KR20150059241A - Pressure sensitive adhesive composition - Google Patents

Abstract

The present invention relates to an adhesive composition, a protection film, an optical laminate, a polarization plate, and a display device. Provided in the present invention is an adhesive composition forming an adhesive which has excellent total properties such as durability reliability, and has conductivity, wherein the properties can be stably maintained for a long time. The adhesive composition for example can be used for an optical film such as a protection film and a polarization plate.

Description

[0001] PRESSURE SENSITIVE ADHESIVE COMPOSITION [0002]

The present invention relates to a pressure-sensitive adhesive composition, a protective film, an optical laminate, a polarizing plate and a display device.

The adhesive may be used in various applications. For example, the pressure-sensitive adhesive may be used in applications such as attaching an optical film such as a polarizing plate or a retardation film to a display device such as a liquid crystal display device (hereinafter referred to as " LCD device ") or an optical film And the like. As described above, the pressure-sensitive adhesives used for optical films and the like are required to have excellent transparency, cohesive strength, adhesive strength, reworkability, and low light leakage characteristics. For example, Patent Documents 1 to 3 propose an optical pressure-sensitive adhesive composition for optical properties to achieve the above properties.

In addition, if necessary, antistatic properties may be required for the pressure-sensitive adhesive, and for example, Patent Documents 4 and 5 disclose a pressure-sensitive adhesive that secures antistatic properties.

Patent Document 1: Korean Patent No. 1023839 Patent Document 2: Korean Patent No. 1171976 Patent Document 3: Korean Patent No. 1171977 Patent Document 4: JP-A-2009-173875 Patent Document 5: Korean Patent Publication No. 2008-0024215

The present application provides a pressure-sensitive adhesive composition, a protective film, an optical laminate, a polarizing plate and a display device.

Exemplary pressure sensitive adhesive compositions may include block copolymers. As used herein, the term " block copolymer " may refer to a copolymer comprising blocks of different polymerized monomers.

In one example, the block copolymer may include a first block having a glass transition temperature of 50 ° C or higher and a second block having a glass transition temperature of -10 ° C or lower. As used herein, the "glass transition temperature of a given block" of a block copolymer may refer to a glass transition temperature measured from a polymer formed only of the monomers contained in the block.

In one example, the glass transition temperature of the first block may be at least 60 ° C, at least 65 ° C, at least 70 ° C, or at least 75 ° C. In the present application, the upper limit of the glass transition temperature of the first block is not particularly limited and may be, for example, about 150 캜, 140 캜, 130 캜 or 120 캜.

On the other hand, the glass transition temperature of the second block may be, for example, -20 占 폚 or lower, -30 占 폚 or lower, -35 占 폚 or lower or -40 占 폚 or lower. In the present application, the lower limit of the glass transition temperature of the second block is not particularly limited and may be, for example, about -80 캜, -70 캜, -60 캜 or -55 캜.

A block copolymer containing at least two kinds of blocks each having a glass transition temperature falling within the above-mentioned range can form an appropriate fine phase-separated structure in the pressure-sensitive adhesive. The block copolymer in which the phase-separated structure is formed can form a pressure-sensitive adhesive which maintains excellent physical properties such as durability, light-shielding properties and reworkability by imparting appropriate cohesive force and stress relaxation property to the pressure-sensitive adhesive.

The first block in the block copolymer may have, for example, a number average molecular weight (Mn) of about 2,500 to 150,000. The number average molecular weight of the first block may mean, for example, the number average molecular weight of the polymer produced by polymerizing only the monomer forming the first block. The number average molecular weight referred to in the present specification can be measured by, for example, a method as shown in the examples using GPC (Gel Permeation Chromatograph). The number average molecular weight of the first block may be about 5,000 to 100,000 or 10,000 to 50,000 in another example.

The block copolymer may have a number average molecular weight of about 50,000 to 300,000. The number average molecular weight of the block copolymer may be in the range of 90,000 to 250,000, 90,000 to 200,000 or 90,000 to 180,000 in another example.

The block copolymer may also have a molecular weight distribution (PDI; Mw / Mn), that is, a ratio (Mw / Mn) of a weight average molecular weight (Mw) to a number average molecular weight (Mn) of about 1.0 to 2.5 or 1.4 to 2.5.

The block copolymer having the above properties can form a pressure-sensitive adhesive composition or pressure-sensitive adhesive having excellent physical properties.

In one example, the block copolymer may be a copolymer having a hydroxy group. The hydroxy group contained in the block copolymer improves the uniformity of the distribution of the antistatic agent contained in the pressure-sensitive adhesive composition and suppresses the change in antistatic performance even when the pressure-sensitive adhesive or the like is maintained for a long time under high temperature or high humidity conditions .

In one example, the hydroxy group may be included in a block having a relatively low glass transition temperature, for example, a second block. For example, when the hydroxy group is included in the second block, the uniformity of the distribution of the antistatic agent in the pressure-sensitive adhesive can be ensured while forming a pressure-sensitive adhesive excellent in endurance, light-shielding property and reworkability.

The kind of the monomer forming the first block and the second block in the block copolymer is not particularly limited as long as the glass transition temperature as described above can be ensured by the combination of the respective monomers.

