KR101938897B1 - Acrylic copolmer, adhesive composition containing threrof and polarizing plate - Google Patents

Abstract

The present invention relates to an acrylic copolymer, a pressure-sensitive adhesive composition containing the same, and a polarizing plate. More particularly, the present invention relates to a pressure-sensitive adhesive composition comprising 35 to 84.9 parts by weight of a (meth) acrylate monomer having an alkyl group having 4-12 carbon atoms, 0.1 to 5 parts by weight of 4-hydroxybutyl acrylate, 5 to 10 parts by weight of acrylic acid, and 5 to 30 parts by weight of methacrylate, and having an average molecular weight (Mw in terms of polystyrene) of 1,000,000 or more Is used to increase the crosslinking density to improve the cohesive force of the composition, the adhesion durability in the severe condition (high temperature or high temperature and high humidity) is excellent, the curing period is shortened, and the light leakage prevention And a polarizing plate.

Description

TECHNICAL FIELD [0001] The present invention relates to an acrylic copolymer, a pressure-sensitive adhesive composition containing the same and a polarizer,

The present invention relates to a pressure-sensitive adhesive composition and a polarizer excellent in durability.

Adhesive is a material that adheres sufficiently to the adherend even under the application of pressure alone. It exhibits a viscoelastic behavior in which the cohesion is lower than that of the adhesive, the stress relaxation is faster, and the deformation easily occurs with respect to external force.

 The raw materials used in the pressure-sensitive adhesive are mostly elastic materials such as natural rubber, synthetic rubber, acrylic, and silicone, so they have viscoelastic properties by mixing low molecular weight materials to impart viscous properties.

 Recently, acrylic pressure-sensitive adhesives among the raw materials of pressure-sensitive adhesives have been rapidly used instead of rubber-based pressure-sensitive adhesives, and they can be used in a wide variety of forms such as solvent type, water-based emulsion type, hot melt type and 100% solid reaction type pressure-sensitive adhesive.

The acrylic pressure-sensitive adhesive is excellent in weather resistance, heat resistance, cold resistance and oil resistance as compared with the rubber-based pressure-sensitive adhesive, and can be made relatively easily for various purposes and applications. Therefore, it has been suggested that the adherence of acrylic adhesives has enabled the adhesive products to be used in a variety of different applications as at present.

Adhesive properties can be generally evaluated by initial tack, adhesion and shear strength.

The initial cohesion is related to the glass transition temperature (Tg) of the polymer forming the pressure-sensitive adhesive, and the cohesion is related to the glass transition temperature and cohesion of the polymer. When cohesive force is applied to the adherend, the cohesive force is a force between the molecules of the pressure sensitive adhesive. If the cohesive force between the molecules is high, the interfacial destruction of the pressure sensitive adhesive occurs. If the cohesive strength is low, the cohesive failure occurs and the remnant is left on the adherend. It is ideal to design the adhesive so that it occurs.

In recent years, the price of polarizer materials has been lowered in line with the trend toward lower cost of LCD materials. In particular, interest in reducing the price of polarizer protective film, which accounts for more than 50% of the cost of polarizer materials, is of interest. Accordingly, attempts have been made to use a polymethyl methacrylate resin having a high transmittance and low cost instead of conventional cellulose and cycloolefin polymer resins as a polarizer protective film.

However, the film containing the polymethylmethacrylate resin has a problem that the shrinkage ratio under the heat-resistant condition is large, and thus defects such as peeling due to shrinkage stress are liable to occur during the production of the polarizing plate.

In order to improve the adhesion durability of the high shrinkage polarizing plate, Korean Patent No. 930,808 discloses an epoxy acrylic adhesive which contains an ester-based tackifying resin and improves initial adhesion, adhesion and cohesion. However, the pressure-sensitive adhesive composition containing the tackifier resin has a disadvantage that it does not exhibit an effect of improving the cohesive force to such an extent as to overcome the shrinkage characteristics of the polymethyl methacrylate polarizer protective film. Further, since the tackifier resin is a low molecular weight oligomer, durability may be deteriorated by bleeding-out, and further technology for improving the tackifier resin needs to be added.

