KR101902907B1 - Adhesive composition and complexed polarization plate using the same - Google Patents

Abstract

More particularly, the present invention relates to an acrylic copolymer containing a copolymer of an acrylic monomer having a hydroxyl group or a carboxyl group and an acrylic monomer having an aromatic ring having a carbon number of 6 to 18; And a crosslinking agent, it is possible to remarkably improve the bonding force between the polarizer and the patterned retardation layer, to improve the heat resistance and the heat and humidity resistance when the polarizer and the patterned retardation layer are used to produce a composite polarizing plate, To an adhesive composition for facilitating bonding to a display panel or the like when applied to a display device, and a composite polarizer using the adhesive composition.

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

It is an object of the present invention to provide an adhesive composition capable of remarkably improving the bonding force between a polarizer and a patterned retardation layer when used to manufacture a composite polarizing plate by bonding 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. An acrylic copolymer containing a copolymer of an acrylic monomer having a hydroxyl group or a carboxyl group and an acrylic monomer having an aromatic ring having a carbon number of 6 to 18; And a crosslinking agent.

2. The acrylic pressure-sensitive adhesive composition according to 1 above, wherein the acrylic monomer having a hydroxy group is selected from the group consisting of hydroxyethyl acrylate, hydroxybutyl acrylate, (4- (hydroxymethyl) cyclohexyl) methyl acrylate and hydroxyethyl acrylamide Lt; RTI ID = 0.0 > 1, < / RTI >

3. The acrylic polymer composition according to item 1, wherein the acrylic monomer having a carboxyl group is (meth) acrylic acid, carboxyethyl (meth) acrylate and 4- (2- (acryloyloxy) ethoxy) Lt; RTI ID = 0.0 > 1, < / RTI >

4. The photosensitive resin composition according to item 1, wherein the acrylic monomer having an aromatic ring having 6 to 18 carbon atoms is 2-hydroxy-3-phenoxypropyl acrylate, 4- (2- (acryloyloxy) ethoxy) ) Benzoic acid, 2-hydroxy-3- (phenylamino) propyl acrylate, and 2 - ((2-acrylamidoethoxy) carbonyl) benzoic acid.

5. The adhesive composition according to item 1, wherein the acrylic monomer having an aromatic ring having 6 to 18 carbon atoms is contained and polymerized at a weight ratio of 1: 9 to 5: 5, based on the acrylic monomer having a hydroxyl group and the acrylic monomer having a carboxyl group.

6. The adhesive composition according to 1 above, wherein the acrylic copolymer is further polymerized by containing an ionic monomer.

7. The adhesive composition according to the above 6, wherein the ionic monomer is an acryl-based ammonium salt, a vinyl imidazole-based ammonium salt or a mixture thereof.

8. The adhesive composition according to 6 above, wherein the ionic monomer is polymerized in an amount of from 10 to 50% by weight of the total monomers.

9. The composition of claim 1 wherein said crosslinking agent is selected from the group consisting of monoaldehydes, dialdehydes, amino-formaldehyde resins, glyoxalates, acetal compounds, divalent metals, trivalent metals, tetravalent metals, metal chelating compounds, oxazolines Wherein the adhesive composition is at least one selected from the group consisting of melamine, melamine, aziridines, and polyfunctional inorganic acids.

10. The adhesive composition according to 1 above, wherein the cross-linking agent is contained in an amount of 0.5 to 20 parts by weight based on 100 parts by weight of the acrylic copolymer based on the solid content.

11. A composite polarizer comprising a polarizer and a patterned retardation layer bonded to one side of the polarizer through an adhesive composition of any one of claims 1 to 10 above.

12. The composite polarizer of claim 11, 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.

13. The composite polarizer of claim 11, wherein the patterned retardation layer comprises a liquid crystal coating layer containing a reactive liquid crystal monomer containing a benzene ring.

14. The composite polarizing plate as in 11 above, wherein the patterned retardation layer does not include an alignment film.

15. The composite polarizer of claim 11, wherein the corner portion is bent toward the patterned retardation layer side from the polarizer side.

16. The composite polarizer of claim 15, wherein the difference in elevation from the peak center of the polarizer to the highest point of 5 cm from the center of gravity and the center of gravity is at least 3 mm.

