KR20190017448A - Crosslinkable composition - Google Patents

Abstract

The present application relates to: a crosslinkable composition; a protective film; an optical laminate; a polarizing plate; and a display unit. The present application provides the crosslinkable composition which has an excellent endurance reliability and light-leakage restraint. The crosslinkable composition of the present application can be used for optical films such as the protective film, the optical laminate, the polarizing plate and the like.

Description

CROSSLINKABLE COMPOSITION [0002]

The present invention relates to a crosslinkable composition, a protective film, an optical laminate, a polarizing plate and a display device.

Description of the Related Art [0002] A liquid crystal display device (hereinafter referred to as " LCD device ") typically includes a liquid crystal panel containing liquid crystal components injected between two transparent substrates and an optical film. Examples of the optical film include a polarizing film, a retardation film, and a brightness enhancement film. A pressure-sensitive adhesive for an optical film may be used to laminate the optical films or adhere the optical films to an adherend such as a liquid crystal panel. As general adhesive, acrylic polymer, rubber, urethane resin, silicone resin or ethylene vinyl acetate (EVA) resin can be used. The optical film is required to have transparency. In particular, as the pressure sensitive adhesive for a polarizing plate, a pressure sensitive adhesive containing an acrylic copolymer having excellent transparency and good resistance to oxidation and yellowing is generally used.

The main physical properties required for the crosslinkable composition for an optical film are cohesive force, adhesive force, reworkability, low light leakage property and stress relaxation property. In Patent Documents 1 to 3, a crosslinkable composition for achieving the above properties has been proposed.

Patent Document 1: Korean Patent No. 1023839 Patent Document 2: Korean Patent No. 1171976 Patent Document 3: Korean Patent No. 1171977

The present application provides a crosslinkable composition, a protective film, an optical laminate, a polarizing plate and a display device.

The present application relates to a crosslinkable composition. Exemplary crosslinkable compositions may include block copolymers. As used herein, the term " block copolymer " refers to a copolymer comprising different blocks of different polymerized monomers.

The crosslinkable composition of the present application may include a first block and a second block, and the first block may include a triblock copolymer bonded at both ends of the second block. In this application, the fact that the first block is coupled to both ends of the second block means that the first block is coupled to both ends of the second block through a chemical bond such as a covalent bond.

The triblock copolymer may include a first block having a glass transition temperature of 50 ° C or higher. In the present specification, the "glass transition temperature of a given block" of the block copolymer may mean the glass transition temperature calculated from the homopolymer of each of the monomers contained in the block, according to the following general formula (1).

[Formula 1]

1 / Tg =? Wn / Tn

In the above equation, Wn is the weight fraction of the monomer polymerized in each block of the block copolymer, and Tn is the glass transition temperature in the case where the monomer polymerized in the weight fraction of Wn in each block forms a homopolymer . That is, in the above formula, the numerical value (Wn / Tn) obtained by dividing the weight fraction of the polymerized monomer in a block on the right side by the glass transition temperature when the monomer is formed into a homopolymer is calculated for each monomer, .

The first block having a relatively high glass transition temperature can form a hard segment having a relatively rigid physical property in the block copolymer. The first block may be present in the form of glass at room temperature and may play a role of imparting cohesive force to the tackifier containing the triblock copolymer.

In one example, the glass transition temperature of the first block may be at least 60 ° C, at least 65 ° C, or at least 70 ° C. The upper limit of the glass transition temperature of the first block is not particularly limited and may be, for example, about 150 캜, 130 캜 or 110 캜.

The kind and content of the monomer forming the first block of the triblock copolymer are not particularly limited as long as the above-mentioned glass transition temperature can be ensured.

In one example, the first block may comprise a methacrylic acid ester monomer unit. In the present specification, when a monomer is included in a block, it may mean that the monomer undergoes a polymerization reaction to form a skeleton of the polymer or block or polymer, for example, a main chain or a side chain. As the methacrylic acid ester monomer, for example, alkyl methacrylate can be used. An alkyl methacrylate 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 can be used in consideration of control of cohesion, glass transition temperature and tackiness have. The alkyl group may be linear, branched or cyclic. Examples of such monomers include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, sec-butyl methacrylate, pentyl Acrylate, methacrylate, 2-ethylhexyl methacrylate, 2-ethylbutyl methacrylate, n-octyl methacrylate, isobornyl methacrylate, isooctyl methacrylate, isononyl methacrylate, And the like, and one or more of the above can be selected so as to secure the glass transition temperature. As the monomer forming the first block in consideration of the ease of controlling the glass transition temperature and the like, methacrylic acid ester monomers such as alkyl methacrylate and the like in the above monomers, for example, monomers having 1 to 20 carbon atoms, 1 to 16 carbon atoms, Alkyl methacrylates having 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms can be used.

The triblock copolymer may include a second block having a glass transition temperature of -10 캜 or lower. The second block having a relatively low glass transition temperature can form a soft segment having relatively soft properties in the block copolymer. The second block may have a molecular flow property at room temperature and may provide stress relievability to the pressure sensitive adhesive containing the block copolymer.

