KR101515671B1 - Adhesive composition - Google Patents

Abstract

The present invention relates to an adhesive composition. In the present invention, it is possible to provide an adhesive excellent in optical properties, such as transparency, capable of effectively attaching a functional film exhibiting hydrophobicity and moisture permeability to a polarizer. Further, the present invention can shorten the curing time of the adhesive composition and further effectively suppress the change with time of the adhesive. It is another object of the present invention to provide a composition capable of producing a polarizing plate through a pre-coating method as well as a conventional droplet method, and can easily adjust the thickness of the adhesive layer in the polarizing plate, And the fairness in the manufacturing process can be kept excellent.

Description

Adhesive composition [0001]

The present invention relates to an adhesive composition, an adhesive film, a method for producing the same, a polarizing plate, a manufacturing method thereof, and a liquid crystal display device.

A polarizing plate which is an optical component applied to a liquid crystal display device usually includes a protective film attached to one surface or both surfaces of the polarizer. The polarizing plate may have a structure in which a protective film is attached to one surface of the polarizer and the other surface thereof has a function of a protective film and an additional optical function.

In general, a polarizer is produced by treating a uniaxially stretched resin film dyed with a dichroic dye, mainly a polyvinyl alcohol film with boric acid, washing with water and drying, and then attaching a protective film.

As a protective film for a polarizer, triacetyl cellulose (TAC) film is mainly used, and it is attached to the polarizer through an aqueous polyvinyl alcohol-based adhesive or the like.

However, the triacetylcellulose film has a high moisture permeability and thus has a problem that the polarizing plate easily deteriorates under high temperature or high humidity conditions. Accordingly, there is an attempt to use a film having a lower moisture permeability than triacetylcellulose film, for example, a thermoplastic saturated norbornene resin film as a protective film (e.g., Patent Document 1). In addition, in addition to the above, it is possible to use an amorphous polyolefin film, a polyester resin film, an acrylic resin film, a polycarbonate resin film, a polysulfone resin film, an alicyclic polyimide resin film or a cyclic olefin (COP) Attempts to use it have also been made. However, when such a film is attached to a polarizer using an existing water-based adhesive or the like, sufficient adhesive strength can not be obtained, and properties such as water resistance and heat resistance deteriorate.

Japanese Patent Application Laid-Open No. 06-51117

An object of the present invention is to provide an adhesive composition, an adhesive film, a method for producing the same, a polarizing plate, a manufacturing method thereof, and a liquid crystal display device.

The present invention relates to an acrylic polymer composition comprising 100 parts by weight of an acrylic polymer; Not less than 5 parts by weight and not more than 30 parts by weight of an epoxy compound; And 0.3 to 3 parts by weight of a hydroxycarboxylic acid curing agent, and satisfies the following general formula (1).

[Formula 1]

P ≥ 1,500 gf / in

In the above general formula (1), P is obtained by laminating the cyclic olefin based resin film and the polarizing plate using the adhesive composition, and then peeling the cyclic olefin based resin at a stripping angle of 180 degrees at normal temperature and a stripping rate of 5 mm / Means the peeling force measured while peeling the film.

The adhesive composition of the present invention can be used, for example, as an adhesive composition for a polarizer. The term " adhesive composition for a polarizer " in the present invention means an adhesive composition used for attaching another optical film, for example, a protective film or an antireflection film, to a polarizer such as a polyvinyl alcohol- do.

The term " cationic photocurable adhesive composition " in the present invention means a composition which can be cured by cationic polymerization or cationic curing reaction induced by irradiation of electromagnetic waves. The categories of electromagnetic waves include microwaves, infrared (IR), ultraviolet (UV), X-rays and gamma rays as well as alpha particle beams, proton beams, neutron beams And a particle beam such as an electron beam.

In the present invention, it is possible to form the adhesive composition as a cationic photo-curable type, to maintain excellent storage stability of the composition, and to prevent deterioration and discoloration of the adhesive and the object to be bonded. Further, the curing speed can be sufficiently increased, the peeling force of the adhesive after curing can be kept high, and deformation of the adherend due to shrinkage during the curing process can be prevented.

Hereinafter, the adhesive composition of the present invention will be specifically described.

The adhesive composition of the present invention comprises an acrylic polymer. The kind of the acrylic polymer is not particularly limited as long as it can be used as a pressure-sensitive adhesive resin.

In the present invention, the acrylic polymer may have a weight average molecular weight (M _w ) of 100,000 or more. By keeping the weight average molecular weight of the polymer within the above range, the adhesive can exhibit excellent durability. In the present invention, the weight average molecular weight is a conversion value of standard polystyrene measured by GPC (Gel Permeation Chromatography). The upper limit of the weight average molecular weight of the acrylic polymer is not particularly limited, but can be maintained at about 3 million or less, preferably about 2.5 million or less, and more preferably about 2 million or less, in consideration of the coating property of the composition.

