KR102079138B1 - Pressure-sensitive adhesive polarizing plate - Google Patents

Abstract

The present application relates to an adhesive polarizing plate and a display device. The present application can provide an adhesive composition that is excellent in heat and moisture and heat endurance reliability, and can minimize light leakage even when exposed to harsh conditions such as high temperature or high temperature and high humidity.

Description

Pressure-sensitive adhesive polarizing plate

The present application relates to an adhesive polarizing plate, and a display device including the same.

A liquid crystal display device (hereinafter referred to as "LCD device") is a liquid crystal panel including a liquid crystal component injected between two transparent substrates and, for example, optics such as a polarizing film, a retardation film, or a brightness enhancing film. It is generally configured to include a functional film. In addition, an adhesive is mainly used for lamination between the optically functional films and adhesion of the optically functional film to the liquid crystal panel.

Since the components of the liquid crystal display device listed above are made from different materials and have different physical properties, the dimensional stability between parts may deteriorate and warp may occur under high temperature and / or moist heat conditions. In addition, the thinning of the display can increase the warpage problem.

On the other hand, in order to impart warpage-preventing properties to the adhesive for optical films, a method of reducing the degree of crosslinking of the main component polymer of the adhesive may be considered, but such a method degrades reworkability due to problems such as the adhesive sticking out during cutting, , Since the durability of the pressure-sensitive adhesive is reduced while increasing the change over time under pressure-resistant and / or heat-resistant conditions, there is a problem in that it is difficult to actually use the pressure-sensitive adhesive.

One object of the present application is to provide an adhesive polarizing plate and a display device including the same.

Another object of the present application is to provide an adhesive polarizing plate and a display device including the same, which are excellent in durability reliability even under severe conditions such as high temperature and high humidity, and can improve the light leakage phenomenon due to bending.

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

This application relates to optical members. More specifically, the present application relates to an adhesive optical member provided with an adhesive layer on at least one surface of the optical member. As the optical member, an optical functional film such as a polarizing film, a retardation film, or a brightness enhancing film may be used. In one example, when a polarizing film is used as the optical member, the adhesive optical member may be referred to as an adhesive polarizing plate.

The polarizing film may be a functional film capable of extracting only light that vibrates in one direction from light incident while vibrating in various directions. The type of polarizing film that can be used is not particularly limited. For example, a general polarizing film known in the art, such as a polyvinyl alcohol-based polarizing film in which a dichroic dye is adsorbed and oriented in a polyvinyl alcohol-based film, can be used without limitation. The polyvinyl alcohol-based resin used in the polarizing film 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 with the above. Examples of monomers copolymerizable with vinyl acetate include, but are not limited to, unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having ammonium groups, or mixtures of two or more. no. The gelation degree of the polyvinyl alcohol-based resin is usually about 85 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 usually about 1,000 to 10,000, preferably about 1,500 to 5,000.

The polarizing film is a step of stretching (ex. Uniaxially stretching) a polyvinyl alcohol-based resin film, a step of dyeing a polyvinyl alcohol-based resin film with a dichroic dye, adsorbing the dichroic dye, and adsorbing the dichroic dye The prepared polyvinyl alcohol-based resin film may be prepared 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. In the above, as the dichroic dye, iodine or dichroic organic dye may be used.

In one example, a protective film may be additionally provided on one side or both sides of the polarizing film, that is, the optical member, and in this case, the pressure-sensitive adhesive layer may be provided on one side of the protective film. The type of the protective film that can be used is not particularly limited, for example, a cellulose-based film such as triacetyl cellulose; Polyester-based films such as polycarbonate films or polyethylene terephthalate films; Polyether sulfone-based films; And / or a polyethylene film, a polypropylene film, a polyolefin film having a cyclo-based or norbornene structure, or a polyolefin-based film such as an ethylene propylene copolymer. The thickness of the protective film is not particularly limited.

The method of forming the pressure-sensitive adhesive layer on the optical member such as the polarizing film is not particularly limited. For example, by applying a pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer mentioned below using a bar coater, etc., or curing, or after applying and curing the pressure-sensitive adhesive composition on the surface of the peelable substrate and then transferring it onto a polarizing film, etc. Can be used.

The pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer may include a crosslinkable block copolymer (A) and a non-crosslinkable random copolymer (B). In the present application, the fact that a component is included in the adhesive composition can be interpreted in the same way that the component is included in the adhesive layer. However, when the crosslinkable block copolymer is included in the pressure-sensitive adhesive layer and when included in the pressure-sensitive adhesive composition, it may be in a different state. For example, the crosslinkable block copolymer (A) may be in a state that does not crosslink each other in the composition, but may be in a crosslinked state within the adhesive layer. In the present application, the term "block copolymer" may refer to a copolymer comprising blocks of different polymerized monomers.

The block copolymer (A) may include a first block having a glass transition temperature of 50 ° C or higher and a second block having a glass transition temperature of -10 ° C or lower. In the present application, the "glass transition temperature" of each block constituting the block copolymer may mean a glass transition temperature measured from a polymer formed of only the monomers included in the block, and the method described in connection with the following experimental examples It can be measured accordingly.