The present invention relates to a polarizing plate comprising a cellulose resin and a cycloolefin resin as well as a film using a polymethylmethacrylate resin. The polarizing plate can not withstand the shrinkage stress of the polarizer, Sensitive adhesive composition which can improve the sticking durability of a polarizing plate by solving the problem that peeling failure is caused in a high humidity environment (e.g., high humidity).

In order to attain the above object, the present invention relates to a curable composition comprising 35 to 84.9 parts by weight of a (meth) acrylate monomer having an alkyl group having 4 to 12 carbon atoms, 5 to 20 parts by weight of benzyl methacrylate, 0.1 to 5 parts by weight of 4-hydroxybutyl acrylate 5 to 30 parts by weight of acrylic acid, 5 to 10 parts by weight of acrylic acid, and 5 to 30 parts by weight of methyl acrylate, and having a weight average molecular weight (Mw in terms of polystyrene) of 1,000,000 or more.

Preferably, the weight average molecular weight may range from 1 million to 200.

Preferably, the acrylic copolymer includes 47 to 76.5 parts by weight of a (meth) acrylate monomer having an alkyl group of 4 to 12 carbon atoms, 8 to 12 parts by weight of benzyl methacrylate, 0.5 to 3 parts by weight of 4- 5 to 8 parts by weight of acrylic acid, and 10 to 30 parts by weight of methyl acrylate.

The present invention also provides a pressure-sensitive adhesive composition containing the acrylic copolymer.

The pressure-sensitive adhesive composition may further contain a crosslinking agent.

Further, the present invention provides a polarizer wherein a polarizer protective film is bonded to at least one surface of a polarizer, and a pressure-sensitive adhesive layer containing the pressure-sensitive adhesive composition is formed on the polarizer protective film.

The polarizer protective film may have a water contact angle of 30 to 80 °.

The polarizer protective film may be polymethyl methacrylate.

The polarizing plate was cut into a size of 90 mm × 170 mm, and the specimen attached to both sides of the glass substrate so that the optical absorption axes crossed each other was left at a temperature of 80 ° C. for 1000 hours, and the occurrence of bubbles or peeling could be less than 5 have.

The polarizing plate was cut into a size of 90 mm x 170 mm, and the specimen adhered to both sides of the glass substrate so that the optical absorption axes crossed each other was left for 1000 hours at a temperature of 60 DEG C and 90% RH. May be less than five.

The pressure-sensitive adhesive composition containing the acrylic copolymer of the present invention uses a monomer having a high glass transition temperature, increases the number of hydrogen bonds in the copolymer to improve the glass transition temperature, improves the crosslinking density by controlling the content of acrylic acid, The molecular weight is increased to increase the entanglement between the acrylic copolymers and improve the cohesive force of the composition, thereby making it possible to improve the adhesion durability under severe conditions (high temperature or high temperature and high humidity).

In particular, when applied to a polarizing plate produced from a film using a polymethyl methacrylate resin, it has an advantage of having excellent adhesion and adhesion durability.

In addition, the pressure-sensitive adhesive composition containing the acrylic copolymer of the present invention has an advantage that the curing period is shortened and the light-shielding property equivalent to that of the prior art can be maintained.

The present invention relates to a pressure-sensitive adhesive composition and a polarizer excellent in durability.

Hereinafter, the present invention will be described in detail.

35 to 84.9 parts by weight of a (meth) acrylate monomer having an alkyl group of 4 to 12 carbon atoms, 5 to 20 parts by weight of benzyl methacrylate, 0.1 to 5 parts by weight of 4-hydroxybutyl acrylate, 5 to 10 parts by weight of acrylic acid And 5 to 30 parts by weight of methyl acrylate. Here, (meth) acrylate means acrylate and methacrylate, and the content of each component is based on the solid content.

The acrylic copolymer has a weight average molecular weight (polystyrene conversion, Mw) of not less than 1,000,000 and not more than two hundred thousand, preferably 100 to 1,500,000 as measured by Gel Permeation Chromatography (GPC). If the weight average molecular weight is less than 1,000,000, the cohesive force is insufficient and peeling or bubble defects may occur under the heat-resistant condition. If the weight average molecular weight is more than 2,000,000, the acrylic copolymer may be excessively tangled, Defects such as edgewise may occur.

Each of the monomers contained in the acrylic copolymer is already known in the art, but the present invention is characterized in that these combinations are selectively used in order to increase the crosslinking density and improve the cohesive force, and the content ranges thereof are produced.

