KR101542620B1 - Adhesive film for polarizing plate, adhesive composition for the same, polarizing plate comprising adhesive layer including the same and display apparatus comprising the same - Google Patents

Abstract

(상기에서, *는 원소의 연결 부위이고,
X는 피리딜기 또는 피리미디닐기이고,
Y는 -O-, -S-, -NR-, -(C=O)NR-, -NR(C=O)-(상기에서, R은 수소 또는 탄소수 1-5의 알킬기이다), -(C=O)-, -O(C=O)- 또는 -(C=O)O-이고,
n은 2-16의 정수이다).The present invention relates to a pressure sensitive adhesive film for a polarizing plate comprising a cured product of a composition comprising a (meth) acrylic copolymer having a functional group of the following formula (1), a pressure sensitive adhesive composition for a polarizing plate for the same, and a polarizing plate and a display device will be:
≪ Formula 1 >

(Where * is the connecting site of the element,
X is a pyridyl group or a pyrimidinyl group,
Y is -O-, -S-, -NR-, - (C = O) NR-, -NR (C = O) - (wherein R is hydrogen or an alkyl group having 1-5 carbon atoms) C = O) -, -O (C = O) - or - (C = O)
and n is an integer of 2 to 16).

Description

[0001] The present invention relates to a pressure-sensitive adhesive film for a polarizing plate, a pressure-sensitive adhesive composition for a polarizing plate, a polarizing plate including the same, and a display device including the polarizing plate.

The present invention relates to a pressure-sensitive adhesive film for a polarizing plate, a pressure-sensitive adhesive composition for a polarizing plate for the same, a polarizing plate including the same, and a display device comprising the same. More specifically, the present invention relates to a pressure-sensitive adhesive film for a polarizing plate, a pressure-sensitive adhesive composition for a polarizing plate, a polarizing plate including the polarizing plate, and a display device therefor, which improves light leakage of the polarizing plate and has no deterioration in durability under high- .

The liquid crystal display comprises a liquid crystal cell and a liquid crystal panel including a polarizing plate attached to both sides of the liquid crystal cell. The polarizing plate is composed of a polyvinyl alcohol (PVA) film and a protective film for protecting both sides of the PVA film. The polarizing plate is attached to the liquid crystal cell using an adhesive. Each film constituting the polarizing plate is formed by a laminated structure of films having different molecular structures, and each of the films has different physical and optical characteristics. As the film is used for a long period of time due to external environmental requirements such as temperature and humidity, the molecular structure and physical properties of the films change. In particular, in the case of the PVA film, the chains of the polymer are oriented in a certain direction, and when a long time passes after the orientation of the film, shrinkage due to the stress relaxation action occurs. Furthermore, if exposed to harsh environments such as high temperature and high humidity, the relaxation effect of the film is further accelerated. Stress is generated in the adhesive film by shrinkage or expansion of the film generated at this time. If the pressure-sensitive adhesive film does not have durability such as heat resistance and heat resistance, it is liable to cause lifting phenomenon in which the film peels off from the liquid crystal cell under high temperature and high humidity conditions, or bubbles are likely to appear.

On the other hand, light leakage phenomenon occurs in which the peripheral portion of the liquid crystal panel becomes brighter than the central portion due to the internal stress generated by the shrinkage and expansion of the polarizing plate itself during long-term use under high temperature or high humidity conditions.

 The pressure sensitive adhesive used for attaching the polarizing plate to the liquid crystal cell has to satisfy both of the above-described durability such as heat resistance and humidity resistance, and at the same time, the function of improving the light leakage phenomenon. However, since the physical properties of the required pressure-sensitive adhesive are very complicated and conflict with each other, it is difficult to completely satisfy all of them. In order to improve the light leakage phenomenon and improve the durability of the pressure-sensitive adhesive, various pressure-sensitive adhesive compositions have been proposed.

For example, Korean Patent Publication No. 2010-0019401 discloses a method of inducing birefringence of a pressure-sensitive adhesive itself by using an aromatic functional group to relax light leakage. However, it is difficult to completely satisfy the durability of the pressure-sensitive adhesive.

An object of the present invention is to provide an adhesive film for a polarizing plate which is excellent in durability under high temperature and high humidity and can improve the light leakage phenomenon.

Another object of the present invention is to provide a pressure-sensitive adhesive composition for a polarizing plate capable of reducing the time required for the aging process of a pressure-sensitive adhesive.

Another object of the present invention is to provide a pressure-sensitive adhesive film and a pressure-sensitive adhesive composition for a polarizing plate comprising a copolymer for a pressure-sensitive adhesive which is easy to polymerize and has excellent adhesion.

It is still another object of the present invention to provide a polarizing plate comprising the pressure-sensitive adhesive film for a polarizing plate or the pressure-sensitive adhesive composition for a polarizing plate.

It is still another object of the present invention to provide a display device including the polarizer.

An adhesive film for a polarizing plate which is one aspect of the present invention may comprise a cured product of a composition comprising a (meth) acrylic copolymer having a functional group of the following formula (1)

≪ Formula 1 >

(Wherein X is a pyridyl group or a pyrimidinyl group,

Y is -O-, -S-, -NR-, - (C = O) NR-, -NR (C = O) - (wherein R is hydrogen or an alkyl group having 1-5 carbon atoms) C = O) -, -O (C = O) - or - (C = O)

and n is an integer of 2 to 16).

