KR20110109215A - Polarizing plate and liquid crystal display device comprising the same - Google Patents

Abstract

The present invention relates to a polarizing plate and a liquid crystal display device having the same, and more particularly, an auxiliary adhesive layer formed on a hydrophobic protective film and made of a hard coating resin is bonded to at least one surface of the polarizer via a water-based adhesive layer, thereby providing a polarizer. The present invention relates to a polarizing plate capable of securing sufficient durability under high temperature and high humidity by improving adhesion between the hydrophobic protective film and the hydrophobic protective film and a liquid crystal display device having the same.

Description

POLARIZING PLATE AND LIQUID CRYSTAL DISPLAY DEVICE COMPRISING THE SAME}

The present invention relates to a polarizing plate having excellent durability under a high temperature or a high temperature and high humidity environment due to improved adhesion between the polarizer and the hydrophobic protective film, and a liquid crystal display device having the same.

In general, a liquid crystal display device (LCD) includes a polarizing plate incorporated on both sides of a liquid crystal cell composed of a glass substrate or a plastic plate-like material including a liquid crystal layer and a transparent electrode layer.

The polarizing plate includes a polarizer protective film represented by a triacetyl cellulose film laminated to protect both surfaces of the iodine-based polarizer and the polarizer.

The polarizing plate configured as described above does not have sufficient heat and moisture resistance of a hydrophilic protective film such as a cellulose-based protective film, and thus, polarization performance such as polarization degree, color, etc. is easily deteriorated under high temperature or high temperature / humidity conditions. There is a disadvantage that it is easy to peel off.

In consideration of this point, the use of a hydrophobic protective film excellent in heat resistance and optical transparency as a polarizer protective film, for example, a protective film such as a polyolefin film, a polyester film or an acrylic film, has been proposed.

However, when the hydrophobic protective film is bonded to the polarizer by using the water-based adhesive, the adhesive force is not sufficient, and thus the adhesion between the polarizer and the protective film is not good, and thus the durability of the polarizing plate is greatly reduced under high temperature or high temperature and high humidity.

In order to solve this problem, Korean Laid-Open Patent No. 2008-7003863, Japanese Laid-Open Patent No. 2001-374810, and Japanese Laid-Open Patent No. 2001-334439 include an adhesive layer made of a hydrophilic cellulose resin, a polyester resin or a polyurethane resin. The method of improving the adhesive force with a polarizer using the formed polyester type film is disclosed. Although the adhesiveness was improved to some extent by this method, sufficient durability under high temperature or high temperature / humidity environment was not secured.

The present invention is to provide a polarizing plate that can improve the adhesion between the polarizer and the transparent protective film, in particular hydrophobic protective film to ensure excellent adhesion and sufficient durability under high temperature and high humidity environment.

In addition, the present invention is to provide a liquid crystal display device provided with the polarizing plate.

1. A polarizing plate, wherein the auxiliary adhesive layer formed on the hydrophobic protective film is bonded to at least one side of the polarizer via an aqueous adhesive layer, and the auxiliary adhesive layer is made of a hard coating resin.

2. In the above 1, the hydrophobic protective film is a polarizing plate which is a polyester film, an acrylic film or a polyolefin film.

3. In the above 1, the hard coat resin is a polymer of at least one UV curable monomer.

4. In the above 3, the ultraviolet curable monomer is a polarizing plate selected from the group consisting of acrylic monomers having 1 to 6 functional groups.

