KR20100058429A - Acrylic pressure sensitive adhesive compositions - Google Patents

Abstract

PURPOSE: An acrylic pressure-sensitive adhesive composition is provided to improve the basic properties of an acrylic adhesive composition including an antistatic property, optical transmittance rate, and an adhesive property. CONSTITUTION: An acrylic pressure-sensitive adhesive composition for a polarizer contains the following: 100 parts of acrylic copolymer by weight; 0.001~25 parts of metal salt by weight formed with a negative ion, including a perfluoroalkyl group and an alkali metal positive ion and marked with chemical formula: M^+[X(YO_mR_f)_n]^-; and 0.01~10 parts of polyfunctional cross-linking agent by weight. In the chemical formula, M is an alkali metal. The R_f is a perfluoroalkyl group with the carbon number of 1~4.

Description

Acrylic adhesive composition {ACRYLIC PRESSURE SENSITIVE ADHESIVE COMPOSITIONS}

The present invention relates to an acrylic pressure-sensitive adhesive composition, and more particularly, to an acrylic pressure-sensitive adhesive composition without deterioration under moisture and heat conditions without deterioration of basic physical properties of acrylic pressure-sensitive adhesives such as antistatic, light transmittance, adhesiveness, and durability. .

In general, acrylic adhesive compositions are widely applied in various fields such as industrial sheets, optical adhesives, and adhesives for electronic components, and among them, liquid crystal display devices to which optical adhesives are applied are replaced with CRTs because they can be reduced in weight and thickness. It is widely used in laptops, monitors, and TVs.

The liquid crystal display device is composed of a liquid crystal cell containing a liquid crystal, a polarizing plate, and an adhesive or adhesive layer for bonding them. The flat plate is composed of a multilayer of an iodine-based compound or a dichroic polarizing material arranged in a predetermined direction, a triacetyl cellulose (TAC) -based protective film, an adhesive layer, a release film, and the like for protecting these polarizing elements. .

In the manufacturing of the liquid crystal display device, the static electricity generated when the release film is peeled off from the adhesive layer to attach the polarizing plate to the liquid crystal cell affects the liquid crystal alignment inside the liquid crystal display device and causes defects. A method of forming an antistatic layer on the outer surface of the polarizing plate was used, but this was not the original prevention of the generation of static electricity, the effect was also very low.

Therefore, the antistatic function of the pressure-sensitive adhesive is necessary to block the generation of static electricity.

In order to give an antistatic function to an adhesive, there exist a method of adding a substance, such as a conductive metal powder and carbon particle, and the method of adding an ionic substance, such as surfactant, to an adhesive agent. However, when the conductive metal powder or the carbon particles are added, a large amount of the conductive metal powder or the carbon particles should be used in order to exhibit antistatic properties, and thus there is a problem in that transparency is lowered. In addition, when the surfactant is added, it is easy to be influenced by humidity, and there is a problem in that adhesiveness decreases with the transition to the pressure-sensitive adhesive surface.

Japanese Patent Laid-Open No. 6-128539 discloses an antistatic acrylic pressure-sensitive adhesive containing a polyether polyol compound and at least one alkali metal salt. However, in the prior art, when the isocyanate is used as the crosslinking agent, since the polyether polyol compound has a great influence on the degree of crosslinking, crosslinking with the isocyanate before dissolving the polyether polyol compound and the alkali metal salt must be dissolved again. In addition to being difficult to apply to the process, when the alkali metal salt is added, there is a problem that the transparency is reduced in the heat and humidity conditions.

Japanese Laid-Open Patent Publication No. 2005-31282 discloses a resin composition film for an optical device having an antistatic function using a metal salt containing lithium ions and a hydrophilic monomer having ethylene oxide as the resin composition. The prior art has the advantage that the lithium ion-containing metal salt provides conductivity, and the hydrophilic monomer absorbs moisture in the air to lower the generation of electrostatic charges and does not cause whitening due to haze, which is a poor appearance even in a high temperature and high humidity environment. When using a hydrophilic monomer having an ethylene oxide enough to absorb the moisture in the air to reduce the generation of electrostatic charges, there is a problem that the physical properties of the pressure-sensitive adhesive, particularly adhesion and durability reliability is sharply lowered.

Therefore, there is a need for further research on an adhesive having excellent antistatic performance and no whitening phenomenon under moisture and heat conditions without changing physical properties of an acrylic adhesive such as durability.

