KR20200129316A - presuure-sensitive adhesive composition, protective film, optical laminate and display device - Google Patents

Abstract

The present application relates to an adhesive composition, and specifically, to an adhesive composition, a protective film containing a cured product thereof, an optical laminate, and a display device. The adhesive composition provides excellent durability.

Description

Adhesive composition, protective film, optical laminate, and display device TECHNICAL FIELD

The present application relates to an adhesive composition. Specifically, it relates to the pressure-sensitive adhesive composition and a protective film containing the cured product, an optical laminate, and a display device.

A liquid crystal display device (hereinafter, "LCD device") typically includes a liquid crystal panel and an optical film including a liquid crystal component injected between two transparent substrates. Examples of the optical film include a polarizing film, a retardation film, or a brightness improving film. A pressure-sensitive adhesive for an optical film may be used to laminate these optical films to each other or to attach the optical film to an adherend such as a liquid crystal panel. For example, a pressure-sensitive adhesive using an acrylic polymer, rubber, urethane resin, silicone resin or ethylene vinyl acetate (EVA) resin may be used. Among the optical films, especially as a pressure-sensitive adhesive for a polarizing plate, a pressure-sensitive adhesive containing an acrylic copolymer having excellent transparency and good resistance to oxidation or yellowing is mainly used.

In the case of a general LCD device or a polarizing plate including the same, which is applied to devices that do not have a large temperature change in the environment, such as a TV, smartphone, or tablet PC, the driving temperature is determined by the heat generated by the backlight unit. It is at the level of 60 to 80° C., and about 95° C. or less is generally considered even when overheating due to use is considered. However, in the case of an LCD device used in a vehicle display or a polarizing plate used therein, the driving temperature may exceed 80 °C and reach 100 °C or more, and further to 150 °C, due to a rapid increase in the temperature inside the vehicle during hot weather. .

The demand for vehicle display devices is increasing. As described above, the pressure-sensitive adhesive applied to the vehicle display may be exposed to a more severe environment (eg, hot weather) than the conventional pressure-sensitive adhesive for optical films, so it is necessary to have excellent vibration resistance, moisture/heat resistance and durability even under severe environments. .

One object of the present application is to provide an adhesive composition having excellent durability even under severe conditions.

Another object of the present application is to provide a protective film, an optical laminate, and a display device having a pressure-sensitive adhesive (layer) formed from the pressure-sensitive adhesive composition.

Another object of the present application is to provide a pressure-sensitive adhesive having excellent vibration resistance, moisture/heat resistance, and optical compensation performance even under severe conditions.

Another object of the present application is to provide an optical laminate and a display device that can be used in a vehicle whose driving temperature is greatly increased during hot weather.

All of the above and other objects of the present application can be solved by the present application described in detail below.

In one example related to the present application, the present application relates to a pressure-sensitive adhesive composition. Specifically, the pressure-sensitive adhesive composition of the present application may be used to form a pressure-sensitive adhesive that provides excellent durability reliability to a vehicle member (eg, LCD or polarizing plate) even under severe conditions such as hot weather.

In the present application, the term "severe condition" means including a "high temperature condition" in which the temperature increases significantly more than usual, such as during a hot weather, so that an excessive load may be applied to the vehicle member to which the adhesive is applied. "High temperature" may mean a temperature greater than about 80 °C. Specifically, the severe condition may mean a condition including a temperature of 100°C or higher, 105°C or higher, 110°C or higher, 115°C or higher, or 120°C or higher. The upper limit of the temperature included in the harsh conditions is not particularly limited, but considering the use of the adhesive, for example, 180°C or less, 170°C or less, 160°C or less, 150°C or less, 140°C or less, 130°C or less, or It may mean a temperature of 125 ℃ or less.

In one example, the "severe condition" is a condition in which'high temperature' as described above is premised, for example, under a high temperature in the above range, a low humidity condition in which the relative humidity is 50% or less or a high humidity condition in which the relative humidity exceeds 50%. Can mean Although not particularly limited, the low humidity condition may have a relative humidity of 45% or less, 40% or less, or 35% or less at the high temperature described above, and the high humidity condition is a relative humidity of 55% or more at the high temperature described above, specifically 60 % Or more, 70% or more, 80% or more, 90% or more, or 100% or more.

In another example, the "harsh condition" may mean a state in which high temperature and room temperature are repeated. In this case, the room temperature is a state that is not particularly reduced or heated, and may be, for example, a temperature in the range of 18 to 35°C.

In another example, the “harsh condition” may mean a state in which “high temperature/high humidity, room temperature, and low humidity conditions” are repeated.

The pressure-sensitive adhesive composition of the present application is configured to have at least two crosslinked structures simultaneously in a cured state. Specifically, in addition to the block copolymer capable of forming the first crosslinked structure by the crosslinkable functional group, the pressure-sensitive adhesive composition has a separate crosslinked structure, that is, a second crosslinked structure distinguished from the first crosslinked structure formed by the block copolymer. It may further include a polyfunctional (meth) acrylate that can form a structure.

In the present application, the term "curing" may mean a process in which at least two components included in the pressure-sensitive adhesive composition chemically react with each other by irradiation and/or heating of electromagnetic waves. In the range of the term ``electromagnetic wave'' in the above, microwaves, infrared (IR), ultraviolet (UV), X-rays and gamma rays, as well as alpha-particle beams, proton beams, Particle beams such as a neutron beam and an electron beam may be included.

In the present application, the term "block copolymer" may refer to a copolymer including blocks of different polymerized monomers.

In one example, the two or more crosslinked structures may not be connected to each other by chemical bonds. For example, apart from the crosslinking reaction of the block copolymer and the crosslinking agent described below, a crosslinking structure by a crosslinking reaction such as polyfunctional (meth)acrylate may be implemented. These two or more crosslinked structures may exist in a state of penetrating each other, an entangled state, or a state connected to each other by a physical bond. This crosslinked structure may be referred to as a so-called interpenetrating polymer network (IPN).

In order to obtain a sufficient optical compensation effect even under severe conditions, it is necessary to align the aromatic groups. For example, the aromatic ring attached to the branch portion of the aromatic group-containing (meth)acrylate described below exists in a random direction due to the entanglement of the polymer chain, but the polymer chain does not straighten when subjected to stress in the adhesive. As a result, aromatic rings can be arranged (aligned) in a domino-like shape. However, in the broll copolymer, due to the high molecular weight of the polymer chain at the level of several hundred thousand, the interchain entanglement is severe and the interchain attraction is also strong, so that the aromatic groups contained in the block copolymer are not easily aligned due to external stress. That is, in the case of using the block copolymer, there is a problem that the alignment of aromatic groups and other optical compensation effects are less than expected. The invention of the present application was invented in this respect.

The block copolymer includes 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 less. In the present application, the "glass transition temperature of a block" constituting the block copolymer is a glass transition temperature of a polymer formed only of monomers included in the block, and may be calculated according to the method described in the following examples.

In one example, the glass transition temperature of the first block may be 50°C or higher, 60°C or higher, 70°C or higher, 75°C or higher, 80°C or higher, 85°C or higher, 90°C or higher, or 95°C or higher. The upper limit of the first block glass transition temperature is not particularly limited, but may be, for example, 150°C or less, 140°C or less, 130°C or less, 120°C or less, 110°C or less, or 100°C or less. In the present application, the first block having a relatively high glass transition temperature may form a hard segment having relatively rigid physical properties in the block copolymer. The first block may exist in a glass form at room temperature, and may serve to impart a cohesive force to an adhesive including the block copolymer.

In one example, the glass transition temperature of the second block may be -10°C or less, -20°C or less, -30°C or less, -35°C or less, or -40°C or less. The lower limit of the second block glass transition temperature is not particularly limited, but may be, for example, -80°C or higher, -70°C or higher, -60°C, -55°C or higher, or -50°C or higher. The second block having a relatively low glass transition temperature may form a soft segment having soft physical properties in the block copolymer. The second block may have molecular flow at room temperature, and may serve to impart stress relaxation properties to the pressure-sensitive adhesive including the block copolymer.

The copolymer including both blocks satisfying the glass transition temperature range may form a fine phase-separated structure in the adhesive. Since the block copolymer exhibits adequate cohesive force and stress relaxation properties according to temperature changes, it forms a pressure-sensitive adhesive that maintains excellent physical properties required for optical films such as interfacial adhesion, high temperature durability reliability, light leakage prevention properties, and reworkability. can do.

In one example, the block copolymer of the present application including the two blocks may be a diblock copolymer or a triblock copolymer. In consideration of the interfacial adhesion of the pressure-sensitive adhesive, high temperature durability reliability, stress relaxation property and reworkability, a diblock copolymer may be advantageous.

As long as blocks having a glass transition temperature in the above range can be formed, the type or content of the monomers for forming each block is not particularly limited.

