KR20200025044A - Pressure sensitive adhesive composition, optical laminate and display device - Google Patents

Abstract

The present invention relates to an adhesive composition, and an optical laminate comprising the same. The adhesive composition comprises a polymer unit derived from a monomer having a cross-linkable functional group (a1) and a monomer having a cross-linkable functional group and an aromatic group (a2) in a block having a low glass transition temperature. The adhesive layer comprising the composition suppress side effects due to excessive use of the monomers for introducing the cross-linkable functional groups and the aromatic group, and provides excellent durability even under harsh conditions. In addition, since the adhesive composition does not contain an acidic functional group, the corrosion of a display device can be prevented.

Description

Pressure sensitive adhesive composition, optical laminate and display device

The present application relates to an adhesive composition, an optical laminate and a display device.

Liquid crystal display devices (hereinafter referred to as "LCD devices") generally include a liquid crystal panel and an optical film containing a liquid crystal component injected between two transparent substrates. As an optical film, there exists a polarizing film, retardation film, a brightness improving film, etc., and the adhesive for optical films is used in many cases, in order to laminate | stack such an optical film and to adhere an optical film to adherends, such as a liquid crystal panel. Examples of the pressure-sensitive adhesives include acrylic polymers, rubbers, urethane resins, silicone resins, ethylene vinyl acetate (EVA) resins, and the like. Adhesives for optical films, particularly polarizing plates, are excellent in transparency and resistant to oxidation and yellowing. Adhesives containing this good acrylic copolymer are mainly used.

In the case of a general LCD or a polarizing plate including the same, which is applied to a device in which the temperature change of the environment used is not large, such as a TV, a smartphone, a tablet PC, and the like, the driving temperature is determined by heat generated in the backlight unit, which is about 60 It is at a level of 80 to 80 ° C., and about 95 ° C. or less is common even in consideration of overheating due to use. However, in the case of an LCD or a polarizing plate including the same, which is used in a vehicle display, the driving temperature of the vehicle may significantly exceed 80 ° C. and thus reach 100 ° C. or more and even 150 ° C. due to a sudden increase in the temperature inside the vehicle.

In recent years, demand for vehicle display apparatuses is increasing. As described above, the pressure-sensitive adhesive applied to a vehicle display may be exposed to a more severe environment (for example, a cold weather) than the pressure-sensitive adhesive for an existing optical film, it is necessary to have excellent durability even in the harsh environment. In particular, it is necessary to improve vibration resistance and durability under conditions where the driving temperature of the polarizing plate or LDC greatly exceeds 80 ° C.

One object of the present application is to provide a pressure-sensitive adhesive composition capable of providing excellent durability under heat and / or moisture resistance conditions in which the driving temperature is significantly above 80 ° C.

Another object of the present application is to provide an optical laminate and / or display device having a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition.

Another object of the present application is to provide an optical laminated body and / or display device for a vehicle having a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition, in which the driving temperature is greatly increased.

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

In one example of the present application, the present application relates to an 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 for a vehicle member (eg, an LCD or a polarizing plate) even in harsh conditions such as a cold weather. The harsh conditions in the present application means a temperature condition that can increase the temperature significantly than usual, such as a cold weather to give an excessive load on the vehicle member to which the pressure-sensitive adhesive is applied, for example, may mean a temperature of more than about 80 ℃. have. Specifically, the temperature is at least 100 ° C, at least 105 ° C, at least 110 ° C, at least 115 ° C, or at least 120 ° C, and about 150 ° C or less, 140 ° C or less, 130 ° C or less, or 125 ° C or less. Can be.

The pressure-sensitive adhesive composition of the present application may include a block copolymer. In the present application, the term "block copolymer" may refer to a copolymer including 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 less. In the present application, the "glass transition temperature of the block" constituting the block copolymer is a glass transition temperature of the polymer formed only with the 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 at least 50 ℃, at least 60 ℃, at least 70 ℃, at least 75 ℃, at least 80 ℃ or 85 ℃. 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 properties in the block copolymer. The first block may be present in a glass state at room temperature, and may serve to impart cohesion to the pressure-sensitive adhesive including the block copolymer.

In one example, the glass transition temperature of the second block is -10 ℃ or less, -15 ℃ or less -20 ℃ or less, -25 ℃ or less, -30 ℃ or less, -35 ℃ or less, -40 ℃ or less, -45 Or less than or equal to -50 ° C. The lower limit of the second block glass transition temperature is not particularly limited, but for example, -90 ° C or higher, -85 ° C or higher, -80 ° C or higher, -75 ° C or higher, -70 ° C or higher, -65 ° C or higher, or- It may be at least 60 ℃. 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 flowability at room temperature, and may play a role of providing stress relaxation property 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 separation structure in the pressure-sensitive adhesive. Since the block copolymer exhibits appropriate cohesion and stress relaxation property with temperature change, it forms an adhesive that maintains excellent physical properties required for an optical film such as interfacial adhesion, high temperature durability, light leakage resistance, 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 and reworkability, etc., a diblock copolymer may be advantageous.

In one example, the block copolymer may include a crosslinkable functional group. For example, the first block and / or the second block may include a polymer unit derived from a copolymerizable monomer having a crosslinkable functional group. The crosslinkable functional group contained in a block copolymer can form the crosslinked structure of an adhesive, and can provide durability to an adhesion layer.

In one example, the block copolymer may include a crosslinkable functional group except for an acidic functional group. As an acidic functional group, a carboxyl group, a sulfonic acid group, a phosphoric acid group, etc. can be illustrated, for example. When using the monomer containing the acidic functional group, it is possible to corrode the electrode such as ITO.

When the block copolymer includes a crosslinkable functional group except the acidic functional group, the acid value of the block copolymer is 10 or less, for example, 9 or less, 7 or less, 5 or less, 3 or less or 1 or less. Or 0.1 or less. Said "acid value" shows the mg number of potassium hydroxide required to neutralize the free fatty acid, resin acid, etc. which are contained in 1 g of samples.

