KR20180033697A - Pressure sensitive adhesive composition - Google Patents

Abstract

The present invention relates to a pressure-sensitive adhesive composition, a protective film, an optical laminate, a pressure-sensitive type polarizing plate and a display device. The present application can provide a pressure-sensitive adhesive composition which is excellent in heat resistance and resistance to endurance against moisture and heat, and can minimize light spots even when exposed under severe conditions such as high temperature or high temperature and high humidity.

Description

[0001] PRESSURE SENSITIVE ADHESIVE COMPOSITION [0002]

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

Background Art [0002] A liquid crystal display device (hereinafter, referred to as " LCD device ") includes a liquid crystal panel including a liquid crystal component injected between two transparent substrates, and a liquid crystal panel including, for example, a polarizing film, Film. ≪ / RTI > At this time, a pressure-sensitive adhesive is mainly used for laminating the optical films or attaching the optical films to the liquid crystal films.

On the other hand, an acrylic polymer, a rubber, a urethane resin, a silicone resin, or an ethylene vinyl acetate (EVA) resin can be used as the pressure sensitive adhesive. In view of transparency and resistance to oxidation or yellowing, Is used. However, in order to use an acrylic copolymer-containing pressure-sensitive adhesive for application to an optical film, improvement in cohesion, adhesive force, reworkability, low light leakage property, stress relaxation property and the like is still required.

One object of the present invention is to provide a pressure-sensitive adhesive composition, an optical laminate, a polarizing plate and a display device.

Another object of the present invention is to provide a pressure-sensitive adhesive composition improved in durability and reliability at high temperature and / or high humidity under severe conditions, and an optical product comprising the same.

The above and other objects of the present application can be all attained by the present application which is described in detail below.

In one example of this application, the present application relates to a pressure sensitive adhesive composition. The adhesive composition may include a block copolymer. The term " block copolymer " in this application may refer to a copolymer comprising blocks of different polymerized monomers.

The block copolymer may include a first block having a glass transition temperature of 50 ° C or higher and a second block having a glass transition temperature of -10 ° C or lower. In the present application, the "glass transition temperature" of each block constituting the block copolymer may mean a glass transition temperature measured from a polymer formed only of the monomers formed in the block.

In one example, the glass transition temperature of the first block may be at least 50 ° C, at least 60 ° C, at least 70 ° C, at least 80 ° C, or at least 90 ° C. The upper limit of the glass transition temperature of the first block is not particularly limited, but may be 200 占 폚 or lower, for example.

In one example, the glass transition temperature of the second block may be below -10 占 폚, below -20 占 폚, below -30 占 폚, below -40 占 폚, or below -50 占 폚. The lower limit of the glass transition temperature of the second block is not particularly limited, but may be, for example, -80 ° C or higher.

The copolymer of the present application including both of the two blocks satisfying the above glass transition temperature range can form a fine phase separation structure in the pressure sensitive adhesive. Such block copolymers exhibit appropriate cohesive strength and stress relaxation properties in accordance with temperature changes, and thus form a pressure-sensitive adhesive which maintains excellent physical properties required for optical films such as interface adhesion, endurance reliability, light-shielding properties, and reworkability I can do it.

In one example, the Number Average Molecular Weight (Mn) of the first block of the block copolymer may range from 2,500 to 150,000. The number average molecular weight of the first block may be, for example, the number average molecular weight of the polymer produced by polymerizing only the monomer forming the first block. In the present application, the number average molecular weight (Mn) can be measured according to the method shown in the examples using, for example, GPC (Gel Permeation Chromatograph). More specifically, the number average molecular weight of the first block may range, for example, from 5,000 to 100,000 or from 10,000 to 50,000.

In one example, the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the first block, i.e., the molecular weight distribution (PDI = Mw / Mn) may range from 1.0 to 3.0. More specifically, the molecular weight distribution of the first block may have a lower limit of 1.0 or more, 1.1 or more, 1.2 or more, 1.3 or more, and an upper limit thereof may be 3.0 or less, 2.0 or less, or 1.5 or less.

In one example, the block copolymer may have a number average molecular weight of from 50,000 to 500,000. More specifically, the number average molecular weight of the block copolymer may be 100,000 or more, 130,000 or more, 150,000 or more, or 180,000 or more, and the upper limit may be 300,000 or less, 250,000 or less, 230,000 or less, 200,000 or less, 180,000 or 150,000 or less.