In one example, the first block and the second block may include a polymerization unit derived from a (meth)acrylic acid ester. In the present application, the term "polymerization unit" may mean a state in which the predetermined monomer is polymerized and contained in a resin, a polymer, or a main chain or side chain of a polymerization reactant formed by polymerization of a predetermined monomer.

As the (meth)acrylic acid ester used for forming the first block, for example, alkyl (meth) acrylate may be used. In consideration of cohesion, glass transition temperature, and adhesion control, an alkyl (meth)acrylate having 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 may be used. have. Examples of such monomers include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate )Acrylate, sec-butyl (meth)acrylate, pentyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-ethylbutyl (meth)acrylate, n-octyl (meth)acrylate, iso Bornyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate and lauryl (meth) acrylate, etc., and one or more of the above has the glass transition temperature You can choose and use it as much as possible.

In one example, as a monomer forming the first block in consideration of the ease of controlling the glass transition temperature, etc., among the monomers, a methacrylic acid ester monomer, for example, 1 to 20 carbon atoms, 1 to 16 carbon atoms, and 1 carbon number Alkyl methacrylate having an alkyl group having 1 to 12 carbon atoms or 1 to 4 carbon atoms may be used.

In one example, the first block may include only a polymerization unit of a (meth)acrylic acid ester, specifically an alkyl (meth)acrylate, and more specifically an alkyl methacrylate.

In one example, the first block is an alkyl (meth)acrylate, a polymerization unit derived from an alkyl methacrylate having an alkyl group having 1 to 3 carbon atoms and a polymerization unit derived from an alkyl methacrylate having an alkyl group having 4 or more carbon atoms. Can include. In the case of having the above configuration, it may be advantageous in improving the high temperature durability of the pressure-sensitive adhesive. Specifically, since the alkyl (meth)acrylate having an alkyl group having 1 to 3 carbon atoms can cause chain entanglement more easily than an alkyl (meth)acrylate having 4 or more carbon atoms of the alkyl group, physical entanglement can occur instead of chemical crosslinking. Crosslinking can be sufficiently imparted to the adhesive resin, thereby providing an adhesive layer excellent in high temperature durability. In this case, the first block includes a polymerization unit derived from 70 to 95 parts by weight of an alkyl methacrylate having an alkyl group having 1 to 3 carbon atoms and a polymerization unit derived from 5 to 30 parts by weight of an alkyl methacrylate having an alkyl group having 4 or more carbon atoms. can do. Although not particularly limited, when forming the first block within the above range, 75 parts by weight or more, 80 parts by weight or more, or 85 parts by weight or more of an alkyl methacrylate having an alkyl group having 1 to 3 carbon atoms may be used, and 4 or more carbon atoms may be used. The alkyl methacrylate having an alkyl group may be used in an amount of 25 parts by weight or less, 20 parts by weight or less, or 15 parts by weight or less.

In one example, unlike the second block described below, the first block may not include a polymerization unit derived from a copolymerizable monomer having a crosslinkable functional group.

In one example, as the (meth)acrylic acid ester used for forming the second block, for example, as in the first block, 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to carbon atoms Alkyl (meta) acrylate having an alkyl group of 8 or 1 to 4 carbon atoms can be used.

In the present application, the second block may include a crosslinkable functional group that reacts with a crosslinking agent described below to form a crosslinked structure of the pressure-sensitive adhesive. When the crosslinkable functional group is included in the second block, it exhibits appropriate cohesive force and stress relaxation properties according to temperature changes to form a pressure-sensitive adhesive that maintains excellent physical properties such as interfacial adhesion, high temperature durability reliability, light leakage prevention properties, and reworkability. can do.

In one example, the second block may include a polymerization unit derived from 60 to 99.9 parts by weight of a methacrylic acid ester monomer and 0.1 to 40 parts by weight of a copolymerizable monomer having a crosslinkable functional group. Specifically, the copolymerizable monomer having a crosslinkable functional group is used in an amount of 35 parts by weight or less, 30 parts by weight or less, 25 parts by weight or less, 20 parts by weight or less, 15 parts by weight or less, 10 parts by weight or less, or 5 parts by weight or less. I can. More specifically, the copolymerizable monomer having a crosslinkable functional group may be used in an amount of 5 parts by weight or less, 4 parts by weight or less, 3 parts by weight or less, 2 parts by weight or less, or 1.5 parts by weight or less. The lower limit may be, for example, 0.2 parts by weight or more, 0.3 parts by weight or more, 0.4 parts by weight or more, or 0.5 parts by weight or more.

In one example, the (meth)acrylic acid ester used to form the second block may be an alkyl acrylate.

The kind of crosslinkable functional group is not specifically limited. For example, it may be a carboxyl group, a sulfonic acid group, a phosphate group, or a hydroxy group.

In one example, the block copolymer may have a crosslinkable functional group excluding an acidic functional group. More specifically, the second block may include a polymerization unit derived from a compound having a crosslinkable functional group excluding an acidic functional group such as a carboxyl group, a sulfonic acid group, or a phosphoric acid group. This is because when the monomer containing the acidic functional group is used, an electrode such as ITO may be corroded.

In one example, the crosslinkable functional group may be a hydroxy group (-OH). For example, the second block may include a polymerization unit derived from a hydroxy group-containing alkyl (meth)acrylate monomer. Alternatively, for example, the second block may include a polymerization unit derived from a hydroxy group-containing alkyl acrylate monomer.

In one example, the second block may include a hydroxy group (-OH) and may have a polymerization unit derived from a copolymerizable monomer represented by Formula 1 below.

[Formula 1]

However, in Formula 1, Q is hydrogen or an alkyl group, A and B are each independently an alkylene group or an alkylidene group, and n is an integer within the range of 0 to 10. In addition, when there are two or more [-O-B-] units in Formula 1, the number of carbon atoms of B in each [-O-B-] unit may be the same or different.

In the present specification, the term ``alkyl group'' is a linear, branched or cyclic 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 unless otherwise specified. It may mean, and the alkyl group may be optionally substituted with one or more substituents. As the alkyl group in Formula 1, a straight or branched alkyl group having 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms may be exemplified. Although not particularly limited, when Q in Formula 1 is an alkyl group, Q may be an alkyl group having 1 to 4 carbon atoms.

In the present specification, the term "alkylene group" or "alkylidene group" is a straight chain 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 unless otherwise specified. , It may mean a branched or cyclic alkylene group or an alkylidene group, and the above may be optionally substituted by one or more substituents. Although not particularly limited, in Formula 1, for example, A and B may each independently be a linear alkylene group having 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms.

In addition, n in Formula 1 may be, for example, 0 to 7, 0 to 5, 0 to 3, or 0 to 2.

Examples of the compound of Formula 1 include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 6-hydroxyhexyl (meth)acrylate. ) Acrylate or hydroxy alkyl (meth) acrylate such as 8-hydroxyoctyl (meth) acrylate, and the like may be used. Or, hydroxyalkylene glycol (meth)acrylate such as 2-hydroxyethylene glycol (meth)acrylate or 2-hydroxypropylene glycol (meth)acrylate may be exemplified as a compound of Formula 1, but the compounds listed above It is not particularly limited to these.

In one example, in consideration of the reactivity of the monomer or the ease of controlling the glass transition temperature, the compound represented by Formula 1 may be hydroxyalkyl acrylate or hydroxyalkylene glycol acrylate.

In one example, the second block may include only a polymerization unit derived from a methacrylic acid ester monomer and a copolymerizable monomer having a crosslinkable functional group.

In one example, the second block may include only a polymerization unit of a (meth)acrylic acid ester, specifically an alkyl (meth)acrylate, and more specifically an alkyl acrylate.

In one example, the first block may include a polymerization unit derived from an alkyl methacrylate, and the second block may include a polymerization unit derived from an alkyl acrylate. The first block including the alkyl methacrylate has a high glass transition temperature and is advantageous for securing durability, and the second block including the alkyl acrylate has a low glass transition temperature, so it may be advantageous to implement adhesive performance.

