KR20150093313A - Adhesive composition and complexed polarization plate using the same - Google Patents

Abstract

The present invention relates to an adhesive composition used in a bond of a polarizer and a patterned phase difference layer and, more specifically, to an adhesive composition comrpising a photopolymerizable compound containing at least one monomer of chemical formula 1 and 2, and a photopolymerization initiator, thereby improving bonding force between a polarizer and a patterned phase difference layer, and not only improving heat resistance and moist heat resistance, but having an excellent three-dimensional effect.

Description

TECHNICAL FIELD [0001] The present invention relates to an adhesive composition and a composite polarizer using the adhesive composition.

The present invention relates to an adhesive composition and a composite polarizer using the same.

In a display such as a liquid crystal display for stereoscopic image implementation, a patterned retardation film is often included. The patterned retardation film realizes a stereoscopic image by configuring the optical axes of the respective pattern regions in different directions so that images transmitted to the left and right eyes of the viewer wearing polarized glasses are different.

The patterned retardation film can be usually formed by forming an alignment film on a glass substrate and coating and orienting a liquid crystal on the alignment film. The photoreactive liquid crystal material is oriented on the alignment layer and then crosslinked by light irradiation such as ultraviolet rays to form a polymer liquid crystal film. At this time, the retarder pattern functions in accordance with the alignment direction of the liquid crystal in accordance with the surface orientation of the alignment film.

The patterned retardation film is usually bonded to one side of a polarizing plate via an adhesive or a pressure-sensitive adhesive, and is recently bonded to one side of a polyvinyl alcohol polarizer for further thin film lightening.

If the patterned retardation film is inferior in adhesion between the polarizing plate and the polarizer, deformation may occur during handling or during use in the process, and peeling or bumping may occur when the film is exposed to high temperature and high humidity for a long time. In addition, a conventional polyvinyl alcohol polarizer can shrink in the stretching direction, so that the retardation differs depending on the position of the retardation layer, and the 3D stereoscopic effect may be lowered.

Accordingly, there is a demand for development of an excellent adhesive having excellent bonding strength, excellent functions such as resistance to water temperature and resistance to humidity, and the like.

Korean Patent Laid-Open Publication No. 2013-0028881 discloses a film pattern retarder, a film pattern retarder, and a polarizing plate and an image display device having the film pattern retarder.

Korea Patent Publication No. 2013-0028881

An object of the present invention is to provide an adhesive composition capable of remarkably improving the bonding force between a polarizer and a patterned retardation layer.

It is an object of the present invention to provide a composite polarizing plate bonded through the above adhesive composition.

1. used for bonding a polarizer and a patterned retardation layer,

An adhesive composition comprising a photopolymerizable compound containing at least one monomer of the following formulas (1) and (2) and a photopolymerization initiator:

[Chemical Formula 1]

(Wherein,

X is a radical reactive functional group;

R ₁ is a direct bond or an alkyl group having 2 to 12 carbon atoms which is substituted or unsubstituted with a hydroxy group, the alkyl group may be interrupted by an oxygen atom;

R ₂ and R ₃ independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, -OR ₄ , -NR ₅ R ₆ or -SR ₇ ;

R ₄ to R ₇ independently represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms or an aryl group having 6 to 18 carbon atoms)

(2)

(Wherein,

R ₁ is a hydrogen atom, a hydroxy group, an alkyl group having 1 to 12 carbon atoms, OR ₄ , or an aryl group having 6 to 18 carbon atoms, wherein the aryl group may be substituted with an acryloxy group;

R ₄ is an acrylic alkyl group or an acrylic oxyalkyl group having 1 to 12 carbon atoms of an alkyl group substituted or unsubstituted with a hydroxyl group, the alkyl group may be interrupted by an oxygen atom;

R ₂ and R ₃ are independently of each other a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or OR ₅ ;

R ₅ is an alkyl group having 1 to 6 carbon atoms, an acryl group, or an acryloxyalkyl group having 1 to 10 carbon atoms in the alkyl group, wherein the alkyl group and the acryloxyalkyl group may be interrupted by an oxygen atom and may be substituted with a hydroxy group.

2. The adhesive composition according to 1 above, wherein the monomers of the general formulas (1) and (2) have a total content of 30% by weight or more based on the total weight of the total monomers.