5. In the above 3 or 4, the ultraviolet curing acrylic monomer is methyl (meth) acrylate, allyl methacrylate, 2-ethoxyethyl (meth) acrylate, isodecyl (meth) acrylate, 2-dodecylthio Ethyl methacrylate, octyl acrylate, 2-methoxyethyl acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, isooctyl (meth) acrylic Monofunctional monomers which are late, isodecyl (meth) acrylate, stearyl (meth) acrylate, tetraperfuryl (meth) acrylate, phenoxyethyl (meth) acrylate and urethane acrylate; 1,3-butanedioldi (meth) acrylate, 1,4-butanedioldi (meth) acrylate, 1,6-hexanedioldi (meth) acrylate, ethylene glycoldi (meth) acrylate, bisphenol A-ethylene Glycol diacrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) Acrylate, neopentyl glycol di (meth) acrylate, dicyclopentanyldi (meth) acrylate, caprolactone modified dicyclopentenyldi (meth) acrylate, ethylene oxide modified phosphate di (meth) acrylate, bis (2 -Hydroxyethyl) isocyanurate di (meth) acrylate, di (acryloxyethyl) isocyanurate, allylated cyclohexyldi (meth) acrylate, dimethyloldicyclopentanediacrylate , Ethylene oxide-modified hexahydrophthalic acid diacrylate, tricyclodecane dimethanol diacrylate, neopentyl glycol-modified trimethylolpropane diacrylate, adamantyl tandi the acrylate difunctional monomer; Trimethylolpropane tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide modified trimethylolpropane Trifunctional monomers which are tri (meth) acrylate, tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate, tris (acryloxyethyl) isocyanurate, and glycerol tri (meth) acrylate; Tetrafunctional monomers which are diglycerin tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, and ditrimethylolpropane tetra (meth) acrylate; 5-functional monomers which are propionic acid-modified dipentaerythritol penta (meth) acrylates; And a six-functional monomer which is caprolactone-modified dipentaerythritol hexa (meth) acrylate.

6. In the above 1, the thickness of the auxiliary adhesive layer is 0.1 to 1.5㎛ polarizing plate.

7. In the above 1, the adhesive layer or a functional surface treatment layer laminated on the hydrophobic protective film polarizing plate.

8. In the above 1, the polyester-based film, cellulose film, polycarbonate film, acrylic film, styrene-based film, polyolefin-based film, vinyl chloride-based film, amide-based on the other side of the polarizer not bonded to the auxiliary adhesive layer Film, imide film, polyether sulfone film, sulfone film, polyethyl ketone film, polyphenylene sulfide film, vinyl alcohol film, vinylidene chloride film, vinyl butyral film, allylate film, poly A polarizing plate laminated with a transparent protective film selected from the group consisting of an oxymethylene-based film and an epoxy-based film.

9. The liquid crystal display of the upper polarizing plate 1 is provided with an upper polarizing plate, a lower polarizing plate, or an upper plate and a lower polarizing plate.

The polarizing plate according to the present invention has improved adhesion between the polarizer and the transparent protective film, in particular, the hydrophobic transparent protective film, thereby improving adhesion and ensuring sufficient durability in a high temperature and high humidity environment.

1 is a cross-sectional view of a polarizing plate according to an embodiment of the present invention,
2 is a cross-sectional view of a polarizer according to another embodiment of the present invention.

The present invention relates to a polarizing plate having excellent durability under a high temperature or a high temperature and high humidity environment due to improved adhesion between the polarizer and the hydrophobic protective film, and a liquid crystal display device having the same.

Hereinafter, the present invention will be described in detail.

The polarizing plate of the present invention is characterized in that the auxiliary adhesive layer formed on the hydrophobic protective film is bonded to at least one surface of the polarizer via a water-based adhesive layer, the auxiliary adhesive layer is made of a hard coating resin.

In the polarizing plate according to the exemplary embodiment of the present invention, as shown in FIG. 1, a hydrophobic protective film is bonded to one surface of the polarizer, and then, in the order of a transparent protective film / adhesive layer / polarizer / adhesive layer / auxiliary adhesive layer / hydrophobic protective film. It is a laminated structure (FIG. 1A). In addition, the hydrophobic protective film is bonded to both sides of the polarizer is a laminated structure in the order of the hydrophobic protective film / auxiliary adhesive layer / adhesive layer / polarizer / adhesive layer / auxiliary adhesive layer / hydrophobic protective film (Fig. 1b).