Examples of the (meth) acrylate monomer having an alkyl group having 4 to 12 carbon atoms include (meth) acrylates derived from an aliphatic alcohol having 4 to 12 carbon atoms such as n-butyl (meth) acrylate, (Meth) acrylate, octyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, octyl , And lauryl (meth) acrylate. These may be used alone or in combination of two or more. Of these, n-butyl acrylate, 2-ethylhexyl acrylate or a mixture thereof is preferable.

The (meth) acrylate monomer having an alkyl group having 4 to 12 carbon atoms contains 35 to 84.9 parts by weight, preferably 47 to 76.5 parts by weight. If the content is less than 35 parts by weight, bubbles may be mixed at the time of bonding due to insufficient tackiness. If the content exceeds 84.9 parts by weight, the cohesive force may be insufficient due to the lowering of the glass transition temperature and the lack of hydrogen bond formation, .

The benzylmethacrylate serves to control the birefringence to minimize light leakage and improve the glass transition temperature to improve the heat resistance.

Such benzyl methacrylate contains 5 to 20 parts by weight, preferably 8 to 12 parts by weight. If the content is less than 5 parts by weight or more than 20 parts by weight, the birefringence may deviate from a desired range and light leakage characteristics may be deteriorated.

The 4-hydroxybutylacrylate is a crosslinking monomer and reacts with the crosslinking agent to improve the cohesion of the acrylic copolymer.

Such 4-hydroxybutyl acrylate is contained in an amount of 0.1 to 5 parts by weight, preferably 0.5 to 3 parts by weight. If the content is less than 0.1 parts by weight, the effect of improving the cohesive strength may be insufficient. If the content is more than 5 parts by weight, crosslinking may be excessively formed, resulting in deteriorated adhesive strength and peeling failure in heat resistance.

The acrylic acid acts as an acid catalyst which forms a hydrogen bond in the copolymer or reacts with the crosslinking agent to form a crosslinking to improve the cohesion of the pressure-sensitive adhesive or improve the reaction rate of 4-hydroxybutyl acrylate with the crosslinking agent, It contributes to the shortening effect. In addition, it acts as a polar functional group to improve adhesive force by polar interaction between adhesive and glass.

Such acrylic acid contains 5 to 10 parts by weight, preferably 5 to 8 parts by weight. If the content is less than 5 parts by weight, the effect of improving the cohesion and adhesion may be insufficient and the curing shortening effect may be insufficient. If the content is more than 10 parts by weight, the cohesive force may be excessively lowered, And the stability of the crude liquid solution may deteriorate due to the excessive crosslinking catalyst effect.

The methyl acrylate has a high glass transition temperature to improve the cohesive force of the pressure-sensitive adhesive, and because it has a polarity relative to butyl acrylate, it plays a role of improving adhesion by polar interaction with the glass.

Such methyl acrylate is contained in an amount of 5 to 30 parts by weight, preferably 10 to 30 parts by weight. If the content is less than 5 parts by weight, the effect of improving the cohesive strength is insufficient. If the content is more than 30 parts by weight, the fluidity of the polymer itself may be decreased, which may cause problems such as generation of water-

In addition to the monomer, the acrylic copolymer of the present invention may further contain a crosslinkable monomer having a functional group of hydroxy or carboxyl group. At this time, the crosslinkable monomer serves to reinforce the cohesive strength or adhesive strength of the pressure-sensitive adhesive composition by chemical bonding, thereby imparting durability and cutability.

Examples of the monomer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl Hydroxypropyleneglycol (meth) acrylate, 2-hydroxyethyleneglycol (meth) acrylate, 2-hydroxypropyleneglycol (meth) acrylate, hydroxyalkylene glycol Hydroxyhexyl vinyl ether, 8-hydroxyoctyl vinyl ether, 9-hydroxynonyl vinyl ether, and 10-hydroxydecyl vinyl ether, etc. .