3. The adhesive composition according to 1 above, further comprising at least one of a hydroxy group-containing acrylic monomer and a carboxyl group-containing acrylic monomer.

4. The adhesive composition according to 3 above, wherein the total content of the hydroxy group-containing acrylic monomer and the carboxyl group-containing acrylic monomer is 10 to 70% by weight based on the total weight of the total monomers.

5. Polarizer, and

And a patterned retardation layer bonded to one surface of the polarizer through the adhesive composition of any one of [1] to [4] above.

6. The composite polarizer of claim 5, wherein the polarizer is formed by bonding a protective film or a film having a function of a retardation film to a surface opposite to a surface bonded to the patterned retardation layer.

7. The composition according to item 5, wherein the patterned retardation layer contains at least one reactive liquid crystal monomer selected from the group consisting of cinnamate monofunctional monomers, phenylbenzoate monofunctional monomers and phenylbenzoate based bifunctional monomers, And a liquid crystal coating layer.

8. In the above-mentioned 7, when the liquid crystal coating layer of the patterned retardation layer contains a phenyl benzoate-based monomer, it is bonded to an adhesive composition containing a monomer of the formula (1)

And a cinnamate-based monomer is bonded to an adhesive composition containing a monomer represented by the general formula (2).

9. The composite polarizer of claim 5, wherein the patterned retardation layer does not include an alignment film.

10. An image display device comprising the composite polarizing plate of the above 5.

The pressure-sensitive adhesive composition of the present invention remarkably improves the bonding force between the polarizer and the patterned retardation layer when the polarizer and the patterned retardation layer are bonded to produce a composite polarizing plate.

The composite polarizer laminated with the pressure-sensitive adhesive composition of the present invention is excellent in heat resistance and heat and humidity resistance, and peeling and bending phenomenon are suppressed even when exposed to high temperature and high humidity conditions for a long time.

The composite polarizing plate bonded with the pressure-sensitive adhesive composition of the present invention has a polarization function and an improved 3D stereoscopic effect at the same time.

The present invention relates to an adhesive composition used for bonding a polarizer and a patterned retardation layer, which comprises a photopolymerizable compound containing at least one monomer of the general formulas (1) and (2) and a photopolymerization initiator, The present invention relates to an adhesive composition which not only improves the bonding strength between the thermoplastic resin and the thermosetting resin, but also improves the heat resistance and the heat and humidity resistance.

Hereinafter, the present invention will be described in detail.

≪ Adhesive composition >

The adhesive composition of the present invention is an adhesive composition used for producing a composite polarizing plate by bonding a polarizer and a patterned retardation layer, and is interposed between a polarizer and a patterned retardation layer.

The patterned retardation layer includes a liquid crystal coating layer formed on the side in contact with the polarizer.

The liquid crystal coating layer may be formed of a composition for forming a liquid crystal coating layer including a reactive liquid crystal monomer (RM) commonly used in the art.

Representative examples of the reactive liquid crystal monomer include a cinnamate monofunctional monomer, a phenylbenzoate monofunctional monomer, and a phenylbenzoate based bifunctional monomer.

The adhesive composition of the present invention comprises a photopolymerizable compound containing at least one monomer of formula (I) and (II)

[Chemical Formula 1]

(Wherein,

X is a radical reactive functional group;

R ₁ is a direct bond or an alkyl group having 2 to 12 carbon atoms which is substituted or unsubstituted with a hydroxy group, the alkyl group may be interrupted by an oxygen atom;

R ₂ and R ₃ independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, -OR ₄ , -NR ₅ R ₆ or -SR ₇ ;

R ₄ to R ₇ independently represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms or an aryl group having 6 to 18 carbon atoms)

(2)

(Wherein,

R ₁ is a hydrogen atom, a hydroxy group, an alkyl group having 1 to 12 carbon atoms, OR ₄ , or an aryl group having 6 to 18 carbon atoms, wherein the aryl group may be substituted with an acryloxy group;

R ₄ is an acrylic alkyl group or an acrylic oxyalkyl group having 1 to 12 carbon atoms of an alkyl group substituted or unsubstituted with a hydroxyl group, the alkyl group may be interrupted by an oxygen atom;

R ₂ and R ₃ are independently of each other a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or OR ₅ ;

R ₅ is an alkyl group having 1 to 6 carbon atoms, an acryl group, or an acryloxyalkyl group having 1 to 10 carbon atoms in the alkyl group, wherein the alkyl group and the acryloxyalkyl group may be interrupted by an oxygen atom and may be substituted with a hydroxy group.

