KR20090013977A

KR20090013977A - Pressure sensitive adhesive composition including amine-crosslinker

Info

Publication number: KR20090013977A
Application number: KR1020070078165A
Authority: KR
Inventors: 김용연; 유정호; 최한영
Original assignee: 동우 화인켐 주식회사
Priority date: 2007-08-03
Filing date: 2007-08-03
Publication date: 2009-02-06

Abstract

The present invention relates to a pressure-sensitive adhesive composition comprising an amine-based crosslinking agent and an acrylic copolymer, and an application thereof, to a pressure-sensitive adhesive composition prepared by a crosslinking reaction using a novel reaction mechanism, a polarizing plate using the same, and a liquid crystal display device including the polarizing plate. will be.

According to the present invention, since the crosslinking reaction may proceed regardless of the functional group of the acrylic copolymer, the pressure-sensitive adhesive composition may be prepared by advancing the crosslinking reaction using an acrylic copolymer that does not include a reactive functional group in the side chain. Depending on the type of monomer used to prepare the copolymer it may be possible to express the antistatic performance without the addition of an additional antistatic agent.

Description

Adhesive composition containing an amine-type crosslinking agent {PRESSURE SENSITIVE ADHESIVE COMPOSITION INCLUDING AMINE-CROSSLINKER}

The present invention relates to an adhesive composition and its application, and more particularly to an adhesive composition comprising an amine-based crosslinking agent and an acrylic copolymer and manufactured using a novel crosslinking reaction mechanism, a polarizing plate using the same, and a liquid crystal display including the polarizing plate. Relates to a device.

The main structure for forming a liquid crystal display device is a multi-layer integrated with an adhesive layer or an adhesive layer, based on a liquid crystal cell composed of a liquid crystal layer that is constantly arranged and a transparent glass plate or plastic plate-like material including a transparent electrode layer. It is common to include polarizing plates, retardation plates, and further functional film layers, etc. of the structure. In order to manufacture such a liquid crystal display device, a liquid crystal cell containing a liquid crystal and a polarizing plate are basically required, and an appropriate adhesive layer or adhesive layer for bonding them should be used. In addition, in order to improve the function of the liquid crystal display, a retardation plate, a wide viewing angle compensation plate, or a brightness enhancement film may be additionally attached to the polarizing plate.

In the pressure-sensitive adhesive for polarizing plates used to attach such member films to polarizing plates, durability is most important as the required physical properties, and the durability depends on the crosslinking reaction of the pressure-sensitive adhesive polymer and the crosslinking agent.

The crosslinking agent used to crosslink the polymers can be broadly divided into isocyanate-based, epoxy-based, and aziridine-based. Among them, the crosslinking agent most frequently used is a substance containing two or more isocyanate functional groups such as trimethylolpropantolylene isocyanate, and the substance is an alcohol functional group, an acid functional group or an amide functional group of the polymer by a reaction mechanism as shown in Scheme 1 below. And polymers are reacted with each other [Japanese Patent Laid-Open Publication 07-155637, Japanese Patent Laid-Open Publication 08-024832, Japanese Patent Laid-Open Publication 08-166628, Japanese Patent Laid-Open Publication 08-220700, Japanese Patent Laid-Open Publication 08-220701] . Therefore, in order to use isocyanate as a crosslinking agent, it is necessary to use a polymer containing a functional group capable of reacting with an isocyanate such as a hydroxyl group, a carboxyl group or an amide group.

In addition, in the case of an isocyanate crosslinking agent, an excess isocyanate functional group reacts with water to generate carbon dioxide, which may cause a lifting phenomenon of the adhesive and the adhesive.

The second most commonly used crosslinking agent is a material containing two or more epoxy groups, which connect the polymers by a reaction mechanism such as the following Scheme 2 (X = O). Thus, when using an epoxy crosslinking agent, the polymer which generally contains a carboxy group must be used as a functional group [Japanese Laid-Open Patent Publication 07-028823, Japanese Laid-Open Patent Publication 07-028825, Japanese Laid-Open Patent Publication 08-028827, Japan Japanese Patent Application Laid-Open No. 08-028831, Japanese Laid-Open Patent Publication 08-028821]. These epoxy crosslinkers may also be used in admixture with isocyanate crosslinkers.

