JP6630728B2 - Pressure-sensitive adhesive composition for optical film, pressure-sensitive adhesive layer, pressure-sensitive optical film, and display device - Google Patents

Description

  The present invention relates to a pressure-sensitive adhesive composition for an optical film, a pressure-sensitive adhesive layer, a pressure-sensitive adhesive optical film, and a display device including the same.

  The display device includes a display element such as a liquid crystal cell. Such a display element may have various films attached thereto according to a desired function and purpose. For example, a liquid crystal cell includes polarizing films on both sides according to a specific image forming method. In addition, the liquid crystal cell may further include a retardation plate, a viewing angle widening film, a brightness enhancement film, various protective films, and the like, in addition to the polarizing film, for improving image quality. Hereinafter, a film to be attached to a display element is generally referred to as an optical film.

  Generally, a display element may include one or more optical films. For example, the optical film may be directly attached to the display element, or a large number of optical films may be laminated on the display element. In this case, the optical film may be attached to the display element or another optical film using an adhesive.

  At this time, the optical film is often used in the form of an adhesive optical film having an adhesive layer formed on at least one surface. When an adhesive optical film is used, there is an advantage that a drying step of the adhesive can be omitted.

  However, when the pressure-sensitive adhesive optical film is adhered to the display element, an error may occur in the bonding position, or foreign matter may enter the bonding surface. In this case, the display element is reused by peeling the optical film from the display element. Therefore, the adhesive for optical films is required to have removability (reworkability). Specifically, the reworkability means that the pressure-sensitive adhesive layer formed of the pressure-sensitive adhesive for an optical film does not destroy the display element at the time of peeling, and does not leave contamination such as a residual adhesive on the display element at the time of peeling.

  In order to improve the reworkability of the pressure-sensitive adhesive layer, the adhesive force of the pressure-sensitive adhesive for an optical film must be reduced. Such reworkability is more important in thinned optical films and display devices, as is the case with recent trends. For example, when the thickness of the optical film and the display element is reduced due to the reduction in thickness, the breaking strength of the optical film and the display element is reduced. Therefore, the adhesive used for the thin optical film and the display element needs to further reduce the adhesive force in order to prevent breakage.

On the other hand, the adhesive is also required to have a reliability (durability) capable of stably bonding the optical film and the optical film or the optical film and the display element. However, if the adhesive force of the pressure-sensitive adhesive is significantly reduced in order to ensure the reworkability of the pressure-sensitive adhesive layer, the reliability of the pressure-sensitive adhesive may be greatly damaged. Thus, there is a problem that it is very difficult to achieve both reworkability and reliability of the pressure-sensitive adhesive for an optical film. Such a problem has not been particularly easy to solve when the optical film and the display element are thin.
JP-A-2010-275524 (hereinafter, Patent Document 1), JP-A-2008-503638 (hereinafter, Patent Document 2), JP-A-8-199130 (JP1996-199130A) (hereinafter, Patent Document 3) and Japanese Patent Application Laid-Open No. 8-209103 (JP1996-209103A) (hereinafter referred to as Patent Document 4) discloses a technique relating to an adhesive. However, the techniques disclosed in Patent Documents 1 to 4 cannot solve the above-described problem.

  Patent Document 1 proposes a pressure-sensitive adhesive composition for an optical film, comprising a (meth) acrylic polymer and a polyether having a reactive silyl group. However, the pressure-sensitive adhesive disclosed in Patent Literature 1 cannot reduce the adhesive strength to a degree sufficient to rework a thin soft optical film and a display element.

  Further, Patent Document 2 discloses an acrylic pressure-reduced acrylic polymer containing a hydroxyl-containing but not carboxyl-containing acrylic copolymer, a crosslinking agent and a polyether-modified polydimethylsiloxane copolymer having an HLB value of 4 to 13. An adhesive composition is disclosed. However, with the technology disclosed in Patent Document 2, it was difficult to ensure durability.

  Patent Documents 3 and 4 disclose a pressure-sensitive adhesive composition characterized by being constituted by mixing a crosslinking agent and a silicate oligomer in an acrylic resin. However, when the amount of the carboxyl group in the acrylic resin was large, the adhesive strength could not be sufficiently reduced. For this reason, the techniques of Patent Documents 3 and 4 cannot secure reworkability especially for a thin, soft optical film and a display element.

JP 2010-275524 A JP 2008-503638 A JP-A-8-199130 JP-A-8-209103

  An object of the present invention is to provide a pressure-sensitive adhesive composition for an optical film that not only can achieve both reworkability and reliability but also has excellent workability.

  It is another object of the present invention to provide a pressure-sensitive adhesive layer, a pressure-sensitive adhesive optical film formed of the pressure-sensitive adhesive composition for an optical film, and a display device including the same.

  The above and other objects of the present invention can all be achieved by the present invention described below.

  The pressure-sensitive adhesive composition for an optical film of the present invention includes a pressure-sensitive resin having an acid value of 0 mgKOH / g to 20.0 mgKOH / g, a silicate oligomer represented by the following Chemical Formula 1, and a crosslinking agent.

[Formula 1]

In the chemical formula 1, R _{1 to} R ₄ are each independently hydrogen, an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and X ₁ and X ₂ are each independently Hydrogen, an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and n is an integer of 1 to 100.

  The pressure-sensitive adhesive layer of one embodiment of the present invention can be formed from the pressure-sensitive adhesive composition for an optical film.

  The pressure-sensitive adhesive layer according to another embodiment of the present invention includes a pressure-sensitive resin containing at least one of a (meth) acrylic polymer, a urethane polymer and a polyester, a silicate oligomer represented by the following Chemical Formula 1, and a peroxide-based resin. The adhesive layer formed of the composition containing the cross-linking agent is left at a temperature of 23 ° C. and a humidity of 65% RH for about 1 hour from the formation of the adhesive layer. % By weight.

[Formula 1]

In the chemical formula 1, R _{1 to} R ₄ are each independently hydrogen, an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and X ₁ and X ₂ are each independently Hydrogen, an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and n is an integer of 1 to 100.

  [Equation 1]

Gel fraction (% by weight) = {(Wc−Wa) / (Wb−Wa)} × 100

  In the above formula 1, Wb is the weight when 0.2 g of the adhesive layer is covered with a fluororesin (TEMISHNTF-1122, Nitto Denko Corporation), and Wa is the weight of the fluororesin. Further, Wc extracts a soluble component by immersing the adhesive layer covered with the fluororesin in 40 ml of ethyl acetate at about 23 ° C. for about 7 days to extract a soluble component. This is the weight of the pressure-sensitive adhesive layer covered with a fluororesin from which the soluble components have been removed after drying at about 2 hours for about 2 hours.

  The pressure-sensitive adhesive optical film of the present invention may include one of a polarizer, a protective layer formed on one surface of the polarizer, and the pressure-sensitive adhesive layer formed on the other surface of the polarizer.

  The display device of the present invention may include the above-mentioned adhesive optical film.

  The present invention provides a pressure-sensitive adhesive composition for an optical film, a pressure-sensitive adhesive layer, a pressure-sensitive adhesive optical film, and a display device including the same, which can not only achieve reworkability and reliability but also have excellent workability. Has an effect.

It is sectional drawing which showed the adhesion type optical film concerning one specific example. It is sectional drawing which showed the adhesive type optical film of another specific example. It is sectional drawing which showed the display device of one specific example. It is sectional drawing which showed the display apparatus of another specific example.