The radical-reactive functional group is a functional group capable of reacting with a radical, and is not particularly limited, and examples thereof include an acrylic group and an acryloxy group. Acrylic and acryloxy groups herein are concepts that include methacrylic groups and methacryloxy groups.

The heteroatom is not particularly limited and may be, for example, oxygen, nitrogen, phosphorus, sulfur, and the like.

The adhesive composition of the present invention includes a photopolymerizable compound containing at least one monomer of the above formulas (1) and (2), whereby bonding force can be remarkably improved when a polarizing plate and a patterned retardation layer are bonded to each other to produce a composite polarizing plate. This is because the monomers of formulas (1) and (2) have the same macromolecular structure as the reactive liquid crystal monomers constituting the liquid crystal coating layer, thereby maximizing the pi-phi interaction between the monomers.

The monomer represented by the formula (1) is not particularly limited and includes, for example, at least one acrylic monomer of the following formulas (3-a) to (3-h).

[Formula 3-a]

[Formula 3-b]

[Chemical Formula 3-c]

[Chemical formula 3-d]

[Formula 3-e]

[Chemical Formula 3-f]

[Formula 3-g]

[Chemical Formula 3-h]

The monomer of formula (2) is not particularly limited, and examples thereof include at least one acrylic monomer selected from the group consisting of the following formulas 4-a to 4-i.

[Chemical Formula 4-a]

[Formula 4-b]

[Chemical formula 4-c]

[Chemical formula 4-d]

[Chemical Formula 4-e]

[Chemical Formula 4-f]

[Formula 4-g]

[Chemical Formula 4-h]

[Chemical formula 4-i]

The content of the monomers of the formulas (1) and (2) is not particularly limited and may be, for example, 30% by weight or more of the total weight of the total monomers. When the content is less than 30% by weight, adhesion with the liquid crystal layer may be insufficient. But it may be contained in an amount of preferably 30 to 90% by weight in view of simultaneously enhancing adhesion between the liquid crystal layer and the polarizer.

Since the monomers of formulas (1) and (2) have the same macromolecular structure as the reactive liquid crystal monomers contained in the liquid crystal coating layer contained in the patterned retardation layer, they can maximize the bonding force. Therefore, the mixing ratio can be determined depending on the kind of the reactive liquid crystal monomer have. Specifically, when the reactive liquid crystal monomer is a phenylbenzoate monomer, the compound of Formula 1: Formula 2 is contained in a ratio of 10: 0, and when the reactive liquid crystal monomer is a cinnamate monomer, a ratio of 0:10 ≪ / RTI > When the reactive liquid crystal monomer contains a phenylbenzoate-based monomer and a cinnamate-based monomer, the monomer of the formula (1) and the monomer of the formula (2) may be contained in the same proportion. In such a case, the effect of improving the bonding force can be maximized.

The photopolymerizable compound according to the present invention may further comprise at least one of a hydroxy group-containing acrylic monomer and a carboxyl group-containing acrylic monomer.

The hydroxyl group-containing acrylic monomers and the carboxyl group-containing acrylic monomers further improve the adhesion between the polarizer and the patterned retardation layer. This is considered to be due to the fact that the hydroxyl group and the carboxyl group are hydrogen bonded to polar groups contained in the liquid crystal coating layer of the polarizer surface polarizing layer and the patterned retardation layer and the wettability of the adhesive composition is improved.

The hydroxy group-containing acrylic monomer is not particularly limited, and examples thereof include at least one monomer selected from the group consisting of the following formulas (5-a) to (5-j).

[Formula 5-a]

[Chemical Formula 5-b]

[Chemical Formula 5-c]

[Chemical formula 5-d]

[Chemical Formula 5-e]

[Chemical Formula 5-f]

[Formula 5-g]

[Chemical Formula 5-h]

[Chemical Formula 5-i]

[Chemical formula 5-j]

The carboxyl group-containing acrylic monomer is not particularly limited and includes, for example, at least one monomer selected from the group consisting of the following formulas (6) to (6-e).