The kind of crosslinkable functional group except an acidic functional group is not specifically limited. For example, a hydroxyl group, an epoxy group, an isocyanate group or a nitrogen containing functional group can be used. If such a crosslinkable functional group can be provided to a block copolymer, the kind of specific compound will not be restrict | limited in particular. For example, hydroxy group containing monomers, such as hydroxy group alkyl (meth) acrylate or hydroxy alkylene glycol (meth) acrylate, etc .; Epoxy group-containing (meth) acrylic compounds such as glycidyl (meth) acrylate, 2-methylglycidyl acrylate, 3,4-epoxybutyl acrylate, or 6,7-epoxyheptyl acrylate; Or nitrogen-containing monomers such as (meth) acrylamide, N-vinyl pyrrolidone or N-vinyl caprolactam may be used.

In the prior art, in consideration of heating conditions such as general high temperature and / or high humidity where adhesive optical laminates used for TVs, smartphones, tablet PCs, etc. can be placed, the performance of the product is not degraded even within the range of about 60 to 80 ° C. The adhesive layer was designed to have durability. For example, a method of increasing the durability of the pressure-sensitive adhesive layer by introducing a crosslinkable functional group into the pressure-sensitive adhesive forming copolymer has been considered, and the same has been applied to the pressure-sensitive adhesive applied to a vehicle member that can be driven in a cold weather. However, when excessively introducing a crosslinkable functional group to secure durability, that is, when an excessive amount of the monomer containing the crosslinkable functional group is used during polymer formation, excessive gelation proceeds and further polymerization or crosslinking reaction becomes difficult. There was a problem that the function of sufficeably could not be provided or the transparency of the pressure-sensitive adhesive layer was lowered. On the other hand, when the pressure-sensitive adhesive layer is used adjacent to the optical film, it may be considered to introduce an aromatic group into the copolymer for pressure-sensitive adhesive to give an optical compensation effect or light leakage prevention effect to the pressure-sensitive adhesive layer. Specifically, an aromatic group may be introduced through the use of a copolymerizable monomer including a vinyl group and an aromatic group. In order to increase the content of the aromatic group-containing copolymerizable monomer for achieving the above object, the copolymerizable monomer having the aromatic group may be used. As the radicals necessary for the formation of the polymer disappear, obstacles to the formation of the polymer for the pressure-sensitive adhesive, there may be a problem that the physical properties required for the polymer-based pressure-sensitive adhesive is not secured. The above problems become more pronounced when the adhesive is used in harsh conditions. Therefore, while using a relatively small amount of the monomer used to secure the above properties, it is necessary to ensure the durability and light leakage prevention ability of the equivalent or higher than the prior art in the harsh conditions. In view of this point, the inventors of the present application have no problem as described above, and invented a pressure-sensitive adhesive composition capable of providing durability reliability such as excellent interfacial adhesion to an optical film even under severe conditions. The pressure-sensitive adhesive composition includes a block copolymer and a crosslinking agent.

In this regard, the block copolymer of the present application includes (a1) a first monomer including a crosslinkable functional group and (a2) a second monomer including both a crosslinkable functional group and an aromatic group in a second block having a relatively low glass transition temperature. It may include a derived polymer unit. In this case, the (a1) monomer and the (a2) monomer are different from each other. In the present application, the "polymerization unit" may mean a state in which the predetermined monomer is polymerized and contained in a main chain or side chain of a resin, a polymer, or a polymerization reaction product formed by polymerization of a predetermined monomer, which is one impression. In the case of having the configuration as described above, while using a small amount of a monomer providing a crosslinkable functional group and / or an aromatic group in the block copolymer, it is possible to ensure the durability and light leakage prevention ability compared to the prior art or more.

In one example, the second block comprises (a1) 0.5 to 10 parts by weight of the first monomer comprising a crosslinkable functional group, and (a2) 0.5 to parts by weight of the second monomer including both the crosslinkable functional group and the aromatic ring. It may include a polymer unit derived from 10 parts by weight. In the present application, "parts by weight" may mean a weight ratio between components. For example, the fact that the first block includes 80 parts by weight to 99 parts by weight of polymerized units of Compound A and 1 part by weight to 20 parts by weight of polymerized units of Compound B includes compounds A and B that form polymerized units of the first block. The ratio (A: B) based on the weight of the compound may mean 80 to 99.9: 0.1 to 20. Specifically, the second block may include at least 1 part by weight, at least 2 parts by weight, at least 3 parts by weight, at least 4 parts by weight, at least 5 parts by weight, or at least 6 parts by weight of the (a1) first monomer. And (a1) 9.5 parts by weight or less, 9 parts by weight or less, 8.5 parts by weight or less, or 7 parts by weight or less of the first monomer. In addition, the second block may include 0.5 parts by weight or more, 1 parts by weight, 2 parts by weight, 3 parts by weight, 4 parts by weight or 5 parts by weight or more of the (a2) second monomer, and (a2) 9.5 parts by weight or less, 9 parts by weight or less, 8.5 parts by weight or less, 7 parts by weight or less, or 6 parts by weight or less of the second monomer.

In one example, when the crosslinkable functional group provided by the monomer (a1) is a hydroxy group, the monomer (a1) may be represented by the following Chemical Formula 1.

[Formula 1]

However, in Chemical 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 two or more [—O—B—] units are present in Formula 1, the carbon number of B in each [—O—B—] unit may be the same or different.

As used herein, unless otherwise specified, the term alkyl group refers to 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. The alkyl group may be optionally substituted with one or more substituents. Examples of the alkyl group in Formula 1 may include a linear or branched alkyl group having 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms. Although not particularly limited, when Q is an alkyl group in Formula 1, Q may be an alkyl group having 1 to 4 carbon atoms.