  <Adhesive composition for optical film>

  The pressure-sensitive adhesive composition for an optical film of the present invention includes a pressure-sensitive resin having an acid value of about 0 mgKOH / g to about 20.0 mgKOH / g, a silicate oligomer, and a crosslinking agent. Hereinafter, the composition for forming the pressure-sensitive adhesive composition for an optical film of a specific example will be described.

  (A) Adhesive resin

  One specific example of the adhesive resin has an acid value of about 0 mgKOH / g to about 20 mgKOH / g. Specifically, the adhesive resin has an acid value of 0 mgKOH / g, 0.1 mgKOH / g, 0.2 mgKOH / g, 0.3 mgKOH / g, 0.4 mgKOH / g, 0.5 mgKOH / g, 0.6 mgKOH / g. g, 0.7 mg KOH / g, 0.8 mg KOH / g, 0.9 mg KOH / g, 1.0 mg KOH / g, 1.1 mg KOH / g, 1.2 mg KOH / g, 1.3 mg KOH / g, 1.4 mg KOH / g, It may be 1.5 mg KOH / g, 1.6 mg KOH / g, 1.7 mg KOH / g, 1.8 mg KOH / g, 1.9 mg KOH / g, 2.0 mg KOH / g. Further, the adhesive resin may have an acid value in a range of at least one of the above-mentioned numerical values and one or less of the above-mentioned numerical values. For example, the acid value of the adhesive resin may be about 10 mg KOH / g or less, more specifically about 3 mg KOH / g or less, and more specifically about 1 mg KOH / g or less. For example, the adhesive resin may have an acid value of more than about 0 mgKOH / g and about 20 mgKOH / g or less. Within the above range, the pressure-sensitive adhesive resin has excellent adhesive strength and reliability of the pressure-sensitive adhesive composition, and can balance reworkability.

  The adhesive resin may include, as a structural unit, a monomer containing a hydroxyl group-containing monomer as a structural unit. For example, the hydroxyl group-containing monomer may include a (meth) acrylate having a hydroxy group, a polyol, or the like, but is not limited thereto.

  The adhesive resin is not particularly limited as long as it has adhesiveness and has an acid value of about 0 mgKOH / g to about 20 mgKOH / g. Such an adhesive resin may include, for example, one or more of a (meth) acrylic polymer, a urethane polymer, and a polyester. The adhesive resin may be composed of only one of these, or may be composed of a mixture of these resins. Further, the adhesive resin may be a copolymer of these resins. When such an adhesive resin is used, the adhesive composition is advantageous in satisfying the optical characteristics of the optical film.

  In one specific example, the adhesive resin may include a (meth) acrylic polymer. The (meth) acrylic polymer may be a polymer containing an alkyl (meth) acrylate monomer as a polymerized unit constituting a main skeleton; and an alkyl (meth) acrylate monomer and other copolymers. (Hereinafter, referred to as an alkyl (meth) acrylate copolymer) containing a monomer as a polymerized unit.

  Examples of the alkyl (meth) acrylate monomer include a straight-chain or branched-chain alkyl group having 1 to 18 carbon atoms. For example, as the alkyl group, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, amyl, hexyl, cyclohexyl, heptyl, 2-ethylhexyl, isooctyl, nonyl, decyl Groups, isodecyl group, dodecyl group, isomiristyl group, lauryl group, tridecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group and the like. These may be used alone or in combination. Specifically, the average carbon number of these alkyl groups may be 3 to 9.

  The alkyl (meth) acrylate copolymer can be manufactured by copolymerizing an alkyl (meth) acrylate monomer and one or more comonomers. The comonomer means a monomer polymerizable with the alkyl (meth) acrylate monomer, and is not particularly limited as long as it is polymerizable with the alkyl (meth) acrylate monomer. The one or more comonomers may have a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group. In this case, the adhesiveness and heat resistance of the adhesive resin can be improved.

  Examples of the comonomer include 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, Hydroxyl group-containing monomers such as 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate and (4-hydroxymethylcyclohexyl) -methyl acrylate; ) Carboxyl group-containing monomers such as acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid; anhydrides such as maleic anhydride and itaconic anhydride Group-containing monomer; with caprolactone of acrylic acid Sulfone such as styrenesulfonic acid, arylsulfonic acid, 2- (meth) acrylamido-2-methylpropanesulfonic acid, (meth) acrylamidopropanesulfonic acid, sulfopropyl (meth) acrylate, (meth) acryloyloxynaphthalenesulfonic acid An acid group-containing monomer; a phosphate group-containing monomer such as 2-hydroxyethylacryloyl phosphate may be included.

  The comonomer is, for example, (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-butyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methylolpropane (meth) acrylamide (N-substituted) amide monomers such as aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, and (meth) acryl such as t-butylaminoethyl (meth) acrylate Alkylaminoalkyl acid monomers; alkoxyalkyl (meth) acrylate monomers such as methoxyethyl (meth) acrylate and ethoxyethyl (meth) acrylate; N- (meth) acryloyloxymethylene succinimide; (Meth) acryloyl-6-oxyhexamethylene succinimide, N- (meth ) Succinimide-based monomers such as acryloyl-8-oxyoctamethylene succinimide and N-acryloylmorpholine; maleimide-based monomers such as N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide and N-phenylmaleimide; -Itaconimide-based monomers such as -methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N-octylitaconimide, N-2-ethylhexylitaconimide, N-cyclohexylitaconimide, N-laurylitaconimide; And the like. In this case, there may be an effect of modifying the pressure-sensitive adhesive composition.

  The comonomer, for example, as a modified monomer, vinyl acetate, vinyl propionate, N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinyl Vinyl monomers such as imidazole, vinyl oxazole, vinyl morpholine, N-vinyl carboxylic acid amides, styrene, α-methylstyrene, N-vinylcaprolactam; cyanoacrylate monomers such as acrylonitrile and methacrylonitrile; Epoxy group-containing acrylic monomers such as glycidyl (meth) acrylate; polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, methoxyethylene glycol (meth) acrylate, (meth) acyl Glycol-based acrylic ester monomers such as methoxypolypropylene glycol luate; acrylate-based monomers such as tetravidrofurfuryl (meth) acrylate, fluorine (meth) acrylate, silicon (meth) acrylate, and 2-methoxyethyl acrylate Body; etc. can also be used. Moreover, you may use isoprene, butadiene, isobutylene, vinyl ether, etc.

  Further, the comonomer may include, for example, a silane-based monomer containing a silicon atom. Examples of the silane-based monomer include 3-acryloxypropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 4-vinylbutyltrimethoxysilane, 4-vinylbutyltriethoxysilane, and 8-vinyloctyltrimethoxy. It may include silane, 8-vinyloctyltriethoxysilane, 10-methacryloyloxydecyltrimethoxysilane, 10-acryloyloxydecyltrimethoxysilane, 10-methacryloyloxydecyltriethoxysilane, 10-acryloyloxydecyltriethoxysilane, and the like. .

  Further, the comonomer includes tripropylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, bisphenol A diglycidyl ether di (meth) acrylate, Neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate (Meth) acrylic acid such as acrylate and caprolactone-modified dipentaerythritol hexa (meth) acrylate; and (meth) acryloyl such as esterified product with polyhydric alcohol ; And a vinyl group; an unsaturated double bond, such as may comprise a multifunctional monomer having two or more.

  The comonomer has two or more unsaturated double bonds, such as a (meth) acryloyl group and a vinyl group, added as a functional group similar to the monomer component to a skeleton of polyester, epoxy, urethane, or the like. Polyester (meth) acrylate, epoxy (meth) acrylate, urethane (meth) acrylate and the like may be included.

