KR20180122186A - Pressure-sensitive adhesive - Google Patents

Abstract

The present application relates to an adhesive composition and a polarizing plate including the same. The adhesive composition may selectively adjust a hard type and a soft type according to use and have excellent in holding power under severe conditions. The composition includes a monomer component including a compound represented by a chemical formula 1 or a polymer component having the monomer component as a polymerization unit.

Description

[0001] PRESSURE-SENSITIVE ADHESIVE [0002]

The present application relates to a pressure-sensitive adhesive composition and a polarizing plate comprising the same.

2. Description of the Related Art A liquid crystal display (LCD) is a display device that is used in various fields because it has advantages such that power consumption is low and it can be made thinner in a plane.

A liquid crystal display device includes: a liquid crystal panel including a liquid crystal existing between transparent substrates; And a polarizing plate attached to both sides of the liquid crystal panel. The polarizer is adhered by a pressure sensitive adhesive. At this time, productivity and environmental safety problems may occur due to the solvent present in the pressure sensitive adhesive. Further, there is a problem that heat wrinkles and coating lines are generated when the pressure sensitive adhesive is thermally cured. There is a problem in terms of the holding force of the pressure-sensitive adhesive in a display or a curved display.

Accordingly, a solution to the above problem is required.

The present invention relates to a pressure-sensitive adhesive for a polarizing plate, which can selectively control a hard type and a soft type according to a use, and provides a pressure-sensitive adhesive composition excellent in holding power under severe conditions.

The present application relates to a pressure-sensitive adhesive composition. The pressure-sensitive adhesive composition may be applied to one side of the polarizer. Specifically, the pressure-sensitive adhesive composition may be adhered to one surface of the polarizer in a cured state, and may be used for adhering a polarizing plate to a liquid crystal panel.

Exemplary pressure-sensitive adhesive compositions may comprise a monomer component comprising a compound represented by the following formula (1) or a polymer component having the monomer component as a polymerization unit. The pressure-sensitive adhesive composition may comprise the monomer component and / or a mixture of the polymer components. In the above, the monomer component or the polymer component may form a partial polymer. On the other hand, the mixture may be a photocurable composition, and the mixture may form a photocurable syrup. By providing the above-mentioned composition, the present invention can suppress heat wrinkles and coating lines that are generated during thermal curing, and can reduce the productivity and environmental safety problems caused by the solvent. In addition, the present application can maintain excellent retention of the pressure-sensitive adhesive under severe conditions by containing the following formula (1) as a monomer component or a polymerization unit.

[Chemical Formula 1]

Wherein R ₁ is hydrogen or an alkyl group, X ₁ and X ₂ are each independently oxygen or a single bond, A is an alkylene group, an alkylidene group or a single bond, R ₂ to R ₆ are each independently Hydrogen, an alkyl group or Q, each of R ₇ to R ₁₁ is independently hydrogen or an alkyl group, and Q is a single bond, an alkylene group, an alkylidene group or a carbonyl group.

In Formula 1, Q may be connected to the center of the left benzene ring to mean that at least one of R ₂ to R ₆ is Q. For example, when R < ₄ > is Q, Q may be connected to R < ₄ > to mean that two benzene rings are connected by Q.

In the embodiments of the present application, the pressure-sensitive adhesive composition may be capable of primary crosslinking by light containing one of the wavelengths in the UV region and secondary crosslinking by light having a wavelength lower than that during the primary crosslinking. When the primary crosslinking and the secondary crosslinking are carried out together, the crosslinking sequence is not particularly limited. The secondary crosslinking light may have a wavelength range of, for example, from 260 nm to 330 nm, from 268 nm to 329 nm, from 277 nm to 316 nm, from 283 nm to 309 nm, or from 294 nm to 305 nm. In addition, the primary crosslinking light may have a wavelength range of, for example, 330 nm to 380 nm, 331 nm to 372 nm, 342 nm to 369 nm, and 353 nm to 367 nm. In the present application, the pressure-sensitive adhesive by the primary crosslinking can be used as a soft type pressure-sensitive adhesive, and when proceeding to primary and secondary crosslinking, a pressure-sensitive adhesive can be used in a hard type. Accordingly, the modulus of elasticity of the pressure-sensitive adhesive which has undergone only the primary crosslinking can be lower than that of the pressure-sensitive adhesive which has progressed to the primary and secondary crosslinks. In the primary crosslinking, the ultraviolet range may be conventional UV curable wavelength range. However, although the wavelength range in the secondary crosslinking is in the ultraviolet range, the conventional ultraviolet curing type pressure-sensitive adhesive has remarkably decreased the degree of crosslinking at a wavelength of 330 nm or less. However, the present invention provides a composition capable of achieving the desired crosslinking even in the case of light having a wavelength of 330 nm or less. Accordingly, the pressure-sensitive adhesive composition of the present application can be used as desired if desired, by proceeding only with primary crosslinking, or by conducting primary and secondary crosslinking.