As used herein, unless otherwise specified, the term alkylene group or alkylidene group is a straight, branched chain or ring 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. It may mean an alkylene group or an alkylidene group on the phase, which may be optionally substituted by one or more substituents. Although not particularly limited, in Formula 1, for example, A and B may be each independently 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.

As an example of the compound of the said General formula (1), 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) Hydroxy alkyl (meth) acrylates such as) acrylate or 8-hydroxyoctyl (meth) acrylate can be used. Or 2-hydroxyethylene glycol (meth) acrylate, 2-hydroxypropylene glycol (meth) acrylate, and the like may be exemplified as the compound of Formula 1, but are not particularly limited to the compounds listed above.

In one example, the second block may include two species of the compound which may be represented by Formula 1.

In one example, the second block may include a polymerized unit derived from hydroxy alkyl (meth) acrylate having an alkyl group having 1 to 4 carbon atoms. When the chain of an alkyl group becomes long in hydroxy alkyl (meth) acrylate, it may become easier for a hydroxy group to participate in chemical reactions, such as crosslinking, than when the chain of an alkyl group is short. When the crosslinking functional groups involved in the chemical reaction increases, excessive gelation proceeds, and further polymerization or crosslinking reaction becomes difficult, and the function of the adhesive layer cannot be sufficiently provided, or the transparency of the adhesive layer is deteriorated. May occur. In addition, hydroxy alkyl (meth) acrylate having an alkyl group having 5 or more carbon atoms has a sufficient physical crosslinking structure as compared to hydroxy alkyl (meth) acrylate having an alkyl group having 1 to 4 carbon atoms, since the chains are less likely to cause chain entanglement. There is a side that is difficult to provide sufficient interfacial adhesive force required under high temperature and / or high humidity conditions, especially under the harsh conditions in which the pressure sensitive adhesive applied to a vehicle member may be placed at a high temperature. In view of this point, in the present application, hydroxy alkyl (meth) acrylate having a relatively short carbon number of the alkyl group, that is, a carbon number of the alkyl group in the range of 1 to 4 may be used.

In one example, the second block may include polymerized units derived from 5 parts by weight or less of hydroxy alkyl (meth) acrylate having 1 to 4 carbon atoms in the alkyl group. More specifically, hydroxy alkyl (meth) acrylate having 1 to 4 carbon atoms may be used in the range of 4 parts by weight or less, 3 parts by weight or less, and 2 parts by weight or less. In the case of using an excess of the content range, the content of the functional group providing OH may increase, and problems such as gelation described above may occur.

In one example, the crosslinkable functional group included in the monomer (a2) may be the same as the crosslinkable functional group included in the monomer (a1). For example, the crosslinkable functional group included in the monomer (a1) and the monomer (a2) may be a hydroxyl group.

When the crosslinkable functional group provided by the monomer (a2) is a hydroxy group, the monomer (a2) may include a phenoxy group as an aromatic ring.

In one example, the (a2) monomer may be represented by the following formula (2).

[Formula 2]

In Formula 2, R1 is hydrogen or an alkyl group, R2 is an alkylene group or alkylidene group substituted with an OH group which is a crosslinkable functional group, and Ph is a substituted or unsubstituted phenoxy group (C ₆ H ₅ O-). . The kind of the monomer (a2) is not particularly limited, but for example, 2-hydroxy-3-phenoxypropyl (meth) acrylate (2-HYDROXY-3-PHENOXYPROPYL (METH) ACRYLATE), 3- ( 4-methylphenoxy) -2-hydroxypropyl (meth) acrylate (3- (4-METHYLPHENOXY) -2-HYDROXYPROPYL (METH) ACRYLATE), or 1-hydroxy-3-phenoxy-2propanyl ( Meta) acrylate (1-Hydroxy-3-phenoxy-2-propanyl acrylate), and the like can be used.

In one example, the total content of the (a1) monomer and (a2) monomer used in forming the second block may be 15 parts by weight or less. More specifically, the upper limit of the total content of the (a1) monomer and the (a2) monomer is 14 parts by weight or less, 13 parts by weight or less, 12 parts by weight or less, 11 parts by weight or less, 10 parts by weight or less, 9 parts by weight or less, It may be 8 parts by weight or less, 7 parts by weight or less, 6 parts by weight or less, 5 parts by weight or less, 4 parts by weight or less, or 3 parts by weight or less. As shown through the following experimental examples, when using the pressure-sensitive adhesive composition having the configuration of the present application, even if a monomer containing a relatively small amount of crosslinkable functional groups and / or a monomer comprising an aromatic group is used as described above The effect to be achieved through the crosslinkable functional group and the aromatic group can be sufficiently achieved to be equivalent to or higher than that of the prior art without problems of technology.

In order to include the polymerized units derived from the monomer (a1) and the monomer (a2) described above, and to secure the glass transition temperature described above, the second block may include the polymerized unit derived from the (meth) acrylic acid ester monomer. Can be.

In one example, as the (meth) acrylic acid ester used to form the second block, for example, alkyl (meth) acrylate can be used. In consideration of cohesion, glass transition temperature and tack control, alkyl (meth) acrylates having alkyl groups 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 may be used. have. Examples of such monomers are methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, t-butyl (meth ) 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, lauryl (meth) acrylate, and the like. It can be selected to use.

In one example, the second block is 80 to 99 parts by weight of the (meth) acrylic acid ester monomer, (a1) 0.5 to 10 parts by weight of the first monomer comprising a crosslinkable functional group, and (a2) a crosslinkable functional group and It may include a polymerized unit derived from 0.5 to 10 parts by weight of the second monomer containing all the aromatic rings. In another example, the second block is 85 to 98 parts by weight of the (meth) acrylic acid ester monomer, (a1) 0.5 to 10 parts by weight of the first monomer including a crosslinkable functional group, and (a2) the crosslinkable functional group And it may include a polymerized unit derived from 0.5 parts by weight to 10 parts by weight of the second monomer containing both aromatic rings. Even in the above case, as described above, the second block may include two or more (a1) monomers different from each other.