In order to solve the problems of the prior art as described above, the present invention provides an acrylic pressure-sensitive adhesive composition without anti-whitening under moisture and heat conditions at the same time without deterioration of the basic physical properties of the acrylic pressure-sensitive adhesive, such as antistatic, light transmittance, adhesiveness, durability For the purpose of

Another object of the present invention is to provide a polarizing plate and a liquid crystal display device to which the acrylic pressure-sensitive adhesive composition is applied, which has excellent durability and no whitening under moisture and heat conditions.

In order to achieve the above object, the present invention is an acrylic pressure-sensitive adhesive composition,

a) 100 parts by weight of the acrylic copolymer;

b) 0.001 to 25 parts by weight of a metal salt represented by the following formula (1) comprising an anionic and an alkali metal cation which is a base pair of a super acid and contains a perfluoroalkyl group; And

c) 0.01 to 10 parts by weight of a multifunctional crosslinking agent

It provides an acrylic pressure-sensitive adhesive composition comprising a.

[Formula 1]

In the formula of Formula 1,

M is an alkali metal,

R _f is a C 1-4 perfluoroalkyl group,

Y is carbon or sulfur, X is nitrogen or carbon, m is 1 or 2, n is 2 or 3,

M = 1 if Y is carbon, m = 2 if Y is sulfur,

N = 2 if X is nitrogen, n = 3 if X is carbon.

In another aspect, the present invention provides a polarizing plate comprising the acrylic pressure-sensitive adhesive composition as an adhesive layer on one side or both sides of the polarizing film.

In another aspect, the present invention provides a liquid crystal display device comprising a liquid crystal panel in which the polarizing plate is bonded to one side or both sides of the liquid crystal cell.

The acrylic pressure sensitive adhesive according to the present invention, the polarizing plate and the liquid crystal display device to which the pressure sensitive adhesive is applied, have no effect of whitening under moisture and heat resistance conditions without deterioration of the basic physical properties of the acrylic pressure sensitive adhesive such as antistatic, light transmittance, adhesiveness and durability.

Hereinafter, the present invention will be described in detail.

The acrylic pressure-sensitive adhesive composition of the present invention is 100 parts by weight of the acrylic copolymer, 0.001 to 25 parts by weight of the metal salt represented by the formula (1) consisting of an anionic and an alkali metal cation which is a base of a super acid and contains a perfluoroalkyl group, and a multifunctional crosslinking agent. It comprises 0.01 to 10 parts by weight.

The acrylic copolymer of a) used in the present invention is a copolymer of i) a (meth) acrylic acid ester monomer having an alkyl group having 1 to 12 carbon atoms and ii) a vinyl monomer having a crosslinkable functional group and / or an acrylic monomer. Can be used.

As the (meth) acrylic acid ester monomer having an alkyl group having 1 to 12 carbon atoms of (i), an alkyl ester having 1 to 12 carbon atoms of acrylic acid (or methacrylic acid) may be used. Particularly, when the alkyl group has a long chain form, the cohesive force of the adhesive Since this becomes low, in order to maintain cohesion force at high temperature, it is preferable to use the alkyl ester of C2-C8 of acrylic acid (or methacrylic acid).

Specifically, the (meth) acrylic acid ester monomer having an alkyl group having 1 to 12 carbon atoms may include butyl (meth) acrylate, 2-ethylbutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and ethyl (meth). Acrylate, methyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, n-octyl (meth) acrylic Elate, isooctyl (meth) acrylate, isononyl (meth) acrylate, etc. can be used individually or in mixture of 2 or more types.

The (meth) acrylic acid ester monomer having an alkyl group having 1 to 12 carbon atoms may further use a copolymerization monomer to control the glass transition temperature of the adhesive or to impart other functionalities, and examples thereof include acrylonitrile and (meth) acryl. Amide, N-methylacrylamide, styrene, methylstyrene, vinyltoluene, glycidyl (meth) acrylate, or vinyl acetate.

The (meth) acrylic acid ester monomer having an alkyl group having 1 to 12 carbon atoms as described above is preferably contained in an acrylic copolymer at 90 to 99.9% by weight, and when the content is less than 90% by weight, the initial adhesive strength is lowered. There is a problem that, if it exceeds 99.9% by weight may cause problems in durability due to the decrease in cohesion.

The vinyl monomer and / or the acrylic monomer having the crosslinkable functional group of ii) reacts with the crosslinking agent to impart cohesive force or adhesive strength by chemical bonding so that cohesive breakage of the adhesive does not occur under high temperature or high humidity conditions.

