KR20150046995A - Adhesive composition and complexed polarization plate using the same - Google Patents

Abstract

The present invention relates to an adhesive composition, and more specifically, to an adhesive composition which comprises a photopolymerizable compound including a styrene-based monomer having a secondary amino group, and a photopolymerizable initiator, improves graft force between a polarizer and a patterned retardation layer when grafting the polarizer and the patterned retardation layer and manufacturing a composite polarizing plate, improves thermal resistance and moist-heat resistance, and has excellent three-dimensional stereo 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 method for producing a film pattern reliader and a film pattern reliator, and a polarizing plate and an image display device having the film pattern reliator.

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 when used for producing 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 adhesive composition comprising a photopolymerizable compound comprising a styrenic monomer having a secondary amino group and a photopolymerization initiator.

2. The adhesive composition according to 1 above, wherein the styrene-based monomer having a secondary amino group is represented by the following formula (1).

[Chemical Formula 1]

(Wherein R ₁ is a hydrogen atom or a methyl group;

R ₂ is an alkylene group having 1 to 5 carbon atoms which may be interrupted by a nitrogen atom;

R ₃ is an alkyl or benzyl group having 1 to 5 carbon atoms, which may be interrupted by an oxygen atom, substituted or unsubstituted with a hydroxy group or an amino group, or may be connected to R ₂ to form a ring having 4 to 6 carbon atoms.

3. The adhesive composition according to 1 above, wherein the styrene-based monomer having a secondary amino group is contained in an amount of 10% by weight or more based on the total weight of the total monomers.

4. The adhesive composition of claim 1, wherein the photopolymerizable compound further comprises 0 to 5% by weight of a non-polar styrenic monomer in the total weight of the total monomers.

5. The adhesive composition according to 1 above, wherein said photopolymerizable compound further comprises 0 to 85% by weight of styrene monomer having a polar group excluding an amino group in the total weight of all monomers.

6. The adhesive composition according to 1 above, wherein the photopolymerization initiator is a radical photopolymerization initiator comprising at least one selected from the group consisting of acetophenone, benzophenone, thioxanthone, benzoin and benzoin alkyl ether.

7. Polarizer, and

And a patterned retardation layer bonded to one side of the polarizer through an adhesive composition as defined in any one of [1] to [6] above.

8. The composite polarizer of claim 7, wherein the polarizer is formed by bonding a protective film or a film having a function of a retardation film to the opposite surface of the surface to be bonded with the patterned retardation layer.

9. The composite polarizer of claim 7, wherein the patterned retardation layer comprises a liquid crystal coating layer containing a reactive liquid crystal monomer comprising a benzene ring.

10. The composite polarizer according to 7 above, wherein the peeling force between the polarizer and the patterned retardation layer is 2.0 N / 25 mm or more.

11. The composite polarizer of claim 7, wherein the patterned retardation layer does not comprise an alignment film.

12. An image display device comprising the composite polarizing plate of 7 above.

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 includes a photopolymerizable compound containing a styrenic monomer having a secondary amino group and a photopolymerization initiator, so that when a polarizer and a patterned retardation layer are bonded to form a composite polarizing plate, the polarizer and the patterned retardation layer 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 comprises a photopolymerizable compound comprising a styrenic monomer having a secondary amino group.

The adhesive composition of the present invention has excellent bonding strength when used for bonding a polarizer and a patterned retardation layer, and the heat resistance and the resistance to moisture and humidity are also improved by such bonding strength improvement. This is because the styrenic monomer according to the present invention contains an amino group, the amino group is hydrogen bonded to the polar group contained in the liquid crystal coating layer of the polarizer surface polar group and the patterned retardation layer, and the reactive liquid crystal monomer contained on the liquid crystal coating layer To form an amide bond with the ester bond to form a covalent bond.

It is also believed that the pi-bonding interaction between the benzene ring of the styrene-based monomer and the benzene ring contained in the liquid crystal coating layer of the patterned retardation layer will contribute to this.

In the case of a styrenic monomer having a primary amino group, the photopolymerization initiator may react with a ketone functional group of a photopolymerization initiator to form an imine, thereby lowering the photocatalytic effect, thereby lowering the photocuring efficiency.

