KR101783210B1 - Composite polarizing plate and display device comprising the same - Google Patents

Abstract

The present invention relates to a composite polarizing plate, and more particularly, to a polarizing plate. And a compound retardation layer disposed on at least one side of the polarizer, wherein the compound retardation layer is laminated from the polarizer in the order of a first retardation layer, a light curable adhesive layer, and a second retardation layer, The slope of the stiffness with respect to the temperature is -514 to -275, the bending characteristics of the display and the adhesion characteristics between the retardation layers are improved, the stiffness of the compound phase difference layer is improved, the warp characteristic is improved, have.

Description

Technical Field [0001] The present invention relates to a composite polarizer and an image display device including the composite polarizer.

The present invention relates to a composite polarizing plate and an image display apparatus including the same.

The development trend of information display is aimed at mobility and convenience in accordance with the mobility of information display terminal such as mobile phone and PDA at the center of high performance and high function that realizes objects in a realistic manner, A demand for a flexible display having a lightweight and easily foldable characteristic is rapidly increasing.

Specifically, a flexible display is a display manufactured using a thin and flexible substrate that can be bent or bent, and can be distinguished as a rugged display, a bendable display, or a rollable display depending on purposes and functions. A thin film transistor (TFT) element substrate, a color filter substrate, a touch screen panel substrate, and a solar cell substrate for a liquid crystal display device (LCD) or an organic EL display device (OLED) , Which is being developed to replace the heavy and fragile plate glass used in conventional flat panel displays (FPDs) with thin and flexible substrates to secure various applications from space and shape restrictions, ultimately, Continuous R & D is being conducted with the aim of commercializing paper-like displays.

The flexible substrate used in such a flexible display has a multi-layer structure. In order to bond the retardation layers included in the multi-layer structure, an adhesive is used. On the other hand, flexible substrates are often bent when used, and when the bonding force between the retardation layers is weak, the adhesive layer expands or peeling occurs between the retardation layers.

Korean Patent No. 1191865 discloses a technique relating to a flexible substrate.

Korean Patent No. 1191865

It is an object of the present invention to provide a composite polarizer in which the bending property of the display and the adhesion property between the retardation layers are improved.

Another object of the present invention is to provide a composite polarizer which exhibits improved stiffness and improved warping characteristics of the composite retardation layer to exhibit good light leakage characteristics.

Further, the present invention can provide an image display device including the composite polarizing plate as described above.

1. polarizer; And a compound retardation layer disposed on at least one side of the polarizer, wherein the compound retardation layer is laminated from the polarizer in the order of a first retardation layer, a light curable adhesive layer, and a second retardation layer, Wherein the slope of the stiffness with respect to the temperature is -514 to -275.

2. The composite polarizer of claim 1, wherein the first retardation layer is a? / 2 retardation layer and the second retardation layer is a? / 4 retardation layer.

3. The composite polarizer of claim 1, wherein the photocurable adhesive comprises an alicyclic epoxy compound and a linear aliphatic epoxy compound.

4. The composite polarizer of claim 3, wherein the weight ratio of the alicyclic epoxy compound to the linear aliphatic epoxy compound is 1: 1.5 to 4.

5. The composite polarizer of claim 3, wherein the alicyclic epoxy compound is 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate.

6. The composition of claim 3, wherein the linear aliphatic epoxy compound is selected from the group consisting of neopentyl glycol diglycidyl ether, 1,2,7,8-Diepoxyoctane ), 1,4-butanediol diglycidyl ether, 2-ethyl hexyl glycidyl ether, 1,2-epoxy-9-decene (1 (2-Epoxy-9-decene) and 2,3-epoxy-1- (1-ethoxyethoxy) Phosphorus, and complex polarizers.

7. The composite polarizing plate according to item 1 above, wherein the coating thickness of the photocurable adhesive layer is 0.01 to 5 占 퐉.

8. The composite polarizing plate as in 1 above, wherein the thickness of the composite retardation layer is 2 to 7 占 퐉.

9. The composite polarizer of claim 1, wherein the polarizer comprises a polarizing film, or a polarizing coating on a substrate film and a substrate film.

10. The composite polarizer of claim 1, wherein the composite retardation layer is disposed on one side of the polarizer and the protective film is bonded on the other side.

11. An image display device comprising any one of the composite polarizers of any one of (1) to (10).

In the composite polarizing plate of the present invention, the bending properties of the display and the adhesion characteristics between the retardation layers can be improved.

In addition, the composite polarizing plate of the present invention can exhibit good light leakage characteristics because the expansion ratio is reduced due to the improvement of the stiffness of the composite retardation layer and the warping property is improved.