If a block having a glass transition temperature in the above range can be formed, the kind or content of the monomer for forming the first block is not particularly limited.

In one example, the first block may include a polymerized unit derived from (meth) acrylic acid ester. As the (meth) acrylic acid ester used for forming the first block, for example, as in the second block, 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 8 carbon atoms Alkyl (meth) acrylates having an alkyl group of 4 can be used.

In one example, the first block may include a crosslinkable functional group. As the crosslinkable functional group, those mentioned above may be used. In this case, the first block may include a polymer unit derived from 70 to 99 parts by weight of the (meth) acrylic acid ester monomer and 1 to 30 parts by weight of the compound including a crosslinkable functional group.

In one example, the first block is an alkyl (meth) acrylate, a polymerized unit derived from an alkyl methacrylate having an alkyl group having 1 to 3 carbon atoms and a polymerized unit derived from an alkyl methacrylate having an alkyl group having 4 or more carbon atoms. It may include. In the case of having the above configuration, it may further contribute to improving the high temperature durability of the pressure-sensitive adhesive. Specifically, the alkyl (meth) acrylate having an alkyl group having 1 to 3 carbon atoms may be more easily chained than an alkyl (meth) acrylate having 4 or more carbon atoms in the alkyl group, and thus may be a physical substitute for chemical crosslinking. Crosslinking can fully be provided with respect to adhesive resin, and the adhesive layer excellent in high temperature durability can be provided by this. The content between monomers or compounds used to form the first block may be adjusted within the same range as in the content range between the polymerized units derived from the monomers or compounds described above with respect to the first block composition. For example, the first block is derived from a polymerized unit derived from 65 to 85 parts by weight of an alkyl (meth) acrylate having an alkyl group having 1 to 3 carbon atoms and from 5 to 14 parts by weight of an alkyl (meth) acrylate having an alkyl group having 4 or more carbon atoms. And a polymerized unit derived from 1 to 30 parts by weight of a compound containing a polymerized unit and a crosslinkable functional group.

In one example, the crosslinkable functional group included in the first block may be a hydroxyl group, an epoxy group, an isocyanate group, or a nitrogen-containing functional group. In this case, examples of the compound capable of providing a crosslinkable functional group in forming the first block are as described above.

In one example, the crosslinkable functional group included in the first block may be a hydroxyl group, and in this case, the compound including the crosslinkable functional group used to form the first block may be a compound represented by Chemical Formula 1.

In one example, the first block may include a polymerized unit derived from alkyl methacrylate, and the second block may include a polymerized unit derived from alkyl acrylate. The first block containing the alkyl methacrylate is advantageous in securing durability because the glass transition temperature is high, and the second block containing the alkyl acrylate is advantageous in implementing the adhesive performance because the glass transition temperature is low.

The first block and / or the second block may further include any comonomer as necessary, and the monomer may be included in each block as a polymer unit. As said comonomer, it is (meth) acrylonitrile, (meth) acrylamide, N-methyl (meth) acrylamide, N-butoxy methyl (meth) acrylamide, N-vinyl pyrrolidone, or N-vinyl capro Nitrogen-containing monomers such as lactams and the like; Styrene-based monomers such as styrene or methyl styrene; Or carboxylic acid vinyl esters such as vinyl acetate, but are not limited thereto. Such comonomers may be included in the polymer by selecting one or more kinds thereof as necessary. Polymerized units derived from such comonomers may be included in, for example, 20 parts by weight or less, or 0.1 to 15 parts by weight in each block.

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 prepared by polymerizing only the monomers forming the first block. The number average molecular weight mentioned in the present application may be measured, for example, using a gel permeation chromatograph (GPC) according to the method given in the following experimental example. More specifically, the number average molecular weight Mn of the first block may be, for example, a 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 150,000 or less, 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, or 70,000 or less.

In another example, the ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the first block, that is, the molecular weight distribution (PDI = Mw / Mn) may range from 1.0 to 3.0. have. More specifically, the lower limit of the PDI value of the first block may be 1.0 or more, 1.1 or more, 1.2 or more, 1.3 or more, 1.4 or more, or 1.5 or more. The upper limit may be 3.0 or less or 2.5 or less, and more specifically, 2.4 or less, 2.3 or less, 2.2 or less, 2.1 or less, 2.0 or less, 1.9 or less, 1.8 or less, or 1.7 or less.

In one example, the block copolymer may have a number average molecular weight (Mn) of 350,000 or less. More specifically, the number average molecular weight (Mn) of the block copolymer is, for example, the lower limit of 50,000 or more, 60,000 or more, 70,000 or more, 80,000 or more, 90,000 or more, 100,000 or more, 110,000 or more, 120,000 or more, 130,000 or more, or It may be more than 140,000. And the upper limit may be 300,000 or less or 250,000 or less, specifically 200,000 or less, 190,000 or less, 180,000 or less, 180,000 or less, or 170,000 or less.

In another example, the molecular weight distribution (PDI = Mw / Mn) of the block copolymer may be in the range of 3.0 to 5.5. More specifically, the lower limit of the molecular weight distribution of the block copolymer may be, for example, 3.5 or more, specifically 3.6 or more, 3.7 or more, 3.8 or more, 3.9 or more, 4.0 or more, 4.1 or more, 4.2 or more, or 4.3 or more. The upper limit may be, for example, 5.4 or less, 5.3 or less, 5.2 or less, 5.1 or less, or 5.0 or less.

As described above, when adjusting the molecular weight characteristics of the block copolymer, it is possible to form the pressure-sensitive adhesive that is excellent in the required physical properties of the optical film, such as interfacial adhesion, high temperature durability reliability, light leakage prevention properties and reworkability.

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 of the configuration and 50 parts by weight to 95 parts by weight of the second block of the configuration.