Another aspect of the present invention is a pressure sensitive adhesive composition for a polarizing plate, which comprises a (meth) acrylic copolymer of a monomer mixture comprising a monomer of the following formula (2) and a curing agent:

(2)

(Wherein X is a pyridyl group or a pyrimidinyl group,

Y is -O-, -S-, -NR-, - (C = O) NR-, -NR (C = O) - (wherein R is hydrogen or an alkyl group having 1-5 carbon atoms) C = O) -, -O (C = O) - or - (C = O)

n is an integer of 2 to 16,

And R < _{1 >} is hydrogen or an alkyl group having 1-5 carbon atoms.

Another aspect of the present invention is a polarizing plate comprising a polarizer, a protective film laminated on at least one surface of the polarizer, and an adhesive layer laminated on one side of the protective film, wherein the adhesive layer has a functional group (Meth) acryl-based copolymer.

≪ Formula 1 >

(Wherein X is a pyridyl group or a pyrimidinyl group,

Y is -O-, -S-, -NR-, - (C = O) NR-, -NR (C = O) - (wherein R is hydrogen or an alkyl group having 1-5 carbon atoms) C = O) -, -O (C = O) - or - (C = O)

and n is an integer of 2 to 16).

A display device that is another aspect of the present invention may include the polarizer.

The present invention provides a pressure-sensitive adhesive film for a polarizing plate which is excellent in durability under high temperature and high humidity and can improve light leakage phenomenon. The present invention provides a pressure-sensitive adhesive composition for a polarizing plate comprising a copolymer for a pressure-sensitive adhesive which can reduce the time required for the aging process of a pressure-sensitive adhesive, is easy to polymerize, and has excellent adherence, and an adhesive film comprising the same.

1 is a cross-sectional view of a polarizer according to one embodiment of the present invention.
2 is a cross-sectional view of a polarizing plate according to another embodiment of the present invention.
3 is a view showing a position of measurement of light leakage on a panel for measuring light leakage.
4 is a cross-sectional view of a display device according to an embodiment of the present invention.

As used herein, 'substituted' in 'substituted or unsubstituted' may mean that at least one hydrogen atom is substituted with a C1-C10 alkyl group, a C1-C10 cycloalkyl group, a C6-C10 aryl group, a halogen or a hydroxy group.

In the present specification, the term "vinyl-based monomer" may include a vinyl group or a (meth) acrylate group.

In this specification, '*' denotes an inter-element connecting site.

An adhesive film for a polarizing plate which is one aspect of the present invention may comprise a cured product of a composition comprising a (meth) acrylic copolymer having a functional group of the following formula (1)

≪ Formula 1 >

(Where * is the connecting site of the element,

X is a pyridyl group or a pyrimidinyl group,

Y is -O-, -S-, -NR-, - (C = O) NR-, -NR (C = O) - (wherein R is hydrogen or an alkyl group having 1-5 carbon atoms) C = O) -, -O (C = O) - or - (C = O)

and n is an integer of 2 to 16).

The copolymer may include the functional group of Formula 1 in the side chain of the copolymer.

The functional group of the formula (1) may be contained in the copolymer in an amount of 1-50% by weight. Within this range, there may be an effect of reliability and light leakage improvement.

The peel strength of the polarizing plate adhesive film may be 0.1 kgf / 25 mm-1.0 kgf / 25 mm. In this range, the polarizing plate can be used for a polarizing plate adhesive film which can be adhered to a glass plate including a liquid crystal panel easily, reattachment is easy, and reliability is excellent. The peeling strength measurement method can be referred to the following experimental examples.

The thickness of the pressure sensitive adhesive film for a polarizing plate may be 5 占 퐉 to 100 占 퐉. In the above range, it can be used as a polarizing plate adhesive film.

The above-mentioned pressure sensitive adhesive film for a polarizing plate can be used for the purpose of sticking an optical film to each other on a polarizing plate or adhering an optical film to a panel. The optical film may include a retardation film or a protective film.

The pressure-sensitive adhesive film for a polarizing plate may be a dried product or a cured product of a pressure-sensitive adhesive composition comprising a (meth) acrylic copolymer having a functional group of Formula 1 and a curing agent. The adhesive film may be formed by drying and / or aging the composition and may be prepared by further curing.

The aging can be performed at 35 DEG C for 1 hour to 1 week, but is not limited thereto.

The curing can be performed by a heat curing method, but is not limited thereto.

For example, an adhesive film can be prepared by coating the above composition on a release film (for example, a polyethylene terephthalate film), followed by drying and curing at 25 ° C to 50 ° C.

The pressure-sensitive adhesive composition for a polarizing plate, which is another aspect of the present invention, may include a (meth) acrylic copolymer and a curing agent.

( Meta ) Acrylic copolymer

(Meth) acrylic copolymer may include a functional group represented by the following formula (1) in the side chain:

≪ Formula 1 >

(Where * is the connecting site of the element,

X is a pyridyl group or a pyrimidinyl group,

Y is -O-, -S-, -NR-, - (C = O) NR-, -NR (C = O) - (wherein R is hydrogen or an alkyl group having 1-5 carbon atoms) C = O) -, -O (C = O) - or - (C = O)

and n is an integer of 2 to 16).

The (meth) acrylic copolymer may be a copolymer of a monomer mixture comprising a monomer of the following formula (2):

(2)

(Wherein X is a pyridyl group or a pyrimidinyl group,

Y is -O-, -S-, -NR-, - (C = O) NR-, -NR (C = O) - (wherein R is hydrogen or an alkyl group having 1-5 carbon atoms) C = O) -, -O (C = O) - or - (C = O)

n is an integer of 2 to 16,

And R < _{1 >} is hydrogen or an alkyl group having 1-5 carbon atoms.