A polarizer is a dichroic dye adsorbed and oriented on a polyvinyl alcohol-based film.

The polyvinyl alcohol-based resin constituting the polarizer can be obtained by saponifying a polyvinyl acetate-based resin. As polyvinyl acetate type resin, the copolymer etc. of vinyl acetate and the other monomer copolymerizable with this besides the polyvinyl acetate which is a homopolymer of vinyl acetate are mentioned. As another monomer copolymerizable with vinyl acetate, an unsaturated carboxylic acid type, an unsaturated sulfonic acid type, an olefin type, a vinyl ether type, an acrylamide type monomer which has an ammonium group, etc. are mentioned. The polyvinyl alcohol resin may be modified, for example, polyvinyl formal, polyvinyl acetal, or the like modified with aldehydes may also be used. The saponification degree of the polyvinyl alcohol-based resin is usually 85 to 100 mol%, preferably 98 mol% or more, and the polymerization degree is usually 1,000 to 10,000, preferably 1,500 to 5,000.

What formed such a polyvinyl alcohol-type resin into a film is used as a raw film of a polarizer. The film formation method of polyvinyl alcohol-type resin is not specifically limited, A well-known method can be used. The film thickness of the polyvinyl alcohol based film is not particularly limited, and may be, for example, 10 to 150 μm.

A polarizer is usually manufactured through the process of uniaxial stretching of the above-mentioned polyvinyl alcohol-type film, the process of dyeing and adsorbing with a dichroic substance, the process of treating with boric acid aqueous solution, the process of washing with water, and drying.

The hydrophobic protective film is a film for protecting the polarizer and at the same time as a base film for forming the auxiliary adhesive layer, it is possible to use a film excellent in transparency, mechanical strength, thermal stability, moisture shielding, isotropy. Specifically, polyester-based resin, such as polyethylene terephthalate, polyethylene isophthalate, polybutylene terephthalate; Acrylic resins such as polymethyl (meth) acrylate and polyethyl (meth) acrylate; And films composed of thermoplastic resins such as polyethylene, polypropylene, polyolefin resins having a cyclo or norbornene structure, polyolefin resins such as ethylene propylene copolymers, and the like, and films composed of blends of the above thermoplastic resins may also be used. . The hydrophobic protective film may be unstretched, uniaxially or biaxially stretched.

The thickness of the hydrophobic protective film is usually 1 to 500㎛, preferably 1 to 300㎛, more preferably 20 to 100㎛.

In the present invention, the auxiliary adhesive layer is a layer that facilitates the adhesion between them in bonding the polarizer and the hydrophobic protective film with an aqueous adhesive, in particular, characterized in that made of a hard coating resin.

The hard coat resin is a photopolymer of at least one ultraviolet curable monomer, and may be prepared from a hard coat liquid composition used to form a hard coat layer for protecting a surface of a polarizing plate.

The hard coating liquid composition may include an ultraviolet curable acrylic monomer having 1 to 6 functional groups, a photopolymerization initiator, and an organic solvent.