In one example, the first block may comprise polymerized units derived from (meth) acrylic acid ester monomers. As used herein, the fact that a monomer is contained in a polymer or a block in a polymerized unit may mean that the monomer undergoes a polymerization reaction to form a skeleton of the polymer or block, for example, a main chain or a side chain. As the (meth) acrylic acid ester monomer, for example, alkyl (meth) acrylate can be used. (Meth) acrylates having an alkyl group of 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms in consideration of control of cohesion, glass transition temperature and tackiness . The alkyl group in the above may be, for example, straight chain, branched chain or cyclic. Examples of such monomers include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, (Meth) acrylate, n-butyl (meth) acrylate, sec-butyl (meth) acrylate, pentyl (Meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate and lauryl (meth) acrylate. Can be selected and used. The monomers forming the first block in consideration of the ease of controlling the glass transition temperature and the like include, but are not limited to, methacrylic acid ester monomers such as alkyl methacrylate and the like, for example, those having 1 to 20 carbon atoms, Alkyl methacrylates having 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms can be used.

The second block may include, for example, polymerized units derived from 60 to 99 parts by weight of a (meth) acrylic acid ester monomer and 1 to 40 parts by weight of a copolymerizable monomer having a hydroxyl group. In the present specification, the unit weight portion may mean the ratio of the weight between each component. For example, the fact that the second block contains polymerized units derived from 60 to 99 parts by weight of the (meth) acrylic acid ester monomer and 1 to 40 parts by weight of the copolymerizable monomer having a hydroxyl group means that Means a case where the ratio (A: B) based on the weight of the (meth) acrylic acid ester monomer (A) forming the polymerized unit and the copolymerizable monomer (B) having a hydroxy group is from 60 to 99: 1 to 40 can do. In one example, the second block may comprise polymerized units derived from 80 to 99 parts by weight of a (meth) acrylic acid ester monomer and 1 to 20 parts by weight of a copolymerizable monomer having a hydroxy group. Such a ratio range may be advantageous in providing a pressure-sensitive adhesive which ensures proper physical properties such as cohesive force and distribution uniformity of the antistatic agent.

As the (meth) acrylic acid ester monomer forming the second block, it is possible to secure a glass transition temperature in the above-described range finally through copolymerization with the copolymerizable monomer among the monomers that can be contained in the first block Type monomers can be selected and used. As the (meth) acrylic acid ester monomer forming the second block in consideration of the ease of controlling the glass transition temperature and the like, acrylic ester monomers such as alkyl acrylate and the like among the monomers described above, for example, those having 1 to 20 carbon atoms and 1 An alkyl acrylate having an alkyl group having 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms can be used.

The copolymerizable monomer having a hydroxy group can be used without particular limitation, for example, as long as it has a moiety copolymerizable with other monomers forming a block copolymer and also has a hydroxy group. Examples of the monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (Meth) acrylate such as hydroxyalkyl (meth) acrylate or 8-hydroxyoctyl (meth) acrylate or the like such as 2-hydroxyethyleneglycol (meth) acrylate or 2-hydroxypropyleneglycol (Meth) acrylate, and the like, but not limited thereto.

The second block may further comprise, if necessary, a crosslinkable functional group different from the above-mentioned hydroxy group. That is, in addition to securing the uniformity of the distribution of the antistatic agent, the hydroxy group may provide a cohesive force to the pressure-sensitive adhesive through a reaction with a polyfunctional crosslinking agent described later. In some cases, A crosslinking functional group other than a hydroxy group may be further included in the second block. For example, even when a crosslinkable functional group other than a hydroxy group is included, the crosslinkable functional group may not be included in the first block but may be contained only in the second block. Examples of such a crosslinkable functional group include a carboxyl group, an isocyanate group, and a glycidyl group. Such a functional group may be copolymerized by copolymerizing the monomer containing the functional group and the copolymerizable functional group during the production of the second block, and these monomers are variously known in the field of the production of the pressure-sensitive adhesive.

The first block and / or the second block may further comprise any other comonomer, if necessary, for example, for controlling the glass transition temperature and the like, and the monomer may be included as polymerized units have. Examples of the comonomer include (meth) acrylonitrile, (meth) acrylamide, N-methyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N-vinylpyrrolidone, Nitrogen-containing monomers such as lactam and the like; (Meth) acrylic acid esters, alkoxy alkylene glycol (meth) acrylic acid esters, alkoxy alkylene glycol (meth) acrylic acid esters, alkoxy alkylene glycol (Meth) acrylic acid esters, phenoxy alkylene glycol (meth) acrylic acid esters, phenoxy alkylene glycol (meth) acrylic acid esters, phenoxy trialkylene glycol Alkylene oxide group-containing monomers such as polyalkylene glycol (meth) acrylic acid esters and the like; Styrene-based monomers such as styrene or methylstyrene; Glycidyl group-containing monomers such as glycidyl (meth) acrylate; And carboxylic acid vinyl esters such as vinyl acetate, but are not limited thereto. These comonomers may be included in the polymer by selecting one kind or more than two types as appropriate according to need. Such comonomers may be included in the block copolymer, for example, in a proportion of 20 parts by weight or less, or 0.1 part by weight to 15 parts by weight, based on the weight of the other monomers in each block.

