KR101910147B1 - Crosslinkable composition - Google Patents

Abstract

This application is directed to crosslinkable compositions and uses thereof. In the present application, a chemical crosslinking and a physical crosslinking can be simultaneously performed to provide a crosslinkable composition capable of securing properties suitable for various uses including optical use, and the use of such a composition can be provided.

Description

CROSSLINKABLE COMPOSITION [0002]

The present application relates to a crosslinkable composition.

Crosslinkable compositions can be used in a variety of applications. For example, the pressure-sensitive adhesive composition or adhesive composition, which is one example of the crosslinkable composition, can be used in a display device such as a liquid crystal display (hereinafter, referred to as "LCD device") or the like, have.

The present application provides a crosslinkable composition.

This application is directed to a crosslinkable composition. The cross-linkable composition in the present application may mean a composition capable of causing a cross-linking reaction either of chemical cross-linking or physical cross-linking, for example, a composition capable of simultaneously causing the chemical and physical cross-linking, May refer to a composition comprising a component capable of implementing a crosslinked structure by physical means.

The crosslinkable composition may be, for example, a pressure-sensitive adhesive composition or an adhesive composition.

Exemplary crosslinkable compositions may include block copolymers. The composition may include the block copolymer as a main component. In the present application, the block copolymer is contained as a main component in that the weight ratio of the block copolymer in the composition is at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80% , 85% or more, 90% or more, or 95% or more. When the crosslinkable composition contains a solvent in the calculation of the weight ratio, the weight ratio may be a concentration of a block copolymer in a solid basis, that is, a solid content, or a ratio based on the other components excluding the solvent . As used herein, the term " block copolymer " may refer to a polymer in which two or more polymer blocks chemically different from each other are linked by a covalent bond through one end of the chain.

In one example, the block copolymer may comprise a first block and a second block having a lower glass transition temperature than the first block.

In one example, the glass transition temperature of the first block may be at least 30 < 0 > C. Further, the glass transition temperature of the second block may be 0 占 폚 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, or at least 70 ° C. The upper limit of the glass transition temperature of the first block is not particularly limited, but may be, for example, 250 占 폚, 200 占 폚, 150 占 폚, 140 占 폚, 130 占 폚, or 120 占 폚. In another example, the glass transition temperature of the second block may be -10 占 폚 or lower, -20 占 폚 or lower, -30 占 폚 or lower, -35 占 폚 or lower, -40 占 폚 or lower or -45 占 폚 or lower. The lower limit of the glass transition temperature of the second block is not particularly limited. For example, the glass transition temperature may be -80 占 폚 or higher, -70 占 폚 or higher, -60 占 폚 or higher, or -55 占 폚 or higher. The block copolymer containing at least two kinds of blocks may form a fine phase separation structure in the pressure sensitive adhesive, for example. Such a block copolymer exhibits an appropriate cohesive force and stress relaxation property in accordance with a change in temperature, and can form a pressure-sensitive adhesive excellent in properties required for optical films such as durability, light-shielding properties and reworkability.

The block copolymer may have a number average molecular weight of 100,000 or more. As used herein, the term number average molecular weight, weight average molecular weight, or molecular weight distribution (PDI) may refer to a converted value for standard polystyrene measured by GPC (Gel Permeation Chromatograph) as described in the Examples below. In another example, the number average molecular weight of the block copolymer may be at least 200,000, at least 250,000, or at least 300,000. In another example, the block copolymer may be about 800,000 or less, about 650,000 or about 500,000 or less. The number average molecular weight of the first block of the block copolymer may be 15,000 or more. The number average molecular weight of the first block may be up to 150000 in another example.

The ratio (Mw / Mn) of the molecular weight distribution (PDI; Mw / Mn) of the block copolymer, i.e., the weight average molecular weight (Mw) to the number average molecular weight (Mn) may be 1.1 or more and 5 or less, for example.

The block copolymer exhibiting such molecular weight characteristics can exhibit appropriate spacing when forming a fine phase separation structure described later, for example, by chemical and physical crosslinking.