Finally, an aziridine crosslinking agent is used as a crosslinking agent of an adhesive composition. Scheme 2 (X = NH) shows the reaction mechanism of the aziridine crosslinker and the polymer. The aziridine crosslinking agent has a relatively high crosslinking rate compared to the epoxy group or the isocyanate group, but has a problem of poor storage stability and high price [Japanese Patent Publication 2003-125145, Japanese Patent Publication 2002-148670, Japanese Patent Publication 2002-148673, Japan JP 2003-098425].

The crosslinking reaction by the above crosslinking agents influences the percentage of the gel fraction which has a significant influence on the physical properties of the pressure sensitive adhesive.

On the other hand, in the pressure-sensitive adhesive for polarizing plate, there is an antistatic performance with additionally required physical properties. This will be described in detail below.

In the manufacturing of the liquid crystal display device, in the process of attaching the polarizing plate to the liquid crystal cell, peeling the release film from the pressure-sensitive adhesive layer generates static electricity. The generated static electricity affects the alignment of the liquid crystal inside the liquid crystal display device and is thus defective. It causes the contamination by foreign matter between the liquid crystal cell and the adhesive by the electrostatic attraction.

In order to solve the problems caused by static electricity generation, generally in forming an adhesive layer on a protective film, a method using a conductive adhesive with an antistatic agent added to the adhesive, an antistatic layer by applying an antistatic agent between the polarizing plate and the adhesive layer As the method for forming the polymer and the polymer added as the pressure-sensitive adhesive composition, a method using an ionic acrylate copolymer is used.

Hereinafter, the method of providing antistatic property to a polarizing plate is explained in full detail.

First, a method of imparting antistatic property by adding an antistatic agent to the pressure-sensitive adhesive layer is a method of adding a material having a conductive component such as conductive polymer, metal oxide particles, or carbon particles, ionic material such as metal salt or surfactant Is added to the pressure-sensitive adhesive (Korean Patent Publication No. 10-1998-0081608, Korean Patent Publication No. 10-1989-00133673, Korean Patent Publication No. 10-2001-0111715, Korean Patent Publication Korean Patent Publication No. 10-2004-0032058, Korean Patent Publication No. 10-2006-0018495, Korean Patent Publication No. 10-2004-0030919, Korean Patent Publication No. 10-2001-0010433, Korean Patent Publication 10-2005-0072576, Japanese Patent Laid-Open No. 2006-111856, Japanese Patent Laid-Open No. 2006-111846, and Japanese Patent Laid-Open No. 2006-104434).

However, when the conductive polymer, the metal oxide or the carbon particles are added, a large amount must be added in order to impart antistatic property, thereby reducing transparency. In addition, the addition of the surfactant is susceptible to humidity, and has the disadvantage of lowering the adhesive properties by the transfer to the pressure-sensitive adhesive surface. As another method, there have been attempts to add ethylene oxide-modified dioctyl phthalate plasticizer to the inside of the pressure-sensitive adhesive to provide flexibility and to suppress static electricity generation. However, the addition of such a plasticizer alone is not only difficult to suppress the generation of static electricity generated initially, it is also difficult to dissipate the static electricity remaining after peeling off the release film.

Secondly, as the method of forming an antistatic layer by applying an antistatic agent between the polarizing plate and the pressure-sensitive adhesive layer, a method of depositing an electrically conductive metal powder or metal oxide, a method of coating a conductive polymer, or the like is used. However, such a method requires an additional step of stacking an antistatic layer in imparting antistatic performance to a polarizing plate having a multilayer structure, and thus, there is a problem that the process becomes complicated and causes an increase in unit cost (Korean Patent Publication No. 10). -1997-7002906, Korean Patent Publication No. 10-2005-0036310, Japanese Patent Publication No. 2006-095875, Japanese Patent Publication No. 2006-095874, Japanese Patent Publication No. 2006-076251, Japanese Patent Japanese Patent Laid-Open No. 2005-271573, Japanese Patent Laid-Open No. 2005-238651, Japanese Patent Laid-Open No. 2005-200607, Japanese Patent Laid-Open No. 11-091038, Japanese Patent Laid-Open No. 04-304921, Japanese Patent Laid-Open 10-114886).