In addition, since the composite polarizing plate of the present invention does not require a separate film peeling process in the manufacturing process, it is possible to reduce the defective rate.

Further, the present invention can provide an image display device including the composite polarizing plate as described above.

1 is a graph showing stiffness gradient according to an embodiment of the present invention and a comparative example.
2 is a schematic cross-sectional view of a composite polarizing plate according to an embodiment of the present invention.

One embodiment of the present invention relates to a polarizer comprising: a polarizer; And a compound retardation layer disposed on at least one side of the polarizer and laminated from the polarizer in order of a first retardation layer, a light curable adhesive layer, and a second retardation layer, wherein the compound retardation film has a refractive index in a range of 20 to 90 占 폚 The slope of the stiffness with respect to the temperature is -514 to -275, the bending characteristics of the display and the adhesion characteristics between the retardation layers are improved, the stiffness of the compound phase difference layer is improved, the warp characteristic is improved, The present invention relates to a polarizing plate comprising a compound retardation layer.

Hereinafter, specific embodiments of the present invention will be described. However, this is merely an example and the present invention is not limited thereto.

<Composite Polarizer>

The composite polarizing plate of the present invention comprises a polarizer and a composite retardation layer disposed on at least one side of the polarizer.

Polarizer

As the polarizer, a polarizer conventionally used in the art can be used, and the kind thereof is not particularly limited. For example, the polarizer may be provided with a polarizing function through a single polarizing film itself as a film form, May be imparted through a polarizing coating formed on the substrate.

Specifically, the polarizer may be one obtained by swelling, dyeing, crosslinking, stretching, washing, and drying a polarizer-forming film containing a polarizer-forming resin. The composition containing the polarizer- Forming a laminated film, and stretching, dyeing, crosslinking, washing with water, and drying the laminated film.

The type of the polarizer-forming resin used in the above polarizing film or polarizing coating is not particularly limited as long as it is a dichroic substance, that is, a resin that can be dyed with iodine. Examples thereof include a polyvinyl alcohol- A polyvinyl alcohol resin, a polyethylene terephthalate resin, an ethylene-vinyl acetate copolymer resin, an ethylene-vinyl alcohol copolymer resin, a cellulose resin, a partially saponified resin thereof, etc. . Of these, polyvinyl alcohol-based resins are preferable as resins for forming polarizers, because they have an excellent effect of enhancing the uniformity of polarization degree in the plane and are excellent in dye affinity for iodine.

The thickness of the polarizer-forming film or the thickness of the film obtained by coating the polarizer-forming resin is not particularly limited. For example, the thickness of the polarizer-forming film may be 10 to 150 탆, The thickness of the polarizing coating formed by coating on the base film may be 3 to 30 占 퐉.

In addition, the composite polarizing plate according to an embodiment of the present invention may use an optical film capable of exhibiting polarization characteristics by coating a liquid crystal in addition to the polarizer described above.

complex Retardation layer

The composite retardation layer according to the present invention is disposed on at least one surface of the polarizer. The composite retardation layer and the polarizer may be in direct contact with each other, or may further include a separate layer therebetween, and may further include, for example, a protective film therebetween.

Further, the compound phase difference layer according to the present invention is laminated in the order of the first retardation layer, the photo-curable adhesive layer and the second retardation layer from the polarizer.

The retardation film laminate according to the present invention has a slope of -514 to -275 with respect to the temperature of the stiffness in the range of 20 to 90 占 폚.

As described above, the first retardation layer and the second retardation layer are used for the OLED display, and excellent flexing characteristics are required when used in a flexible display.

Conventionally, the laminated body of the first retardation layer and the second retardation layer is deficient in the bending property, resulting in folding marks, interface delamination, defective appearance or deformation, and cracks.

Accordingly, the present invention is characterized in that a compound phase difference layer obtained by bonding a first phase difference layer and a second phase difference layer with a photo-curable adhesive is introduced, and a compound phase difference layer having a stiffness gradient of -514 to -275 in a specific temperature range of the compound phase difference layer Thereby solving the above problems.

When a pressure sensitive adhesive is used to bond the first retardation layer and the second retardation layer, a release film (carrier film) is used. In the manufacturing process, a foreign matter inflow due to static electricity occurs when the release film is peeled off.

However, since the composite retardation layer according to the present invention uses a photo-curable adhesive layer, it is unnecessary to remove the release film in the manufacturing process, so that the defect rate can be reduced. Furthermore, since the photocurable adhesive exhibits sufficient adhesion even when it is formed thinner than the pressure-sensitive adhesive layer, the composite polarizing plate can be made thinner and the bending property can be improved accordingly.