The block copolymer may comprise, for example, 5 to 50 parts by weight of the first block and 50 to 95 parts by weight of the second block. The ratio of the weight between the first block and the second block is adjusted as described above to provide the pressure-sensitive adhesive composition and the pressure-sensitive adhesive having excellent physical properties. In another example, the block copolymer comprises 5 to 45 parts by weight of the first block and 55 to 95 parts by weight of the second block or 5 to 45 parts by weight of the first block and 60 to 95 parts by weight of the second block. Parts by weight.

In one example, the block copolymer may be a diblock copolymer comprising first and second blocks, i.e. a block copolymer comprising only two blocks of the first and second blocks. By using the diblock copolymer, the durability of the pressure-sensitive adhesive, the stress relaxation property, and the reworkability can be maintained more excellent.

The method for producing the block copolymer is not particularly limited and can be produced by a conventional method. The block polymer is polymerized by, for example, an LRP (Living Radical Polymerization) method. Examples of the block polymer include an organic rare earth metal complex as a polymerization initiator or an organic alkali metal compound as a polymerization initiator to produce an alkali metal or alkaline earth metal Anion polymerization which is synthesized in the presence of an inorganic acid salt such as a salt, an anionic polymerization method in which an organic alkali metal compound is used as a polymerization initiator and synthesized in the presence of an organoaluminum compound, an atomic transfer radical polymerization (ATRP), Atomic Transfer Radical Polymerization (ATRP), ICAR (Initiators), etc., which perform polymerization under an organic or inorganic reducing agent that generates electrons using an atom transfer radical polymerization agent as a polymerization initiator for continuous activator regeneration) Atom Transfer Radical Polymerization (ATRP) (RAFT) using a reversible addition-cleavage chain transfer agent using a reducing agent addition-cleavage chain transfer agent, or a method using an organic tellurium compound as an initiator. Among these methods, an appropriate method can be selected and applied.

The pressure-sensitive adhesive composition may further include a crosslinking agent capable of crosslinking the block copolymer. The crosslinking agent is a compound having at least two functional groups capable of reacting with a hydroxyl group or the above-mentioned crosslinkable functional group, and various kinds of such compounds are well known. For example, as the crosslinking agent, an isocyanate crosslinking agent, an epoxy crosslinking agent, an aziridine crosslinking agent or a metal chelate crosslinking agent may be used, and for example, an isocyanate crosslinking agent may be used.

Examples of the isocyanate crosslinking agent include diisocyanate compounds such as tolylene diisocyanate, xylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isoboron diisocyanate, tetramethylxylene diisocyanate and naphthalene diisocyanate, Or a compound obtained by reacting the diisocyanate compound with a polyol can be used. As the polyol, for example, trimethylolpropane and the like can be used.

The pressure-sensitive adhesive composition may contain one or more of the above-mentioned crosslinking agents, but the crosslinking agents that can be used are not limited thereto.

The multifunctional crosslinking agent may be used in an amount of 0.01 to 20 parts by weight, 0.01 to 15 parts by weight, 0.01 to 10 parts by weight or 0.01 to 5 parts by weight based on 100 parts by weight of the block copolymer, And the gel fraction, cohesive force, adhesive force, durability, etc. of the pressure-sensitive adhesive can be excellently maintained in this range.

The pressure-sensitive adhesive composition may further comprise an antistatic agent. As the antistatic agent, for example, an ionic compound may be used. As the ionic compound, an organic salt or an inorganic salt can be exemplified.

As the inorganic salt, for example, a metal salt containing a metal ion as a cation may be used. The metal salt may include, for example, an alkali metal cation or an alkaline earth metal cation. Examples of the cation include lithium ion (Li ⁺ ), sodium ion (Na ⁺ ), potassium ion (K ⁺ ), rubidium ion (Rb ⁺ ), cesium ion (Cs ⁺ ), beryllium ion (Be ²⁺ ) ⁺⁾ and calcium ions (Ca ^{2 +),} strontium ion (Sr ^{2 +)} and barium ion (Ba ^{2 +),} there is iljong or two kinds or more of the like can be illustrated, for example, a lithium ion, a sodium ion, a potassium ion , A lithium ion can be used in consideration of one or more kinds of magnesium ion, calcium ion and barium ion, or ion stability and mobility.

As the organic salt, for example, an ionic compound containing an organic cation can be used. As the organic cation, an onium cation can be exemplified. The term onium cation as used herein refers to a positive charged ion comprising a structure in which at least some of the charge is localized to atoms such as nitrogen (N), phosphorus (P) and / or sulfur (S) can do. The onium cation may be a cyclic or non-cyclic compound, and when cyclic, it may be an aromatic or non-aromatic compound. The onium cation may further comprise other atoms such as oxygen or carbon atoms in addition to the nitrogen, phosphorus and / or sulfur. The onium cation may optionally be substituted by a substituent such as a halogen, an alkyl group or an aryl group. For example, the acyclic compound may include one or more substituents, which may be cyclic or acyclic substituents, aromatic or nonaromatic substituents.

Examples of the onium cation include N, N-dimethyl N-propylammonium, N, N, N-trimethyl-N-propylammonium, N-methyl- , N-ethyl-N, N, N-tributylammonium, N-methyl-N, N, N-trihexylammonium, , N-trioctylammonium or N-ethyl-N, N, N-trioctylammonium and the like, phosphonium, pyrolidinium) or piperidinium, and the like.