Specific examples of the ultraviolet curing acrylic monomers include methyl (meth) acrylate, allyl methacrylate, 2-ethoxyethyl (meth) acrylate, isodecyl (meth) acrylate, 2-dodecylthioethyl methacrylate, Octyl acrylate, 2-methoxyethyl acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, isooctyl (meth) acrylate, isodecyl ( Monofunctional monomers such as meth) acrylate, stearyl (meth) acrylate, tetraperfuryl (meth) acrylate, phenoxyethyl (meth) acrylate and urethane acrylate; 1,3-butanedioldi (meth) acrylate, 1,4-butanedioldi (meth) acrylate, 1,6-hexanedioldi (meth) acrylate, ethylene glycoldi (meth) acrylate, bisphenol A-ethylene Glycol diacrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) Acrylate, neopentyl glycol di (meth) acrylate, dicyclopentanyldi (meth) acrylate, caprolactone modified dicyclopentenyldi (meth) acrylate, ethylene oxide modified phosphate di (meth) acrylate, bis (2 -Hydroxyethyl) isocyanurate di (meth) acrylate, di (acryloxyethyl) isocyanurate, allylated cyclohexyldi (meth) acrylate, dimethyloldicyclopentanediacrylate , Ethylene oxide-modified hexahydrophthalic acid diacrylate, tricyclodecane dimethanol diacrylate, neopentyl glycol-modified trimethylolpropane diacrylate, adamantyl bifunctional monomers such as tandi acrylate; Trimethylolpropane tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide modified trimethylolpropane Trifunctional monomers such as tri (meth) acrylate, tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate, tris (acryloxyethyl) isocyanurate, and glycerol tri (meth) acrylate ; Tetrafunctional monomers such as diglycerin tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate; Pentafunctional monomers such as propionic acid-modified dipentaerythritol penta (meth) acrylate; And six-functional monomers such as caprolactone-modified dipentaerythritol hexa (meth) acrylate, and the like, and among these, 1-3 functional monomers are preferable. These can be used individually or in mixture of 2 or more types.

UV-curable acrylic monomer may be included in 10 to 60% by weight based on 100% by weight of the hard coating liquid composition. If the content is less than 10% by weight, the hardness of the auxiliary adhesive layer is weakened. If the content is more than 60% by weight, the hardness of the auxiliary adhesive layer is too high, resulting in poor handleability.

The photopolymerization initiator is for sufficiently proceeding the internal and surface curing of the coating layer, and specific examples thereof include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, and benzoin isobutyl Ether, acetophenone, dimethylaminoacetophenone, dimethoxy-2-phenylacetophenone, 3-methylacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone , 4-Chronolocetophenone, 4,4-dimethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 4-hydroxycyclophenyl ketone, 1-hydroxycyclohexylphenyl Ketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propane-1-one, 4- (2-hydroxyethoxy) phenyl-2- (hydroxy-2- Propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4-diaminobenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, anthraquinone, 2-methylanthraquinone, 2-ethyl Traquinone, 2-t-butyl anthraquinone, 2-aminoanthraquinone, 2-methyl thioxanthone, 2-ethyl thioxanthone, 2-chlorothioxanthone, 2,4-dimethyl thioxanthone, 2,4 Diethyl thioxanthone, benzyl dimethyl ketal, diphenyl ketone benzyl dimethyl ketal, acetophenone dimethyl ketal, p-dimethylaminobenzoic acid ester, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, fluorene, tri Phenylamine, carbazole, etc. are mentioned, These can be used individually or in combination of 2 or more types.

The photopolymerization initiator may be included in an amount of 0.1 to 10 wt% based on 100 wt% of the hard coating solution composition. If the content is less than 0.1% by weight, the curing speed is slow, and if the content is more than 10% by weight, cracks may occur in the auxiliary adhesive layer.

The organic solvent is used to maintain the thickness control of the auxiliary adhesive layer and good coating properties, and any organic solvent having no problem in compatibility with an ultraviolet curing acrylic monomer may be used. Specific examples include methanol, ethanol, isopropanol, propanol, butanol, isobutanol, ethyl cellosolve, methyl cellosolve, ethyl acetate, butyl acetate, dimethylformamide, diacetone alcohol, ethylene glycol isopropyl alcohol, propylene glycol iso Propyl alcohol, methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, diethyl ketone, dipropyl ketone, N-methylpyrrolidone, toluene, and the like. These may be used alone or in combination of two or more thereof.

The organic solvent may be included in 30 to 80% by weight based on 100% by weight of the hard coating liquid composition. If the content is less than 30% by weight, there is a problem in coating property, it is difficult to form a uniform auxiliary adhesive layer, when the content is more than 80% by weight may be too thin thickness of the adhesion aid.