The first block and/or the second block may further include a polymerization unit derived from any other comonomer, if necessary, for example, for control of a glass transition temperature. Such optional comonomers include (meth)acrylonitrile, (meth)acrylamide, N-methyl (meth)acrylamide, N-butoxy methyl (meth)acrylamide, N-vinyl pyrrolidone or N- Nitrogen-containing monomers such as vinyl caprolactam; Alkoxy alkylene glycol (meth)acrylic acid ester, alkoxy dialkylene glycol (meth)acrylic acid ester, alkoxy trialkylene glycol (meth)acrylic acid ester, alkoxy tetraalkylene glycol (meth)acrylic acid ester, alkoxy polyethylene glycol (meth)acrylic acid Ester, phenoxy alkylene glycol (meth) acrylic acid ester, phenoxy dialkylene glycol (meth) acrylic acid ester, phenoxy trialkylene glycol (meth) acrylic acid ester, phenoxy tetraalkylene glycol (meth) acrylic acid ester or phenoxy Alkylene oxide group-containing monomers such as polyalkylene glycol (meth)acrylic acid ester; Styrene-based monomers such as styrene or methyl styrene; Glycidyl group-containing monomers such as glycidyl (meth)acrylate; Or a carboxylic acid vinyl ester such as vinyl acetate, but is not limited thereto. These comonomers may be used in an amount of, for example, 20 parts by weight or less, 15 parts by weight or less, 10 parts by weight or less, 5 parts by weight or less, or 1 part by weight or less based on the total weight of the block in each block. When any comonomer is included, the lower limit of its content may be, for example, 0.1 parts by weight.

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 a polymer prepared by polymerizing only the monomers forming the first block. The number average molecular weight referred to in the present application can be measured according to the method presented in the following experimental examples using, for example, GPC (Gel Permeation Chromatograph). More specifically, the number average molecular weight (Mn) of the first block may be, for example, the lower limit of 10,000 or more, 15,000 or more, 20,000 or more, 25,000 or more, 30,000 or more, 35,000 or more, 40,000 or more, 45,000 or more, or 50,000 or more. have. And the upper limit may be 140,000 or less, 130,000 or less, 120,000 or less, 110,000 or less, 100,000 or less, 90,000 or less, 80,000 or less, 70,000 or less, 60,000 or less, or 50,000 or less.

In another example, the ratio of the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the first block (Mw/Mn), that is, the molecular weight distribution (PDI=Mw/Mn) may be in the range of 1.0 to 3.0. . More specifically, the lower limit of the PDI value of the first block may be 1.00 or more, 1.05 or more, 1.15 or more, 1.20 or more, 1.25 or more, 1.30 or more, 1.35 or more, 1.40 or more, or 1.45 or more. And the upper limit may be 2.5 or less or 2.0 or less, and more specifically 1.95 or less, 1.90 or less, 1.85 or less, 1.80 or less, 1.75 or less, 1.70 or less, 1.65 or less, 1.60 or less, 1.55 or less, or 1.50 or less.

In one example, the block copolymer may have a number average molecular weight (Mn) of 300,000 or less. More specifically, the number average molecular weight (Mn) of the block copolymer is, for example, its lower limit is 50,000 or more, specifically 55,000 or more, 60,000 or more, 65,000 or more, 70,000 or more, 75,000 or more, 80,000 or more, 85,000 or more, It may be 90,000 or more, 95,000 or more, 100,000 or more, 105,000 or more, 110,000 or more, 115,000 or more, 120,000 or more, 125,000 or more, 130,000 or more, 135,000 or more, 140,000 or more, or 145,000 or more. And the upper limit may be, for example, 250,000 or less, more specifically 200,000 or less, 195,000 or less, 190,000 or less, 185,000 or less, 180,000 or less, 175,000 or less, 170,000 or less, 165,000 or less, 160,000 or less, 155,000 or less, or 150,000 or less. .

In another example, the molecular weight distribution (PDI=Mw/Mn) of the block copolymer may range from 1.0 to 4.0. More specifically, the lower limit of the molecular weight distribution of the block copolymer may be, for example, 1.5 or more, 2.0 or more, or 2.5 or more. More specifically, the lower limit may be 2.55 or more, 2.60 or more, 2.65 or more, 2.70 or more, 2.75 or more, 2.80 or more, 2.85 or more, 2.90 or more, 2.95 or more, 3.00 or more, 3.05 or more, or 3.10 or more. And, the upper limit is, for example, 3.9 or less, 3.8 or less, 3.7 or less, 3.6 or less, 3.5 or less, more specifically 3.45 or less, 3.40 or less, 3.35 or less, 3.30 or less, 3.25 or less, 3.20 or less, 3.15 or less, or 3.10 or less. I can.

As described above, when the molecular weight characteristics of the block copolymer are adjusted, a pressure-sensitive adhesive that maintains excellent physical properties required for an optical film such as interfacial adhesion, high temperature durability reliability, light leakage prevention property, and reworkability can be formed.

In one example, the block polymer of the present application may include 5 parts by weight to 50 parts by weight of the first block and 50 parts by weight to 95 parts by weight of the second block.

In another example, the block copolymer may contain a relatively excessive amount of the second block. Specifically, the block copolymer comprises 55 parts by weight or more, 60 parts by weight or more, 65 parts by weight or more, 70 parts by weight or more, 75 parts by weight or more, 80 parts by weight or more, 85 parts by weight of the second block among the total block copolymers. It can include more than one. The upper limit of the content of the second block in the total block copolymer may be, for example, 90 parts by weight or less, 85 parts by weight or less, 80 parts by weight or less, or 75 parts by weight or less. Further, in this case, the content of the first block is, for example, 45 parts by weight or less, 40 parts by weight or less, 35 parts by weight or less, 30 parts by weight or less, 25 parts by weight or less, 20 parts by weight of the total block copolymer. It may be less than or equal to 15 parts by weight, and its lower limit may be, for example, 10 parts by weight or more, 15 parts by weight or more, 20 parts by weight or more, or 25 parts by weight or more.

A method of preparing the block copolymer is not particularly limited, and a known method may be used. For example, the block polymer may be polymerized in a LRP (Living Radical Polymerization) method. Specifically, an anionic polymerization method 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 an alkali metal or alkaline earth metal salt, or an organic alkali metal compound is polymerized. Anionic polymerization method that is used as an initiator and synthesized in the presence of an organic aluminum compound, atomic transfer radical polymerization method (ATRP) using an atom transfer radical polymerization agent as a polymerization control agent, and an atom transfer radical polymerization agent as a polymerization control agent. ARGET (Activators Regenerated by Electron Transfer) atom transfer radical polymerization (ATRP), ICAR (Initiators for continuous activator regeneration) atom transfer radical polymerization (ATRP), reversible addition of inorganic reducing agents- Polymerization by reversible addition-cleavage chain transfer using a cleavage chain transfer agent (RAFT), or a method using an organic tellurium compound as an initiator may be used, and an appropriate method is selected from the above methods to prepare the block copolymer. I can.

In one example, the pressure-sensitive adhesive composition may further include a crosslinking agent capable of forming a first crosslinked structure by crosslinking reaction with the block copolymer. The crosslinking agent may be a compound having at least two or more functional groups capable of reacting with a crosslinkable group included in the block copolymer, that is, a multifunctional crosslinking agent. As such a crosslinking agent, a crosslinking agent capable of undergoing a crosslinking reaction by application of heat or light may be used. Specifically, an isocyanate crosslinking agent, an epoxy crosslinking agent, an aziridine crosslinking agent, or a metal chelate crosslinking agent can be exemplified.

In one example, when the crosslinkable functional group introduced into the block copolymer is a hydroxy group, an isocyanate-based crosslinking agent may be used as the crosslinking agent. Examples of the isocyanate crosslinking agent include diisocyanate compounds such as tolylene diisocyanate, xylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isoborone diisocyanate, tetramethylxylene diisocyanate or naphthalene diisocyanate, Alternatively, a compound obtained by reacting the diisocyanate compound with a polyol may be used, and as the polyol, for example, trimethylol propane may be used.

In one example, the multifunctional crosslinking agent may be included in the composition in an amount of 0.001 parts by weight or more, based on 100 parts by weight of the block copolymer. Specifically, the content of the multifunctional crosslinking agent may be, for example, 0.01 or more, 0.02 or more, 0.03 or more, 0.04 or more, or 0.05 or more, and more specifically, the content of the crosslinking agent is 0.10 or more, 0.15 or more, 0.20 or more, It may be 0.25 or more, 0.30 or more, 0.35 or more, 0.40 or more, 0.45 or more, or 0.50 or more. The upper limit of the content of the multifunctional crosslinking agent is not particularly limited, but may be, for example, 10 parts by weight or less or 5 parts by weight or less, and specifically, 4 parts by weight or less, 3 parts by weight or less, 2 parts by weight or less, or 1 part by weight It may be less than or equal to part. In this range, the gel fraction, cohesion, adhesion, and durability of the pressure-sensitive adhesive can be excellently maintained.

The pressure-sensitive adhesive composition of the present application is configured to form a separate crosslinking network with the block copolymer. That is, as described above, the pressure-sensitive adhesive composition of the present application, after curing, is applied to the crosslinking of the crosslinkable block copolymer. In addition to the first crosslinked structure formed thereby, it may have a second crosslinked structure different from the first crosslinked structure. That is, the pressure-sensitive adhesive of the present application has a system further having a second crosslinked structure formed independently of a polymer crosslinked network formed by the crosslinkable block copolymer and an interpenetrating network thereby. Therefore, even in a situation in which dimensional change of the optical film occurs, such as shrinking of an optical film (eg, a polarizer or a polarizer) under severe conditions, resistance to dimensional deformation can be secured through entanglement between different crosslinked structure networks. As a result, it is possible to minimize heat-resistance and moisture-heat-resistant durability reliability under severe conditions, particularly in the glass substrate.