In one example, the block copolymer may be a crosslinkable copolymer having a chemically crosslinkable functional group. Examples of the crosslinkable functional group include a hydroxyl group, a carboxyl group, an isocyanate group, a glycidyl group, an amine group, an alkoxysilyl group or a vinyl group, and in general, a hydroxyl group or a carboxyl group can be used.

The crosslinkable functional group may be present in any one of the first block and the second block, or may be present in both of them. And may be included in the second block when included in any one block. In one example, the first block having a high glass transition temperature may not contain a crosslinkable functional group, and the second block may contain a crosslinkable functional group. When a crosslinkable functional group is included in the second block, the pressure-sensitive adhesive exhibits appropriate cohesive force and stress relaxation property in accordance with temperature change, thereby forming a pressure-sensitive adhesive excellent in physical properties required for optical films such as durability, light- can do.

The kind of the monomer forming the first or the second block in the block copolymer is such that the crosslinkable functional group is introduced at the proper position by the combination of the respective monomers and the glass transition temperature of each block and the number average molecular weight of the copolymer are appropriately controlled And is not particularly limited.

In one example, the first block and the second block exhibit immiscible properties so that the block copolymer can properly form a physical cross-linking structure together with chemical cross-linking by the cross-linkable functional group. Lt; / RTI > To this end, for example, the molecular weight characteristics as described above can be controlled and, if necessary, the ratio between the monomers or blocks forming each block can be adjusted as follows. For example, it is possible to realize a glass transition temperature range and a fine-phase-separated structure as described above by appropriately selecting the kinds and combinations of the monomers forming the first block and the second block.

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 may be used. In one example, considering the control of cohesion, glass transition temperature and tackiness, alkyl (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 Methacrylate may be used. 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. As the monomer forming the first block in consideration of the ease of controlling the glass transition temperature and the like, though not particularly limited, methacrylic acid ester monomers such as methacrylic acid ester 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 second block of the block copolymer includes, for example, 90 parts by weight to 99.9 parts by weight of a (meth) acrylic acid ester monomer and polymerized units derived from 0.1 to 10 parts by weight of a copolymerizable monomer having a crosslinkable functional group can do. In the present specification, the unit weight portion may mean the ratio of the weight between each component. For example, as described above, the second block includes polymerized units derived from 90 to 99.9 parts by weight of the (meth) acrylic acid ester monomer and 0.1 to 10 parts by weight of the copolymerizable monomer having a crosslinkable functional group (A: B) based on the weight of the (meth) acrylic acid ester monomer (A) forming the polymerized unit of the second block and the copolymerizable monomer (B) having a crosslinkable functional group is 90 to 99.9: 0.1 to 10, respectively.

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. The (meth) acrylic acid ester monomer forming the second block in consideration of the ease of controlling the glass transition temperature and the like is not particularly limited, but examples of the monomer described above include acrylic acid ester monomers such as acrylic acid ester monomers having 1 to 20 carbon atoms, Alkyl acrylates 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.

Examples of the copolymerizable monomer having a crosslinkable functional group include a copolymerizable monomer having a moiety copolymerizable with other monomers contained in the block copolymer such as the above (meth) acrylic acid ester monomer, and having a crosslinkable functional group By using the monomer, the pressure-sensitive adhesive exhibits appropriate cohesive force and stress relaxation property according to the temperature change, and can form a pressure-sensitive adhesive having excellent endurance reliability, light-shielding property, workability and the like. In one example, the crosslinkable functional group, for example, a hydroxy group and the like can be used. In this case, the antistatic agent having a functional group such as a hydroxy group contained in the pressure sensitive adhesive has a uniform distribution, Can be minimized.

In the production of pressure-sensitive adhesives, a variety of copolymerizable monomers having the above-mentioned crosslinkable functional groups are known, and all of these monomers can be used in the polymer. Examples of the copolymerizable monomer having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) Hydroxyalkyl (meth) acrylate or 2-hydroxypropyleneglycol (meth) acrylate such as hydroxyalkyl (meth) acrylate or 8-hydroxyoctyl (Meth) acrylate, and the like can be used, but the present invention is not limited thereto. Hydroxyalkyl acrylate or hydroxyalkylene glycol acrylate among the above monomers may be used in consideration of reactivity with other monomers forming the second block and easiness of controlling the glass transition temperature and the like. no.