17. The composite polarizer of claim 11, wherein the peel strength between the polarizer and the patterned retardation layer is greater than or equal to 2N / 25 mm.

18. An image display device comprising the composite polarizing plate of the above 11.

The adhesive composition of the present invention significantly improves the bonding force between the polarizer and the patterned retardation layer when used to produce a composite polarizer plate by bonding a polarizer and a patterned retardation layer.

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

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

The composite polarizing plate bonded with the adhesive composition of the present invention can be easily bonded to a display panel or the like when applied to an image display device.

Fig. 1 shows the state of the composite polarizer bonded with the adhesive composition of the present invention immediately after bonding and the state of warpage due to moisture absorption.

The present invention relates to an acrylic copolymer containing a copolymer of an acrylic monomer having a hydroxyl group or a carboxyl group and an acrylic monomer having an aromatic ring having a carbon number of 6 to 18; And a crosslinking agent, it is possible to remarkably improve the bonding force between the polarizer and the patterned retardation layer, to improve the heat resistance and the heat and humidity resistance when the polarizer and the patterned retardation layer are used to produce a composite polarizing plate, To an adhesive composition for facilitating bonding to a display panel or the like when applied to a display device, and a composite polarizer using the adhesive composition.

Hereinafter, the present invention will be described in detail.

≪ Adhesive composition >

The adhesive composition of the present invention includes an acrylic copolymer as an aqueous adhesive.

The acrylic copolymer according to the present invention is a copolymer of an acrylic monomer having a hydroxyl group or a carboxyl group and an acrylic monomer having an aromatic ring having 6 to 18 carbon atoms.

Specifically, a copolymer of an acrylic monomer having a hydroxy group / an acrylic monomer having an aromatic ring having 6 to 18 carbon atoms, an acrylic monomer having a carboxyl group / an acrylic monomer having an aromatic ring having a carbon number of 6 to 18, or an acrylic monomer having a hydroxy group An acrylic monomer having a monomer / carboxyl group / an acrylic monomer having an aromatic ring having 6 to 18 carbon atoms.

The acrylic monomer having a hydroxyl group or a carboxyl group significantly improves the bonding force between the polarizer and the patterned retardation layer when the adhesive composition of the present invention is used for producing a composite polarizer plate by bonding the polarizer and the patterned retardation layer. It is judged that this is due to hydrogen bonding with the polar group surface polar group and the polar group contained in the liquid crystal coating layer of the patterned retardation layer.

Likewise, the acrylic monomer having an aromatic ring remarkably improves the bonding force between the polarizer and the patterned retardation layer, which is judged to be due to the pi-bonding interaction with the benzene ring contained in the liquid crystal coating layer of the patterned retardation layer. The improvement of the bonding strength also improves the heat resistance and the heat and humidity resistance.

The acrylic monomer having a hydroxy group is not particularly limited and monomers commonly used in the art can be used, but those having a high solubility in solvents are preferred, and examples thereof include hydroxyethyl acrylate, hydroxybutyl acrylate, (4- (Hydroxymethyl) cyclohexyl) methyl acrylate, and hydroxyethyl acrylamide. These may be used alone or in combination of two or more.

The acrylic monomer having a carboxyl group is not particularly limited, and monomers commonly used in the art can be used, but it is preferable that the monomer has high solubility in a solvent. Examples thereof include (meth) acrylic acid, carboxyethyl (meth) (2- (acryloyloxy) ethoxy) -4-oxobutanoic acid, and the like. These may be used alone or in combination of two or more.

The acrylic monomer having an aromatic ring having 6 to 18 carbon atoms is not particularly limited and monomers commonly used in the art may be used, but those having a high solubility are preferable for improving water dispersibility. Further, it may further include a hydroxy group or a carboxyl group in terms of improving the bonding force between the polarizer and the patterned retardation layer. For example, there may be mentioned 2-hydroxy-3-phenoxypropyl acrylate, 4 - ((2- (acryloyloxy) ethoxy) carbonyl) benzoic acid, 2- Acrylate, 2 - ((2-acrylamidoethoxy) carbonyl) benzoic acid, and the like. These may be used alone or in combination of two or more.

