KR20140147939A - Adhesive composition for polarizing plate and polarizing plate using the same - Google Patents

Abstract

The present invention relates to an adhesive composition for a polarizing plate and a polarizing plate using the same, and more specifically, to an adhesive composition for a polarizing plate that has excellent adhesion and water resistance by comprising a compound represented by chemical formula 1. The purpose of the present invention is to provide an adhesive composition for a polarizing plate that has excellent water resistance and does not peel off even in a humid heat condition, and that has excellent adhesion to a protective base material and a polarizer.

Description

[0001] The present invention relates to an adhesive composition for a polarizing plate and a polarizing plate using the adhesive composition.

The present invention relates to an adhesive composition for a polarizing plate having excellent adhesive strength and water resistance, and a polarizing plate using the same.

Polarizing plates used in various image display devices such as a liquid crystal display (LCD), an electroluminescence (EL) display, a plasma display (PDP), a field emission display (FED) and an OLED are generally made of polyvinyl alcohol alcohol, PVA) film comprises a polarizer in which an iodine compound or a dichroic polarizing material is adsorbed and oriented, a polarizer protective film is laminated on one side of the polarizer, and a polarizer protective film, a liquid crystal cell Layer structure in which a pressure-sensitive adhesive layer and a release film are laminated in this order.

2. Description of the Related Art In recent years, various types of image display devices have become larger and larger, and accordingly polarizers and polarizing plates used are also becoming larger. Therefore, the handling becomes more disadvantageous in the handling process in the process, and the amount of deformation generated under repeated high temperature and low temperature environments during use is further increased, and a polarizer excellent in durability is required.

The polarizer having excellent durability can be used without causing cracks or breakage even in an extreme environment of high temperature and high humidity. However, such a polarizer has a problem that peeling is easily caused due to a decrease in adhesive force with a protective film used in general.

The protective film and the polarizer are bonded together by an adhesive, and the adhesive for application to a polarizer having excellent durability should be excellent in not only the adhesive strength, but also the functions of water resistance and peeling force.

Korean Patent Publication No. 2010-0888572 discloses a water-based adhesive for a polarizing plate containing a polyvinyl alcohol-based resin containing an acetoacetyl group and a crosslinking agent. However, when a polarizer excellent in durability is used, I can not solve it.

Korea Patent Publication No. 2010-0888572

It is an object of the present invention to provide an adhesive composition for a polarizing plate which has an excellent water resistance not peeled off even under a humidifying heat condition, and has an excellent adhesive force to a protective substrate and a polarizer.

It is another object of the present invention to provide a polarizing plate produced using the above adhesive composition.

1. An adhesive composition for a polarizing plate comprising an? -Substituted compound represented by the following Formula 1:

[Chemical Formula 1]

(Wherein X is an oxygen atom or a sulfur atom,

R ₁ is a hydrogen atom or a straight or branched alkyl group having 1 to 6 carbon atoms which is substituted or unsubstituted with at least one hydroxyl, mercapto, amino and ammonium groups,

R ₂ is a carboxyl group; Amide group; A hydroxyl group; A mercapto group; An amino group; Ammonium group; An aryl group having 6 to 20 carbon atoms; A heteroaryl group having 4 to 20 carbon atoms; Or a linear or branched alkyl group having 1 to 4 carbon atoms and containing at least one carboxyl group, amide group, hydroxyl group, mercapto group, amino group, ammonium group, aryl group having 6 to 20 carbon atoms and heteroaryl group having 4 to 20 carbon atoms, And when R ₁ is a hydrogen atom, it is a straight or branched alkyl group having 1 to 4 carbon atoms).

2. The adhesive composition for a polarizer according to 1 above, wherein the compound represented by the general formula (1) is 20 to 70% by weight based on the total weight of the adhesive composition.

3. The composition of claim 1, wherein the compound of Formula 1 is selected from the group consisting of itaconic acid, 2-ethyl acrylic acid, 2-propyl acrylic acid, 2-butyl acrylic acid, atropic acid, benzyl methacrylic acid, (2-hydroxyethyl) acrylate, methyl 2- (hydroxymethyl) acrylate, 2-hydroxy-3-phenyl Polyethylene glycol propyl (meth) acrylate And methyl 2- (hydroxypropyl) acrylate.