The hard coating resin including the above components may further include additives such as reactive silica particles, antioxidants, ultraviolet absorbers, light stabilizers, leveling agents, surfactants, lubricants, antistatic agents and the like as necessary.

The auxiliary adhesive layer may be formed by applying a hard coating solution composition on the hydrophobic protective film. The coating method is not particularly limited and may be a method known in the art, for example, a bar coater, air knife, gravure, reverse roll, kiss roll, spray, blade, die coater, casting, spin coating, or the like. . Specifically, after applying the hard coating liquid composition on the hydrophobic protective film, and dried for 1 second to 2 hours, preferably 5 seconds to 1 hour at 30 to 150 ℃ about 0.01 to 10J / ㎠, preferably 0.1 to 2J It can be completely cured by irradiating with an ultraviolet irradiation amount of / cm 2 to form an auxiliary adhesive layer made of a photopolymerized hard coating resin.

It is preferable that the thickness of an auxiliary adhesive layer after drying is 0.1-1.5 micrometers, More preferably, it is 0.5-1 micrometer. If the thickness is less than 0.1㎛ adhesion assistant effect for the bonding of the hydrophobic protective film may be insignificant, if it exceeds 1.5㎛ thicker than the adhesive layer can increase the production cost.

The auxiliary adhesive layer may be laminated on one or both sides of the polarizer.

The auxiliary adhesive layer formed as described above is laminated between the polarizer and the hydrophobic protective film through a water-based adhesive layer, thereby serving as an adhesion assistant of the water-based adhesive layer. In particular, the reason why the layer made of a hard coating resin shows an effect as an auxiliary adhesive layer is not clear, but the additional configuration of the auxiliary adhesive layer improves the adhesion between the polarizer and the hydrophobic protective film, so that the polarizing plate has excellent durability even at high temperature and high humidity. To ensure that

The polarizer and the auxiliary adhesive layer are laminated by bonding through the aqueous adhesive layer.

The water-based adhesive layer is composed of a single or a mixture of two or more kinds of water-based adhesives such as isocyanate-based, polyvinyl alcohol-based, gelatin-based, vinyl polymer-based latex-type, and water-soluble polyester, and the water-based adhesives are water-soluble adhesives. It may be 0.5 to 60% by weight.

The bonding method may use a conventional method in the art, for example, by applying a water-based adhesive to at least one side of the bonding surface of the polarizer or the adhesive auxiliary layer, the method of coating, meyer bar coating, gravure coating, die coating, dip coating, spray After coating in a suitable development method using a coating method such as coating, these can be superimposed, dried and laminated. At this time, a roll laminator can be used.

A conventional transparent protective film may be laminated on the other side of the polarizer not bonded to the auxiliary adhesive layer. Specifically, polyester-based resin, such as polyethylene terephthalate, polyethylene isophthalate, polybutylene terephthalate; Cellulose resins such as diacetyl cellulose and triacetyl cellulose; Polycarbonate resin; Acrylic resins such as polymethyl (meth) acrylate and polyethyl (meth) acrylate; Styrene resins such as polystyrene and acrylonitrile-styrene copolymers; Polyolefin resins such as polyethylene, polypropylene, cyclo- or polyolefin resins having a norbornene structure, and ethylene propylene copolymers; Vinyl chloride-based resins; Polyamide resins such as nylon and aromatic polyamide; Imide resin; Polyether sulfone resin; Sulfone resins; Polyether ketone resins: sulfide polyphenylene resins; Vinyl alcohol-based resins; Vinylidene chloride-based resins; Vinyl butyral resin; Allyl resins; Polyoxymethylene resin; And films composed of thermoplastic resins such as epoxy resins, and the like, and films composed of blends of the above thermoplastic resins may also be used. Moreover, you may use the film which consists of thermosetting resins or ultraviolet curable resins, such as (meth) acrylic-type, urethane type, epoxy type, and silicone type.