The mixing ratio of the acrylic monomer having a hydroxyl group or a carboxyl group and the acrylic monomer having an aromatic ring having a carbon number of 6 to 18 is not particularly limited within a range that can perform the functions described above. For example, an acrylic monomer having an aromatic ring having 6 to 18 carbon atoms The acrylic monomer may be polymerized in an amount of 1: 9 to 5: 5 by weight based on the weight of the acrylic monomer having a hydroxyl group and the acrylic monomer having a carboxyl group. When the mixing ratio is within the above range, the bonding force between the polarizer and the patterned retardation layer can be maximized.

If necessary, the acrylic copolymer according to the present invention can be polymerized by further containing an ionic monomer. In such a case, the solubility in the solvent is remarkably improved, and the occurrence of poor viscous property caused by the residual foreign matter can be suppressed.

The ionic monomer according to the present invention is not particularly limited as long as it has the above-mentioned effect of solubility improvement, and examples thereof include acrylic ammonium salt and vinyl imidazole ammonium salt. Specifically, monomers represented by the following general formulas (1) to (3) are exemplified. These may be used alone or in combination of two or more.

[Chemical Formula 1]

(2)

(3)

The content of the ionic monomer is not particularly limited within the range capable of performing the function, and may be, for example, 10 to 50% by weight of the total monomer. When the content is within the above range, excellent solubility and adhesive strength can be satisfied at the same time.

The molecular weight of the acrylic copolymer is not particularly limited, and for example, the weight average molecular weight may be 5,000 to 100,000.

The acrylic copolymer may be prepared by a conventional polymerization method, and the weight average molecular weight may be controlled by changing conditions such as the content of the initiator, the reaction temperature, the reaction time, the kind and content of the catalyst, and the use of other components. The kind of the solvent and the polymerization initiator is not particularly limited, and those known in the art can be used.

If necessary, the adhesive composition of the present invention may further comprise a copolymer such as polyvinyl alcohol, polyamine and the like commonly used in the art in addition to the acrylic copolymer.

The adhesive composition of the present invention further comprises a crosslinking agent.

The cross-linking agent is not particularly limited, and a cross-linking agent commonly used in the art can be used. Examples of the aldehyde include monoaldehydes such as formaldehyde, acetaldehyde, propionaldehyde and butylaldehyde; dialdehydes such as glyoxal, malondialdehyde, succindialdehyde, glutarialdehyde, maleindialdehyde and phthalaldehyde; An amino-formaldehyde resin such as methylol urea, methylol melamine, alkylated methylol urea, alkylated methylol melamine, acetoguanamine, condensates of benzoguanamine and formaldehyde; glyoxylic acid metal salts For example, alkali metals such as lithium, sodium and potassium, alkaline earth metals such as magnesium and calcium, transition metals such as titanium, zirconium, chromium, manganese, iron, cobalt, nickel and copper, zinc and aluminum) Glyoxylic acid salts such as glyoxylic acid amine salts (examples of the amine include ammonia, monomethylamine, dimethylamine, trimethylamine and the like); Divalent metals such as magnesium, calcium, aluminum, iron, nickel; methoxy bullet, bullet-diethoxy, acetal compounds of the bullet, such as a dialkoxy on; A trivalent metal; A tetravalent metal; Metal chelating compounds; Oxazolines; Melamine; Aziridines; And polyvalent inorganic acids such as boric acid, phosphoric acid, and sulfuric acid. These may be used alone or in combination of two or more.

The content of the crosslinking agent is not particularly limited and may be, for example, 0.5 to 20 parts by weight based on 100 parts by weight of the acrylic copolymer based on the solid content. When the content of the crosslinking agent is within the above range, the effect of improving the bonding force between the polarizer and the patterned retardation layer is excellent.

<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. In this case, as described above, the adhesive composition layer forms a hydrogen bond with the polarizer and can form a pi-bonding interaction with the patterned retardation layer.

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 or a film having a function of a retardation film may be bonded to a surface opposite to 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.

The reactive liquid crystal monomer is not particularly limited, and monomers commonly used in the art can be used, but may preferably be a monomer having a benzene ring.

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.

In general, the polarizing plate is attached to a display panel or the like and applied to an image display apparatus, and this conjugation can easily be performed in the composite polarizing plate of the present invention.