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, 80 ° C or higher, or 90 ° C or higher. The upper limit of the glass transition temperature of the first block is not particularly limited, but may be, for example, 150 ° C or less, 140 ° C or less, 130 ° C or less, or 120 ° C or less.

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, -40 ° C or less, or -50 ° C or less. The lower limit of the glass transition temperature of the second block is not particularly limited, but may be, for example, -80 ° C or higher, -70 ° C or higher, or -60 ° C or higher.

Since the block copolymer (A) including both blocks satisfying the glass transition temperature range can form a fine phase separation structure in the adhesive, and exhibits appropriate cohesion and stress relaxation properties according to temperature changes , It is possible to form an adhesive that maintains excellent physical properties required for an optical film such as interfacial adhesion, durability reliability, light leakage prevention properties, and reworkability.

In one example, the weight average molecular weight (Mw: Weight Average Molecular Weight) of the first block of the block copolymer (A) may range from 10,000 to 50,000. The weight average molecular weight of the first block may be, for example, a weight average molecular weight of a polymer prepared by polymerizing only the monomers forming the first block. In the present application, the weight molecular weight may be measured according to the method presented in the following examples using, for example, GPC (Gel Permeation Chromatograph). More specifically, the weight average molecular weight (Mw) of the first block may be, for example, in the range of 20,000 to 40,000.

In one 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. More specifically, the lower limit of the molecular weight distribution of the first block may be 1.1 or more, 1.2 or more, or 1.3 or more, and the upper limit may be 2.4 or less, 2.2 or less, 2.0 or less, 1.8 or less, or 1.6 or less.

In one example, the block copolymer (A) may have a weight average molecular weight (Mw) of 100,000 or more. The upper limit of the block copolymer weight average molecular weight (Mw) may be appropriately controlled in consideration of the physical properties of the pressure-sensitive adhesive layer, and may be, for example, 1,000,000.

In one example, the molecular weight distribution (PDI = Mw / Mn) of the block copolymer (A) may be 1.0 to 3.0. More specifically, the lower limit of the molecular weight distribution may be 1.4 or more, 1.5 or more, or 1.6 or more, and the upper limit may be 2.8 or less, 2.7 or less, or 2.6 or less.

As described above, when adjusting the molecular weight properties of the block copolymer, to form a pressure-sensitive adhesive that maintains excellent physical properties required for the adhesive optical member, for example, interface adhesion, durability, light leakage prevention properties and reworkability, etc. You can.

The block copolymer (A) may be a crosslinkable block copolymer having a crosslinkable functional group. More specifically, the block copolymer may include a copolymerizable monomer having a crosslinkable functional group in a polymerized form in the block.

Examples of the crosslinkable functional group include a hydroxy group, a carboxyl group, an epoxy group, an isocyanate group, or a nitrogen-containing functional group. The type of the copolymerizable monomer having the crosslinkable functional group is not particularly limited, for example, a hydroxy group-containing monomer such as hydroxy group alkyl (meth) acrylate or hydroxy alkylene glycol (meth) acrylate; (Meth) acrylic acid, 2- (meth) acryloyloxy acetic acid, 3- (meth) acryloyloxy propylic acid, 4- (meth) acryloyloxy butyric acid, acrylic acid doublets, itaconic acid, maleic acid and Carboxyl group-containing monomers such as maleic anhydride or nitrogen-containing monomers such as (meth) acrylamide, N-vinyl pyrrolidone, or N-vinyl caprolactam may be used alone or in combination of two or more.

The crosslinkable functional group may be included in the second block having a relatively low glass transition temperature. In one example, the crosslinkable functional group is included only in the second block, and may not be included in the first block. When the crosslinkable functional group is included in the second block, the adhesive layer exhibits appropriate cohesion and stress relaxation according to temperature change, thereby forming an adhesive layer that maintains excellent physical properties such as interfacial adhesion, durability reliability, light leakage prevention properties, and reworkability. can do.

The crosslinkable block copolymer (A) may be an acrylic polymer.

In one example, the first block may include an alkyl (meth) acrylate monomer in a polymerized form in order to secure the glass transition temperature range. In the present application, that a monomer or a polymer is contained in a polymerized form may mean that the monomer undergoes a polymerization reaction to form a skeleton, eg, a main chain or a side chain, of the block or polymer.

In the first block formation, 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. 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 And bornyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, and lauryl (meth) acrylate.

In one example, in consideration of the ease of adjusting the glass transition temperature, the first block is formed with 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. Eggplant alkyl methacrylates can be used. More specifically, the first block is 60 to 80 parts by weight of an alkyl methacrylate having an alkyl group having 1 to 3 carbon atoms, and 20 to 40 parts by weight of an alkyl methacrylate having an alkyl group having 4 to 10 carbon atoms in a polymerized form. It can contain. In the present application, the term "parts by weight" may mean a weight ratio between components. For example, the first block is from 60 to 80 parts by weight of an alkyl methacrylate (a) having an alkyl group having 1 to 3 carbon atoms and from 20 to 40 parts by weight of an alkyl methacrylate (b) having an alkyl group having 4 to 10 carbon atoms. Including the derived polymerization unit may mean a case where the weight ratio of the monomer (a) and the monomer (b) forming the polymerized unit of the first block is in the range of 60 to 80:20 to 40.