Third, in addition to the above two methods, no additional coating process is required, and as a method for preventing the antistatic agent from bleeding out from the pressure-sensitive adhesive, a method of immobilizing an ionic material on the polymer as the pressure-sensitive adhesive composition has been proposed. In detail, Korean Patent Publication No. 10-2001-0111715 prepares a polymer containing an epoxy group, introduces a quaternary ammonium salt by adding a tertiary amine to an epoxy group, and a polymer containing a tertiary amine. A method of preparing a quaternary ammonium salt was prepared by reacting dimethyl sulfate with a tertiary amine. However, when an excessive amount of an epoxy group or a tertiary amine is introduced into the polymer in order to exhibit sufficient antistatic properties, there is a possibility that the physical properties inherent in the pressure-sensitive adhesive may be impaired.

The antistatic properties obtained from the above methods are known as surface resistivity measurement method, saturation charge voltage measurement method, half-life measurement method of saturation charge, etc., but the most commonly used method is surface resistivity measurement method.

In order to solve the above-mentioned limitations and problems of the prior art, that is, the limitation of the selection range of the crosslinking agent and the problems of the antistatic treatment method, as a result of the study, the present inventors have used an amine crosslinking agent that reacts with an ester group as a new crosslinking agent. In this case, even when using an acrylic copolymer containing no reactive functional groups in the side chain by a novel crosslinking reaction mechanism, it is possible to proceed with the crosslinking reaction to prepare the pressure-sensitive adhesive composition, and the type of monomer used to prepare the acrylic copolymer. It was found that by controlling the expression of the antistatic performance is possible without the addition of an additional antistatic agent.

Accordingly, an object of the present invention is to provide a pressure-sensitive adhesive composition capable of advancing a crosslinking reaction regardless of a functional group of an adhesive polymer using an amine-based crosslinking agent and expressing antistatic performance without the addition of an additional antistatic agent. .

In addition, an object of the present invention is to provide a polarizing plate and a liquid crystal display device using the pressure-sensitive adhesive composition.

In order to achieve the above object, an aspect of the present invention is an acrylic air having a) an amine crosslinking agent having at least two amine functional groups in a molecule and b) an ester group capable of reacting with the a) amine crosslinking agent to form an amide. Provided is an adhesive composition comprising coalescing.

According to one embodiment, the b) acrylic copolymer is obtained by copolymerizing a (meth) acrylic acid ester monomer for preparing a homopolymer having a glass transition temperature of -70 ℃ ~ 10 ℃ and optionally an acrylic monomer having a functional group.

According to another embodiment, the acrylic monomer having a functional group includes a (meth) acrylate monomer including a carboxyl group or a hydroxy group.

According to another embodiment, the acrylic monomer having a functional group includes a (meth) acrylate monomer including a hydroxy group.

According to another embodiment, when the acrylic monomer having the functional group is included in b) the acrylic copolymer, the content thereof is 0.3 to 25 parts by weight based on 100 parts by weight of the acrylic copolymer.

According to another embodiment, the amine crosslinking agent having two or more amine functional groups in the molecule is an amine crosslinking agent having an ether group in the molecule.

According to another embodiment, the amine crosslinking agent having two or more amine functional groups in the molecule, b) 0.1 to 10 parts by weight based on 100 parts by weight of the acrylic copolymer.

The second aspect of the present invention provides a polarizing plate including a pressure-sensitive adhesive layer formed using the pressure-sensitive adhesive composition.

A third aspect of the present invention provides a liquid crystal display device including the polarizing plate.

The present invention relates to a pressure-sensitive adhesive composition comprising an amine-based crosslinking agent and an acrylic copolymer, and to a pressure-sensitive adhesive prepared by a crosslinking reaction using a novel reactive mechanism. Since the crosslinking reaction may proceed regardless of the functional group of the acrylic copolymer, a reactive functional group may be used. The copolymer which does not contain can be used to advance the crosslinking reaction, and it can also be possible to express the antistatic performance without the addition of an additional antistatic agent.

Hereinafter, the configuration and operation of the present invention will be described in detail.

The amine crosslinking agent and the acrylic copolymer used in the present invention can be used as long as the amine crosslinking agent and the acrylic copolymer can show the formation of crosslinking by the amide bond by the reaction between the amines and the esters below.

This will be described in detail below.

In the above Reaction Scheme 3, R can be anything that corresponds to the acrylic copolymer of the present invention described below, specifically, an alkyl group having 1 to 20 carbon atoms with or without hydrogen or a reactive functional group.

R ₁ and R ₂ may each independently be anything other than an electrophilic substituent such as an aryl or an acyl group which deactivates the nucleophilic substitution reaction of an amine, but preferably includes 1 to 3 carbon atoms, including or without hydrogen or heteroatoms. It is an alkyl group of 12, More preferably, it is hydrogen.