  The content of the comonomer is about 0% to about 20% by weight based on the total weight of all monomers (monomers used as polymerized units of the alkyl (meth) acrylate copolymer). It may be about 0.1% to about 15% by weight, specifically about 0.1% to about 10% by weight. Within the above range, the pressure-sensitive adhesive composition is advantageous for achieving both reworkability and reliability.

  In one specific example, the (meth) acrylic copolymer may use a hydroxyl group-containing monomer as a comonomer. In this case, the adhesiveness and durability of the pressure-sensitive adhesive composition can be improved. Since the hydroxyl group-containing monomer has a high reactivity with the crosslinking agent, the cohesiveness and heat resistance of the pressure-sensitive adhesive composition can be further improved. Further, the hydroxyl group-containing monomer can further improve the reworkability of the pressure-sensitive adhesive composition. When a hydroxyl group-containing monomer is contained as a comonomer, the ratio thereof is about 0.01% to about 15% by weight, about 0.03% by weight to about It may be about 10%, about 0.05% to about 7% by weight.

  In other specific examples of the (meth) acrylic copolymer, a carboxyl group-containing monomer may be used as a comonomer. In this case, when the pressure-sensitive adhesive composition contains a crosslinking agent, the comonomer can form a reaction point with the crosslinking agent. Further, the comonomer can further improve the reworkability of the pressure-sensitive adhesive composition. When a carboxyl group-containing monomer is contained as a comonomer, the ratio thereof is about 0.05% to about 10% by weight, and about 0.1% by weight based on the total weight of all the monomers. % To about 8% by weight, about 0.2% to about 6% by weight.

  Still another specific example of the (meth) acrylic copolymer may use a hydroxyl group-containing monomer and a carboxyl group-containing monomer as a comonomer.

  In a specific example, the (meth) acrylic polymer may have a weight average molecular weight of about 300,000 to about 3,000,000. Specifically, the weight average molecular weight of the (meth) acrylic polymer may be from about 500,000 to about 2.5 million, more specifically from about 800,000 to about 2.3 million. In this case, the pressure-sensitive adhesive composition can have improved durability and heat resistance. More specifically, the weight average molecular weight of the (meth) acrylic polymer may be from about 700,000 to about 2.3 million. Within the above range, the heat resistance of the pressure-sensitive adhesive composition is further improved, the viscosity is appropriate, and it may be advantageous for coating. In addition, a process of introducing a large amount of diluting solvent can be omitted, and costs can be reduced. In this specification, the weight average molecular weight means a value measured by GPC (gel permeation chromatography) and calculated in terms of polystyrene.

  In one embodiment, the (meth) acrylic polymer may have a glass transition temperature of about -10C or less, about -25C or less. Within the above range, the pressure-sensitive adhesive composition has improved flexibility and initial tackiness, and can exhibit sufficient adhesive strength even at a low pressure. In addition, the lower limit of the glass transition temperature may be about -100C or more, about -80C or more, or about -70C or more. Within such a range, a decrease in the heat resistance of the polyester can be prevented.

  As the polymerization method of the (meth) acrylic polymer, a known polymerization method such as solution polymerization, bulk polymerization, emulsion polymerization, and various kinds of radical polymerization can be appropriately selected. The (meth) acrylic polymer obtained by the polymerization method may be any of a random copolymer, a block copolymer, and a graft copolymer.

  In one embodiment, the (meth) acrylic polymer can be made by solution polymerization. In this case, as the polymerization solvent, for example, ethyl acetate, toluene and the like may be used. Specifically, the solution polymerization can be carried out by adding a polymerization initiator under a stream of an inert gas such as nitrogen, usually at about 50 ° C. to 85 ° C., for about 5 hours to about 30 hours. .

  In another embodiment, the (meth) acrylic polymer can be made by radical polymerization. The polymerization initiator, chain transfer agent, emulsifier, and the like used in the radical polymerization are not particularly limited, and may be appropriately selected and used. The weight average molecular weight of the (meth) acrylic polymer can be controlled by adjusting the amount of the polymerization initiator, the chain transfer agent, and the like, the reaction conditions, and the like. As the polymerization initiator, for example, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-amidinopropane) dihydrochloride, 2,2′-azobis [2- (5-methyl-2-) Imidazolin-2-yl) propane] dihydrochloride, 2,2′-azobis (2-methylpropionamidine) disulfate, 2,2′-azobis (N, N′-dimethyleneisobutylamidine), 2,2 ′ Azo-based initiators such as -azobis [N- (2-carboxyethyl) -2-methylpropionamidine] hydrate (VA-057, manufactured by Wako Pure Chemical Industries, Ltd.), peroxide-based initiators, persulfate Redox initiators such as a combination of a salt and sodium bisulfite, a peroxide and a reducing agent such as a combination of peroxide and sodium ascorbate, and the like, but may be limited to these. It will not be done.

  The polymerization initiators may be used alone or in combination of two or more. The content of the polymerization initiator is, for example, about 0.005 parts by weight to about 1 part by weight, about 0.02 parts by weight to about 0.5 parts by weight, based on 100 parts by weight of the whole monomer. Is also good. For example, the (meth) acrylic polymer (A) having the above weight average molecular weight can be produced using 2,2′-azobisisobutyronitrile as a polymerization initiator. In this case, the specific amount of the polymerization initiator to be used is about 0.06 parts by weight to about 0.2 parts by weight or about 0.08 parts by weight based on 100 parts by weight of the total amount of the monomer components. It may be about 0.175 parts by weight.

  Examples of the chain transfer agent include lauryl mercaptan, glycidyl mercaptan, mercaptoacetic acid, 2-mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglycolate, 2,3-dimercapto-1-propanol, and the like. The chain transfer agents may be used alone or as a mixture of two or more. The content of the chain transfer agent may be about 0.1 part by weight or less based on 100 parts by weight of the total monomer components.

  Examples of the emulsifier include anionic emulsifiers such as sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzenesulfonate, ammonium polyoxyethylene alkyl ether sulfate and sodium polyoxyethylene alkyl phenyl ether sulfate; polyoxyethylene alkyl ether, polyoxyethylene Examples include nonionic emulsifiers such as alkylphenyl ether, polyoxyethylene fatty acid ester, and polyoxyethylene-polyoxypropylene block polymer. These emulsifiers may be used alone or in combination of two or more. Further, as a reactive emulsifier, as an emulsifier into which a radical polymerizable functional group such as a propenyl group or an aryl ether group is introduced, specifically, for example, Aqualon HS-10, HS-20, KH-10, BC-05 , BC-10, and BC-20 (all of which are products of Daiichi Kogyo Seiyaku Co., Ltd.), Adecaria soap SE10N, and SR-10N (products of ADEKA Chemical Supply Co., Ltd.). Since the reactive emulsifier is introduced into the polymer chain after the polymerization, the water resistance can be improved. The emulsifier is used in an amount of about 0.3 to about 5 parts by weight, and about 0.5 to about 2 parts by weight based on polymerization stability and mechanical stability, based on 100 parts by weight of the total amount of the monomer components. It may be by weight.

  Next, the urethane polymer will be described. In one specific example, the urethane polymer that can be used as the adhesive resin may be, for example, one obtained by reacting a polyol with an isocyanate. Specifically, examples of the polyol include a polyester polyol and a polyether polyol.

  As the polyester polyol, a known polyester polyol may be used.