Specifically, the bonding with the water-based adhesive is carried out including a coating step, a bonding step and a drying step. Since the polarizer and the protective film are highly hygroscopic, they absorb moisture and expand after the drying step. In such a case, as shown in Fig. 1, the edge portion of the composite polarizing plate is bent toward the patterned retardation layer side from the polarizer side, so that easy joining is possible.

The degree of fin is not particularly limited as long as it can be easily joined and is not limited to the durability, for example, the difference between the center of gravity of the polarizer and the highest point of 5 cm from the center of gravity may be 3 mm or more. When the degree of fin is within the above range, easiness of joining can be maximized. It may preferably be 3 to 5 mm in that it has excellent physical properties and bonding properties.

The composite polarizing plate of the present invention prepared using the above adhesive composition has excellent bonding strength between the polarizer and the patterned retardation layer. For example, the peel force between the polarizer and the patterned retardation layer may be 2N / 25mm or more, preferably 3 to 5N / 25mm or more.

<Image Display Device>

Further, the present invention provides an image display apparatus including the composite polarizer.

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  One

100 parts by weight of an acrylic copolymer having a weight ratio of hydroxyethyl acrylate, carboxyethyl acrylate and 2-hydroxy-3-phenoxypropyl acrylate of 4: 4: 2 and a weight average molecular weight of 10,000, based on the solid content, And 3 parts by weight of zinc chloride as a crosslinking agent were mixed and diluted with distilled water to a concentration of 3% to prepare an adhesive composition.

Example  2

Based on the solids content, the weight ratio of hydroxyethyl acrylate, 4- (2- (acryloyloxy) ethoxy) -4-oxobutanoic acid and 2-hydroxy-3-phenoxypropyl acrylate is 4: 4: 2, 100 parts by weight of an acrylic copolymer having a weight average molecular weight of 10,000, and 3 parts by weight of zinc chloride as a crosslinking agent were mixed and diluted with distilled water to a concentration of 2% to prepare an adhesive composition.

Example  3

Based on the solids content, the weight ratio of hydroxyethyl acrylamide, 4- (2- (acryloyloxy) ethoxy) -4-oxobutanoic acid and 2-hydroxy-3-phenoxypropyl acrylate is 2: 100 parts by weight of an acrylic copolymer having a weight average molecular weight of 10,000 and 6: 2, and 3 parts by weight of zinc chloride as a crosslinking agent were mixed and diluted with distilled water to a concentration of 2% to prepare an adhesive composition.

Example  4

(Acryloyloxy) ethoxy) -4-oxobutanoic acid and 2 - ((2-acrylamidoethoxy) carbonyl) benzoic acid, based on the solids content, 100 parts by weight of an acrylic copolymer having a weight ratio of 4: 4: 2 and a weight average molecular weight of 10,000, and 3 parts by weight of zinc chloride as a crosslinking agent were mixed and diluted with distilled water to a concentration of 2% to prepare an adhesive composition.

Example  5

Wherein the weight ratio of hydroxyethyl acrylate, acrylic acid, 2-hydroxy-3-phenoxypropyl acrylate and monomers of formula 1 is 2: 2: 3: 3 and the weight average molecular weight is 10,000, based on the solid content, 100 parts by weight of a copolymer and 3 parts by weight of zinc chloride as a crosslinking agent were mixed and diluted with distilled water to a concentration of 2% to prepare an adhesive composition.

 [Chemical Formula 1]

Example  6

Based on the solids content, a weight ratio of hydroxyethyl acrylate, carboxyethyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate and monomers of the formula 3: 2: 2: 3: 3, 100 parts by weight of an acrylic copolymer and 3 parts by weight of zinc chloride as a crosslinking agent were mixed and diluted with distilled water to a concentration of 2% to prepare an adhesive composition.

(3)

Example  7

The adhesive composition was prepared in the same manner as in Example 1, except that the weight ratio of hydroxyethyl acrylate, carboxyethyl acrylate and 2-hydroxy-3-phenoxypropyl acrylate was 50: 45: 5 based on the solid content. .

Example  8

Based on the solids content, the weight ratio of hydroxyethyl acrylate, 4- (2- (acryloyloxy) ethoxy) -4-oxobutanoic acid and 2-hydroxy-3-phenoxypropyl acrylate is 20: 25: 55. The adhesive composition was prepared in the same manner as in Example 2.