X is a pyridyl group or a pyrimidinyl group, the position of nitrogen in the aromatic group may be changed.

Preferably, X may be any of the following structures:

;

;

;

;

;

.

;

;

;

;

;

.

(Where * is the connecting site for Y)

Preferably, Y is -O-, and the monomer may be pyridyloxyalkyl (meth) acrylate or pyrimidinyloxyalkyl (meth) acrylate.

"- (-CH ₂ -) _n -" may be a linear or branched alkylene group.

n may be an integer of 2-16. Within this range, phase separation of the copolymer may not occur in the pressure-sensitive adhesive composition or the pressure-sensitive adhesive film.

The monomer is included in the (meth) acrylic copolymer to shorten the aging time of the pressure-sensitive adhesive composition. Further, it is possible to provide an adhesive film for a polarizing plate improved in durability and light leakage.

The monomer may be contained in the monomer mixture or the (meth) acrylic copolymer in an amount of 1-50% by weight, preferably 1-30% by weight. In this range, the cohesion of the copolymer may not occur, the durability of the pressure-sensitive adhesive film and the light-shielding effect may be improved, and the aging time of the pressure-sensitive adhesive composition may be shortened.

The monomer of Formula 2 may be synthesized by a conventional method.

The (meth) acrylic copolymer may contain, in addition to the monomer, a copolymer of a monomer mixture containing at least one of a vinyl monomer having an alkyl group, a vinyl monomer having a hydroxy group, a vinyl monomer having a carboxylic acid group, and a vinyl monomer having a heterocyclic ring Lt; / RTI >

The vinyl-based monomer having an alkyl group is a (meth) acrylic monomer, and may include a linear or branched (meth) acrylic acid ester having an alkyl group having 1 to 20 carbon atoms. (Meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, Acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, isooctyl (meth) acrylate, hexyl (meth) acrylate, (Meth) acrylate, decyl (meth) acrylate and dodecyl (meth) acrylate, but are not limited thereto.

The (meth) acrylic monomer having an alkyl group may be contained in the copolymer in an amount of 49 to 98% by weight, preferably 69 to 98% by weight. Within this range, adhesion and tackiness may be good.

The (meth) acrylate monomer having a hydroxyl group is preferably a (meth) acrylate monomer having a terminal or an alkyl group having 2 to 20 carbon atoms, a cycloalkyl group having 5 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, Acrylic acid ester. (Meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl 1-chloro-2-hydroxypropyl (meth) acrylate, diethylene glycol mono (meth) acrylate, 1,4-cyclohexanedimethanol mono (meth) acrylate, (Meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, neopentyl glycol mono (meth) acrylate, trimethylolpropane di (Meth) acrylate, 4-hydroxycyclohexyl (meth) acrylate, trimethylol ethane di (meth) acrylate, 2-hydroxy- Acrylate, and cyclohexane dime (Meth) acrylate, and mono (meth) acrylate, but are not limited thereto.

The (meth) acrylic monomer having a hydroxy group may be contained in an amount of 10 wt% or less, preferably 0-10 wt%, more preferably 0.1-5 wt%, of the copolymer. Within the above range, it is possible to obtain a crosslinked site, which results in a high degree of crosslinking and an increase in adhesion of the pressure-sensitive adhesive.

The vinyl monomer having a carboxylic acid group may be at least one selected from the group consisting of (meth) acrylic acid and? -Carboxyethyl (meth) acrylate as the (meth) acrylic monomer, but is not limited thereto.

The (meth) acrylic monomer having a carboxylic acid group may be contained in an amount of 10% by weight or less, preferably 0-10% by weight, more preferably 0.1-5% by weight in the (meth) acrylic copolymer. Within the above range, a result of increasing the adhesive force of the pressure-sensitive adhesive can be obtained.

The vinyl monomer having a heterocyclic ring may be a saturated or unsaturated aliphatic or alicyclic heterocyclic ring having 2 to 10 carbon atoms having a hetero atom (e.g., at least one of nitrogen, oxygen and sulfur) or an aromatic heterocyclic ring having 4 to 20 carbon atoms It can be a monomer. For example, it may include acryloylmorpholine.

The vinyl monomer having a heterocyclic ring may be contained in an amount of 10 wt% or less, preferably 0-5 wt%, of the copolymer. Within the above range, endurance reliability can be improved, and the rework characteristics can be good.

The (meth) acrylic copolymer may have a weight average molecular weight of 200,000 g / mol-2,000,000 g / mol, preferably 80,000 g / mol-1 million g / mol. Within this range, it is possible to provide a good stress relaxation force to the polarizing plate, increase the adhesive force to the glass panel, thereby simultaneously providing high shrinkage resistance and minimizing light leakage.

The (meth) acrylic copolymer may have a polydispersity index (PDI) of 1.1-12.0, preferably 1.5-8.0. In the above-mentioned range, there is no desorption, bubble and wrinkle formation at the corner and the end of the polarizer, and the reliability of durability can be improved.

The (meth) acrylic copolymer may have a glass transition temperature of -50 ° C or higher, preferably -40 ° C to + 20 ° C. Within this range, it is possible to provide a good stress relaxation force to the polarizing plate, increase the adhesive force to glass, simultaneously provide high shrinkage resistance, and minimize light leakage.