  The polyester polyol of one specific example is obtained by dehydrating and polymerizing an acid component and a divalent or higher valent polyol component. Examples of the acid component include terephthalic acid, adipic acid, azelaic acid, sebacic acid, phthalic anhydride, isophthalic acid, trimellitic acid, and the like. Examples of the divalent or higher polyol component include ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, 1,6-hexane glycol, 3-methyl-1,5-pentanediol, 3,3′-dimethylolheptane, and poly (diol). Oxyethylene glycol, polyoxypropylene glycol, 1,4-butanediol, neopentyl glycol, 2-butyl-3-ethyl-1,5-pentanediol, 2-butyl-4-ethyl-1,5-pentanediol, etc. And at least one of trihydric alcohols including glycerin and trimethylolpropane; and tetrahydric alcohols including pentaerythritol.

  Polyester polyols of other specific examples may be polyester polyols obtained by ring-opening polymerization of lactones such as polycaprolactone, poly (β-methyl-γ-valerolactone) and polyvalerolactone.

  The molecular weight of the polyester polyol can be used from a low molecular weight to a high molecular weight. Specifically, a polyester polyol having a molecular weight of about 1,000 to about 5,000, more specifically, a polyester polyol having a molecular weight of about 2,500 to about 3,500 may be used. Within the above range, the polyester polyol can prevent gelation of the polyurethane and improve cohesion of the polyurethane itself. The amount of the polyester polyol used may be about 10 mol% to about 70 mol%, more specifically, about 35 mol% to about 65 mol% in the polyol constituting the polyurethane.

  Known polyether polyols may be used as the polyether polyol.

  The polyether polyol of one specific example is, for example, using a low molecular weight polyol such as propylene glycol, ethylene glycol, glycerin, and trimethylolpropane as an initiator to polymerize an oxirane compound such as ethylene oxide, propylene oxide, butylene oxide, and tetrahydrofuran. It may be a polyether polyol obtained by this. Specifically, examples of the polyether polyol include those having two or more functional groups including polypropylene glycol, polyethylene glycol, polytetramethylene glycol, and the like.

  In another embodiment, the initiator is glycols such as ethylene glycol, 1,4-butanediol, neopentyl glycol, butylethylpentanediol, glycerin, trimethylolpropane, pentaerythritol; and ethylenediamine, N-aminoethyl Polyamines such as ethanolamine, isophoronediamine and xylylenediamine; may be used in combination.

  The molecular weight of the polyether polyol can be used from a low molecular weight to a high molecular weight. The polyether polyol may specifically have a weight average molecular weight of about 1,000 to about 5,000, more specifically, about 2,500 to about 3,500. Within the above range, the polyether polyol can prevent the urethane polymer from gelling and improve the cohesive force of the polyurethane itself.

  The content of the polyether polyol may be about 20 mol% to about 80 mol%, more specifically, about 40 mol% to about 65 mol% in the polyol constituting the polyurethane.

  In one embodiment, a bifunctional polyether polyol may be used as the polyether polyol. In another embodiment, the polyether polyol may include a polyether polyol having a molecular weight of about 1,000 to about 5,000 and having at least three or more hydroxyl groups in one molecule. In this case, the polyether polyol can provide the urethane polymer with a balance between adhesive strength and removability. In yet another embodiment, the polyether polyol may have a molecular weight of about 2,500 to about 3,500, and may use some or all of the polyol having at least three functions or more. In this case, the polyether polyol can prevent the urethane polymer from gelling, improve the reactivity, and improve the cohesive force of the polyurethane itself.

  The isocyanate used in one specific example may be an organic polyisocyanate compound including a known aromatic polyisocyanate, aliphatic polyisocyanate, araliphatic polyisocyanate, alicyclic polyisocyanate and the like.

  Aromatic polyisocyanates include, for example, 1,3-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6- Tolylene diisocyanate, 4,4'-toluidine diisocyanate, 2,4,6-triisocyanate toluene, 1,3,5-triisocyanate benzene, dianisidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4 ', 4 "-Triphenylmethane triisocyanate and the like.

  Aliphatic polyisocyanates include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, 2,4 , 4-trimethylhexamethylene diisocyanate and the like.

  Aromatic polyisocyanates include ω, ω′-diisocyanate-1,3-dimethylbenzene, ω, ω′-diisocyanate-1,4-dimethylbenzene, ω, ω′-diisocyanate-1,4-diethylbenzene, It may contain 4-tetramethylxylylene diisocyanate, 1,3-tetramethyl xylylene diisocyanate, or the like.

  The alicyclic polyisocyanate is 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, methyl 2,4- It may contain cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4'-methylenebis (cyclohexyl isocyanate), 1,4-bis (isocyanatomethyl) cyclohexane, 1,4-bis (isocyanatomethyl) cyclohexane, and the like.

  As the isocyanate, a trimethylolpropane adduct of the polyisocyanate, a burette that has been reacted with water, a trimer having an isocyanurate ring, and the like can also be used in combination.

  In one specific example, as the polyisocyanate, for example, 4,4′-diphenylmethane diisocyanate, hexamethylene diisocyanate, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate) and the like may be used.

  As the catalyst used for synthesizing the urethane polymer, a known catalyst may be used, and examples thereof include tertiary amine compounds and organometallic compounds.

  Examples of the tertiary amine compound include triethylamine, triethylenediamine, 1,8-diazabicyclo (5,4,0) -undecene-7 (DBU), and the like.

  Examples of the organometallic compound include a tin compound and a non-tin compound. Examples of tin compounds include dibutyltin dichloride, dibutyltin oxide, dibutyltin dibromide, dibutyltin dimaleate, dibutyltin dilaurate (DBTDL), dibutyltin diacetate, dibutyltin sulfide, tributyltin sulfide, tributyltin oxide, tributyltin acetate, Examples thereof include triethyltin ethoxide, tributyltin ethoxide, dioctyltin oxide, tributyltin chloride, tributyltin trichloroacetate, and tin 2-ethylhexanoate.

  Examples of the non-tin compound include titanium compounds such as dibutyl titanium dichloride, tetrabutyl titanate and butoxy titanium trichloride; lead compounds such as lead oleate, lead 2-ethylhexanoate, lead benzoate and lead naphthenate; Iron-based such as iron ethylhexanoate and iron acetylacetonate; cobalt-based such as cobalt benzoate and cobalt 2-ethylhexanoate; zinc-based such as zinc naphthenate and zinc 2-ethylhexanoate; and zirconium naphthenate Can be exemplified.

  When one or more of the catalysts described above are used during the synthesis of the urethane polymer according to one embodiment, the reaction time of the urethane polymer can be reduced.

  When two or more of the above catalysts are used in combination when synthesizing the urethane polymer of another specific example, gelation of the urethane polymer can be prevented, and the turbidity of the reaction solution can be reduced. In particular, when a urethane polymer is synthesized using both a polyester polyol and a polyether polyol having different reactivity as the polyol, the effect of preventing gelation can be further improved. When two or more of the above-mentioned catalysts are used, the reaction rate and the selectivity of the catalyst during the synthesis of the urethane polymer can be controlled. As a combination of the two or more catalysts, a tertiary amine / organic metal system, tin system / non-tin system, tin system / tin system, or the like may be used. Specifically, a combination of dibutyltin dilaurate and tin 2-ethylhexanoate may be used.

  In one embodiment, when dibutyltin dilaurate and tin 2-ethylhexanoate are used in combination as a catalyst for urethane polymer synthesis, the weight ratio of dibutyltin dilaurate: tin 2-ethylhexanoate is less than about 1: 1. And specifically from about 1: 0.2 to about 1: 0.6. Within the above range, the effect of reducing the gelation of the urethane polymer can be further improved.

  The amount of the above-mentioned catalyst may be about 0.01% to about 1.0% by weight based on the total amount of the polyol and the isocyanate.