Examples of anions included in the ionic compounds such as inorganic salts and organic salts include PF ₆ ^- , AsF ^- , NO 2 ^- , fluoride (F ^- ), chloride (Cl ^- ), bromide (Br ^- ), iodide ^- ), perchlorate (ClO ₄ ^- ), hydroxide (OH ^- ), carbonate (CO ₃ ^{2 -} ), nitrate (NO ₃ ^- ), trifluoromethanesulfonate (CF ₃ SO ₃ ^- (SO ₄ ^-), phosphate (PF ₆ ^-) hexafluoropropane, methyl benzene sulfonate _{(CH 3 (C 6 H 4} ) SO 3 -), p- toluenesulfonate _{(CH 3 C 6 H 4 SO} 3 -) , tetraborate (B ₄ O ₇ ^2-), carboxymethyl sulfonate _{(COOH (C 6 H 4)} SO 3 -), sulfonate to flow (CF ₃ SO ₂ ^-), benzo carbonate (C ₆ H ₅ COO ^-), acetate (CH ₃ COO ^-), a triple acetate (CF ₃ COO ^-), borates (BF ₄ ^{tetrafluoro-),} tetra-benzyl borate _{(B (C 6 H 5)} 4 -) or tris-pentafluoropropane (P (C ₂ F ₅ ) ₃ F ₃ ^- ) and the like can be exemplified have.

In another example, the anion may be an anion or bifluorosulfonylimide represented by the following formula (1), or the like.

[Chemical Formula 1]

[X (YO _m R _f ) _n ] ^-

X is a nitrogen atom or a carbon atom, Y is a carbon atom or a sulfur atom, R _f is a perfluoroalkyl group, m is 1 or 2, and n is 2 or 3.

When Y is carbon in Formula (1), m is 1, and when Y is sulfur, m is 2, n is 2 when X is nitrogen, and n is 3 when X is carbon.

The anion or bis (fluorosulfonyl) imide of formula (1) exhibits high electronegativity due to the perfluoroalkyl group (R _f ) or the fluorine group and also forms a weak bond with the cation, including a unique resonance structure And at the same time has hydrophobicity. Therefore, the ionic compound exhibits excellent compatibility with other components of the composition such as a polymer, and can give a high antistatic property even in a small amount.

R _f in formula (1) may be a perfluoroalkyl group having 1 to 20 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms, wherein the perfluoroalkyl group may be a linear, branched or cyclic Structure. The anion of formula (1) may be a sulfonylimide-based, sulfonylimide-based, carbonylimide-based or carbonylimide-based anion, and specifically includes tris trifluoromethanesulfonylmethide, bistrifluoromethanesulfonyl A perfluorobutanesulfonylimide, bispentafluoroethanesulfonylimide, tris trifluoromethanecarbonylmide, bis perfluorobutanecarbonylimide or bispentafluoroethanecarbonyl, bispentafluoroethanesulfonylimide, bis Imide, etc., or a mixture of two or more species.

The ratio of the antistatic agent may be adjusted in consideration of the desired antistatic property. In one example, 0.01 to 20 parts by weight, 0.01 to 15 parts by weight, and 0.01 part by weight, relative to 100 parts by weight of the block copolymer, To 10 parts by weight, 0.01 to 5 parts by weight, 0.01 to 3 parts by weight, or 0.1 to 3 parts by weight, based on the weight of the composition.

The pressure-sensitive adhesive composition may further include a silane coupling agent. As the silane coupling agent, for example, a silane coupling agent having a beta-cyano group or an acetoacetyl group can be used. Such a silane coupling agent can be used, for example, so that a pressure-sensitive adhesive formed by a copolymer having a low molecular weight can exhibit excellent adhesion and adhesive stability, and can maintain excellent durability reliability under heat and moisture and heat have.

As the silane coupling agent having a beta-cyano group or an acetoacetyl group, for example, a compound represented by the following formula (2) or (3) can be used.

 (2)

(R ₁ ) _n Si (R ₂ ) _(4-n)

 (3)

(R ₃ ) _n Si (R ₂ ) _(4-n)

In formula 2 or 3, R ₁ is a beta-cyano-acetyl or beta-and cyano-acetyl group, R ₃ is acetonitrile, and an acetyl group or an acetoacetyl group, R ₂ is an alkoxy group, n is from 1 to 3 Number.

In the general formula (2) or (3), the alkyl group may be an alkyl group having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms or 1 to 4 carbon atoms, and the alkyl group may be linear, branched or cyclic have. In the general formula (2) or (3), the alkoxy group may be an alkoxy group having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms or 1 to 4 carbon atoms, and the alkoxy group may be a straight chain, Can be.

Further, in the general formula (2) or (3), n may be, for example, 1 to 3, 1 to 2 or 1.

As the compound of the formula (2) or (3), for example, acetoacetylpropyltrimethoxysilane, acetoacetylpropyltriethoxysilane, beta-cyanoacetylpropyltrimethoxysilane or beta-cyanoacetylpropyltriethoxysilane , But are not limited thereto.

In the pressure-sensitive adhesive composition, the silane coupling agent may be contained in an amount of 0.01 to 5 parts by weight or 0.01 to 1 part by weight based on 100 parts by weight of the block copolymer, and the desired physical properties may be effectively imparted to the pressure-sensitive adhesive within this range.