[Chemical Formula 6-a]

[Chemical Formula 6-b]

[Chemical formula 6-c]

[Chemical formula 6-d]

[Chemical Formula 6-e]

The content of the hydroxy group-containing acrylic monomer and the carboxyl group-containing acrylic monomer is not particularly limited and may be, for example, 10 to 70% by weight of the total weight of the total monomers. If the content is less than 10% by weight, the adhesion with the liquid crystal coating layer is sufficient, but the adhesion with the polarizer is decreased. As a result, the bonding force between the polarizer and the patterned retardation layer may be deteriorated. Can sufficiently be secured, but the adhesion with the liquid crystal coating layer may be lowered.

The adhesive composition of the present invention further comprises a photopolymerization initiator.

The photopolymerization initiator is not particularly limited, and examples thereof include radical photopolymerization initiators such as acetophenone, benzophenone, thioxanthone, benzoin and benzoin alkyl ether. These may be used alone or in combination of two or more.

Specific examples thereof include acetophenone, hydroxydimethylacetophenone, dimethylaminoacetophenone, dimethoxy-2-phenylacetophenone, 3-methylacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2- Methoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 4-hydroxycyclophenyl ketone, Propan-1-one, 4- (2-hydroxyethoxy) phenyl-2-methyl-1- - (hydroxy-2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4-diaminobenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, anthraquinone, 2- Anthraquinone, 2-ethyl anthraquinone, 2-t-butyl anthraquinone, 2-amino anthraquinone, 2-methyl thioxanthone, 2-ethyl thioxanthone, 2-chlorothioxanthone, Oxanone, 2,4-diethylthioxanthone, benzoin, benzoin methyl ether, Benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, benzyl dimethyl ketal, diphenyl ketone benzyl dimethyl ketal, acetophenone dimethyl ketal, p- 4,6-trimethylbenzoyldiphenylphosphine oxide, fluorene, triphenylamine, carbazole, and the like, but are not limited thereto.

The available products available on the market include darocur 1173, darocur 4265, darocur BP, darocur TPO, darocur MBF, iracacure 184, irgacure 500, irgacure 2959, irgacure 754, irgacure 651, irgacure 369, irgacure 907, irgacure 1300, irgacure 754, 819, irgacure 2022, irgacure 819DW, irgacure 2100, irgacure 784, irgacure 250, and the like. These may be used alone or in combination of two or more.

The content of the photopolymerization initiator is not particularly limited and may be, for example, 0.1 to 10 parts by weight, preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the photopolymerizable compound. If the content of the photopolymerization initiator is less than 0.1 parts by weight, the curing rate may be slowed and sufficient curing may be difficult to proceed. If the content is more than 10 parts by weight, the durability of the adhesive layer may be deteriorated.

The adhesive composition of the present invention may further include polyfunctional acrylic monomers known in the art within the scope of not impairing the object of the present invention.

Examples of the polyfunctional acrylic monomer include, but are not limited to, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, (Meth) acrylate such as propane tri (meth) acrylate, propylene oxide modified trimethylolpropane tri (meth) acrylate, tris (2-hydroxyethyl) isocyanurate tri Trifunctional monomers such as glycerol tri (meth) acrylate; Tetrafunctional monomers such as diglycerin tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, ditrimethylol propane tetra (meth) acrylate, and tetramethylol propane tetra (meth) acrylate; Pentafunctional monomers such as dipentaerythritol penta (meth) acrylate and propionic acid-modified dipentaerythritol penta (meth) acrylate; Hexafunctional monomers such as dipentaerythritol hexa (meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) acrylate, and isocyanate-modified urethane hexa (meth) acrylate. These may be used alone or in combination of two or more.

The content of the polyfunctional acrylic monomer is not particularly limited and may be, for example, 0.1 to 5 parts by weight based on 100 parts by weight of the photopolymerizable compound.

<Composite Polarizer>

The present invention also provides a composite polarizing plate produced using the adhesive composition.

The composite polarizing plate of the present invention comprises a polarizer and a patterned retardation layer bonded to one surface of the polarizer through the adhesive composition.

In the composite polarizing plate of the present invention, the polarizer and the patterned retardation layer are bonded to each other through the adhesive composition, and the bonding strength is excellent.