The b) acrylic copolymer of the present invention is a copolymer having an ester group capable of reacting with an amine crosslinking agent to form an amide. The acrylic copolymer can be used as long as it corresponds to an acrylic copolymer containing an ester group, regardless of the presence or absence of a reactive functional group, and preferably has a glass transition temperature of -70 ° C to 10 ° C. It is preferable that it is an acrylic copolymer obtained by copolymerizing the (meth) acrylic acid ester monomer for homopolymer manufacture, and the acryl-type monomer which optionally has a functional group.

That is, the pressure-sensitive adhesive composition of the present invention is a (meth) acrylic acid ester monomer for producing a homopolymer having a glass transition temperature of -70 ° C to 10 ° C and an acrylic monomer having a functional group are copolymerized to form an acrylic copolymer having a reactive functional group in the side chain. The pressure-sensitive adhesive may be prepared, but the pressure-sensitive adhesive may be prepared using an acrylic copolymer which is copolymerized only with the (meth) acrylic acid ester monomer for preparing a homopolymer having a glass transition temperature of -70 ° C to 10 ° C and does not contain a reactive functional group. can do.

The (meth) acrylic acid ester monomer for producing a homopolymer having a glass transition temperature of -70 ° C to 10 ° C enhances cohesive force by adjusting the weight part (content) of the reactive functional group in the polymer to improve adhesive durability and cutability. On the contrary, stress relaxation characteristics can be improved. Preferably, it is advantageous to use a (meth) acrylic acid ester monomer for producing homopolymers having a glass transition temperature of -60 ° C to -10 ° C.

At this time, in this invention, "(meth) acryl" is the concept containing methacryl and acryl.

Examples of the (meth) acrylic acid ester monomer for preparing a homopolymer having a glass transition temperature of -70 ° C to 10 ° C include n-octyl acrylate, 2-ethylhexyl acrylate, 2-ethylbutyl acrylate, hexyl acrylate and heptyl acryl Laten, nonyl acrylate, pentyl acrylate, isooctyl acrylate, n-decyl methacrylate, n-dodecyl methacrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, ethyl acrylate, methyl Acrylate, 3-methylbutyl acrylate, n-hexyl methacrylate, n-octyl methacrylate, n-tetradecyl methacrylate, and the like. These monomers may be used alone or in combination of two or more thereof.

Moreover, as the acryl-type monomer which has the said functional group, the (meth) acrylate type monomer which has arbitrary functional groups, such as a hydroxyl group, a carboxy group, and an amide functional group, can be used.

In the present invention, by controlling the type of the acrylic monomer having the functional group it can be possible to express the antistatic performance without the addition of an additional antistatic agent. For example, when the acrylic monomer having a functional group is acrylic acid containing a carboxyl group, it may form a salt with an amine crosslinking agent, so that the antistatic performance may be weakened and the crosslinking reaction rate may be slowed. Therefore, in order to raise the antistatic performance of an adhesive without adding an antistatic agent, monomers other than the acrylic acid monomer (for example, acrylic acid, methacrylic acid etc.) which have a carboxyl group as an acrylic monomer which has a functional group are preferable.

More preferably, it is preferable to use a (meth) acrylate monomer containing a hydroxy group which has a high crosslinking reaction rate and which does not cause a problem in antistatic performance, and these may be used alone or in combination of two or more thereof. As a (meth) acrylate monomer containing the said hydroxy, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxyethylene glycol (meth) acrylate , 2-hydroxypropylene glycol (meth) acrylate, and the like, and these can be used alone or in combination of two or more thereof.

When the acrylic monomer having the functional group is included in the acrylic copolymer of the present invention, the content thereof is preferably 0.3 to 25 parts by weight based on 100 parts by weight of the acrylic copolymer. When the content of the monomer having a functional group is less than 0.3 parts by weight, the cohesion force becomes small due to insufficient crosslinking degree, resulting in deterioration of adhesive durability and cleavage properties, and in the case of more than 25 parts by weight, the residual stress is reduced by excessive crosslinking reaction. A problem arises.

In addition to the present invention, all of the vinyl monomers including a hydroxyl group or an imide group may be used. The aforementioned components can be used alone or in combination if necessary.