The pressure-sensitive adhesive composition may further comprise, if necessary, a tackifier. Examples of the tackifier include a hydrocarbon resin or hydrogenated product thereof, a rosin resin or hydrogenated product thereof, a rosin ester resin or hydrogenated product thereof, a terpene resin or hydrogenated product thereof, a terpene phenol resin or hydrogenated product thereof, Polymerized rosin ester resin, and the like, or a mixture of two or more of them may be used, but the present invention is not limited thereto. The tackifier may be included in the pressure-sensitive adhesive composition in an amount of 100 parts by weight or less based on 100 parts by weight of the block copolymer.

The pressure-sensitive adhesive composition may contain one or more compounds selected from the group consisting of a coordinating compound capable of forming a coordination bond with an antistatic agent, an epoxy resin, a curing agent, a UV stabilizer, an antioxidant, a colorant, a reinforcing agent, a filler, a defoamer, a surfactant and a plasticizer The above additives may further be included.

The pressure-sensitive adhesive composition can be used in various applications. Typical applications include, but are not limited to, application to a protective film or optical film described below.

The present application is also directed to a protective film. The protective film can be used, for example, for protecting the surface of various optical films.

Examples of the optical film include a polarizing plate, a polarizer, a polarizer protective film, a retardation film, a viewing angle compensation film, and a brightness enhancement film, but the present invention is not limited thereto. As used herein, the term polarizer and polarizer refers to objects that are distinguished from each other. That is, the polarizer refers to a film, sheet or device itself exhibiting a polarization function, and the polarizer refers to an optical element including other elements together with the polarizer. Other elements that can be included in the optical element together with the polarizer include, but are not limited to, a polarizer protective film or a retardation layer.

The protective film may include, for example, a protective substrate layer and a pressure-sensitive adhesive layer on one or both surfaces of the substrate layer. The pressure-sensitive adhesive layer may include, for example, the pressure-sensitive adhesive composition described above. The pressure-sensitive adhesive composition may be contained in the pressure-sensitive adhesive layer, for example, in a crosslinked state, that is, a state in which a crosslinked structure is realized.

As the protective substrate layer, a general film or sheet known in this field can be used. For example, a polyester film such as polyethylene terephthalate or polybutylene terephthalate, a polytetrafluoroethylene film, a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a poly (vinyl chloride) film or a polyimide film And the like. Such a film may be composed of a single layer, or two or more layers may be laminated, and in some cases, a functional layer such as an antifouling layer may be further included. From the viewpoint of improving the adhesion of the substrate, a surface treatment such as a primer treatment may be performed on one surface or both surfaces of the substrate.

The thickness of the base layer is not particularly limited and may be suitably selected according to the application, and it may be usually formed to a thickness of 5 to 500 탆 or 10 to 100 탆.

The thickness of the pressure-sensitive adhesive layer included in the protective film is not particularly limited, and may be, for example, 2 占 퐉 to 100 占 퐉 or 5 占 퐉 to 50 占 퐉.

The pressure-sensitive adhesive composition may be used for an optical film. For the optical film, for example, a polarizing plate, a polarizer, a retardation film, an anti-glare film, a wide viewing angle compensation film, or a brightness enhancement film are laminated to each other, or the optical film or its laminate is adhered to an adherend such as a liquid crystal panel For example.

That is, the present application is also directed to a pressure-sensitive adhesive optical laminate. Exemplary optical stacks include optical films; And a pressure-sensitive adhesive layer formed on one side or both sides of the optical film. The pressure-sensitive adhesive layer may be, for example, for adhering the optical film to a liquid crystal panel or other optical film of an LCD device, or for laminating another optical film to the laminate. The pressure-sensitive adhesive layer may comprise the above pressure-sensitive adhesive composition. The pressure-sensitive adhesive composition may, for example, be contained in the pressure-sensitive adhesive layer in a state of realizing a crosslinked structure. Examples of the optical film include a polarizer, a retardation film, a brightness enhancement film, and a laminate in which two or more of the above are laminated.

The present application also relates to an adhesive polarizing plate. The polarizing plate may have, for example, a structure in which the optical film is a polarizer in the adhesive optical laminate.

The type of the polarizer included in the polarizing plate is not particularly limited, and for example, general types known in this field such as a polyvinyl alcohol polarizer and the like can be employed without limitation.

A polarizer is a functional film capable of extracting only light vibrating in one direction from incident light while vibrating in various directions. Such a 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 monomers copolymerizable therewith. Examples of the monomer copolymerizable with vinyl acetate include monomers such as unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having an ammonium group, or a mixture of two or more thereof. no. The degree of gelation of the polyvinyl alcohol-based resin may be generally from 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 may be about 1,000 to 10,000 or about 1,500 to 5,000.

The polarizer is formed by a process of stretching a polyvinyl alcohol-based resin film as described above (e.g., uniaxial stretching), dyeing a polyvinyl alcohol-based resin film with a dichroic dye and adsorbing the dichroic dye, A process of treating a polyvinyl alcohol resin film with a boric acid aqueous solution and a process of washing with a boric acid aqueous solution after washing. As the dichroic dye, iodine or dichroic organic dyes may be used.