In one example, the compound of Formula 1 includes a benzophenone-based compound such as benzophenone methacrylate (BPMA), 6- (4-benzoylphenoxy) hexyl (meth) acrylate or benzophenone acrylate can do. .

In the specific embodiment of the present invention, the compound represented by Formula 1 is contained in an amount of 0.01 to 10 parts by weight, 0.015 to 7 parts by weight, 0.1 to 6 parts by weight, or 0.15 to 3 parts by weight based on 100 parts by weight of the monomer component or the polymer component . In the present application, when the pressure-sensitive adhesive composition is cured and applied to a polarizer by controlling the content ratio, the adhesive retention force can be realized under severe conditions such as high temperature and high humidity conditions or physical conditions such as warpage.

As used herein, the term " single bond " means a bond that links an atom and an atom without a separate atom. For example, when A is a single bond, the X ₁ atom and the X ₂ atom in formula (1) may be directly connected. At this time, when X ₂ atom is also a single bond, X ₁ atom can be directly connected to the benzene ring. When Q in Formula (1) is a single bond, two benzene rings may be directly connected to each other.

The term "alkyl group" as used herein means an alkyl group having 1 to 30 carbon atoms, 1 to 25 carbon atoms, 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 ≪ / RTI > The alkyl group may have a linear, branched or cyclic structure and may optionally be substituted with one or more substituents.

Unless otherwise specified, the term "alkylene group" or "alkylidene group" as used herein may mean an alkylene group or an alkylidene group having 1 to 12 carbon atoms, 4 to 10 carbon atoms, or 6 to 9 carbon atoms . The alkylene group or alkylidene group may be linear, branched or cyclic. Also, the alkylene group or alkylidene group may be optionally substituted with one or more substituents.

As used herein, the term " aryl group " means a monovalent residue derived from a compound or a derivative thereof containing a structure containing benzene or two or more benzenes condensed or bonded, unless otherwise specified have. The aryl group may be, for example, an aryl group having 6 to 22 carbon atoms, 6 to 16 carbon atoms, or 6 to 13 carbon atoms, and examples thereof include phenyl, phenylethyl, phenylpropyl, benzyl, tolyl, An xylyl group or a naphthyl group.

Examples of the substituent which may be substituted in the specific functional group in the present invention include a halogen atom, a hydroxyl group, a carboxyl group, a thiol group, an alkyl group, an alkoxy group, an alkenyl group, an epoxy group, a cyano group, a carboxyl group, an acryloyl group, , An acryloyloxy group, a methacryloyloxy group, or an aryl group, but the present invention is not limited thereto.

In one example of the present application, the monomer component may comprise a (meth) acrylic acid ester-based monomer. The (meth) acrylic acid ester monomer may be present as a monomer component in the pressure-sensitive adhesive composition, or may be present as polymerized units of the polymer. In one example, the pressure-sensitive adhesive composition comprises 50 to 99.9 parts by weight and 0.1 to 8 parts by weight of a (meth) acrylic acid ester-based monomer and a compound represented by the formula (1), respectively; 58 to 95 parts by weight and 0.15 to 5 parts by weight; Or 67 to 88 parts by weight and 0.18 to 2 parts by weight. The present application can be applied to a polarizer to suppress the shrinkage or expansion of the polarizer and inhibit delamination between layers by including the weight ratio of the above-mentioned formula (1) and the (meth) acrylic acid ester monomer within the above range to provide a highly reliable polarizing plate .