The vinyl monomer and / or acrylic monomer having the crosslinkable functional group may be 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2- Monomers containing a hydroxyl group such as hydroxyethylene glycol (meth) acrylate or 2-hydroxypropylene glycol (meth) acrylate; Or monomers containing carboxylic acids such as acrylic acid, methacrylic acid, acrylic acid duplex, itaconic acid, maleic acid, or maleic anhydride may be used alone or in combination of two or more thereof.

The vinyl monomer having a crosslinkable functional group and / or the acrylic monomer is preferably included in an acrylic copolymer in an amount of 0.1 to 10% by weight, and when the content is less than 0.1% by weight, aggregation breakdown is likely to occur under high temperature or high humidity conditions. In addition, the adhesive strength improvement effect is reduced, and when it exceeds 10% by weight, the compatibility decreases, which causes the surface migration to occur severely, the flow characteristics are reduced, and the stress relaxation ability decreases due to the cohesion increase. have.

The acrylic copolymer composed of the above components can be prepared by conventional methods such as solution polymerization, photopolymerization, bulk polymerization, suspension polymerization, or emulsion polymerization, and particularly preferably by solution polymerization. . At this time, the polymerization temperature is 50 ~ 140 ℃, it is good to mix the initiator in a state where the monomers are uniformly mixed.

The acrylic copolymer prepared as described above has a weight average molecular weight of 400,000 to 2,000,000, which is better for improving the viscoelasticity of the pressure-sensitive adhesive.

The metal salt consisting of an anion and an alkali metal cation which is a base group of the super acid of b) used in the present invention and contains a perfluoroalkyl group is low on metal cations due to the resonance structure of the anion and the high electronegativity of fluorine atoms. Coordination bondability and high hydrogenity make it excellent in compatibility with pressure-sensitive adhesives, have no surface migration, optically transparent, and prevent the whitening phenomenon of acrylic pressure-sensitive adhesive under moisture and heat conditions. It gives the property of. In addition, the metal salt imparts ionic conductivity to the pressure-sensitive adhesive.

Bistrifluoromethanesulfonimide (N (SO ₂ CF ₃ ) ₂ ⁻ ) as an anion among the metal salts represented by the general formula (1) including an anion and an alkali metal cation containing a counterbase of the super acid and containing a perfluoroalkyl group bis trifluoromethane carbonyl imide ^{_{(N (COCF 3) 2 -}} ), bis ethane sulfonimide _{(N (SO 2 C 2 F} 5) 2 -) pentafluoroethyl, bis pentafluoroethane carbonyl this imide _{(N (COC 2 F 5)} 2 -), bis perfluoro butane sulfonimide _{(N (SO 2 C 4 F} 9) 2 -), bis perfluorobutane carbonyl imide (N (COC ₄ F _{9) ^2-),} tris trifluoromethane sulfonyl nilme lactide _{(C (SO 2 CF 3)} 3 -) , or tris trifluoromethane carbonyl nilme lactide _{(C (SO 2 CF 3)} 3 -) , etc. may be used As the alkali metal cation, lithium (Li ⁺ ), sodium (Na ⁺ ), or potassium (K ⁺ ) may be used.

The metal salt consisting of an anion and an alkali metal cation which is a counterbase of the super acid and contains a perfluoroalkyl group is preferably contained in an amount of 0.001 to 25 parts by weight, and more preferably 0.01 to 10 parts by weight based on 100 parts by weight of the acrylic copolymer. It is included, and most preferably it is included in 0.1 to 5 parts by weight. If the content is less than 0.001 parts by weight, there is a problem that the antistatic ability is lowered, if it exceeds 25 parts by weight, there is a problem that the adhesion durability is weak due to the decrease in cohesive force. In addition, when the metal salt is used in an amount of 0.01 to 10 parts by weight and 0.1 to 5 parts by weight, the base material of the acrylic adhesive such as light transmittance and durability is excellent while there is no whitening phenomenon under moisture and heat resistance conditions. Excellent effect.

The multifunctional crosslinking agent of c) used in the present invention reacts with a carboxyl group, a hydroxyl group, and the like to increase the cohesive force of the adhesive.

The polyfunctional crosslinking agent may be an isocyanate compound, an epoxy compound, an aziridine compound, a metal chelate compound, or the like, and particularly preferably an isocyanate crosslinking agent.