At least the copolymer comprising the two types of blocks can form a fine phase separation structure in the pressure sensitive adhesive. Such a block copolymer exhibits an appropriate cohesive force and stress relaxation property in accordance with a change in temperature, and can form a crosslinkable composition which maintains excellent physical properties required for an optical film such as durability reliability, light-shielding property and reworkability.

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

The kind and content of the monomer forming the second block of the triblock copolymer are not particularly limited as long as the above-mentioned glass transition temperature can be ensured.

In one example, the second block may comprise acrylic acid ester monomer units. As the acrylic acid ester monomer, monomers capable of securing a glass transition temperature in the above-described range through copolymerization with the copolymerizable monomers among the monomers that may be contained in the second block can be selected and used have. The kind of the acrylic acid ester monomer forming the second block is, for example, one having 20 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, Alkyl acrylates having 1 to 4 alkyl groups can be used, but the present invention is not limited thereto.

The triblock copolymer may be a crosslinkable copolymer having a crosslinkable functional group. As the crosslinkable functional group, a hydroxyl group, a carboxyl group, an isocyanate group or a glycidyl group can be exemplified. In one example, the crosslinkable functional group of the block copolymer may be a hydroxy group.

The crosslinkable functional group contained in the triblock copolymer can be included in the second block, which is a block having a relatively low glass transition temperature in one example, and is preferably included in the second block only have. When a crosslinkable functional group is included in the second block, a crosslinkable composition exhibiting an appropriate cohesive force and stress relaxation property in accordance with a change in temperature and having excellent physical properties such as durability, light-shielding properties and reworkability can be formed.

As a method for incorporating a crosslinkable functional group into the block copolymer, in one example, a copolymerizable monomer containing a crosslinkable functional group may be used. Examples of the copolymerizable monomer having a crosslinkable functional group include a monomer having a moiety copolymerizable with another monomer contained in a block copolymer such as the acrylic acid ester monomer and having the above-described crosslinkable functional group .

In the production of pressure-sensitive adhesives, a variety of copolymerizable monomers having the above-mentioned crosslinkable functional groups are known, and these monomers can all be used in the polymerization of the block copolymer of the present application. As the copolymerizable monomer having a crosslinkable functional group of the present application, for example, a copolymerizable monomer having a hydroxyl group can be used. Examples of the copolymerizable monomer having a hydroxy group include 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 6-hydroxyhexyl acrylate or 8- Hydroxyalkyl acrylate such as octyl acrylate, or hydroxyalkylene glycol acrylate such as 2-hydroxyethyleneglycol acrylate or 2-hydroxypropyleneglycol acrylate, but the present invention is not limited thereto. The copolymerizable monomer having a hydroxy group may preferably constitute a polymerization unit of the second block. In this case, considering the reactivity with other monomers forming the second block and the ease of controlling the glass transition temperature, Acrylate, hydroxyalkylene glycol acrylate, and the like, but the present invention is not limited thereto.

In one example, the second block may comprise 60 parts by weight to 99.9 parts by weight of (meth) acrylic acid ester monomer units and 0.1 to 40 parts by weight of copolymerizable monomer units having a crosslinkable functional group. In another example, the second block may contain 80 to 99.9 parts by weight of (meth) acrylic acid ester monomer units and 0.1 to 20 parts by weight of copolymerizable monomer units having a crosslinkable functional group. In another example, the second block may contain 90 to 99.9 parts by weight of (meth) acrylic acid ester monomer units and 0.1 to 10 parts by weight of copolymerizable monomer units having a crosslinkable functional group. The term weight in the present application may mean a relative proportion of the weight of each component.

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.

In one example, the second block in the triblock copolymer may have a Number Average Molecular Weight (Mn) of, for example, from 2,500 to 150,000. The number average molecular weight of the second block may mean, for example, the number average molecular weight of the polymer produced by polymerizing only the monomer forming the second 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 lower limit of the number average molecular weight of the second block may be, for example, at least 2,500, at least 3,000, at least 4,000, at least 5,000, at least 6,000, at least 7,000, at least 8,000, at least 10,000, at least 30,000, The upper limit of the number average molecular weight of the second block may be, for example, 150,000 or less, 140,000 or less, 120,000 or less, 100,000 or less, or 80,000 or less.

The molecular weight distribution (PDI, Mw / Mn) of the second block may be 1.0 to 3.0, for example. The upper limit of the molecular weight distribution of the second block may be, for example, 2.6 or less or 2.2 or less. The lower limit of the molecular weight distribution of the second block may be, for example, 1.4 or more or 1.8 or more. By controlling the molecular weight characteristics of the second block in the above range, the pressure-sensitive adhesive can have excellent endurance reliability, cohesion and stress relaxation property.