In one example, the first block may be a polymer of only alkyl (meth) acrylate monomers. Specifically, in order to form the first block, only an alkyl (meth) acrylate monomer can be used. For example, the first block may be a homopolymer of one alkyl (meth) acrylate monomer, or a copolymer of a monomer mixture containing only two or more alkyl (meth) acrylate monomers, and other types The monomer may not be included. When the first block is formed by using a monomer such as styrene having a double bond between carbons, in addition to the alkyl (meth) acrylate, compatibility and phase separation between blocks are lowered, and thus it may be difficult to obtain sufficient durability or warpage prevention properties. .

In one example, the second block may include an alkyl (meth) acrylate monomer and a copolymerizable monomer having a crosslinkable functional group in a polymerized form. Specifically, the second block may include 80 to 99.9 parts by weight of an alkyl (meth) acrylate monomer and 0.1 to 20 parts by weight of a copolymerizable monomer having a crosslinkable functional group in a polymerized form. As the alkyl (meth) acrylate monomer for forming the second block, a monomer usable for forming the first block may be used.

In one example, an alkyl acrylate monomer may be used to form the second block. More specifically, the second block may include 80 to 99.9 parts by weight of an alkyl acrylate having an alkyl group having 1 to 4 carbon atoms, and 0.1 to 20 parts by weight of a copolymerizable monomer having a crosslinkable functional group in a polymerized form. When the second block satisfies the composition, it is possible to secure appropriate physical properties such as interfacial adhesion, durability, and proper cohesion.

The copolymerizable monomer having a crosslinkable functional group included in the second block, for example, has a site that can be copolymerized with other monomers included in the block copolymer, such as the alkyl acrylate monomer, and also the crosslinking described above. It may be a monomer having a sex functional group. As the crosslinkable functional group included in the copolymerizable monomer, the aforementioned hydroxy group, carboxyl group, epoxy group, isocyanate group or nitrogen-containing functional group can be used.

In one example, the copolymerizable monomer having a crosslinkable functional group may be a monomer having a hydroxy group. More specifically, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate or 8- Hydroxyalkyl (meth) acrylates such as hydroxyoctyl (meth) acrylate; Or hydroxyalkylene glycol (meth) acrylate, such as 2-hydroxyethylene glycol (meth) acrylate or 2-hydroxypropylene glycol (meth) acrylate; It may be a synthetic monomer, but is not limited thereto.

In one example, the block copolymer (A) 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. By adjusting the weight ratio between the first block and the second block as described above, it is possible to provide an adhesive composition and an adhesive having excellent physical properties.

In one example, the block copolymer (A) is a diblock copolymer including the first and second blocks (diblock copolymer), that is, a block air containing only two blocks of the first block and the second block It can be coalescence. For example, when a non-crosslinkable triblock copolymer is used, durability, reworkability, and warpage characteristics may be deteriorated. In consideration of the above points, the present application can maintain excellent interfacial adhesion, durability reliability, stress relaxation and reworkability of the pressure-sensitive adhesive by using a crosslinkable diblock copolymer.

The method for preparing the block copolymer (A) is not particularly limited, and a known method can be used. For example, the block polymer may be polymerized by LRP (Living Radical Polymerization). Specifically, using an organic rare earth metal complex as a polymerization initiator, or using an organic alkali metal compound as a polymerization initiator, anionic polymerization to synthesize in the presence of an inorganic acid salt such as an alkali metal or a salt of an alkaline earth metal, initiates polymerization of an organic alkali metal compound Anion polymerization method synthesized in the presence of an organoaluminum compound using zero, atomic transfer radical polymerization method (ATRP) using an atomic transfer radical polymerization agent as a polymerization control agent, and atomic transfer radical polymerization agent as a polymerization control agent but generating electrons Activators Regenerated by Electron Transfer (ARGET) atomic transfer radical polymerization (ATRP), Initiators for continuous activator regeneration (ICAR) atomic transfer radical polymerization (ATRP), reversibly adding-opening inorganic reducing agents Reversible addition-cleavage chain transfer with chain transfer agent Polymerization by (RAFT), or a method using an organic tellurium compound as an initiator may be used, and an appropriate method may be selected from the above methods to produce the block copolymer.

The pressure-sensitive adhesive layer of the present application may further include a random copolymer, for example, a non-crosslinkable random copolymer (B), in addition to the crosslinkable block copolymer (A). The non-crosslinkable random copolymer (B) may be an acrylic copolymer.

In the present application, "non-crosslinkable acrylic copolymer" may mean an acrylic polymer in which the crosslinkable block copolymer (A) does not contain a functional group capable of reacting with a crosslinking agent described below in a molecule. Since the non-crosslinkable acrylic copolymer (B) does not participate in a crosslinking reaction with a crosslinking agent, flexibility can be imparted to the crosslinking block copolymer and the crosslinking network by the crosslinking agent, thereby improving the anti-bending properties of the adhesive. You can.