The hydrophobic protective film and the transparent protective film may be films having an optical compensation function.

In addition, the same water-based adhesive and bonding method as described above are used in the lamination of the polarizer and the transparent protective film.

In the polarizing plate according to another embodiment of the present invention, as illustrated in FIG. 2, an adhesive layer or a functional surface treatment layer may be stacked on a hydrophobic protective film. Specifically, a structure in which an adhesive layer for bonding to a liquid crystal cell is laminated on a hydrophobic protective film laminated with an auxiliary adhesive layer (FIG. 2A), and a structure in which an adhesive layer is laminated on another transparent protective film not laminated with the auxiliary adhesive layer ( FIG. 2B) may be a structure in which a functional surface treatment layer is laminated in place of the pressure-sensitive adhesive layer (not shown). In addition, the functional surface treatment layer is laminated on one of the protective film of the hydrophobic protective film or the transparent protective film, the pressure-sensitive adhesive layer may be laminated on the other protective film (Fig. 2c-e).

An adhesive layer is a layer formed from the adhesive composition containing an adhesive resin, a crosslinking agent, and a silane coupling agent as needed, The adhesive resin can use what has an acryl-type or urethane type resin as a main component, and acrylic resin is good transparency among these, desirable.

The functional surface treatment layer may be a layer having functions such as antireflection, low reflection, non-reflection, anti-glare, low refractive index, high refractive index, electromagnetic shielding, anti-glare or antistatic.

The liquid crystal display device of the present invention is characterized by comprising the polarizing plate. In more detail, the liquid crystal display device including the liquid crystal panel which bonded the polarizing plate in which the adhesive layer was laminated | stacked on at least one surface of the liquid crystal cell can be comprised.

The liquid crystal display device may include the polarizing plate of the present invention in an upper polarizing plate, a lower polarizing plate, or both.

In the present invention, since the liquid crystal display is well known in the art, detailed descriptions of the respective structures are omitted.

Hereinafter, preferred examples are provided to aid the understanding of the present invention, but the following examples are merely for exemplifying the present invention, and it will be apparent to those skilled in the art that various changes and modifications can be made within the scope and spirit of the present invention. It is natural that such variations and modifications fall within the scope of the appended claims.

EXAMPLE

Example 1

(1) auxiliary adhesive 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, 64 parts by weight of an organic solvent in which isopropanol and methyl cellosolve are mixed in a weight ratio of 1: 1. 3 parts by weight of 1-hydroxycyclohexylphenyl ketone was mixed, and a small amount of propylene wax and an ultraviolet absorbent as a light stabilizer were added thereto to prepare a hard coating solution composition.

The prepared hard coating solution composition was dried on a hydrophobic polymethyl methacrylate (PMMA) protective film having a thickness of 80 μm, and then directly applied to have a thickness of 1 μm, and dried at 70 ° C. for 1 minute. Subsequently, it was irradiated with an ultraviolet irradiation amount of 1 J / cm 2 to completely cure to form an auxiliary adhesive layer made of a hard coating resin.

(2) polarizer

A polyvinyl alcohol-based (PVA) polarizer was manufactured by bonding the formed auxiliary adhesive layer to both surfaces of the polarizer using a polyvinyl alcohol-based adhesive.

(3) polarizing plate with pressure-sensitive adhesive

A conventional acrylic pressure-sensitive adhesive was applied on a film coated with a silicone release agent to have a dry film thickness of 25 μm, and dried at 100 ° C. for 1 minute to form an adhesive layer. An adhesive sheet was prepared by laminating another release film thereon. The release film of the pressure-sensitive adhesive sheet was peeled off, and the pressure-sensitive adhesive layer was laminated on the hydrophobic protective film of the prepared polarizing plate.

Example 2

In the same manner as in Example 1, a polyethylene terephthalate (PET) film was used as a hydrophobic protective film for forming an auxiliary adhesive layer.