In the present invention, the acrylic polymer may be a polymer containing an alkyl (meth) acrylate and a copolymerizable monomer having a crosslinkable functional group in a polymerized form. In the present invention, the term " included in a polymerized form " means that the compound or monomer is included in a form such that it is inserted into the skeleton of the main chain or side chain of the polymer through polymerization reaction. In the present invention, it is particularly preferable to use, as the acrylic polymer, an acrylic polymer having a hydroxyl group, for example, a polymer comprising a polymerized form of a copolymerizable monomer having an alkyl (meth) acrylate and a hydroxyl group. It is not. The type of the alkyl (meth) acrylate contained in the polymerized form of the polymer is not particularly limited and, for example, an alkyl (meth) acrylate having an alkyl group having 1 to 14 carbon atoms in consideration of the glass transition temperature, Can be used. Examples of such alkyl (meth) acrylates include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) Butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 2-ethylbutyl (meth) acrylate, Acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, lauryl (meth) acrylate and tetradecyl But is not limited thereto.

In the present invention, the copolymerizable monomer having a crosslinkable functional group is a monomer having both a crosslinkable functional group and a copolymerizable functional group capable of being polymerized with the alkyl (meth) acrylate. Examples of such copolymerizable monomers include, but are not limited to, a hydroxyl group-containing copolymerizable monomer, a carboxyl group-containing copolymerizable monomer, and a nitrogen-containing copolymerizable monomer. Examples of the carboxyl group-containing copolymerizable monomers include (meth) acrylic acid, acrylic acid diesters, fumaric acid, itaconic acid, maleic acid and maleic anhydride; Examples of the nitrogen-containing copolymerizable monomer include (meth) acrylonitrile, (meth) acrylamide, N-methyl (meth) acrylamide, N-methylol (meth) acrylamide, N-vinylpyrrolidone, Caprolactam and the like; Examples of the hydroxyl group-containing copolymerizable monomers include glycerol (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (Meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyleneglycol (meth) acrylate, But are not limited thereto

The acrylic polymer of the present invention may include a copolymerizable monomer having a crosslinkable functional group in an amount of 1 to 20 parts by weight based on 100 parts by weight of the alkyl (meth) acrylate. In the present invention, properties such as adhesiveness, storage stability, and workability can be effectively controlled by controlling the weight ratio of each monomer as described above.

Unless otherwise specified, the unit " parts by weight " in the present specification means weight ratios.

From the viewpoints of controlling the glass transition temperature and imparting other functions, the acrylic polymer may be a styrenic monomer such as styrene or methylstyrene; Glycidyl (meth) acrylate; Or a functional comonomer such as a carboxylic acid vinyl ester such as vinyl acetate may be additionally contained in a polymerized form. In this case, the content of the functional comonomer is preferably 20 parts by weight or less, but is not limited thereto.

The adhesive composition of the present invention comprises an epoxy compound. The term " epoxy compound " in the present invention means a compound having at least one epoxy group in the molecule. In the above, the epoxy group may preferably be an epoxy group bonded to an alicyclic ring, i.e., an alicyclic epoxy group. In this case, the hydrogen atom constituting the alicyclic ring may be optionally substituted with a substituent such as an alkyl group.

The epoxy compounds usable in the present invention are specifically exemplified below, but the epoxy compounds usable in the present invention are not limited to the following types.

Examples of epoxy compounds usable in the present invention include epoxycyclohexylmethyl epoxycyclohexanecarboxylate compounds represented by the following general formula (1).

[Chemical Formula 1]

In Formula 1, R ₁ and R ₂ each independently represent hydrogen or an alkyl group.

Another example of the epoxy compound in the present invention is an epoxycyclohexanecarboxylate compound of an alkane diol represented by the following general formula (2).

(2)

In the formula (2), R ₃ and R ₄ each independently represent hydrogen or an alkyl group, and n represents an integer of 2 to 20.

Another example of the epoxy compound of the present invention is an epoxycyclohexylmethyl ester compound of dicarboxylic acid represented by the following general formula (3).

(3)

In the above formula (3), R ₅ and R ₆ each independently represent hydrogen or an alkyl group, and p represents an integer of 2 to 20.

Another example of the epoxy compound of the present invention is an epoxycyclohexyl methyl ether compound of polyethylene glycol represented by the following general formula (4).

[Chemical Formula 4]

In the formula (4), R ₇ and R ₈ each independently represent hydrogen or an alkyl group, and q represents an integer of 2 to 20.

Another example of the epoxy compound of the present invention is an epoxycyclohexyl methyl ether compound of an alkane diol represented by the following general formula (5).

[Chemical Formula 5]

In the formula (5), R ₉ and R ₁₀ each independently represent hydrogen or an alkyl group, and r represents an integer of 2 to 20.

Another example of the epoxy compound of the present invention is a diepoxy trispyrene compound represented by the following formula (6).

[Chemical Formula 6]

In Formula 6, R ₁₁ and R ₁₂ each independently represent hydrogen or an alkyl group.

Another example of the epoxy compound of the present invention is a diepoxy monosporo compound represented by the following general formula (7).