The method for producing the (meth) acrylic copolymer is not particularly limited, and can be produced by a solution polymerization method, a photopolymerization method, a bulk polymerization method, an emulsion polymerization method, or an emulsion polymerization method. Preferably, the (meth) acrylic copolymer is produced by a solution polymerization method, and the polymerization temperature may be preferably from 50 ° C to 140 ° C.

As an initiator in the polymerization, an azo-based polymerization initiator such as azobisisobutyronitrile or azobiscyclohexanecarbonitrile; And / or peroxides such as benzoyl peroxide or acetyl peroxide, and the like.

The initiator may be included in an amount of 0.01-10 parts by weight based on 100 parts by weight of the vinyl monomer having an alkyl group. Within this range, the copolymer can be sufficiently polymerized.

The solvent for polymerization is not particularly limited, but one or more of ethyl acetate and methyl ethyl ketone may be used.

The (meth) acrylic copolymer may be contained in an amount of 70 to 99% by weight, preferably 93 to 99.8% by weight, based on the solid content of the pressure-sensitive adhesive composition. Within the above range, it is advantageous to form a coating film, and the composition of the pressure-sensitive adhesive may be uniformly distributed when compounded.

Hardener

The pressure-sensitive adhesive composition may further comprise a curing agent.

The curing agent may include at least one of an isocyanate-based, epoxy-based, aziridine-based, melamine-based, amine-based, imide-based, carbodiimide-based and amide-based.

Examples of the isocyanate curing agent include toluene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, hydrogenated tolylene diisocyanate, isophorone diisocyanate, 1,3-xylene diisocyanate, Diisocyanate, diphenylmethane-4,4-diisocyanate, 1,3-bisisocyanatomethylcyclohexane, tetramethylxylene diisocyanate, 1,5-naphthalene diisocyanate, hexamethylene diisocyanate, 2,2,4- Trimethylolpropane-modified toluene diisocyanate, trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, trimethylolpropane-modified toluene diisocyanate, trimethylolpropane-modified tolylene diisocyanate, trimethylolpropane trilene diisocyanate adduct, trimethylolpropane Xylylene diisocyanate adduct, triphenylmethane triisocyanate, Methylene bistriisocyanate, and the like, but the present invention is not limited thereto. These may be used alone or in combination of two or more.

The curing agent may be contained in an amount of 0.1 to 40% by weight, preferably 0.1 to 30% by weight, more preferably 0.1 to 20% by weight based on the solid content of the pressure-sensitive adhesive composition. Within the above range, the pressure-sensitive adhesive is excellent in endurance reliability, and the change in the component and physical properties with time can be small.

Silane coupling agent

The pressure-sensitive adhesive composition may further include a silane coupling agent.

As the silane coupling agent, those conventionally known to those skilled in the art can be used. For example, silicon compounds having an epoxy structure such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane and 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane; A polymerizable unsaturated group-containing silicon compound such as vinyltrimethoxysilane, vinyltriethoxysilane and (meth) acryloxypropyltrimethoxysilane; Containing silicon compounds such as 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane and N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane. ; And 3-chloropropyltrimethoxysilane, and the like, but are not limited thereto. Preferably, a silane coupling agent having an epoxy structure can be used.

The silane coupling agent may be contained in an amount of 0.1 to 10% by weight, preferably 0.1 to 5% by weight, based on the solid content of the pressure-sensitive adhesive composition. Within this range, the adhesive strength to the liquid crystal panel is excellent and the storage stability of the (meth) acrylic copolymer can be excellent.

The pressure-sensitive adhesive composition may further comprise a solvent. The solvent is not particularly limited, but methyl ethyl ketone and the like can be used.

The pressure-sensitive adhesive composition may further contain conventional additives such as an ultraviolet absorber and an antioxidant.

The pressure-sensitive adhesive composition may have a gel fraction of 50% or more, preferably 80% or more, more preferably 80-95%, expressed by the following formula (1). Within this range, the aging time can be shortened:

<Formula 1>

Gel fraction (%) = (W _C -W _A ) / (W _B -W _A ) × 100

(Where W _A is the weight of the wire mesh,

W _B is the total weight of the dried product of the pressure-sensitive adhesive composition obtained after aging of the pressure-sensitive adhesive composition at room temperature for 1 hour at 35 ° C and a relative humidity of 45%

W _C was obtained by aging the pressure-sensitive adhesive composition, and 0.5 g of the dried product of the pressure-sensitive adhesive composition was allowed to stand for 1 hour at 35 캜 and 45% relative humidity, and then placed in a wire net and placed in a sample bottle containing 50 cc of ethyl acetate. Lt; 0 &gt; C and dried for 12 hours at 100 DEG C in a wire mesh state)

The pressure-sensitive adhesive composition is prepared by drying (or aging) the pressure-sensitive adhesive composition for 1 day, measuring the gel fraction according to Formula 1 and drying (or aging) the pressure-sensitive adhesive composition for 7 days and measuring the gel fraction May be 5% or less, preferably 3% or less, more preferably 2% or less, and most preferably 0.1-2%.

The pressure-sensitive adhesive composition may be used as a pressure sensitive adhesive (PSA) material. Specifically, the pressure-sensitive adhesive composition may be used as a PSA pressure-sensitive adhesive for adhering a polarizing plate to a panel (e.g., a liquid crystal display panel). Further, the pressure-sensitive adhesive composition may also be used as a pressure-sensitive adhesive for sticking a plurality of protective films in a polarizing plate including a plurality of protective films. The pressure-sensitive adhesive composition may also be used as a pressure-sensitive adhesive for sticking a plurality of functional films in a polarizing plate including a plurality of functional films.