Example  9

Was the same as in Example 5 except that the weight ratio of hydroxyethyl acrylate, acrylic acid, 2-hydroxy-3-phenoxypropyl acrylate and monomer of formula (1) was 30: 30: 35: 5, To prepare an adhesive composition.

Example  10

Except that the weight ratio of the hydroxyethyl acrylate, carboxyethyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate and the monomer of formula 3 was 10: 20: 15: 55, based on the solids content, The adhesive composition was prepared in the same manner as in Example 6.

Example  11

The adhesive composition was prepared in the same manner as in Example 1 except that the crosslinking agent content was 22 parts by weight.

Comparative Example  One

100 parts by weight of a 2-phenoxy-ethylacrylate homopolymer having a weight average molecular weight of 10,000 and 3 parts by weight of zinc chloride as a crosslinking agent were mixed in a mixed solvent of distilled water and acetone (volume ratio 50: 50) to prepare an adhesive composition.

Comparative Example  2

An adhesive composition was prepared in the same manner as in Example 1, except that an acrylic copolymer having a weight ratio of hydroxyethyl acrylate and carboxyethyl acrylate of 4: 6 and a weight average molecular weight of 10,000 was used based on the solid content. Respectively.

Comparative Example  3

1 part by weight of Igacure-184 (BASF Corp.) as an initiator was added to 100 parts by weight of 2-hydroxy-3-phenoxypropyl acrylate to prepare a photopolymerizable adhesive composition.

Experimental Example

(One) Peel force  Measure

A polyvinyl alcohol polarizer in which a patterned retardation layer (MPR32, DNP yarn) and a triacetyl cellulose protective film were bonded to one side was made to contact the liquid crystal coating layer and the polarizer, and the adhesive compositions of Examples and Comparative Examples were laminated using a roll laminator Respectively. For the evaluation, the end portion was not coated with the adhesive.

Thereafter, it was dried at 100 DEG C for 3 minutes and allowed to stand at room temperature for 48 hours to be cured.

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.

Thereafter, each of the substrates was allowed to stand at 80 ° C for 500 hours, 60 ° C, and 90% RH for 500 hours. Then, bubbles or peeling occurred on the bonding surface between the liquid crystal coating layer and the polarizer were examined. Respectively.

○ : No bubbles or peeling

Δ : Bubbles or peeling were observed, but only in very small areas.

X: Bubbles or peeling can be easily confirmed with the naked eye

In the case of ○, the evaluation was made only when both the heat resistance and the heat and humidity resistance were in accordance with the above criteria. Δ and X were evaluated as Δ or X even when only one of the heat resistance and the heat and humidity resistance was in accordance with the above criteria.

(3) Measurement of bending degree

The center of gravity of the composite polarizer prepared in the same manner as in Experimental Example (1) was cut to 10 cm x 10 cm and the patterned retardation layer was laid up on a flat work surface.

Then, the height from the workbench to the center of the side with the highest height on the side of the polarizer was measured.

division Peel force (N / 25mm) Heat resistance, heat resistance Degree of bending (mm) Example 1 3.7 ○ 3.8 Example 2 3.5 ○ 4.0 Example 3 3.5 ○ 3.8 Example 4 3.3 ○ 3.5 Example 5 4.3 ○ 3.9 Example 6 4.9 ○ 4.2 Example 7 2.5 ○ 3.2 Example 8 2.9 ○ 3.0 Example 9 3.9 ○ 3.6 Example 10 3.7 ○ 3.5 Example 11 2.2 ○ 3.1 Comparative Example 1 0.8 X 2.5 Comparative Example 2 1.0 X 2.8 Comparative Example 3 1.4 ○ 0

Referring to Table 1, the composite polarizing plates bonded with the adhesive compositions of Examples 1 to 4 were excellent in peel strength of 3.3 N / 25 mm or more and had neither bubbles nor peeling at all, . Then, it was confirmed that it is possible to easily join by warping more than 3.5 mm.

In the case of the adhesive compositions of Examples 5 and 6, the peeling force of the composite polarizing plate including the acrylic copolymer polymerized with the ionic monomer was even better.

The adhesive compositions of Examples 7 and 8 showed a somewhat lowered performance because the content ratio of the acrylic monomer was out of the preferable range, but still showed excellent performance.