Examples of the monomer having a carboxyl group include monovalent acids such as (meth) acrylic acid and crotonic acid; Dicarboxylic acids such as maleic acid, itaconic acid, and fumaric acid, and monoalkyl esters thereof; 3- (meth) acryloylpropionic acid; A succinic anhydride ring-opening addition adduct of 2-hydroxyalkyl (meth) acrylate in which the alkyl group has 2 to 4 carbon atoms, anhydrous succinic ring opening adduct of a hydroxyalkylene glycol (meth) acrylate having 2 to 4 carbon atoms in the alkylene group , Compounds obtained by ring-opening addition of succinic anhydride to caprolactone adducts of 2-hydroxyalkyl (meth) acrylates whose alkyl groups have 2-3 carbon atoms, and among these, (meth) acrylic acid is preferable.

The crosslinkable monomer is preferably contained in an amount of 0.05 to 10 parts by weight, more preferably 0.1 to 8 parts by weight, based on 100 parts by weight of the alkyl (meth) acrylate monomer having 4 to 12 carbon atoms. When the content is less than 0.05 part by weight, the cohesive force of the pressure-sensitive adhesive becomes small and durability may be deteriorated. When the content is more than 10 parts by weight, a high gel fraction may lower the adhesive strength and cause durability problems.

In addition, other polymerizable monomers other than the above-mentioned monomers may be further added in an amount not lowering the adhesive force, for example, 10 parts by weight or less based on 100 parts by weight of the total monomers used in the production of the acrylic copolymer.

The method for producing the copolymer is not particularly limited and can be produced by methods such as bulk polymerization, solution polymerization, emulsion polymerization or suspension polymerization, which are commonly used in the art, and solution polymerization is preferable. In addition, a solvent, a polymerization initiator, a chain transfer agent for molecular weight control and the like which are usually used in polymerization can be used.

Further, the present invention is characterized by a pressure-sensitive adhesive composition containing the acrylic copolymer. The pressure-sensitive adhesive composition may further contain a crosslinking agent.

The crosslinking agent is a component for reinforcing the cohesive force of the pressure-sensitive adhesive by properly crosslinking the copolymer, and the kind thereof is not particularly limited. Examples thereof include isocyanate compounds and epoxy compounds, which may be used alone or in combination of two or more.

Examples of the isocyanate compound include tolylene diisocyanate, xylene diisocyanate, 2,4-diphenylmethane diisocyanate, 4,4-diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, tetramethyl xylene diisocyanate , Diisocyanate compounds such as naphthalene diisocyanate; An adduct obtained by reacting 3 moles of a diisocyanate compound with 1 mole of a polyhydric alcohol compound such as trimethylolpropane, an isocyanurate compound in which 3 moles of a diisocyanate compound is self-condensed, a diisocyanate obtained from 2 moles of 3 moles of a diisocyanate compound And multifunctional isocyanate compounds containing three functional groups such as burette, triphenylmethane triisocyanate and methylene bistriisocyanate in which the remaining one mole of diisocyanate is condensed in urea.

Examples of the epoxy compound include ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol Hexanediol diglycidyl ether, polytetramethylene glycol diglycidyl ether, glycerol diglycidyl ether, glycerol triglycidyl ether, glycerol diglycidyl ether, glycerol diglycidyl ether, Diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, resorcinol diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, trimethylol propane triglycidyl ether, pentaerythritol Polyglycidyl ether, sorbitol polyglycidyl ether, adipic acid diglycidyl ester, phthalic acid diglycidyl ester, tris (glycidyl) isocyanurate N, N ', N'-tetraglycidyl-m-glycidoxyethyl isocyanurate, 1,3-bis (N, N-glycidylaminomethyl) cyclohexane, Xylylenediamine, and the like.

In addition, an isocyanate compound, an epoxy compound, and a melamine compound may be used alone or in admixture of two or more.

Examples of the melamine-based compound include hexamethylol melamine, hexamethoxymethyl melamine, and hexabutoxymethyl melamine.

The crosslinking agent is preferably contained in an amount of 0.1 to 15 parts by weight, more preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the copolymer based on the solid content. When the content is less than 0.1 parts by weight, the cohesive force becomes small due to insufficient crosslinking, resulting in deterioration of durability such as peeling and deterioration of cutability. If the content is more than 15 parts by weight, excessive crosslinking reaction may cause a problem of relaxation of residual stress have.

In addition, the pressure-sensitive adhesive composition of the present invention may further comprise a silane coupling agent.