As used herein, the term " parts by weight "

In one example, the (meth) acrylic acid ester-based monomer may be an alkyl (meth) acrylate having a linear, branched or cyclic alkyl group. The alkyl (meth) acrylate may be an alkyl (meth) acrylate having an alkyl group having 1 to 14 carbon atoms in consideration of physical properties such as cohesion, glass transition temperature and tackiness. Examples of such alkyl (meth) acrylates include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (Meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, Acrylate, lauryl (meth) acrylate, and tetradecyl (meth) acrylate. One or more of these may be contained in a polymerized form in the resin.

In one example, the monomer component may further comprise a compound represented by the following formula (2).

(2)

R ₁ is hydrogen or an alkyl group, X and Z are each independently an alkylene group or an alkylidene group, n is a number of 0 to 5, and R ₁₄ is an alkyl group or an aryl group.

Examples of the above-mentioned Formula 2 include, but are not limited to, 2-methoxyethyl acrylate or 2- (2-ethoxyethoxy) ethyl (meth) acrylate. In the present application, the durability reliability of the pressure-sensitive adhesive can be improved by controlling the weight ratio of the compound of Formula 2 to the above range.

In one example, the monomer component may further comprise a compound represented by the following formula (3).

(3)

In Formula 3, R ₁ is hydrogen or an alkyl group, A and T are each independently an alkylene group or an alkylidene group, and n is a number of 0 to 5.

In formula (3), n may be more preferably 0 to 3, and still more preferably 0 to 2. Examples of the compound of the formula (3) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (Meth) acrylate, 2-hydroxyethyleneglycol (meth) acrylate or 2-hydroxypropyleneglycol (meth) acrylate, but are not limited thereto.

In one example, the compound represented by Formula 2 may be contained in an amount of 5 to 25 parts by weight, 9 to 23 parts by weight, 9.5 to 18 parts by weight, or 10 to 15 parts by weight based on 100 parts by weight of the monomer component or the polymer component. In one example, the compound represented by Formula 3 may be contained in an amount of 5 to 25 parts by weight, 9 to 23 parts by weight, 9.5 to 18 parts by weight, or 10 to 15 parts by weight based on 100 parts by weight of the monomer component or the polymer component have. The compound represented by Formula 2 and / or Formula 3 may be contained in an amount of 5 to 50 parts by weight, 9 to 44 parts by weight, 11 to 38 parts by weight or 17 to 27 parts by weight based on 100 parts by weight of the monomer component or the polymer component have. The present application can improve retention and durability against external stress by adjusting the weight ratios of the compounds of the formulas (2) and (3) to the above ranges.

In one example, the monomer component may further comprise a compound represented by the following formula (4).

[Chemical Formula 4]

In Formula 4, R ₁ is hydrogen or an alkyl group, and U is a monovalent residue derived from an aliphatic saturated hydrocarbon cyclic compound.

The monovalent residue in the above formula (4) may mean a monovalent residue derived from an aliphatic saturated hydrocarbon cyclic compound, specifically, a compound in which carbon atoms are bonded in a ring form, which is not an aromatic compound, or a derivative of the compound . The aliphatic saturated hydrocarbon cyclic compound may be an aliphatic saturated hydrocarbon cyclic compound having 3 to 20 carbon atoms, preferably 6 to 15 carbon atoms, more preferably 8 to 12 carbon atoms. Examples of the monovalent residue include an isobornyl group, a cyclohexyl group, a norbornanyl group, a norbornenyl group, a dicyclopentadienyl group, an ethynylcyclohexane group, an ethynylcyclohexene group, Ethynyldecahydronaphthalene group, and the like can be exemplified. In one example, an isoboronyl group may be used, but the present invention is not limited thereto.

In one example, the compound represented by the general formula (4) may be contained in an amount of 1 to 15 parts by weight, 2 to 14 parts by weight, 3 to 13 parts by weight or 4 to 12 parts by weight based on 100 parts by weight of the monomer component or the polymer component. If the proportion of the compound of the general formula (4) in the monomer component is excessively low, the durability can not be secured effectively. If the proportion is too high, the tackiness of the pressure-sensitive adhesive may be deteriorated.

The monomer or polymer component may be a component that forms the base of the pressure-sensitive adhesive after being cured. The term " hardening " may mean a process in which the adhesive composition exhibits adhesive performance by physical or chemical action or reaction of the components contained in the adhesive composition.

The monomer or polymer component may be present in various forms, as long as it contains the components as described above and can also exhibit adhesive properties when cured.