(7)

In Formula 7, R ₁₃ and R ₁₄ each independently represent hydrogen or an alkyl group.

Another example of the epoxy compound of the present invention includes a vinylcyclohexene diepoxide compound represented by the following general formula (8).

[Chemical Formula 8]

In Formula 8, R ₁₅ represents hydrogen or an alkyl group.

Another example of the epoxy compound of the present invention includes an epoxy cyclopentyl ether compound represented by the following general formula (9).

[Chemical Formula 9]

In the above formula (9), R ₁₆ and R ₁₇ each independently represent hydrogen or an alkyl group.

Another example of the epoxy compound of the present invention is a diepoxytricyclodecane compound represented by the following formula (10).

[Chemical formula 10]

In Formula 10, R ₁₈ represents hydrogen or an alkyl group.

In the definitions of the formulas (1) to (10), the alkyl group may mean a straight chain, branched or cyclic alkyl group having 1 to 20 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms or 1 to 4 carbon atoms.

In the present invention, an epoxy cyclohexylmethyl epoxycyclohexanecarboxylate compound, an epoxycyclohexanecarboxylate compound of an alkanediol, an epoxycyclohexylmethyl ester compound of a dicarboxylic acid, or an epoxycyclohexylmethyl ether compound of an alkanediol is used as the epoxy compound , And an esterified product of 7-oxabicyclo [4,1,0] heptane-3-carboxylic acid and (7-oxa-bicyclo [4,1,0] hept- Compounds wherein R < ₁ > and R < ₂ > are hydrogen in formula (1); Ester of 4-methyl-7-oxabicyclo [4,1,0] heptane-3-carboxylic acid with (4-methyl-7-oxa-bicyclo [ Cargo (in the formula 1, R ₁ is 4-CH ₃ and R ₂ is 4-CH ₃ ); An esterified product of 7-oxabicyclo [4,1,0] heptane-3-carboxylic acid and 1,2-ethanediol (in the above formula 2, R ₃ and R ₄ are hydrogen and n is 1); (7-oxabicyclo [4,1,0] hept-3-yl) methanol and adipic acid (compound of formula 3 wherein R ₅ and R ₆ are hydrogen and p is 2); (4-methyl-7-oxabicyclo [4,1,0] hept-3-yl) methanol and adipic acid (wherein R ₅ and R ₆ are 4-CH ₃ and p is 2); And ethers of (7-oxabicyclo [4,1,0] hept-3-yl) methanol and 1,2-ethanediol in which R ₉ and R ₁₀ are hydrogen and r is 1 ), But it is not limited thereto.

The adhesive composition of the present invention may contain 5 parts by weight or more and less than 30 parts by weight, preferably 5 parts by weight to 25 parts by weight, of the epoxy compound as described above relative to 100 parts by weight of the acrylic polymer And 5 parts by weight to 20 parts by weight. If the weight ratio of the epoxy compound is too low, the peeling force of the adhesive may be deteriorated. If the epoxy compound is too high, the processability and coating properties of the composition may deteriorate and the degree of curing may be excessively high, Since there is a risk of brittle, it is possible to adjust the appropriate content in consideration of this point.

The adhesive composition of the present invention includes a hydroxycarboxylic acid curing agent. In the present invention, the term " hydroxyl clock curing agent " means a compound containing at least one, preferably one to four, of hydroxy groups as functional groups capable of curing the adhesive composition of the present invention.

Examples of the curing agent usable in the present invention include aliphatic diols, polyether diols, polycarbonate diols, polycaprolactone diol polyester diols and polyol compounds.

As the aliphatic diol in the present invention, for example, a compound represented by the following formula (11) can be used.

(11)

In Formula 11, A represents a linear or branched alkylene.

In Formula 11, A may be, for example, a straight chain or branched alkylene having 1 to 20 carbon atoms, 1 to 12 carbon atoms, or 1 to 8 carbon atoms.

Examples of the diol compound of Formula 11 include 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 2-methyl- Methyl-1,5-pentanediol, and the like, but the present invention is not limited thereto.

As the polyether diol in the present invention, for example, a compound represented by the following formula (12) can be used.

[Chemical Formula 12]

In the above formula (12), X and Y each independently represents alkylene, and t represents an integer of 1 to 10.

In Formula 12, X and Y may be, for example, independently of each other a straight chain, branched or cyclic alkylene having 1 to 20 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms.

In the above formula (12), t may preferably represent 1 to 8, 1 to 6, or 1 to 4.

Examples of the compound of Formula 12 include di-, tri- or poly-ethylene glycol, di-, tri- or poly-propylene glycol, polytetramethylene glycol, polyhexamethylene glycol, polyheptamethylene glycol or polydecamethylene glycol , But are not limited thereto.

As the polycarbonate diol in the present invention, for example, a polycarbonate of polytetrahydrofuran, a polycarbonate of 1,6-hexanediol, or a polycarbonate diol represented by the following formula (13) may be used, Is preferably used.