By adjusting the composition and content of the photocurable adhesive layer according to the present invention, it is possible to control the adhesive strength, the heat resistance, the durability, the slope of the stiffness with respect to the temperature, and the like.

When the slope of the stiffness is less than -514, a folding trace occurs and interface peeling, appearance defect, or deformation occurs. When the slope of the stiffness exceeds -275, cracks occur.

The thickness of the composite retardation layer is not particularly limited but may be, for example, from 2 to 7 占 퐉. In this case, the flexural properties, adhesion properties between the retardation layers can be improved, The slope of the stiffness may be designed to be -514 to -275.

The composite retardation layer according to the present invention can be bonded to the polarizer by means known in the art, for example, an adhesive, a pressure-sensitive adhesive can be used, and preferably an adhesive can be used.

Retardation layer

The first retardation layer and the second retardation layer according to the present invention are bonded with the photocurable adhesive layer interposed therebetween.

The first retardation layer and the second retardation layer may be those known in the art, respectively. The first retardation layer may be a? / 2 retardation layer and the second retardation layer may be a? / 4 retardation layer, for example, a polymer film that is not drawn or stretched, .

For example, when the first retardation layer and the second retardation layer are made of a liquid crystal layer, the reactive liquid crystal compound (RM) can be used as a liquid crystal compound having optical anisotropy and having optical or thermal crosslinkability. For example, those described in Information Display Vol. 10, No. 1 (Recent Research Trends of Reactive Liquid Crystal Monomers (RM)).

The liquid crystal compound may be coated on the base film to form a liquid crystal film. The coating method is not particularly limited, but pin coating, roll coating, dispensing coating or gravure coating may be used. It is preferable to determine the type and amount of the solvent depending on the coating method.

The base film is not limited to a specific type, but one of the protective films described later can be selected.

Light-curing type Adhesive layer

The photocurable adhesive layer according to the present invention is used in a portion where bonding between the first retardation layer and the second retardation layer of the composite retardation layer is required.

If necessary, the photocurable adhesive layer according to the present invention can be further applied between the polarizer and the protective substrate or between the protective substrate and the complex retardation layer.

The photocurable adhesive layer according to the present invention can be formed of a photocurable adhesive composition capable of performing a photocurable adhesive, and the photocurable adhesive composition can be used without any limitation as long as it can perform a photocurable adhesive. For example, the photocurable adhesive composition may include a photopolymerizable compound, a photoinitiator, and the like.

The photopolymerizable compound may be a photo-radically polymerizable compound or a photo-cationically polymerizable compound known in the art. These may be used alone or in combination of two or more.

Examples of photo-radically polymerizable compounds refer to the photo-radically polymerizable compounds exemplified in the paragraph [0100] of Korean Patent Publication No. 2015-0017446.

As the photo-radical polymerizable compound, a polymer polymerized with the above monomers may also be used.

Examples of photo cationically polymerizable compounds refer to the photo cationic polymerizable compounds exemplified in the paragraph [0101] of Korean Patent Publication No. 2015-0017446.

The photocurable adhesive composition according to an embodiment of the present invention may include an alicyclic epoxy compound and a linear aliphatic epoxy compound in view of adhesion properties and stiffness control.

By adjusting the weight ratio of the content of the alicyclic epoxy compound and the linear aliphatic epoxy compound, adhesion and stiffness of the first and second retardation layers can be more easily controlled. In this respect, the weight ratio of the alicyclic epoxy compound and the linear aliphatic epoxy compound is preferably in the range of 1: 1.5 to 1: 4, more preferably 1: 2 to 1: 4. When the above-mentioned range is satisfied, improvement in interlayer delamination through improved adhesion between retardation layers and improvement in warpage property due to reduction of expansion ratio due to improved stiffness can be exhibited and good light leakage characteristics can be exhibited.

Here, the alicyclic epoxy compound and the linear aliphatic epoxy compound are not particularly limited. For example, the alicyclic epoxy compound may be 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate (3,4 -Epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate)

The linear aliphatic epoxy compounds may be neopentyl glycol diglycidyl ether, 1,2,7,8-Diepoxyoctane, 1,4-butanediol di 1,4-butanediol diglycidyl ether, 2-Ethyl Hexyl Glycidyl Ether, 1,2-Epoxy-9-decene ) And 2,3-epoxy-1- (1-ethoxyethoxy) propane).