  One specific example of a polyurethane may be used in admixture with a multifunctional isocyanate compound. The multifunctional isocyanate compound may include, for example, the above-mentioned organic polyisocyanate compounds and their adducts of trimethylolpropane, burettes reacted with water, trimers having an isocyanurate ring, and the like.

  In one embodiment, when the urethane polymer and the multi-functional isocyanate are used in combination, the multi-functional isocyanate may be included in 1 to 20 parts by weight based on 100 parts by weight of the urethane polymer. Specifically, it is 2 to 10 parts by weight. Within the above range, the adhesive strength and cohesive strength of the adhesive resin containing the urethane polymer can be further improved.

  When synthesizing the urethane polymer of one embodiment, the reaction temperature may be about 100 ° C. or less, and more specifically, about 85 ° C. to about 95 ° C. Within the above range, it is advantageous to control the crosslinked structure of the urethane polymer, through which a polyurethane having a predetermined molecular weight and a predetermined chemical structure can be obtained.

  In one embodiment, the polyurethane has a weight average molecular weight of about 10,000 to about 200,000, specifically about 15,000 to about 100,000, more specifically about 20,000 to about 50,000, Is also good. Within the above range, the adhesive strength and cohesive strength of the adhesive resin containing the urethane polymer can be further improved, and the heat resistance and the mechanical strength can be further improved. Further, within the above range, the loss of the flexibility of the adhesive resin can be prevented, and thereby the initial adhesiveness and the overall adhesive strength can be improved. In this case, the pressure-sensitive adhesive composition can be easily bonded even at a low pressure.

  One embodiment of the polyurethane may have a glass transition temperature of about -10C or less, about -25C or less. Within the above range, the loss of flexibility of the adhesive resin can be prevented, and thereby the initial adhesiveness and the overall adhesive strength can be improved. In this case, the pressure-sensitive adhesive composition can be easily bonded even at a low pressure. Further, the glass transition temperature may have a lower limit of about −100 ° C. or more, about −80 ° C. or more, or about −70 ° C. or more. Within such a range, the heat resistance of the adhesive resin can be further improved.

  In one specific example, as the solvent used for diluting the urethane polymer, a known solvent may be used, and examples thereof include water, methyl ethyl ketone, ethyl acetate, toluene, xylene, and acetone. In one embodiment, toluene may be used as the solvent. In this case, the solubility of the urethane polymer, the boiling point of the solvent, and the like can be excellent.

  Next, polyester will be described. As one specific example, a polyester comprising a polyol component and a carboxylic acid component is used as a raw material, and is obtained by polycondensing these components.

  In one specific example, the polyol component used in the synthesis of the polyester may include one or more of a diol having an alkoxy group on a side chain and a polyol other than the diol having an alkoxy group on the side chain.

  Diols having an alkoxy group in the side chain include methoxyethylene glycol, methoxypropylene glycol, methoxybutylene glycol, ethoxyethylene glycol, ethoxypropylene glycol, ethoxybutylene glycol, dimethoxyethylene glycol, dimethoxypropylene glycol, dimethoxybutylene glycol, diethoxyethylene glycol , Diethoxypropylene glycol, diethoxybutylene glycol and the like may be used without limitation.

  Examples of the polyol other than the diol having an alkoxy group in a side chain include, for example, ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, Linear aliphatic diols such as 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol; neopentyl glycol, 2-methyl-1,3-propanediol, 2,2-diethyl-1 , 3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2-methyl -2,4-pentanediol, 2,4-diethyl-1,5-pentanediol, 1,3,5-trimethyl-1 3-pentanediol, and the like may be used aliphatic diol having a hydrocarbon group side chain such as 2-methyl-1,6-hexanediol. These may be used alone or in combination of two or more.

  In one specific example, as the polyol other than the diol having an alkoxy group in the side chain, a linear aliphatic diol having 2 to 6 carbon atoms, specifically, 1,4-butanediol, 1,6-hexanediol, Ethylene glycol or an aliphatic diol having a hydrocarbon group side chain having 1 to 4 carbon atoms, more specifically, neopentyl glycol may be used. In this case, the initial adhesiveness, mechanical strength, and heat resistance of the adhesive composition can be compatible with a good balance.

  Further, if necessary, the polyol component used at the time of synthesizing the polyester may further contain one or more of polyether diol and trihydric or higher polyhydric alcohol.

  Examples of the polyether diol include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol obtained by ring-opening polymerization of ethylene oxide, propion oxide, tetrahydrofuran, and the like, and one or more of these may be used.

  Examples of the trihydric or higher polyhydric alcohol include trimethylolethane, trimethylolpropane, glycerin, pentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, and 1,2,6-hexanetriol. And these may be used alone or in combination of two or more. In one specific example, trimethylolpropane may be used among the above-mentioned trihydric or higher polyhydric alcohols. In this case, the heat resistance of the polyester can be further improved. The content of the trihydric or higher polyhydric alcohol is not particularly limited, but is, for example, about 0.1 mol% to about 5.0 mol%, specifically about 0.5 mol% to about 3.0 mol%. There may be.

  The carboxylic acid component used during the synthesis of the polyester is not particularly limited, and may include, for example, a carboxylic acid having an alkoxy group in a side chain. In this case, an alkoxy group can be introduced into a side chain of the obtained polyester resin.

  Of course, a raw material component containing an alkoxy group in a side chain can be used for any of the above-mentioned polyol component and carboxylic acid component.

  Examples of the carboxylic acid having an alkoxy group in a side chain include polyvinyl ether described in Japanese Patent Application Publication No. 2004-307462.

  In one specific example, a carboxylic acid having a number average molecular weight of about 500 to about 3,000 and having an alkoxy group may be used. In this case, the polyester can balance the initial tackiness, mechanical strength, and heat resistance in a well-balanced manner.

  In addition, carboxylic acids other than carboxylic acids having an alkoxy group in a side chain include, for example, terephthalic acid, isophthalic acid, orthophthalic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, p-oxybenzoic acid, and the like. Saturated dicarboxylic acids such as aliphatic dicarboxylic acids such as aromatic dicarboxylic acids, succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, decanedicarboxylic acid and octadecanedicarboxylic acid; fumaric acid, maleic acid, itaconic acid and tetrahydroacid Unsaturated dicarboxylic acids such as phthalic acid, tetrachlorophthalic acid, hexahydrophthalic acid, and dimer acids; and the like, and one or more of these may be used.

  The carboxylic acid component of one specific example may be, if necessary, a trivalent acid such as trimellitic acid, trimesic acid, pyromellitic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, or the like. The above carboxylic acid may be further contained. In one specific example, among these, an aromatic dicarboxylic acid, specifically, terephthalic acid, isophthalic acid, an aliphatic dicarboxylic acid having 6 to 12 carbon atoms (including carbon of a carboxyl group), more specifically, sebacine Acids may be used. In this case, the polyester can balance the initial adhesiveness, mechanical strength, and heat resistance of the adhesive composition in a well-balanced manner.

  The content of the alkoxy group in the polyester resin of one specific example is not particularly limited, but about 5 to about 300, about 60 to about 150 alkoxy groups are introduced per one molecule of the polyester resin. Can be. Within such a range, the initial adhesive strength, mechanical strength, and heat resistance of the pressure-sensitive adhesive composition can be further improved.

  When synthesizing the polyester, the blending ratio of the polyol component may be about 1 equivalent or more, about 1.2 equivalents or more, and about 2.0 equivalents or less per equivalent of the carboxylic acid component. Within the above range, the molecular weight of the polyester can be adjusted to an appropriate range, and the yield can be further improved.