In another example, the block copolymer may comprise a relatively excess of a second block. Specifically, the block copolymer may include 10 to 35 parts by weight of the first block of the configuration and 65 to 90 parts by weight of the second block of the configuration. In another example, the block polymer of the present application may include 15 to 30 parts by weight of the first block of the configuration and 70 to 85 parts by weight of the second block of the configuration. When the content of the first block is included in an excessive amount, the catalyst may be precipitated or the block copolymer synthesis may be disturbed due to the polarity difference between the first block and the second block.

In one example, the pressure-sensitive adhesive may include an isocyanate compound as a crosslinking agent. Although not particularly limited, polyfunctional isocyanate compounds may be used. For example, diisocyanate compounds, such as tolylene diisocyanate, xylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isoborone diisocyanate, tetramethyl xylene diisocyanate, or naphthalene diisocyanate; Or a compound obtained by reacting at least one of the diisocyanate compounds with a polyol (eg, trimethylol propane).

In one example, the crosslinking agent may be used in 0.01 to 10 parts by weight based on 100 parts by weight of the block copolymer. More specifically, the crosslinking agent may be used in an amount of 0.05 parts by weight or more or 0.1 parts by weight or more, and 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 part by weight or less. When used in the above content range, it is possible to impart an appropriate level of gel fraction, cohesion, adhesion and durability to the pressure-sensitive adhesive formed cross-linked structure.

The method for producing the block copolymer is not particularly limited, and known methods can be used. For example, the block polymer may be polymerized by LRP (Living Radical Polymerization). Specifically, an anionic polymerization method and an organic alkali metal compound are polymerized using an organic rare earth metal complex as a polymerization initiator or an organic alkali metal compound as a polymerization initiator and synthesized in the presence of an inorganic acid salt such as a salt of an alkali metal or an alkaline earth metal. Anionic polymerization method synthesized in the presence of an organoaluminum compound using an initiator, atomic transfer radical polymerization method (ATRP) using an atom transfer radical polymerization agent as a polymerization control agent, and an atomic transfer radical polymerization agent as a polymerization control agent are used. Activators Regenerated by Electron Transfer (ARRP) Atomic Radical Polymerization (ATRP), Initiators for continuous activator regeneration (ICAR), and Reversible Addition of Inorganic Reductants Reversible addition-cleavage chain transfer using cleavage chain transfer agents And the polymerization (RAFT), or organic Tel method of using the tellurium compound as an initiator of the like can be used, a suitable method is selected from among the method may be that the block copolymer produced.

In one example, the adhesive composition may further include a silane coupling agent. The type of silane coupling agent is not particularly limited, but may be, for example, a silane coupling agent having a β-cyanoacetyl group. The content of the silane coupling agent is not particularly limited, but may be used within the range of 0.01 to 5 parts by weight based on 100 parts by weight of the block copolymer.

The pressure-sensitive adhesive composition may further include a tackifier as necessary. As the tackifier, for example, a hydrocarbon resin or a hydrogenated substance thereof, a rosin resin or a hydrogenated substance thereof, a rosin ester resin or a hydrogenated substance thereof, a terpene resin or a hydrogenated substance thereof, a terpene phenol resin or a hydrogenated substance 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.

In addition, the 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 kind or content of the additive is not particularly limited.

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

In another example of the present application, the present application is directed to a pressure-sensitive adhesive optical laminate. Exemplary optical laminates may include an optical film, a glass substrate, and an adhesive (direct) layer located directly on one surface of the glass substrate. In this case, the adhesive layer may be located between the optical film and the glass substrate.

The pressure-sensitive adhesive layer contains a cured product or a crosslinked product of the pressure-sensitive adhesive composition described above. That is, the pressure-sensitive adhesive composition may be included in the pressure-sensitive adhesive layer in a state of implementing a crosslinked structure.

In one example, the glass substrate may be a configuration 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 for protecting the polarizer, and the adhesive layer may be used to attach the polarizer and the glass substrate or may be opposite to the glass substrate where the glass substrate and the polarizer contact each other. It can be positioned on and used to bond other members with the glass substrate.

In another example, the glass substrate may be a configuration separate from the optical film. For example, the glass substrate may be a part of the liquid crystal panel as a structure confining the liquid crystal layer, and in this case, the adhesive layer may be used to attach the polarizing plate and the 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 automotive optical film may be placed in more severe conditions than typical high temperature and / or high humidity conditions on which optical films used for TVs, smartphones, tablet PCs, and the like may be placed. For example, an automotive optical film can be driven under harsh conditions where the drive temperature in which it is used exceeds, for example, 80 ° C or 100 ° C.

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

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

The kind of polarizer contained in a polarizing plate is not specifically limited, For example, the general kind known in this field, such as a polyvinyl alcohol-type polarizer, can be employ | adopted without a restriction | limiting.

The polarizer is a functional film that can extract 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 in a polyvinyl alcohol resin film. Polyvinyl alcohol-type resin which comprises a polarizer can be obtained by gelatinizing polyvinylacetate-type resin, for example. In this case, the polyvinylacetate-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 with the above. Examples of the monomer copolymerizable with vinyl acetate include one or two or more kinds of unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids and acrylamides having an ammonium group, but are not limited thereto. no. The degree of gelation of the polyvinyl alcohol-based resin is usually 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. Also, 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 a step of stretching (ex. Uniaxial stretching) the polyvinyl alcohol resin film as described above, a step of dyeing the polyvinyl alcohol resin film with a dichroic dye, adsorbing the dichroic dye, and a dichroic dye adsorbed. The polyvinyl alcohol-based resin film can be produced through a process of treating with a boric acid aqueous solution and a process of washing with water after treating with a boric acid aqueous solution. As the dichroic dye, iodine or a dichroic organic dye may be used.

The polarizer may include, in addition to the polarizer, 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 sides of the polarizer, in this case, the adhesive layer of the above-described configuration may be formed on one or both sides of the protective film. The type of protective film is not particularly limited. For example, the protective film may be a glass substrate, or may be a substrate including a polymer component. For example, cellulose-based films such as triacetyl cellulose (TAC); Polyester film such as polycarbonate film or PET (poly (ethylene terephthalet)); Polyether sulfone-based film; Alternatively, one or two or more laminated films such as a polyethylene film, a polypropylene film, or a polyolefin-based film manufactured using a resin having a cyclo or norbornene structure, an ethylene-propylene copolymer, or the like may be used as the protective film. The protective film may have a laminated structure of two or more.