In this regard, the pressure-sensitive adhesive composition may include a multifunctional compound forming a second crosslinked structure. In the present application, "polyfunctionality" may mean a compound having two or more polymerizable reactive groups. For example, the pressure-sensitive adhesive composition may include a polyfunctional (meta) acrylate having two or more radical polymerizable groups.

If it has two or more polymerizable reactors, the number of functional groups of the polyfunctional (meta) acrylate is not particularly limited. For example, at least one compound selected from bifunctional (meth)acrylate, trifunctional (meth)acrylate, tetrafunctional (meth)acrylate, 5-functional (meth)acrylate, and 6functional (meth)acrylate Can be used.

In addition, the multifunctional (meth)acrylate may include a cyclic structure in a molecule. The number of carbon atoms of the polyfunctional (meth)acrylate is not particularly limited as long as it can form and contain a cyclic structure, but, for example, 3 to 20 carbon atoms, 4 to 16 carbon atoms, 5 to 12 carbon atoms, or 6 to 8 carbon atoms Can be

In the above, the cyclic structure included in the polyfunctional (meth)acrylate is a carbocyclic structure or a heterocyclic structure; Alternatively, any of a monocyclic or polycyclic structure may be used. As the cyclic structure, a cycloalkyl cyclic structure having 3 to 12 carbon atoms or 3 to 8 carbon atoms, such as cyclopentane, cyclohexane or cycloheptane, etc., may be exemplified, and the cyclic structure is a polyfunctional (meth)acrylate One or more, 1 to 5, or 1 to 3 may be included within. In addition, one or more heteroatoms such as O, S or N may be included in the cyclic structure of the polyfunctional (meth)acrylate. Selection of such an acrylate can be advantageous in controlling the elastic modulus and durability of the pressure-sensitive adhesive.

In one example, the polyfunctional (meth)acrylate is, for example, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentylglycol di(meth)acrylate )Acrylate, polyethylene glycol di (meth) acrylate, neopentylglycol adipate (neopentylglycol adipate) di (meth) acrylate, hydroxyl puivalic acid (hydroxyl puivalic acid) neopentyl glycol di (meth) acrylate, dicyclo Fentanyl (dicyclopentanyl) di(meth)acrylate, caprolactone-modified dicyclopentenyl di(meth)acrylate, ethylene oxide-modified di(meth)acrylate, di(meth)acryloxy ethyl isocyanurate, allyl( allyl)ylated cyclohexyl di(meth)acrylate, tricyclodecanedimethanol(meth)acrylate, dimethylol dicyclopentane di(meth)acrylate, ethylene oxide-modified hexahydrophthalic acid di(meth)acrylate, tri Cyclodecane dimethanol (meth)acrylate, neopentyl glycol modified trimethylpropane di(meth)acrylate, adamantane di(meth)acrylate or 9,9-bis[4-(2-acryloyl) Bifunctional acrylates such as oxyethoxy)phenyl]fluorene; Trimethylolpropane tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, propionic acid-modified dipentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propylene oxide Trifunctional acrylates such as modified trimethylolpropane tri(meth)acrylate, trifunctional urethane (meth)acrylate, or tris(meth)acryloxyethyl isocyanurate; Tetrafunctional acrylates such as diglycerin tetra(meth)acrylate or pentaerythritol tetra(meth)acrylate; 5-functional acrylates, such as propionic acid-modified dipentaerythritol penta (meth)acrylate; And dipentaerythritol hexa(meth)acrylate, caprolactone-modified dipentaerythritol hexa(meth)acrylate or urethane (meth)acrylate (ex. of isocyanate monomer and trimethylolpropane tri(meth)acrylate) Hexafunctional acrylates such as reactants) can be used.

In another example, as the polyfunctional (meth)acrylate, a compound referred to as a so-called photocurable oligomer in the related art, for example, urethane (meth)acrylate, epoxy (meth)acrylate, polyester (Meth)acrylate or polyether (meth)acrylate, and the like may also be used.

The pressure-sensitive adhesive composition may include one or more of the polyfunctional (meth)acrylates listed above, but the types of the polyfunctional compound capable of forming a second crosslinked structure are not limited to those listed above.

In one example, the pressure-sensitive adhesive composition may contain 1 part by weight or more of the multifunctional (meth)acrylate relative to 100 parts by weight of the block copolymer. Specifically, the pressure-sensitive adhesive composition is 2 parts by weight or more, 3 parts by weight or more, 4 parts by weight or more, or 5 parts by weight or more, 6 parts by weight or more, 7 parts by weight or more, 8 parts by weight or more, 9 parts by weight or more, 10 parts by weight It may contain at least 11 parts by weight, at least 12 parts by weight, at least 13 parts by weight, at least 14 parts by weight, or at least 15 parts by weight. In another example, the pressure-sensitive adhesive composition contains 25 parts by weight or less, 24 parts by weight or less, 23 parts by weight or less, 22 parts by weight or less, 21 parts by weight of the polyfunctional (meth)acrylate relative to 100 parts by weight of the block copolymer Parts by weight or less, 20 parts by weight or less, 19 parts by weight or less, 18 parts by weight or less, 17 parts by weight or less, 16 parts by weight or less, 15 parts by weight or less, 14 parts by weight or less, 13 parts by weight or less, 12 parts by weight or less, or 11 parts by weight It may contain less than part. When the polyfunctional (meth)acrylate is included within the above-described range, it is advantageous to form a second crosslinked structure, and even under severe conditions, a pressure-sensitive adhesive having excellent durability, particularly high heat resistance, and excellent light leakage prevention ability may be provided.

In an example related to the present application, the composition may include an aromatic group-containing (meth)acrylate. The aromatic group-containing (meth)acrylate may react with the polyfunctional (meth)acrylate to provide an aromatic group to the second crosslinked structure. As described above, the second crosslinked structure may form an interpenetrating crosslinked structure together with the first crosslinked structure formed by the block copolymer. As a result, compared to a pressure-sensitive adhesive system having only a single crosslinked structure, it is possible to secure more excellent durability under severe conditions including high temperatures. In addition, in the present application, since aromatic groups are included in the second crosslinked structure formed independently of the first crosslinked structure by the block copolymer and the interpenetrating network formed therefrom, the aromatic ring alignment according to the use of the block copolymer as described above. Without interference, it is possible to implement the optical compensation effect. As a result, it is possible to effectively suppress an increase in the light leakage phenomenon under severe conditions.

In one example, the aromatic group-containing (meth)acrylate contained in the composition may be a monofunctional compound. That is, the composition may include an aromatic group-containing monofunctional (meth)acrylate. This is because when a polyfunctional (meth)acrylate is used as an aromatic group-containing compound, molecular motion is restricted, and the optical compensation effect through alignment of the aromatic group may be reduced.

In one example, the pressure-sensitive adhesive may include 5 to 60 parts by weight of the aromatic group-containing (meth)acrylate relative to 100 parts by weight of the multifunctional (meth)acrylate. Specifically, the content of the aromatic group-containing (meth)acrylate is 6 parts by weight or more, 7 parts by weight or more, 8 parts by weight or more, 9 parts by weight or more, 10 parts by weight or more, 11 parts by weight or more, 12 parts by weight or more, 13 parts by weight or more, 14 parts by weight or more, 15 parts by weight or more, 16 parts by weight or more, 17 parts by weight or more, 18 parts by weight or more, 19 parts by weight or more, 20 parts by weight or more, 21 parts by weight or more, 22 parts by weight or more, It may be at least 23 parts by weight, at least 24 parts by weight, or at least 25 parts by weight. More specifically, the content of the aromatic group-containing (meth)acrylate is, for example, 30 parts by weight or more, 31 parts by weight or more, 32 parts by weight or more, 33 parts by weight or more, 34 parts by weight or more, 35 parts by weight or more , 36 parts by weight or more, 37 parts by weight or more, 38 parts by weight or more, 39 parts by weight or more, 40 parts by weight or more, 41 parts by weight or more, 42 parts by weight or more, 43 parts by weight or more, 44 parts by weight or more, or 45 parts by weight or more I can. In addition, in the relationship with the polyfunctional (meth)acrylate, the upper limit of the content of the aromatic group-containing (meth)acrylate is, for example, 59 parts by weight or less, 58 parts by weight or less, 57 parts by weight or less, 56 parts by weight or less Or 55 parts by weight or less. More specifically, the upper limit of the content of the aromatic group-containing (meth)acrylate is, for example, 50 parts by weight or less, 45 parts by weight or less, 40 parts by weight or less, 35 parts by weight or less, 30 parts by weight or less, 25 parts by weight It may be less than or equal to 20 parts by weight or less. It is difficult to expect a sufficient optical compensation effect if too little of the aromatic group-containing (meth)acrylate is contained compared to the polyfunctional (meth)acrylate. In particular, when an aromatic group-containing (meth)acrylate is used less than the above content, the distance between the aromatic rings becomes wide, making it difficult to exert an optical compensation effect. In addition, when it exceeds the above range, since the second crosslinked structure may not be formed densely, the effect of improving the durability of the pressure-sensitive adhesive due to formation in the interpenetrating network may be reduced. This problem is remarkable when using a monofunctional aromatic group-containing (meth)acrylate.