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 be formed such that the weight ratio (first block: second block) of the first block and the second block is 1:99 to 50:50, for example, for realizing an appropriate microstructure , Suitably the ratio (first block: second block) may be selected to be from 5:95 to 35:65.

For example, the block copolymer may comprise from 1 to 50 parts by weight of the first block and from 50 to 99 parts by weight of the second block, or from 5 to 35 parts by weight of the first block and from 65 to 95 parts by weight of the second block . In the present application, the term " weight portion " may mean a ratio of the weight between each component.

In one example, the block copolymer may be a diblock copolymer comprising the 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), 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 block polymer may be cross-linked by, for example, chemical or physical crosslinking to form a sphere, a cylinder, a gyroid, and a lamellar phase through a fine phase separation phenomenon. When the image of the surface of the fine phase separation film is imaged using an atomic force microscope (AFM), the type of the phase can be grasped. The kind of the block polymer is not particularly limited, but when the spear phase is obtained, the adhesive property and the physical crosslinking property as the pressure sensitive adhesive can be most excellently realized.

The first and second blocks of the block copolymer may be formed such that the average spacing between phases in the fine phase-separated structure is 45 nm or more. For example, the image periodicity obtained through the AFM image described above can be calculated through a two-dimensional power spectral intensity (PSD) analysis, and the average spacing between the hard domains obtained at this time can be measured. The block polymer of the present invention may have a spacing value of 45 nm or more, or may be in a range of 70 nm to 150 nm. In addition to the heat resistance durability required in such cases, when the polarizing plate deformed at high temperature and high humidity is strongly shrunk under normal temperature and humidity conditions, Durability can be satisfied. When the spacing is less than 45 nm, especially at room temperature and low humidity, durability can not be satisfied. When the spacing is larger than 150 nm, it is difficult to realize realization, and there is a possibility that physical bridging point is excessively far away.

The crosslinkable composition may further comprise a crosslinking agent capable of crosslinking the block copolymer. 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.

Examples of such a crosslinking agent include an isocyanate crosslinking agent, an epoxy crosslinking agent, an aziridine crosslinking agent or a metal chelate crosslinking agent, 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 cross-linking composition may contain one or more of the above-mentioned cross-linking agents, but the cross-linking agents that can be used are not limited thereto.

The multifunctional crosslinking agent may be contained in the crosslinkable composition in an amount of 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 strength, And durability can be kept excellent.

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 (1) or (2) can be used.

 [Chemical Formula 1]

(R ₁ ) _n Si (R ₂ ) _(4-n)

 (2)

(R ₃ ) _n Si (R ₂ ) _(4-n)

Wherein R ₁ is a beta-cyanoacetyl group or a beta-cyanoacetylalkyl group, R ₃ is an acetoacetyl group or an acetoacetylalkyl group, R ₂ is an alkoxy group, and n is an integer of 1 to 3 ≪ / RTI >

In the general formula (1) or (2), 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 (1) or (2), 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 linear, Can be.

In Formula 1 or 2, n may be, for example, 1 to 3, 1 to 2, or 1.

Examples of the compound represented by the general formula (1) or (2) include 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 block copolymer, and the desired properties may be effectively imparted to the pressure-sensitive adhesive within this range .

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 further include, if necessary, at least one additive selected from the group consisting of 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 crosslinkable composition may have a gel fraction of 80% by weight or less after implementing the crosslinked structure. The gel fraction can be calculated by the following general formula (1).

 [Formula 1]

Gel fraction (%) = B / A x 100

In the general formula (1), A represents the mass of the crosslinkable composition that implements the crosslinked structure, and B represents the mass of the crosslinkable composition of the mass A in a mesh of a size of 200 mesh, This indicates the dry weight of insoluble fractions collected after 72 hours of immersion.