In one example, the polarizer may also further include one or more optical functional films selected from the group consisting of reflective films, antiglare films, retardation films, wide viewing angle compensation films, and brightness enhancement films. The optical functional film may have a laminated structure of two or more.

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 has a refractive index of nx ≠ ny = nz. In this case, nx> ny is + A film and nx <ny is -A film. . The term 'B film' means a film that has a refractive index of nx ≠ ny ≠ nz, and a case where nx> ny> nz is -B film and a case where nz> nx> ny is + B film. "C film" means a film whose refractive index satisfies nx = ny ≠ nz. In this case, a case where ny <nz is + C film and ny> nz is called -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, nz is the film Or the refractive index in the thickness direction of the plate.

In one example, the polarizer may include a retardation film. As the retardation layer, for example, a quarter wave plate (QWP) may be used. The quarter wave plate may have quarter wave phase delay characteristics. As used herein, the term n-wavelength phase retardation characteristic means a characteristic capable of retarding incident light by n times the wavelength of the incident light within at least a portion of the wavelength range. The quarter-wave phase retardation characteristic may be a characteristic of converting incident linearly polarized light into elliptical polarization or circularly polarized light, and converting incident elliptical polarization 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 may be used. For example, uniaxially stretched cycloolefin-based films, uniaxially stretched polyethylene terephthalate films, uniaxially stretched polycarbonate films or liquid crystal films and the like can be used without limitation.

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

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

The crosslinking agent included in the pressure-sensitive adhesive composition in the coating process is preferably controlled from the crosslinking reaction of the functional group from the viewpoint of performing a uniform coating process. Through this, the crosslinking agent may form a crosslinked structure in the curing and aging process after the coating operation to improve the cohesive force of the pressure-sensitive adhesive, improve adhesive properties and cuttability (cuttability).

The coating process is also preferably carried out after sufficiently removing the bubble-inducing components such as volatile components or reaction residues in the pressure-sensitive adhesive composition, so that the crosslinking density or molecular weight of the pressure-sensitive adhesive is too low to lower the elastic modulus, at a high temperature Bubbles existing between the glass plate and the adhesive layer may be increased to prevent a problem of forming scatterers therein.

After coating, the method of curing the pressure-sensitive adhesive composition to implement a crosslinked structure is not particularly limited. For example, the crosslinking reaction between the block copolymer and the crosslinking agent included in the coating layer may be induced in a manner such as maintaining the coating layer at an appropriate temperature.

In one example, the pressure-sensitive adhesive layer may have a peel force of at least 800 gf / 25mm, at least 850 gf / 25mm, or at least 900 gf / 25mm to a glass substrate at a temperature in the range 20 to 30 ℃. Although not particularly limited, the lower limit of the peeling force may be 1,500 gf / 25mm or less, 1,400 gf / 25mm or less, 1,300 gf / 25mm or less, 1,200 gf / 25mm or less, 1,100 gf / 25mm or 1,000 gf / 25mm or less. When the peeling force exceeds the above range, the re-peelability required as required in the process may not be good, and when less than the above range, the adhesiveness may not be sufficient.

In another example of the present application, 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 the optical laminate attached to one side 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, a pixel electrode, a first alignment layer, a liquid crystal layer, a second alignment layer, a common electrode, and a second substrate sequentially formed. 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 through the above-described pressure-sensitive adhesive layer.

The device may further comprise a light source on the side opposite to the viewer side of the liquid crystal panel. For example, an active driving circuit including a TFT (Thin Film Transistor), wiring, and the like may be formed on the first substrate on the light source side as a driving element electrically connected to the transparent pixel electrode. The pixel electrode may include, for example, indium tin oxide (ITO) or the like, 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.

Liquid crystal panels in the apparatus include, for example, passive matrix panels such as twisted nematic (TN) type, super twisted nematic (STN) type, ferroelectic (F) type or polymer dispersed (PD) type; Active matrix panels, such as two-terminal or three-terminal; All known panels, such as an In Plane Switching (IPS) panel and a Vertical Alignment (VA) panel, can be applied.

Other configurations of the display device, for example, the upper and lower substrates such as the color filter substrate or the array substrate in the 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 may be provided that suppresses side effects due to excessive use of a monomer for introducing a crosslinkable functional group and an aromatic group, and has excellent durability even under severe conditions. In addition, according to the present application, since the pressure-sensitive adhesive composition does not include an acidic functional group, it is possible to prevent corrosion of the display device.

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

<Measurement or evaluation item>

1. Molecular Weight

The number average molecular weight (Mn) and molecular weight distribution (PDI) of the block or block copolymer were measured using a gel permeation chromatograph (GPC), and the GPC measurement conditions were as follows. In the preparation of the calibration curve, measurement results were converted using standard polystyrene (manufactured by Aglient system).

<GPC measurement condition>

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

Column: Connect 2 PL Mixed B

Column temperature: 40 ℃

Eluent: THF (Tetrahydrofuran)

Flow rate: 1.0mL / min

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

2. Glass transition temperature

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

[Formula A]

1 / Tg = ∑Wn / Tn

In the above formula, Wn is a weight fraction of a block copolymer or a monomer applied to each block of the copolymer, and Tn represents a glass transition temperature when each monomer forms a homopolymer. In other words, the right side in Equation A is the result of adding up the calculated values after calculating all the monomers (Wn / Tn) divided by the weight fraction of the monomers used by the glass transition temperature when the monomers form a homopolymer. to be.