In one example, the molecular weight distribution (PDI = Mw / Mn) of the block copolymer may range from 1.0 to 2.5. More specifically, the lower limit of the molecular weight distribution of the block copolymer may be, for example, 1.3 or more, 1.4 or more, 1.5 or more, 1.6 or more, 1.7 or more, or 1.8 or more, Or less, 2.3 or less, 2.2 or less, 2.1 or less, or 2.0 or less.

When the molecular weight property of the block copolymer is controlled within the above range, physical properties such as interface adhesion, endurance reliability, antireflection property and reworkability required in the pressure-sensitive adhesive for optical film can be excellent.

The block copolymer may be a crosslinkable copolymer having a crosslinkable functional group. Examples of the crosslinkable functional group include a hydroxyl group, a carboxyl group, an epoxy group, an isocyanate group or a nitrogen-containing functional group.

When the functional group includes a crosslinkable functional group, the functional group may be contained in either the first block or the second block, or may be included in both the first and second blocks.

In one example, the crosslinkable functional group may be included in the second block. In this case, the crosslinkable functional group is not included in the first block but can be included only in the second block. Provided is a pressure-sensitive adhesive which exhibits proper cohesive force and stress relaxation property in accordance with a temperature change and contains excellent physical properties such as interface adhesion, endurance reliability, light-shielding property and reworkability when a crosslinkable functional group is included in the second block .

As long as the glass transition temperature range and the molecular weight range of each of the above-mentioned blocks can be ensured, the kind of the monomers constituting the first block and the second block is not particularly limited.

In one example, the first block may be a polymer of a (meth) acrylic acid ester monomer. More specifically, the first block may contain a polymerized unit derived from a (meth) acrylic acid ester monomer. In the present application, the fact that a monomer is contained in a polymer or block in a polymerized unit may mean that the monomer undergoes a polymerization reaction to form the skeleton of the polymer or block, for example, a main chain or a side chain. As the (meth) acrylic acid ester monomer used for forming the first block, for example, alkyl (meth) acrylate may be used. In one example, considering the control of the cohesion, the glass transition temperature and the tackiness, it is preferable to use an alkyl (meth) acrylate having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms and 1 to 4 carbon atoms ) Acrylate may be used in the first block formation. 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 Acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate and lauryl (meth) acrylate. In order to secure the above glass transition temperature range, More than one may be used in the first block formation.

In one example, 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 is used in consideration of ease of controlling the glass transition temperature . For example, the first block may have a polymerization unit derived from 60 to 80 parts by weight of an alkyl methacrylate having an alkyl group having 1 to 3 carbon atoms, From 20 to 40 parts by weight of an alkyl methacrylate having an alkyl group of 1 to 20 carbon atoms. The term " part by weight " in the present application may mean a weight ratio between the components. For example, the first block contains 60 to 80 parts by weight of alkyl methacrylate (A) having an alkyl group of 1 to 3 carbon atoms and 20 to 40 parts by weight of alkyl methacrylate (B) having an alkyl group of 4 to 10 carbon atoms The term "derived polymerization unit" is meant to mean that the weight ratio of the monomer (A) and the monomer (B) forming the polymerized unit of the first block is in the range of 60 to 80:20 to 40.

In one example, the second block may be a polymer of (meth) acrylic acid ester monomers. Specifically, the first block may include a polymerized unit derived from a (meth) acrylic acid ester monomer and a polymerization unit derived from a copolymerizable monomer having a crosslinkable functional group. The content of the monomer used for forming the second block is not particularly limited. For example, the second block may contain 80 to 99.9 parts by weight of a (meth) acrylic acid ester monomer and 0.1 to 20 parts by weight of a copolymerizable monomer having a crosslinkable functional group And may comprise polymerized units derived from parts by weight.

In one example, considering the ease of controlling the glass transition temperature, it is preferable to use a monomer having a carbon number of 1 to 20, a number of carbon number of 1 to 16, a number of carbon number of 1 to 12, a number of carbon number of 1 to 8, An alkyl acrylate having an alkyl group of 4 may be used for the second block formation. In consideration of reactivity during polymerization and the like, the second block preferably contains 80 to 99.9 parts by weight of an alkyl acrylate having an alkyl group having 1 or 4 carbon atoms and 0.1 to 20 parts by weight of a copolymerizable monomer having a crosslinkable functional group May comprise polymerized units derived from the moiety. When the above composition is satisfied, it is possible to provide a pressure-sensitive adhesive capable of minimizing light leakage while ensuring physical properties such as interface adhesion, durability and proper cohesive force.