[Chemical Formula 13]

Wherein Q and W each independently represent a divalent hydrocarbon group of 2 to 12 carbon atoms, U represents the same structure as Q or W, y represents an integer of 2 to 150, and z represents an integer of 0 to 150 Represents an integer, and y + z represents 2 to 200.

The polycarbonate diol represented by the above formula (13) can be produced, for example, by a known method such as ester exchange reaction of a diol compound and a carbonate compound or polycondensation reaction of a diol compound and phosgene. In this case, the diol compounds to be used include 1,4-butanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,9- Diol, and the like, but are not limited thereto.

In the present invention, as the polycaprolactone diol, for example, polycaprolactone diol obtained by reacting? -Caprolactone with a diol can be used. Examples of the diol in this case include ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, tetramethylene glycol, polytetramethylene glycol, 1,2-polybutylene glycol, 1,6-hexanediol, neopentyl glycol, 1,4-cyclohexane dimethanol, 1,4-butane diol and the like.

As the polyester diol in the present invention, for example, a polymer of an aliphatic diol compound and an aliphatic dicarboxylic acid compound can be used. In this case, as the aliphatic diol compound, for example, a diol compound of the above-mentioned formula (11) can be used. Examples of the aliphatic dicarboxylic acid compound include malonic acid, succinic acid, glutaric acid, adipic acid, .

In the present invention, the polyol compound may mean a compound having three or more hydroxy groups. Examples of the polyol compound include polyhydric alcohols such as trimethylolpropane, glycerin, pentaerythritol, sorbitol, sucrose, And a polyether polyol modified with a cyclic ether compound such as a radical (EO), propylene oxide (PO), butylene oxide or tetrahydrofuran. Specific examples thereof include EO-modified trimethylolpropane, PO- Modified EO-modified glycerin, tetrahydrofuran-modified glycerin, EO-modified pentaerythritol, PO-modified pentaerythritol, tetrahydrofuran-modified pentaerythritol, EO-modified Sorbitol, PO-modified sorbitol, EO-modified sucrose, PO-modified sucrose or EO-modified quadrolone. It is not limited.

In the present invention, an aliphatic diol or a polyether polyol may be preferably used among the above compounds, more preferably the polyether polyol represented by the above formula (12) may be used, but the present invention is not limited thereto.

The adhesive composition of the present invention may contain 0.3 to 3 parts by weight of the hydroxystyrene-based curing agent per 100 parts by weight of the acrylic polymer. Specifically, the hydroxyl group equivalent of the curing agent relative to 1 equivalent of the epoxy group of the epoxy compound is 0.001 equivalent To < RTI ID = 0.0 > 1 < / RTI > In the present invention, the content of the hydroxystyrene curing agent can be controlled as described above, whereby the workability and adhesive strength of the adhesive can be maintained to be excellent.

The adhesive composition of the present invention may further comprise a cationic polymerization initiator. The term " cationic polymerization initiator " in the present invention means a compound capable of initiating cationic polymerization by irradiation with electromagnetic waves or a compound capable of generating a compound capable of initiating cationic polymerization upon irradiation of electromagnetic waves.

The kind of the cationic polymerization initiator usable in the present invention is not particularly limited, and for example, a known cationic polymerization initiator such as an aromatic diazonium salt, an aromatic iodo aluminum salt, an aromatic sulfonium salt, or an iron- Among them, it is preferable to use an aromatic sulfonium salt, but it is not limited thereto.

The adhesive composition of the present invention may contain the cationic polymerization initiator in an amount of 0.01 to 10 parts by weight, preferably 0.1 to 3 parts by weight, based on 100 parts by weight of the epoxy compound. If the content of the cationic polymerization initiator in the present invention is too small, there is a fear that sufficient curing will not proceed. If the content is too large, the content of the ionic substance after curing will increase to increase the hygroscopicity of the adhesive, The conjugate acid is formed on the surface of the substrate, which is disadvantageous from the viewpoint of optical durability, and corrosion may occur depending on the substrate. Therefore, an appropriate content range can be selected in consideration of this point.

The adhesive composition of the present invention may further contain additives such as an ultraviolet stabilizer, an antioxidant, a colorant, a reinforcing agent, a filler, a defoaming agent, a surfactant, a photopolymerizable thickener and a plasticizer in addition to the above- May additionally include one or more species.

The adhesive composition of the present invention satisfies the relationship of the general formula (1). In the general formula (1), P is a peeling force measured while the cyclic olefin based resin film and the polarizing plate are laminated and adhered using the adhesive composition of the present invention, and peeling off the cyclic olefin based resin film.

In the present invention, the peeling force is specifically measured by the method described in the following examples. That is, in the present invention, by curing the composition with the above-mentioned specific components, it is possible to shorten the curing time of the composition and to prevent the change with time of the conventional adhesive composition, that is, the change of the peeling force with time, In addition, the peel strength can be maintained at a high level.