3. Durable

The polarizing plates produced 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 19 inch commercial liquid crystal panel. Thereafter, the liquid crystal panel with a polarizing plate was stored in an autoclave (50 ° C. 5 atm) for about 20 minutes to prepare a sample. Heat and moisture resistance was evaluated according to the following criteria after leaving the samples prepared at 65 ° C. and 95% relative humidity for 500 hours. The heat resistance was evaluated according to the following criteria after the prepared samples were maintained at 95 ° C. and 105 ° C. for 500 hours, respectively.

<Evaluation criteria for heat and moisture resistance>

A: No bubble and peeling occurrence

B: Bubbles and / or peeling slightly generated

C: Large amount of bubbles and / or exfoliation

4. Corrosive

The pressure-sensitive adhesive polarizers prepared in Examples and Comparative Examples were cut to have a width of about 50 mm and a length of about 50 mm, and attached to a metal (copper, aluminum, etc.) surface. The sample was then left for 1,000 hours at a temperature of 60 ° C. and a relative humidity of 90% and the degree of corrosion was assessed according to the following criteria.

Corrosion Evaluation Criteria

A: No corrosion of metal surface due to no corrosion

B: Partial discoloration due to slight corrosion

C: discoloration of metal surface due to corrosion

5. Peeling force

The adhesive polarizing plates prepared in Examples and Comparative Examples were cut to have a width of 25 mm and a length of 100 mm to prepare specimens. Next, the release PET film adhered to the pressure-sensitive adhesive layer is peeled off, and the pressure-sensitive adhesive polarizing plate is attached to the soda lime glass using a roller of 2 kg in accordance with JIS Z 0237. Samples were prepared by pressing the glass with a polarizing plate for about 20 minutes in an autoclave (50 ° C., 5 atmospheres) and storing for 24 hours at constant temperature and humidity conditions (23 ° C., 50% relative humidity). Thereafter, the TA force (Texture Analyzer, manufactured by Stable Micro Systems Co., Ltd.) was used to measure the peeling force while peeling the polarizing plate from the glass at a peel rate of 0.3 m / min and a 180 ° peel angle.

6. Interfacial adhesion

The adhesive polarizing plates prepared in Examples and Comparative Examples were cut to have a horizontal length of 50 mm and a vertical length of 100 mm to prepare specimens. Thereafter, the adhesive surface of the specimen is attached to a tape having a strong adhesive strength (American Tape, Inc.), and then pressed using a 2 kg roller and left at room temperature for 10 minutes. Then, the adhesive tape is peeled off from the pressure-sensitive adhesive layer and the adhesive surface is separated from the polarizing plate interface to measure the area transferred to the tape (Table 2).

<Evaluation Criteria>

A: Residual area to the tape of the adhesive is less than 5%

B: Residual area of the adhesive to the tape is 5% to 30%

C: 30% or more of residue area to adhesive tape

7. Creep Characteristics

The adhesive polarizing plate prepared in Example or Comparative Example was cut to have a width of 10 mm and a length of 90 mm to prepare a specimen. Subsequently, after peeling the PET film to 1cm X 1cm (sodalime glass), the sample was prepared by aging at room temperature for 3 days. Then, the distance (um) in which the adhesive was pushed was measured, using TA apparatus (Texture Analyzer, the UK Stable Microsystem Co., Ltd.), peeling the said polarizing plate from glass at 180 degree peeling angle with the constant force of 1 kgf.

<Production Example of Copolymer>

Preparation Example 1 Preparation of Block Copolymer (A1)

0.032 g of ethyl 2-bromoisobutyrate (EBiB) and 17.5 g of methyl methacrylate (MMA), 2.5 g of butyl methacrylate (BMA) and 1.1 g of hydroxy ethyl methacrylate (HEMA) were added to 8.1 g of ethyl acetate (EAc). Mixed. The reactor containing the mixture was sealed, purged with nitrogen at about 25 ° C. for about 30 minutes, and dissolved oxygen was removed via bubbling. Then, 0.004 g of CuBr2, 0.009 g of tris (2-pyridylmethyl) amine) and 0.023 g of V-65 (2,2'-azobis (2,4-dimethyl valeronitrile)) were added to the oxygen-free mixture. The reaction was initiated in a reactor at about 67 ° C. (polymerization of the first block). When the conversion rate of methyl methacrylate is about 70%, 73.8 g of butyl acrylate (BA) previously bubbled with nitrogen, 1.15 g of hydroxybutyl acrylate (HBA), and hydroxy phenoxy propyl acrylate (HPPA) A mixture of 0.75 g and 100 g ethyl acetate (EAc) was added 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). Block copolymers were prepared by exposing the reaction mixture to oxygen and terminating the reaction by dilution with an appropriate solvent when the conversion of monomer (BA) reached 80% or more (in the process V-65 takes into account its half-life). It was appropriately divided up to the end of the reaction.

Preparation Examples 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 to the ratios shown in Table 1 below.

TABLE 1

Production Example  6. Preparation of Random Copolymer (B1)

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

Preparation Example 7 Preparation of Random Copolymer (B2)

A mixture of monomers consisting of 94.5 parts by weight of n-butylacrylate (BA) and 5.5 parts by weight of acrylic acid was added to a 1L reactor equipped with a refrigeration system to allow nitrogen gas to be refluxed and to facilitate temperature control. Then, 250 parts by weight of ethylacetate (EAc) was added as a solvent. After purging with nitrogen gas for 60 minutes to remove oxygen, the temperature is maintained at 60 ° C., and 0.06 parts by weight of azobisisobutyronitrile (AIBN), a reaction initiator, is added and reacted for 8 hours. Copolymer (B2) was prepared. The weight average molecular weight was 1.1 million and molecular weight distribution 6.3.

<Examples and Comparative Examples>

Example 1

Preparation of coating liquid (adhesive composition): 0.15 parts by weight of crosslinking agent (Coronate L, manufactured by Japan NPU), 0.1 part by weight of DBTDL (Dibutyltin dilaurate), and beta cyanate based on 100 parts by weight of the block copolymer (A1) prepared in Preparation Example 1. 0.2 weight part of silane coupling agents (M812, LG Chemical) which have a noacetyl group were mixed, and ethyl acetate was mix | blended as a solvent, and it adjusted so that coating solid content might be about 30 weight%, and the coating liquid (adhesive composition) was prepared.