The styrene-based monomer having a secondary amino group according to the present invention is not particularly limited, and examples thereof include monomers represented by the following formula (1):

[Chemical Formula 1]

(Wherein R ₁ is a hydrogen atom or a methyl group;

R ₂ is an alkylene group having 1 to 5 carbon atoms which may be interrupted by a nitrogen atom;

R ₃ is an alkyl or benzyl group having 1 to 5 carbon atoms, which may be interrupted by an oxygen atom, substituted or unsubstituted with a hydroxy group or an amino group, or may be connected to R ₂ to form a ring having 4 to 6 carbon atoms.

Specific examples of the styrenic monomer having a secondary amino group include the following formulas (a-1) to (a-5), which may be used alone or in combination of two or more.

 [Formula a-1]

[Formula a-2]

[Formula a-3]

[Formula a-4]

[Formula a-5]

The content of the styrenic monomer having a secondary amino group is not particularly limited within a range that can perform the functions described above, and may be, for example, 10 to 100% by weight of the total weight of the total monomers. When the content is within the above range, an excellent bonding force between the polarizer and the patterned retardation layer can be exhibited.

To the extent that the object of the present invention is not adversely affected, the photopolymerizable compound according to the present invention may further comprise a styrenic monomer having no amino group.

Examples of the styrenic monomer having no amino group include a non-polar styrenic monomer and a styrenic monomer having a polar group except an amino group.

The non-polar styrenic monomer improves resistance to humidity and humidity.

The kind of the non-polar styrene-based monomer is not particularly limited, and examples thereof include styrene, vinyl toluene,? -Methyl styrene, dimethyl styrene, t-butyl styrene and the like. These may be used alone or in combination of two or more.

The content of the non-polar styrenic monomer is not particularly limited and may be, for example, 0 to 5% by weight of the total weight of the total monomers. When the content is more than 5% by weight, the heat resistance may be somewhat lowered.

Examples of the styrene monomer having a polar group except for the amino group are not particularly limited and include styrene having a halogen element, a hydroxyl group, a carboxyl group, a sulfonic acid group, a phosphoric acid group, an alkoxy group having 1 to 6 carbon atoms, . These may be used alone or in combination of two or more.

The content of the styrene monomer having a polar group excluding the amino group is not particularly limited and may be, for example, 0 to 85% by weight of the total weight of the total monomers. When the content exceeds 85% by weight, the adhesive strength 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.

<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 forms a hydrogen bond, an amide bond with the patterned retardation layer, and a pi bond interaction can be generated.

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 conventionally used in the art may be used, but it 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.

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 peeling force between the polarizer and the patterned retardation layer may be 2.0 N / 25 mm or more, preferably 3.0 to 5.0 N / 25 mm 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  And Comparative Example

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

division Photopolymerizable compound Photopolymerization initiator
(D) A styrene-based monomer having a secondary amino group
(A) A styrene-based monomer having a polar group except an amino group
(B) Other Monomers
(C) ingredient Weight portion ingredient Weight portion ingredient Weight portion ingredient Weight portion Example 1 A-1 100 - - - - D-1 One Example 2 A-2 100 - - - - D-1 One Example 3 A-3 100 - - - - D-1 One Example 4 A-4 100 - - - - D-1 One Example 5 A-5 100 - - - - D-1 One Example 6 A-1 50 B-1 50 - - D-1 One Example 7 A-1 50 B-2 50 - - D-1 One Example 8 A-1 50 B-3 50 - - D-1 One Example 9 A-1 50 B-1 48 C-1 2 D-1 One Example 10 A-1 50 B-1 48 C-2 2 D-2 One Example 11 A-1 50 B-1 48 C-3 2 D-3 One Example 12 A-1 10 B-1 85 C-1 5 D-1 One Example 13 A-1 8 B-1 87 C-1 5 D-1 One Example 14 A-1 10 B-1 83 C-1 7 D-1 One Comparative Example 1 - - - - C-1 100 D-1 One Comparative Example 2 - - B-1 100 - - D-2 One Comparative Example 3 - - B-1 50 C-1 50 D-2 One Comparative Example 4 - - - - C-4 100 D-1 One Comparative Example 5 - - - - C-5 100 D-1 One