The upper limit of P in the general formula 1, i.e., the peeling force, is not particularly limited, and can be adjusted within a range of, for example, 5,000 gf / in or less.

The present invention also relates to an adhesive film for a polarizer having an adhesive layer comprising the above cationically curable adhesive composition of the present invention.

The adhesive composition of the present invention can be applied to a process of bonding a polarizer and a functional film such as a protective film after being prepared in the form of an adhesive film as described above. That is, the adhesive composition of the present invention can adhere the polarizer and the functional film not only by the conventional droplet method but also by the pre-coating method. As described above, since the polarizer and the protective film or other functional films can be attached by the precoating method, the thickness of the adhesive applied to the polarizing plate can be easily controlled, the uniformity thereof can be improved, Fairness can be maintained.

In the adhesive film of the present invention, the adhesive layer may contain the adhesive composition in a dried, hardened or semi-cured state, and preferably in a dried state. In the present invention, for example, a polarizer and a protective film or the like are laminated using an adhesive layer formed in a dried state as described above, and then the adhesive layer is irradiated with an electromagnetic wave to induce cation polymerization or curing, Can be prepared.

In the present invention, the thickness of the adhesive layer is not particularly limited and may be adjusted in consideration of the intended use.

The adhesive film of the present invention may further comprise a release sheet formed on the adhesive layer. In this case, the type of the releasable sheet that can be used is not particularly limited, and a releasable sheet commonly used in this field can be used.

The method for producing the adhesive film in the present invention is not particularly limited, and can be produced by employing a process commonly used in the production of an adhesive film. For example, the adhesive film of the present invention comprises a step of coating a release liquid of a release sheet with a coating solution containing the adhesive composition according to the present invention; And drying the coated coating liquid.

In the above method, the method of coating the coating liquid is not particularly limited, and for example, a conventional method such as bar coating may be used. Also, the drying conditions in the drying step are not particularly limited. For example, the drying step may be performed at a temperature of about 70 ° C to 130 ° C for about 1 minute to 10 minutes.

The present invention also relates to a polarizing element comprising: a polarizer; And an adhesive layer formed on one surface or both surfaces of the polarizer, the adhesive layer comprising the adhesive composition of the present invention in a cured state; And a protective film attached to the polarizer via the adhesive layer.

The kind of the polarizer included in the polarizing plate of the present invention is not particularly limited, and general types known in this field such as polyvinyl alcohol polarizers and the like can be employed without limitation.

A polarizer is a functional film or sheet capable of extracting only light vibrating in one direction from incident light while vibrating in various directions. The polarizer may be, for example, a form in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol-based resin film. The polyvinyl alcohol-based resin constituting the polarizer can be obtained by, for example, gelling a polyvinyl acetate-based resin. In this case, the polyvinyl acetate-based resin that can be used may include not only homopolymers of vinyl acetate but also copolymers of vinyl acetate and other comonomers copolymerizable therewith. Examples of the comonomer include, but are not limited to, one or more kinds of acrylamides having unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and ammonium groups. The degree of gelation of the polyvinyl alcohol-based resin is usually about 85 mol% to 100 mol%, preferably 98 mol% or more. The polyvinyl alcohol resin may be further modified. For example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. The degree of polymerization of the polyvinyl alcohol-based resin is usually about 1,000 to 10,000, preferably about 1,500 to 5,000.

The polyvinyl alcohol-based resin as described above can be formed and used as the original film of the polarizer. The method of forming the polyvinyl alcohol-based resin is not particularly limited, and a general method known in this field can be used. The thickness of the original film formed of a polyvinyl alcohol-based resin is not particularly limited, and can be suitably controlled within a range of, for example, 1 m to 150 m. The thickness of the original film can be controlled to 10 mu m or more in consideration of easiness of drawing and the like.

The polarizer may be a film obtained by stretching a polyvinyl alcohol-based resin film (e.g., uniaxial or biaxial stretching); Dyeing and adsorption of dichroic dye; Boric acid treatment; And a water washing step. As the dichroic dye, iodine or dichroic organic dyes may be used.

In the present invention, the kind of the protective film to be adhered to the one side or both sides of the polarizer by the adhesive of the present invention is not particularly limited.

Examples of the protective film that can be applied in the present invention include a cellulose film (ex, triacetyl cellulose (TAC)), amorphous polyolefin film, polyester resin film, acrylic resin film, polycarbonate resin film, A film such as a resin film, an alicyclic polyimide resin film, or a cyclic olefin (COP) resin film can be used. In the present invention, for example, when a protective film is adhered to both surfaces of a polarizer, at least one film may be formed of at least one of amorphous polyolefin film, polyester resin film, acrylic resin film, polycarbonate resin film, Film, an alicyclic polyimide-based resin film, or a cyclic olefin (COP) -based resin film, but the present invention is not limited thereto.