4. The composition of claim 1, wherein the compound of Formula 1 is selected from the group consisting of 2-ethyl acrylate, 2-propyl acrylate, 2-butyl acrylate, methyl 2- (2-hydroxy- And methyl 2- (hydroxymethyl) acrylate.

5. The adhesive composition for a polarizing plate according to item 1, further comprising an acrylate compound.

6. The composition of claim 5 wherein said acrylate compound is selected from the group consisting of N-methyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, (Meth) acrylamide, N-methylol (meth) acrylamide, N-methylol (meth) acrylamide, (Meth) acrylamide, aminomethyl (meth) acrylamide, aminoethyl (meth) acrylamide, mercaptomethyl (meth) acrylamide, 2-hydroxy- (Meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl Acrylate, methoxyethyl (meth) acrylate, isononyl (meth) acrylate, lauryl (meth) (Meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (Meth) acrylate, and 8-hydroxyoctyl (meth) acrylate.

8. The adhesive composition for polarizing plate according to 1 above, further comprising a crosslinking agent and a radical photoinitiator.

9. A polarizing plate on which a protective film is bonded to at least one surface of a polarizer with an adhesive composition for a polarizing plate as described in any one of 1 to 8 above.

10. The polarizer of claim 9, wherein the protective film is at least one selected from the group consisting of an acrylic film, a cellulose film, a polyolefin film and a polyester film.

The adhesive composition for a polarizing plate according to the present invention exhibits excellent adhesion to a polarizer through hydrogen bonding.

The adhesive composition for a polarizing plate according to the present invention exhibits excellent water resistance.

1 is a diagram schematically showing a water resistance evaluation test method of a polarizing plate according to the present invention.

The present invention relates to an adhesive composition for a polarizing plate, which comprises a compound represented by the general formula (1) and is excellent in adhesiveness and water resistance.

Hereinafter, the present invention will be described in detail.

The? -Substituted compound represented by the following formula (1) of the present invention is a component which imparts the adhesive property and the binder function of the adhesive composition. The? -Substituted compound represented by the general formula (1) is solidified into a cured product containing a functional group capable of hydrogen bonding through a curing reaction. The cured product exhibits excellent adhesion to a protective substrate and a polarizer And excellent water resistance that is not peeled even under humid heat conditions.

In the present invention, the aforementioned '? -Substituted compound' means a compound having a substituent bonded at the? -Position of a carbonyl group.

[Chemical Formula 1]

(Wherein X is an oxygen atom or a sulfur atom,

R ₁ is a hydrogen atom or a straight or branched alkyl group having 1 to 6 carbon atoms which is substituted or unsubstituted with at least one hydroxyl, mercapto, amino and ammonium groups,

R ₂ is a carboxyl group; Amide group; A hydroxyl group; A mercapto group; An amino group; Ammonium group; An aryl group having 6 to 20 carbon atoms; A heteroaryl group having 4 to 20 carbon atoms; Or a linear or branched alkyl group having 1 to 4 carbon atoms and containing at least one carboxyl group, amide group, hydroxyl group, mercapto group, amino group, ammonium group, aryl group having 6 to 20 carbon atoms and heteroaryl group having 4 to 20 carbon atoms, And when R ₁ is a hydrogen atom, it is a straight or branched alkyl group having 1 to 4 carbon atoms).

The 'heteroaryl group' of R _{1 in} the above formula includes at least one hetero atom in the aromatic ring, and specific examples of the hetero atom include an oxygen atom, a sulfur atom and a nitrogen atom.

The meaning of inclusion in the above formula is not only the case where the functional group is substituted for the alkyl chain but also the case where the functional group is linked by an intermolecular bonding in the alkyl chain.

The kind of the compound represented by the formula (1) is not particularly limited and includes, for example, itaconic acid, 2-ethyl acrylic acid, 2-propyl acrylic acid, 2-butylacrylic acid, atropic acid, benzyl methacrylic acid, (2-hydroxy-1-methylethyl) acrylate, methyl 2- (hydroxymethyl) acrylate, 2-hydroxy Propyl (meth) acrylate, methyl 2- (hydroxypropyl) acrylate and the like, and preferably 2-ethyl acrylate, 2-propyl acrylate, 2-butyl acrylate, Methyl 2- (2-hydroxy-1-methylethyl) acrylate, and methyl 2- (hydroxymethyl) acrylate. These may be used alone or in combination.