The triblock copolymer may comprise, for example, from 50 wt% to 95 wt% of the second block. The lower limit of the content of the second block may be, for example, 55 wt% or more or 60 wt% or more. The upper limit of the content of the second block may be, for example, 93% by weight or less or 90% by weight or less. The triblock copolymer may include 5 to 100 parts by weight of the first block relative to 100 parts by weight of the second block. The lower limit of the content of the first block may be, for example, 15 parts by weight or more and 20 parts by weight or more based on 100 parts by weight of the second block. The upper limit of the content of the first block may be, for example, 80 parts by weight or less, 70 parts by weight or 60 parts by weight or less based on 100 parts by weight of the second block. By controlling the ratio of the weight between the first block and the second block as described above, it is possible to provide a crosslinkable composition having excellent physical properties.

The number average molecular weight of the triblock copolymer may be, for example, from 5,000 to 200,000. The upper limit of the number average molecular weight of the triblock copolymer may be, for example, 160,000 or less, 120,000 or less, or 90,000 or less. The lower limit of the number average molecular weight of the triblock copolymer may be, for example, 25,000 or more, 35,000 or more, or 45,000 or more. The molecular weight distribution (Poly Dispersity Index, PDI, Mw / Mn) of the triblock copolymer may be, for example, 1.0 to 3.0. The upper limit of the molecular weight distribution of the triblock copolymer may be, for example, 2.8 or less or 2.6 or less. The lower limit of the molecular weight distribution of the triblock copolymer may be, for example, 1.5 or more or 2.0 or more. By controlling the molecular weight characteristics of the triblock copolymer in the above range, the tackifier containing the triblock copolymer can have excellent endurance reliability, cohesive force and stress relaxation property.

The crosslinkable composition of the present application may comprise a diblock copolymer. The diblock copolymer may include a third block and a fourth block.

The third block may have a glass transition temperature of 50 ° C or higher. The third block having a relatively high glass transition temperature can form a hard segment having a relatively rigid physical property in the block copolymer. The third block may be present in the form of glass at room temperature and may provide a cohesive force to the pressure sensitive adhesive containing the diblock copolymer.

In one example, the glass transition temperature of the third block may be at least 60 ° C, at least 65 ° C, or at least 70 ° C. The upper limit of the glass transition temperature of the third block is not particularly limited and may be, for example, about 150 캜, 130 캜 or 110 캜.

The type and content of the monomers forming the third block of the diblock copolymer are not particularly limited as long as they can secure the above glass transition temperature.

In one example, the third block may comprise a methacrylic acid ester monomer unit. As the methacrylic acid ester monomer, for example, alkyl methacrylate can be used. An alkyl methacrylate 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 can be used in consideration of control of cohesion, glass transition temperature and tackiness have. The alkyl group may be linear, branched or cyclic. Examples of such monomers include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, sec-butyl methacrylate, pentyl Acrylate, methacrylate, 2-ethylhexyl methacrylate, 2-ethylbutyl methacrylate, n-octyl methacrylate, isobornyl methacrylate, isooctyl methacrylate, isononyl methacrylate, And the like, and one or more of the above can be selected so as to secure the glass transition temperature. As the monomer forming the third block in consideration of the ease of controlling the glass transition temperature and the like, methacrylic acid ester monomers such as alkyl methacrylate and the like in the above monomers, for example, monomers having 1 to 20 carbon atoms, 1 to 16 carbon atoms, Alkyl methacrylates having 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms can be used.

In one example, the third block in the diblock copolymer may have a Number Average Molecular Weight (Mn) of, for example, from 2,500 to 150,000. The number average molecular weight of the third block may mean, for example, the number average molecular weight of the polymer produced by polymerizing only the monomer forming the third 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 lower limit of the number average molecular weight of the third block may be, for example, at least 2,500, at least 3,000, at least 4,000, at least 5,000, at least 6,000, at least 7,000, at least 8,000, at least 15,000, at least 35,000, The upper limit of the number average molecular weight of the second block may be, for example, 150,000 or less, 140,000 or less, 120,000 or less, 100,000 or less, or 85,000 or less.

The molecular weight distribution (Poly Dispersity Index, PDI, Mw / Mn) of the third block may be, for example, 0.5 to 2.0. The upper limit of the molecular weight distribution of the third block may be, for example, 1.8 or less or 1.6 or less. The lower limit of the molecular weight distribution of the third block may be, for example, 0.8 or more or 1.1 or more. By controlling the molecular weight characteristics of the second block in the above range, the pressure-sensitive adhesive can have excellent endurance reliability, cohesion and stress relaxation property.

The diblock copolymer may include a fourth block having a glass transition temperature of -10 캜 or lower. The fourth block having a relatively low glass transition temperature can form a soft segment having relatively soft properties in the block copolymer. The fourth block may have a molecular flow property at room temperature and may play a role of imparting stress relaxation property to the pressure sensitive adhesive containing the block copolymer.

In one example, the glass transition temperature of the fourth block may be -20 占 폚 or lower, -30 占 폚 or lower, -35 占 폚 or lower, or -40 占 폚 or lower. The lower limit of the glass transition temperature of the fourth block is not particularly limited and may be, for example, about -80 캜, -70 캜, -60 캜 or -55 캜.

The kind and content of the monomer forming the fourth block of the diblock copolymer are not particularly limited as long as the above-mentioned glass transition temperature can be ensured.