In one example, the weight average molecular weight (Mw) of the non-crosslinkable acrylic copolymer (B) may range from 2,000 to 100,000. The non-crosslinkable acrylic copolymer having the molecular weight range, as well as providing flexibility to the pressure-sensitive adhesive, can minimize light leakage generated when exposed to high temperature or high temperature and high humidity conditions, and can also improve the durability of the pressure sensitive adhesive. When the weight-average molecular weight of the non-crosslinkable acrylic copolymer (B) is less than 2,000, there is a problem in that the heat and moisture resistance durability is lowered and the re-peelable adhesive remains in the adherend. Further, when the weight-average molecular weight of the non-crosslinkable acrylic copolymer (B) exceeds 100,000, it is difficult to suppress light leakage because the adhesive does not provide sufficient flexibility.

The non-crosslinkable acrylic copolymer (B) may have a glass transition temperature of less than 0 ° C. The lower limit of the glass transition temperature of the non-crosslinkable acrylic copolymer is not particularly limited, and may be, for example, -80 ° C or higher, -70 ° C or higher, or -60 ° C or higher.

When the molecular weight range and the glass transition temperature range are satisfied, the type of the monomer used to form the non-crosslinkable acrylic copolymer is not particularly limited. In one example, as the non-crosslinkable acrylic copolymer, an alkyl (meth) acrylate monomer used for forming the first block or the second block may be used. More specifically, an alkyl acrylate monomer having 4 or more carbon atoms, such as butyl acrylate or ethylhexyl acrylate, can be used to form a non-crosslinkable acrylic copolymer.

In one example, the non-crosslinkable random copolymer (B) may be included in an adhesive composition or an adhesive layer in an amount of 1 to 20 parts by weight compared to 100 parts by weight of the crosslinkable block copolymer (A). When the above content range is satisfied, it is possible to maintain excellent heat resistance or moisture heat resistance, and ensure excellent removability.

The pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer may include at least one crosslinking agent (C) capable of forming a chemical crosslinking structure by reacting with the crosslinkable functional group of the block copolymer. As the crosslinking agent, a multifunctional crosslinking agent having two or more functional groups capable of reacting with the crosslinkable functional group included in the block copolymer may be used. Non-limiting examples of such crosslinking agents include isocyanate crosslinking agents, epoxy crosslinking agents, aziridine crosslinking agents or metal chelate crosslinking agents.

In one example, when the crosslinkable functional group is a hydroxy group, an isocyanate crosslinking agent may be used as the multifunctional crosslinking agent. The type of the isocyanate crosslinking agent is not particularly limited, for example, tolylene diisocyanate, xylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isoboron diisocyanate, tetramethylxylene diisocyanate, or naphthalene diisocyanate. Diisocyanate compounds; Alternatively, a compound obtained by reacting the diisocyanate compound with a polyol may be used. Trimethylol propane may be used as the polyol.

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

The pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer may further include a silane coupling agent. For example, a silane coupling agent containing any one of an epoxy group, thiol group, amino group, vinyl group, epoxy group, beta-cyanoacetyl group, acetoacetyl group, or halogen may be used. More specifically, the silane coupling agent may be a compound having a beta-cyano group represented by the following formula (1), or a compound having an acetoacetyl group represented by the following formula (2).

[Formula 1]

(R ₁ ) _n Si (R ₂ ) _(4-n)

[Formula 2]

(R ₃ ) _n Si (R ₂ ) _(4-n)

In Formula 1 or 2, R ₁ is a beta-cyanoacetyl group or a beta-cyanoacetylalkyl group, R ₃ is an acetoacetyl group or acetoacetylalkyl group, R ₂ is an alkoxy group, and n is 1 to 3 Sue.

In Formula 1 or 2, the alkyl group may be an alkyl group having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms, and the alkyl group may be linear, branched or cyclic You 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 the alkoxy group is linear, branched or cyclic. It can be a prize.

Examples of the compound represented by Formula 1 or 2 include acetoacetylpropyl trimethoxy silane, acetoacetylpropyl triethoxy silane, beta cyanoacetylpropyl trimethoxy silane or beta cyanoacetylpropyl triethoxy silane, etc. However, it is not particularly limited thereto.

The silane coupling agent may be included in the range of 0.01 to 5 parts by weight compared to 100 parts by weight of the block copolymer (A). Specifically, it may be included in the composition in the range of 0.1 to 3 parts by weight relative to 100 parts by weight of the block copolymer.

The pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer, if necessary, may further include a tackifier. Examples of the tackifier include hydrocarbon resins or hydrogenated products thereof, rosin resins or hydrogenated products thereof, rosin ester resins or hydrogenated products thereof, terpene resins or hydrogenated products thereof, terpene phenol resins or hydrogenated products thereof, polymerized rosin resins, or Polymerized rosin ester resins, such as one or a mixture of two or more 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 for forming the pressure-sensitive adhesive layer may further include additives such as an epoxy resin, a curing agent, a UV 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 optical member of the present application may satisfy the condition of the following general formula (1). If the following conditions are not satisfied, it can be considered that the light leakage phenomenon of the polarizing plate or the display becomes severe because the degree of bending of the adhesive polarizing plate is large.

[Formula 1]

d <35 mm

In the general formula 1, d is, after storing the specimen attached to the adhesive optical member of 3.5 cm × 40.5 cm size to the glass, for 65 hours to 75 hours at 55 ℃ to 65 ℃ heating conditions, one end of the specimen Fixed and the other end represents the distance from the reference point. At this time, the thickness of the pressure-sensitive adhesive layer may be 15 μm to 25 μm.

In another example, the adhesive optical member of the present application has excellent removability. More specifically, since the adhesive-type optical member has a specific range of adhesive force, it can be removed from the adherend without residue upon re-release. For example, the adhesive optical member has a peeling force measured at a peeling angle of 180 ° and a peeling speed of 300 mm / min after attaching the adhesive optical member having a size of 25 mm × 100 mm to glass, 2,000 gf. / 25mm or less. If the value exceeds 2,000 gf / 25mm, the glass may be broken if the thickness of the glass is 0.7 t or less, and even if it is not broken, it can be considered that the re-removability is not good because residue remains in the adherend when peeling. The peeling force, after attaching the release substrate to PET on the end of the adhesive optical member attached to the glass, the specimen was left for 50 minutes to 120 minutes under heating conditions of 70 ℃ to 90 ℃, 18 ℃ to 25 ℃ It can be measured after 50 to 120 minutes storage at room temperature and a relative humidity of 55% to 65%. At this time, the thickness of the pressure-sensitive adhesive layer may be 15 μm to 25 μm.

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 adhesive optical member attached to one or both surfaces of the liquid crystal panel.

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 glass substrates. In this case, the optical member may be attached to the glass substrate via an adhesive layer.

The device may further include a light source on a side opposite to the viewer side of the liquid crystal panel. On the first substrate on the light source side, for example, an active driving circuit including a thin film transistor (TFT), a wiring, and the like as a driving element electrically connected to the transparent pixel electrode may be formed. The pixel electrode includes, for example, ITO (Indium Tin Oxide), 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.

As the liquid crystal panel in the device, for example, 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 panel such as a two-terminal or three-terminal type; All well-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, types of upper and lower substrates such as color filter substrates or array substrates in a liquid crystal display device are not particularly limited, and configurations known in this field can be employed without limitation.

The present application can provide an adhesive composition for an optical film capable of improving light leakage phenomenon as well as durability reliability under severe conditions such as high temperature and high humidity.

Hereinafter, the adhesive polarizing plate of the present application will be described in detail through examples and comparative examples. However, the scope of the present application is not limited by the following examples.

Physical properties in this example and comparative example were evaluated in the following manner.

1. Molecular weight evaluation

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

<GPC measurement conditions>

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

Column: 2 PL Mixed B connections

Column temperature: 40 ℃

Eluent: THF (Tetrahydrofuran)

Flow rate: 1.0 mL / min

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

2. Evaluation of glass transition temperature

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

<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. That is, in Formula A, the right side calculates the weight fraction of the used monomers by the glass transition temperature (Wn / Tn) divided by the monomers when the monomer forms a homopolymer, and then calculates the sum of the calculated values. to be.

3. Durability evaluation

The adhesive 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 19-inch commercial liquid crystal panel. Then, the panel to which the polarizing plate was attached was stored in an autoclave (50 ° C, 5 atmospheres) for about 20 minutes to prepare a sample.

The durability of the heat and moisture resistance of the prepared sample was evaluated by observing and evaluating the occurrence of bubbles and peeling at the adhesive interface according to the following criteria after the sample was left at 60 ° C and 90% relative humidity for 500 hours.

In the case of heat resistance durability, after the sample was left at 80 ° C. for 500 hours, the occurrence of bubbles and peeling was observed and evaluated according to the following criteria.

<Criteria for evaluating heat and moisture heat durability>

A: No bubbles and peeling occurred

B: Some bubbles and / or peeling occurred

C: A large amount of air bubbles and / or peeling occurred

4. Evaluation of bending properties

Prepare STN sodalime glass (4 x 41 cm ² , 0.4 t) for bending, use it as it is without washing if there is no foreign substance in the glass, or clean it using EAc and IPA solvent and then clean the air-gun And dried. The adhesive polarizing plates (coated products) prepared in Examples and Comparative Examples were prepared in a size of 3.5 cm × 40.5 cm so that the MD direction was long, and an adhesive polarizing plate was attached to the prepared bending glass using a laminator. Thereafter, a device capable of fixing the sample in the chamber was prepared as shown in the figure below, and after fixing one side of the glass to which the adhesive flat plate was attached, an initial value, that is, a curved separation distance from a reference point was measured. After measuring the initial value, after storing for 72 hours at 60 ° C. heat resistance, the separation distance from the reference point was measured again. Three samples were prepared for the same prescription, and the average distance was calculated.