The isocyanate compound is a polyol such as toluene diisocyanate, xylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isoform diisocyanate, tetramethyl xylene diisocyanate, naphthalene diisocyanate, or trimethylolpropane thereof. Reactants and the like can be used.

The said epoxy compound is ethylene glycol diglycidyl ether, triglycidyl ether, trimethylol propane triglycidyl ether, N, N, N ', N'- tetraglycidyl ethylenediamine, or glycerin diglycidyl ether, etc. Can be used.

The aziridine-based compound is N, N'-toluene-2,4-bis (1-aziridinecarboxide), N, N'-diphenylmethane-4,4'-bis (1-aziridinecarboxide) ), Triethylene melamine, bisisoprotaloyl-1- (2-methylaziridine), tri-1-aziridinylphosphine oxide, or the like can be used.

The metal chelate compound may be a compound in which polyvalent metals such as aluminum, iron, zinc, tin, titanium, antimony, magnesium, vanadium and the like are assigned to acetylacetone or ethyl acetoacetate.

It is preferable that the multifunctional crosslinking agent is contained in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the acrylic copolymer, and when the content is less than 0.01 parts by weight, cohesive failure is likely to occur under high temperature or high humidity conditions, and the effect of improving adhesion is improved. When the amount exceeds 10 parts by weight, there is a problem that the compatibility is reduced, causing surface migration to occur severely, flow characteristics are reduced, and stress relaxation is lowered due to cohesion.

The acrylic pressure-sensitive adhesive composition of the present invention comprising the above components may further use d) a silane coupling agent or e) a pressure-sensitive adhesive resin as necessary.

The silane coupling agent of d) serves to improve the heat resistance and moisture resistance by improving the adhesive stability when the acrylic pressure-sensitive adhesive is bonded to the glass plate. In particular, the silane coupling agent serves to help improve adhesion reliability when left for a long time under high temperature and high humidity.

The silane coupling agent is γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, vinyl Trimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-aminopropyltriethoxysilane, 3-isocyanatepropyltriethoxysilane Or gamma -acetoacetatepropyltrimethoxysilane, etc. can be used individually or in mixture of 2 or more types.

The silane coupling agent is preferably included in an amount of 0.005 to 5 parts by weight with respect to 100 parts by weight of the acrylic copolymer, and when the content is within the above range, when it is left for a long time under high temperature and high humidity to improve adhesion stability or adhesion reliability with the glass plate. It is possible to further improve the heat and moisture resistance characteristics.

The adhesive imparting resin of e) serves to adjust the adhesive performance of the acrylic adhesive.

The tackifying resin is (hydrogenated) hydrocarbon resin, (hydrogenated) rosin resin, (hydrogenated) rosin ester resin, (hydrogenated) tepene resin, (hydrogenated) terpene phenol resin, polymerized rosin resin, or polymerized rosin ester resin Etc. can be used individually or in mixture of 2 or more types.

The tackifier resin is preferably contained in 1 to 100 parts by weight with respect to 100 parts by weight of the acrylic copolymer, there is a problem that can reduce the compatibility or cohesion of the adhesive when the content exceeds 100 parts by weight.

In addition, the acrylic pressure-sensitive adhesive composition of the present invention may further use additives such as acrylic low molecular weight, epoxy resin, curing agent, UV stabilizer, antioxidant, colorant, reinforcing agent, filler, antifoaming agent, surfactant, or plasticizer.

The acrylic pressure-sensitive adhesive composition of the present invention composed of the above components can be prepared according to a conventional method, and of course, can be produced by methods such as thermosetting or photocuring.

As described above, the acrylic pressure-sensitive adhesive composition of the present invention preferably has a crosslinking density of 5 to 95%, and when the crosslinking density is less than 5%, the cohesive force of the adhesive is lowered and problems with adhesive durability such as bubbles or peeling may occur. If it exceeds%, there is a problem in that durability reliability such as lifting is weak.

In another aspect, the present invention provides a polarizing plate comprising the acrylic pressure-sensitive adhesive composition as the pressure-sensitive adhesive layer of the polarizing film, the polarizing plate comprises a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition on one side or both sides of the polarizing film.

The polarizing film or the polarizing element constituting the polarizing plate is not particularly limited, but, for example, the polarizing film is a film made by containing a polarizing component such as iodine or a dichroic dye in a film made of polyvinyl alcohol resin. Etc. can be used, and the thickness of these polarizing films is also not particularly limited, and can form a conventional thickness. In this case, the polyvinyl alcohol-based resin may be polyvinyl alcohol, polyvinyl formal, polyvinyl acetal and ethylene, saponified product of vinyl acetate copolymer.