In one example, the fourth block may comprise acrylic acid ester monomer units. As the acrylic acid ester monomer, monomers capable of securing a glass transition temperature in the above-described range through copolymerization with the copolymerizable monomers among the monomers that may be contained in the fourth block can be selected and used have. The kind of the acrylic acid ester monomer forming the fourth block is, for example, 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or a carbon number Alkyl acrylates having 1 to 4 alkyl groups can be used, but the present invention is not limited thereto.

The triblock copolymer may be a crosslinkable copolymer having a crosslinkable functional group. As the crosslinkable functional group, a hydroxyl group, a carboxyl group, an isocyanate group or a glycidyl group can be exemplified. In one example, the crosslinkable functional group of the block copolymer may be a hydroxy group.

In one example, the crosslinkable functional group contained in the diblock copolymer may be included in the fourth block, which is a relatively low glass transition temperature, and is preferably included in the fourth block only, not included in the third block have. When the crosslinkable functional group is included in the fourth block, it is possible to form a crosslinkable composition which exhibits appropriate cohesive force and stress relaxation property in accordance with a change in temperature and maintains excellent physical properties such as endurance reliability, light-shielding property and reworkability.

As a method for incorporating a crosslinkable functional group into the block copolymer, in one example, a copolymerizable monomer containing a crosslinkable functional group may be used. Examples of the copolymerizable monomer having a crosslinkable functional group include a monomer having a moiety copolymerizable with another monomer contained in a block copolymer such as the acrylic acid ester monomer and having the above-described crosslinkable functional group .

In the production of pressure-sensitive adhesives, a variety of copolymerizable monomers having the above-mentioned crosslinkable functional groups are known, and these monomers can all be used in the polymerization of the block copolymer of the present application. As the copolymerizable monomer having a crosslinkable functional group of the present application, for example, a copolymerizable monomer having a hydroxyl group can be used. Examples of the copolymerizable monomer having a hydroxy group include 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 6-hydroxyhexyl acrylate or 8- Hydroxyalkyl acrylate such as octyl acrylate, or hydroxyalkylene glycol acrylate such as 2-hydroxyethyleneglycol acrylate or 2-hydroxypropyleneglycol acrylate, but the present invention is not limited thereto. The copolymerizable monomer having a hydroxy group may preferably constitute a polymerization unit of the second block. In this case, considering the reactivity with other monomers forming the second block and the ease of controlling the glass transition temperature, Acrylate, hydroxyalkylene glycol acrylate, and the like, but the present invention is not limited thereto.

In one example, the fourth block may comprise 60 to 99.9 parts by weight of (meth) acrylic acid ester monomer units and 0.1 to 40 parts by weight of copolymerizable monomer units having a crosslinkable functional group. In another example, the fourth block may contain 80 to 99.9 parts by weight of (meth) acrylic acid ester monomer units and 0.1 to 20 parts by weight of copolymerizable monomer units having a crosslinkable functional group. In another example, the fourth block may contain 90 to 99.9 parts by weight of (meth) acrylic acid ester monomer units and 0.1 to 10 parts by weight of copolymerizable monomer units having a crosslinkable functional group.

The third block and / or the fourth 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 a polymerized unit 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 diblock copolymer may comprise, for example, from 50% by weight to 95% by weight of the fourth block. The lower limit of the content of the fourth block may be, for example, 55 wt% or more or 60 wt% or more. The upper limit of the content of the fourth block may be, for example, 95 wt% or less, 93 wt% or less, or 90 wt% or less. The diblock copolymer may include, for example, 5 to 100 parts by weight of a third block, based on 100 parts by weight of the fourth block. The lower limit of the content of the third block may be, for example, 7 parts by weight or more or 10 parts by weight or more. The upper limit of the content of the third block may be, for example, 85 parts by weight or less, 80 parts by weight or less, or 75 parts by weight or less. The ratio of the weight between the third block and the fourth block is adjusted as described above to provide a crosslinkable composition having excellent physical properties.

The number average molecular weight of the diblock copolymer may be, for example, 100,000 to 600,000. The upper limit of the number average molecular weight of the diblock copolymer may be, for example, 530,000 or less, 460,000 or less, or 400,000 or less. The lower limit of the number average molecular weight of the diblock copolymer may be, for example, 140,000 or more, 170,000 or more, or 200,000 or more. The molecular weight distribution (PDI, Mw / Mn) of the diblock copolymer may be, for example, 1.0 to 3.0. The upper limit of the molecular weight distribution of the diblock copolymer may be, for example, 2.9 or less or 2.8 or less. The lower limit of the molecular weight distribution of the diblock copolymer may be, for example, 1.5 or more or 2.0 or more. By controlling the molecular weight characteristics of the diblock copolymer in the above range, the pressure sensitive adhesive containing the diblock copolymer can have excellent endurance reliability, cohesive force and stress relaxation property.