<Measurement method of distance>

5. Removability  evaluation

The samples prepared by cutting the adhesive polarizing plates prepared in Examples and Comparative Examples to have a width of about 25 mm and a length of about 100 mm. After attaching the polarizer to the sodalime glass for STN, PET (100㎛) is attached to the end of the polarizer. After allowing it to stand for 60 minutes at 80 ℃, it is sufficiently cooled under constant temperature and humidity conditions (25 degrees, 60% relative humidity), and then subjected to a Peel test at a speed of 300 mm / min, and at an angle of 180 degrees, resulting in adhesion and residue on glass. The degree was confirmed.

Manufacturing example

Manufacturing example  One. Deblock  Preparation of copolymer (A1)

Ethyl 2-bromoisobutyrate (EBiB) 0.032g and methyl methacrylate (MMA) 11.4g and butyl methacrylate (BMA) 2.9g were mixed with ethyl acetate (EAc) 6.1g. The reactor containing the mixture was sealed, nitrogen purged and stirred 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 tris (2-pyridylmethyl) amine (TPMA) and 0.003 g of V-65 (2,2'-azobis (2,4-dimethyl valeronitrile)) were added to the oxygen-depleted mixture. Then, the reaction was initiated by immersion in a reaction tank at about 67 ° C (polymerization of the first block). At a time when the conversion rate of methyl methacrylate is about 70%, a mixture of 111.4 g of methyl acrylate (BA), 1.1 g of hydroxybutyl acrylate (HBA), and 75 g of ethyl acetate (EAc) previously bubbled with nitrogen It 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 chain extention reation was performed (polymerization of the second block). When the conversion rate of the monomer (BA) reaches 80% or more, the reaction mixture is exposed to oxygen and diluted in an appropriate solvent to terminate the reaction to terminate the P (MMA-BMA) -P (BA-HBA) diblock copolymer (A1) ). In the process, V-65 was appropriately divided and injected until the end of the reaction in consideration of its half-life.

Manufacturing example  2. Preparation of triblock copolymer (B1)

EBiB (ethyl 2-bromoisobutyrate) 0.5g, butyl acrylate (BA) 15.5g was mixed with ethyl acetate (EAc) 16g. The reactor containing the mixture was sealed, nitrogen purged and stirred at about 25 ° C. for about 30 minutes, and dissolved oxygen was removed through bubbling. Thereafter, a solution in which 0.002 g of CuBr2 and 0.006 g of TPMA (tris (2-pyridylmethyl) amine) was dissolved in 0.1 mL DMF (N, Ndimethylformamide) in which oxygen was removed was added to the mixture. Subsequently, 0.04 g of Sn (EH) 2 (tin (II) octoate) was added as a catalyst reducing agent to initiate the reaction. At a time when the monomer conversion was about 90%, 140 g of methyl methacrylate (MMA) and 140 g of EA, which had been deoxygenated in advance, were added, and nitrogen was bubbled for an additional 40 minutes to remove oxygen. When the temperature of the reactant reaches 65 degrees, a solution of 0.025 g of CuBr2 and 0.064 g of TPMA dissolved in 1.0 mL DMF (N, Ndimethylformamide) deoxygenated is added, followed by chain extension reaction by adding 0.49 g of Sn (EH) 2. Did. The PMMA-PBA-PMMA triblock copolymer (B1) was prepared by exposing the reaction mixture to oxygen when the conversion rate reached 80% or more, and diluting it in an appropriate solvent to terminate the reaction.

Manufacturing example  3 to 5. Preparation of block copolymers (A2, A3 and B2)

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

Block copolymer A1 A2 A3 B1 B2 Block 1 MMA ratio 80 70 60 100 - BMA ratio 20 30 40 - - Styrene - - - - 100 Tg (℃) 90 80 70 110 100 Mw (x10,000) 3 3.7 4.0 - 3.4 PDI 1.34 1.36 1.38 - 1.2 Block 2 BA ratio 99 99 99 100 99 HBA ratio One One One - One Tg (℃) -45 -45 -45 -45 -45 Mw (x10,000) - - - 3.5 - PDI - - - 1.35 - Block 3 MMA - - - 100 - Tg (℃) - - - 110 - Mw (x10,000) - - - - - PDI - - - - - block
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coalescence Block-to-block content 10:90 10:90 10:90 45:10:45 10:90 Mw (x10,000) 30.2 33.5 36.7 35.1 33.8 PDI 1.8 2.3 2.4 2.5 2.1 Ratio of monomer or block (content): parts by weight
BA: n-butyl acrylate (homopolymer Tg: about -45 ° C)
HBA: 4-hydroxybutyl acylate (homopolymer Tg: about -80 ℃)
MMA: methyl methacrylate (homopolymer Tg: about 110 ° C)
BMA: butyl methacrylate (homopolymer Tg: about 27 ℃)
Tg: glass transition temperature
Mw: weight average molecular weight
PDI: molecular weight distribution

Manufacturing example  6. Preparation of random copolymer (B3)

A mixture of monomers consisting of 99 parts by weight of n-butylacrylate (BA) and 1.0 part by weight of hydroxy butyl acrylate was introduced into a 1L reactor in which nitrogen gas was refluxed and a cooling device was installed to facilitate temperature control. . Then, 150 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 0.03 parts by weight of azobisisobutyronitrile (AIBN), a reaction initiator, was added and reacted for 8 hours to make it random. Copolymer (B3) was prepared. The prepared copolymer had a weight average molecular weight of 1.2 million and a molecular weight distribution of 5.1.