  At the time of the polyester polycondensation reaction, first, after the polymerization (esterification) reaction is performed, the condensation reaction can be performed. In such a polymerization (esterification) reaction, a catalyst may be used. Specific examples of the catalyst for the esterification reaction include titanium-based catalysts such as tetraisopropyl titanate and tetrabutyl titanate; antimony-based catalysts such as antimony trioxide; germanium-based catalysts such as germanium oxide; zinc acetate, manganese acetate, and the like. , Dibutyltin oxide and the like, and one or more of these may be used.

  The amount of the esterification catalyst may be about 1 ppm to about 10,000 ppm, about 10 ppm to about 5,000 ppm, about 10 ppm to about 3,000 ppm based on the total amount of the reactants. Within the above range, the effect of improving the degree of polymerization of the reaction, shortening the reaction time, and further reducing the side reaction can be realized.

  The reaction temperature during the polymerization (esterification) reaction may be from about 160 ° C to about 260 ° C, specifically from about 180 ° C to about 250 ° C, more specifically from about 200 ° C to about 250 ° C. Within the above range, the effect of improving the degree of polymerization of the reaction, shortening the reaction time, and further reducing the side reaction can be realized. The polymerization (esterification) reaction can be performed under normal pressure.

  In one embodiment, after the polymerization (esterification) reaction has been performed, a condensation reaction may be performed. At this time, an additional catalyst may be further added. When synthesizing the polyester, the catalyst used in the condensation reaction may be the same type and the same content as the catalyst usable in the above-described esterification reaction. In the condensation reaction, the reaction system is gradually depressurized at a reaction temperature of about 220 ° C. to about 260 ° C., more specifically, about 230 ° C. to about 250 ° C., and finally reacted at about 5 hPa or less. be able to. Within such a reaction temperature range, the reactivity of the reactants can be improved, and side reactions such as decomposition of the polyester can be further reduced.

  In one embodiment, the polyester has a weight average molecular weight of about 10,000 to about 200,000, specifically about 15,000 to about 100,000, more specifically about 20,000 to about 50,000, Is also good. Within the range of the weight average molecular weight, when applied as a pressure-sensitive adhesive composition, a sufficient cohesive force can be obtained, and further excellent heat resistance and mechanical strength can be secured. In addition, within the above range, the pressure-sensitive adhesive composition has improved flexibility and initial tackiness, and can exhibit sufficient adhesive strength even at a low pressure.

  In one embodiment, the polyester may have a glass transition temperature of about -10C or less, about -25C or less. Within the above range, the pressure-sensitive adhesive composition has improved flexibility and initial tackiness, and can exhibit sufficient adhesive strength even at a low pressure. In addition, the lower limit of the glass transition temperature may be about -100C or more, about -80C or more, or about -70C or more. Within such a range, a decrease in the heat resistance of the polyester can be prevented.

  In one specific example, a known solvent may be used as the solvent used for diluting the polyester. For example, water, methyl ethyl ketone, ethyl acetate, toluene, xylene, acetone and the like can be mentioned. In one specific example, methyl ethyl ketone and ethyl acetate may be used as the solvent. In this case, the solubility of the polyester, the boiling point of the solvent, and the like can be excellent.

  (B) Silicate oligomer

  The silicate oligomer according to one embodiment is represented by the following Chemical Formula 1.

  [Formula 1]

In the chemical formula 1, R _{1 to} R ₄ are each independently hydrogen, an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and X ₁ and X ₂ are each independently Hydrogen, an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and n is an integer of 1 to 100. The alkyl group and the aryl group may be substituted or unsubstituted. Further, the alkyl group may have a straight-chain structure or a branched-chain structure. Specifically, R _{1 to} R ₄ are each independently an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, and X ₁ and X ₂ are each independently hydrogen, carbon, It may be an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms. For example, R _{1 to} R ₄ may each independently be a methyl group, an ethyl group, or a phenyl group.

  Specifically, the silicate oligomer may be a single kind of oligomer or a mixture of plural kinds of oligomers.

  The weight average molecular weight of the silicate oligomer may be from about 300 to about 30,000. When the weight average molecular weight of the silicate oligomer falls within this range, the pressure-sensitive adhesive composition can achieve both reworkability and adhesiveness at an even higher level.

In a specific example, the silicate oligomer is a silicate oligomer in which R _{1 to} R ₄ , X ₁ and X ₂ are methyl groups and the weight-average molecular weight is about 300 to about 20,000 in the aforementioned chemical formula 1. R _{1 to} R ₄ , X ₁ and X ₂ are methyl groups, and a silicate oligomer having a weight average molecular weight of more than about 20,000 to about 30,000 or less; and R ₁ , R ₂ , R ₃ in the above formula 1 , R ₄ , X ₁ or X ₂ may comprise one or more of silicate oligomers containing a phenyl group.

The methyl silicate oligomer having a weight average molecular weight of about 300 to about 20,000, the methyl silicate oligomer having a weight average molecular weight of more than about 20,000 to about 30,000 or less, and R ₁ , R _{2 of} the formula 1 When R ₃ , R ₄ , X ₁ or X ₂ contains at least one silicate oligomer having a phenyl group, the pressure-sensitive adhesive composition can achieve both excellent reworkability and excellent adhesiveness.

  The weight average molecular weight of the silicate oligomer may be specifically from about 500 to about 25,000, more specifically from about 600 to about 5,000, and more specifically from about 800 to about 3,500. .

  Mixing ratio of adhesive resin and silicate oligomer

  The pressure-sensitive adhesive composition according to one embodiment may include about 0.01 parts by weight to about 50 parts by weight of the silicate oligomer based on 100 parts by weight of the pressure-sensitive adhesive resin. The pressure-sensitive adhesive composition contains about 0.01 parts by weight, 0.05 parts by weight, 0.1 parts by weight, 0.2 parts by weight, and 0.3 parts by weight of the silicate oligomer based on 100 parts by weight of the adhesive resin. 0.4 parts by weight, 0.5 parts by weight, 0.6 parts by weight, 0.7 parts by weight, 0.8 parts by weight, 0.9 parts by weight, 1 part by weight, 2 parts by weight, 3 parts by weight, 4 parts by weight Parts by weight 5 parts by weight, 6 parts by weight, 7 parts by weight, 8 parts by weight, 9 parts by weight, 10 parts by weight, 11 parts by weight, 12 parts by weight, 13 parts by weight, 14 parts by weight, 15 parts by weight, 16 parts by weight , 17 parts by weight, 18 parts by weight, 19 parts by weight, 20 parts by weight, 21 parts by weight, 22 parts by weight, 23 parts by weight, 24 parts by weight, 25 parts by weight, 26 parts by weight, 27 parts by weight, 28 parts by weight, 29 parts by weight Parts by weight, 30 parts by weight, 31 parts by weight, 32 parts by weight, 33 parts by weight, 34 parts by weight, 35 parts by weight, 36 parts by weight, 37 parts by weight, 38 parts by weight Parts, 39 parts by weight, 40 parts by weight, 41 parts by weight, 42 parts by weight, 43 parts by weight, 44 parts by weight, 45 parts by weight, 46 parts by weight, 47 parts by weight, 48 parts by weight, 49 parts by weight or 50 parts by weight May be. The pressure-sensitive adhesive composition may have a silicate oligomer content of at least one of the above-mentioned values and one or less of the above-mentioned values with respect to 100 parts by weight of the adhesive resin. For example, based on 100 parts by weight of the adhesive resin, about 0.01 parts by weight to about 50 parts by weight of the silicate oligomer, specifically about 0.5 parts by weight to about 20 parts by weight, more specifically about 0.5 parts by weight. It may comprise from about 10 parts by weight to about 10 parts by weight, more specifically from about 1 part by weight to about 5 parts by weight. Within the above range, the initial reworkability and the adhesive strength after heating of the pressure-sensitive adhesive composition can be further improved. Within the above range, the pressure-sensitive adhesive composition can achieve both reworkability and adhesiveness at an even higher level.