In one example, if the composition is a thermosetting type, the monomer or polymer component may be an acrylic polymer having the monomer component as a polymerization unit. The acrylic polymer may be a crosslinkable acrylic polymer containing, as polymerized units, a copolymerizable monomer which provides a crosslinkable functional group known in the adhesive resin field. In addition, in the above case, the pressure-sensitive adhesive composition may further comprise a multifunctional crosslinking agent capable of crosslinking the polymer. As the polyfunctional crosslinking agent, for example, known crosslinking agents such as an isocyanate crosslinking agent, an epoxy crosslinking agent, an aziridine crosslinking agent and a metal chelate crosslinking agent may be used. The ratio of the cross-linking agent in the composition is not particularly limited and can be appropriately adjusted in consideration of the desired cohesive force.

The pressure-sensitive adhesive composition may be of a photocurable type. The term " photocurable adhesive composition " may refer to a composition that can be cured by irradiation of electromagnetic waves to be converted to a pressure sensitive adhesive. The electromagnetic waves may include microwaves, infrared (IR), ultraviolet (UV), X-rays, gamma rays or alpha-particle beams, proton beams, neutron beams, electron beams, and the like, and ultraviolet rays or electron beams may be used.

If the pressure-sensitive adhesive composition is a photo-curable type, the monomer or polymer component may comprise a photocurable oligomer and a reactive diluting monomer. Examples of photocurable oligomers may include all oligomer components used in the manufacture of photocurable pressure sensitive adhesive compositions such as UV curable. For example, the oligomer may be a urethane acrylate such as a reaction product of a polyisocyanate having two or more isocyanate groups in the molecule and a hydroxyalkyl (meth) acrylate; Ester type acrylates such as a polyester polyol and a dehydration condensation reaction product of (meth) acrylic acid; Ester-based urethane acrylates obtained by reacting an ester-based urethane resin, which is a reaction product of a polyester polyol and a polyisocyanate, with a hydroxyalkyl acrylate compound; Ether-based acrylates such as polyalkylene glycol di (meth) acrylate and the like; Ether-based urethane acrylate obtained by reacting an ether-based urethane resin, which is a reaction product of a polyether polyol and a polyisocyanate, with a hydroxyalkyl (meth) acrylate; Or an epoxy acrylate such as an addition reaction product of an epoxy resin and (meth) acrylic acid, but the present invention is not limited thereto.

In one example, the pressure sensitive adhesive composition of the present application may be a composition that is simultaneously thermoset and photopolymerizable. In this case, a photoinitiator and a thermosetting multifunctional crosslinking agent may be included together. The present application relates to a polyfunctional acrylate which is capable of UV crosslinking by a polyfunctional acrylate described later and a photoinitiator and / or a monomer component described above, and the present application also includes a multifunctional crosslinking agent which is thermally curable at the same time to improve adhesion to an adherend . Further, the present application can proceed with further crosslinking by irradiating light in the aforementioned low wavelength range.

As the reactive diluting monomer in the composition of the above type, the compounds represented by the above formulas (1) to (4) or (meth) acrylic acid may be used. As the reactive monomer, other monomers known in the art may be used as monomers having reactive functional groups such as (meth) acryloyl groups in addition to the above. Examples of the other monomer include alkyl (meth) acrylate; Aryl group-containing monomers such as benzyl (meth) acrylate or phenoxyethyl (meth) acrylate; Monomers containing a heterocyclic residue such as tetrahydrofurfuryl (meth) acrylate or (meth) acryloyl morpholine; and the like; Or polyfunctional acrylates, but are not limited thereto.