The alicyclic epoxy compound and the linear aliphatic epoxy compound may further contain other photo-radical polymerizable compounds and photo-cationic polymerizable compounds as described above, and the content thereof may be 1 to 20 Weight% is preferred.

The content of the examples of the photocationic polymerization initiator, the content of the photopolymerization initiator, and the coating method of the photocurable adhesive composition are cited in the paragraphs [0102] to [0104] of Korean Published Patent Application No. 2015-0017446.

The thickness of the coating of the photocurable adhesive composition is not particularly limited, and can be applied, for example, from 0.01 to 5 탆, preferably from 0.5 to 3 탆.

When the coating thickness of the photocurable adhesive composition is more than 5 탆, it can be applied to a polarizing plate for general display, but cracking of the protective substrate may occur in evaluating the bending property of the flexible display.

Protective film

A protective film may be bonded to at least one surface of the polarizer. For example, when a compound retardation layer is disposed on one side of a polarizer, a protective film can be bonded to the other side. Further, the protective film may be disposed between the compound retardation layer and the polarizer, but is not limited thereto.

Examples of protective films and their contents refer to paragraphs [0111] to [0114] of Korean Laid-open Patent Application No. 2015-0015569.

The thermosetting or ultraviolet curable resin may be a cured layer formed from an aryl resin, a urethane resin, an acryl-urethane resin, an epoxy resin, a silicone resin or the like, but is not limited to a specific film and can be used in consideration of adhesion or durability.

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 thickness of the protective film is 10 to 200 탆, when the polarizer protective film is laminated on both sides of the polarizer, the respective protective films may have the same or different thicknesses.

<Image Display Device>

Further, the composite polarizing plate of the present invention can be usefully applied to an image display device or the like in combination with other conventional structures.

Examples of the image display device include an ordinary electroluminescence display device, an electroluminescence display device, a plasma display device, a field emission display device, an OLED, and the like. When the complex polarizing plate of the present invention is applied to an OLED, It is preferable to be disposed on the viewer side.

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to be illustrative of the invention and are not intended to limit the scope of the claims. It will be apparent to those skilled in the art that such variations and modifications are within the scope of the appended claims.

Production Example 1

A polyvinyl alcohol film (PS 7500, Kuraray) having an average degree of polymerization of 2,400 and a saponification degree of 99.9% or more was immersed in water (deionized water) at 30 ° C for 2 minutes to swell a 75 μm thick polyvinyl alcohol film And 2% by weight of potassium iodide, and dyed for 4 minutes in an aqueous solution for dyeing at 30 DEG C. After dyeing, 2% by weight of potassium iodide and 3.7% by weight of boric acid and 50% by weight of potassium iodide Lt; 0 &gt; C for 2 minutes for crosslinking. And the cumulative stretching ratio until each swelling / dyeing / crosslinking / washing step was 5.5 times.

Production Example 2

A novolene FLX80E4 (Sumitomo Chemical Co., Ltd.) was disposed on both sides of a resin layer of a novolene W151 (Sumitomo Chemical Co., Ltd.) to produce a three-layer structure base film by coextrusion molding using a multilayer extrusion molding machine, and polyvinyl alcohol powder A 3% by weight aqueous solution was prepared by heating Z-200 (manufactured by Nippon Synthetic Co., Ltd.) to 90 ° C and then mixed with 2% by weight of polyvinyl alcohol powder at a weight ratio of 1% To obtain a coating liquid for forming a primer layer, and a polyvinyl alcohol powder PVA124 (Kuraray Co., Ltd.) was heated to 90 DEG C to prepare an aqueous solution of 8 wt% to prepare a coating liquid for forming a polyvinyl alcohol- A primer layer was coated on the corona-treated surface using a microgravure coater and dried at 80 DEG C for 3 minutes to form a 0.2 mu m primer layer, thereby forming a poly Coating a carbonyl alcohol-based coating solution, which was continuously form a series of 10㎛ thick polyvinyl alcohol resin layer and dried at 90 ℃ 5 minutes.

The obtained multilayered film was stretched 5.8 times with a roll of 160 DEG C, immersed in pure water at 60 DEG C for 1 minute, dyed in a dyeing solution of iodine and potassium iodide for 3 minutes, and then dyed with 75 g of boric acid and potassium iodide ° C for 10 minutes, followed by washing with pure water at 10 ° C, followed by drying at 80 ° C for 5 minutes to prepare a polyvinyl alcohol polarizer having a thickness of 3.8 μm.