The content of the compound represented by the formula (1) according to the present invention is not particularly limited and may be 20 to 70 parts by weight, preferably 25 to 65 parts by weight, per 100 parts by weight of the adhesive composition. When the amount of the compound represented by the formula (1) is less than 20 parts by weight, there is a problem that the adhesiveness is lowered, and when it exceeds 70 parts by weight, gelation occurs.

The adhesive composition for a polarizing plate of the present invention may further comprise an acrylate compound.

When the compound represented by Formula 1 and the acrylate compound are used at the same time, the acrylate compound is a component that imparts the adhesive property and the binder function of the adhesive composition through a curing reaction with the compound represented by Formula 1, It is possible to significantly increase the adhesiveness and water resistance.

Examples of the acrylate compound include, but are not limited to, an acrylate compound and an acrylamide compound. Specific examples of the acrylate compound include N-methyl (meth) acrylamide, N, N-dimethyl (meth) (Meth) acrylamide, N-methyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-isopropylacrylamide, (Meth) acrylamide, aminomethyl (meth) acrylamide, aminoethyl (meth) acrylamide, mercaptomethyl (meth) acrylamide, 2- (Meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, (Meth) acrylate, 2-ethylhexyl (meth) acrylate, Acrylate, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, (Meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate and 8-hydroxyoctyl , Preferably 2-hydroxyethyl acrylate, 4-hydroxybutyl acrylate, 6-hydroxyhexyl acrylate, and 8-hydroxyoctyl acrylate, which may be used alone or in combination.

In the present invention, (meth) acrylate means acrylate or methacrylate.

The content of the acrylate compound according to the present invention is not particularly limited and may be 20 to 70 parts by weight, preferably 30 to 70 parts by weight based on 100 parts by weight of the adhesive composition. When the amount of the acrylate compound is less than 20 parts by weight, adhesion and water resistance are deteriorated. When the amount of the acrylate compound is more than 70 parts by weight, the water resistance is deteriorated.

The adhesive composition for a polarizing plate of the present invention may further include a crosslinking agent and a radical photoinitiator in addition to the above compounds.

The crosslinking agent functions to improve the reactivity of the adhesive composition for a polarizing plate of the present invention. The type of the crosslinking agent is not particularly limited as long as it improves the crosslinking reactivity between the compound represented by the general formula (1) of the present invention and the acrylate compound. Preferably, an acrylate-based compound containing two or more (meth) acrylate groups which can be crosslinked with each other through a curing reaction can be used.

A-NOD, A-DOD, A-NPG, A-200, A-400, A-600, and A- APG-100, APG-400, APG-700, A-DCP, A-DOG, A-TMM, A-TMMT, A-DPH and A-TMPT. .

The content of the crosslinking agent is not particularly limited and may be 0.01 to 5 parts by weight, preferably 0.5 to 1 part by weight based on 100 parts by weight of the adhesive composition for a polarizing plate.

The radical photopolymerization initiator is not particularly limited as long as it is capable of photopolymerizing the acrylate compound of the present invention and includes, for example, a group consisting of a carbonyl photoinitiator, a benzoin ether photoinitiator and an acetophenone photoinitiator And may include at least one selected species.

Examples of commercially available radical photoinitiators that can be used in the present invention include darocur 1173, darocur 4265, darocur BP, darocur TPO, darocur MBF, irgacure 184, irgacure 500, irgacure 2959, irgacure 754, irgacure 651, irgacure 369, irgacure 907, irgacure 1300, irgacure 819, irgacure 2022, irgacure 819DW, irgacure 2100, irgacure 784, irgacure 250 and the like.

The content of the radical photoinitiator is not particularly limited and may be 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the adhesive composition for a polarizing plate. If the amount of the radical photoinitiator is less than 0.1 parts by weight, the adhesive composition of the present invention may not sufficiently cure. If the amount of the photoinitiator exceeds 10 parts by weight, unreacted photopolymerization initiator that does not participate in curing may cause yellowing.

The adhesive composition for a polarizing plate of the present invention may further comprise suitable additives as required.

