoriented polyvinyl alcohol film (VF-PS, KURARAY Co.) having a degree of saponification of 99.9% or more and a thickness of 75 μm was immersed in water (deionized water) at 30 ° C. and swelled. Then, 3.5 mmol / L of iodine and potassium iodide 2 Was immersed in an aqueous solution for dyeing at 30 DEG C containing 10% by weight and dyed.

Thereafter, the temperature of the crosslinking bath was set to 54 DEG C, and the resultant was immersed in a crosslinking aqueous solution containing 4.5 parts by mol of lithium chloride relative to 2 parts by weight of potassium iodide, 3.7 parts by weight of boric acid, and 1 part by weight of potassium iodide.

So that the total cumulative stretching ratio in the manufacturing process was 5.9 times, so that the thickness of the polyvinyl alcohol film was 23 占 퐉.

After completion of the crosslinking, the polyvinyl alcohol film was dried for 4 minutes in an oven at 70 DEG C under a load of 850 N / m to prepare a polarizer.

hard  Preparation of coating layer

2.8 parts by weight of trimethylolpropane triacrylate, 3.8 parts by weight of bisphenol A-ethylene glycol diacrylate, 13.4 parts by weight of polyethylene glycol diacrylate, 1 part by weight of isopropanol and 1 part by weight of methyl cellosolve, : 1, and 3 parts by weight of 1-hydroxycyclohexyl phenyl ketone were mixed to prepare a composition for forming a hard coat layer.

Then, by irradiating a directly applied on the thickness of the produced hard coat composition is 50㎛ transparent PET substrate film, and dried for one minute at 70 ℃ a total thickness such that the 20㎛ then, ultraviolet rays of 1J / cm ² curing To prepare a hard coat layer.

Production of Polarizer

The prepared hard coating layer was laminated on one surface of the polarizer and the TAC protective film (KINICA Co.) having a thickness of 60 μm on the other surface was laminated on both sides using an adhesive to prepare a polarizing plate. Using the acrylic pressure sensitive adhesive, Was attached to the liquid crystal panel and cured for 5 days.

Example  2

Except that a COP (cyclic olefin polymer) protective film (ZEON) having a thickness of 50 탆 was used in place of the TAC protective film, and a polarizing plate was produced in the same manner as in Example 1, And attached to a liquid crystal panel.

Example  3

A polarizing plate was produced in the same manner as in Example 1 except that a poly (methyl methacrylate) protective film (SUMITOMO Co., Ltd.) having a thickness of 80 占 퐉 was used in place of the TAC protective film, A polarizing plate was attached to the liquid crystal panel.

Example  4

A polarizing plate was produced in the same manner as in Example 1 except that a PMMA protective film (SUMITOMO Co., Ltd.) having a thickness of 60 탆 was used in place of the TAC protective film, and the polarizing plate was attached to the liquid crystal panel using an acrylic pressure-sensitive adhesive.

Example  5

A polarizing plate was prepared in the same manner as in Example 1 except that a PMMA protective film (SUMITOMO Co., Ltd.) having a thickness of 40 탆 was used in place of the TAC protective film, and the polarizing plate was attached to the liquid crystal panel using an acrylic pressure-sensitive adhesive.

Example  6

A polarizing plate was prepared in the same manner as in Example 1 except that a PMMA protective film (SUMITOMO Co., Ltd.) having a thickness of 80 mu m was laminated on both sides of the polarizer, and the polarizing plate was attached to the liquid crystal panel using an acrylic pressure-sensitive adhesive.

Example  7

A polarizing plate was prepared in the same manner as in Example 1 except that a PMMA protective film (SUMITOMO Co., Ltd.) having thicknesses of 60 탆 and 40 탆 on both sides of the polarizer was used, and the polarizing plate was attached to the liquid crystal panel using an acrylic pressure- Respectively.

Example  8

A polarizing plate was prepared in the same manner as in Example 1 except that a PMMA protective film (SUMITOMO Co., Ltd.) having thicknesses of 50 탆 and 30 탆 on both sides of the polarizer was used, and the polarizing plate was attached to the liquid crystal panel using an acrylic pressure- Respectively.

Example  9

A polarizing plate was produced in the same manner as in Example 1, except that a TAC protective film (KONICA) having a thickness of 60 μm on one surface of the polarizer and a protective film of 51 μm COP (Zeon Co.) were used on the other surface, The polarizer was attached to the liquid crystal panel using an adhesive.

Example  10

A polarizing plate was prepared in the same manner as in Example 1, except that a 40 占 퐉 -thick PET protective film (TOYOBO) was used on both sides of the polarizer, and the polarizing plate was attached to the liquid crystal panel using an acrylic pressure-sensitive adhesive.

Comparative Example  One

A polarizing plate was prepared in the same manner as in Example 1 except that a 30 占 퐉 -thick PMMA protective film was used in place of the TAC protective film, and the polarizing plate was attached to the liquid crystal panel using an acrylic pressure-sensitive adhesive.

Comparative Example  2

A polarizing plate was produced in the same manner as in Example 1 except that a 60 μm thick PET protective film (TOYOBO) was laminated on both sides of the prepared polarizer by double-side lamination using an adhesive and the curing time was changed to 10 days And the polarizer was attached to the liquid crystal panel using an acrylic pressure-sensitive adhesive.

Comparative Example  3

A polarizing plate was prepared in the same manner as in Example 7, except that the curing time was changed to 10 days.