Example  One

(A) Preparation of photocurable adhesive composition

80% by weight of neopentyl glycol diglycidyl ether of a linear aliphatic epoxy compound of Aldrich, and 4% by weight of a cationic photoinitiator CPI-110A of Sanfrasa were mixed to prepare an adhesive composition The weight ratio of the alicyclic epoxy compound to the linear aliphatic epoxy compound was 1: 4.

(B) Production of a composite retardation layer

To the UV curing in a high-pressure mercury lamp (UVA cumulative dose 500mJ / cm ²⁾ by joining so that 3㎛ the above-prepared photo-curing type adhesive composition between the λ / 2 phase difference layer and a λ / 4 retardation layer to form a composite phase difference layer .

(C) Production of Polarizing Plate

A triacetylcellulose-based film (FUJI) was coated on one side of the polarizer of Preparation Example 1 and coated with an aqueous adhesive, and on the other side, the side of the? / 2 retardation layer of the composite retardation layer was coated with a film- Respectively. A polarizing plate was produced by further bonding a film-type acrylic pressure-sensitive adhesive to the side of the? / 4 retardation layer of the above bonded structure.

2 is a schematic cross-sectional view of a composite polarizer plate.

Example  2

 Except that 30% by weight of a diisocyanate cyclic epoxy compound CEL 2021P and 70% by weight of neopentyl glycol diglycidyl ether of linear aliphatic epoxy compound of Aldrich Co. were used to prepare an adhesive composition, and the same polarizing plate as in Example 1 was prepared And the weight ratio of the alicyclic epoxy compound to the linear aliphatic epoxy compound was 1: 2.3.

Example  3

70 wt% of neopentyl glycol diglycidyl ether of linear aliphatic epoxy compound of Aldrich, and 10 wt% of 1,2,7,8-diepoxy octane were blended with 20 wt% of CEL 2021P, The same polarizing plate as in Example 1 was prepared except that the composition was prepared. The weight ratio of the alicyclic epoxy compound to the linear aliphatic epoxy compound was 1: 4.

Example  4

Except that 20% by weight of the diacetyl cyclic epoxy compound CEL 2021P and 80% by weight of the linear aliphatic epoxy compound 1,2,7,8-diepoxy octane of Aldrich Co. were used to prepare an adhesive composition. The weight ratio of the alicyclic epoxy compound to the linear aliphatic epoxy compound was 1: 4.

Example  5

20% by weight of CEL 2021P as a diisocyanate type epoxy compound, and 80% by weight of a linear aliphatic epoxy compound of 1,4-butanediol diglycidyl ether of Aldrich, to prepare an adhesive composition A polarizer was prepared. The weight ratio of the alicyclic epoxy compound and the linear aliphatic epoxy compound was 1: 4.

Example  6

A polarizer was prepared in the same manner as in Example 1, except that 20% by weight of the dicellulose alicyclic epoxy compound CEL 2021P and 80% by weight of the linear aliphatic epoxy compound 2-ethylhexyl glycidyl ether of Aldrich Co. were used to prepare an adhesive composition The weight ratio of the alicyclic epoxy compound to the linear aliphatic epoxy compound is 1: 4.

Example  7

Except that 20% by weight of the diacetyl cyclic epoxy compound CEL 2021P and 80% by weight of the linear aliphatic epoxy compound 1,2-epoxy-9-decene by Aldrich Co. were used to prepare an adhesive composition, The weight ratio of the alicyclic epoxy compound to the linear aliphatic epoxy compound was 1: 4.

Example  8

Except that 20% by weight of the diacetyl cyclic epoxy compound CEL 2021P and 80% by weight of the linear aliphatic epoxy compound 2,3-epoxy-1- (1-ethoxyethoxy) propane of Aldrich Co. were used to prepare an adhesive composition The same polarizing plate as in Example 1 was prepared, and the weight ratio of the alicyclic epoxy compound to the linear aliphatic epoxy compound was 1: 4.

Example  9

70 wt% of neopentyl glycol diglycidyl ether of a linear aliphatic epoxy compound of Aldrich, 10 wt% of an aromatic epoxyserosyl diglycidyl ether of aromatic aldrich, and 20 wt% of a diisocyanate cyclic epoxy compound CEL 2021P To prepare the same polarizing plate as in Example 1, except that the weight ratio of the alicyclic epoxy compound to the linear aliphatic epoxy compound was 1: 3.5.