The polarizing plate may further include a protective film attached to one side or both sides of the polarizer. In this case, the pressure sensitive adhesive layer may be formed on one side of the protective film. The kind of the protective film is not particularly limited and includes, for example, a cellulose-based film such as TAC (triacetyl cellulose); Polycarbonate film or PET (poly (ethylene terephthalate)); Polyethersulfone-based films; Or a polyolefin film produced by using a polyethylene film, a polypropylene film, a resin having a cyclo or norbornene structure, or an ethylene-propylene copolymer, or the like, or a film having a laminate structure of two or more layers.

The polarizing plate may further include at least one functional layer selected from the group consisting of a protective layer, a reflective layer, an antiglare layer, a retardation film, a wide view angle compensation film, and a brightness enhancement film.

The method for forming the pressure-sensitive adhesive layer on the protective film, the polarizing plate or the optical film in the present application is not particularly limited. For example, the pressure-sensitive adhesive composition may be directly coated and cured to form a crosslinked structure, And a method of forming a crosslinked structure by coating and curing the pressure-sensitive adhesive composition on the release-treated surface of the pressure-sensitive adhesive composition, followed by transferring the crosslinked structure.

The method of coating the pressure-sensitive adhesive composition is not particularly limited. For example, a method of applying the pressure-sensitive adhesive composition by a common means such as a bar coater may be used.

The multifunctional crosslinking agent contained in the pressure-sensitive adhesive composition during the coating process is preferably controlled in such a manner that the crosslinking reaction of the functional groups does not proceed from the viewpoint of performing a uniform coating process. Thus, the crosslinking agent can be crosslinked Structure to improve the cohesive force of the pressure-sensitive adhesive, and improve the adhesive property and cuttability.

The coating process is also preferably performed after sufficiently removing the bubble-inducing component such as volatile components or reaction residues in the pressure-sensitive adhesive composition, and thus the crosslinking density or the molecular weight of the pressure-sensitive adhesive is too low to lower the elastic modulus, It is possible to prevent the problem that the bubbles existing between the glass plate and the adhesive layer become large and scatterers are formed inside.

The method of curing the pressure-sensitive adhesive composition to realize a crosslinked structure is not particularly limited. For example, a method of maintaining the coating layer at a proper temperature so that a crosslinking reaction between the block copolymer contained in the coating layer and the multi- And the like.

The present application is also directed to a display device, for example, an LCD device. Mentioned exemplary optical laminate or polarizing plate. When the display device is an LCD, the device may include a liquid crystal panel and the polarizing plate or optical laminate attached to one or both sides of the liquid crystal panel. The polarizing plate or the optical laminate may be attached to the liquid crystal panel by the above-described pressure-sensitive adhesive. Examples of the liquid crystal panel to be applied to the LCD include passive matrix type panels such as TN (twisted nematic) type, STN (super twisted nematic) type, F (ferroelectic) type or PD (polymer dispersed) type; An active matrix type panel such as a two terminal or a three terminal type; A known panel such as an in-plane switching (IPS) panel and a vertical alignment (VA) panel may be used.

Other configurations of the display device, for example, types of upper and lower substrates such as a color filter substrate or an array substrate in an LCD are not particularly limited, and configurations known in this field can be employed without limitation.

The present application can provide a pressure-sensitive adhesive composition which is excellent in various physical properties such as durability and reliability and can form a pressure-sensitive adhesive which has conductivity and can stably maintain the physical properties for a long time. The pressure-sensitive adhesive composition can be used for optical films such as protective films, polarizing plates and the like.

Hereinafter, the pressure-sensitive adhesive composition will be described in detail by way of examples and comparative examples, but the scope of the pressure-sensitive adhesive composition is not limited by the following examples.

The physical properties of the present examples and comparative examples were evaluated in the following manner.

1. Evaluation of molecular weight characteristics

The number average molecular weight (Mn) and the molecular weight distribution (PDI) of the copolymer were measured using GPC (Gel Permeation Chromatography), and the measurement conditions of GPC were as follows. The calibration curve was prepared using standard polystyrene (Aglient system).

≪ GPC measurement condition >

Measurer: Aglient GPC (Aglient 1200 series, U.S.)

Column: Two PL Mixed B connections

Column temperature: 40 ° C

Eluent: THF (Tetrahydrofuran)

Flow rate: 1.0 mL / min

Concentration: ~ 1 mg / mL (100 [mu] l injection)

2. Surface resistance evaluation

The surface resistivity was evaluated according to the following procedure under the following conditions.

<Measurement Conditions>

Measuring instrument: Hiresta-UP (MCP-HT 450, Mitsubishi chemical)

Probe: URS

Voltage: 500V

<Measurement procedure>

1) The polarizing plates prepared in Examples and Comparative Examples were cut to a length of 5 cm and a length of 5 cm.

2) Measure the surface resistance of the cut sample (initial).

3) The polarizing plate having the surface resistance measured in the step 2) is allowed to stand at 80 DEG C for 7 days, and then the surface resistance is again measured (heat resistance, 7 days).

4) The polarizing plate having the surface resistance measured in step 2) is allowed to stand for 7 days at 60 ° C and 90% relative humidity, and the surface resistance is again measured (wet heat resistance, 7 days).