A-2 :

A-3 :

A-4 :

A-5 :

B-1:

B-2:

B-3:

C-1:

C-2:

C-3:

C-4:

C-5:

D-1: Igacure-184 (바스프사)
D-2: Igacure-369 (바스프사) D-3: Igacure-907 (바스프사)A-1:

A-2:

A-3:

A-4:

A-5:

B-1:

B-2:

B-3:

C-1:

C-2:

C-3:

C-4:

C-5:

D-1: Igacure-184 (BASF)
D-2: Igacure-369 (BASF) D-3: Igacure-907 (BASF)

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, 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 coated 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 3.4 ◎ ◎ Example 2 3.5 ◎ ◎ Example 3 3.6 ◎ ◎ Example 4 3.8 ◎ ◎ Example 5 2.5 ○ ○ Example 6 3.2 ○ ○ Example 7 3.1 ○ ○ Example 8 3.0 ○ ○ Example 9 3.1 ○ ◎ Example 10 3.0 ○ ◎ Example 11 2.9 ○ ◎ Example 12 2.6 ○ ◎ Example 13 2.1 △ ○ Example 14 2.5 △ ◎ Comparative Example 1 0.2 X X Comparative Example 2 1.2 X △ Comparative Example 3 0.8 X △ Comparative Example 4 0.8 X X Comparative Example 5 0.7 X X

Referring to Table 2, it was confirmed that the composite polarizing plates of Examples 1 to 14 had a very high peeling force, excellent heat resistance and heat and humidity resistance, and excellent durability.

However, in the composite polarizing plates of Comparative Examples 1 to 5, the peeling force was remarkably decreased, and a large number of bubbles and peeling occurred in evaluation of heat resistance and resistance to heat and humidity, and durability was remarkably low.

Claims (12)

A photopolymerizable compound comprising a styrenic monomer having a secondary amino group, and a photopolymerization initiator.
The adhesive composition according to claim 1, wherein the styrene-based monomer having a secondary amino group is represented by the following formula (1).
[Chemical Formula 1]

(Wherein R ₁ is a hydrogen atom or a methyl group;
R ₂ is an alkylene group having 1 to 5 carbon atoms which may be interrupted by a nitrogen atom;
R ₃ is an alkyl or benzyl group having 1 to 5 carbon atoms, which may be interrupted by an oxygen atom, substituted or unsubstituted with a hydroxy group or an amino group, or may be connected to R ₂ to form a ring having 4 to 6 carbon atoms.
The adhesive composition according to claim 1, wherein the styrene-based monomer having a secondary amino group is contained in an amount of 10% by weight or more based on the total weight of the total monomers.
2. The adhesive composition of claim 1, wherein the photopolymerizable compound further comprises from 0 to 5% by weight of the total weight of the total monomers of the non-polar styrenic monomer.
The adhesive composition according to claim 1, wherein the photopolymerizable compound further comprises 0 to 85% by weight of styrene monomer having a polar group excluding an amino group in a total weight of all monomers.
The adhesive composition according to claim 1, wherein the photopolymerization initiator is a radical photopolymerization initiator comprising at least one selected from the group consisting of acetophenone, benzophenone, thioxanthone, benzoin and benzoin alkyl ethers.
Polarizer, and
And a patterned retardation layer bonded to one side of the polarizer through the adhesive composition of any one of claims 1 to 6. A polarizing plate comprising:
The composite polarizer according to claim 7, 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 to the patterned retardation layer.
The composite polarizer of claim 7, wherein the patterned retardation layer comprises a liquid crystal coating layer containing a reactive liquid crystal monomer comprising a benzene ring.
The composite polarizer according to claim 7, wherein the peeling force between the polarizer and the patterned retardation layer is 2.0 N / 25 mm or more.
The composite polarizer of claim 7, wherein the patterned retardation layer does not comprise an alignment layer.
8. An image display apparatus comprising the composite polarizing plate of claim 7.