The polarizing plate, which is another aspect of the present invention, may comprise an adhesive layer comprising the pressure-sensitive adhesive film for a polarizing plate or the pressure-sensitive adhesive composition for a polarizing plate.

The polarizing plate may include a polarizer, a protective film, and an adhesive layer. The polarizing plate has a conventionally known structure. Generally, a protective film is laminated on both sides of a polarizer, and an adhesive layer is formed on one side of the protective film. A polarizing plate may be laminated on a substrate including a panel or the like via an adhesive layer.

The polarizer is made of a polyvinyl alcohol-based film and is not particularly limited as long as it is a polyvinyl alcohol-based film regardless of the manufacturing method. For example, a polarizer may be a modified polyvinyl alcohol film such as a partially-formalized polyvinyl alcohol film or an acetoacetyl-modified polyvinyl alcohol film.

The degree of polymerization of polyvinyl alcohol is preferably 1,500 to 4,000. Within this range, it can function as a polarizing substrate and does not deviate from its optical properties when manufactured into a polarizing film.

Polarizers are prepared by dyeing a polyvinyl alcohol film with iodine or a dichroic dye and stretching it in a certain direction. Specifically, it is produced through a swelling process, a dyeing process, and a stretching process. Methods of performing each step are commonly known to those skilled in the art.

The thickness of the polarizer is not particularly limited, but may preferably be 10 占 퐉 to 50 占 퐉.

The protective film may be laminated on one side or both sides of the polarizer. The protective film may be a polyester-based, poly (ethylene terephthalate) -based film including a cyclic olefin polymer including a cyclic olefin polymer (COP), a poly (meth) acrylate, a polycarbonate, Polyether sulfone, ether sulfone, polysulfone, polyamide, polyimide, polyolefin, polyarylate, polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride or a mixture thereof.

Preferably a cyclic polyolefin-based, polycarbonate-based, poly (meth) acrylate-based, or polyester-based.

The thickness of the protective film is not particularly limited, but may be 10 占 퐉 to 200 占 퐉, preferably 30 占 퐉 to 120 占 퐉.

The pressure-sensitive adhesive layer may be formed by drying and / or aging the pressure-sensitive adhesive composition for a polarizing plate and may be prepared by further curing. The drying and / or aging can be carried out for one week at 35 DEG C, but is not limited thereto.

The thickness of the pressure sensitive adhesive layer in the polarizing plate may be 5 占 퐉 to 100 占 퐉.

1 is a cross-sectional view of a polarizing plate of one embodiment of the present invention.

1, the polarizer comprises a polarizer 1; A first protective film (2) stacked on top of the polarizer; And a second protective film 3 stacked on the lower portion of the polarizer and stacked on a liquid crystal display panel (not shown). The second protective film 3 may be laminated on the liquid crystal display panel by the adhesive layer 4. [

2 is a cross-sectional view of a polarizing plate of another embodiment of the present invention.

2, the polarizer comprises a polarizer 1; A first protective film (2) stacked on top of the polarizer; A second protective film (3a) laminated on a lower portion of the polarizer; And a third protective film 3b laminated on the lower side of the second protective film and stacked on a liquid crystal display panel (not shown). The third protective film may be laminated between the second protective film and the liquid crystal display panel by the adhesive layers (4,5). At least one of the adhesive layers (4, 5) may be formed of the pressure sensitive adhesive for the polarizing plate.

The upper part and the lower part are not necessarily fixed to the upper and lower sides, but the upper part is changed to the lower part and the lower part is changed to the upper part depending on the viewing time of the polarizer .

In the above, at least one of the first protective film, the second protective film and the third protective film may be replaced with a retardation film having a retardation function.

The retardation film may be a retardation film conventionally known in a polarizing plate. For example, it may be a cyclic polyolefin-based, polycarbonate-based, poly (meth) acrylate-based, or polyester-based.

The polarizing plate can minimize light leakage when attached to a panel (e.g., a liquid crystal display device panel). The polarizing plate may have a light-shielding index (L) expressed by the following formula (2) of 0 to 0.4, preferably 0 to 0.1.

<Formula 2>

L = [(a + b + d + e) / 4] / c - 1

(Where a, b, d, and e are the luminance measured at the center of each side of the panel in which the polarizer is stacked after reliability injection, and c is the luminance at the center of the panel in which the polarizer is stacked after reliability injection)

Light leakage can be measured by a conventional method.

In the measurement of light leakage, the specimen may be measured after leaving 250 hours at 85 ° C. or 250 hours at 60 ° C. and 90% relative humidity, which is a wet heat resistance condition, and then leaving at 25 ° C. for 1 hour or more.

Specific methods of measurement of light leakage can be referred to the following experimental examples.

A display device according to another aspect of the present invention may include the adhesive film or the polarizer.

The display device may include, but is not limited to, a liquid crystal display device including a TFT-LCD or the like.

4 is a partial cross-sectional view of a display device according to an embodiment of the present invention.

As shown in FIG. 4, the display device includes a panel 40; And a polarizing plate 100 formed on the upper surface of the panel.