In the present invention, an acrylic copolymer may be prepared by copolymerizing monomers of the above composition, and the molecular weight of the acrylic copolymer is preferably in the range of 200,000 to 2,500,000 in molecular weight in consideration of adhesive properties and coating properties. The method for producing the acrylic copolymer is not particularly limited, and may be prepared by solution polymerization, photopolymerization, bulk polymerization, suspension polymerization or emulsion polymerization. Preferably, the acrylic copolymer is prepared using a solution polymerization method, the polymerization temperature is preferably 50 ~ 110 ℃, it is preferable to add the initiator in a state where the monomers are uniformly mixed.

In the pressure-sensitive adhesive composition of the present invention, the a) amine-based crosslinking agent serves to increase the cohesive force of the pressure-sensitive adhesive by reacting with the ester group which is the main skeleton of the polymer.

As the amine-based crosslinking agent, any compound having two or more primary or secondary amine groups capable of reacting with an ester of a polymer in a molecule may be used. Specifically, ethylene glycol bis (3-aminopropyl) ether, Diethylene glycol bis (3-aminopropyl) ether, bis (3-aminopropyl) ether, 1,4-bis (3-aminopropyl) piperazine, ethylenediamine, 1,3-diaminopropane, 1,2- Diaminopropane, 1,4-diaminobutane, 1,2-diamino-2-methylpropane, 1,5-diaminopentane, 2,2-dimethyl-1,3-propanediamine, hexamethylenediamine, 1 , 7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,12-diaminododecane, diethylenetriamine, N- (2 -Aminoethyl) -1,3-propanediamine, N- (3-aminopropyl) -1,3propanediamine, spermidine, bis (hexamethylene) triamine, 4- (aminomethyl) -1,8- Octanediamine, Trie Lentetramine, N, N-bis (2-aminoethyl) -1,3-propanediamine, spermine, tris (2-aminoethyl) amine, pentaethylenehexamine, 4,4'-methylenebis (cyclo Hexylamine), cis1,2-diaminocyclohexane, trans1,2-diaminocyclohexane, cis1,4-diaminocyclohexane, trans1,4-diaminocyclohexane, 1,3- Cyclohexanebis (methylamine), 1,8-diamino-paramethane, 5-amino-1,3,3-trimethylcyclohexanemethylamine, 2,2 '-(ethylenedioxy) -bis (ethylamine ), 4,7,10-trioxa-1,13-tritecandiamine, 1,3-diamino-2-hydroxypropane and the like.

The amine crosslinking agent is preferably selected in consideration of compatibility and crosslinking reactivity. An amine crosslinking agent having an ether group in a molecule is preferable in view of compatibility with a polymer solution. For example, ethylene glycol bis (3-aminopropyl) ether, diethylene glycol bis (3-aminopropyl) ether, bis (3-aminopropyl) ether, 1,4-bis (3-aminopropyl) piperazine Etc.

The content of such a crosslinking agent is preferably used in an amount of 0.1 to 10 parts by weight, and more preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the acrylic copolymer of a). When the content of the amine-based crosslinking agent exceeds 10 parts by weight, a problem may be expected in relaxation of residual stress due to an excessive crosslinking reaction, and when the content of the amine crosslinking agent is less than 0.1 part by weight, the cohesive force may be reduced due to insufficient crosslinking degree, thereby impairing adhesive durability and cutting property I'm concerned about the results.

Furthermore, c) silane coupling agent can be further added to the adhesive composition of this invention. As the silane coupling agent, a known coupling agent can be used without limitation, but a silane coupling agent containing an epoxy group is preferably used.

The silane coupling agent containing the epoxy group serves to connect the pressure-sensitive adhesive and the liquid crystal cell. The epoxy group in the molecule is bonded to the reactive functional group or the crosslinking agent of the polymer, and the alkoxysilane portion is strongly bonded to the glass substrate of the liquid crystal cell, thereby ensuring adhesion stability. By improving the heat and moisture resistance characteristics, the silane coupling agent serves to improve the adhesion reliability, especially when left for a long time under high temperature and high humidity. As an example, gamma glycidoxy propyl trimethoxysilane can be mentioned.

The content of the silane coupling agent is preferably used in an amount of 0.01 to 1 part by weight based on 100 parts by weight of the acrylic copolymer.

When considering the optimal physical balance of the pressure-sensitive adhesive composition according to the present invention, the crosslinking density of the pressure-sensitive adhesive may have a range of 5 to 100%, preferably 60 to 95%. The above-mentioned crosslinking density can be obtained by weight% of the part which formed the crosslinked structure which is not dissolved in a solvent through the gel content measurement method of the acrylic adhesive generally known.