The kind of the additive is not particularly limited and includes, for example, a sensitizer, a silane coupling agent, an adhesion promoter, a leveling agent, an ultraviolet absorber, an antioxidant, a dye, a processing aid, an ion trap agent, an antioxidant, , A foaming inhibitor, an antistatic agent, a fragrance, and a surfactant. These may be used alone or in combination of two or more.

The content of the additive is not particularly limited and may be 0.01 to 3 parts by weight, preferably 0.5 to 1 part by weight, based on 100 parts by weight of the adhesive composition for a polarizing plate.

The present invention also relates to a polarizing plate in which a protective film is bonded to at least one surface of a polarizer with an adhesive composition for a polarizing plate of the present invention.

A polarizer is one in which a dichroic dye is adsorbed and oriented on a stretched polyvinyl alcohol-based resin film.

The polyvinyl alcohol-based resin constituting the polarizer can be obtained by saponifying a polyvinyl acetate-based resin. Examples of the polyvinyl acetate resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate and other monomers copolymerizable therewith. Other monomers copolymerizable with vinyl acetate include acrylamide monomers having an unsaturated carboxylic acid type, an unsaturated sulfonic acid type, an olefin type, a vinyl ether type, and an ammonium group. The polyvinyl alcohol resin may also be modified. For example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. The saponification degree of the polyvinyl alcohol-based resin is usually 85 to 100 mol%, preferably 98 mol% or more. The polymerization degree of the polyvinyl alcohol-based resin is usually 1,000 to 10,000, preferably 1,500 to 5,000.

Such a polyvinyl alcohol-based resin film is used as the original film of the polarizer. The method of forming the film of the polyvinyl alcohol-based resin is not particularly limited, and a known method can be used. The thickness of the original film is not particularly limited, and may be, for example, 10 to 150 mu m.

The polarizer of the present invention is produced by continuously uniaxially stretching a polyvinyl alcohol-based film in an aqueous solution, staining with a dichroic dye and adsorbing, treating with an aqueous solution of boric acid, and washing and drying.

The uniaxial stretching of the polyvinyl alcohol film may be performed before dyeing, concurrently with dyeing, or may be performed after dyeing. If uniaxial stretching is carried out after dyeing, it may be carried out before the boric acid treatment, or may be carried out during the boric acid treatment. Of course, it is also possible to perform uniaxial stretching in a plurality of such steps. For uniaxial stretching, other rolls or rolls of different circumferences may be used. The uniaxial stretching may be either dry stretching in air or wet stretching in the state of being swollen with a solvent. The stretching ratio is usually 4 to 8 times.

As a step of dyeing a stretched polyvinyl alcohol film with a dichroic dye, for example, a method of immersing a polyvinyl alcohol film in an aqueous solution containing a dichroic dye can be used. As the dichroic dye, iodine or a dichroic dye is used. It is preferable that the polyvinyl alcohol film is pre-immersed in water before dyeing to swell.

When iodine is used as the dichroic dye, a method in which a polyvinyl alcohol-based film is dipped in an aqueous solution for dyeing usually containing iodine and potassium iodide may be used. Usually, the content of iodine in an aqueous solution for dyeing is 0.01 to 1 part by weight with respect to 100 parts by weight of water (distilled water), and the content of potassium iodide is 0.5 to 20 parts by weight with respect to 100 parts by weight of water. The temperature of the aqueous solution for dyeing is usually 20 to 40 占 폚, and the immersion time (dyeing time) is usually 20 to 1,800 seconds.

When a dichroic dye is used as the dichroic dye, a method of dying and dyeing a polyvinyl alcohol-based resin film in an aqueous solution containing a water-soluble dichroic dye is generally employed. The content of the dichroic dye in this aqueous solution is usually 1 × 10 ^-4 to 10 parts by weight, preferably 1 × 10 ^-3 to 1 part by weight, per 100 parts by weight of water. The aqueous solution may contain an inorganic salt such as sodium sulfate as a dyeing aid. The dye aqueous solution used for dyeing usually has a temperature of 20 to 80 DEG C, and the immersion time for this aqueous solution is usually 10 to 1,800 seconds.