Hereinafter, the configuration and operation of the present invention will be described in more detail with reference to preferred embodiments of the present invention. It is to be understood, however, that the same is by way of illustration and example only and is not to be construed in a limiting sense.

Synthetic example  1: Preparation of monomers of formula (3)

1 L reactor was charged with 100 parts by weight of 4-hydroxypyridine (TCI), 190 parts by weight of 1-bromohexanol (TCI) and 726 parts by weight of potassium carbonate (TCI), and then dimethylformamide By weight. Nitrogen gas was poured in for 1 hour to remove oxygen, and the temperature was maintained at 100 ° C. The mixture was reacted for 24 hours with uniform stirring. The solvent was removed under reduced pressure, and 100 parts by weight of chloroform was mixed. The unmelted portion was removed by filtration, and the solvent was removed under reduced pressure. 100 parts by weight of chloroform and 50 parts by weight of triethylamine (TCI) were added. After that, nitrogen gas was introduced and replaced for 1 hour in order to remove oxygen. Then, 50 parts by weight of acryloyl chloride (TCI) was slowly added thereto, stirred and reacted for 8 hours. Then, the reaction product was washed with distilled water and 500 mL of a 1N aqueous solution of NaOH, and the solvent was removed under reduced pressure to obtain a monomer represented by the following formula (3).

(3)

Manufacturing example  One:( Meta ) Preparation of Acrylic Copolymer

98 parts by weight of n-butyl acrylate (BA), 0.5 part by weight of 2-hydroxyethyl acrylate (2-HEA), 0.5 part by weight of acrylic acid (AA ) And 1 part by weight of the monomer (PY) of Synthesis Example 1, and then 100 parts by weight of ethyl acetate (EA) was added as a solvent. After that, the reactor was replaced with nitrogen gas for 1 hour to remove oxygen, and the temperature was maintained at 62 ° C. After uniformly stirring the monomer mixture, 0.07 part by weight of azobisisobutyronitrile (AIBN) was added as a reaction initiator and reacted for 8 hours to prepare an acrylic copolymer having a weight average molecular weight of 800,000 g / mol.

Manufacturing example  2-7: ( Meta ) Preparation of acrylic copolymer

An acrylic copolymer was prepared in the same manner as in Production Example 1, except that the content of each monomer was changed to the following Table 1 (unit: parts by weight, solid basis).

division Manufacturing example One 2 3 4 5 6 7 Monomer
Furtherance n-butyl acrylate (BA) 98 94 89 69 49 99 94 2-hydroxyethyl acrylate
(2-HEA) 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Acrylic acid (AA) 0.5 0.5 0.5 0.5 0.5 0.5 0.5 The monomer containing pyridyl group (PY) One 5 10 30 50 - - Acrylamide (AAM) - - - - - - 5

Specific specifications of the components used in the following examples and comparative examples are as follows.

(A1) a copolymer of Production Example 1, (A2) a copolymer of Production Example 2, (A3) a copolymer of Production Example 3, (A4) a copolymer of Production Example 4, (A5) a copolymer of Production Example 5, (A6) a copolymer of Production Example 6, (A7) a copolymer of Production Example 7

(B) Hardener: Trimethylolpropane adduct of diisocyanate, an isocyanate-based curing agent, Coronate L (Nippon Polyurethane Industry, Japan)

(C) Silane coupling agent: 3-glycidoxypropyltrimethoxysilane (KBM-403, Shin-Etsu Chemical Co.)

Examples Comparative Example

(Meth) acrylic copolymer, a curing agent and a silane coupling agent were added to 10 parts by weight of methyl ethyl ketone in terms of the content shown in Table 2 (unit: parts by weight, solids content) and stirred at 25 ° C for 30 minutes to prepare a pressure sensitive adhesive composition.

division Example Comparative Example One 2 3 4 5 One 2 Copolymer (A1) 99 - - - - - - (A2) - 99 - - - - - (A3) - - 99 - - - - (A4) - - - 99 - - - (A5) - - - - 99 - - (A6) - - - - - 99 - (A7) - - - - - - 99 Hardener 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Silane coupling agent 0.5 0.5 0.5 0.5 0.5 0.5 0.5

The pressure-sensitive adhesive composition thus prepared and the pressure-sensitive adhesive film prepared therefrom were evaluated for the following properties.

1. Peel strength (kgf / 25 mm): 180 占 peeling force between the adhesive film and the glass substrate was measured by the method specified in JIS 2107. A sample of the pressure-sensitive adhesive composition was cut into 25 mm x 200 mm and attached to the glass surface. The adhesive layer and the glass substrate were connected to the upper and lower jig in a 30 kgf load cell using a tensile test analyzer (textureanalyzer), and then peeled off at a pulling rate of 300 mm / min. Respectively.

2. Gel fraction (%): The gel fraction was measured by measuring the gel fraction after 1 day and 7 days of aging after application by applying each composition so that the thickness after drying was 25 占 퐉 on the release film. After the application, 0.5 g of the pressure-sensitive adhesive on the support at a temperature of 35 DEG C and a humidity of 45% RH was taken and wrapped with a pre-weighed wire mesh (W _A ) so that the pressure-sensitive adhesive did not leak, (W _B ) and placed in a sample bottle. Thereafter, 50 cc of ethyl acetate was added to the sample bottle, and the sample was allowed to stand at 25 占 폚 for 1 day and dried at 100 占 폚 for 12 hours in a wire mesh state to measure the weight of the wire net containing the sample (W _C ) Fractions were determined. When the difference in gel fraction between 1 day and 7 days after aging is less than 5%, the aging is completed.

