KR101938412B1 - Adhesive composition and complexed polarization plate using the same - Google Patents

Abstract

The present invention relates to an adhesive composition and a composite polarizing plate using the same, and more particularly to a polarizing plate comprising a water-soluble resin and a cross-linking agent interposed between a polarizer and a patterned retardation layer and comprising a polyamine resin having a primary or secondary amino group An adhesive composition which improves bonding strength between a polarizer and a patterned retardation layer, improves heat resistance and heat and humidity resistance, as well as facilitates bonding to a display panel or the like when applied to an image display apparatus, 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

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. An adhesive composition comprising a water-soluble resin and a crosslinking agent, the water-soluble resin comprising a polyamine resin having a primary or secondary amino group and a cross-linking agent, the cross-linking agent being used for bonding a polarizer and a patterned retardation layer.

2. The adhesive composition of 1 above, wherein the patterned retardation layer comprises a liquid crystal coating layer formed on the side in contact with the polarizer.

3. The adhesive composition of 2 above, wherein the liquid crystal coating layer is formed from a composition for forming a liquid crystal coating layer comprising a monomer having a benzene ring and an ester bond.

4. The adhesive composition according to 1 above, wherein the polyamine resin is at least one selected from the group consisting of an allylamine polymer, a diallylamine polymer and a vinylamine polymer.

5. The adhesive composition according to 1 above, wherein the polyamine resin is contained in an amount of 10% by weight or more based on the total weight of the water-soluble resin.

6. 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 chelate compounds, oxazolines Wherein the adhesive composition is at least one selected from the group consisting of melamine, melamine, aziridines, and polyfunctional inorganic acids.

7. 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 solid-based water-soluble resin.

8. A composite polarizer comprising a polarizer and a patterned retardation layer bonded to one side of the polarizer through the adhesive composition of any one of claims 1 to 7.

9. The composite polarizer of claim 8, 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.

10. The composite polarizer of claim 8, wherein the patterned retardation layer comprises a liquid crystal coating layer containing a reactive liquid crystal monomer comprising a benzene ring and an ester bond.

11. The composite polarizer of any one of the above 8, wherein the patterned retardation layer does not include an alignment film.

12. The composite polarizer according to item 8, wherein the corner portion is bent toward the patterned retardation layer side from the polarizer side.

13. The composite polarizer of claim 8, wherein the height difference from the peak center of the polarizer to the peak of the point 5 cm from the center of gravity is 3 mm or more.

14. The composite polarizer of claim 8, wherein the peel strength between the polarizer and the patterned retardation layer is at least 3 N / 25 mm.

15. An image display device comprising the composite polarizing plate of the above 8.

The adhesive composition of the present invention significantly improves the bonding force between the polarizer and the 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 includes a water-soluble resin and a crosslinking agent, which are used for bonding a polarizer and a patterned retardation layer and include a polyamine resin having a primary or secondary amino group, thereby significantly improving the bonding force between the polarizer and the patterned retardation layer And to improve adhesion to a display panel or the like when applied to an image display device, and a composite polarizer using the same.

Hereinafter, the present invention will be described in detail.

≪ Adhesive composition >

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

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

The adhesive composition of the present invention comprises a water-soluble resin comprising a polyamine resin having a primary or 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 water-soluble resin according to the present invention includes a polyamine resin having a primary or secondary amino group, which forms a hydrogen bond with a polar group contained in the liquid crystal coating layer of the polarizing surface polarizing layer and the patterned retardation layer, It is judged to be achieved by forming a covalent bond by performing an amidation reaction with the ester bond contained in the reactive liquid crystal monomer contained in the liquid crystal coating layer.

The polyamine resin having a primary or secondary amino group according to the present invention is not particularly limited as long as it can function as described above, and examples thereof include an allylamine polymer, a diallylamine polymer, and a vinylamine polymer. These may be used alone or in combination of two or more.

The allylamine polymer is not particularly limited and includes, for example, an allylamine polymer, an allylamine hydrochloride polymer, an allylamine amide sulfate polymer, an allylamine hydrochloride / diallylamine hydrochloride copolymer, an allylamine acetic acid salt / diallylamine acetic acid salt copolymer , Allylamine hydrochloride-dimethylallylamine hydrochloride copolymer, allylamine-dimethylallylamine copolymer, partial methoxycarbonylated allylamine polymer, and partial methylcarbonylated allylamine acetic acid salt polymer. These may be used alone or in combination of two or more.

The diallylamine polymer is not particularly limited and includes, for example, a diallylamine hydrochloride polymer, a methyldiallylamine hydrochloride polymer, a methyldiallylamineamide sulfate polymer, a methyldiallylamine acetic acid salt polymer, a diallyldimethylammonium chloride polymer, Diallyl amine hydrochloride and sulfur dioxide copolymer, diallylamine acetic acid salt and sulfur dioxide copolymer, diallyl methyl ethyl ammonium ethyl sulfate sulfur dioxide copolymer, methyl diallylamine hydrochloride and sulfur dioxide sulfuric acid copolymer, diallyldimethyl ammonium chloride Lloyd-sulfur dioxide copolymer, diallyldimethylammonium chloride-acrylamide copolymer, partial 3-chloro-2-hydroxypropylated diallylamine hydrochloride, diallyldimethylammonium chloride copolymer, diallylamine hydrochloride, maleate Acid copolymers, diallylamine amide sulfate maleic acid copolymer, maleic acid diallyl dimethyl ammonium clay It may include Read-sulfur dioxide copolymer. These may be used alone or in combination of two or more.