The copolymerizable monomer having a crosslinkable functional group contained in the second block has a site that can be copolymerized with another monomer contained in the block copolymer such as the alkyl acrylate monomer, It may be a monomer having a functional group. As the crosslinkable functional group contained in the copolymerizable monomer, the above-mentioned hydroxyl group, carboxyl group, epoxy group, isocyanate group or nitrogen-containing functional group may be used.

Such a monomer having a crosslinkable functional group is variously known in the adhesive production field, and known monomers can be used without limitation. For example, when the copolymerizable monomer having a crosslinkable functional group is a monomer having a hydroxy group, Examples of such monomers include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl Hydroxyalkyl (meth) acrylates such as hydroxyoctyl (meth) acrylate; (Meth) acrylate such as 2-hydroxyethyleneglycol (meth) acrylate or 2-hydroxypropyleneglycol (meth) acrylate, and the like. It is not.

The first block and / or the second block may further include any comonomer, if necessary, for controlling the glass transition temperature and the like, and the monomer may be included as a polymerization unit. 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, in each block.

In one example, the block copolymer may comprise from 5 parts by weight to 50 parts by weight of the first block and from 50 parts by weight to 95 parts by weight of the second block. By adjusting the ratio of the weight between the first block and the second block as described above, it is possible to provide a pressure-sensitive adhesive composition and a pressure-sensitive adhesive having excellent physical properties.

In one example, the block copolymer may be a diblock copolymer including the first and second blocks, i.e., a block copolymer containing only two blocks of the first block and the second block. have. By using the diblock copolymer, the adhesive property of the interface, the durability reliability, the stress relaxation property, the reworkability, and the like can be excellently maintained.

The method for producing the block copolymer is not particularly limited, and a known method can be used. For example, the block polymer can be polymerized by an LRP (Living Radical Polymerization) method. Specifically, anionic polymerization in which an organic rare earth metal complex is used as a polymerization initiator, or an organic alkali metal compound is used as a polymerization initiator in the presence of an inorganic acid salt such as a salt of an alkali metal or an alkaline earth metal, (ATRP) using an atom transfer radical polymerization agent as a polymerization initiator, and an atom transfer radical polymerization agent as a polymerization initiator, while generating electrons (ATRP), initiators for continuous activator regeneration (ATR), ATRP, and inorganic reductant reversible addition-cleavage (ATRP), which perform polymerization under an organic or inorganic reducing agent Reversible addition-cleavage chain transfer using chain transfer agent (RAFT), or a method of using an organic tellurium compound as an initiator. Among these methods, an appropriate method may be selected to produce the block copolymer.

The pressure-sensitive adhesive composition of the present application may include one or more crosslinking agents capable of reacting with the crosslinkable functional group of the block copolymer to form a chemical crosslinking structure. As the crosslinking agent, a multifunctional crosslinking agent having two or more functional groups capable of reacting with the crosslinkable functional group contained in the block copolymer may be used. Non-limiting examples of such crosslinking agents include isocyanate crosslinking agents, epoxy crosslinking agents, aziridine crosslinking agents and metal chelate crosslinking agents.

In one example, when the crosslinkable functional group is a hydroxy group, an isocyanate crosslinking agent may be used as the polyfunctional crosslinking agent. Examples of the isocyanate crosslinking agent include, but are not limited to, tolylene diisocyanate, xylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isoboron diisocyanate, tetramethylxylene diisocyanate and naphthalene diisocyanate. Diisocyanate compounds; Or a compound obtained by reacting the diisocyanate compound with a polyol. As the polyol, trimethylolpropane and the like may be used.

In one example, the multifunctional crosslinking agent may be included in the adhesive composition in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the block copolymer. More specifically, the lower limit of the crosslinking agent content may be 0.03 parts by weight or more, 0.05 parts by weight or more, or 0.10 parts by weight or more, and the upper limit may be 5 parts by weight or less, 3 parts by weight or less, or 1.0 parts by weight or less. In this range, the degree of crosslinking of the block copolymer can be appropriately controlled, and the gel fraction, cohesion, adhesion, durability and the like of the pressure-sensitive adhesive can be kept excellent.