The pressure-sensitive adhesive composition may, if necessary, contain a polyfunctional acrylate together with the above-mentioned components. The multifunctional acrylate can be preferably included, but is not limited to, especially when the monomer or polymer component is a photo-curable syrup of the above-described non-solvent type. Examples of the polyfunctional acrylate include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, polyethylene glycol Di (meth) acrylate, neopentylglycol adipate di (meth) acrylate, hydroxyl puivalic acid neopentyl glycol di (meth) acrylate, dicyclopentanyl di (Meth) acrylate, caprolactone modified dicyclopentenyl di (meth) acrylate, ethylene oxide modified di (meth) acrylate, di (meth) acryloxyethyl isocyanurate, allyl cyclohexyl di (Meth) acrylate, tricyclodecane dimethanol (meth) acrylate, dimethylol dicyclopentanedi (meth) acrylate, ethylene oxide modified hexahydrophthalic acid di (meth) (Meth) acrylates such as cyclodecane dimethanol (meth) acrylate, neopentyl glycol-modified trimethylpropane di (meth) acrylate, adamantane di (meth) acrylate or 9,9-bis [4- Oxy] ethoxy) phenyl] fluorene and the like; (Meth) acrylates such as trimethylolpropane tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri Trifunctional acrylates such as modified trimethylolpropane tri (meth) acrylate, trifunctional urethane (meth) acrylate or tris (meth) acryloxyethylisocyanurate; Tetrafunctional acrylates such as diglycerin tetra (meth) acrylate or pentaerythritol tetra (meth) acrylate; Pentafunctional acrylates such as propionic acid-modified dipentaerythritol penta (meth) acrylate; And dipentaerythritol hexa (meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) acrylate or urethane (meth) acrylate (e.g., an isocyanate monomer and trimethylolpropane tri A hexafunctional acrylate such as a reaction product, and the like, but the present invention is not limited thereto.

The multifunctional acrylate may be included in an amount of 0.05 to 50 parts by weight, 0.06 to 35 parts by weight, 0.07 to 24 parts by weight, 0.08 to 18 parts by weight, or 0.09 to 9 parts by weight, based on 100 parts by weight of the monomer or polymer component However, this can be changed in consideration of process efficiency, physical properties of the pressure-sensitive adhesive, and the like.

In one example, the adhesive composition may further comprise a photoinitiator. The degree of polymerization can be controlled according to the amount of photoinitiator used. As the photoinitiator, any photoinitiator can be used as long as it can initiate the polymerization reaction through light irradiation or the like. Examples of the photoinitiator include alpha-hydroxyketone compounds (e.g., IRGACURE 184, IRGACURE 500, IRGACURE 2959, DAROCUR 1173, Ciba Specialty Chemicals); Phenylglyoxylate-based compounds (ex IRGACURE 754, DAROCUR MBF; Ciba Specialty Chemicals); Benzyldimethylketal compounds (ex IRGACURE 651; Ciba Specialty Chemicals); a-aminoketone-based compounds (ex IRGACURE 369, IRGACURE 907, IRGACURE 1300, Ciba Specialty Chemicals); Monoacylphosphine based compounds (MAPO) (ex. DAROCUR TPO; Ciba Specialty Chemicals); Bisacylphosphine compounds (BAPO) (ex IRGACURE 819, IRGACURE 819DW; Ciba Specialty Chemicals); Phosphine oxide-based compounds (ex IRGACURE 2100; Ciba Specialty Chemicals); Metallocene compounds (ex IRGACURE 784; Ciba Specialty Chemicals); Iodonium salt (ex IRGACURE 250 from Ciba Specialty Chemicals); And mixtures of one or more of the above (e.g., DAROCUR 4265, IRGACURE 2022, IRGACURE 1300, IRGACURE 2005, IRGACURE 2010, IRGACURE 2020, Ciba Specialty Chemicals). The pressure-sensitive adhesive composition may include, but is not limited to, one or more of the above.

The photoinitiator may be included in the composition in an amount of 0.05 to 20 parts by weight based on 100 parts by weight of the monomer or polymer component, but may be changed in consideration of process efficiency and physical properties of the cured product.

Further, in the present application, the pressure-sensitive adhesive composition may include a polyfunctional crosslinking agent. Such a crosslinking agent improves the cohesive force of the resin cured product (pressure-sensitive adhesive) through the reaction with the polar functional group contained in the acrylic polymer, And plays a role of controlling the adhesive property.

In one example, the polyfunctional crosslinking agent may be at least one selected from the group consisting of an isocyanate compound, an epoxy compound, an aziridine compound, and a metal chelate compound, and the polymer of the present application may be crosslinked by the polyfunctional crosslinking agent. In the present application, one kind or two or more kinds of cross-linking agents may be appropriately selected in consideration of the kind of reactive functional groups contained in the polymer.