The kind of the silane coupling agent is not particularly limited, and examples thereof include vinylchlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3- 3-glycidoxypropyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, Acryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-acryloxypropyltrimethoxysilane , N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (aminoethyl) Methyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1,3-dimethylbutylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, 3-chloropropyltrimethoxysilane, 3- Dimethoxysilane, 3-mercaptopropyltrimethoxysilane, bis (triethoxysilylpropyl) tetrasulfide, 3-isocyanatepropyltriethoxysilane, and the like. These may be used alone or in combination of two or more.

The silane coupling agent may be contained in an amount of 0 to 10 parts by weight, preferably 0.005 to 5 parts by weight, based on 100 parts by weight of the copolymer based on the solid content. If the content exceeds 10 parts by weight, the durability may be lowered.

Further, the pressure-sensitive adhesive composition may further contain an antistatic agent, and an ionic antistatic agent is preferable. The ionic antistatic agent is an ionic salt composed of an anion and a cation, and is not particularly limited as long as it can impart ionic conductivity to the adhesive.

A cation selected from the group consisting of an alkali metal salt, an ammonium salt, a sulfonium salt and a phosphonium salt; An ionic salt consisting of an anion selected from the group consisting of a fluorine-containing inorganic salt, a fluorine-containing organic salt and an iodide ion.

Such an ionic antistatic agent may be contained in an amount of 0.1 to 5 parts by weight, preferably 0.5 to 3 parts by weight, based on 100 parts by weight of the acrylic copolymer. When the content is less than 0.1 part by weight, the antistatic property may be insufficient. When the content is more than 5 parts by weight, it may be difficult to secure durability.

In addition to the above components, the pressure-sensitive adhesive composition may further contain additives such as a tackifier resin, an antioxidant, a corrosion inhibitor, a leveling agent, a surface lubricant, a dye, a pigment, and the like in order to control adhesion, cohesion, viscosity, , Defoaming agents, fillers, light stabilizers, and the like.

Further, the present invention is characterized in that a polarizer protective film is bonded to at least one surface of a polarizer, and a pressure-sensitive adhesive layer containing the pressure-sensitive adhesive composition is formed on the polarizer protective film.

The polarizer protective film may be a film of a cellulose-based, polyester-based, polycarbonate-based, acrylic-based, water-based, polyolefin-based, polyvinyl chloride-based, amide-based, imide-based or polyether sulfone-based resin; Sulfone based resin; Polyether sulfone type resin; Polyether ether ketone resin; A sulfided polyphenylene resin; Vinyl alcohol-based resin; Vinylidene chloride resins; Vinyl butyral resin; Allylate series resin; Polyoxymethylene type resin; A thermoplastic resin such as epoxy resin, a thermosetting resin such as (meth) acrylic, urethane, acrylic urethane, epoxy, or silicone, or a film made of an ultraviolet curable resin can be used.

In particular, the pressure-sensitive adhesive layer of the present invention is not only easy to adhere to a non-polar film which is not easily adhered by an acrylic pressure-sensitive adhesive, but also has excellent adhesive durability.

The non-polar film may have a water contact angle of 30 to 50 DEG, preferably, polymethyl methacrylate.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention. Such variations and modifications are intended to be within the scope of the appended claims.

Manufacturing example  : Acrylic copolymer preparation

Manufacturing example  One

56 parts by weight of n-butyl acrylate (BA), 30 parts by weight of methyl acrylate (MA), and 8 parts by weight of benzyl methacrylate (BzMA) were added to a 1 L reactor equipped with a cooling device for regulating the temperature of the nitrogen gas, , 5 parts by weight of acrylic acid (AA), and 1 part by weight of 4-hydroxybutyl acrylate (4-HBA) were put in a flask, and 80 parts by weight of ethyl acetate (EAc) was added as a solvent. Nitrogen gas was then purged for 1 hour to remove oxygen and then maintained at 70 ° C. After the mixture was homogeneously mixed, 0.07 part by weight of azobisisobutyronitrile (AIBN) was added as a reaction initiator and reacted for 8 hours to prepare an acrylic copolymer (weight average molecular weight: about 1.4 million).