In another example, the pressure-sensitive adhesive composition may include 1 to 30 parts by weight of the polyfunctional (meth)acrylate and the aromatic group-containing (meth)acrylate relative to 100 parts by weight of the block copolymer. Specifically, the total content of the polyfunctional (meth)acrylate and the aromatic group-containing (meth)acrylate, based on 100 parts by weight of the block copolymer, 29 parts by weight or less, 28 parts by weight or less, 27 parts by weight or less, 26 Parts by weight or less, 25 parts by weight or less, 24 parts by weight or less, 23 parts by weight or less, 22 parts by weight or less, 21 parts by weight or less, 20 parts by weight or less, 19 parts by weight or less, 18 parts by weight or less, 17 parts by weight or less, 16 It may be less than or equal to 15 parts by weight, less than 14 parts by weight, less than 13 parts by weight, less than 12 parts by weight, less than 11 parts by weight, or less than 10 parts by weight. And, based on 100 parts by weight of the block copolymer, the lower limit of the total content of the polyfunctional (meth)acrylate and the aromatic group-containing (meth)acrylate is 5 parts by weight or more, 6 parts by weight or more, 7 parts by weight or more , 8 parts by weight or more, 9 parts by weight or more, or 10 parts by weight or more. When the content is less than the above range, that is, when the content of the second crosslinked structure-forming monomer is too small, the interpenetrating network itself may not be formed. In addition, when the content exceeds the above range, the adhesive strength, durability (for example, reduction in stress relaxation effect), and light leakage phenomenon (for example, panel warpage due to reduction in stress relaxation) may all deteriorate as the adhesive becomes too hard. .

The composition may exhibit a sufficient optical compensation effect while containing a small amount of aromatic group-containing (meth)acrylate. For example, the composition may contain 5 parts by weight or less of an aromatic group-containing (meth)acrylate relative to 100 parts by weight of the block copolymer. Specifically, it may include 4.5 parts by weight or less, 4.0 parts by weight or less, 3.5 parts by weight or less, 3.0 parts by weight or less, 2.5 parts by weight or less, 2.0 parts by weight or less, 1.5 parts by weight or less, or 1.0 parts by weight or less.

In the case of containing an aromatic group, the type of the aromatic group-containing (meth)acrylate is not particularly limited. For example, as an aromatic group-containing monofunctional (meth)acrylate, benzyl (meth)acrylate, 2-ethoxy ethyl (meth)acrylate, benzyl (meth)acrylate, or 2-phenoxy ethyl (meth) Acrylate can be used. In addition, one or more of the above compounds may be used.

In one example, the composition may include a polyfunctional methacrylate and a monofunctional aromatic group-containing methacrylate. Alternatively, the composition may include a polyfunctional acrylate and a monofunctional aromatic group-containing acrylate.

In another example, the composition may include a polyfunctional methacrylate and a monofunctional aromatic group-containing acrylate. Alternatively, the composition may include a polyfunctional acrylate and a monofunctional aromatic group-containing methacrylate.

The pressure-sensitive adhesive composition may further include a radical initiator in order to form a second crosslinked structure through a polymerization reaction of a multifunctional (meth)acrylate and the same. As the radical initiator, a radical thermal initiator and/or a radical photoinitiator may be used, and specific types thereof are not particularly limited.

In one example, as the thermal initiator, for example, 2,2-azobis-2,4-dimethylvaleronitrile (V-65, Wako (manufactured by Wako)), 2,2-azobisisobutyronitrile An azo initiator such as (V-60, Wako (manufactured)) or 2,2-azobis-2-methylbutyronitrile (V-59, Wako (manufactured)); Dipropyl peroxydicarbonate (Peroyl NPP, NOF (manufactured)), diisopropyl peroxydicarbonate (Peroyl IPP, NOF (manufactured)), bis-4-butylcyclohexyl peroxydicarbonate (Peroyl TCP, NOF (manufactured) )), diethoxyethyl peroxy dicarbonate (Peroyl EEP, NOF (agent)), diethoxyhexyl peroxy dicarbonate (Peroyl OPP, NOF (agent)), hexyl peroxy dicarbonate (Perhexyl ND, NOF (agent)) ), dimethoxybutyl peroxy dicarbonate (Peroyl MBP, NOF (manufactured)), bis (3-methoxy-3-methoxybutyl) peroxy dicarbonate (Peroyl SOP, NOF (manufactured)), hexyl peroxy pival Rate (Perhexyl PV, NOF (produced)), amyl peroxy pivalate (Luperox 546M75, Atofina (produced)), butyl peroxy pivalate (Perbutyl, NOF (produced)) or trimethylhexanoyl peroxide (Peroyl 355, NOF Peroxyester compounds such as (agent)); Dimethyl hydroxybutyl peroxaneodecanoate (Luperox 610M75, Atofina (manufactured)), amyl peroxy neodecanoate (Luperox 546M75, Atofina (manufactured)) or butyl peroxy neodecanoate (Luperox 10M75, Atofina (manufactured) Peroxy dicarbonate compounds such as agent)); Acyl peroxides such as 3,5,5-trimethylhexanoyl peroxide, lauryl peroxide or dibenzoyl peroxide; Ketone peroxide; Dialkyl peroxide; Peroxy ketal; Alternatively, one or more types of peroxide initiators, such as hydroperoxide, may be used.

In one example, as the photoinitiator, a benzoin-based, hydroxy ketone-based, amino ketone-based, or phosphine oxide-based photoinitiator may be used. Specifically, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylanino acetophenone, 2,2-dimethoxy -2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1one, 1-hydroxycyclohexylphenylketone, 2-methyl- 1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone, 2-aminoanthraquinone, 2-methyl Thioxanthone, 2-ethyl thioxanthone, 2-chloro thioxanthone, 2,4-dimethyl thioxanthone, 2,4-diethyl thioxanthone, benzyl dimethyl ketal, acetophenone dimethyl ketal, p-dimethylamino benzoic acid ester , Oligo[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone] and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide may be exemplified, , But is not limited thereto.

In one example, the radical initiator may be included in an amount of 0.01 parts by weight or more, based on 100 parts by weight of the block copolymer. The content may be changed in consideration of the efficiency of the polymerization reaction of the polyfunctional (meth)acrylate or the ratio of the residual initiator after curing. Specifically, the content of the radical initiator may be 0.05 parts by weight or more, 0.1 parts by weight or more, and more specifically 0.5 parts by weight or more, 1.0 parts by weight or more, 1.5 parts by weight or more, 2.0 parts by weight or more, 2.5 parts by weight or more Alternatively, 3 parts by weight or more may be used. In addition, the upper limit of the content of the radical initiator may be, for example, 20 parts by weight or less, 15 parts by weight or less, 10 parts by weight or less, or 5 parts by weight or less.

In addition, the pressure-sensitive adhesive composition may further include additives such as an antistatic agent, a curing agent, an ultraviolet stabilizer, an antioxidant, a colorant, a reinforcing agent, a filler, an antifoaming agent, a surfactant, or a plasticizer. The specific type or content of the additive is not particularly limited.

In one example, the adhesive composition may further include a silane coupling agent. For example, a silane coupling agent containing 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 may be used.

In one example, the silane coupling agent may be a compound having a beta-cyano group or one or more selected from compounds having an acetoacetyl group. Specifically, the silane coupling agent may be at least one selected from a compound having a beta-cyano group represented by Formula 2 below and a compound having an acetoacetyl group represented by Formula 3 below.

[Formula 2]

(R ₁ ) _n Si(R ₂ ) _(4-n)

[Formula 3]

(R ₃ ) _n Si(R ₂ ) _(4-n)

In Formula 2 or 3, R1 is a beta-cyanoacetyl group or a beta-cyanoacetylalkyl group, R3 is an acetoacetyl group or an acetoacetylalkyl group, R2 is an alkoxy group, and n is a number of 1 to 3.

In 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 such an alkyl group may be linear, branched or cyclic. I can. In addition, in 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 such an alkoxy group may be a linear, branched or ring It can be a prize.