The step of treating the dyed polyvinyl alcohol film with boric acid can be carried out by immersing it in an aqueous solution containing boric acid. The content of boric acid in an aqueous solution containing boric acid is usually 2 to 15 parts by weight, preferably 5 to 12 parts by weight based on 100 parts by weight of water. When iodine is used as the dichroic dye, it is preferable that the aqueous solution containing boric acid contains potassium iodide. The content thereof is usually 0.1 to 15 parts by weight, preferably 5 to 12 parts by weight per 100 parts by weight of water. The temperature of the boric acid-containing aqueous solution is usually 50 ° C. or higher, preferably 50 to 85 ° C., and more preferably 60 to 80 ° C. The immersing time is usually 60 to 1,200 seconds, preferably 150 to 600 seconds, Preferably 200 to 400 seconds.

After the boric acid treatment, the polyvinyl alcohol film is usually washed with water and dried. The washing treatment can be carried out by immersing the boric acid-treated polyvinyl alcohol-based film in water. The water temperature of the water treatment is usually 5 to 40 占 폚, and the immersion time is usually 1 to 120 seconds. After washing with water, the polarizer can be obtained. The drying treatment can be usually carried out using a hot air dryer or a far infrared ray heater. The drying treatment temperature is usually 30 to 100 占 폚, preferably 50 to 80 占 폚, and the drying time is usually 60 to 600 seconds, preferably 120 to 600 seconds.

The thickness of the polarizer according to the present invention is not particularly limited, but may be, for example, 5 to 40 탆.

The kind of the protective film is not particularly limited as long as it is excellent in transparency, mechanical strength, thermal stability, moisture shielding property, isotropy, and the like. For example, the protective film is made of an acrylic resin film, a cellulose resin film, a polyolefin resin film and a polyester resin film Various transparent resin films containing at least one kind selected from the group consisting of

Specific examples of the protective film include acrylic resin films such as polymethyl (meth) acrylate and polyethyl (meth) acrylate; Polyester based resin films such as polyethylene terephthalate, polyethylene isophthalate, polyethylene naphthalate and polybutylene terephthalate; Cellulose-based resin films such as diacetylcellulose and triacetylcellulose; Polyolefin-based resin films such as polyethylene, polypropylene, cyclo-based or norbornene structures, polyolefin-based or ethylene-propylene copolymer; And the like, but the present invention is not limited thereto.

The thickness of the protective film is not particularly limited, but may be 10 to 200 占 퐉, preferably 10 to 150 占 퐉. When the thickness of the protective film is 10 to 200 탆, when the polarizer protective film is laminated on both sides of the polarizer, the respective protective films may have the same or different thicknesses.

The adhesive composition for a polarizing plate according to the present invention can be applied to at least one side of the polarizer to form an adhesive layer, and a polarizer and a protective film can be formed on the adhesive layer using a known method Can be bonded.

The thickness of the adhesive layer formed by applying the adhesive composition of the present invention is not particularly limited, but may be, for example, 0.01 to 10 탆, preferably 0.5 to 5 탆. When the thickness of the adhesive layer is 0.5 탆 or less, there is a high possibility that air bubbles are mixed at the time of bonding, and when the thickness of the adhesive layer is 5 탆 or more, the price increases.

In order to improve the adhesion, the surface of the polarizer and / or the protective film may be suitably subjected to a surface treatment such as a chemical treatment such as a primer treatment, a plasma treatment, a corona treatment, or a dry treatment or a saponification (alkali) treatment . Examples of the saponification (alkali) treatment include a method of immersing in an aqueous solution of an alkali such as sodium hydroxide or potassium hydroxide.

The other side of the polarizer to which the protective film is bonded on one side may be suitably subjected to surface treatment such as hard coat treatment, antireflection treatment, anti-stick treatment, diffusion or anti-glare treatment as required.

In addition to the above-described surface treatment, the other surface of the polarizer to which the protective film is bonded on one surface may further be laminated with a surface treatment layer such as a hard coating layer, an antireflection layer, an antiglare layer and an antistatic layer, An optical functional film may be further laminated.

The type of the optically functional film is not particularly limited. For example, an optically compensatory film in which a liquid crystalline compound or a polymer compound thereof is oriented on the surface of a base material, an optically compensatory film which transmits polarized light of any kind, A retardation film including a polycarbonate resin, a retardation film including a cyclic polyolefin resin, an anti-glare function film having a concavo-convex shape on its surface, an additional film having a surface antireflection treatment, A transflective film having both a reflective function and a transmissive function, and the like.