Example  10

20 wt% of a diisocyanate cyclic epoxy compound CEL 2021P, 70 wt% of a linear aliphatic epoxy compound of Aldrich, neopentyl glycol diglycidyl ether, 10 wt% of an acrylate monomer glycidyl methacrylate of aromatic aldrich, Except that 4 wt% of the radical photoinitiator Irg184 was blended to prepare an adhesive composition. The weight ratio of the alicyclic epoxy compound to the linear aliphatic epoxy compound was 1: 3.5.

Example  11

20% by weight of a diacetyl cyclic epoxy compound CEL 2021P, 70% by weight of a linear aliphatic epoxy compound of Aldrich, neopentyl glycol diglycidyl ether, 10% by weight of an aromatic epoxy of aromatic aldrich, and an acrylate monomer glycidyl methacrylate 10% by weight, and 4% by weight of a radical photoinitiator Irg184 of Ciba Co., Ltd. to prepare an adhesive composition. The weight ratio of the alicyclic epoxy compound and the linear aliphatic epoxy compound in this case was 1: 3.

Example  12

A polarizing plate was prepared in the same manner as in Example 1 except that the adhesive had a thickness of 5 탆.

Example  13

A polarizing plate was produced in the same manner as in Example 1, except that the adhesive had a thickness of 1 mu m.

Example  14

Except that the polarizer of Preparation Example 2 was used as the polarizer and a triacetylcellulose film (FUJI) was bonded to the side of the polarizer on which the polyvinyl alcohol-based resin layer was formed. .

Comparative Example  One

Except that 10% by weight of the diacetyl cyclic epoxy compound CEL 2021P and 90% by weight of neopentyl glycol diglycidyl ether of linear aliphatic epoxy compound of Aldrich Co. were used to prepare an adhesive composition, and the same polarizing plate as in Example 1 was prepared The weight ratio of the alicyclic epoxy compound to the linear aliphatic epoxy compound was 1: 9.

Comparative Example  2

 Except that 70% by weight of the diacetyl cyclic epoxy compound CEL 2021P and 30% by weight of neopentyl glycol diglycidyl ether of linear aliphatic epoxy compound of Aldrich Co. were used to prepare an adhesive composition, and the same polarizing plate as in Example 1 was prepared And the weight ratio of the alicyclic epoxy compound to the linear aliphatic epoxy compound was 1: 0.4.

Comparative Example  3

20% by weight of neopentyl glycol diglycidyl ether of linear aliphatic epoxy compound of Aldrich, and 10% by weight of 1,2,7,8-diepoxy octane were mixed with 70% by weight of CEL 2021P, The same polarizing plate as in Example 1 was prepared except that the composition was prepared. The weight ratio of the alicyclic epoxy compound to the linear aliphatic epoxy compound was 1: 0.4.

Comparative Example  4

60% by weight of a diacetyl cyclic epoxy compound CEL 2021P, and 40% by weight of neopentyl glycol diglycidyl ether of a linear aliphatic epoxy compound of Aldrich, were mixed to prepare the same polarizer as in Example 1 The weight ratio of the alicyclic epoxy compound to the linear aliphatic epoxy compound was 1: 0.7.

Comparative Example  5

Except that 50% by weight of a diisocyanate cyclic epoxy compound CEL 2021P and 50% by weight of neopentyl glycol diglycidyl ether of a linear aliphatic epoxy compound of Aldrich Co. were used to prepare an adhesive composition, and the same polarizing plate as in Example 1 was prepared The weight ratio of the alicyclic epoxy compound to the linear aliphatic epoxy compound is 1: 1.

Comparative Example  6

15% by weight of a multifunctional acrylate monomer, 0.3% by weight of a photopolymerization initiator (Irgacure 500, manufactured by Mitsubishi Rayon Co., Ltd.) was added to the acrylic copolymer at 70% by weight of butyl acrylate, 20% by weight of methyl artriate and 10% (KBM-403, manufactured by Shinetsu Chemical Co., Ltd.) was added to the acrylic pressure-sensitive adhesive composition to prepare an acrylic pressure-sensitive adhesive composition. The pressure-sensitive adhesive composition thus prepared was applied to a separate film having a thickness of 80 占 퐉 and dried to produce an adhesive film having an acrylic pressure-sensitive adhesive layer having a thickness of 5 占 퐉.

The adhesive layer was repeatedly transferred to the? / 2 retardation layer of the compound retardation layer to form an acrylic pressure sensitive adhesive layer having a thickness of 20 占 퐉, and a polarizing plate same as Example 1 was prepared, except that? / 4 retardation layer was bonded thereon.

Comparative Example  7

The same polarizing plate as in Comparative Example 6 was prepared except that the thickness of the acrylic pressure sensitive adhesive layer was changed to 5 占 퐉.