Examples of the isocyanate crosslinking agent include tolylene diisocyanate, xylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, tetramethylxylene diisocyanate, and naphthalene diisocyanate, Addition reaction product of an isocyanate compound and a polyol may be used. As the polyol, trimethylolpropane or the like may be used. Examples of the epoxy crosslinking agent include ethylene glycol diglycidyl ether, triglycidyl ether, trimethylol propane triglycidyl ether, N, N, N ', N'-tetraglycidylethylenediamine or glycerin diglycidyl Ether and the like can be used. As the aziridine crosslinking agent, N, N'-toluene-2,4-bis (1-aziridine carboxamide), N, N'-diphenylmethane- , 4'-bis (1-aziridine carboxamide), triethylene melamine, bisisopropanoyl-1- (2-methylaziridine) or tri-1-aziridinylphosphine oxide But is not limited thereto. Examples of the metal chelate crosslinking agent include compounds in which a polyvalent metal such as aluminum, iron, zinc, tin, titanium, antimony, magnesium and / or vanadium is coordinated to acetylacetone or ethyl acetate or the like. But is not limited to.

Further, in one example, the polyfunctional crosslinking agent may be a mixture of aliphatic linear polyvalent NCO and aliphatic cyclic polyvalent NCO. For example, the aliphatic linear polyvalent NCO may be hexamethylene diisocyanate, and the aliphatic cyclic polyvalent NCO may be isoboron diisocyanate. The aliphatic linear polyvalent NCO and the aliphatic cyclic polyvalent NCO may be mixed in a weight ratio of 6: 4 to 9: 1 to form a mixture, and the mixture may contain 8 to 20% by weight of NCO. On the other hand, in the present specification, the NCO may mean an isocyanate group.

The multifunctional crosslinking agent may be contained in an amount of 0.01 to 10 parts by weight, 0.1 to 9 parts by weight, or 0.2 to 8 parts by weight based on 100 parts by weight of the monomer component or the polymer component.

The present application also relates to a polarizing plate. The polarizing plate may include a polarizer and a pressure-sensitive adhesive layer formed on one surface of the polarizer, wherein the pressure-sensitive adhesive composition described above is contained in a cured state.

A polarizer is a functional film or sheet capable of extracting only light vibrating in one direction from incident light while vibrating in various directions. As the polarizer, for example, a conventional polarizer such as a polyvinyl alcohol polarizer can be used. Such a polarizer may be a form in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol-based resin film. The polyvinyl alcohol-based resin constituting the polarizer can be obtained by, for example, gelling a polyvinyl acetate-based resin. Examples of the polyvinyl acetate-based resin include homopolymers of vinyl acetate; And copolymers of vinyl acetate and other monomers copolymerizable therewith. Examples of the monomer copolymerizable with vinyl acetate include, but are not limited to, one or more kinds of monomers such as unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having an ammonium group. The degree of gelation of the polyvinyl alcohol-based resin may be generally from 85 mol% to 100 mol%, preferably 98 mol% or more. The polyvinyl alcohol resin may be further modified. For example, polyvinyl formal or polyvinyl acetal modified with aldehyde may be used. The degree of polymerization of the polyvinyl alcohol-based resin may be about 1,000 to 10,000, preferably about 1,500 to 5,000.

The present application provides a pressure-sensitive adhesive composition which is capable of selectively controlling a hard type and a soft type according to a use and has excellent holding power under severe conditions.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the scope of the present application is not limited by the following examples.

Example  One

70 parts by weight of 2-ethylhexyl acrylate, 10 parts by weight of isobornyl acrylate, 10 parts by weight of 4-hydroxybutyl acrylate, 10 parts by weight of 2-methoxyethyl acrylate and 0.2 parts by weight of benzophenone methacrylate A monomer mixture was prepared. To the monomer mixture, an appropriate amount of EHPDC (EHPDC, di (2-ethylhexyl) peroxydicarbonate) was added as an initiator and bulk polymerization was conducted to prepare a photocurable syrup. 0.3 parts by weight of a photoinitiator (2,4,6-trimethylbenzoyl diphenyl phosphone (TPO), 0.1 part by weight of 1,6-hexanediol diacrylate (HDDA), 0.2 part by weight of a coupling agent, And 0.1 part by weight of a thermosetting agent (TKA-100) were blended to prepare a pressure-sensitive adhesive composition. The prepared pressure-sensitive adhesive composition was applied to a silicone release PET sheet, and the distance between the black light source in the wavelength range of 365 nm and the layer of the applied pressure-sensitive adhesive composition was maintained at 15 cm. And an ultraviolet ray was irradiated for 5 minutes to prepare a pressure-sensitive adhesive layer having a thickness of 25 占 퐉. The pressure-sensitive adhesive layer was attached to one surface of a polyvinyl alcohol polarizer formed on both sides of a protective film to prepare a polarizing plate.