In the present invention, when a protective film is attached to both sides of the polarizer, the protective film may be the same kind or a different kind of film.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 and FIG. 2 are diagrams schematically showing a polarizing plate according to various examples of the present invention. 1, in the polarizing plate 1 of the present invention, a cellulose-based film 13 such as triacetylcellulose (TAC) is attached to one surface of a polarizer 11 by an adhesive 12a, On the other side, a film other than a cellulose-based film, for example, an acrylic film 14 or the like may be adhered by an adhesive 12b. In the present invention, as shown in Fig. 2, the polarizing plate 2 may have the protective films 14a and 14b of the same kind attached thereto on both sides of the polarizer 11 by the adhesives 12a and 12b of the present invention have. In this case, the protective films 14a and 14b are preferably selected from films other than the cellulose-based film. For example, an acrylic film or the like may be used.

The adhesive of the present invention can exhibit an excellent adhesive force even when the pretreatment using NaOH is not performed on a cellulose-based film such as triacetyl cellulose (TAC), which is commonly used as a protective film for existing polarizers, An amorphous polyolefin film, a polyester resin film, an acrylic resin film, a polycarbonate resin film, a polysulfone resin film, an alicyclic polyimide resin film, a polyimide resin film, It is possible to exhibit excellent adhesion even to a resin film or a cyclic olefin (COP) based resin film. As described above, since the adhesive composition of the present invention can apply the pre-coating method in the process of producing the polarizing plate, it is possible to easily adjust the thickness of the adhesive layer, maintain the uniformity of thickness, Can be kept excellent.

The method for producing the polarizing plate of the present invention as described above is not particularly limited in the present invention. For example, when the polarizing plate is manufactured by the above-described precoating method, the method comprises: laminating a polarizer and a protective film through an adhesive layer of the adhesive film of the present invention; And irradiating the adhesive layer with an electromagnetic wave to cure the adhesive layer.

The conditions for irradiating the adhesive layer with the electromagnetic wave in the above method of the present invention are not particularly limited. For example, the electromagnetic wave of the UV B region may be irradiated at a dose of about 500 mJ / cm ² to 1,500 mJ / cm ² and at 150 mW / cm ² To 400 mW / cm < ² >.

The present invention also provides a liquid crystal panel comprising: a liquid crystal panel; And a polarizing plate of the present invention attached to one or both surfaces of the liquid crystal panel.

The present invention also relates to a liquid crystal display including the liquid crystal panel in which the polarizing plate according to the present invention is attached to one surface or both surfaces thereof.

The kind of the liquid crystal panel included in the liquid crystal display device of the present invention as described above is not particularly limited. For example, the present invention is not limited to the type, and various types of F passive matrixes including Twisted Neumatic (TN) type, STN (Super Twisted Neumatic) type, F (ferroelectric) type, PD system; Various active matrix systems including two-terminal and three-terminal; Any known liquid crystal panel including a horizontal mode (IPS mode) panel and a vertical mode (VA mode) panel can be applied. Further, the other types of structures included in the liquid crystal display device of the present invention and the manufacturing method thereof are not particularly limited, and general structures in this field can be employed without any limitations.

In the present invention, it is possible to provide an adhesive excellent in optical properties, such as transparency, capable of effectively attaching a functional film exhibiting hydrophobicity and moisture permeability to a polarizer. Further, the present invention can shorten the curing time of the adhesive composition and further effectively suppress the change with time of the adhesive. It is another object of the present invention to provide a composition capable of producing a polarizing plate through a pre-coating method as well as a conventional droplet method, and can easily adjust the thickness of the adhesive layer in the polarizing plate, And the fairness in the manufacturing process can be kept excellent.

1 is a cross-sectional view schematically showing a polarizing plate according to one example of the present invention.
2 is a cross-sectional view schematically showing a polarizing plate according to one example of the present invention.

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

Manufacturing example  1. Preparation of acrylic polymer (A)

N-butyl acrylate (99 parts by weight) and hydroxybutyl acrylate (1 part by weight) were placed in a 1 L reactor equipped with a cooling device to easily regulate the temperature and nitrogen gas was refluxed. Subsequently, 120 parts by weight of ethyl acetate was added as a solvent, The oxygen was removed by purging with gas for 60 minutes. Subsequently, 0.1 part by weight of azobisisobutyronitrile as a reaction initiator was added, and the mixture was reacted for 6 hours. After completion of the reaction, the reaction mixture was diluted with ethyl acetate to give a solid concentration of 15.5% by weight, a weight average molecular weight of 1.7 million, (A) was about 7.0.

Example  One

Preparation of coating liquid

100 parts by weight of an acrylic polymer (A), 10 parts by weight of an epoxy compound (100% liquid epoxide, 7-oxa-bicyclo [4,1,0] hetan-3-ylmethyl 7-oxa-bicyclo [ 4,1,0] heptane-3-carboxylate, Celloxide 2021P, manufactured by DAICEL CO., LTD.) And an amount of tripropylene glycol (Aldrich) having a hydroxyl equivalent of 0.1 equivalent to 1 equivalent of the epoxy equivalent of the epoxy compound, , 0.3 parts by weight of an isocyanate-based adduct (T-39M manufactured by Soken Co., Ltd.) based on 1 part by weight of the cationic polymerization initiator (50 wt% propylene carbonate solution of triacrylsulfonium hexafluoroantimonate, Aldrich) ), And ethyl acetate (EAc) was added so that the solid content was maintained at 10 wt%. Thereafter, the mixture was mixed at 500 rpm for 20 minutes, and after mixing, the mixture was filtered by using 200 mesh or millet filter paper, and left to stand for defoaming.