Such a polarizing plate can be applied to all normal image devices.

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.

Manufacturing example  - Polarizer  Produce

A polyvinyl alcohol film having a thickness of 75 탆 and an average degree of polymerization of 2,400 and a saponification degree of 99.9 mol% or more was uniaxially stretched by a dry method about 5 times and immersed in water (distilled water) at 60 캜 for 1 minute while maintaining the stretched state And immersed for 60 seconds in an aqueous solution at 28 DEG C in which the weight ratio of after-iodine / potassium iodide / distilled water was 0.05 / 5/100. Thereafter, the substrate was immersed in an aqueous 72 ° C aqueous solution having a weight ratio of potassium iodide / boric acid / distilled water of 8.5 / 8.5 / 100 for 300 seconds, washed with distilled water at 26 ° C for 20 seconds and dried at 65 ° C to remove iodine Adsorbed polarizers were prepared.

Example  One

50 parts by weight of 4-hydroxybutyl acrylate (TCI), 1 part by weight of a cross-linking agent A-TMM (HANNONG), 5 parts by weight of a radical photoinitiator TPO ) Were mixed to prepare an adhesive composition.

The adhesive composition was coated on both sides of the polarizer on which the iodine adsorbed orientation was prepared so as to have a thickness of 2 탆 and then coated with a corona-treated triacetyl cellulose protective film (KC8UX, Konica) and a corona- A polarizing plate was prepared by UV curing a high-pressure mercury lamp (UVA cumulative light quantity: 500 mJ / cm 2, illuminance: 500 mW / cm 2) after bonding a zeolite-based norbornene-based COP protective film.

Example  2 to 11 and Comparative Example  1 to 6

An adhesive composition and a polarizing plate were prepared in the same manner as in Example 1, except that the components and the composition ratios described in the following Table 1 were used (note that BYK-331 is a surfactant (BYK-Chemie)).

Monomer Cross-linking agent additive Radical photoinitiator Formula 1 (parts by weight) Acrylate A (parts by weight) Acrylate B (parts by weight) Acrylate C (parts by weight) Example 1 The 2-ethyl acrylic acid (44) 4-hydroxybutyl acrylate (50) A-TMM (1) TPO (5) Example 2 Ethyl Acrylic Acid (24) 4-hydroxybutyl acrylate (70) A-TMM (1) TPO (5) Example 3 The 2-ethyl acrylic acid (54) 4-hydroxybutyl acrylate (40) A-TMM (1) TPO (5) Example 4 Ethyl Acrylic Acid (64) 4-hydroxybutyl acrylate (30) A-TMM (1) TPO (5) Example 5 Itaconic Acid (44) 4-hydroxybutyl acrylate (50) A-TMM (1) TPO (5) Example 6 Atropic acid (44) 4-hydroxybutyl acrylate (50) A-TMM (1) TPO (5) Example 7 Benzyl methacrylic acid (44) 4-hydroxybutyl acrylate (50) A-TMM (1) TPO (5) Example 8 Methyl 2- (2-hydroxy-1-methylethyl) acrylate (44) 4-hydroxybutyl acrylate (50) A-TMM (1) TPO (5) Example 9 The 2-ethyl acrylic acid (44) 4-hydroxybutyl acrylate (49.5) A-TMM (1) BYK-331 (0.5) TPO (5) Example 10 Ethyl Acrylic Acid (95) TPO (5) Example 11 Ethyl Acrylic Acid (45) N-acryloylmorpholine
(50) TPO (5) Comparative Example 1 4-hydroxybutyl acrylate (95) TPO (5) Comparative Example 2 4-hydroxybutyl acrylate (50) N-acryloylmorpholine (45) TPO (5) Comparative Example 3 4-hydroxybutyl acrylate (50) N-acryloylmorpholine (44) A-TMM (1) TPO (5) Comparative Example 4 4-hydroxybutylacrylamide (50) N-acryloylmorpholine (45) TPO (5) Comparative Example 5 N-acryloylmorpholine
(95) TPO (5) Comparative Example 6 N-hydroxyethyl acrylamide (95) TPO (5)

Test Example

The following evaluation tests were performed on each of the polarizers obtained in Examples and Comparative Examples, and the results are shown in Table 2 below.