  Crosslinking agent

  The pressure-sensitive adhesive composition of one specific example may contain a crosslinking agent.

  As the crosslinking agent, an organic crosslinking agent or a multi-functional metal chelate may be used. Examples of the organic crosslinking agent include an isocyanate crosslinking agent, a carbodiimide crosslinking agent, an oxazoline crosslinking agent, a peroxide crosslinking agent, an epoxy crosslinking agent, and an imine crosslinking agent. Examples of the multifunctional metal chelate include a polyvalent metal having a covalent bond or a coordinate bond with an organic compound. Examples of the polyvalent metal atom include Al, Cr, Zr, Co, Cu, Fe, Ni, V, Zn, In, Ca, Mg, Mn, Y, Ce, Sr, Ba, Mo, La, Sn, and Ti. Examples can be given. Examples of atoms in the organic compound having a covalent bond or a coordinate bond include an oxygen atom and the like, and examples of the organic compound include an alkyl ester, an alcohol compound, a carboxylic acid compound, an ether compound, and a ketone compound. it can.

  In a specific example, as the crosslinking agent, one or more of an isocyanate-based crosslinking agent, a carbodiimide crosslinking agent, and a peroxide-type crosslinking agent may be used. When a peroxide-based crosslinking agent is used, an adhesive layer that does not require aging can be manufactured. In the production process of the pressure-sensitive adhesive layer, a pressure-sensitive adhesive layer that does not require aging is strongly demanded from the viewpoint of improving handling. Therefore, the aging of the pressure-sensitive adhesive layer is not required, which is a great advantage in the manufacturing process. The pressure-sensitive adhesive layer that does not require aging not only has excellent reworkability and reliability, but also has an advantage that handleability during the process of manufacturing the pressure-sensitive adhesive layer is improved.

  The isocyanate-based crosslinking agent is, for example, isocyanate monomer such as tolylene diisocyanate, chlorophenyl diisocyanate, tetramethylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, or the above isocyanate monomer is added with trimethylolpropane or the like. An isocyanurate compound or an isocyanurate burette type compound, and further, a urethane prepolymer type (prepolymer) isocyanate that is subjected to an addition reaction such as a polyether polyol, a polyester polyol, an acrylic polyol, a polybutadiene polyol, and a polyisoprene polyol. It may include one or more of them.

  Specifically, the isocyanate-based crosslinking agent may be a polyisocyanate compound, and more specifically, one or a member selected from the group consisting of hexamethylene diisocyanate, hydrogenated xylylene diisocyanate, and isophorone diisocyanate. It may be a polyisocyanate compound. The hexamethylene diisocyanate, one selected from the group consisting of hydrogenated xylylene diisocyanate and isophorone diisocyanate or a polyisocyanate compound derived therefrom is hexamethylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, polyol-modified hexamethylene diisocyanate, It may contain polyol-modified hydrogenated xylylene diisocyanate, trimer-type hydrogenated xylylene diisocyanate, and polyol-modified isophorone diisocyanate. The above-mentioned polyisocyanate compound may have an excellent rate of a crosslinking reaction with a hydroxyl group. In addition, the exemplified polyisocyanate compound can rapidly promote a crosslinking reaction by using an acid or a base contained in the polymer as a catalyst, and can particularly contribute to speeding up of crosslinking.

  As the carbodiimide-based crosslinking agent, a compound having two or more carbodiimide groups (-N = C = N-) in a molecule may be specifically used, or a known polycarbodiimide compound may be used. The carbodiimide compound may be, for example, a high molecular weight polycarbodiimide produced by subjecting a diisocyanate to a decarboxylation condensation reaction in the presence of a carbodiimidization catalyst. More specifically, the polycarbodiimide compound may be a compound obtained by subjecting the following diisocyanate to a decarboxylation reaction.

  Examples of the diisocyanate used in the polycarbodiimide compound include 4,4′-diphenylmethane diisocyanate, 3,3′-dimethoxy-4,4′-diphenylmethane diisocyanate, 3,3′-dimethyl-4,4′-diphenylmethane diisocyanate, 4,4′-diphenyl ether diisocyanate, 3,3′-dimethyl-4,4′-diphenyl ether diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1-methoxyphenyl-2,4-diisocyanate, One or more of isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and tetramethylxylylene diisocyanate may be used. Further, a mixture of two or more of the above examples may be used.

  At this time, the catalyst used for the carbodiimidization reaction includes 1-phenyl-2-phospholene-1-oxide, 3-methyl-2-phospholene-1-oxide, 1-ethyl-3-methyl-2-phospholene-oxide. Phosphorene oxides such as 1-oxide, 1-ethyl-2-phospholene-1-oxide, or 3-phospholene isomers thereof may be used.

  In a specific example, examples of the high molecular weight polycarbodiimide compound include a carbodilite series manufactured by Nisshinbo Industries, Inc. Among them, when carbodilite V-01, 03, 05, 07, 09 is used, the compatibility with an organic solvent may be excellent.

  Any peroxide-based crosslinking agent can be used without limitation as long as it generates radical active species by heating or light irradiation and promotes crosslinking of the base polymer of the pressure-sensitive adhesive composition. A peroxide-based crosslinker having a half-life temperature of about 50C to about 160C or about 60C to about 140C may be used. In this case, workability and stability can be improved.

  Specifically, as the peroxide-based crosslinking agent, for example, di (2-ethylhexyl) peroxydicarbonate (one minute half-life temperature: about 90.6 ° C.), di (4-t-butylcyclohexyl) peroxy Dicarbonate (1 minute half-life temperature: about 92.1 ° C.), di-sec-butyl peroxydicarbonate (1 minute half-life temperature: about 92.4 ° C.), t-butyl peroxy neodecanoate (1 minute) Min half-life temperature: about 103.5 ° C.), t-hexylperoxypivalate (one-minute half-life temperature: about 109.1 ° C.), t-butyl peroxypivalate (one-minute half-life temperature: about 110. 3 ° C.), dilauroyl peroxide (1 minute half-life temperature: about 116.4 ° C.), di-n-octanoyl peroxide (1 minute half-life temperature: about 117.4 ° C.), 1,1,3, 3-tetra Tylbutylperoxy-2-ethylhexanoate (half-life temperature for one minute: about 124.3 ° C), di (4-methylbenzoyl) peroxide (half-life temperature for one minute: about 128.2 ° C), dibenzoylperoxide Oxide (1 minute half-life temperature: about 130.0 ° C), t-butyl peroxyisobutyrate (1 minute half-life temperature: about 136.1 ° C), 1,1-di (t-hexylperoxy) cyclohexane (1 minute half-life temperature: about 149.2 ° C.). Among them, di (4-t-butylcyclohexyl) peroxydicarbonate (half-life at 1 minute: about 92.1 ° C.) and dilauroyl peroxide (half-minute at 1 minute) are particularly preferable in terms of the crosslinking reaction efficiency. Specific temperature is about 116.4 ° C.), dibenzoyl peroxide (1 minute half-life temperature: about 130.0 ° C.) and the like.