Comparative Example  8

A polarizing plate was prepared in the same manner as in Example 1, except that the adhesive had a thickness of 7 탆.

Stiffness  Tilt measurement

The composite retardation layer prepared in Examples and Comparative Examples was cut into a size of 2 mm x 50 mm and then subjected to a measurement with a kinetic thermal characteristic analyzer (Q-800, TA Instrument) at a gage distance of 15 mm at 30 ° C to 80 ° C And the stiffness was evaluated. At this time, the stiffness at 30 DEG C, 50 DEG C, and 80 DEG C was taken to determine the slope of the stiffness. The slope of the stiffness was obtained from the graph showing the temperature (° C) on the X axis and the magnitude of the stiffness according to the temperature on the Y axis, and the slope of the stiffness was obtained by linear regression analysis. Stiffness gradients of Examples 1, 12, 13 and 7 are shown in the temperature-stiffness graph of FIG.

Hereinafter, the composition contents of Examples 1 to 14 are expressed as% by weight. division The alicyclic epoxy compound (A)
(weight%) The linear aliphatic epoxy compound (B)
(weight%) The aromatic epoxy compound (C)
(weight%) Acrylate (D)
(weight%) (A) :( B) Stiffness
inclination ingredient content ingredient content ingredient content ingredient content Example 1 A-1 20 B-1 80 - - - - 1: 4.0 -408 Example 2 A-1 30 B-1 70 - - - - 1: 2.3 -423 Example 3 A-1 20 B-1 / B-2 70/10 - - - - 1: 4.0 -376 Example 4 A-1 20 B-2 80 - - - - 1: 4.0 -351 Example 5 A-1 20 B-3 80 - - - - 1: 4.0 -408 Example 6 A-1 20 B-4 80 - - - - 1: 4.0 -335 Example 7 A-1 20 B-5 80 - - - - 1: 4.0 -334 Example 8 A-1 20 B-6 80 - - - - 1: 4.0 -325 Example 9 A-1 20 B-1 70 C-1 10 - - 1: 3.5 -453 Example 10 A-1 20 B-1 70 - - D-1 10 1: 3.5 -348 Example 11 A-1 20 B-1 60 C-1 10 D-1 10 1: 3.0 -451 Example 12 A-1 20 B-1 80 - - - - 1: 4.0 -514 Example 13 A-1 20 B-1 80 - - - - 1: 4.0 -275 Example 14 A-1 20 B-1 80 - - - - 1: 4.0 -408

Hereinafter, the composition contents of Comparative Examples 1 to 8 were expressed as% by weight. division Alicyclic epoxy compound
(weight%) Linear aliphatic epoxy compound
(weight%) Aromatic epoxy compound
(weight%) Acrylate
(weight%) (A) :( B) Stiffness
inclination ingredient content ingredient content ingredient content ingredient content Comparative Example 1 A-1 10 B-1 90 - - - - 1: 9.0 -251 Comparative Example 2 A-1 70 B-1 30 - - - - 1: 0.4 -608 Comparative Example 3 A-1 70 B-1 / B-2 20/10 - - - - 1: 0.4 -583 Comparative Example 4 A-1 60 B-1 40 - - - - 1: 0.7 -578 Comparative Example 5 A-1 50 B-1 50 - - - - 1: 1.0 -562 Comparative Example 6 B'-1 - -215 Comparative Example 7 B'-1 - -110 Comparative Example 8 A-1 20 B-1 80 - - - - 1: 4.0 -660

A-1: CEL 2021P (Daicel)

B-1: Neopentyl glycol diglycidyl ether

B-2: 1,2,7,8-Diepoxyoctane

B-3: 1,4-butanediol diglycidyl ether

B-4: 2-ethylhexyl glycidyl ether

B-5: 1,2-epoxy-9-decene

B-6: 2,3-Epoxy-1- (1-ethoxyethoxy) propane

B'-1: Acrylic adhesive

C-1: Resosin ol diglycidyl ether

D-1: glycidyl methacrylate

Evaluation test

(1) Cross Cut

For the composite polarizing plate of Examples and Comparative Examples, the interlaminar adhesion (whether delamination between layers) of the composite retardation layer was tested according to the standard of ASTM D 3359. 11 pieces of cutting lines were formed in the longitudinal direction and the transverse direction at intervals of 1 mm on the surface of the compound phase difference layer to form 100 pieces of 1 mm ² eye pieces and then a cellophane tape was stuck on the surface thereof and then peeling was repeated three times The average peel number was evaluated and evaluated according to the following criteria.