(1) Adhesion (Cutter Evaluation)

The polarizing plates prepared in Examples and Comparative Examples were allowed to stand at room temperature for 1 hour, and then a cutter blade was inserted between each film of the polarizing plate (between the polarizer and the polarizer protective film), and the blade when the blade was pushed was entered And evaluated according to the following criteria.

[Assessment Methods]

A: The cutter blade does not enter any film.

○: When pushing the blade, it stops when the blade reaches 1 to 2 mm between at least one of the films.

?: When the blade is pushed, it stops when the blade enters 3 to 5 mm between at least one of the films.

X: When pushing the blade, the blade is easily inserted between at least one of the films.

(2) Water resistance

The polarizers prepared in Examples and Comparative Examples were allowed to stand for 24 hours under an environment of 23 ° C and 55% relative humidity, and tested for water resistance. First, the polarizing plate was cut into a rectangular shape of 5 cm x 2 cm with the absorption axis (stretching direction) of the polarizing plate as the long side to prepare a sample, and the dimension in the long side direction was measured accurately. Here, the sample exhibits uniform color uniformly over the entire surface due to iodine adsorbed on the polarizer. As shown in Fig. 1, (A) shows that the short side of the sample 1 is gripped by the grip portion 5 before immersion in the hot water, (B) Showing a shrunk sample 4 after immersing about 80% in the longitudinal direction in a hot water tank at 60 캜 for 4 hours. When the immersion is completed, the sample (4) is taken out of the water tank to wipe out moisture, and the degree of shrinkage of the polarizer is measured. Specifically, the distance from the end 1a of the protective film at the center of the short side of the sample 1 to the end of the polarizer 4 contracted was measured, and this was taken as the contraction length. 1B, the polarizer 4 located at the center of the polarizing plate shrinks due to the immersion of hot water, and the region 2 where the polarizer 4 is not present between the two protective films is formed. In addition, iodine elutes from the peripheral portion of the polarizer 4 which is in contact with the hot water due to the hot water immersion, and a portion 3 in which the color is missing in the peripheral portion of the sample 1 is generated. The degree of discoloration was measured as the distance from the end of the shrunk polarizer 4 at the center of the short side of the sample 1 to the region where the color unique to the polarizing plate remained, and this was taken as the iodine drop length. The total erosion length X means the total erosion length X from the end 1a of the sample 1 at the center of the short side of the sample 1 to the total length of the sample 1 from the end 1a of the sample 1, This is the distance to the area where the color remains. (Water resistance) in the presence of water as the shrinkage length, the iodine dropout length and the total erosion length (X) are smaller.

[Assessment Methods]

?: Total erosion length (X) < 2 mm

?: 2 mm? Total erosion length (X) < 3 mm

?: 3 mm? Total erosion length (X) <5 mm

X: 5 mm? Total erosion length (X)

(3) Peel force (N / mm)

The polarizing plates prepared in Examples and Comparative Examples were allowed to stand at room temperature for 1 hour and then joined using a pressure roller on a soda glass using a hand roller and then subjected to autoclave treatment under the conditions of a pressure of 2 atm, To remove the bubbles generated during the bonding. Soda glass / tackifier / corona treated unsaponified cellulosic film or corona treated norbornene based COP film / polarizer / corona treated unsaponified cellulosic film or corona treated norbornene based COP film construction, in soda glass direction , A knife was inserted between a corona-treated unoriented cellulosic film or a corona-treated norbornene-based COP film and a polarizer, and a 180 ° peeling force (measuring speed 300 mm / min) Measured

Peel force average (N / 25 mm)

= (Cellulose film varnish + norbornene-based COP film peeling force) / 2

Adhesiveness Water resistance Peel force Example 1 ◎ ◎ 2.5 Example 2 ○ ◎ 1.6 Example 3 ◎ ◎ 2.9 Example 4 ◎ ◎ 3.1 Example 5 ○ ○ 1.3 Example 6 ○ ○ 1.1 Example 7 ○ ○ 0.9 Example 8 ◎ ◎ 2.1 Example 9 ◎ ◎ 1.6 Example 10 ○ △ 1.1 Example 11 ○ ○ 1.0 Comparative Example 1 △ X 0.3 Comparative Example 2 △ X 0.7 Comparative Example 3 ○ △ 0.8 Comparative Example 4 △ X 1.0 Comparative Example 5 △ X 0.4 Comparative Example 6 △ X 0.3

As shown in Table 2, in Examples 1 to 11 in which the polarizer and the protective film were bonded to each other with the adhesive composition for a polarizing plate according to the present invention, it was confirmed that the adhesive property, the water resistance, and the peeling force were excellent.