In addition, the present invention may further add a tackifying resin in order to adjust the adhesive performance, the content thereof may be used in the range of 1 to 100 parts by weight based on b) 100 parts by weight of the acrylic copolymer. At this time, if the tackifying resin is used in excess, the compatibility or cohesion of the pressure-sensitive adhesive may be reduced, so it should be added appropriately with caution.

Examples of the tackifying resins include (hydrogenated) hydrocarbon resins, (hydrogenated) rosin resins, (hydrogenated) rosin ester resins, (hydrogenated) terpene resins, (hydrogenated) terpene phenol resins, polymerized rosin resins, and polymerized rosin Ester resin etc. are mentioned, These can be used individually or in mixture of 2 or more types.

On the other hand, the pressure-sensitive adhesive composition of the present invention can express the antistatic performance without the addition of a separate antistatic agent, it may be added an additional antistatic agent to further improve the antistatic performance. Additional antistatic agents may include inorganic salts such as alkali metal salts, organic salts including ammonium ions, sulfonium, phosphonium, and the like.

In addition to the present invention, a plasticizer, a curing agent, or the like may be further mixed and used for a specific purpose, and an ultraviolet stabilizer, an antioxidant, a colorant, a reinforcing agent, a filler, or the like may be appropriately added according to a general purpose.

In addition, the present invention provides a polarizing plate comprising the pressure-sensitive adhesive composition as an adhesive layer of the polarizing plate.

The polarizing plate of the present invention includes a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition on one or both surfaces on the protective film laminated on the outer surface of the polarizing film, and the polarizing film (polarizing element) constituting the polarizing plate is not particularly limited.

Preferably, examples of the polarizing film include a film obtained by containing a polarizing component such as iodine or a dichroic dye in a polyvinyl alcohol-based film and stretching the film, and the thickness of these polarizing films is also particularly limited. It is not possible to form a conventional thickness. At this time, the polyvinyl alcohol-based resin may be polyvinyl alcohol, polyvinyl formal, polyvinyl acetal and ethylene, saponified vinyl acetate copolymer.

On both sides of the polarizing film, a cellulose-based film such as triacetyl cellulose, a polycarbonate film, a polyester-based film such as polyethylene terephthalate, a polyether sulfone-based film, a polyethylene, a polypropylene, a cyclo-based or a polyolefin-based having a norbornene structure And a multilayer film in which protective films such as polyolefins such as ethylene propylene copolymer are laminated. At this time, the thickness of these protective films is also not particularly limited, and may form a conventional thickness.

In the present invention, the method of forming the pressure-sensitive adhesive layer on the polarizing plate is not particularly limited, and the method of applying and drying the pressure-sensitive adhesive using a bar coater or the like directly on the surface of the polarizing plate, or applying the pressure-sensitive adhesive on the surface of the peelable substrate once and drying The method of transferring the adhesive layer formed on the surface of this peelable base material to the surface of a polarizing plate, and then aging can be applied.

In addition, the polarizing plate of the present invention may be laminated with one or more layers that provide additional functions such as a protective layer, a reflective layer, an antiglare layer, a retardation plate, a wide viewing angle compensation film, and a brightness enhancement film.

The polarizing plate to which the pressure-sensitive adhesive of the present invention is applied can be applied to all conventional liquid crystal display devices, and the kind of the liquid crystal panel is not particularly limited. Preferably, the present invention may comprise a liquid crystal display device including a liquid crystal panel in which a polarizing plate including the pressure-sensitive adhesive is bonded to one side or both sides of a liquid crystal cell.

As described above, the pressure-sensitive adhesive composition of the present invention is completed by the cross-linking reaction using a novel reaction mechanism, regardless of the side chain functional group of the polymer for pressure-sensitive adhesive, the antistatic performance can be expressed without the addition of an additional antistatic agent, industrial Very useful.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the scope of the present invention is not limited by the Examples.