OK: Number of peelings 0 to less than 10

NG: Number of peelings 10 or more

(2) Light beam  evaluation

The prepared polarizer was adhered to the glass using a film type adhesive, and a silver reflector was attached to the opposite side of the polarizer adhered surface. The adherent was then placed in an oven at 85 ° C for 24 hours and taken out of the chamber.

○: No light leakage

X: Light is present

(3) Evaluation of bending

Using a bending test machine (MIT evaluation), repeated bending tests were performed with a width of 10 mm, a length of 150 mm, and a radius of 3 mm, and the degree of cracking and peeling between film layers were observed during repeated bending tests up to 50,000 times.

[Crack]

○: No cracks in protective substrate

?: Within 2 mm of the crack at the end portion of the protective substrate

X: crack at the front side of the protective substrate

[Delamination]

○: No delamination

?: End peeling distance of protective substrate / adhesive protective substrate within 2 mm

X: Protective Substrate / Adhesive Protective Substrate The end peel distance exceeds 2 mm

division Light-curing type
Adhesive thickness (탆) Cross Cut Rating light Bending evaluation Crack Delamination Example 1 3 OK (0) ○ △ ○ Example 2 3 OK (3) ○ △ ○ Example 3 3 OK (1) ○ △ ○ Example 4 3 OK (1) ○ △ ○ Example 5 3 OK (1) ○ △ ○ Example 6 3 OK (2) ○ △ ○ Example 7 3 OK (3) ○ △ ○ Example 8 3 OK (4) ○ △ ○ Example 9 3 OK (5) ○ △ ○ Example 10 3 OK (3) ○ △ ○ Example 11 3 OK (3) ○ △ ○ Example 12 5 OK (0) ○ △ ○ Example 13 One OK (7) ○ ○ ○ Example 14 3 OK (2) ○ △ ○

division Adhesive thickness (탆) Photocurable adhesive thickness (탆) Cross Cut Rating light Bending evaluation Crack Delamination Comparative Example 1 - 3 OK (3) X ○ ○ Comparative Example 2 - 3 NG (28) ○ X X Comparative Example 3 - 3 NG (27) ○ X X Comparative Example 4 - 3 NG (15) ○ X X Comparative Example 5 - 3 NG (12) ○ X X Comparative Example 6 20 - OK (8) X X X Comparative Example 7 5 - NG (10) X △ X Comparative Example 8 - 7 OK (0) ○ X ○

Referring to Tables 3 and 4, the embodiments are excellent in both cross cut, light leakage evaluation, and bending evaluation, but the comparative examples are not excellent in both cross cut, light leakage evaluation and bending evaluation.

Claims (11)

A polarizer; And
And a compound retardation layer disposed on at least one surface of the polarizer and laminated from the polarizer in order of a first retardation layer, a light curable adhesive layer, and a second retardation layer,
The composite retardation layer has a slope of -514 to -275 with respect to the temperature of the stiffness in the range of 20 to 90 캜,
Wherein the photocurable adhesive comprises an alicyclic epoxy compound and a linear aliphatic epoxy compound.
The composite polarizer of claim 1, wherein the first retardation layer is a? / 2 retardation layer and the second retardation layer is a? / 4 retardation layer.
delete The composite polarizing plate according to claim 1, wherein the photocurable adhesive has a weight ratio of the alicyclic epoxy compound and the linear aliphatic epoxy compound of 1: 1.5 to 4.
The composite polarizing plate according to claim 1, wherein the alicyclic epoxy compound is 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate.
The composition of claim 1, wherein the linear aliphatic epoxy compound is selected from the group consisting of neopentyl glycol diglycidyl ether, 1,2,7,8-Diepoxyoctane, 1,4-butanediol diglycidyl ether, 2-ethyl hexyl glycidyl ether, 1,2-epoxy-9-decene (1,2 -Epoxy-9-decene, and 2,3-epoxy-1- (1-ethoxyethoxy) propane. Complex polarizer.
The composite polarizing plate according to claim 1, wherein the photocuring adhesive layer has a coating thickness of 0.01 to 5 占 퐉.
The composite polarizer of claim 1, wherein the thickness of the composite retardation layer is 2 to 7 占 퐉.
The composite polarizer of claim 1, wherein the polarizer comprises a polarizing film, or a polarizing coating on a substrate film and a substrate film.
The composite polarizer of claim 1, wherein the composite retardation layer is disposed on one side of the polarizer and the protective film is bonded on the other side.
An image display device comprising the composite polarizing plate of any one of claims 1, 2 and 4 to 10.

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