The crosslinkable composition of the present application may contain, for example, a triblock copolymer in a proportion of 1 to 40% by weight. The lower limit of the content of the triblock copolymer may be, for example, 3 wt% or more or 5 wt% or more. The upper limit of the content of the triblock copolymer may be, for example, 35 wt% or less or 30 wt% or less. The crosslinkable composition of the present application may contain, for example, a diblock copolymer in a proportion of 150 to 9900 parts by weight based on 100 parts by weight of the triblock copolymer. The lower limit of the content of the diblock copolymer may be, for example, 180 parts by weight or more or 230 parts by weight or more based on 100 parts by weight of the triblock copolymer. The upper limit of the content of the diblock copolymer may be, for example, 9700 parts by weight or less, 9500 parts by weight or 9000 parts by weight or less based on 100 parts by weight of the triblock copolymer. The ratio of the weight of the triblock copolymer and the diblock copolymer is adjusted as described above to provide a crosslinkable composition having excellent physical properties.

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), which conducts 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 crosslinkable composition may include a crosslinking agent capable of crosslinking the block copolymer. The crosslinking agent may react with the crosslinking point of the block copolymer, that is, the crosslinking functional group described above to realize a crosslinked structure. As the crosslinking agent, a crosslinking agent having at least two functional groups capable of reacting with the crosslinkable functional group contained in the block copolymer may be used.

A variety of crosslinking agents as described above are known in the art of the production of pressure-sensitive adhesives, and these crosslinking agents may all be used in the preparation of the crosslinkable compositions of the present application. In one example, one or more isocyanate crosslinking agents may be used as the crosslinking agent of the present application.

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 crosslinking agent may be included in the crosslinkable composition in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the total amount of the triblock copolymer and the diblock copolymer. The lower limit of the content of the crosslinking agent may be, for example, 0.02 parts by weight or 0.03 parts by weight. The upper limit of the content of the crosslinking agent may be, for example, 5 parts by weight or less or 1.5 parts by weight or less. By controlling the content of the cross-linking agent within the above-mentioned range, the cohesive force, adhesive strength and durability of the pressure-sensitive adhesive can be excellently controlled.

The crosslinkable 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 adhesion 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 ₆ ) _n Si (R ₇ ) _(4-n)

 (3)

(R ₈ ) _n Si (R ₆ ) _(4-n)

In the general formula (2) or (3), R ₆ is a beta-cyanoacetyl group or a beta-cyanoacetylalkyl group, R ₈ is an acetoacetyl group or an acetoacetylalkyl group, R ₇ is an alkoxy group, Number.

 In 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 crosslinkable 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 total amount of the triblock copolymer and the diblock copolymer, The physical properties can be effectively imparted to the pressure-sensitive adhesive.

The crosslinkable composition may further comprise a tackifier as necessary. 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 contained in the crosslinkable composition in an amount of 100 parts by weight or less based on 100 parts by weight of the block copolymer.

The crosslinkable composition may contain, if necessary, a known additive such as an antistatic agent, a coordinating compound capable of forming a coordination bond with the antistatic agent, an epoxy resin, a curing agent, a UV stabilizer, an antioxidant, a colorant, A filler, a defoaming agent, a surfactant, and a plasticizer.

The crosslinkable composition may be a crosslinkable composition for a protective film. The protective film can be used, for example, for protecting the surface of various optical films.

The crosslinkable composition may be a crosslinkable composition for an optical film. The crosslinkable composition for an optical film can be obtained by, for example, laminating an optical film such as a polarizing film, a retardation film, an anti-glare film, a wide viewing angle compensating film or a luminance improving film, Can be used for adhering to the same adherend. In one example, the crosslinkable composition may be a crosslinkable composition for use in adhering a polarizing film to a liquid crystal panel as a crosslinkable composition for a polarizing plate.

In one example, the present application is directed to a pressure-sensitive adhesive optical laminate. Exemplary optical stacks include optical films; And an adhesive layer present on one side or both sides of the optical film. The pressure-sensitive adhesive layer may be, for example, a pressure-sensitive adhesive layer for adhering the optical film to a liquid crystal panel or other optical film of an LCD device. The pressure-sensitive adhesive layer may include the cross-linkable composition of the present invention described above. The crosslinkable composition may be included in the pressure-sensitive adhesive layer in a crosslinked state. Examples of the optical film include a polarizing plate, a polarizer, a retardation film, a brightness enhancement film, or a laminate in which two or more of the above are laminated. 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 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 or both sides of the protective film. In one example, the pressure-sensitive adhesive layer may be formed on the opposite side of the polarizer 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 polarizing plate or the optical film in the present application is not particularly limited. For example, a method of directly coating the crosslinkable composition and curing it to realize a crosslinked structure, A method of coating and curing the crosslinkable composition on the treated surface to form a crosslinked structure and then transferring the crosslinked composition may be used.

The method of coating the crosslinkable composition is not particularly limited, and for example, a method of applying the crosslinkable composition by a common means such as a bar coater may be used.

The cross-linking agent contained in the cross-linking composition during the coating process is preferably controlled in such a manner that the cross-linking reaction of the functional group does not proceed from the viewpoint of performing a uniform coating process. Thus, To improve the cohesive force of the pressure-sensitive adhesive, and to improve the adhesive property, cuttability, and the like.