<Production of Acrylic Copolymer>

[ Production Example One]

N-butyl acrylate (BA) 99 parts by weight, 1 part by weight of acrylic acid (AA) and 100 parts by weight of ethyl acetate were added to a 1 L reactor equipped with a refrigeration system to allow nitrogen gas to reflux and to facilitate temperature control. After purging with nitrogen gas for 60 minutes to remove oxygen, the temperature was maintained at 60 ° C., and 0.03 parts by weight of azobisisobutyronitrile (AIBN), a reaction initiator, was diluted with 25% of ethyl acetate and added thereto for 8 hours. The mixture was reacted for a while, ethyl acetate was added to dilute to 15% of a solid content concentration, and diluted. A final acrylic copolymer was prepared to obtain a copolymer solution having a weight average molecular weight of 1,370,000 (polystyrene equivalent).

[ Production Example 2]

It proceeded in the same manner as in Production Example 1 using 97 parts by weight of n-butyl acrylate (BA) and 3 parts by weight of acrylic acid (AA) to obtain a copolymer polymer solution having a weight average molecular weight of 1.79 million (polystyrene equivalent).

[ Production Example 3]

Proceed in the same manner as in Preparation Example 1 using 99 parts by weight of n-butyl acrylate (BA) and 1 part by weight of 2-hydroxyethyl acrylate (2-HEA), and a copolymer having a weight average molecular weight of 1.141 million (polystyrene equivalent). A polymer solution was obtained.

[ Production Example 4]

97 parts by weight of n-butyl acrylate (BA) and 3 parts by weight of 2-hydroxyethyl acrylate (2-HEA) were carried out in the same manner as in Production Example 1 to obtain a copolymer having a weight average molecular weight of 1,370,000 (polystyrene equivalent). A polymer solution was obtained.

[ Production Example 5]

It proceeded in the same manner as in Production Example 1 using 100 parts by weight of n-butyl acrylate (BA) to obtain a copolymer polymer solution having a weight average molecular weight of 1,370,000 (polystyrene equivalent).

[ Production Example 6]

97 parts by weight of n-butyl acrylate (BA) and 3 parts by weight of methyl methacrylate (MMA) were carried out in the same manner as in Production Example 1 to obtain a copolymer solution having a weight average molecular weight of 1,250,000 (polystyrene equivalent).

[ Example One]

2 parts by weight of diethylene glycol bis (3-aminopropyl) ether as a crosslinking agent and 0.2 parts by weight of Shin-Etsu Co., Ltd. (X-41-1805) as a silane coupling agent were added to 100 parts by weight of the acrylic copolymer obtained in Production Example 1. After stirring for 2 minutes, the coating was applied on two PET films (25cm X 20cm X 38mm) coated with a release agent by using an applicator, and then coated to have a thickness of 25 microns after drying in a forced circulation hot air dryer in an oven at 100 ° C. After drying for 3 minutes, one sheet was laminated by laminating another layer of release film on the pressure-sensitive adhesive layer to obtain a pressure-sensitive adhesive layer in the form of NCF (non-carrier film), thermo-hygrostat (60%, 25 ℃) for gel fraction analysis The other sheet was attached to an iodine polarizer made of TAC (triacetylcellulose) film and PVA (polyvinyl alcohol), and evaluated for antistatic property after 14 days of curing.

[ Example 2]

It progressed like Example 1 using the acryl-type copolymer obtained by the manufacture example 2.

[ Example 3]

It proceeded similarly to Example 1 using the acryl-type copolymer obtained by the manufacture example 3.

[ Example 4]

It progressed like Example 1 using the acryl-type copolymer obtained by the manufacture example 4.

[ Example 5]

It progressed like Example 1 using the acryl-type copolymer obtained by the manufacture example 5.

[ Example 6]

It proceeded similarly to Example 1 using the acryl-type copolymer obtained in manufacture example 6.

[ Example 7]

It proceeded like Example 1 using 5 weight part of diethylene glycol bis (3-aminopropyl) ether.

[ Example 8]

It proceeded similarly to Example 1 using 1 weight part of diethylene glycol bis (3-aminopropyl) ethers.

[ Example 9]

It proceeded similarly to Example 1 using 0.5 weight part of diethylene glycol bis (3-aminopropyl) ethers.

[ Example 10]

It proceeded like Example 1 using 10 weight part of diethylene glycol bis (3-aminopropyl) ether.

[ Example 11]

It proceeded similarly to Example 1 using 0.1 weight part of diethylene glycol bis (3-aminopropyl) ether.

[ Example 12]

It proceeded like Example 1 using 2 weight part of tris (2-aminoethyl) amines.

[ Example 13]

It proceeded similarly to Example 1 using 2 weight part of ethylene glycol bis (3-aminopropyl) ether.