Polarizers are generally used in the display field and are not limited to specific ones as long as they can polarize incident light. For example, a film made of polyvinyl alcohol (PVA) may be prepared by dyeing iodine or a dichroic dye and stretching it in a predetermined direction. And a protective film may be adhered to the opposite surface of the surface bonded with the patterned retardation layer.

The structure of the patterned retardation layer is not particularly limited, and may include a structure commonly used in the art. For example, it may have a structure in which a substrate, an alignment film, and a liquid crystal coating layer are laminated in this order, or may be a structure that does not include an alignment film.

The patterned retardation layer is bonded so that the liquid crystal coating layer faces the polarizer.

The base material is not particularly limited as long as it is formed of a material excellent in transparency, mechanical strength, thermal stability, water shielding property, phase difference uniformity, isotropy, etc. For example, a polyolefin resin, a polyester resin, a cellulose resin, , An acrylic resin, a styrene resin, a vinyl chloride resin, an amide resin, an imide resin, a polyether sulfone resin, a sulfone resin, a polyether sulfone resin, a polyetheretherketone resin, A substrate formed of at least one material selected from the group consisting of a vinyl alcohol resin, a vinylidene chloride resin, a vinyl butyral resin, an allylate resin, a polyoxymethylene resin and an epoxy resin can be used.

When the patterned retardation layer comprises an alignment film, the alignment film is formed by a method of coating on a substrate a composition for forming an alignment film commonly used in the art, imparting orientation, and then patterning the film so as to have different orientation directions .

The orientation imparting method includes a rubbing method, a photo alignment method, and the like. The patterning method can be performed by a plurality of exposure steps using a photomask, but the present invention is not limited thereto.

The light used for exposure is not particularly limited, and for example, polarized ultraviolet radiation, ion beam or plasma beam irradiation at a predetermined angle, and irradiation with radiation may be used. It is preferable to irradiate polarized ultraviolet rays, for example.

The liquid crystal coating layer may be formed by applying a composition for forming a liquid crystal coating layer containing a reactive liquid crystal monomer (RM) or the like commonly used in the art on an alignment film and crosslinking.

Representative examples of the reactive liquid crystal monomer include a cinnamate monofunctional monomer, a phenylbenzoate monofunctional monomer, and a phenylbenzoate based bifunctional monomer. When the reactive liquid crystal monomer is one of these monomers, the bonding force between the polarizer and the patterned retardation layer is particularly excellent when the adhesive composition of the present invention is used.

Preferably, when the reactive liquid crystal monomer is a phenyl benzoate monomer, it is bonded to an adhesive composition containing a monomer of the formula (1), and when the reactive liquid crystal monomer is a cinnamate monomer, it may be bonded to an adhesive composition containing a monomer of the formula . When the reactive liquid crystal monomer contains a phenylbenzoate-based and a cinnamate-based monomer at the same time, it can be bonded with an adhesive composition containing the compounds represented by the general formulas (1) and (2) at the same mixing ratio. In such a case, the effect of improving the bonding force can be maximized.

Specific examples of cinnamate-based monofunctional monomers include monomers of the following general formulas 7-a and 7-b:

[Formula 7-a]

[Formula 7-b]

.

.

Specific examples of the phenylbenzoate-based monofunctional monomer include monomers of the following general formulas 8-a to 8-c:

[Formula 8-a]

[Formula 8-b]

[Formula 8-c]

.

.

Specific examples of the phenylbenzoate-based bifunctional monomers include monomers of the following general formulas 9-a to 9-d:

[Chemical Formula 9-a]

[Formula 9-b]

[Chemical Formula 9-c]

[Chemical Formula 9-d]

.

.

In the case where the patterned retardation layer does not include an alignment film, a composition for forming a liquid crystal coating layer may be applied on a substrate without an alignment film, and the alignment and patterning may be simultaneously performed to form a patterned retardation layer.

In this case, the composition for forming a liquid crystal coating layer may further contain a compound capable of alignment by polarized ultraviolet light such as a linear photopolymerizable polymer for orientation.

When the patterned retardation layer does not include an alignment film, a thinner display can be realized.