Coating operation

The prepared mixture was coated on the release surface of a release PET film (MRL 38, thickness: 38 mu m) with a width of 25 cm and a thickness of 5 mu m, and was placed in three ovens whose temperatures were adjusted to 90 DEG C, 110 DEG C and 110 DEG C, respectively At a speed of 1 m / min and dried for a total of 4 minutes. After drying, another release type PET film (MRL 38, thickness: 23 mu m) was laminated on the coating liquid surface to form an adhesive film, and the film was wound. The rolled rolls were kept so that they were not exposed to visible light or fluorescent light until UV irradiation.

Production of Polarizer

The release PET film was removed from the adhesive film and laminated at room temperature under a pressure sufficient to allow complete adhesion with the cyclic olefin (COP) film. Thereafter, another mold releasing PET film was removed from the adhesive film, and the surface of the coating layer was laminated to a PVA polarizer. (B region, light quantity: 1,000 mJ / cm ² , illuminance: 210 mW / cm ² ) was applied to the COP film side by using a conveyer type lamp of a mercury light source after lamination.

Example  2

Except that the epoxy compound was blended in an amount of 20 parts by weight based on 100 parts by weight of the acrylic polymer (A).

Comparative Example  One

Epoxy compound (100% liquid epoxide, 7-oxa-bicyclo [4,1,0] hetan-3-ylmethyl 7-oxa-bicyclo [4,1,0] heptane-3-carboxylate, Celloxide 2021P, (Manufactured by Mitsubishi Rayon Co., Ltd.) in an amount of 30 parts by weight relative to the polymer (A).

Comparative Example  2.

A polarizing plate was produced in the same manner as in Example 1 except that the acrylic polymer was not used.

Comparative Example  3.

Epoxy compound (100% liquid epoxide, 7-oxa-bicyclo [4,1,0] hetan-3-ylmethyl 7-oxa-bicyclo [4,1,0] heptane-3-carboxylate, Celloxide 2021P, (Manufactured by Mitsubishi Rayon Co., Ltd.) was not used, the same procedure as in Example 1 was followed to prepare a polarizing plate.

The physical properties of the above Examples and Comparative Examples were evaluated in the following manner.

One. Coated  evaluation

The coating properties were evaluated according to the following criteria by observing the time of coating the coating liquid on the release PET film or the state of the coating layer after the coating in the manufacturing process of the adhesive films of Examples and Comparative Examples.

≪ Evaluation criteria of coating property &

○: When coating is progressing efficiently and appearance is good after coating

X: Efficient coating did not proceed, or poor appearance, bubble marks or haze occurred in the coating layer after coating

2. Evaluation of Fairness

The appearance and fibrillation of the coating layer were observed at the time of peeling off the release PET film from the adhesive films prepared in Examples and Comparative Examples and the fairness was evaluated according to the following criteria.

≪ Evaluation criteria of coating property &

○: No occurrence of fibrils and pinholes

Δ: Fibrils and pinholes occur in less than 5

X: More than 5 fibrils and pinholes occurred

3. Exfoliation  evaluation

On one side of the adhesive film produced in Examples and Comparative Examples, the release PET was peeled off and then attached to a ring-shaped olefin resin film (thickness: about 33 mu m, trade name: Jonoi Co., Ltd., manufactured by Nihon Zeon). Thereafter, the releasing PET on the other side of the adhesive film was peeled off, and a polarizing plate having a structure in which a TAC protective film was attached to both sides of a PVA polarizing plate (polyvinyl alcohol (PVA) polarizer, thickness: Manufactured by LG Chem Co., Ltd.) was laminated and a pressure of 5 kg / cm < ² > was applied for 1 second to 5 seconds so that the cyclic olefin resin film and the polarizer were completely pressed. Thereafter, the electromagnetic wave of the UV A region was cured on the adhesive layer from the side of the cyclic olefin resin film under conditions of 1,000 mJ / cm ² and 210 mW / cm ² . The resulting laminate was cut to a size of 15 cm × 2.5 cm (width × length) to prepare a specimen, and a cyclic olefin resin film was coated with a texture analyzer (Stable Micro System Ltd. (UK)) at room temperature The peel strength was measured while peeling off at a peel angle of 180 degrees and a peel rate of 5 mm / sec.

<Peel strength evaluation standard>

○: The peel strength measured was 1,500 gf / in or more

?: The peel strength measured was 1,000 gf / in or more and less than 1,500 gf / in

X: The peel strength measured was less than 1,000 gf / in

The measured results are summarized in Table 1 below.