[ Example 14]

It proceeded similarly to Example 1 using 2 weight part of bis (3-aminopropyl) ether.

[ Example 15]

It proceeded similarly to Example 1 using 2 weight part of 1, 4-bis (3-aminopropyl) piperazine.

[ Comparative example One]

It proceeded in the same manner as in Example 4 using Coronate-L (2%) (manufactured by Nippon Urethane) by weight as a crosslinking agent.

<Evaluation test>

NCF Of type adhesive Gel %analysis

Measured by cutting the cured NCF to the appropriate size after the preparation, and immersed in ethyl acetate solvent and stored at room temperature for 48 hours, dried for 2 hours in a 60 ℃ vacuum oven, the difference in weight is measured, the difference From the gel fraction was measured.

Surface resistivity measurement method

Measuring instrument: Surface resistivity measuring instrument (MCP-HT450 / MITSUBISHI CHEMICAL), probe bar (URS, UR100), probe bar measuring instrument (URS, for UR 100)

-Measuring method: Measure the three places of the surface 10 times and take the average value.

Compatibility Evaluation

After adding the amine crosslinking agent to the polymer solution of the pressure-sensitive adhesive at room temperature and stirring for 10 minutes, after stopping the stirring for 10 minutes, the mixed state is visually observed.

(Circle): No delamination is seen and a transparent mixture is confirmed.

(Triangle | delta): Although a layer separation is not seen, a solution shows a haze in white.

X: It shows phase separation with a polymer solution.

* AA: acrylic acid, BA: butyl acrylate, 2-HEA: 2-hydroxyethyl acrylate, MMA: methyl methacrylate, GMA: glycidyl methacrylate, TTDA: diethylene glycol bis (3-aminopropyl ) Ether, TAEA: tris (2-aminoethyl) amine, EGBAPE: ethylene glycol bis (3-aminopropyl) ether, BAPE: bis (3-aminopropyl) ether, BAPP: 1,4-bis (3-aminopropyl Piperazine

From the results of Table 1, the pressure-sensitive adhesive composition of the present invention is the same or better than the pressure-sensitive adhesive composition prepared using a conventional crosslinking agent regardless of the presence and type of functional groups of the acrylic copolymer by the crosslinking reaction using a novel reaction mechanism It can be seen that the adhesive performance is expressed. In particular, in the case of using the acrylic copolymer prepared by using a monomer having a functional group other than the carboxyl group, it was confirmed that it exhibits antistatic properties that can be practical without including an antistatic agent. In addition, in the case of Examples 5 and 6 using the acrylic copolymer prepared using a monomer having no functional group, it was confirmed that the present invention exhibits practical antistatic properties without containing an antistatic agent.

Claims

a) an amine crosslinking agent having at least two amine functional groups in the molecule, and

b) an acrylic copolymer having an ester group capable of reacting with the amine crosslinking agent to form an amide

Pressure-sensitive adhesive composition comprising a.

The method according to claim 1,

The adhesive composition according to claim b, wherein the acrylic copolymer is obtained by copolymerizing a (meth) acrylic acid ester monomer for preparing a homopolymer having a glass transition temperature of -70 ° C to 10 ° C and an acrylic monomer having a functional group.

The method according to claim 2,

Adhesive composition characterized by the above-mentioned acrylic monomer which has a functional group contains the (meth) acrylate monomer containing a carboxy group or a hydroxyl group.

The method according to claim 2,

Adhesive composition characterized by the above-mentioned acrylic monomer which has a functional group contains the (meth) acrylate monomer containing a hydroxyl group.

The method according to claim 2,

When the acrylic monomer having the functional group is contained in b) the acrylic copolymer, the content thereof is 0.3 to 25 parts by weight based on 100 parts by weight of the acrylic copolymer.

The method according to claim 1,

Said a) amine type crosslinking agent which has two or more amine functional groups in a molecule | numerator is an amine type crosslinking agent which has an ether group in a molecule | numerator, The adhesive composition characterized by the above-mentioned.

The method according to claim 1,

The amine-based crosslinking agent having two or more amine functional groups in the molecule, b) 0.1 to 10 parts by weight based on 100 parts by weight of the acrylic copolymer.

The polarizing plate containing the adhesive layer formed using the adhesive composition of any one of Claims 1-7.

Liquid crystal display comprising the polarizing plate of claim 8.