3. Evaluation of durability

The polarizing plates prepared in Examples and Comparative Examples were cut to have a width of about 180 mm and a length of about 320 mm, and they were attached to a commercially available liquid crystal panel of 19 inches. Thereafter, the liquid crystal panel with the polarizer attached thereto is stored in an autoclave (50 DEG C, 5 atm) for about 20 minutes to prepare a sample. The durability against moisture and heat of the prepared sample was evaluated by observing the occurrence of bubbles and peeling at the adhesive interface after the sample was left at 60 ° C and 90% relative humidity for 500 hours. The durability was evaluated by the following criteria: Lt; [deg.] &Gt; C for 500 hours, the occurrence of air bubbles and peeling was observed and evaluated according to the following criteria.

<Evaluation Criteria>

A: No bubbles and peeling occurred

B: Bubbles and / or slight peeling occurred

C: large amount of bubbles and / or peeling occurred

4. Glass transition temperature

The glass transition temperature (Tg) of each block of the block copolymer or the block copolymer was calculated according to the following equation (A).

&Lt; Formula A >

1 / Tg =? Wn / Tn

In the formula A, Wn is the weight fraction of the monomer applied to each block of the block copolymer or the copolymer, and Tn is the glass transition temperature when each of the monomers forms a homopolymer. That is, in the formula (A), the value obtained by dividing the weight fraction of the used monomers by the glass transition temperature (Wn / Tn) obtained when the monomers are formed into the homopolymer is calculated for each monomer to be.

Manufacturing example  1. Preparation of block copolymer (A1)

0.22 g of ethyl 2-bromoisobutyrate, 60 g of methyl methacrylate (MMA) and 40 g of butyl methacrylate (BMA) were mixed in 39.5 g of ethyl acetate (EAc). The flask containing the mixture was sealed with a rubber membrane, subjected to nitrogen purging and stirring at about 25 캜 for about 30 minutes, and dissolved oxygen was removed through bubbling. Thereafter, 0.016 g of CuBr ₂ , 0.042 g of TPMA (tris (2-pyridylmethyl) amine) and 0.018 g of V-65 (2,2'-azobis (2,4-dimethyl valeronitrile) And the reaction was initiated by immersing in a reaction tank at about 67 ° C (polymerization of the first block). A mixture of 1212 g of butyl acrylate (BA) previously bubbled with nitrogen, 37 g of hydroxybutyl acrylate (HBA) and 677.5 g of ethyl acetate (EAc) was added to the mixture at a time when the conversion of methyl methacrylate was about 75% . &Lt; / RTI &gt; Then, 0.049 g of CuBr _2, 0.099 g of TPMA and 0.115 g of V-65 were added to the reaction flask, and chain extension reaction was carried out (polymerization of the second block). When the conversion of the monomer (BA) reaches 80% or more, the reaction mixture is exposed to oxygen, diluted with an appropriate solvent, and the reaction is terminated to prepare a block copolymer (in the above process, V- The reaction mixture was appropriately divided and added until the end of the reaction.)

Manufacturing example  2 to 5. Preparation of block copolymers (A2, A3, B1 and B2)

A block copolymer was prepared in the same manner as in Preparation Example 1, except that the raw materials used in the polymerization of the first block and the second block were adjusted in the ratio shown in Table 1 below.

Block copolymer A1 A2 A3 B1 B2 The first block MMA  ratio 60 70 80 70 20 BMA  ratio 40 30 20 20 80 HPMA  ratio 0 0 0 10 0 Tg (° C) 72 80 90 81 41 Mn (x10000) 2.9 2.7 2.3 2.3 2.3 PDI 1.38 1.36 1.34 1.36 1.39 The second block BA  ratio 97.0 90.0 80.0 100.0 97.0 HBA  ratio 3.0 10.0 20.0 0.0 3.0 Tg (° C) -46.2 -49.1 -53.0 -45 -46.2 block
Copolymer Mn (x10000) 12.3 15.6 17.8 12.4 12.2 PDI 1.8 2.3 2.4 1.8 1.8 The first block
: Second block
(Weight ratio) 10.1: 89.9 10.1: 89.9 10.1: 89.9 10.1: 89.9 10.1: 89.9 Monomer ratio Unit: Weight portion
BA : butyl acrylate (Homopolymer Tg : About -45 ° C)
HBA : 4- hydroxybutyl acrylate (Homopolymer Tg : About -80 ° C)
MMA : methyl 메록acrylate (Homopolymer Tg : About 110 ° C)
BMA : butyl 메록acrylate (Homopolymer Tg : About 27 ° C)
HPMA :2- hydroxypropyl 메록acrylate (Homopolymer Tg : About 26 ° C)
Tg : Glass transition temperature
Mn : Number average molecular weight
PDI : Molecular weight distribution

Manufacturing example  6. Preparation of random copolymer (B3)

10 parts by weight of methyl methacrylate (MMA), 87.3 parts by weight of n-butyl acrylate, and 2.7 parts by weight of 4-hydroxybutyl acrylate were charged into a 1 L reactor equipped with a cooling device to easily regulate the temperature and nitrogen gas was refluxed And 200 parts by weight of n-dodecylmercaptanol as a molecular weight regulator, and 120 parts by weight of ethyl acetate as a solvent were added. Next, nitrogen gas was purged for about 60 minutes to remove oxygen, 0.05 parts by weight of AIBN (azobisisobutyronitrile) as a reaction initiator was added while maintaining the temperature at 60 占 폚, and the reaction was carried out for about 8 hours to prepare a random copolymer. The number average molecular weight (Mn) of the prepared random copolymer (B3) was about 132,000 and the molecular weight distribution (PDI) was about 4.6.