Manufacturing example  7. Preparation of random copolymer (C1)

100 parts by weight of toluene was added as a solvent to a 1L reactor in which nitrogen gas was refluxed and a cooling device was installed to facilitate temperature control. After purging nitrogen gas for 60 minutes to remove oxygen, the temperature was maintained at 110 ° C. 2 parts by weight of the reaction initiator azobisisobutyronitrile (AIBN) and 100 parts by weight of 100 parts by weight of n-butylacrylate (BA) purged with nitrogen gas for 60 minutes over a period of 4 hours It was put into the reactor and maintained at 110 ° C., and reacted for 1 hour after completion of the input to prepare a random copolymer (C1). The prepared copolymer had a weight average molecular weight of 12,000 and a molecular weight distribution of 2.1.

Manufacturing example  8. Preparation of random copolymer (C2)

100 parts by weight of toluene was added as a solvent to a 1L reactor in which nitrogen gas was refluxed and a cooling device was installed to facilitate temperature control. After purging nitrogen gas for 60 minutes to remove oxygen, the temperature was maintained at 95 ° C. 0.5 parts by weight of the reaction initiator azobisisobutyronitrile (AIBN) and 100 parts by weight of n-butylacrylate (BA) purged with nitrogen gas for 60 minutes were added over a period of 4 hours. It was put into the reactor and maintained at 95 ° C, and reacted for 1 hour after completion of the input to prepare a random copolymer (C2). The prepared polymer had a weight average molecular weight of 50,000 and a molecular weight distribution of 2.2.

Manufacturing example  9. Preparation of random copolymer (C3)

100 parts by weight of toluene was added as a solvent to a 1L reactor in which nitrogen gas was refluxed and a cooling device was installed to facilitate temperature control. After purging nitrogen gas for 60 minutes to remove oxygen, the temperature was maintained at 110 ° C. Reaction initiator azobisisobutyronitrile (AIBN) 2 parts by weight, chain transfer agent (CTA) 5 parts by weight and nitrogen gas purged (purging) for 60 minutes n-butylacrylate (n- 100 parts by weight of butylacrylate: BA) was added to the reactor over a period of 1 hour and maintained at 110 ° C, and reacted for 1 hour after completion of the injection to prepare a random copolymer (C3). The prepared random copolymer had a weight average molecular weight of 1,000 and a molecular weight distribution of 2.3.

Manufacturing example  10. Preparation of random copolymer (C4)

100 parts by weight of n-butylacrylate (BA) and 150 parts by weight of ethylacetate (EAc) as a solvent were added to a 1L reactor in which nitrogen gas was refluxed and a cooling device was installed to facilitate temperature control. After purging nitrogen gas for 60 minutes to remove oxygen, the temperature was maintained at 60 ° C., and 0.03 parts by weight of azobisisobutyronitrile (AIBN), a reaction initiator, was added and reacted for 8 hours to make it random. Copolymer (C4) was prepared. The prepared copolymer had a weight average molecular weight of 1,000,000 and a molecular weight distribution of 4.1.

Example  One.

Preparation of coating solution (adhesive composition)

With respect to 100 parts by weight of the block copolymer (A1) prepared in Preparation Example 1, 10 parts by weight of the non-crosslinkable acrylic copolymer (C1), 0.07 parts by weight of a crosslinking agent (Coronate L, manufactured by NPU, Japan), 0.1 parts by weight of DBTDL (Dibutyltin dilaurate) Part and 0.2 parts by weight of a silane coupling agent having a beta cyanoacetyl group were mixed, and ethyl acetate was blended as a solvent to adjust the coating solid content to about 30% by weight to prepare a coating solution (adhesive composition).

Preparation of adhesive polarizing plate

The prepared coating solution was coated on a release surface of release PET (poly (ethylene terephthalate)) (MRF-38, manufactured by Mitsubishi) having a thickness of 38 μm, which was molded so that the thickness after drying would be about 23 μm, and then dried in an oven at 110 ° C. Hold for 3 minutes. After drying, a polarizing plate (COP / PVA / COP layered structure: COP = cyclopolyolefin, PVA = polyvinyl alcohol-based polarizing film) was laminated on one side of the coating layer formed on release PET to prepare an adhesive polarizing plate.

Example  2 to 4 and Comparative example  1 to 8

An adhesive composition (coating solution) and an 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 when preparing the adhesive composition (coating solution).