Manufacturing example  2

The acrylic copolymer was prepared in the same manner as in Preparation Example 1 except that the components were mixed and reacted as shown in Table 1 below.

division
(Parts by weight) Monomer menstruum Reaction temperature
(° C) Weight average molecular weight
(just) BA MA BzMA AA 4-HBA EAc Production Example 1 56 30 8 5 One 80 70 138 Production Example 2 66 20 8 5 One 80 70 142 Production Example 3 76 10 8 5 One 80 70 135 Production Example 4 54 30 8 7 One 80 70 132 Production Example 5 51 30 8 10 One 80 70 145 Production Example 6 49 30 15 5 One 80 70 132 Production Example 7 54 30 8 5 3 80 70 135 Comparative Preparation Example 1 56 30 8 One 5 100 80 80 Comparative Production Example 2 86 - 8 One 5 100 80 80 Comparative Production Example 3 86 - 8 One 5 80 70 140 Comparative Production Example 4 51 35 8 5 One 80 70 138 Comparative Preparation Example 5 64 30 - 5 One 80 70 148 Comparative Preparation Example 6 39 30 25 5 One 80 70 135 Comparative Preparation Example 7 61 30 8 - One 80 70 132 Comparative Preparation Example 8 46 30 8 15 One 80 70 138 Comparative Preparation Example 9 57 30 8 5 - 80 70 137 Comparative Preparation Example 10 50 30 8 5 7 80 70 138 Comparative Production Example 11 56 30 8 5 One 120 80 80 BA: n-butyl acrylate
MA: methyl acrylate
BzMA: Benzyl methacrylate
AA: Acrylic acid
4-HBA: 4-hydroxybutyl acrylate
EAc: ethyl acetate

Example  1-10 and Comparative Example  1-11

1) Pressure-sensitive adhesive composition

The acrylic copolymer, the crosslinking agent, the silane coupling agent and the antistatic agent of Preparation Example 1 were mixed in the composition shown in Table 2, and then diluted to a concentration of 28% by weight in consideration of the coating property to prepare a pressure-sensitive adhesive composition.

division
(Parts by weight) Acrylic copolymer
(100 parts by weight) Cross-linking agent Silane coupling agent Antistatic agent A-1 A-2 A-3 A-4 B-1 B-2 Example 1 Production Example 1 0.5 - - - 0.5 2 - Example 2 Production Example 2 0.5 - - - 0.5 2 - Example 3 Production Example 3 0.5 - - - 0.5 2 - Example 4 Production Example 4 0.5 - - - 0.5 2 - Example 5 Production Example 5 0.5 - - - 0.5 2 - Example 6 Production Example 6 0.5 - - - 0.5 2 - Example 7 Production Example 1 - 0.5 - - 0.5 2 - Example 8 Production Example 1 - - 0.5 - 0.5 2 - Example 9 Production Example 1 - - - 0.5 0.5 2 - Example 10 Production Example 1 0.5 - - - 0.5 - 2 Comparative Example 1 Comparative Preparation Example 1 0.5 - - - 0.5 2 - Comparative Example 2 Comparative Production Example 2 0.5 - - - 0.5 2 - Comparative Example 3 Comparative Production Example 3 0.5 - - - 0.5 2 - Comparative Example 4 Comparative Production Example 4 0.5 - - - 0.5 2 - Comparative Example 5 Comparative Preparation Example 5 0.5 - - - 0.5 2 - Comparative Example 6 Comparative Preparation Example 6 0.5 - - - 0.5 2 - Comparative Example 7 Comparative Preparation Example 7 0.5 - - - 0.5 2 - Comparative Example 8 Comparative Preparation Example 8 0.5 - - - 0.5 2 - Comparative Example 9 Comparative Preparation Example 9 0.5 - - - 0.5 2 - Comparative Example 10 Comparative Preparation Example 10 0.5 - - - 0.5 2 - Comparative Example 11 Comparative Production Example 11 0.5 - - - 0.5 2 - A-1: Coronate-L (TDI crosslinking agent, CORONATE-L, Japan Urethane Industry)
A-2: Isocyanate art of TDI (Urethane Japan)
A-3: Coronate-HXR (isocyanurate of HDI, Urethane Company of Japan)
A-4: Takenate-110N (XDI crosslinking agent, TAKENATE-110N Mitsui Chemicals
Silane coupling agent: glycidoxypropyltrimethoxysilane (Shin-Etsu, KBM403)
B-1: Trifluoromethylsulfonylimide lithium salt
B-2: 1-Hexyl-4-methylpyridinium hexafluorophosphate

2) Polarizer with adhesive

1) was cured on a releasing film coated with a silicone release agent, and then coated to a thickness of 25 占 퐉 and dried at 100 占 폚 for 1 minute, 5 minutes and 10 minutes to form an adhesive layer.