Two kinds of silane coupling agents can be used simultaneously in the adhesive composition of the present application. The silane coupling agent is known as the most widely used coupling agent. However, when an excessive amount of silane coupling agent is used, bubbles are generated at the adhesive interface under severe conditions such as high temperature or high humidity conditions, and peeling or peeling phenomenon . As a result, the heat durability of the product and the durability against moisture and heat are deteriorated, and consequently the light spot phenomenon is increased. Therefore, in the prior art, in view of the above problems, it has been common to use only a very small amount of only one kind of silane coupling agent.

Alternatively, the adhesive composition of the present application may contain two kinds of silane coupling agents having different functional groups in a specific amount range. Specifically, the pressure-sensitive adhesive composition of the present application can simultaneously contain a first silane coupling agent (A) having an isocyanate group and a second silane coupling agent (B) having a functional group other than an isocyanate group. In this case, the first silane coupling agent (A) may contain, in addition to the alkoxy group, only an isocyanate group as a functional group, and the second silane coupling agent (B) may include the following functional groups except an isocyanate group.

The first silane coupling agent (A) has an effect that the isocyanate group contained in the first silane coupling agent binds to the crosslinkable functional group of the block copolymer to bind the silane coupling agent to the block copolymer. Since the binding by the first silane coupling agent occurs at a higher rate than the binding of the block copolymer with the second silane coupling agent (B) having a functional group other than the isocyanate group, Can be improved. As mentioned above, in the case of the second silane coupling agent (B), surplus silane coupling agent bleeds to the surface of the pressure-sensitive adhesive in excess use, thereby lowering durability and reliability. However, as in the present application, when the first silane coupling agent (A) is used in the specific content range mentioned below, the silane coupling agent bound to the block copolymer can be more effectively adhered to the adhesive agent and the glass base material. Therefore, it is possible to exhibit high adhesiveness and adhesion stability under heat and moisture and heat-resistant conditions, and to improve the reliability of endurance against heat and humidity, as compared with the case where the second silane coupling agent (B) having a functional group other than an isocyanate group alone is used .

In one example, the first silane coupling agent (A) is a compound containing an isocyanate group and at least one alkoxy group, such as, for example, 3-isocyanatepropyltriethoxysilane or 3-isocyanatepropyltrimethoxysilane Lt; / RTI > The first silane coupling agent (A) may be represented by the following general formula (1).

[Chemical Formula 1]

In the formula (1), R ₁ to R ₃ may each independently be a hydroxyl group, an alkoxy group having 1 to 20 carbon atoms, or an alkyl group having 1 to 20 carbon atoms, and at least one of R ₁ to R ₃ is a A is an alkylene group, and R < ₄ > is an isocyanate group. In one example, A may be an alkylene group having 1 to 10 carbon atoms.

In one example, the alkoxy group may be a linear, branched or cyclic alkoxy group, and the alkyl group bonded to the oxygen of the alkoxy group may have 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, Or an alkyl group having 1 to 4 carbon atoms.

In one example, the first silane coupling agent (A) may be included in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the block copolymer. Specifically, the lower limit of the content of the first silane coupling agent may be 0.01 part by weight, 0.1 part by weight, 0.5 part by weight, 1 part by weight or 3 parts by weight and the upper limit may be 10 parts by weight, 5 parts by weight, or 1.5 parts by weight Can be.

The second silane coupling agent (B) may be a compound having a functional group other than an isocyanate group. For example, the second silane coupling agent (B) may include any one of an epoxy group, a thiol group, an amino group, a vinyl group, an epoxy group, a beta-cyanoacetyl group, an acetoacetyl group or a halogen element.

In one example, as the second silane coupling agent (B), a compound having a beta-cyano group represented by the following formula (2) or a compound having an acetoacetyl group represented by the following formula (3) may be used.

(2)

(R ₅ ) _n Si (R ₆ ) _(4-n)

(3)

(R ₇ ) _n Si (R ₆ ) _(4-n)

In the general formula (2) or (3), R ₅ is a beta-cyanoacetyl group or a beta-cyanoacetylalkyl group, R ₇ is an acetoacetyl group or an acetoacetylalkyl group, R ₆ is an alkoxy group, Number.

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

Examples of the compound represented by Formula 2 or 3 include acetoacetylpropyltrimethoxysilane, acetoacetylpropyltriethoxysilane, betacyanoacetylpropyltrimethoxysilane, or betacyanoacetylpropyltriethoxysilane. But is not particularly limited thereto.