It was confirmed that the water resistance and peel strength of Example 10 containing the compound of Formula 1 in a rather excessive amount were slightly lower than those of the other Examples in which the acrylate compound and the crosslinking agent were mixed.

Comparative Examples 1 to 6, which were obtained by polymerizing only acrylate compounds, exhibited remarkably low adhesiveness and water resistance and lowered peel strength. Comparative Example 3, which further included a crosslinking agent, exhibited similar properties to those of Example 10 which did not contain a crosslinking agent Respectively.

Claims (10)

An adhesive composition for a polarizing plate comprising a? -Substituted compound represented by the following formula
[Chemical Formula 1]

(Wherein X is an oxygen atom or a sulfur atom,
R ₁ is a hydrogen atom; Or a linear or branched alkyl group having 1 to 4 carbon atoms which is substituted or unsubstituted with at least one hydroxyl, mercapto, amino, ammonium, aryl, or heteroaryl group,
R ₂ is a carboxyl group; Amide group; A hydroxyl group; A mercapto group; An amino group; Ammonium group; An aryl group having 6 to 20 carbon atoms or a heteroaryl group having 4 to 20 carbon atoms, which contains at least one hydroxyl group, a mercapto group, an amino group, an ammonium group, an alkoxy group having 1 to 3 carbon atoms, Or a linear or branched alkyl group or alkenyl group having 1 to 4 carbon atoms which is unsubstituted or substituted with at least one hydroxyl, mercapto, amino, ammonium, aryl group having 6 to 20 carbon atoms, heteroaryl group having 4 to 20 carbon atoms And when R ₁ is a hydrogen atom, it is a straight or branched alkyl group or alkenyl group having 1 to 4 carbon atoms).
The adhesive composition for a polarizing plate according to claim 1, wherein the compound represented by Formula 1 is 20 to 70 parts by weight based on 100 parts by weight of the adhesive composition.
The compound according to claim 1, wherein the compound represented by Formula 1 is selected from the group consisting of crotonic acid, fumaric acid, 4-methyl-pent-2-enoic acid, sorbit acid, ethylsorbate, 3- (2E) 3-phenyl-2-propenoate, p-cumaric acid, methyl cinnamate, S- 4-methoxy cinnamic acid, trans-isoperuic acid, trans-peruic acid and ethyl 3- (N, N-dimethylamino) acrylate &Lt; RTI ID = 0.0 &gt; 1, &lt; / RTI &gt;
[4] The compound according to claim 1, wherein the compound represented by Formula 1 is at least one selected from the group consisting of p-cumaric acid, cupric acid, ethylsorbate, methyl cinnamate, and 2,4-dihydroxycinnamic acid. / RTI &gt;
The adhesive composition for a polarizing plate according to claim 1, further comprising an acrylate compound.
[6] The method of claim 5, wherein the acrylate compound is at least one selected from the group consisting of N-methyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, (Meth) acrylamide, N-methylol (meth) acrylamide, N-methylol (meth) acrylamide, Amide, aminomethyl (meth) acrylamide, aminoethyl (meth) acrylamide, mercaptomethyl (meth) acrylamide, 2-hydroxy- (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, (Meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, (Meth) acrylate, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2- Wherein the adhesive composition is at least one selected from the group consisting of 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate and 8-hydroxyoctyl (meth) acrylate.
[6] The method of claim 5, wherein the acrylate compound is at least one selected from the group consisting of 2-hydroxyethyl acrylate, 4-hydroxybutyl acrylate, 6-hydroxyhexyl acrylate and 8- / RTI &gt;
The adhesive composition for a polarizing plate according to claim 1, further comprising a crosslinking agent and a radical photoinitiator.
Wherein a protective film is bonded to at least one surface of the polarizer with the adhesive composition for a polarizing plate according to any one of claims 1 to 8.
The polarizer according to claim 9, wherein the protective film is at least one selected from the group consisting of an acrylic film, a cellulose film, a polyolefin film, and a polyester film.

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