Preparation of adhesive polarizing plate: The prepared coating solution was coated on a release treated surface of a release poly (ethylene terephthalate) PET (MRF-38, manufactured by Mitsubishi) having a thickness of 38 μm, which was release-treated, and then about 3 minutes in an oven at 95 ° C. It was maintained for about 23 μm after drying. After drying, the coating layer formed on the release PET was laminated on one surface of the polarizing plate (lamination structure of COP / PVA / COP: COP = cyclopolyolefin, PVA = polyvinyl alcohol-based polarizing film) to prepare an adhesive polarizing plate.

Examples 2-4 and Comparative Examples 1-3

The pressure-sensitive adhesive composition (coating liquid) and the pressure-sensitive adhesive polarizing plate were prepared in the same manner as in Example 1 except that each component and the ratio were adjusted as shown in Table 2 at the time of preparing the pressure-sensitive adhesive composition (coating liquid).

TABLE 2

Physical property evaluation results for the Examples and Comparative Examples are shown in Table 3 below.

TABLE 3

From Table 3, when the pressure-sensitive adhesive composition includes a block copolymer having blocks having different glass transition temperatures from each other (Examples and Comparative Examples 1 to 2), a pressure-sensitive adhesive composition containing a random copolymer that is not used (Comparative Example) 3) it can be seen that it provides a better adhesion. In particular, in the case where the second block, which is a soft segment in the block copolymer, has the same structure as in Example, even if the content of the compound providing the crosslinkable functional group (-OH) is used less than that of Comparative Examples 1 and 2, It can be seen that even under harsh conditions, excellent durability can be provided and greater peel force is provided.

Even in the case of the random copolymer, in Comparative Example 4 including a carboxyl group, since the carboxyl group forms a strong hydrogen bond with the glass interface, it has a higher adhesive strength than Comparative Example 3, but the crab adhesion is not good and there is a corrosion problem.

Claims (17)

A first block having a glass transition temperature of 50 ° C. or higher; And a block copolymer having a crosslinkable functional group and having a second block having a glass transition temperature of −10 ° C. or less,
The second block is a pressure-sensitive adhesive composition comprising (a1) a first monomer containing a crosslinkable functional group and (a2) a polymerized unit derived from a second monomer containing both a crosslinkable functional group and an aromatic ring. The pressure-sensitive adhesive composition of claim 1, wherein the first block and the second block include polymerized units derived from a (meth) acrylic acid ester monomer. The method according to claim 2, wherein the second block is 80 to 99 parts by weight of the (meth) acrylic acid ester monomer, (a1) 0.5 to 10 parts by weight of the first monomer comprising a crosslinkable functional group, and (a2) the crosslinkable functional group And a polymerized unit derived from 0.5 parts by weight to 10 parts by weight of the second monomer including both aromatic rings. According to claim 2, wherein the second block (a1) 15 parts by weight or less of the polymerized unit derived from the first monomer containing a crosslinkable functional group and (a2) the second monomer containing both a crosslinkable functional group and an aromatic ring Pressure-sensitive adhesive composition comprising. The pressure-sensitive adhesive composition of claim 1, wherein the second block comprises hydroxy alkyl (meth) acrylate as the first monomer including the (a1) crosslinkable functional group. The pressure-sensitive adhesive composition of claim 5, wherein the second block comprises hydroxy alkyl (meth) acrylate having an alkyl group having 1 to 4 carbon atoms. The pressure-sensitive adhesive composition of claim 6, wherein the second block comprises polymerized units derived from 5 parts by weight or less of hydroxy alkyl (meth) acrylate having 1 to 4 carbon atoms in the alkyl group. The pressure-sensitive adhesive composition of claim 2, wherein the first block has a crosslinkable functional group. The pressure-sensitive adhesive composition of claim 8, wherein the first block comprises 70 to 99.9 parts by weight of a (meth) acrylic acid ester monomer and 0.1 to 30 parts by weight of a polymer unit derived from a monomer providing a crosslinkable functional group. The pressure-sensitive adhesive composition of claim 9, wherein the first block comprises an alkyl (meth) acrylate having 1 to 3 carbon atoms in the alkyl group and an alkyl (meth) acrylate having 4 to 20 carbon atoms in the alkyl group. The pressure-sensitive adhesive composition of claim 8, wherein the block copolymer does not include an acidic functional group. The pressure-sensitive adhesive composition of claim 2, wherein the first block comprises a polymerized unit derived from alkyl methacrylate, and the second block comprises a polymerized unit derived from alkyl acrylate. The pressure-sensitive adhesive composition of claim 1, wherein the first block has a number average molecular weight (Mn) within a range of 2,500 to 150,000 and a molecular weight distribution (PDI) within a range of 1.0 to 3.0. The pressure-sensitive adhesive composition of claim 1, wherein the block copolymer has a number average molecular weight (Mn) in a range of 50,000 to 350,000 and a molecular weight distribution (PDI) in a range of 3.0 to 5.5. 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, further comprising an isocyanate compound as a crosslinking agent.
Optical film; Glass substrates; And a pressure-sensitive adhesive layer comprising a pressure-sensitive adhesive layer directly positioned on one surface of the glass substrate, the pressure-sensitive adhesive composition comprising a crosslinking agent and a block copolymer,
The block copolymer may have a glass transition temperature of 50 ° C. or higher and a first block having a crosslinkable functional group; And a second block comprising a polymer unit derived from a second monomer having a glass transition temperature of −10 ° C. or less and comprising (a1) a crosslinkable functional group and (a2) a crosslinkable functional group and an aromatic ring. Including,
The optical film is an optical laminate that is driven within the range of 80 to 150 ℃.