In one example, the second silane coupling agent (B) may be included in the range of 0.01 to 10 parts by weight based on 100 parts by weight of the block copolymer. Specifically, the lower limit of the content of the second silane coupling agent may be 0.01 parts by weight or more, 0.1 parts by weight, or 0.2 parts by weight or more and the upper limit may be 10 parts by weight or less, 5 parts by weight or less, 3 parts by weight or less, Or less.

In one example, the content ratio (A / B) of the first silane coupling agent (A) and the second silane coupling agent (B) can be controlled in the range of 2 to 30. When the content ratio (A / B) is less than 2, the effect of addition of the first silane coupling agent is insignificant and it is difficult to obtain the effect of improving the durability under adverse conditions. When the content ratio A / B exceeds 30 , Since the isocyanate group of the first silane coupling agent (A) participates in the crosslinking, durability may be deteriorated due to the occurrence of over-curing.

The pressure-sensitive adhesive composition may further include 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 included in the adhesive composition in an amount of 100 parts by weight or less based on 100 parts by weight of the block copolymer.

The adhesive composition may further include additives such as an epoxy resin, a curing agent, an ultraviolet stabilizer, an antioxidant, a colorant, a reinforcing agent, a filler, a defoamer, a surfactant or a plasticizer. The specific kind or content of the additive is not particularly limited.

In one example of the present application, the pressure-sensitive adhesive composition may be a pressure-sensitive adhesive composition for an optical film. The pressure-sensitive adhesive 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 compensation film or a brightness enhancement film, And can be used for adhering to an adherend. In one example, the pressure-sensitive adhesive composition is a pressure-sensitive adhesive composition for a polarizing plate, and may be a pressure-sensitive adhesive composition used for adhering a polarizing film to a liquid crystal panel.

In another example, the present application is directed to a pressure-sensitive adhesive optical laminate. Exemplary optical stacks include optical films; And a pressure-sensitive adhesive layer present on at least one side 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 pressure-sensitive adhesive composition of the present invention described above. The pressure-sensitive adhesive composition may be contained in the pressure-sensitive adhesive layer in a state of implementing a crosslinked structure. 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. PET and polyolefin-based films can be used when securing water-shielding properties. When considering durability, acrylic films can be used.

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 of forming the pressure-sensitive adhesive layer on the polarizing plate or the optical film in the present application is not particularly limited. For example, the pressure-sensitive adhesive composition may be directly coated on a polarizing plate or the like and cured to form a crosslinked structure, A method in which the pressure-sensitive adhesive composition is coated and cured on the release-treated surface to form a crosslinked structure, and then the transferred composition is transferred.

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

The crosslinking agent contained in the adhesive composition in the coating process is preferably controlled from the viewpoint of performing a uniform coating process so that the crosslinking reaction of the functional groups is prevented from proceeding. To improve the cohesive force of the pressure-sensitive adhesive, and to improve the adhesive property and the cuttability.

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

The method for curing the adhesive composition after coating to form a crosslinked structure is also not particularly limited. For example, the coating layer may be maintained at an appropriate temperature so that a crosslinking reaction between the block copolymer contained in the coating layer and the polyfunctional crosslinking agent may be induced.

The present application is also directed to a display device. 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.

The present application can provide a pressure-sensitive adhesive composition which, when used for optical films, can improve durability reliability under severe conditions such as high temperature and high humidity.

Hereinafter, the adhesive composition of the present application will be described in detail through examples and comparative examples. However, the scope of the present application 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 block or block 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. Glass transition temperature

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

≪ Formula A >

1 / Tg =? Wn / Tn

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

3. Evaluation of durability

The polarizing plates prepared in Examples and Comparative Examples were cut to a width of about 180 mm and a length of about 320 mm, and they were attached to a 19-inch commercial liquid crystal panel. Thereafter, the panel with the polarizing plate was stored for about 20 minutes in an autoclave (50 캜, 5 atm) to prepare a sample.

The heat resistance durability was evaluated by observing the occurrence of bubbles and peeling in accordance with the following criteria after the sample was left at 80 DEG C for 500 hours.

In the case of anti-wet heat resistance, the sample was allowed to stand at 60 ° C and 90% relative humidity for 500 hours, and the occurrence of bubbles and peeling at the adhesive interface was observed and evaluated according to the following criteria.