A polarizing plate having a triacetyl cellulose protective film bonded to both sides of the polarizer was laminated on the pressure-sensitive adhesive layer to prepare a polarizing plate with a pressure-sensitive adhesive. At this time, the protective film surface and the adhesive layer were laminated so as to be in contact with each other. The prepared polarizing plate was stored for a curing period under the conditions of 23 캜 and 60% RH.

Further, a polarizing plate to which a polymethylmethacrylate protective film (water contact angle of 47 [deg.]) Was bonded in place of the triacetyl cellulose protective film (water contact angle of 12 [deg.]) Was laminated to prepare a polarizing plate with a pressure-sensitive adhesive.

Test Example

The physical properties of the polarizer with a pressure-sensitive adhesive prepared in the above Examples and Comparative Examples were measured by the following methods, and the results are shown in Table 3 below.

1. Curing period

The adhesive sheet thus prepared was cured for 1 to 10 days at 23 DEG C and 65% RH, and the gel fraction was measured in the following manner for each day, and the curing period was measured, in which the gel fraction was no longer increased.

Approximately 0.25 g of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet is attached to a wire mesh (100 mm x 100 mm) of a 250 mesh precisely weighed, and the gel is wrapped so as not to leak. After accurately weighing the weight with a precision balance, the wire net is immersed in the ethyl acetate solution for 3 days. The immersed wire mesh is taken out, washed with a small amount of ethyl acetate solution, dried at 120 ° C for 24 hours and then weighed. Using the measured weight, the gel fraction was calculated by the following equation (1). The curing period was determined on the basis of the time when the calculated gel fraction was included in the range of 70 to 80% and there was no change with time.

B is the weight of the wire netting attached to the pressure-sensitive adhesive layer (BA: weight of the pressure-sensitive adhesive, g); C is the weight of the wire netted after immersion (CA: weight of the gelled resin, g )being].

2. Durability (heat resistance, Wet heat )

The prepared polarizer with a pressure-sensitive adhesive was cut into a size of 90 mm × 170 mm, and the release film was peeled off. Then, the optical absorption axis was perpendicularly attached to both sides of the glass substrate (110 mm × 190 mm × 0.7 mm). At this time, the applied pressure was 5 kg / cm < 2 >, and the clean room operation was performed so that bubbles or foreign matter would not occur. The heat resistance characteristics were evaluated by observing the occurrence of bubbles or peeling after being left at a temperature of 80 ° C. for 1000 hours. The moisture resistance characteristics were evaluated by observing the occurrence of bubbles or peeling after being left at a temperature of 60 ° C. and 90% RH for 1000 hours Respectively. At this time, the sample was allowed to stand at room temperature for 24 hours immediately before evaluating the state of the specimen.

<Evaluation Criteria>

Ⓞ: No bubbles or peeling.

○: Bubbles or peeling <5

?: 5 pieces? Bubbles or peeling <10 pieces

X: 10 pieces &lt; bubble &

××: Bubbles or peeling in the front

3. Light resistance

In order to investigate the uniformity of light transmittance using the same specimen as above, it was observed whether light leakage occurred in the dark room using a backlight. As a method of testing the light transmission uniformity, a method of observing a coated polarized plate (200 mm x 200 mm) on both sides of a glass substrate (210 mm x 210 mm x 0.7 mm) at 90 degrees was adopted. The uniformity of light transmittance was evaluated according to the following criteria.