Example  2

A pressure-sensitive adhesive layer and a polarizing plate were prepared in the same manner as in Example 1, except that the photoinitiator was changed to Irgacure 819.

Example  3

A pressure-sensitive adhesive layer and a polarizing plate were prepared in the same manner as in Example 1, except that the photoinitiator was changed to Irgacure 651.

Example  4

The pressure-sensitive adhesive layer of Example 1 was irradiated with ultraviolet rays at 2000 mJ / cm ² through a metal halide light source in a ^{second order} to produce a pressure-sensitive adhesive layer and a polarizing plate.

Example  5

The pressure-sensitive adhesive layer of Example 2 was irradiated with ultraviolet rays at 2000 mJ / cm ² through a metal halide light source in a ^{second order} to produce a pressure-sensitive adhesive layer and a polarizing plate.

Example  6

The pressure-sensitive adhesive layer of Example 3 was irradiated with ultraviolet rays at 2000 mJ / cm ² through a metal halide light source in a ^{second order} to produce a pressure-sensitive adhesive layer and a polarizing plate.

Comparative Example  One

99 parts by weight of n-butyl acrylate and 1 part by weight of 4-hydroxybutyl acrylate were compounded to prepare a monomer mixture. To the monomer mixture, an appropriate amount of EHPDC (EHPDC, di (2-ethylhexyl) peroxydicarbonate) was added as an initiator and bulk polymerization was conducted to prepare a photocurable syrup. 0.3 parts by weight of a photoinitiator (2,4,6-trimethylbenzoyl diphenyl phosphone (TPO)) and 0.1 part by weight of 1,6-hexanediol diacrylate (HDDA) were added to 100 parts by weight of the monomer component to prepare a pressure-sensitive adhesive composition. The prepared pressure-sensitive adhesive composition was applied to a PET sheet and ultraviolet rays were irradiated to the PET sheet for about 5 minutes while the distance between the black light source and the applied pressure-sensitive adhesive composition layer was kept at 15 cm, A pressure-sensitive adhesive layer having a thickness of 25 m was prepared. The pressure-sensitive adhesive layer was attached to one surface of a polyvinyl alcohol polarizer formed on both sides of a protective film to prepare a polarizing plate.

Comparative Example  2

A solvent was added in the same monomer composition as in Comparative Example 1 to prepare a thermosetting resin composition. 0.1 part by weight of TKA-100 as a thermosetting agent was further added to 100 parts by weight of the resin composition, followed by curing at 110 DEG C for 3 minutes to prepare a pressure-sensitive adhesive layer. The pressure-sensitive adhesive layer was attached to one surface of a polyvinyl alcohol polarizer formed on both sides of a protective film to prepare a polarizing plate.

Experimental Example  One - Pushed distance  Creep test

When the pressure sensitive adhesive layer of the polarizing plate according to the Examples and Comparative Examples was adhered to a glass plate at an adhesion area of 1 cm x 1 cm and after 24 hours at room temperature, when a load of 1 kg / The pushing distance of the pressure-sensitive adhesive layer is measured.

Pushing distance (mm) Example 1 1.13 Example 2 1.08 (eliminated at 925 seconds) Example 3 1.01 (lost in 850 seconds) Example 4 0.49 Example 5 0.49 Example 6 0.62 Comparative Example 1 Dropped in 0 second Comparative Example 2 0.55

In Table 1, dropout means that all the adhesive areas are peeled off, and Examples 2 and 3 measure the pushing distance before dropout. Comparative Example 2 shows the pushing distance at the level of the example, however, the productivity was lowered due to the solvent, the environmental safety problem occurred, and heat wrinkles and coating lines due to heat hardening were observed.