≪ Heat resistance durability and anti-wet heat durability evaluation standard >

A: No bubbles and peeling occurred

B: Bubbles and / or slight peeling occurred

C: large amount of bubbles and / or peeling occurred

4. Evaluation of bending characteristics

(1) heat resistance Condition  Bending characteristic

Strip measurements (glass bending measurements) were used to evaluate the flexural properties. First, STN sodalime glass for bending (4 x 41 cm ² , 0.4 t) was prepared. If there is no foreign matter, use it without washing. If there is foreign material, clean it with EAc and IPA solvent and dry it with air-gun. Prepare a polarizing plate (coated product) with a pressure-sensitive adhesive on a 3.5 x 40.5 cm ² long MD direction. Attach the specimen using a laminator to the prepared bending glass. After initial measurement, store at 80 ℃ heat-resistant condition for 72 hours. Prepare a device to fix the sample in the chamber as shown below, fix the sample on one side of the bending sample, and measure the distance from the reference point. Prepare three samples for the same prescription and calculate the average value.

(2) Wet heat Condition  Bending characteristic

The flexural properties were measured in the same manner as described above, and the samples prepared in the same manner were stored for 72 hours under a moisture-resistant condition of 60 ° C and 90% relative humidity, and then their flexural properties were measured.

<Fig. Measurement location of Glass Bending (Strip measurement method)>

Preparation of Copolymer

Manufacturing example  1. Preparation of block copolymer (A1)

0.032 g of EBiB (ethyl 2-bromoisobutyrate), 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, nitrogen purged and stirred at about 25 캜 for about 30 minutes, and dissolved oxygen was removed through bubbling. Then 0.002 g of CuBr2, 0.006 g of TPMA (tris (2-pyridylmethyl) amine) and 0.003 g of 2,2'-azobis (2,4-dimethyl valeronitrile) were added to the deoxygenated mixture And the reaction was initiated by immersing the reaction mixture in a reaction tank at about 67 DEG C (polymerization of the first block). A mixture of 111.4 g of methyl acrylate (MA) previously bubbled with nitrogen, 1.1 g of hydroxybutyl acrylate (HBA) and 75 g of ethyl acetate (EAc) was 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 chain extension reaction was carried out (polymerization of the second block). When the conversion of the monomer (BA) reached 80% or more, the reaction mixture was exposed to oxygen, diluted with an appropriate solvent, and the reaction was terminated to prepare a block copolymer. In the above procedure, V-65 was appropriately divided into the reaction completion time points in consideration of the half-life thereof.

Manufacturing example  2 to 5. Preparation of block copolymers (A2 to A5)

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

Manufacturing example  6. Preparation of random copolymer (B1)

A monomer mixture composed of 99 parts by weight of n-butylacrylate (BA) and 1.0 part by weight of hydroxybutyl acrylate was added to a 1 L reactor equipped with a cooling device to facilitate regulating the temperature of the nitrogen gas, . Thereafter, 150 parts by weight of ethylacetate (EAc) was added as a solvent. Nitrogen gas was purged for about 60 minutes and then 0.03 part by weight of AIBN (azobisisobutyronitrile) as a reaction initiator was added thereto while maintaining the temperature at 60 DEG C, and the mixture was reacted for about 8 hours to obtain a random copolymer (B3 ). The produced random copolymer (B1) had a weight average molecular weight of 1,200,000 and a molecular weight distribution of 5.1.

Manufacturing example  7. Preparation of random copolymer (B2)

79.2 parts by weight of n-butylacrylate (BA), 0.8 parts by weight of hydroxybutyl acrylate, and 0.1 part by weight of styrene having a vinyl group at the terminal thereof were placed in a 1 L reactor equipped with a cooling device for nitrogen gas flow- (Glass transition temperature of the homopolymer was 100 占 폚). Thereafter, 150 parts by weight of ethylacetate (EAc) was added as a solvent. Nitrogen gas was purged for about 60 minutes and then 0.03 part by weight of AIBN (azobisisobutyronitrile) as a reaction initiator was added thereto while maintaining the temperature at 60 DEG C, and the mixture was reacted for about 48 hours to obtain a random copolymer (B2 ). The produced random copolymer (B2) had a weight average molecular weight of 130,000 and a molecular weight distribution of 2.5.

Example  One.