Comparative Example  4

A PMMA protective film (SUMITOMO Co., Ltd.) having a thickness of 80 μm was laminated on one side of the polarizer, and a 51 μm COP (Zeon) protective film was laminated on the other side using an adhesive, and the curing time was changed to 7 days , A polarizing plate was produced in the same manner as in Example 1, and the polarizing plate was attached to the liquid crystal panel using an acrylic pressure-sensitive adhesive.

Comparative Example  5

A polarizing plate was produced in the same manner as in Example 1, except that the curing time was changed to 7 days.

Comparative Example  6

A polarizing plate was produced in the same manner as in Example 9, except that the composition for forming a pressure-sensitive adhesive was constructed as follows.

55 parts by weight of n-butyl acrylate (BA), 35 parts by weight of methyl acrylate (MA), 2 parts by weight of 2-hydroxyethyl acrylate ( 4 parts by weight of acrylic acid (AA-2-HEA), 0.1 part by weight of acrylic acid (AA) and 0.6 part by weight of butyl acrylate (BAA) were put into the flask and 100 parts by weight of ethyl acetate (EAc) was added as a solvent. The nitrogen gas was then purged for 1 hour and then maintained at 80 占 폚.

After the mixture was uniformly mixed, 0.07 part by weight of azobisisobutyronitrile (AIBN) was added as a polymerization initiator, and the mixture was reacted for 8 hours to prepare an acrylic copolymer (weight average molecular weight: about 1,000,000).

100 parts by weight of the acrylic copolymer prepared above, 3 parts of 1-hexyl-4-methylpyridinium hexafluorophosphate as an ionic antistatic agent, 0.6 part of Coronate L as a crosslinking agent and 0.5 part of a silane coupling agent KBM-403 were mixed, Ethyl acetate to prepare a pressure-sensitive adhesive composition having a concentration of 15% based on the solid content.

Experimental Example  One: TD  When a load is applied in the direction, In a polarizer Fracture  Measurement of the generated load

The polarizers prepared in the examples and comparative examples were manufactured with a width of 5 mm and a length of 100 mm, and the TD load at break was measured. The results are shown in Table 1 below.

Experimental Example  2: Measurement of adhesion

The polarizers prepared in Examples and Comparative Examples were produced with specimens having a width of 25 mm and a length of 100 mm, and the force at 180 ° peeling was measured. The results are shown in Table 1 below.

Experimental Example  3: Re-workability  evaluation

The liquid crystal panel with the polarizing plate was stored in an autoclave (50 DEG C, 0.5 MPa (about 5 atm)) for 20 minutes, placed in an oven at 50 DEG C for 4 hours, and then stored in a laboratory at 25 DEG C and 50% RH for 5 days. Thereafter, it was measured whether the adhesive remained on the liquid crystal panel while peeling off the stored sample at 90 DEG (peeling speed: 20 mm / sec).

FIG. 2 schematically shows the reworkability evaluation method, and the results are shown in Table 1 below.

<Evaluation Criteria>

?: When the protective layer does not peel off from the polarizing plate, and the adhesive does not remain on the panel and is peeled off cleanly

X: When the protective layer is peeled off from the polarizer and left on the panel

division The load X (N) at which the polarizer is broken,
0.06 * X + 2.4 Adhesive force (N / 25mm)
Re-workability size Curing time Example 1 43.0 4.98 4.2 5 days ○ Example 2 18.3 3.498 3.4 5 days ○ Example 3 22.5 3.75 3.7 5 days ○ Example 4 17.0 3.42 3.4 5 days ○ Example 5 16.8 3.408 3.4 5 days ○ Example 6 42.2 4.932 4.9 5 days ○ Example 7 30.9 4.254 4.2 5 days ○ Example 8 23.5 3.81 3.8 5 days ○ Example 9 60.5 6.03 6.0 5 days ○ Example 10 180 13.2 6.1 5 days ○ Comparative Example 1 12.5 3.15 3.9 5 days X Comparative Example 2 190 13.8 14 10 days X Comparative Example 3 30.9 4.254 6.5 10 days X Comparative Example 4 39.0 4.74 5.7 7 days X Comparative Example 5 43.0 4.98 5.2 7 days X Comparative Example 6 60.5 6.03 9.4 5 days X

Referring to Table 1, it can be confirmed that the embodiments falling within the scope of the present invention are superior to the comparative examples in reworkability.

Claims (7)

A polarizing plate comprising a polarizer and a protective layer formed on at least one surface of the polarizer and including an adhesive layer on the outer surface of the protective layer, characterized in that the polarizer has a first vertex portion fixed and a second vertex When a vertex portion is turned upside down and a load is applied in the TD direction,
Wherein a load (X) causing breakage in the polarizing plate and an adhesive force (Y) of the pressure-sensitive adhesive layer satisfy the following formula (1)
[Equation 1]
Y? 0.06X + 2.4
(Wherein X is 15 to 200 N).
The polarizing plate according to claim 1, wherein the polarizing plate has a load X of 15 to 150 N at which fracture occurs.
The polarizing plate according to claim 1, wherein the protective layer is a protective film.
The polarizer of claim 1, wherein the protective layer comprises a hard coat layer.
5. The polarizer of claim 4, wherein the hard coat layer is formed from a composition comprising a binder resin, a polymerizable monomer, a polymerization initiator, and a solvent.
[7] The composition according to claim 5, wherein the composition comprises 10 to 30 parts by weight of a binder resin, 5 to 30 parts by weight of a polymerizable monomer, 1 to 25 parts by weight of a polymerization initiator, and 30 to 80 parts by weight of a solvent, .
7. An image display device comprising the polarizing plate according to any one of claims 1 to 6.

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