<Formula 1> Gel fraction (%) = (W _C -W _A ) / (W _B -W _A ) × 100

3. Endurance reliability: A polarizing plate (100 mm x 80 mm) coated with the pressure-sensitive adhesive composition prepared in Examples and Comparative Examples was attached to both sides of a glass substrate and a pressure of 4-5 kg / cm ² was applied to prepare a specimen. The heat resistance of the prepared specimens was evaluated by observing the occurrence of bubbles or peeling after standing at 85 ° C for 250 hours. The wet heat resistance was evaluated by observing whether bubbles or peeling occurred after standing for 250 hours at a temperature of 60 ° C and a relative humidity of 95%. The evaluation criteria are as follows.

  ◎: No bubbles or peeling at all

  ○: There are minute bubbles or peeling that can not be observed with the naked eye.

  △: There are some bubbles or peeling.

  X: There is bubble or peeling.

4. Light gauge: The pressure sensitive adhesive is coated on the polarizing plate to a thickness of 20 탆. And aged at 35 DEG C / 45% RH for 5 days to cure the pressure-sensitive adhesive. The cured samples were cut into 50 mm x 40 mm (2.5 inches) and 125 mm x 100 mm (7 inches) and laminated onto a glass substrate. The sample for measuring light leakage was laminated on both sides of the glass plate so that the light absorption axes were perpendicular to each other. To ensure good adhesion, it was held at 323 K for 1000 seconds in a vacuum autoclave. 250 hours at 80 DEG C or 250 hours at relative humidity of 60 DEG C and 90% relative humidity, and left at 25 DEG C for 1 hour or more. After driving the liquid crystal display device against the specimen, the luminance of the entire display panel was measured at a height of 1 m by using a luminance measuring device (RISA, Hiland). Specifically, the luminance (c) at the center of the panel and the luminance (a), (b), (d), and (e) of the corner where the light leakage appears are measured. As shown in FIG. 3, the luminance measurement point is located at the center of each side of the panel. The sides of the panel and the circumference of the luminance measurement circle are brought into contact with each other, and the measurement radius is 0.5 cm. In Fig. 3, a, b, c, d, e indicate brightness measurement points. The degree of light leakage (L) was quantified according to the following equation (2). The lower the L, the better the light leakage. And evaluated according to the following evaluation criteria.

<Formula 2>

L = [(a + b + d + e) / 4] / c-1

(Where a, b, d, and e are the luminance measured at the luminance measurement points a, b, d, e in FIG. 3 after reliability input, and c is the luminance at the center portion c of FIG.

?: When? L is not less than 0 and not more than 0.1

?: When ΔL is more than 0.1 and not more than 0.3

?: When? L is more than 0.3 but not more than 0.5.

×: ΔL is greater than 0.5.

division Example Comparative Example One 2 3 4 5 One 2 Evaluation items Peel strength (kgf / 25mm) 0.26 0.32 0.41 0.69 0.91 0.53 0.48 Aging 1 day Gel fraction (A) (%) 81.3 83.4 84.7 85.3 82.1 32.4 67.8 Aging 7 days Gel fraction (B) (%) 82.5 85.1 86.3 86.7 83.2 79.2 83.4 Gel fraction difference
(BA) (%) 1.2 1.7 1.6 1.4 1.1 46.8 15.6 Endurance reliability inroad ○ ○ ◎ ○ ○ △ ○ Heat resistance ○ ○ ◎ ◎ ◎ × △ Light beam ○ ○ ◎ ◎ ○ × △ Light-arm level 0.28 0.17 0.08 0.04 0.22 1.2 0.43

As shown in Table 3, the pressure-sensitive adhesive film for a polarizing plate comprising the (meth) acrylic polymer according to the present invention has a good light-shielding effect, a good durability including moisture resistance reliability and heat resistance reliability, . In addition, the pressure-sensitive adhesive composition for a polarizing plate comprising the (meth) acrylic polymer according to the present invention can obtain a sufficient aging effect even if the aging time is short.

On the other hand, the pressure-sensitive adhesive film of Comparative Example 1-2 containing no (meth) acrylic polymer according to the present invention had poor light durability and a relatively long aging time.

Claims (21)

A pressure-sensitive adhesive film for a polarizing plate comprising a cured product of a composition comprising a (meth) acrylic copolymer having a functional group represented by the following formula
&Lt; Formula 1 >

(Where * is the connecting site of the element,
X is a pyridyl group or a pyrimidinyl group,
Y is -O-, -S-, -NR-, - (C = O) NR-, -NR (C = O) - (wherein R is hydrogen or an alkyl group having 1-5 carbon atoms) C = O) -, -O (C = O) - or - (C = O)
and n is an integer of 2 to 16).
The pressure-sensitive adhesive film for a polarizing plate according to claim 1, wherein the functional group of the formula (1) is contained in the side chain of the (meth) acrylic copolymer.
The pressure-sensitive adhesive film for a polarizing plate according to claim 1, wherein the pressure-sensitive adhesive film has a 180 DEG peel strength of 0.1 to 1.0 kgf / 25 mm as measured by JIS 2107. [
The pressure-sensitive adhesive film for a polarizing plate according to claim 1, wherein the (meth) acrylic copolymer is a copolymer of a monomer mixture comprising a monomer represented by the following formula (2)
(2)