In the case of the adhesive compositions of Examples 9 and 10, the ionic monomer content deviates from the preferred range to slightly lower the performance as compared with Examples 5 and 6, but still shows excellent performance.

The performance of Example 11 including an excessive amount of a crosslinking agent was somewhat lowered, but still excellent performance was shown.

However, in the case of Comparative Examples 1 to 3, the peeling force was significantly lowered. In addition, in the case of Comparative Examples 1 and 2, the heat resistance and the heat and humidity resistance were poor. In Comparative Example 3, it was confirmed that bonding was not easy because it was not warped at all.

100: Polarizer 200: Adhesive layer
300: patterned retardation layer 400: protective film

Claims (18)

An acrylic copolymer containing a copolymer of an acrylic monomer having a hydroxyl group or a carboxyl group, an acrylic monomer having an aromatic ring having 6 to 18 carbon atoms, and an ionic monomer; And
And a crosslinking agent.
The acrylic pressure-sensitive adhesive composition according to claim 1, wherein the acrylic monomer having a hydroxyl group is selected from the group consisting of hydroxyethyl acrylate, hydroxybutyl acrylate, (4- (hydroxymethyl) cyclohexyl) methyl acrylate and hydroxyethyl acrylamide At least one adhesive composition.
[2] The method according to claim 1, wherein the acrylic monomer having a carboxyl group is at least one selected from the group consisting of (meth) acrylic acid, carboxyethyl (meth) acrylate and 4- (2- (acryloyloxy) ethoxy) Lt; RTI ID = 0.0 &gt; 1, &lt; / RTI &gt;
The acrylic copolymer according to claim 1, wherein the acrylic monomer having an aromatic ring having 6 to 18 carbon atoms is at least one selected from the group consisting of 2-hydroxy-3-phenoxypropyl acrylate, 4- (2- (acryloyloxy) ethoxy) Wherein the adhesive composition is at least one selected from the group consisting of acrylic acid, 2-hydroxy-3- (phenylamino) propyl acrylate, and 2 - ((2-acrylamidoethoxy) carbonyl) benzoic acid.
The adhesive composition according to claim 1, wherein the acrylic monomer having an aromatic ring having 6 to 18 carbon atoms is contained and polymerized in a weight ratio of 1: 9 to 5: 5 with respect to the acrylic monomer having a hydroxyl group and the acrylic monomer having a carboxyl group.
delete The adhesive composition according to claim 1, wherein the ionic monomer is an acryl-based ammonium salt, a vinyl imidazole-based ammonium salt or a mixture thereof.
The adhesive composition according to claim 1, wherein the ionic monomer is polymerized in an amount of 10 to 50% by weight of the total monomer.
[3] The method of claim 1, wherein the crosslinking agent is selected from the group consisting of monoaldehydes, dialdehydes, amino-formaldehyde resins, glyoxalates, acetal compounds, divalent metals, trivalent metals, tetravalent metals, metal chelating compounds, At least one selected from the group consisting of melamine, aziridines, and polyfunctional inorganic acids.
The adhesive composition according to claim 1, wherein the crosslinking agent is contained in an amount of 0.5 to 20 parts by weight based on 100 parts by weight of the acrylic copolymer based on the solid content.
Polarizer, and
Wherein the polarizer comprises a patterned retardation layer bonded to one side of the polarizer through the adhesive composition of any one of claims 1 to 5 and claims 7 to 10.
12. The polarizing plate of claim 11, 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 with the patterned retardation layer.
12. The composite polarizer of claim 11, wherein the patterned retardation layer comprises a liquid crystal coating layer containing a reactive liquid crystal monomer comprising a benzene ring.
12. The composite polarizer of claim 11, wherein the patterned retardation layer does not comprise an alignment film.
12. The composite polarizer of claim 11, wherein the edge portion is bent toward the patterned retardation layer side from the polarizer side.
16. The composite polarizer of claim 15, wherein the height difference between the center of gravity of the polarizer and the highest point of 5 cm from the center of gravity is 3 mm or more.
The composite polarizer according to claim 11, wherein the peeling force between the polarizer and the patterned retardation layer is 2 N / 25 mm or more.
An image display device comprising the composite polarizing plate of claim 11.

Images