The coating process is also preferably performed after sufficiently removing the bubble-inducing component such as volatile components or reaction residues in the crosslinkable composition, so that 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 to form a scattering body therein.

The method of curing the crosslinkable composition to form a crosslinked structure is also not particularly limited. For example, the coating layer may be maintained at a proper temperature such that a crosslinking reaction between the block copolymer contained in the coating layer and the multi- Method or 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.

The liquid crystal panel may include, for example, a first substrate sequentially formed, a pixel electrode, a first alignment film, a liquid crystal layer, a second alignment film, a common electrode, and a second substrate. In one example, the first substrate and the second substrate may be glass substrates. In this case, the polarizer or the optical laminate may be attached to the glass substrate via the above-described pressure-sensitive adhesive layer.

The apparatus may further include a light source on the opposite side of the viewing side of the liquid crystal panel. In the first substrate on the light source side, for example, an active driving circuit including TFT (Thin Film Transistor), wiring and the like may be formed as a driving element electrically connected to the transparent pixel electrode. The pixel electrode includes, for example, ITO (Indium Tin Oxide) or the like and can function as an electrode for each pixel. In addition, the first or second alignment film may include, for example, a material such as polyimide, but is not limited thereto.

Examples of the liquid crystal panel in the apparatus 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 a liquid crystal display device are not particularly limited, and configurations known in this field can be employed without limitation.

In the present application, a crosslinkable composition having excellent physical properties such as endurance reliability and flexural strength can be provided. The crosslinkable composition of the present application can be used, for example, for an optical film such as a protective film, a polarizing plate and the like.

1 is a view for explaining a method of measuring a flexural restraining force of a pressure-sensitive adhesive composition.

The crosslinkable composition will be described in detail in the following examples and comparative examples, but the range of the crosslinkable 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 Chromatograph), and the GPC measurement conditions 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. Evaluation of durability

The polarizing plates prepared in Examples and Comparative Examples were cut to have a width of 180 mm and a length of 320 mm, and they were attached to a 19-inch commercial liquid crystal panel. Thereafter, the panel with the polarizing plate is stored for about 20 minutes in an autoclave (50 DEG C, 5 atm) to prepare a sample. The durability against moisture and heat 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: After 500 hours of operation, the occurrence of bubbles and peeling was also 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

3. Bending Measurement

Prepare STN sodalime glass for bending (width 4cm, length 41cm, thickness 0.4t). A polarizing plate (coated product) with a pressure-sensitive adhesive is prepared in the MD direction in a length of 3.5 x 40 cm &lt; ² &gt; and attached to the glass. As shown in Fig. 1, fix one side of the bending sample to the device that can fix the sample in the chamber and measure the distance from the reference point. After measuring the initial value, measure the distance from the reference point after holding for 72 hours under 60 ℃ heat-resistant condition. Prepare three samples for the same prescription and calculate the average value. When the fin distance is 35 mm or more, the degree of light leakage due to warping is considered to be considerable.

4. Estimation of glass transition temperature

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

<Formula>

1 / Tg =? Wn / Tn

In the above formula, 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 corresponding monomer forms a homopolymer. That is, in the above formula, the value obtained by dividing the weight fraction of the used monomer by the glass transition temperature (Wn / Tn) obtained when the monomer is formed into the homopolymer is calculated for each monomer on the right side to be.

5. Evaluation of thermal shock characteristics

In addition, the thermal shock property is evaluated for the samples whose durability has been evaluated. The evaluation of thermal shock characteristics is performed by a thermal shock tester of DIMOS TECH. The evaluation is carried out by repeatedly moving the sample between -40 ° C and 90 ° C and leaving the sample in the low temperature and high temperature sections for 30 minutes each. One cycle of passing through the low temperature and high temperature sections is taken as one criterion, and the thermal shock characteristic is evaluated according to the following criteria.

<Evaluation Criteria of Thermal Shock Characteristics>

A: When bubbles and peeling phenomenon are not observed in over 200 cycles

B: When bubbles and / or peeling phenomenon is observed at least 150 cycles

C: A large amount of bubbles and / or peeling phenomenon is observed in over 100 cycles

Production Example 1. Preparation of triblock copolymer (A1)

0.2 g of EBiB (ethyl 2-bromoisobutyrate) and 120.8 g of butyl acrylate (n-BA, n-butylacrylate), 3.7 g of 4-hydroxybutylacrylate (4-HBA) and 30 g of ethylacetate Was sealed in the reactor and nitrogen purging and stirring were performed at about 25 ° C for about 30 minutes and then dissolved oxygen was removed through bubbling. Thereafter, 0.005 g of CuBr ₂ , 0.013 g of tris (2-pyridylmethyl) amine, and 0.1 g of V-65 (2,2'-azobis (2,4-dimethyl valeronitrile) And the reaction was started by immersing in a reaction tank at about 67 ° C (polymerization of the second block). A mixture of 35.4 g of methyl methacrylate (MMA, methylmethacrylate) previously bubbled with nitrogen and 40 g of ethyl acetate (EAc, ethylacetate) was added in the presence of nitrogen at a time when the monomer conversion was about 90%. Thereafter, 0.004 g of CuBr ₂ , 0.01 g of TPMA and 0.06 g of V-65 were added to the reactor, and a chain extension reaction was carried out (the first block was polymerized at both ends of the second block). When the conversion rate reaches 80% or more, the reaction mixture is exposed to oxygen, diluted with an appropriate solvent to terminate the reaction to obtain a diblock copolymer having a number average molecular weight (Mn) of 72,000 and a molecular weight distribution (Mw / Mn) . In the above, the weight ratio of the first block: the second block: the first block is about 15:70:15.