<Image Display Device>

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

The image display device is not particularly limited and includes, for example, a stereoscopic image implementing or semi-transmission type liquid crystal display device, a plasma display device, and an organic EL display device.

The complex polarizing plate of the present invention can be used at a position where a conventional polarizing plate and a patterned retardation layer are laminated.

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.

Example  And Comparative Example

An adhesive composition having the compositions and contents shown in Table 1 below was prepared.

division Photopolymerizable compound
(A) Photoinitiator
(B) Multifunctional
Acrylic monomer
(C) ingredient Weight portion ingredient Weight portion Weight portion Example 1 A-1 100 B-1 One - Example 2 A-2 100 B-2 One - Example 3 A-3 100 B-3 One - Example 4 A-4 100 B-4 One - Example 5 A-1 100 B-1 One One Example 6 A-2 100 B-1 One One Example 7 A-1
/ A-3 50
/ 50 B-1 One - Example 8 A-2
/ A-4 50
/ 50 B-1 One - Example 9 A-1
/ A-5 50
/ 50 B-1 One - Example 10 A-3
/ A-6 50
/ 50 B-1 One - Example 11 A-2
/ A-5 50
/ 50 B-1 One - Example 12 A-1
/ A-5 20
/ 80 B-1 One - Comparative Example 1 A-5 100 B-1 One - Comparative Example 2 A-7 100 B-1 One - Comparative Example 3 A-8 100 B-1 One - Comparative Example 4 A-5
/ A-7 (50)
/ (50) B-1 One -

A-2:

A-3:

A-4:

A-5:

A-6:

A-7:

A-8:

B-1: D-1173, 시바사
B-2: I-369, 시바사
B-3: I-907, 시바사
B-4: I-819, 시바사
C: 펜타에리트리톨트리아크릴레이트, 알드리치사A-1:

A-2:

A-3:

A-4:

A-5:

A-6:

A-7:

A-8:

B-1: D-1173,
B-2: I-369,
B-3: I-907,
B-4: I-819,
C: pentaerythritol triacrylate, Aldrich Co.

Experimental Example

(One) Peel force  Measure

A polyvinyl alcohol polarizer having a patterned retardation layer and a triacetyl cellulose protective film bonded on one side was bonded to the adhesive composition of Examples and Comparative Examples using a roll laminator so that the liquid crystal coating layer and the polarizer were in contact with each other. For the evaluation, the end portion was made so that the adhesive was not applied.

Examples 1, 3, 5, 7, 9, 10, and 12 were prepared by coating a triacetyl cellulose film with a solution containing a phenylbenzoate-based reactive liquid crystal monomer represented by Formula 8-b and an initiator as a patterned retardation layer, Cured films were used. Examples 2, 4, 6, 8, and 11 were prepared by coating a solution containing a cinnamate-based reactive liquid crystal monomer (7-b) and an initiator as a patterned retardation layer on a triacetylcellulose film, A dried and cured film was used.

[Formula 7-b]

[Formula 8-b]

.

.

In the comparative example, the same patterned retardation layer as in Example 1 was used.

Thereafter, the adhesive composition was cured by irradiating UV at a wavelength of 313 nm at a light quantity of 2000 mJ / cm ² using a UV exposure machine (Fusion).

The peeling force was measured by cutting the prepared composite polarizing plate sample to a width of 25 mm and peeling at a rate of 300 mm / min in a 180 degree peeling direction.

(2) heat resistance, Humidity Durability  evaluation

A composite polarizing plate was prepared in the same manner as in Experimental Example (1), and an acrylic pressure-sensitive adhesive was applied and cured on the protective film, and then bonded to soda glass and autoclaved.

Then, the heat resistance and the heat and humidity resistance of each of the composite polarizers were tested.

The heat resistance test was carried out at 80 ° C for 500 hours and the humidity and humidity test was conducted at 60 ° C and 90% RH for 500 hours. After that, bubbles or peeling occurred on the bonding surface between the liquid crystal coating layer and the polarizer, And the resistance to humidity was evaluated.

◎: No bubbles or peeling at all

○: There are bubbles or peeling, but only in very small areas.