Comparative Example 1

In the same manner as in Example 1, except that the auxiliary adhesive layer is not formed on both sides of the polarizer was bonded through a polyvinyl alcohol adhesive.

Comparative Example 2

In the same manner as in Example 1, a polyurethane-based resin was used in place of the hard coating resin when forming the auxiliary adhesive layer.

Comparative Example 3

In the same manner as in Example 1, in the formation of the auxiliary adhesive layer was used instead of the hard coating resin water-based acrylic resin.

Comparative Example 4

In the same manner as in Example 1, the PET film is not bonded to both sides of the polarizer through the polyvinyl alcohol adhesive.

Comparative Example 5

In the same manner as in Example 1, a PET film was used in place of the PMMA film, and a polyurethane-based resin was used in place of the hard coating resin when the auxiliary adhesive layer was formed.

Test Example

The physical properties of the polarizing plates prepared in Examples and Comparative Examples were measured by the following method, and the results are shown in Table 1 below.

1. Adhesion

(1) cutter evaluation

The prepared polarizing plate was left at room temperature for 1 hour, a scratch was made between the polarizer and the hydrophobic protective film using a cutter blade, and the degree of peeling at the interface between the hydrophobic protective film and the polarizer was observed and evaluated based on the following criteria. .

(Circle): There is no peeling in an interface.

(Triangle | delta): Peeling in an interface is 5 mm or less.

X: Peeling at an interface exceeds 10 mm (processing with NG).

(2) folding evaluation

Using a cutter blade on the hydrophobic protective film of the prepared polarizing plate to make a scratch of 10mm size, folded the polarizing plate around the portion and observed the mixing of bubbles in the folded portion, and evaluated based on the following criteria.

(Circle): It cuts without bubble mixing.

(Triangle | delta): 1-10 mm generation | occurrence | production of bubble mixing (determination of whether product application is possible is necessary).

X: The mixing of bubbles exceeded 10 mm (treated with NG).

2. Wet Resistance

The prepared polarizing plate was cut into a size of 20 mm × 50 mm and eroded in warm water at 60 ° C. for 30 minutes, and then the shrinkage length and color fading of the polarizer were measured, and the total amount of erosion, which is the sum of the measured shrinkage length and color fading, was measured. Calculated in relative figures.

3. Durable

The prepared pressure-sensitive adhesive polarizing plate was cut to a size of 100 mm × 100 mm, the release film was peeled off, and then attached to a glass substrate to prepare a specimen. The prepared specimens were treated at 50 ° C. and 5 atmospheres in an autoclave for 20 minutes and then subjected to durability evaluation. At this time, the heat resistance at 80 ℃, the heat and humidity resistance at 60 ℃ and 90% RH, the cold resistance at -40 ℃ for about 750 hours after treatment for delamination and bubbles between the hydrophobic protective film and the polarizer were observed, and the following criteria It evaluated based on.

○: no delamination or bubbles (OK)

△: peeling phenomenon and bubbles are somewhat present (NG)

X: exfoliation and many bubble generation (NG)

division Transparency
Protective film Auxiliary adhesive layer
Suzy Adhesion Wet Resistance durability cutter
evaluation Folded
evaluation Heat resistant
(80 ℃) Heat resistance
(60 ℃, 90% RH) Cold
(-40 ℃) Example 1 PMMA Hard coating ○ ○ 0.7 ○ ○ ○ Example 2 PET Hard coating ○ ○ 0.9 ○ ○ ○ Comparative Example 1 PMMA - × × Not rated - - - Comparative Example 2 PMMA PU × △ 2.5 × × ○ Comparative Example 3 PMMA Dispersion AC × △ 2.3 × × ○ Comparative Example 4 PET - × × Not rated - - - Comparative Example 5 PET PU × ○ 1.7 × × ○

As shown in the above table, the polarizing plates of Examples 1 and 2 bonded through the auxiliary adhesive layer made of a hard coating resin formed on the hydrophobic protective film and the water-based adhesive according to the present invention have the adhesive strength between the polarizers even though the polarizing plates include the hydrophobic protective film. As a result, it was confirmed that not only the adhesiveness and the wettability but also the heat, moisture and heat resistance were excellent.