By maintaining the gel fraction at 80 wt% or less, workability, durability and reworkability can be maintained. The lower limit of the gel fraction of the crosslinkable composition is not particularly limited, and may be, for example, 0% by weight. However, when the gel fraction is 0 wt%, it does not mean that crosslinking has not proceeded at all in the crosslinkable composition. For example, in a crosslinkable composition having a gel fraction of 0% by weight, a crosslinkable composition or crosslinking in which crosslinking has not proceeded at all has progressed to a certain extent, but the degree of crosslinking is low, And may also include leaks.

The crosslinkable composition may be a pressure-sensitive adhesive 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 is a crosslinkable composition for a polarizing plate, and may be a crosslinkable composition used for adhering a polarizing film to a liquid crystal panel.

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, 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 state of realizing a crosslinked structure. Examples of the optical film include a polarizing film, 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 polarizing film in the adhesive optical laminate.

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

A polarizing film is a functional film capable of extracting only light vibrating in one direction from incident light while vibrating in various directions. Such a polarizing film 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 polarizing film 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 polarizing film is formed by a process of stretching a polyvinyl alcohol resin film as described above (e.g., uniaxially stretching), a process of dyeing a polyvinyl alcohol resin film with a dichroic dye and adsorbing the dichroic dye, A step of treating the adsorbed polyvinyl alcohol based resin film with an aqueous solution of boric acid and a step of water washing after treatment with an aqueous solution of boric acid. 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 polarizing film. 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 plate, a wide viewing 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 as described above is not particularly limited, and for example, a method of directly coating the crosslinkable composition on a polarizing plate or an optical film and curing the crosslinked structure Or a method of forming a crosslinked structure by coating and curing the crosslinkable composition on the release treated surface of a release film and then transferring the crosslinked structure onto a polarizing plate or an optical film.

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

The multifunctional crosslinking agent contained in the crosslinkable composition during the coating process is preferably controlled in such a manner that the crosslinking reaction of the functional groups is not proceeded from the viewpoint of performing a uniform coating process so that the crosslinking agent is cured and hardened The crosslinking structure is formed to improve the cohesive force of the pressure-sensitive adhesive, and the adhesive property and cuttability can be improved.

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 by subsequent curing of the above-mentioned coating is not particularly limited. For example, the coating layer may be appropriately adjusted so that a cross-linking reaction of the block copolymer contained in the coating layer and the multi- A method in which the temperature is maintained at a predetermined temperature, or the like.

The present application is also directed to a display device, for example, an LCD device. An exemplary display 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 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 types of liquid crystal display devices, such as upper and lower substrates, such as color filter substrates or array substrates, are not particularly limited, and configurations known in the art can be employed without limitation.

In the present application, a crosslinkable composition capable of forming a pressure-sensitive adhesive excellent in cohesive force and stress relaxation property and excellent in durability and light-shielding ability can be provided. The crosslinkable composition of the present application can be used for an optical film such as a polarizing plate or the like.

1 is an AFM image of the block copolymer (A3) prepared in Production Example 3 (image size 1 μm × 1 μm)
2 is an AFM image of the block copolymer (B1) prepared in Comparative Preparation Example 1 (image size 1 μm × 1 μm)

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.

1. Evaluation of molecular weight

The number average molecular weight (Mn) and the molecular weight distribution (PDI) were measured using GPC under the following conditions, and the measurement results were converted using a standard polystyrene of Agilent system for the calibration curve.

<Measurement Conditions>

Measuring instrument: Agilent GPC (Agilent 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 μL injection)

2. Evaluation of molecular weight change rate

The number average molecular weight (Mn, A) of the crosslinkable composition before addition of the crosslinking agent and the number average molecular weight (Mn, B) of the crosslinking reaction product after the crosslinking reaction were evaluated according to the following formulas.