Examples of the compound represented by Formula 2 or 3 include acetoacetylpropyl trimethoxysilane, acetoacetylpropyl triethoxy silane, beta cyanoacetylpropyl trimethoxysilane or beta cyanoacetylpropyl triethoxy silane. However, it is not particularly limited thereto.

In one example, the composition may include 0.01 to 5 parts by weight of the silane coupling agent relative to 100 parts by weight of the block copolymer. Specifically, the lower limit of the content of the silane coupling agent is, for example, 0.02 parts by weight or more, 0.03 parts by weight or more, 0.04 parts by weight or more, 0.05 parts by weight or more, more specifically, 0.1 parts by weight or more, 0.15 parts by weight or more, It may be 0.2 parts by weight or more, 0.3 parts by weight or more, 0.4 parts by weight or more, or 0.5 parts by weight or more. In addition, the upper limit of the content of the silane coupling agent may be, for example, 4 parts by weight or less, 3 parts by weight or less, 2 parts by weight or less, or 1 part by weight or less.

The adhesive composition may further contain a tackifier, if necessary. As the tackifier, for example, a hydrocarbon resin or a hydrogenated product thereof, a rosin resin or a hydrogenated product thereof, a rosin ester resin or a hydrogenated product thereof, a terpene resin or a hydrogenated product thereof, a terpene phenol resin or a hydrogenated product thereof, a polymerized rosin resin or One kind or a mixture of two or more kinds, such as a polymerized rosin ester resin, may be used, but 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 be used to provide an adhesive layer for an optical film. The optical film may be, for example, a polarizing film, a retardation film, an anti-glare film, a wide viewing angle compensation film, or a brightness enhancing film.

In one example, the pressure-sensitive adhesive composition may be a pressure-sensitive adhesive composition for a protective film. The protective film may be used for protecting the surface of various optical films. The protective film may be attached to the optical film through an adhesive layer formed from the adhesive composition of the above configuration. In another example, the pressure-sensitive adhesive composition may be used to laminate two or more films of the optical films listed above.

In another example related to the present application, the present application relates to a protective film. The protective film may include a protective base layer; And a pressure-sensitive adhesive layer positioned on at least one surface of the protective substrate layer and formed by curing the pressure-sensitive adhesive composition of the above configuration. Accordingly, the pressure-sensitive adhesive layer includes an interpenetrating polymer network having a first crosslinked structure and a second crosslinked structure. In addition, an aromatic group is bonded to the second crosslinked structure forming the interpenetrating polymer network.

The protective film may be used to protect the surface of various optical films. At this time, it may be attached to the surface of the optical film through the pressure-sensitive adhesive layer of the protective film.

The kind of the protective base layer is not particularly limited. For example, the protective substrate layer may be a glass substrate, or may be a substrate containing a polymer component. For example, a cellulose-based film such as TAC (Triacetyl cellulose); Polyester-based films such as polycarbonate films or PET (poly(ethylene terephthalet)); Polyethersulfone film; Alternatively, a film having a single or two or more laminated structure, such as a polyethylene film, a polypropylene film, or a polyolefin-based film manufactured using a resin having a cyclo-based or norbornene structure or an ethylene-propylene copolymer, may be used as the protective base layer. .

In another example of the present application, the present application is directed to an optical laminate. An exemplary optical laminate is an optical film; And a pressure-sensitive adhesive layer positioned on at least one surface of the optical film and formed by curing the pressure-sensitive adhesive composition of the above configuration.

In one example, the optical laminate may include a glass substrate and a pressure-sensitive adhesive layer directly positioned on one surface of the glass substrate. In this case, the adhesive layer may be positioned between the optical film and the glass substrate.

The pressure-sensitive adhesive layer included in the optical laminate includes a cured product of the pressure-sensitive adhesive composition of the present application described above. That is, the adhesive composition may be included in the adhesive layer while implementing a crosslinked structure, and accordingly, the adhesive layer includes an interpenetrating polymer network having a first crosslinked structure and a second crosslinked structure. An aromatic group is bonded to the second crosslinked structure forming the interpenetrating polymer network.

In one example, the glass substrate may be included in the optical film. For example, when the optical film is a polarizing plate, the glass substrate may be a kind of protective film to protect the polarizer, and the adhesive layer is used to attach the polarizer and the glass substrate, or the side opposite the glass substrate where the glass substrate and the polarizer contact It can be placed on top and used to bond other members to the glass substrate.

In another example, the glass substrate may have a configuration separate from the optical film. For example, the glass substrate may be a part of a liquid crystal panel as a component that confines a liquid crystal layer, and in this case, the adhesive layer may be used to attach a polarizing plate and a liquid crystal panel.

In one example, the optical film may be an optical film that can be used in a vehicle display or an optical member. As described above, the vehicle optical film may be placed in more severe conditions than general high temperature and/or high humidity conditions in which an optical film used for a TV, a smart phone, or a tablet PC may be placed. For example, an optical film for a vehicle can be driven under severe conditions such as the driving temperature at which it is used exceeds, for example, 80°C or 100°C.

In one example, as the optical film, a polarizing plate, a polarizer, a retardation film, a brightness enhancing film, an anti-glare film, a wide viewing angle compensation film, etc., or a laminate in which two or more of the above are laminated may be exemplified. In the present application, the terms'polarizer' and'polarizing plate' refer to objects that are distinguished from each other. That is, the polarizer refers to a film, sheet, or device itself exhibiting a polarizing function, and the polarizing plate refers to an optical device including other elements together with the polarizer. Other elements that may be included in the optical element together with the polarizer may include a polarizer protective film or a retardation layer, but are not limited thereto.

In one example, the optical film used for the adhesive-type optical laminate may be a polarizer. That is, the present application relates to an adhesive polarizing plate.

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

The 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 type 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, for example, by gelling a polyvinyl acetate-based resin. In this case, the polyvinyl acetate-based resin that can be used may include not only a homopolymer of vinyl acetate, but also a copolymer of vinyl acetate and other monomers copolymerizable therewith. Examples of the monomers copolymerizable with vinyl acetate may include one or more mixtures of unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids and acrylamides having an ammonium group, but are limited thereto. no. The degree of gelation of the polyvinyl alcohol-based resin may be about 85 mol% to 100 mol%, preferably 98 mol% or more. The polyvinyl alcohol-based resin may be further modified, for example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. In addition, the degree of polymerization of the polyvinyl alcohol-based resin may be generally about 1,000 to 10,000 or about 1,500 to 5,000.

The polarizer is a process of stretching a polyvinyl alcohol-based resin film as described above (ex.uniaxial stretching), a process of dyeing a polyvinyl alcohol-based resin film with a dichroic dye and adsorbing the dichroic dye, and the dichroic dye is adsorbed. The polyvinyl alcohol-based resin film can be prepared through a process of treating the resulting polyvinyl alcohol-based resin film with an aqueous boric acid solution and a process of washing with water after treatment with an aqueous boric acid solution. In the above, as the dichroic dye, iodine or a dichroic organic dye may be used.

In addition to the polarizer, the polarizing plate may include a protective film and/or an optical functional film.

In one example, the polarizing plate may include a protective film attached to one or both surfaces of the polarizer, and in this case, the adhesive layer of the configuration described above may be formed on one or both surfaces of the protective film. The type of the protective film is not particularly limited. For example, the protective film may be a glass substrate, or may be a substrate containing a polymer component. For example, a cellulose-based film such as TAC (Triacetyl cellulose); Polyester-based films such as polycarbonate films or PET (poly(ethylene terephthalet)); Polyethersulfone film; Alternatively, a film having a single or two or more layered structure, such as a polyethylene film, a polypropylene film, or a polyolefin-based film prepared using a resin having a cyclo-based or norbornene structure, or an ethylene-propylene copolymer, may be used as the protective film. The protective film may have two or more stacked structures.

In one example, the polarizing plate may further include one or more optical functional films selected from the group consisting of a reflective film, an anti-glare film, a retardation film, a wide viewing angle compensation film, and a brightness enhancing film. The optical functional film may have two or more stacked structures.

In one example, the polarizing plate may include at least one wide viewing angle compensation film selected from ±A film, ±B film, and ±C film. In the present application,'A film' refers to a film that satisfies the refractive index of the film nx ≠ny = nz. In this case, a case of nx> ny is referred to as a +A film, and a case of nx <ny is referred to as a -A film. . The'B film' refers to a film whose refractive index satisfies nx ≠ny ≠ nz, and a case of nx> ny> nz is referred to as a -B film, and a case of nz> nx> ny is referred to as a +B film. The'C film' refers to a film in which the refractive index of the film satisfies nx = ny ≠nz. In this case, a case of ny <nz is referred to as a +C film, and a case of ny> nz is referred to as a -C film. In this regard, nx means the refractive index in the slow axis direction in the plane direction of the film or plate, ny means the refractive index in the direction perpendicular to the slow axis in the plane direction of the film or plate, and nz is the film Or it means the refractive index in the thickness direction of the plate.