Δ: Bubbles or peeling were confirmed somewhat

X: Bubbles or exfoliation can easily be visually observed over a significant area

division Peel force (N / 25mm) Heat resistance Humidity Durability Example 1 2.7 ○ ◎ Example 2 3.5 ◎ ◎ Example 3 3.2 ◎ ◎ Example 4 2.9 ◎ ◎ Example 5 2.8 ◎ ◎ Example 6 3.6 ◎ ◎ Example 7 3.5 ◎ ◎ Example 8 3.1 ○ ◎ Example 9 3.9 ◎ ◎ Example 10 4.2 ◎ ◎ Example 11 3.8 ◎ ◎ Example 12 2.3 ○ ◎ Comparative Example 1 0.6 X X Comparative Example 2 1.2 △ △ Comparative Example 3 1.3 △ △ Comparative Example 4 1.9 △ ○

Referring to Table 2, it was confirmed that the composite polarizing plate prepared from the adhesive compositions of Examples 1 to 12 had excellent peel strength, excellent heat resistance and heat and humidity resistance, and excellent durability.

However, it was confirmed that the composite polarizing plate produced from the adhesive compositions of Comparative Examples 1 to 4 was remarkably deteriorated in peel strength, and a large number of bubbles and peeling occurred in evaluation of heat resistance and resistance to heat and humidity, resulting in remarkably low durability.

Claims (10)

Is used for bonding a polarizer and a patterned retardation layer,
An adhesive composition comprising a photopolymerizable compound containing at least one monomer of the following formulas (1) and (2) and a photopolymerization initiator:
[Chemical Formula 1]

(Wherein,
X is a radical reactive functional group;
R ₁ is a direct bond or an alkyl group having 2 to 12 carbon atoms which is substituted or unsubstituted with a hydroxy group, the alkyl group may be interrupted by an oxygen atom;
R ₂ and R ₃ independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, -OR ₄ , -NR ₅ R ₆ or -SR ₇ ;
R ₄ to R ₇ independently represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms or an aryl group having 6 to 18 carbon atoms)
(2)

(Wherein,
R ₁ is a hydrogen atom, a hydroxy group, an alkyl group having 1 to 12 carbon atoms, OR ₄ , or an aryl group having 6 to 18 carbon atoms, wherein the aryl group may be substituted with an acryloxy group;
R ₄ is an acrylic alkyl group or an acrylic oxyalkyl group having 1 to 12 carbon atoms of an alkyl group substituted or unsubstituted with a hydroxyl group, the alkyl group may be interrupted by an oxygen atom;
R ₂ and R ₃ are independently of each other a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or OR ₅ ;
R ₅ is an alkyl group having 1 to 6 carbon atoms, an acryl group, or an acryloxyalkyl group having 1 to 10 carbon atoms in the alkyl group, wherein the alkyl group and the acryloxyalkyl group may be interrupted by an oxygen atom and may be substituted with a hydroxy group.
The adhesive composition according to claim 1, wherein the monomers of the general formulas (1) and (2) have a total content of 30% by weight or more based on the total weight of the total monomers.
The adhesive composition according to claim 1, further comprising at least one of a hydroxyl group-containing acrylic monomer and a carboxyl group-containing acrylic monomer.
4. The adhesive composition according to claim 3, wherein the total content of the hydroxyl group-containing acrylic monomer and the carboxyl group-containing acrylic monomer is 10 to 70% by weight of the total weight of the total monomers.
Polarizer, and
And a patterned retardation layer bonded to one surface of the polarizer through the adhesive composition of any one of claims 1 to 4.
The composite polarizer according to claim 5, wherein the polarizer is a film in which a protective film or a film having a function of a retardation film is bonded to a surface opposite to a surface bonded with the patterned retardation layer.
[7] The method according to claim 5, wherein the patterned retardation layer comprises a liquid crystal material containing at least one reactive liquid crystal monomer selected from the group consisting of a cinnamate monofunctional monomer, a phenylbenzoate monofunctional monomer and a phenylbenzoate based bifunctional monomer, A composite polarizer comprising a coating layer.
[7] The liquid crystal display element of claim 7, wherein the liquid crystal coating layer of the patterned retardation layer contains a phenyl benzoate monomer,
And a cinnamate-based monomer is bonded to an adhesive composition containing a monomer represented by the general formula (2).
The composite polarizer of claim 5, wherein the patterned retardation layer does not include an alignment film.
6. An image display device comprising the composite polarizing plate of claim 5.