Example  One.

Preparation of coating liquid (pressure-sensitive adhesive composition)

0.07 part by weight of a crosslinking agent (Coronate L, manufactured by NPU, Japan), 0.1 part by weight of DBTDL (Dibutyltin dilaurate), 0.1 part by weight of an antistatic agent (LiTFSi: Lithium trifluorosulfonylimide) And 0.2 parts by weight of a silane coupling agent having a nonoacetyl group were mixed, and ethyl acetate was mixed as a solvent to prepare a coating liquid (pressure-sensitive adhesive composition) by adjusting the coating solid content to about 30% by weight.

Production of adhesive polarizer

The prepared coating solution was coated on a release-treated surface of poly (ethylene terephthalate) (MRF-38, manufactured by Mitsubishi) having a thickness of 38 탆 and subjected to release treatment so that the thickness after drying was about 23 탆, For about 3 minutes. After drying, a WV liquid crystal layer of a polarizing plate (TAC / PVA / TAC laminated structure: TAC = triacetyl cellulose, PVA = polyvinyl alcohol polarizing film) coated with a WV (Wide View) liquid crystal layer on one side was laminated on the above- The formed coating layer was laminated to prepare a pressure-sensitive polarizer.

Example  1 to 3 and Comparative Example  1 to 3

A pressure-sensitive adhesive composition (coating solution) and a pressure-sensitive polarizing plate were prepared in the same manner as in Example 1, except that components and ratios were controlled as shown in Table 2 below.

Example Comparative Example One 2 3 One 2 3 acryl
polymer Kinds A1 A2 A3 B1 B2 B3 content 100 100 100 100 100 100 Cross-linking agent  content 0.07 0.2 0.4 0.2 0.07 0.07 DBTDL  content 0.1 0.1 0.1 0.1 0.1 0.1 SCA  content 0.2 0.2 0.2 0.2 0.2 0.2 Antistatic agent content 1.5 1.5 1.5 1.5 1.5 1.5 Content Unit: Weight portion
Cross-linking agent : Coronate  L, Japan NPU My
DBTDL : Dibutyltin dilaurate
SCA : Beta - Cyano acetyl group  Branch Silane Coupling agent ( M812 , LG Chemical)
Antistatic agent: LiTFSi : Lithium trifluorosulfonylimide

The results of the physical properties evaluation of each of the above Examples and Comparative Examples are shown in Table 3 below.

Example Comparative Example One 2 3 One 2 3 Surface resistance (initial) (× 10 ¹¹  Ω / □) One One One One One One Surface resistance (heat resistance, 7 days) (× 10 ¹¹  Ω / □) One One One 10 10 10 Surface resistance Wet heat , 7 days) (× 10 ¹¹ Ω / □) One One One over over over Heat resistance durability A A A C C C Wet heat  durability A A A C C B Over : 10 ¹⁴  Ω / □ or more

Claims (16)

A first block having a glass transition temperature of 50 DEG C or higher and a second block having a glass transition temperature of -10 DEG C or lower and containing a hydroxyl group; And an antistatic agent. The pressure-sensitive adhesive composition according to claim 1, wherein the block copolymer comprises 5 parts by weight to 50 parts by weight of the first block and 50 parts by weight to 95 parts by weight of the second block. The pressure-sensitive adhesive composition of claim 1, wherein the first block comprises polymerized units derived from alkyl methacrylate. The pressure-sensitive adhesive composition according to claim 1, wherein the second block comprises polymerized units derived from 60 to 99 parts by weight of an alkyl acrylate and 1 to 40 parts by weight of a copolymerizable monomer having a hydroxyl group. The pressure-sensitive adhesive composition according to claim 1, wherein the first block has a number-average molecular weight of 2,500 to 150,000. The pressure-sensitive adhesive composition according to claim 1, wherein the block copolymer has a number average molecular weight of 50,000 to 300,000. The pressure-sensitive adhesive composition according to claim 1, wherein the block copolymer has a molecular weight distribution of 1.0 to 2.5. The pressure-sensitive adhesive composition according to claim 1, wherein the block copolymer is a diblock copolymer having a first block and a second block. The pressure-sensitive adhesive composition according to claim 1, further comprising a polyfunctional crosslinking agent. The pressure-sensitive adhesive composition according to claim 9, wherein the crosslinking agent is contained in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the block copolymer. The pressure-sensitive adhesive composition according to claim 1, wherein the antistatic agent is an organic salt or a metal salt. The pressure-sensitive adhesive composition according to claim 1, wherein the antistatic agent is contained in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the block copolymer. A protective substrate layer; And a pressure-sensitive adhesive layer which is present on one side or both sides of the protective substrate layer and comprises the pressure-sensitive adhesive composition according to claim 1. Optical film; And a pressure-sensitive adhesive layer which is present on one or both sides of the optical film and comprises the pressure-sensitive adhesive composition of claim 1. A polarizer; And a pressure-sensitive adhesive layer which is present on one side or both sides of the polarizer and comprises the pressure-sensitive adhesive composition according to claim 1. A display device comprising the optical laminate of claim 14 or the polarizer of claim 15.