&Lt; Evaluation of change in molecular weight &

Molecular weight change ratio (%) = 100 x (B-A) / A

3. Spacing  evaluation

Images were obtained by atomic force microscope (AFM) and calculated by using 2 dimensional power spectral intensity (PSD) analysis software to obtain the phase spacing in the fine phase separation structure.

&Lt; AFM measurement condition >

Instrument: Multimode AFM (Bruker, multimode 8)

Measurement parameters: Mode: Soft Tapping in Air, Samples / line: 256 x 256, Scan rate: 0.3 to 0.6 Hz

AFM probe specification: Silicon AFM probes with aluminum

Material: Silicon, Resonance Frequency: 250 to 390 kHz, Force Constant: 42 N / m

Thickness: 3.5 to 4.5 탆, Length: 125 to 5 탆, Width: 25 to 35 탆

Software used: Nanoscope8.15

4. Evaluation of durability

The pressure-sensitive polarizing plate prepared in Examples or Comparative Examples was cut to a width of 320 cm and a length of 180 cm to prepare a specimen. The prepared specimen is attached to a commercial LCD panel having a thickness of about 0.7 mm via a pressure-sensitive adhesive layer, and the panel with the specimen is stored at 50 ° C and 5 atm for about 20 minutes to prepare a sample. After the prepared sample was maintained at 90 캜 for 300 hours, the occurrence of bubbles or peeling at the adhesive interface of the pressure-sensitive adhesive layer was observed, and the durability was evaluated according to the following criteria. Thereafter, after storage for one month under a room temperature and low humidity condition of 25 ° C and 25% humidity, the occurrence of bubbles or peeling at the adhesive interface of the pressure-sensitive adhesive layer is further observed to evaluate the low temperature and humidity durability.

<Durability Evaluation Standard>

A: When bubbles and peeling phenomenon are not observed

B: When bubbles and / or peeling phenomenon is slightly observed

C: When a large amount of bubbles and / or peeling phenomenon is observed

5. Estimation of glass transition temperature

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

<Formula>

1 / Tg = SWn / Tn

In the above formula, Wn represents the weight fraction of the monomer used in each block and the like, and Tn represents the glass transition temperature which appears when the monomer used 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.

Manufacturing example  1. Preparation of block copolymer (A1)

200 g of MMA (Methyl methacrylate), 200 g of ethyl acetate and 1.39 g of ethyl 2-bromoisobutyrate were placed in a flask, and the flask was sealed. Then, oxygen was bubbled through nitrogen bubbling for about 40 minutes. After removal of oxygen, the flask was placed in an oil bath heated to 65 ° C and 0.036 g of CuBr ₂ and 0.094 g of TPMA (tris (2-pyridylmethyl) amine) were added to a separately prepared 10 mL vial in 2 mL of DMF -dimethylformamide), and then an ATRP catalyst solution in which oxygen was removed through nitrogen bubbling was charged into the flask. Then, 0.65 g of Sn (EH) ₂ (tin (II) octoate) was added as a catalyst reducing agent to initiate the reaction. The reaction was terminated at a monomer conversion of about 70%, and a macroinitiator having a Mn of 20,000 and a molecular weight distribution of 1.24 was prepared. 635 g of n-BA (n-butyl acrylate), 12.7 g of 4-HBA (4-hydroxybutyl acrylate) and 455 g of ethyl acetate were added to 50 g of the macroinitiator purified through a methanol precipitation process, Oxygen was removed by bubbling with nitrogen for 60 minutes. Under the nitrogen atmosphere, while maintaining the reaction temperature at about 65 ° C, a catalyst solution containing 0.070 g of CuBr ₂ , 0.18 g of TPMA and 5 mL of DMF was added and 1.25 g of Sn (EH) ₂ was added to initiate the reaction. When the reaction conversion reached about 70%, the reaction was terminated to produce a block copolymer solution having a molecular weight (Mn) of 110,000 and a molecular weight distribution (Mw / Mn) of 2.06. The weight ratio of the first block to the second block is about 10:90. The spacing measured by AFM was 62 nm.