Production Example 2 Preparation of diblock copolymer (A2)

0.032 g of EBiB, 11.4 g of methyl methacrylate (MMA) and 2.9 g of butyl methacrylate (BMA) were mixed in 6.1 g of ethyl acetate (EAc). The reactor containing the mixture was sealed, purged with nitrogen at about 25 ° C for about 30 minutes and stirred, and dissolved oxygen was removed through bubbling. Then 0.002 g of CuBr ₂ , 0.006 g of TPMA and 0.003 g of V-65 were added to the oxygen-depleted mixture and the reaction was initiated by dipping in a reactor at about 67 ° C (polymerization of the third block). 111.4 g of butyl acrylate (n-BA) previously bubbled with nitrogen, 1.1 g of hydroxybutyl acrylate (4-HBA) and ethyl acetate (EAc) were added at the time when the conversion of methyl methacrylate was about 70% Was added in the presence of nitrogen. Then, 0.004 g of CuBr ₂ , 0.01 g of TPMA and 0.01 g of V-65 were added to the reactor, and a chain extension reaction was carried out (polymerization of the fourth block). When the conversion of the monomer (n-BA) reaches 80% or more, the reaction mixture is exposed to oxygen and diluted with a suitable solvent to complete the reaction to give a number average molecular weight (Mn) of 320,000 and a molecular weight distribution (Mw / Mn) Was 2.63. In the above, the weight ratio of the third block to the fourth block is about 10:90.

Production Example 3. Preparation of diblock copolymer (B1)

A block copolymer was prepared in the same manner as in Preparation Example 2, except that the raw materials used in the polymerization of the first block and the second block were controlled in the ratio shown in Table 1 below.

Block copolymer A1 A2 B1 The first block
(Third block) MMA ratio (pt) 100 60 60 BMA ratio (pt) 0 40 40 Tg (° C) 110 70 70 Mn (x 10000) - 6.7 1.0 PDI - 1.38 1.36 The second block
(Fourth block) n-BA ratio (pt) 99 99 99 4-HBA ratio (pt) One One One Tg (° C) -45.0 -45.0 -45.0 Block copolymer First block: second block: first block
(Third block: fourth block) Weight ratio 15:70:15 10:90 10:90 Mn (x 10000) 7.2 32.0 9.1 PDI 2.52 2.63 2.4 Monomer Ratio Units: parts by weight (pt)
n-BA: n-butyl acrylate (homopolymer Tg: about -45 ° C)
4-HBA: 4-hydroxybutyl acrylate (homopolymer Tg: about -80 ° C)
MMA: methyl methacrylate (homopolymer Tg: approx. 110 ° C)
BMA: butyl methacrylate (homopolymer Tg: about 27 ° C)
Tg: glass transition temperature
Mn: number average molecular weight
PDI: molecular weight distribution

Manufacturing example  4. Preparation of random copolymer (B2)

To a 1 L reactor equipped with a cooling device for regulating the temperature of the reflux of nitrogen gas was added a monomer mixture composed of 99 parts by weight of n-butyl acrylate (n-BA) and 1.0 part by weight of 4-hydroxybutyl acrylate (4-HBA) Lt; / RTI &gt; Then, 150 parts by weight of ethylacetate (EAc) was added as a solvent. To remove oxygen, nitrogen gas was purged for 60 minutes, the temperature was maintained at 60 ° C, and 0.03 part by weight of azobisisobutyronitrile (AIBN) as a reaction initiator was added thereto, followed by reaction for 8 hours To prepare a random copolymer (B2). The weight average molecular weight was 1.8 million, and the molecular weight distribution was 5.1.

Example  One.

Coating liquid ( Crosslinkability  Composition)

10 parts by weight of the triblock copolymer (A1), 0.1 part by weight of a crosslinking agent (Coronate L, Japan NPU), and 0.1 part by weight of a silane coupling agent having a beta-cyanoacetyl group were added to 90 parts by weight of the diblock copolymer (A2) (M812, manufactured by LG Chemical Co., Ltd.) were mixed, and ethyl acetate was mixed as a solvent to adjust the coating solid content to about 20% by weight, to prepare a coating solution (crosslinkable composition).

Production of adhesive polarizer

The prepared coating solution was coated on the mold-releasing surface of poly (ethylene terephthalate) (MRF-38, Mitsubishi) having a thickness of 38 탆, which had been subjected to a release treatment so as to have a thickness of about 23 탆 after drying, For about 3 minutes. After drying, a coating layer formed on the release PET was laminated on one side of a polarizing plate (COP / PVA / COP laminated structure, COP being a cyclopolyolefin and PVA being a polyvinyl alcohol-based polarizing film) to produce a pressure-sensitive polarizing plate.