(Wherein X is a pyridyl group or a pyrimidinyl group,
Y is -O-, -S-, -NR-, - (C = O) NR-, -NR (C = O) - (wherein R is hydrogen or an alkyl group having 1-5 carbon atoms) C = O) -, -O (C = O) - or - (C = O)
n is an integer of 2 to 16,
And R < _{1 >} is hydrogen or an alkyl group having 1-5 carbon atoms.
The pressure-sensitive adhesive film for a polarizing plate according to claim 4, wherein the monomer is contained in an amount of 1-50% by weight of the (meth) acrylic copolymer.
5. The thermoplastic resin composition according to claim 4, wherein the (meth) acrylic copolymer is at least one of (meth) acrylic monomers having an alkyl group, a (meth) acrylic monomer having a hydroxy group, Adhesive film for a polarizing plate.
The method of claim 6, wherein the copolymer
1 to 50% by weight of the monomer of the formula (2)
49 to 98% by weight of the (meth) acrylic monomer having the alkyl group,
0 to 10% by weight of the (meth) acrylic monomer having a hydroxy group,
And 0-10% by weight of a (meth) acrylic monomer having a carboxylic acid group.
The adhesive film for a polarizing plate according to claim 1, wherein the composition further comprises a curing agent.
The adhesive film for a polarizing plate according to claim 8, wherein the curing agent comprises at least one of isocyanate, epoxy, aziridine, melamine, amine, imide, carbodiimide and amide.
The pressure-sensitive adhesive film for a polarizing plate according to claim 8, wherein the composition further comprises a silane coupling agent.
The pressure-sensitive adhesive film for a polarizing plate according to claim 10, wherein the silane coupling agent has an epoxy structure.
11. The composition of claim 10 wherein the composition is based on solids
93 to 99.8% by weight of the (meth) acrylic copolymer,
0.1 to 2% by weight of the curing agent,
And 0.1-5% by weight of the silane coupling agent.
A pressure-sensitive adhesive composition for a polarizing plate comprising a (meth) acrylic copolymer of a monomer mixture comprising a monomer of the following formula (2) and a curing agent:
(2)

(Wherein X is a pyridyl group or a pyrimidinyl group,
Y is -O-, -S-, -NR-, - (C = O) NR-, -NR (C = O) - (wherein R is hydrogen or an alkyl group having 1-5 carbon atoms) C = O) -, -O (C = O) - or - (C = O)
n is an integer of 2 to 16,
And R < _{1 >} is hydrogen or an alkyl group having 1-5 carbon atoms.
The copolymer according to claim 13, wherein the copolymer comprises at least one copolymer of the monomer of Formula 2 and at least one of a (meth) acrylic monomer having an alkyl group, a (meth) acrylic monomer having a hydroxy group, and a (meth) acrylic monomer having a carboxylic acid group By weight of the pressure-sensitive adhesive composition.
The pressure-sensitive adhesive composition for a polarizing plate according to claim 13, wherein the composition further comprises a silane coupling agent.
16. The composition of claim 15, wherein the composition is based on solids
93 to 99.8% by weight of the (meth) acrylic copolymer,
0.1 to 2% by weight of the curing agent,
And 0.1-5% by weight of the silane coupling agent.
14. The method according to claim 13, wherein when the gel fraction is expressed by the following formula 1, the gel fraction of the composition after aging for 1 day and measured according to the following formula 1 and the gel fraction after aging for 7 days, Sensitive adhesive composition for a polarizing plate, wherein the difference in the gel fraction is 5% or less:
<Formula 1>
Gel fraction (%) = (W _C -W _A ) / (W _B -W _A ) × 100
(Where W _A is the weight of the wire mesh,
W _B is the total weight of the dried product of the pressure-sensitive adhesive composition obtained after aging of the pressure-sensitive adhesive composition at room temperature for 1 hour at 35 ° C and a relative humidity of 45%
W _C was obtained by aging the pressure-sensitive adhesive composition, and 0.5 g of the dried product of the pressure-sensitive adhesive composition was allowed to stand for 1 hour at 35 캜 and 45% relative humidity, and then placed in a wire net and placed in a sample bottle containing 50 cc of ethyl acetate. And dried at 100 DEG C for 12 hours in a wire mesh state).
A polarizing plate comprising a polarizer, a protective film laminated on at least one side of the polarizer, and an adhesive layer laminated on one side of the protective film,
Wherein the pressure-sensitive adhesive layer comprises a cured product of a composition comprising a (meth) acrylic copolymer having a functional group of Formula 1:
&Lt; Formula 1 >

(Where * is the connecting site of the element,
X is a pyridyl group or a pyrimidinyl group,
Y is -O-, -S-, -NR-, - (C = O) NR-, -NR (C = O) - (wherein R is hydrogen or an alkyl group having 1-5 carbon atoms) C = O) -, -O (C = O) - or - (C = O)
and n is an integer of 2 to 16).
The polarizing plate according to claim 18, wherein the polarizing plate has a light-shielding index (L) of 0 to 0.4,
<Formula 2>
L = [(a + b + d + e) / 4] / c - 1
(Where a, b, d, and e are the luminance measured at the center of each side of the panel in which the polarizer is stacked after reliability injection, and c is the luminance at the center of the panel in which the polarizer is stacked after reliability injection).
The polarizing plate according to claim 18, wherein the pressure-sensitive adhesive layer is formed from the pressure-sensitive adhesive composition for a polarizing plate according to any one of claims 13 to 17.
18. A display device comprising the polarizer of claim 18.

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