On both sides of the polarizing film, a cellulose-based film such as triacetal cellulose, a polycarbonate film, a polyester-based film such as polyethylene terephthalate, a polyether sulfone-based film, polyethylene, polypropylene, cyclo-based or 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.

The method of forming the pressure-sensitive adhesive layer on the polarizing film as described above is not particularly limited, and for example, a method of applying and drying the pressure-sensitive adhesive using a bar coater or the like directly on the surface of the polarizing film, applying the pressure-sensitive adhesive to the surface of the peelable substrate and drying After this, a method of transferring and aging the pressure-sensitive adhesive layer formed on the surface of the peelable substrate to the polarizing film may be applied.

In addition, the polarizing plate of the present invention as described above 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, or 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 liquid crystal display device may include a liquid crystal panel obtained by bonding the pressure-sensitive adhesive applied polarizer to one side or both sides of the liquid crystal cell.

The acrylic pressure-sensitive adhesive composition of the present invention as described above may be used for industrial sheets, in particular, protective films, reflective sheets, structural adhesive sheets, photographic adhesive sheets, lane marking adhesive sheets, optical adhesive products, adhesives for electronic parts, and the like. In addition, a multi-layer laminate product, that is, a general commercial adhesive sheet products, medical patches, heat activated pressure sensitive adhesives (heat activated pressure sensitive adhesives), such as the concept of operation can be applied in the same application of course.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the scope of the present invention is not limited to the following examples.

EXAMPLE

Example 1

(Acrylic copolymer production)

98.3 parts by weight of n-butyl acrylate (BA), 0.5 part by weight of acrylic acid (AA), and hydroxyethyl methacrylate (2-HEMA) in a 1 L reactor equipped with a refrigeration system to allow nitrogen gas to be refluxed and for easy temperature control. 1.2 parts by weight of a monomer mixture was added, and then 100 parts by weight of ethyl acetate (EAc) was added as a solvent. Then, after purging nitrogen gas for 1 hour to remove oxygen, it was maintained at 62 ℃. After the mixture was uniform, 0.03 parts by weight of azobisisobutyronitrile (AIBN) diluted to 50% concentration in ethyl acetate was added as a reaction initiator, and reacted for 8 hours to prepare an acrylic copolymer.

(Mixing process)

100 parts by weight of the acrylic copolymer prepared above, 0.5 parts by weight of tolylene diisocyanate adduct (TDI-1) of isocyanate-based trimethylolpropane as a crosslinking agent, and 0.1 parts by weight of lithium bistrifluorosulfonimide were added at an appropriate concentration. After diluting and uniformly mixing, after coating and drying on a release paper to prepare a uniform adhesive layer of 25 ㎛.

(Plywood process)

The pressure-sensitive adhesive layer prepared above was tacked on an 185 μm thick iodine polarizing plate.

Examples 2-15 and Comparative Examples 1-8

Example 1 was carried out in the same manner as in Example 1, except that the composition and the composition ratio as shown in Table 1 below. At this time, the unit of Table 1 is a weight part.