Manufacturing example  2. Preparation of block copolymer (A2)

200 g of MMA (methyl methacrylate), 200 g of ethyl acetate and 0.65 g of ethyl 2-bromoisobutyrate were charged into a flask, and the reaction was carried out as described in Preparation Example 1, below. The reaction was terminated at a monomer conversion of 73% to prepare a macroinitiator (MI) having a molecular weight (Mn) of about 34,000 and a molecular weight distribution (Mw / Mn) of 1.38. 635 g of n-BA (n-butyl acrylate), 12.7 g of 4-HBA (4-hydroxybutyl acrylate) and 455 g of ethyl acetate were added to 50 g of the macroinitiator purified through a methanol precipitation process, The reaction was carried out in the same manner as in Example 1. When the reaction conversion rate reached about 70%, the reaction was terminated to produce a block copolymer solution having a molecular weight (Mn) of 200,000 and a molecular weight distribution (Mw / Mn) of 2.60. The weight ratio of the first block to the second block is about 10:90. The spacing measured by AFM was 87 nm.

Manufacturing example  3. Preparation of block copolymer (A3)

200 g of MMA (methyl methacrylate), 200 g of ethyl acetate and 0.49 g of ethyl 2-bromoisobutyrate were placed in a flask, and a macro initiator was prepared under the same conditions as in Production Example 1 above. The reaction was terminated at a monomer conversion of about 80%, and a macroinitiator having a Mn of 47,000 and a molecular weight distribution of 1.35 was prepared. 350 g of n-BA (n-butyl acrylate), 7.0 g of 4-HBA (4-hydroxybutyl acrylate) and 260 g of ethyl acetate were added to 50 g of the macroinitiator purified through a methanol precipitation process, Oxygen was removed by bubbling with nitrogen for 60 minutes. Under the nitrogen atmosphere, the reaction solution was mixed with 0.040 g of CuBr ₂ , 0.10 g of TPMA and 2.8 mL of DMF, and 0.72 g of Sn (EH) ₂ was introduced to initiate the reaction. When the conversion rate reached 80%, the reaction was terminated to produce a block copolymer solution having a molecular weight (Mn) of 210,000 and a molecular weight distribution (Mw / Mn) of 2.40. The weight ratio of the first block to the second block is about 15:85. The spacing measured by AFM was 93 nm.

Manufacturing example  4. Preparation of block copolymer (A4)

511 g of n-BA, 10.2 g of 4-HBA and 370 g of ethyl acetate were added to 50 g of the macroinitiator prepared in Preparation Example 3, and the mixture was poured into a flask and bubbled with nitrogen for about 60 minutes to remove oxygen. Under the nitrogen atmosphere, while maintaining the reaction temperature at about 65 ° C, a catalyst solution containing 0.056 g of CuBr ₂ , 0.14 g of TPMA and 5 mL of DMF was added, and a 2% ethyl acetate solution containing 0.41 g of AIBN was added to the reaction Lt; / RTI &gt; When the reaction conversion reached about 75%, the reaction was terminated to produce a block copolymer solution having a molecular weight (Mn) of 230,000 and a molecular weight distribution (Mw / Mn) of 2.82. The weight ratio of the first block to the second block is about 11:89. The spacing measured by AFM was 122 nm.

compare Manufacturing example  1. Preparation of block copolymer (B1)

180 g of n-BA (n-butyl acrylate), 3.6 g of 4-HBA (4-hydroxybutyl acrylate) and 150 g of ethyl acetate were added to 50 g of the macroinitiator prepared in Preparation Example 1, Lt; RTI ID = 0.0 &gt; g / min &lt; / RTI &gt; CuBr while maintaining the reaction temperature in a nitrogen atmosphere at about _{65 ℃ 2 0.023 g, TPMA 0.060} g and put into a catalyst solution a mixture of DMF 1.7 mL and, AIBN 0.17 g The reaction by introducing a 2% ethyl acetate solution containing Lt; / RTI &gt; When the reaction conversion reached about 75%, the reaction was terminated to produce a block copolymer solution having a molecular weight (Mn) of 77,000 and a molecular weight distribution (Mw / Mn) of 1.70. In the above, the weight ratio of the first block to the second block is about 25:75. The spacing measured by AFM was 41 nm.