Preparation of Coating Liquid (Adhesive Composition)

0.07 parts by weight of a TDI cross-linking agent (Coronate L, manufactured by NPU, Japan), 0.1 part by weight of DBTDL (Dibutyltin dilaurate), 100 parts by weight of a silane coupling agent 1 having an isocyanate And 0.2 part by weight of a silane coupling agent having a beta-cyanoacetyl group were mixed, and ethyl acetate was mixed as a solvent to adjust the coating solid content to about 30% by weight to prepare a coating solution (pressure-sensitive adhesive composition).

Production of adhesive polarizer

The prepared coating solution was coated on a release treated surface of poly (ethylene terephthalate) (MRF-38, manufactured by Mitsubishi) having a thickness of 38 mu m so as to have a thickness of about 23 mu m after drying, Respectively. After drying, a coating layer formed on the releasing PET was laminated on one side of a polarizing plate (COP / PVA / COP laminated structure: COP = cyclo polyolefin, PVA = polyvinyl alcohol polarizing film) to prepare a pressure-sensitive polarizing plate.

Example  2 to 4 and Comparative Example  1 to 6

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

The evaluation results of physical properties of the examples and comparative examples are shown in Table 3 below.

Claims (19)

A first block having a glass transition temperature of 50 DEG C or higher and a second block having a glass transition temperature of -10 DEG C or lower; And a silane coupling agent,
Wherein the silane coupling agent comprises at least two silane coupling agents having different functional groups. The adhesive composition according to claim 1, wherein the silane coupling agent comprises a first silane coupling agent (A) having an isocyanate group and a second silane coupling agent (B) having a functional group other than an isocyanate group. The adhesive composition according to claim 2, wherein the second silane coupling agent (B) comprises any one of an epoxy group, a thiol group, an amino group, a vinyl group, an epoxy group, a beta-cyano group, an acetoacetyl group or a halogen element. The adhesive composition according to claim 3, wherein the content ratio (A / B) of the first coupling agent (A) and the second silane coupling agent (B) is 2 to 30. The adhesive composition according to claim 2, wherein the first silane coupling agent (A) and the second silane coupling agent (B) are contained in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the block copolymer. 3. The adhesive composition according to claim 2, wherein the first silane coupling agent (A)
[Chemical Formula 1]

In Formula 1, R ₁ to R ₃ each independently represent a hydroxyl group, an alkoxy group having 1 to 20 carbon atoms, or an alkyl group having 1 to 20 carbon atoms, and at least one of R ₁ to R ₃ is a group having 1 to 20 carbon atoms Alkoxy group, A is an alkylene group, and R &lt; ₄ &gt; is an isocyanate group. The adhesive composition of claim 1, wherein the block copolymer comprises 5 to 50 parts by weight of the first block and 50 to 95 parts by weight of the second block. The adhesive composition according to claim 1, wherein the first block comprises a polymerization unit derived from a (meth) acrylic acid ester monomer. The adhesive composition of claim 1, wherein the second block comprises a crosslinkable functional group. The adhesive composition according to claim 1, wherein the second block comprises a polymerization unit derived from 80 to 99.9 parts by weight of a (meth) acrylic acid ester monomer and 0.1 to 20 parts by weight of a monomer having a crosslinkable functional group. 11. The adhesive composition according to any one of claims 9 to 10, wherein the crosslinkable functional group is a hydroxyl group, a carboxyl group, an epoxy group, an isocyanate group or a nitrogen-containing functional group. The adhesive composition of claim 1, wherein the first block has a number average molecular weight (Mn) of 2,500 to 150,000. The adhesive composition according to claim 12, wherein the block copolymer has a number average molecular weight (Mn) of 50,000 to 300,000. 14. The adhesive composition according to claim 13, wherein the block copolymer has a molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of 1.0 to 2.5. The adhesive composition according to claim 1, wherein the block copolymer is a diblock copolymer composed of the first block and the second block. The pressure-sensitive adhesive composition according to claim 1, wherein the multifunctional crosslinking agent is contained in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the block copolymer. An adhesive optical laminate having an optical film and a pressure-sensitive adhesive layer provided on at least one side of the optical film and comprising the pressure-sensitive adhesive composition according to claim 1. A pressure-sensitive adhesive polarizing plate having a polarizing plate and a pressure-sensitive adhesive layer provided on at least one side of the polarizing plate and comprising the pressure-sensitive adhesive composition according to claim 1. 18. A display device comprising: a liquid crystal panel; and an adhesive optical laminate according to claim 17 provided on at least one side of the liquid crystal panel or the adhesive polarizer plate according to claim 18.