Coating property Fairness Peel force Example 1 ○ ○ ○ Example 2 ○ ○ ○ Comparative Example 1 × × ○ Comparative Example 2 × △ × Comparative Example 3 ○ ○ ×

As can be seen from the above Table 1, Examples 1 and 2 according to the present invention exhibited excellent coating properties, fairness and peel strength, while Comparative Example 1 showed excellent coating properties and fairness And Comparative Examples 2 and 3 all exhibited a problem in the peeling force. In Comparative Example 2, on the other hand, the coating properties and the processability were poor.

1, 2: Polarizer 11: Polarizer
12a, 12b: Adhesive 13, 14, 14a, 14b: Protective film

Claims (16)

Acrylic polymers; An epoxy compound in an amount of 5 parts by weight or more and less than 30 parts by weight based on 100 parts by weight of the acrylic polymer; And a hydroxy clock curing agent in an amount of 0.3 part by weight to 3 parts by weight based on 100 parts by weight of the acrylic polymer, wherein the cationically curable adhesive composition satisfies the following general formula 1:
[Formula 1]
P ≥ 1,500 gf / in
In the above general formula (1), P is a film obtained by adhering a cyclic olefin resin film and a polyvinyl alcohol polarizer to the adhesive composition and peeling the cyclic olefin based resin film at a peeling angle of 180 degrees at normal temperature and a peeling rate of 5 mm / Quot; means the peeling force measured while peeling off. The cationic photocurable adhesive composition according to claim 1, wherein the acrylic polymer is an acrylic polymer having a hydroxy group. The epoxy resin composition according to claim 1, wherein the epoxy compound is selected from the group consisting of epoxy cyclohexylmethyl epoxycyclohexanecarboxylate compound, epoxycyclohexanecarboxylate compound of alkanediol, epoxycyclohexylmethyl ester compound of dicarboxylic acid, epoxycyclohexyl An epoxycyclohexylmethyl ether compound of an alkane diol, a diepoxy trispyiro compound, a diepoxy monospiro compound, a vinyl cyclohexene diepoxide compound, an epoxycyclopentyl ether compound or a diepoxy tricyclodecane compound &Lt; / RTI &gt; cationic photocurable adhesive composition. The method of claim 1, wherein the epoxy compound is selected from the group consisting of 7-oxabicyclo [4,1,0] heptane-3-carboxylic acid and (7-oxa-bicyclo [ &Lt; / RTI &gt; Ester of 4-methyl-7-oxabicyclo [4,1,0] heptane-3-carboxylic acid with (4-methyl-7-oxa-bicyclo [ freight; Esters of 7-oxabicyclo [4,1,0] heptane-3-carboxylic acid with 1,2-ethanediol; (7-oxabicyclo [4,1,0] hept-3-yl) methanol and adipic acid; (4-methyl-7-oxabicyclo [4,1,0] hept-3-yl) methanol and adipic acid; Or a (7-oxabicyclo [4,1,0] hept-3-yl) methanol and an ether of 1,2-ethanediol. The cationically curable adhesive composition of claim 1, wherein the hydroxystyrene curing agent is an aliphatic diol, a polyether diol, a polycarbonate diol, a polycaprolactone diol, a polyester diol, or a polyol compound. The cationic photocurable adhesive composition according to claim 5, wherein the aliphatic diol is represented by the following formula (11):
(11)

In Formula 11, A represents a linear or branched alkylene. The cationic photocurable adhesive composition according to claim 5, wherein the polyether diol is represented by the following formula (12):
[Chemical Formula 12]

In the above formula (12), X and Y each independently represents alkylene, and t represents an integer of 1 to 10. The cationic photocurable adhesive composition of claim 1, further comprising a cationic polymerization initiator. The cationic photocurable adhesive composition according to claim 8, wherein the cationic polymerization initiator is contained in an amount of 0.1 part by weight to 3 parts by weight based on 100 parts by weight of the epoxy compound. An adhesive film for a polarizer having an adhesive layer comprising the cationically curable adhesive composition according to claim 1. The polarizing adhesive film according to claim 10, further comprising a release sheet formed on the adhesive layer. Coating a release liquid of the release sheet with a coating solution containing the adhesive composition according to claim 1; And drying the coated coating liquid. A polarizer; And an adhesive layer formed on one or both surfaces of the polarizer, wherein the adhesive layer comprises the adhesive composition according to claim 1 in a cured state; And a protective film attached to the polarizer via the adhesive layer. The method according to claim 13, wherein the protective film is at least one selected from the group consisting of a cellulose film, amorphous polyolefin film, polyester resin film, acrylic resin film, polycarbonate resin film, polysulfone resin film, alicyclic polyimide resin film, A polarizer that is an olefin based resin film. Laminating a polarizer and a protective film through an adhesive layer of the adhesive film according to claim 10; And irradiating the adhesive layer with an electromagnetic wave to cure the polarizer. A liquid crystal panel; And a polarizer attached to one side or both sides of the liquid crystal panel.

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