division Acrylic Copolymer Crosslinking agent Metal salt n-BA AA EA 2-HEMA 2-HEA A B C D E F Example One 98.3 0.5 - 1.2 - 0.5 0.1 - - - - - 2 98.3 0.5 - 1.2 - 0.5 4 - - - - - 3 98.3 0.5 - 1.2 - 0.5 20 - - - - - 4 88.0 - 9.5 - 2.5 0.5 4 - - - - - 5 98.3 0.5 - 1.2 - 0.5 - 0.1 - - - - 6 98.3 0.5 - 1.2 - 0.5 - 4 - - - - 7 98.3 0.5 - 1.2 - 0.5 - 20 - - - - 8 88.0 - 9.5 - 2.5 0.5 - 4 - - - - 9 98.3 0.5 - 1.2 - 0.5 - - 0.1 - - - 10 98.3 0.5 - 1.2 - 0.5 - - 4 - - - 11 98.3 0.5 - 1.2 - 0.5 - - 20 - - - 12 88.0 - 9.5 - 2.5 0.5 - - 4 - - - 13 98.3 0.5 - 1.2 - 0.5 4 4 - - - - 14 98.3 0.5 - 1.2 - 0.5 - 4 4 - - - 15 98.3 0.5 - 1.2 - 0.5 4 - 4 - - - Comparative example One 98.3 0.5 - 1.2 - 0.5 - - - 0.1 - - 2 98.3 0.5 - 1.2 - 0.5 - - - 4 - - 3 98.3 0.5 - 1.2 - 0.5 - - - - 0.1 - 4 98.3 0.5 - 1.2 - 0.5 - - - - 4 - 5 98.3 0.5 - 1.2 - 0.5 - - - - - 0.1 6 98.3 0.5 - 1.2 - 0.5 - - - - - 4 7 98.3 0.5 - 1.2 - 0.5 - - - - - - 8 98.3 0.5 - 1.2 - 0.5 30 - - - - - N-BA: n-butyl acrylate
AA: acrylic acid
EA: ethyl acrylate
2-HEMA: 2-hydroxyethyl methacrylate
2-HEA: 2-hydroxyethyl acrylate
Crosslinking agent: Tolylene diisocyanate adduct of isocyanate trimethylolpropane
A: lithium bistrifluoromethanesulfonimide (LiN (SO ₂ CF ₃ ) ₂ )
B: lithium bispentafluoroethanesulfonimide (LiN (SO ₂ C ₂ F ₅ ) ₂ )
C: potassium bistrifluoromethanesulfonimide (KN (SO ₂ CF ₃ ) ₂ )
D: lithium perchlorate (LiClO ₄ )
E: lithium trifluoromethanesulfonate (LiSO ₃ CF ₃ )
F: sodium perchlorate (NaClO ₄ )

Haze, durability, and surface resistance were measured by the following method using the polarizing plates prepared in Examples 1 to 15 and Comparative Examples 1 to 8, and the results are shown in Table 2 below.

A) Haze-The whitening phenomenon was evaluated by measuring the haze of the adhesive in which PET films were laminated on both sides. Using the measurement sample, the polarizing plates prepared in Examples 1 to 15 and Comparative Examples 1 to 8 were cut out to 40 × 70 mm 2, and diffused transmittance was obtained by using an integrated formula light transmittance measuring device according to JIS K7150 and ASTM D 1003-95. Td and total light transmittance Ti were measured. At this time, haze defines the percentage of Td to Ti. Then, the sample was left for 1000 hours at a temperature of 60 ° C. and a relative humidity of 90%, and then the haze was measured in the same order, and the whitening phenomenon was evaluated by comparing and evaluating the haze before and after standing.

B) Durability-The polarizing plates (90 mm × 170 mm) prepared in Examples 1 to 15 and Comparative Examples 1 to 8 were cross-linked on both sides of glass polarizers (110 mm × 190 mm × 0.7 mm). It was attached in a state. At this time, the clean product operation was performed so that a bubble or a foreign substance might not generate | occur | produce at 5 kg / cm <2> by the applied pressure. In order to understand the heat and moisture resistance of these specimens, it was observed for 1000 hours at 60 ℃ and 90% relative humidity, and then bubbles or peeling occurred. Immediately before evaluating the state of the specimen, it was carried out for 24 hours at room temperature (evaluation criteria ○: no bubbles or peeling phenomenon / ×: bubbles or peeling phenomenon).

C) Surface Resistance-After removing the release film from the polarizing plates prepared in Examples 1 to 15 and Comparative Examples 1 to 8, the surface resistance of the adhesive surface was measured. At this time, the surface resistance was measured after applying a voltage of 500 V for 1 minute at a temperature of 23 ℃ and 50% relative humidity.

division Durability Reliability Surface Resistance (Ω / □) Haze 80 ℃, 1000 hr 60 ° C, 90% RH, 1000 hr Example One ○ ○ 7 × 10 ¹¹ 0.2 2 ○ ○ 4 × 10 ⁹ 0.2 3 ○ ○ 1 × 10 ⁸ 0.3 4 ○ ○ 6 × 10 ⁹ 0.2 5 ○ ○ 1 × 10 ¹² 0.2 6 ○ ○ 8 × 10 ⁹ 0.2 7 ○ ○ 2 × 10 ⁸ 0.3 8 ○ ○ 1 × 10 ¹⁰ 0.2 9 ○ ○ 3 × 10 ¹³ 0.2 10 ○ ○ 2 × 10 ¹¹ 0.2 11 ○ ○ 5 × 10 ⁹ 0.3 12 ○ ○ 3 × 10 ¹¹ 0.2 13 ○ ○ 2 × 10 ⁹ 0.2 14 ○ ○ 7 × 10 ⁹ 0.2 15 ○ ○ 4 × 10 ⁹ 0.2 Comparative example One ○ × 8 × 10 ¹² 1.2 2 × × 9 × 10 ¹¹ 29.3 3 ○ × 4 × 10 ¹² 0.9 4 ○ × 3 × 10 ¹¹ 25.6 5 ○ × 2 × 10 ¹³ 2.0 6 × × 3 × 10 ¹² 38.1 7 ○ ○ 1 × 10 ¹⁴ 0.2 8 × × 7 × 10 ⁷ 0.8