compare Manufacturing example  2. Preparation of random copolymer (B2)

The random copolymer B2 into which only chemical crosslinking was introduced was prepared as follows. 200 g of n-BA, 4.0 g of 4-HBA and 600 g of ethyl acetate were put into a flask, and nitrogen was bubbled therein for 60 minutes to remove dissolved oxygen. When the reaction temperature reaches 65 ^° C, 2% ethyl acetate solution containing 0.10 g of AIBN is added to initiate the reaction. When the reaction conversion was about 70%, the reaction was terminated to obtain a random copolymer having a molecular weight (Mn) of 220,000 and a molecular weight distribution of 4.52.

Example  One.

To 100 parts by weight of the block copolymer (A1) prepared in Preparation Example 1, about 0.1 part by weight of a crosslinking agent (TDI, toluene diisocyanate) and about 0.01 part by weight of a known crosslinking catalyst were blended to prepare a crosslinkable composition. Subsequently, the composition was coated on a release-treated PET (poly (ethylene terephthalate)) film to a thickness of about 25 mu m and dried at 120 DEG C for about 3 minutes. The dried layer thus formed was transferred to one surface of a known polarizing plate to produce a pressure-sensitive polarizing plate.

Example  2 to 4.

A pressure-sensitive polarizing plate was prepared in the same manner as in Example 1, except that the block copolymers (A2, A3, A4) prepared in Production Examples 2 to 4 were used.

Comparative Example  1 to 2.

A pressure-sensitive polarizing plate was produced in the same manner as in Example 1, except that the block copolymers (B1, B2) prepared in Comparative Production Examples 1 and 2 were used.

The results of evaluating physical properties of the crosslinkable compositions and the like of the examples and comparative examples are summarized in Table 1 below.

Example Comparative Example One 2 3 4 One 2 Block copolymer type A1 A2 A3 A4 B1 B2 spacing 62 nm 87nm 93 nm 122 nm 41nm - High temperature endurance characteristics A A A A A B Durability at room temperature and humidity A A A A B C

From the results shown in Table 1, when the physical crosslinking structure is added to the chemical crosslinking structure, excellent durability properties can be obtained at higher temperature than the random crosslinking copolymer obtained only by chemical crosslinking. In addition, when the spacing value is more than 45 nm, excellent durability characteristics are exhibited not only at high temperature durability but also at a room temperature and low humidity condition even when strong polarizer shrinkage occurs. On the other hand, when the spacing value is lower than 45 nm, the distance between the hard blocks can not sufficiently emit external stress due to the polarizing plate shrinkage, resulting in a large amount of combs and bubbles under the room temperature and low humidity conditions.

Claims (6)

A block copolymer having a first block having a glass transition temperature of 30 DEG C or higher and a second block having a glass transition temperature of 0 DEG C or lower and having a chemically crosslinkable functional group; And a crosslinking agent capable of crosslinking the block copolymer,
Crosslinked to form a phase separation structure of a sphere, a cylinder, a gyroid or a lamellar, and the average phase distance of the phase separation structure is 45 nm or more. The crosslinkable composition according to claim 1, wherein the chemical crosslinkable functional group is a hydroxyl group, a carboxyl group, an isocyanate group, a glycidyl group, an amine group, an alkoxysilyl group or a vinyl group. The crosslinkable composition according to claim 1, wherein the phase separation structure is a sphere structure. The crosslinkable composition according to claim 1, wherein the average phase distance is from 70 nm to 150 nm. The crosslinkable composition according to claim 1, wherein the crosslinking agent is an isocyanate crosslinking agent, an epoxy crosslinking agent, an aziridine crosslinking agent or a metal chelate crosslinking agent. Optical film; And a pressure-sensitive adhesive layer formed on one or both surfaces of the optical film, wherein the pressure-sensitive adhesive layer comprises the crosslinkable composition of claim 1 which is crosslinked.

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