Claims (9)

The auxiliary adhesive layer formed on the hydrophobic protective film is bonded to at least one side of the polarizer via a water-based adhesive layer, the auxiliary adhesive layer is a polarizing plate made of a hard coating resin.
The polarizing plate according to claim 1, wherein the hydrophobic protective film is a polyester film, an acrylic film, or a polyolefin film.
The polarizing plate of claim 1, wherein the hard coating resin is a polymer of at least one ultraviolet curable monomer.
The polarizing plate according to claim 3, wherein the ultraviolet curable monomer is selected from the group consisting of 1 to 6 functional acrylic monomers.
The ultraviolet curable acrylic monomer according to claim 3 or 4, wherein the acrylic monomer is methyl (meth) acrylate, allyl methacrylate, 2-ethoxyethyl (meth) acrylate, isodecyl (meth) acrylate, 2-dodecylthioethyl meth. Acrylate, octyl acrylate, 2-methoxyethyl acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, isooctyl (meth) acrylate, Monofunctional monomers which are isodecyl (meth) acrylate, stearyl (meth) acrylate, tetraperfuryl (meth) acrylate, phenoxyethyl (meth) acrylate, and urethane acrylate; 1,3-butanedioldi (meth) acrylate, 1,4-butanedioldi (meth) acrylate, 1,6-hexanedioldi (meth) acrylate, ethylene glycoldi (meth) acrylate, bisphenol A-ethylene Glycol diacrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) Acrylate, neopentyl glycol di (meth) acrylate, dicyclopentanyldi (meth) acrylate, caprolactone modified dicyclopentenyldi (meth) acrylate, ethylene oxide modified phosphate di (meth) acrylate, bis (2 -Hydroxyethyl) isocyanurate di (meth) acrylate, di (acryloxyethyl) isocyanurate, allylated cyclohexyldi (meth) acrylate, dimethyloldicyclopentanediacrylate , Ethylene oxide-modified hexahydrophthalic acid diacrylate, tricyclodecane dimethanol diacrylate, neopentyl glycol-modified trimethylolpropane diacrylate, adamantyl tandi the acrylate difunctional monomer; Trimethylolpropane tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide modified trimethylolpropane Trifunctional monomers which are tri (meth) acrylate, tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate, tris (acryloxyethyl) isocyanurate, and glycerol tri (meth) acrylate; Tetrafunctional monomers which are diglycerin tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, and ditrimethylolpropane tetra (meth) acrylate; 5-functional monomers which are propionic acid-modified dipentaerythritol penta (meth) acrylates; And a six-functional monomer which is caprolactone-modified dipentaerythritol hexa (meth) acrylate.
The polarizing plate of claim 1, wherein the thickness of the auxiliary adhesive layer is 0.1 to 1.5 μm.
The polarizing plate according to claim 1, wherein an adhesive layer or a functional surface treatment layer is laminated on a hydrophobic protective film.
The film of claim 1, wherein the polyester film, the cellulose film, the polycarbonate film, the acrylic film, the styrene film, the polyolefin film, the vinyl chloride film, the amide film, Imide film, polyether sulfone film, sulfone film, polyethyl ketone film, polyphenylene sulfide film, vinyl alcohol film, vinylidene chloride film, vinyl butyral film, allylate film, polyoxymethylene Polarizing plate laminated with a transparent protective film selected from the group consisting of a film and an epoxy film.
The liquid crystal display device of claim 1, wherein the polarizer is provided as an upper polarizer, a lower polarizer, or an upper and lower polarizer.

Images