Through the above Table 2, the flat plate of Examples 1 to 15 to which the acrylic adhesive composition containing the metal salt represented by the formula (1) according to the present invention is applied is a comparative example without using the metal salt represented by the formula (1) as in the present invention Even when using the metal salt represented by 1 to 8 and the general formula (1) of the present invention, the durability and antistatic performance was excellent compared to Comparative Example 8, the content of which exceeds 25 parts by weight, in particular, no whitening phenomenon even under moisture and heat conditions Could confirm.

In addition, using the Examples 1 to 3 and Comparative Examples 7 or 8, the glass adhesion and durability dependence according to the weight of lithium bistrifluoromethanesulfonimide, which is a kind of the metal salt represented by Formula 1 used in the present invention It measured and the result is shown in following Table 3.

The glass adhesive force was aged for 7 days at room temperature (23 ° C., 60% RH) of the pressure-sensitive adhesive coated polarizing plate prepared in Examples 1 to 3 and Comparative Examples 7 or 8, each polarizing plate 1 inch × 6 inches After cutting by using a 2 kg rubber roller attached to 0.7 mm thick alkali-free glass, stored at room temperature and measured after 1 hour, after aging at 50 ℃ for 4 hours and then stored at room temperature for 1 hour Measured. At this time, the peel strength was measured at a rate of 30 mm / min and an angle of 180 ° using a tensile tester.

division Glass adhesive force (g / 25 mm) Durability Reliability Early ferment Example 1 440 575 ○ Example 2 500 650 ○ Example 3 700 800 ○ Comparative Example 7 440 570 ○ Comparative Example 8 250 300 ×

As shown in Table 3, in Examples 1 to 3 according to the present invention, it was confirmed that the glass adhesion increased as the content of lithium bistrifluoromethanesulfonimide, which is a metal salt of Formula 1, increased. On the other hand, even in the case of using lithium bistrifluoromethanesulfonimide, in Comparative Example 8 used at 25 parts by weight or more, it was confirmed that not only the glass adhesion was lowered, but also the durability was also lowered. In addition, in Comparative Example 7 in which the metal salt was not used, the glass adhesive force showed a certain degree of performance, but it was found that the surface resistance value was too high and did not have an antistatic ability (see Table 2).

Although only described in detail with respect to the described embodiments of the present invention, it will be apparent to those skilled in the art that various modifications and variations are possible within the technical spirit of the present invention, it is natural that such variations and modifications belong to the appended claims. .

Claims (11)

In the acrylic pressure-sensitive adhesive composition,
a) 100 parts by weight of the acrylic copolymer;
b) 0.001 to 25 parts by weight of a metal salt represented by the following formula (1) comprising an anionic and an alkali metal cation which is a base pair of a super acid and contains a perfluoroalkyl group; And
c) 0.01 to 10 parts by weight of a multifunctional crosslinking agent
Including,
The acrylic copolymer of the above a) iii) butyl (meth) acrylate, 2-ethylbutyl (meth) acrylate, ethyl (meth) acrylate, methyl (meth) acrylate, n-propyl (meth) acrylate, 90 to 99.9 wt% of at least one monomer selected from the group consisting of isopropyl (meth) acrylate, t-butyl (meth) acrylate and pentyl (meth) acrylate, and ii) vinyl monomers having crosslinkable functional groups and acrylics Prepared by copolymerizing 0.1 to 10% by weight of at least one monomer selected from the group consisting of monomers,
The polyfunctional crosslinking agent is an acrylic pressure-sensitive adhesive composition for a polarizing plate, characterized in that at least one polyfunctional crosslinking agent selected from the group consisting of an isocyanate compound, an epoxy compound and a metal chelate compound.
[Formula 1]