Example  2 and Comparative Example  1 to 5

An 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 when preparing the crosslinkable composition (coating liquid).

The results of the physical properties evaluation of each of the above Examples and Comparative Examples are shown in Table 2 below.

Example Comparative Example One 2 One 2 3 4 5 Acrylic polymer A1 10 20 90 100 0 10 0 A2 90 80 10 0 100 0 0 B1 0 0 0 0 0 90 0 B2 0 0 0 0 0 0 100 Heat resistance durability A A C C B C C Wet heat resistance A A C C B C B Bending distance (mm) 32 34 38 40 35 30 55 Thermal Shock Characteristics A A C C C C C

When the triblock copolymer and the diblock copolymer were mixed at an appropriate weight ratio as in Example 1-2, the physical crosslinking points due to the triblock copolymer increased, resulting in excellent durability and excellent deflection characteristics due to appropriate stress relaxation Thereby obtaining a crosslinkable composition having a flexural distance of 35 mm or less. On the other hand, as in Comparative Examples 1 to 3, when the content of the triblock copolymer is too high or when the triblock or diblock copolymer is used alone, the durability or the flexural restraining property becomes poor. In the case of Comparative Example 4, the durability is inferior even if the number average molecular weight of the diblock copolymer is small even if the triblock copolymer is included.

Claims (24)

A triblock copolymer comprising 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 and the first block being bonded to both ends of the second block; And
Wherein the triblock copolymer is contained in a proportion of 150 to 9900 parts by weight based on 100 parts by weight of the triblock copolymer and has a number average molecular weight within a range of 100,000 to 600,000. The crosslinkable composition according to claim 1, which comprises a triblock copolymer in a proportion of 1 to 40% by weight. The crosslinkable composition according to claim 1, wherein the triblock copolymer comprises a crosslinkable functional group in the second block. The crosslinkable composition of claim 1, wherein the diblock copolymer comprises a third block having a glass transition temperature of 50 ° C or higher and a fourth block having a glass transition temperature of -10 ° C or lower. The crosslinkable composition according to claim 1, wherein the first block comprises a methacrylic acid ester monomer unit. The crosslinkable composition according to claim 1, wherein the second block comprises 60 to 99.9 parts by weight of an acrylate ester monomer unit and 0.1 to 40 parts by weight of a copolymerizable monomer unit having a crosslinkable functional group. The crosslinkable composition of claim 1, wherein the triblock copolymer comprises 5 to 100 parts by weight of the first block relative to 100 parts by weight of the second block. The crosslinkable composition of claim 1, wherein the second block has a number average molecular weight of from 2,500 to 150,000. The crosslinkable composition according to claim 1, wherein the second block has a molecular weight distribution (Mw / Mn) of 1.0 to 3.0. The crosslinkable composition according to claim 1, wherein the triblock copolymer has a number average molecular weight of from 5,000 to 200,000. The crosslinkable composition according to claim 1, wherein the triblock copolymer has a molecular weight distribution (Mw / Mn) of 1.0 to 3.0. The crosslinkable composition according to claim 1, wherein the third block comprises a methacrylic acid ester monomer unit. The crosslinkable composition according to claim 1, wherein the fourth block comprises 60 to 99.9 parts by weight of an acrylate ester monomer unit and 0.1 to 40 parts by weight of a copolymerizable monomer unit having a crosslinkable functional group. The crosslinkable composition of claim 1, wherein the diblock copolymer comprises 50% to 95% by weight of the fourth block. The crosslinkable composition of claim 1, wherein the diblock copolymer comprises 5 to 100 parts by weight of a third block relative to 100 parts by weight of the fourth block. The crosslinkable composition according to claim 1, wherein the third block has a number average molecular weight of 2,500 to 150,000. The crosslinkable composition according to claim 1, wherein the third block has a molecular weight distribution (Mw / Mn) of 0.5 to 2.0. The crosslinkable composition according to claim 1, wherein the diblock copolymer has a molecular weight distribution (Mw / Mn) of 1.0 to 3.0. The crosslinkable composition of claim 1, further comprising a crosslinking agent. The crosslinkable composition according to claim 19, 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 total amount of the diblock copolymer and the triblock copolymer. A protective substrate layer; And a pressure-sensitive adhesive layer formed on one side or both sides of the protective substrate layer, wherein the pressure-sensitive adhesive layer comprises the crosslinkable composition of claim 1. Optical film; And a pressure-sensitive adhesive layer formed on one surface or both surfaces of the optical film, wherein the pressure-sensitive adhesive layer comprises the crosslinkable composition of claim 1 in a crosslinked state. A polarizer including a polarizer; And an adhesive type polarizing plate formed on one or both surfaces of the polarizer, wherein the adhesive composition comprises the crosslinkable composition of claim 1 in a crosslinked state. A display device comprising the optical laminate of claim 22 or the adhesive polarizer of claim 24.

Images