The vinylamine polymer is not particularly limited, and examples thereof include a vinylamine copolymer, a vinyl alcohol-vinylamine copolymer, and the like. These may be used alone or in combination of two or more.

Examples of commercially available polyamine resins include PAA-01 (Nitobosa) and PAS-21CL (Nitobosa).

The weight average molecular weight of the polyamine resin according to the present invention is not particularly limited and may be, for example, 1,000 to 70,000. When the molecular weight is within the above range, the bonding force improving effect can be maximized.

The water-soluble resin according to the present invention may further comprise a water-soluble resin commonly used in the art.

The water-soluble resin is not particularly limited, and for example, a partially saponified polyvinyl alcohol resin. A fully saponified polyvinyl alcohol resin, a carboxyl group-modified polyvinyl alcohol resin, an acetoacetyl group-modified polyvinyl alcohol resin, a methylol group-modified polyvinyl alcohol resin, an amino group-modified polyvinyl alcohol resin and a water-dispersible polyacrylate resin.

The content of the polyamine resin according to the present invention is not particularly limited within a range that can fulfill its function, for example, 10 wt% or more of the total weight of the water-soluble resin may be included. When the content is less than 10% by weight, the effect of improving the bonding force is insignificant, and a problem of durability deterioration may occur.

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 whole water-soluble resin 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 covalent bond by the amidation reaction 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 it may preferably be a monomer having a benzene ring and an ester bond.

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 can be 3 N / 25 mm or more, and preferably 4 to 5 N / 25 mm.

<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 components and the contents (based on solids) shown in Table 1 below was prepared.

division The water-soluble resin (A) The crosslinking agent (B) ingredient Weight portion ingredient Weight portion Example 1 A-1 100 B-1 5 Example 2 A-2 100 B-1 5 Example 3 A-1 / A-3 50/50 B-3 5 Example 4 A-2 / A-4 40/60 B-3 5 Example 5 A-1 / A-3 8/92 B-1 5 Example 6 A-1 100 B-2 22 Comparative Example 1 A-3 100 B-1 5 Comparative Example 2 A-4 100 B-2 5 A-1: PAA-01 (Nitobosa)
A-2: PAS-21CL (Nitobosa)
A-3: P2000 (Japanese synthetic)
A-4: P1000 (Japanese synthetic resin)
B-1: Boric acid
B-2: Glyoxal
B-3: Zinc chloride

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 4.5 ○ 3.8 Example 2 4.7 ○ 3.8 Example 3 4.2 ○ 4.1 Example 4 4.0 ○ 3.5 Example 5 3.2 ○ 3.2 Example 6 3.0 ○ 3.2 Comparative Example 1 0.9 X 2.5 Comparative Example 2 1.1 X 2.8 Comparative Example 3 1.4 ○ 0

Referring to Table 2, the composite polarizer plates bonded with the adhesive compositions of Examples 1 to 4 were excellent in peel strength of 4 N / 25 mm or more, and neither bubbles nor peeling occurred, and thus the heat resistance and the heat and humidity resistance were both excellent. Then, it was confirmed that it is possible to easily join by warping more than 3.5 mm.

In Example 5, which contained a water-soluble resin in a smaller amount than the preferred range of the present invention, and Example 6 which contained an excessive amount of a crosslinking agent, the peeling force was somewhat lowered, but still excellent effects were 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 (15)

Is used for direct bonding of the polarizer and the patterned retardation layer,
A water-soluble resin comprising a polyamine resin having a primary or secondary amino group, and a crosslinking agent.
The adhesive composition according to claim 1, wherein the patterned retardation layer comprises a liquid crystal coating layer formed on the side in contact with the polarizer.
The adhesive composition according to claim 2, wherein the liquid crystal coating layer is formed from a composition for forming a liquid crystal coating layer comprising a monomer having a benzene ring and an ester bond.
The adhesive composition according to claim 1, wherein the polyamine resin is at least one selected from the group consisting of an allylamine polymer, a diallylamine polymer, and a vinylamine polymer.
The adhesive composition according to claim 1, wherein the polyamine resin is contained in an amount of 10 wt% or more based on the total weight of the water-soluble resin.
[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 cross-linking agent is contained in an amount of 0.5 to 20 parts by weight based on 100 parts by weight of the solid-based water-soluble resin.
Polarizer, and
Wherein the polarizer comprises a patterned retardation layer directly bonded to one side of the polarizer through the adhesive composition of any one of claims 1 to 7.
[Claim 9] The composite polarizer of claim 8, 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.
9. The composite polarizer of claim 8, wherein the patterned retardation layer comprises a liquid crystal coating layer containing a reactive liquid crystal monomer comprising a benzene ring and an ester bond.
9. The composite polarizer according to claim 8, wherein the patterned retardation layer does not include an alignment film.
The composite polarizer according to claim 8, wherein the edge portion is bent toward the patterned retardation layer side from the polarizer side.
The composite polarizing plate according to claim 8, wherein the height difference from the peak center of the polarizer to the peak of the point 5 cm from the center of gravity and the center of gravity is 3 mm or more.
The composite polarizer according to claim 8, wherein the peeling force between the polarizer and the patterned retardation layer is 3 N / 25 mm or more.
An image display apparatus comprising the composite polarizing plate of claim 8.

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