In the formula of Formula 1,
M is an alkali metal,
R _f is a C 1-4 perfluoroalkyl group,
Y is carbon or sulfur, X is nitrogen or carbon, m is 1 or 2, n is 2 or 3,
M = 1 if Y is carbon, m = 2 if Y is sulfur,
N = 2 if X is nitrogen, n = 3 if X is carbon. The method of claim 1,
The monomer of i) is selected from the group consisting of acrylonitrile, (meth) acrylamide, N-methylacrylamide, styrene, methylstyrene, vinyltoluene, glycidyl (meth) acrylate, and vinyl acetate. It is used in mixture with the monomer used, The acrylic adhesive composition for polarizing plates characterized by the above-mentioned. The method of claim 1,
The monomer selected from the group consisting of a vinyl monomer having a crosslinkable functional group of ii) and an acrylic monomer is 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxy With butyl (meth) acrylate, 2-hydroxyethylene glycol (meth) acrylate, 2-hydroxypropylene glycol (meth) acrylate, acrylic acid, methacrylic acid, acrylic acid duplex, itaconic acid, maleic acid, and maleic anhydride 1 type or more is chosen from the group which consists of acrylic adhesive compositions for polarizing plates. The method of claim 1,
The acrylic pressure-sensitive adhesive composition for polarizing plates, characterized in that the weight average molecular weight of the acrylic copolymer of a) is 400,000 to 2,000,000. The method of claim 1,
Wherein b) second conjugate base of a strong acid and perfluoro methane sulfonic imide anion and the alkali metal cation salts are bis-trifluoromethyl made of containing alkyl (N (SO ₂ CF _{3) 2} ^-), methane-bis-trifluoromethyl carbonyl sulfonimide ^{_{(N (COCF 3) 2 -}} ), ethane sulfonimide as bis-pentafluoropropane _{(N (SOC 2 F 5)} 2 -), bis pentafluoroethane carbonyl imide (N (COC ₂ F _{5) 2} ^-), bis perfluoro butane sulfonimide _{(N (SO 2 C 4 F} 9) 2 -), bis perfluoro butane carbonyl imide _{(N (COC 4 F 9)} 2 -), tris Anion selected from trifluoromethanesulfonylmethide (C (SO ₂ CF ₃ ) ₃ ⁻ ), and tristrifluoromethanecarbonylmethide (C (SO ₂ CF ₃ ) ₃ ⁻ ), and lithium (Li ⁺ ) , Sodium (Na ⁺ ), and potassium (K ⁺ ), the acrylic pressure-sensitive adhesive composition for a polarizing plate, characterized by consisting of. The method of claim 1,
The acrylic pressure-sensitive adhesive composition for polarizing plates, wherein a metal salt composed of an anion and an alkali metal cation, which is a base of the super acid of b) and contains a perfluoroalkyl group, is contained in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the acrylic copolymer. The method of claim 1,
The acrylic pressure-sensitive adhesive composition for polarizing plates, characterized in that the metal salt consisting of an anion and an alkali metal cation which is a base of the super acid of b) and contains a perfluoroalkyl group is contained in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the acrylic copolymer. The method of claim 1,
The acrylic pressure sensitive adhesive composition further comprises d) a silane coupling agent or e) an adhesive imparting resin. The method of claim 8,
The silane coupling agent of d) is γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane, 3-mercaptopropyltrimethoxy Silane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-aminopropyltriethoxysilane, 3-isocyanatepropyltri At least 1 type is chosen from the group which consists of an ethoxysilane and (gamma)-aceto acetate propyl trimethoxysilane, and it contains 0.005-5 weight part with respect to 100 weight part of acrylic copolymers, The acrylic adhesive composition for polarizing plates. The method of claim 8,
The tackifying resin of e) is (hydrogenated) hydrocarbon resin, (hydrogenated) rosin resin, (hydrogenated) rosin ester resin, (hydrogenated) tepene resin, (hydrogenated) terpene phenol resin, polymerization rosin resin, and polymerization furnace At least one selected from the group consisting of gin ester resins, the acrylic pressure-sensitive adhesive composition for a polarizing plate, characterized in that contained in 1 to 100 parts by weight with respect to 100 parts by weight of the acrylic copolymer. The method of claim 1,
The acrylic pressure-sensitive adhesive composition further comprises an additive selected from the group consisting of acrylic low molecular weight, epoxy resin, curing agent, ultraviolet stabilizer, antioxidant, colorant, reinforcing agent, filler, antifoaming agent, surfactant, and plasticizer. Acrylic adhesive composition for polarizing plates to be.