Claims (22)

A monomer component comprising a compound represented by the following formula (1), or a polymer component having the monomer component as a polymerization unit,
Sensitive adhesive composition capable of primary crosslinking by light containing one of the wavelengths in the UV region and secondary crosslinking by light having a wavelength lower than the wavelength in the primary crosslinking:
[Chemical Formula 1]

Wherein R ₁ is hydrogen or an alkyl group, X ₁ and X ₂ are each independently oxygen or a single bond, A is an alkylene group, an alkylidene group or a single bond, R ₂ to R ₆ are each independently Hydrogen, an alkyl group or Q, each of R ₇ to R ₁₁ is independently hydrogen or an alkyl group, and Q is a single bond, an alkylene group, an alkylidene group or a carbonyl group. The pressure-sensitive adhesive composition according to claim 1, wherein the primary crosslinking light has a wavelength range of 330 nm to 380 nm. The pressure-sensitive adhesive composition according to claim 1, wherein the secondary crosslinking light has a wavelength range of from 260 nm to 330 nm. The pressure-sensitive adhesive composition according to claim 1, which is a solvent-free type. The pressure-sensitive adhesive composition according to claim 1, wherein the monomer component or the polymer component forms a partial polymer. The pressure-sensitive adhesive composition according to claim 1, wherein the compound represented by the formula (1) is contained in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the monomer component or the polymer component. The pressure-sensitive adhesive composition according to claim 1, wherein the monomer component further comprises a (meth) acrylic acid ester-based monomer. The pressure-sensitive adhesive composition according to claim 5, wherein the (meth) acrylic acid ester monomer and the compound represented by the formula (1) are contained in a weight ratio of 50 to 99.9 parts by weight and 0.1 to 8 parts by weight, respectively. The pressure-sensitive adhesive composition according to claim 1, wherein the monomer component further comprises a compound represented by the following formula (2):
(2)

R ₁ is hydrogen or an alkyl group, X and Z are each independently an alkylene group or an alkylidene group, n is a number of 0 to 5, and R ₁₄ is an alkyl group or an aryl group. The pressure-sensitive adhesive composition according to claim 9, wherein the compound represented by the general formula (2) is contained in an amount of 5 to 25 parts by weight based on 100 parts by weight of the monomer component or the polymer component. The pressure-sensitive adhesive composition according to claim 1, wherein the monomer component further comprises a compound represented by the following formula (3):
(3)

In Formula 3, R ₁ is hydrogen or an alkyl group, A and T are each independently an alkylene group or an alkylidene group, and n is a number of 0 to 5. The pressure-sensitive adhesive composition according to claim 11, wherein the compound represented by the general formula (3) is contained in an amount of 5 to 25 parts by weight based on 100 parts by weight of the monomer component or the polymer component. The pressure-sensitive adhesive composition according to claim 1, wherein the monomer component further comprises a compound represented by the following formula (4):
[Chemical Formula 4]

In Formula 4, R ₁ is hydrogen or an alkyl group, and U is a monovalent residue derived from an aliphatic saturated hydrocarbon cyclic compound. The pressure-sensitive adhesive composition according to claim 13, wherein the compound represented by the general formula (4) is contained in an amount of 1 to 15 parts by weight based on 100 parts by weight of the monomer component or the polymer component. The pressure-sensitive adhesive composition according to claim 1, further comprising a polyfunctional acrylate. The pressure-sensitive adhesive composition according to claim 15, wherein the polyfunctional acrylate is contained in an amount of 0.05 to 50 parts by weight based on 100 parts by weight of the monomer component or the polymer component. The pressure-sensitive adhesive composition according to claim 1, further comprising a photoinitiator. The pressure-sensitive adhesive composition according to claim 1, further comprising a polyfunctional crosslinking agent. The pressure-sensitive adhesive composition according to claim 18, wherein the polyfunctional crosslinking agent is at least one selected from the group consisting of an isocyanate compound, an epoxy compound, an aziridine compound and a metal chelate compound. The pressure-sensitive adhesive composition according to claim 18, wherein the polyfunctional crosslinking agent is a mixture of an aliphatic linear polyvalent NCO and an aliphatic cyclic polyvalent NCO. The pressure-sensitive adhesive composition according to claim 18, wherein the multifunctional crosslinking agent is contained in an amount of 0.01 to 20 parts by weight based on 100 parts by weight of the monomer component or the polymer component. A polarizer; And a pressure-sensitive adhesive layer formed on one surface of the polarizer and containing the pressure-sensitive adhesive composition according to claim 1 in a cured state.