In one example, the polarizing plate may include a retardation film. The retardation layer may be, for example, a quarter wave plate (QWP). The quarter wave plate may have a quarter wave phase delay characteristic. In the present specification, the term n-wavelength phase delay property refers to a property capable of retarding incident light by n times the wavelength of the incident light within at least a partial wavelength range. The quarter-wavelength phase delay characteristic may be a characteristic of converting incident linearly polarized light into elliptical polarized light or circularly polarized light, and conversely converting incident elliptical polarized light or circularly polarized light into linearly polarized light. As the quarter wave plate, a quarter wave plate generally manufactured and distributed in the related art field may be used. For example, a uniaxially stretched cycloolefin film, a uniaxially stretched polyethylene terephthalate film, a uniaxially stretched polycarbonate film, or a liquid crystal film may be used without limitation.

In the present application, the method of forming the pressure-sensitive adhesive layer is not particularly limited, and for example, a method of implementing a crosslinked structure by directly coating and curing the pressure-sensitive adhesive composition on a substrate such as a polarizing plate, or a release treatment of a release film After forming a crosslinked structure by coating and curing the adhesive composition on the surface, a method of transferring it may be used.

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

It is preferable from the viewpoint of performing a uniform coating process that the crosslinking agent included in the pressure-sensitive adhesive composition is controlled so that the crosslinking reaction of the functional group does not proceed. Through this, the crosslinking agent forms a crosslinked structure in the curing and aging process after the coating operation, thereby improving the cohesiveness of the pressure-sensitive adhesive, and improving adhesive properties and cuttability.

In addition, the coating process is preferably carried out after sufficiently removing bubbles-causing components such as volatile components or reaction residues in the pressure-sensitive adhesive composition, and accordingly, the crosslinking density or molecular weight of the pressure-sensitive adhesive is too low, so that the elastic modulus decreases, and Bubbles existing between the glass plate and the adhesive layer become large, thereby preventing a problem of forming a scattering body inside.

After coating, a method of implementing a crosslinked structure by curing the adhesive composition 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 crosslinking agent may be induced.

In another example relating to the present application, the present application also relates 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 pressure-sensitive adhesive described above.

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

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

Examples of the liquid crystal panel in the apparatus include a passive matrix type panel such as a twisted nematic (TN) type, a super twisted nematic (STN) type, a ferroelectic (F) type, or a polymer dispersed (PD) type; An active matrix type panel such as a two terminal type or a three terminal type; Known panels, such as an IPS (In Plane Switching) panel and a vertical alignment (VA) panel, may all be applied.

Other configurations of the display device, for example, the type 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 the art may be employed without limitation.

According to an example of the present application, a pressure-sensitive adhesive composition having excellent vibration resistance, moisture/heat resistance durability, and optical compensation performance even under severe conditions may be provided. The pressure-sensitive adhesive composition may be used in a protective film, an optical laminate, and a display device. The pressure-sensitive adhesive may be used, in particular, for a vehicle member whose driving temperature increases significantly during extreme heat.

Hereinafter, the present application will be described in detail through examples. However, the scope of protection of the present application is not limited by the examples described below.

<Measurement or evaluation items>

1. Molecular weight

The number average molecular weight (Mn) and molecular weight distribution (PDI) of each block or block copolymer were measured using GPC (Gel Permeation Chromatograph), and the GPC measurement conditions are as follows. The measurement results were converted using standard polystyrene (Aglient system (manufactured)) to prepare the calibration curve.

<GPC measurement conditions>

Measuring instrument: Aglient GPC (Aglient 1200 series, U.S.)

Column: Connect 2 PL Mixed B

Column temperature: 40°C

Eluent: THF (Tetrahydrofuran)

Flow rate: 1.0 mL/min

Concentration: ~1mg/mL (100µl injection)

2. Glass transition temperature

The glass transition temperature (T _g ) of each block of the block copolymer or block copolymer was calculated according to Equation A below.

[Equation 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 represents the glass transition temperature when each monomer forms a homopolymer. That is, in Equation A, the right side is the result of summing the calculated values after calculating all of the values (Wn/Tn) by dividing the weight fraction of the monomer used by the glass transition degree indicated when the monomer forms a homopolymer. to be.

3. Durability

The polarizing plates prepared in Examples and Comparative Examples were cut to have a width of about 180 mm and a length of about 320 mm, and attached to a commercial liquid crystal panel of 19 inches. Then, the liquid crystal panel to which the polarizing plate is attached is stored in an autoclave (50° C. 5 atm) for about 20 minutes to prepare a sample. Moist heat resistance was evaluated according to the following criteria after leaving the sample prepared at 65° C. and 95% relative humidity for 500 hours. In addition, heat resistance and durability were evaluated according to the following criteria after maintaining the prepared samples at 95° C. and 105° C. for 500 hours, respectively.

<Evaluation criteria for heat and moist heat resistance>

A: No bubbles and peeling occurred

B: Some bubbles and/or peeling occurred

C: A large amount of bubbles and/or peeling occurs

4. Light transmission Uniformity( Light leak ) evaluation

The polarizing plate to which the pressure-sensitive adhesive composition prepared in Examples and Comparative Examples was attached to one side was cut to a width of about 200 mm and a length of about 200 mm, and 90 degrees on both sides of a sodalime glass having a width of 250 mm and a length of 250 mm. Attached by crossing (degree). Thereafter, the glass substrate to which the polarizing plate was attached was stored in an autoclave (50° C. 5 atm) for about 20 minutes to prepare a sample. The prepared sample was stored in an oven at 95° C. for 72 hours and then mounted on a back light unit at room temperature, and the uniformity of light transmittance was observed and evaluated according to the following criteria.

<Light transmission uniformity evaluation criteria>

A: It is difficult to judge the non-uniformity of light transmittance with the naked eye.

B: There is a slight non-uniformity of light transmission

C: There is some non-uniformity of light transmission

D: There is a large amount of non-uniformity in light transmission

5. Glass adhesion evaluation

The adhesive polarizing plate prepared in Examples or Comparative Examples was cut to have a width of 25 mm and a length of 100 mm. Subsequently, the release PET film adhered to the pressure-sensitive adhesive layer is peeled off, and the pressure-sensitive adhesive polarizing plate is adhered to the soda lime glass using a 2 kg roller according to JIS Z 0237. A sample is prepared by compressing the glass to which the polarizing plate is attached for about 20 minutes in an autoclave (50°C, 5 atm), and storing it in a constant temperature and humidity condition (23°C, 50% relative humidity) for 24 hours. Thereafter, using a TA equipment (Texture Analyzer, manufactured by Stable Micro Systems Co., Ltd.), the polarizing plate was peeled off from the glass at a peeling rate of 0.3 m/min and a peeling angle of 180 degrees, while peeling force (unit: gf/25mm). Measured.

<of the copolymer Manufacturing example >

Manufacturing example 1. Preparation of block copolymer (A1)

EBiB (ethyl 2-bromoisobutyrate) 0.032 g, methyl methacrylate (MMA) 10.8 g, butyl methacrylate (BMA) 1.9 g were mixed with ethyl acetate (EAc) 9.5 g. The reactor containing the mixture was sealed, purged and stirred with nitrogen at about 25° C. for about 30 minutes, and dissolved oxygen was removed through bubbling. Thereafter, 0.002 g of CuBr2, 0.006 g of TPMA (tris(2-pyridylmethyl)amine) and 0.003 g of V-65 (2,2'-azobis(2,4-dimethyl valeronitrile)) were added to the mixture from which oxygen was removed. Then, the reaction was initiated in a reaction tank at about 67°C (polymerization of the first block). When the conversion rate of methyl methacrylate is about 70%, a mixture of 88.0 g of butyl acrylate (BA), 1.12 g of hydroxybutyl acrylate (HBA) and 100 g of ethyl acetate (EAc), previously bubbled with nitrogen It was charged in the presence of nitrogen. Thereafter, 0.004 g of CuBr2, 0.01 g of TPMA and 0.01 g of V-65 were added to the reactor, and a chain extension reaction was performed (polymerization of the second block). When the conversion ratio of the monomer (BA) reached 80% or more, the reaction mixture was exposed to oxygen and diluted in an appropriate solvent to terminate the reaction to prepare a block copolymer (V-65 in the above process is It was appropriately divided and added until the reaction was completed.