<Evaluation Criteria>

Ⓞ: Unevenness of light transmittance is difficult to judge with naked eyes

○: slight non-uniformity of light transmittance

?: Slight non-uniformity of light transmittance

X: There is a lot of non-uniformity of light transmittance

division Curing period durability Light resistance Heat resistance Wet heat Example 1 Triacetylcellulose 24h Ⓞ Ⓞ Ⓞ Polymethyl methacrylate 24h Ⓞ Ⓞ Ⓞ Example 2 Polymethyl methacrylate 24h ○ Ⓞ Ⓞ Example 3 Polymethyl methacrylate 24h ○ ○ Ⓞ Example 4 Polymethyl methacrylate 18h Ⓞ Ⓞ Ⓞ Example 5 Polymethyl methacrylate 12h Ⓞ ○ Ⓞ Example 6 Polymethyl methacrylate 24h Ⓞ Ⓞ ○ Example 7 Polymethyl methacrylate 18h Ⓞ Ⓞ Ⓞ Example 8 Polymethyl methacrylate 4 days ○ Ⓞ ○ Example 9 Polymethyl methacrylate 2 days ○ Ⓞ Ⓞ Example 10 Polymethyl methacrylate 24h ○ ○ Ⓞ Comparative Example 1 Triacetylcellulose 2 days △ ○ Ⓞ Polymethyl methacrylate 2 days × △ ○ Comparative Example 2 Triacetylcellulose 2 days × △ ○ Polymethyl methacrylate 2 days × × ○ Comparative Example 3 Triacetylcellulose 2 days △ ○ Ⓞ Polymethyl methacrylate 2 days × △ ○ Comparative Example 4 Triacetylcellulose 24h ○ × ○ Polymethyl methacrylate 24h △ × ○ Comparative Example 5 Triacetylcellulose 24h Ⓞ Ⓞ × Polymethyl methacrylate 24h ○ Ⓞ × Comparative Example 6 Triacetylcellulose 24h ○ × △ Polymethyl methacrylate 24h △ × × Comparative Example 7 Triacetylcellulose 10 days × ○ ○ Polymethyl methacrylate 10 days × △ Ⓞ Comparative Example 8 Triacetylcellulose 12h ○ × △ Polymethyl methacrylate 12h × × ○ Comparative Example 9 Triacetylcellulose 10 days ○ △ Ⓞ Polymethyl methacrylate 10 days ○ × ○ Comparative Example 10 Triacetylcellulose 12h ○ △ Ⓞ Polymethyl methacrylate 12h △ × ○ Comparative Example 11 Triacetylcellulose 24h ○ Ⓞ Ⓞ Polymethyl methacrylate 24h × △ Ⓞ

As shown in Table 3, the polarizing plates of Examples 1 to 10 using the pressure-sensitive adhesive composition containing specific components in a certain range according to the present invention maintained a curing period equal to or longer than that of Comparative Examples 1 to 11, and durability and light- And it was confirmed that it is much superior.

In particular, even when a polymethyl methacrylate film was used as a polarizer protective film, excellent durability and light-shielding properties were maintained.

Claims (10)

A polarizer protective film is bonded to at least one surface of the polarizer, and a pressure-sensitive adhesive layer containing the pressure-sensitive adhesive composition is formed on the polarizer protective film,
Wherein the polarizer protective film is polymethyl methacrylate,
The pressure-
47 to 76.5 parts by weight of a (meth) acrylate monomer having an alkyl group having 4 to 12 carbon atoms, 8 to 12 parts by weight of benzyl methacrylate, 0.5 to 3 parts by weight of 4-hydroxybutyl acrylate, 5 to 8 parts by weight of acrylic acid, And 10 to 30 parts by weight of methyl acrylate,
And an acrylic copolymer having a weight average molecular weight (in terms of polystyrene, Mw) of 1,000,000 or more.
The polarizing plate according to claim 1, wherein the weight average molecular weight is in the range of 1,000,000 to 2,000,000.
delete delete The polarizing plate according to claim 1, wherein the pressure-sensitive adhesive composition further contains a crosslinking agent.
delete delete delete The polarizing plate according to claim 1, wherein the polarizing plate is cut into a size of 90 mm × 170 mm, and the specimen having the optical absorption axes crossed on both sides of the glass substrate is left at a temperature of 80 ° C. for 1000 hours, Lt; RTI ID = 0.0 &gt; 5. &Lt; / RTI &gt;
The polarizing plate according to claim 1, wherein the polarizing plate is cut to a size of 90 mm × 170 mm, and the specimen attached to both sides of the glass substrate so that the optical absorption axes intersect with each other is left for 1000 hours under the condition of 60 ° C. and 90% RH Wherein the occurrence of bubbles or peeling is less than five.