Example Comparative example One 2 3 4 5 One 2 3 4 5 6 7 8 block
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coalescence Kinds A1 A2 A3 A1 A1 A1 A1 A1 A1 B1 B2 B3 A1 content 100 100 100 100 100 100 100 100 100 100 100 100 100 random
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coalescence Kinds C1 C1 C1 C1 C2 C1 C1 C3 C4 C1 C1 C1 B3 content 10 10 10 20 10 0.1 50 10 10 10 10 10 10 Crosslinker
content 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 0.07 DBTDL
content 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 SCA
content 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Content unit: parts by weight
Crosslinking agent: Coronate L, made in Japan NPU
DBTDL: Dibutyltin dilaurate
SCA: Silane coupling agent having β-cyanoacetyl group (M812, manufactured by LG Chemical)

Table 3 below shows the evaluation results of the physical properties of the Examples and Comparative Examples.

Example Comparative example One 2 3 4 5 One 2 3 4 5 6 7 8 Heat resistant durability A A A A A B C C C C B C B Moist heat  durability A A A A A B C C C C C C B 휜 distance
(mm) 33 31 29 25 34 39 23 38 41 40 39 46 58 Jail Lee Sung adhesiveness
( gf / 25mm) 1500 1600 1700 1650 1620 1400 2300 4100 3200 2400 1900 1600 1500 Residue
( U: O , Nothing: x) X X X X X X O O O O X X X

As shown in Tables 2 and 3, Examples 1 to 5 have excellent durability, anti-bending properties, and removability, but the contents of the non-crosslinkable random copolymer are different from those of the present application as in Comparative Examples 1 and 2. In the case of Comparative Examples 3 and 4, when the molecular weight of the non-crosslinkable random copolymer is different from the present application, it can be seen that the durability and the anti-bending properties are poor. In addition, Comparative Example 5 using a triblock copolymer, Comparative Example 6 in which a monomer different from the acrylic monomer was used in the first block, Comparative Example 7, in which a random copolymer was used instead of the block copolymer, and a crosslinkable random copolymer of high molecular weight Also, Comparative Example 8 in which coalescence was used, it can be seen that the durability and the anti-bending properties are poor as compared with the present application.

Claims (16)

Polarizing film; And
It is provided on at least one surface of the polarizing film, a crosslinkable block copolymer (A); Non-crosslinkable random copolymer (B); And an adhesive layer (B) formed of an adhesive composition comprising a silane coupling agent,
The non-crosslinkable random copolymer (B) has a weight average molecular weight (Mw) of 2,000 to 100,000, a glass transition temperature of less than 0 ° C,
The crosslinkable block copolymer (A) containing 1 to 20 parts by weight of the non-crosslinkable random copolymer (B) compared to 100 parts by weight of the adhesive polarizing plate. The crosslinkable block copolymer (A) according to claim 1,
An adhesive polarizing plate having a first block having a glass transition temperature of 50 ° C or higher and a second block having a glass transition temperature of -10 ° C or lower. The adhesive polarizing plate of claim 2, wherein the crosslinkable block copolymer (A) has a weight average molecular weight (Mw) of 100,000 or more. The adhesive polarizing plate according to claim 2, wherein the crosslinkable block copolymer (A) has a crosslinkable functional group in the second block. The adhesive polarizing plate of claim 2, wherein the first block is a polymer of an alkyl (meth) acrylate monomer. The adhesive polarizing plate of claim 5, wherein the first block has a weight average molecular weight (Mw) of 10,000 to 50,000. The adhesive polarizing plate of claim 2, wherein the second block comprises 80 to 99.9 parts by weight of an alkyl (meth) acrylate monomer and 0.1 to 20 parts by weight of a copolymerizable monomer having a crosslinkable functional group in a polymerized form. The adhesive polarizing plate according to claim 7, wherein the crosslinkable functional group is a hydroxy group, a carboxyl group, an epoxy group, an isocyanate group or a nitrogen-containing functional group. The adhesive polarizing plate of claim 2, wherein the block copolymer (A) comprises 5 to 50 parts by weight of the first block and 50 to 95 parts by weight of the second block. The adhesive polarizing plate according to claim 9, wherein the block copolymer (A) is a diblock copolymer composed of the first block and the second block. The adhesive polarizing plate according to claim 1, wherein the non-crosslinkable random copolymer (B) is a polymer of an alkyl (meth) acrylate monomer. delete According to claim 1, Compared to 100 parts by weight of the block copolymer (A), the adhesive polarizing plate comprising a multifunctional crosslinking agent (C) in the range of 0.01 to 10 parts by weight. delete The adhesive polarizing plate according to claim 1, which satisfies the following general formula 1:
[Formula 1]
d <35 mm
In the general formula 1, d is a specimen with a 3.5 cm × 40.5 cm sized adhesive optical member attached to glass, stored at 55 ° C. to 65 ° C. for 65 hours to 75 hours, and fixed at one end of the sample And the other end represents the distance from the reference point. A display device comprising a liquid crystal panel in which the adhesive polarizing plate according to claim 1 is attached to one side or both sides.