Manufacturing example 2. Preparation of block copolymer (A2)

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

[Table 1]

Manufacturing example 3. Preparation of random copolymer (B1)

A mixture of monomers consisting of 99 parts by weight of n-butylacrylate (BA) and 1.0 parts by weight of hydroxybutyl acrylate was added to a reactor equipped with a cooling device so that nitrogen gas was refluxed and temperature control was easy. Then, 200 parts by weight of ethylacetate (EAc) was added as a solvent. After purging nitrogen gas for 60 minutes to remove oxygen, the temperature was maintained at 60°C, and 0.05 parts by weight of azobisisobutyronitrile (AIBN) as a reaction initiator was added and reacted for 8 hours at random. Copolymer (B1) was prepared. The weight average molecular weight was 1.2 million and molecular weight distribution 5.7.

Manufacturing example 4. Preparation of random copolymer (B2)

N-butylacrylate (BA) 93.5 parts by weight, hydroxybutyl acrylate 1.0 parts by weight, 2-phenoxyethyl acrylate in a 1L reactor equipped with a cooling device to allow nitrogen gas to be refluxed and temperature controlled easily (PEA) A mixture of monomers consisting of 5.5 parts by weight was added. Then, 250 parts by weight of ethylacetate (EAc) was added as a solvent. After purging nitrogen gas for 60 minutes to remove oxygen, the temperature was maintained at 60°C, and 0.06 parts by weight of azobisisobutyronitrile (AIBN) as a reaction initiator was added and reacted for 8 hours at random. Copolymer (B2) was prepared. The weight average molecular weight was 1.1 million and molecular weight distribution was 6.3.

< Example And Comparative example >

Example One

Preparation of coating solution (adhesive composition): 0.15 parts by weight of a crosslinking agent (Coronate L, manufactured by NPU Japan), 0.1 parts by weight of DBTDL (Dibutyltin dilaurate), beta cyano based on 100 parts by weight of the block copolymer (A1) prepared in Preparation Example 1 0.2 parts by weight of a silane coupling agent having an acetyl group (M812, manufactured by LG Chem), 1.5 parts by weight of a polymerization initiator (Irg184, manufactured by Ciba Specialty Chemicals, Switzerland), 7 parts by weight of a polyfunctional acrylate (Aronix M-315, manufactured by Dongwoo Corporation), A coating solution (adhesive composition) by mixing 3 parts by weight of PEA (monofunctional, phenoxyethyl acrylate) with an aromatic group-containing (meth)acrylate, and mixing ethyl acetate as a solvent to adjust the coating solid content to about 30% by weight. Was prepared.

Preparation of adhesive polarizing plate: Coating the prepared coating solution on the release-treated surface of 38 μm-thick release PET (poly(ethylene terephthalate)) (MRF-38, manufactured by Mitsubishi) with a release treatment so that the thickness after drying is about 23 μm. And maintained in an oven at 95° C. for about 3 minutes. After drying, a coating layer formed on the release PET was laminated on one side of a polarizing plate (stack structure of COP/PVA/COP: COP=cyclopolyolefin, PVA=polyvinyl alcohol-based polarizing film) to prepare an adhesive polarizing plate.

Example 2 to 3 and Comparative example 1 to 5

When preparing the pressure-sensitive adhesive composition (coating solution), a pressure-sensitive adhesive composition (coating solution) and a pressure-sensitive adhesive polarizing plate were prepared in the same manner as in Example 1, except that each component and ratio were adjusted as shown in Table 2 below.

[Table 2]

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

[Table 3]

From Tables 1 to 3, it can be seen that Examples 1 to 3 have excellent optical properties and durability-related properties.

On the other hand, Comparative Example 1 including the first crosslinked structure and the second crosslinked structure without introducing an aromatic group was excellent only in durability and poor optical properties.

In the case of the copolymer (A2) used in Comparative Example 2, it was designed to contain 4.5 g of PEA per 100 g of the copolymer, and in the case of Example 2, it was designed to contain 4 parts by weight of PEA in the copolymer (A1). That is, in the case of Comparative Example 2, a larger amount of PEA was contained than in Example 2. However, Comparative Example 2, which includes only the block copolymer into which an aromatic group is introduced and a crosslinked structure by the block copolymer, has poor optical properties even though the total amount of the aromatic group-containing monomer is larger than that of the Example, and the interpenetrating polymer network The durability was also degraded because there was no.

In addition, through Comparative Examples 3 to 5, it was confirmed that both durability and optical properties were reduced when using a random copolymer other than a block copolymer. In particular, in the case of Comparative Example 5, in which an interpenetrating network including an aromatic group was formed in the random copolymer, the peeling force was significantly lowered, and as a result, it was not able to properly perform the role of the pressure-sensitive adhesive, and as a result, severe lifting occurred during durability evaluation.

In summary, when an aromatic compound or an aromatic ring derived from the aromatic compound is included on a separate crosslinked network in addition to the crosslinked structure by the copolymer, the aromatic compound in addition to the excellent heat and moist heat resistance provided by the first crosslinked structure by the copolymer The optical compensation effect provided by this can be sufficiently realized even with a smaller amount. In particular, aromatic compounds may hinder the improvement of overall physical properties of the adhesive while lowering the polymerization rate and efficiency during the polymerization process of the polymer. Therefore, the reduction of the aromatic content as described above has significance in exhibiting a sufficient optical compensation effect and preventing degradation of adhesive properties.

Claims (23)

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 less and having a crosslinkable functional group forming a first crosslinked structure. And
A pressure-sensitive adhesive composition comprising a polyfunctional (meth)acrylate forming a second crosslinked structure, and an aromatic group-containing (meth)acrylate reacting with the polyfunctional (meth)acrylate to provide an aromatic group to the second crosslinked structure. The pressure-sensitive adhesive composition according to claim 1, further comprising a radical polymerization initiator. The pressure-sensitive adhesive composition of claim 1, comprising 5 to 60 parts by weight of the aromatic group-containing (meth)acrylate relative to 100 parts by weight of the polyfunctional (meth)acrylate. The pressure-sensitive adhesive composition of claim 1, comprising 1 to 30 parts by weight of the polyfunctional (meth)acrylate and the aromatic group-containing (meth)acrylate relative to 100 parts by weight of the block copolymer. The pressure-sensitive adhesive composition of claim 2, wherein the radical polymerization initiator is contained in an amount of 0.01 to 10 parts by weight, based on 100 parts by weight of the block copolymer. The pressure-sensitive adhesive composition according to claim 1, comprising a polyfunctional acrylate and a monofunctional aromatic group-containing acrylate. The pressure-sensitive 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 pressure-sensitive adhesive composition of claim 1, wherein the first block and the second block contain a polymerized unit derived from a (meth)acrylic acid ester. The pressure-sensitive adhesive composition according to claim 1, wherein the first block contains a polymerized unit derived from alkyl methacrylate. The pressure-sensitive adhesive composition of claim 1, wherein the first block does not have a crosslinkable functional group. The pressure-sensitive adhesive composition of claim 1, wherein the second block comprises a polymerization unit derived from 60 parts by weight to 99.9 parts by weight of an alkyl (meth)acrylate and 0.1 parts by weight to 40 parts by weight of a copolymerizable monomer having a crosslinkable functional group. The pressure-sensitive adhesive composition of claim 11, wherein the second block comprises an alkyl acrylate. The pressure-sensitive adhesive composition of claim 1, wherein the first block has a number average molecular weight in the range of 2,500 to 150,000. The pressure-sensitive adhesive composition of claim 1, wherein the number average molecular weight of the block copolymer is in the range of 50,000 to 300,000. The pressure-sensitive adhesive composition according to claim 1, wherein the block copolymer has a molecular weight distribution [weight average molecular weight (Mw)/number average molecular weight (Mn)] in the range of 1.0 to 4.0. The pressure-sensitive adhesive composition of claim 1, wherein the block copolymer is a diblock copolymer. The pressure-sensitive adhesive composition according to claim 1, further comprising a multifunctional crosslinking agent that reacts with a crosslinkable functional group of the second block to form a first crosslinked structure. The pressure-sensitive adhesive composition of claim 17, wherein the polyfunctional crosslinking agent is included in an amount of 0.001 to 10 parts by weight, based on 100 parts by weight of the block copolymer. The pressure-sensitive adhesive composition of claim 1, further comprising a silane coupling agent. A protective base layer; A protective film comprising a; located on at least one surface of the protective substrate layer, the pressure-sensitive adhesive composition according to claim 1 is cured to have a first cross-linked structure and a second cross-linked structure interpenetrating polymer network. Optical film; And a pressure-sensitive adhesive layer positioned on at least one surface of the optical film and having an interpenetrating polymer network having a first crosslinked structure and a second crosslinked structure by curing the pressure-sensitive adhesive composition according to claim 1. The optical laminate according to claim 21, wherein the optical film is a polarizer. Liquid crystal panel; And an optical laminate according to claim 21 attached to the liquid crystal panel via an adhesive layer.