  The peroxide half-life is an index indicating the decomposition rate of peroxide, and refers to the time until the remaining amount of peroxide becomes half. In one specific example, the decomposition temperature and half-life of the peroxide can be as described in, for example, each manufacturer's catalog. For example, the decomposition temperature and half-life of the peroxide are described in “Ninth Organic Oil Catalog 9th Edition (May 2003)” by NOF Corporation.

  The oxazoline-based crosslinking agent is specifically 2-isopropyl-2-oxazoline, 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, It may include one or more of 2-isopropphenyl-2-oxazoline, 2-isopropphenyl-4-methyl-2-oxazoline, and 2-isopropphenyl-5-ethyl-2-oxazoline, but is not limited thereto. . As the oxazoline-based cross-linking agent, a commercially available product may be used. For example, as the oxazoline-based crosslinking agent, an oxazoringi-containing acrylic polymer such as Epocross WS-300, Epocross WS-500, Epocross WS-700, Epocross K-1000 series, Epocross K-2000 series of Nippon Shokubai Co., Ltd. is used alone. Or two or more of them may be used in combination, but the present invention is not limited thereto.

  The amount of the crosslinking agent used may be about 0.01 part by weight to about 20 parts by weight, or about 0.03 part by weight to about 10 parts by weight, based on 100 parts by weight of the adhesive resin. Within the above range, the pressure-sensitive adhesive composition has excellent cohesive strength, can reduce the rate of foaming during heating, has excellent moisture resistance, and can improve reworkability in a reliability test or the like.

  In one specific example, one type of isocyanate-based cross-linking agent may be used alone, or two or more types may be used as a mixture. In such a specific example, the content of the isocyanate-based crosslinking agent is about 0.01 part by weight to about 2 parts by weight, about 0.02 parts by weight to about 2 parts by weight, based on 100 parts by weight of the adhesive resin. It may be from about 0.05 parts to about 1.5 parts by weight. Within the above range, the cohesive strength of the pressure-sensitive adhesive composition, the reworkability in a durability test, and the like can be further improved.

  In another specific example, as the crosslinking agent, one type of peroxide-based crosslinking agent may be used alone, or two or more types may be used in combination. When a peroxide-based crosslinking agent is used, an adhesive layer that does not require aging can be produced. In the production process of the pressure-sensitive adhesive layer, a pressure-sensitive adhesive layer that does not require aging is strongly demanded from the viewpoint of improving handling. Therefore, the aging of the pressure-sensitive adhesive layer is not required, which is a great advantage in the manufacturing process. The pressure-sensitive adhesive layer that does not require aging not only has excellent reworkability and reliability, but also has an advantage that handleability during the pressure-sensitive adhesive layer manufacturing process is improved.

  In such specific examples, the content of the peroxide-based crosslinking agent is about 0.01 parts by weight, 0.02 parts by weight, 0.03 parts by weight, and 0.04 parts by weight based on 100 parts by weight of the adhesive resin. Parts, 0.05 parts by weight, 0.06 parts by weight, 0.07 parts by weight, 0.08 parts by weight, 0.09 parts by weight, 0.1 parts by weight, 0.2 parts by weight, 0.3 parts by weight, 0.4 parts by weight, 0.5 parts by weight, 0.6 parts by weight, 0.7 parts by weight, 0.8 parts by weight, 0.9 parts by weight, 1.0 parts by weight, 1.1 parts by weight, 2 parts by weight, 1.3 parts by weight, 1.4 parts by weight, 1.5 parts by weight, 1.6 parts by weight, 1.7 parts by weight, 1.8 parts by weight, 1.9 parts by weight or 2.0 parts by weight Department. In addition, the content of the peroxide-based crosslinking agent may be in a range of about one or more of the above numerical values and about one or less of the above numerical values with respect to 100 parts by weight of the adhesive resin. . For example, the content of the peroxide-based crosslinking agent is about 0.01 to about 2 parts by weight, specifically about 0.02 to about 2 parts by weight, based on 100 parts by weight of the adhesive resin. And more specifically from about 0.04 parts to about 1.5 parts by weight, and more specifically from about 0.05 parts to about 1 part by weight. Within the above range, the workability, reworkability, crosslinking stability, reworkability, and the like of the pressure-sensitive adhesive composition can be further improved.

  Silane coupling agent

  The pressure-sensitive adhesive composition of one specific example may further contain a silane coupling agent. When a silane coupling agent is used, the durability of the pressure-sensitive adhesive composition can be further improved. Examples of the silane coupling agent include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 2- (3,4-epoxycyclohexyl) Epoxy group-containing silane coupling agents such as ethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N- (1, (Dimethyl butylidene) propylamine, amino group-containing silane coupling agents such as N-phenyl-γ-aminopropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, etc. (Meth) acrylic group Yes silane coupling agent, and the like may be used isocyanate group-containing silane coupling agents such as 3-isocyanate propyltriethoxysilane. The silane coupling agents may be used alone or as a mixture of two or more.

  The content of the silane coupling agent is about 0.001 part by weight to about 10 parts by weight, about 0.001 part by weight to about 5 parts by weight, about 0.01 part by weight based on 100 parts by weight of the above-mentioned adhesive resin. Parts to about 1 part by weight, about 0.02 parts to about 1 part by weight, about 0.05 parts to about 0.6 parts by weight. Within the above range, the durability of the pressure-sensitive adhesive composition can be improved, and the adhesive strength to an optical member such as a liquid crystal cell can be secured.

  Further, the pressure-sensitive adhesive composition of one specific example may further include an additive other than the above-described components. For example, additives include polyalkylene glycol polyether compounds such as polypropylene glycol, colorants, powders such as pigments, dyes, surfactants, plasticizers, tackifiers, surface lubricants, leveling agents, and softeners. , An antioxidant, an antioxidant, a light stabilizer, an ultraviolet absorber, a polymerization inhibitor, an inorganic or organic filler, a metal powder, a particle form, a foil form, and the like may be appropriately added depending on the use. it can. Further, an oxidation-reduction additive to which a reducing agent is added may be used within a controllable range.

  <Formation of adhesive layer and application example of adhesive layer>

  The pressure-sensitive adhesive layer may be formed on various optical films by using the pressure-sensitive adhesive composition in each of the specific examples described above. An optical film on which such an adhesive layer is formed is also referred to as an adhesive optical film. The method for forming the pressure-sensitive adhesive layer is, for example, to apply the pressure-sensitive adhesive composition to a separator (first separator) or the like on which a release agent has been treated, and to form a pressure-sensitive adhesive layer by drying and removing a polymerization solvent and the like. A method of transferring this to an optical film; or a method of applying the pressure-sensitive adhesive composition to the optical film and removing the polymerization solvent by drying to form a pressure-sensitive adhesive layer on the optical film may be used. When applying the pressure-sensitive adhesive composition, one or more solvents other than the polymerization solvent may be newly added.

  As the separator, for example, a silicone liner may be specifically used. Such a liner may be, for example, one in which a silicone-based release agent is treated on one surface of the liner. Such a silicone-based release agent can facilitate the transfer of the pressure-sensitive adhesive composition formed on the separator to the optical film.

  A specific method of forming the pressure-sensitive adhesive layer may include a method of applying the pressure-sensitive adhesive composition on a separator or an optical film to form a coating film. After the formation of the coating film, a method of heating and drying the coating film may be included. The heat drying temperature is from about 40C to about 200C, specifically from about 50C to about 180C, and more specifically from about 70C to about 170C. By setting the heating temperature within the above range, a pressure-sensitive adhesive composition having excellent pressure-sensitive adhesive properties can be obtained.

  An appropriate drying time can be adopted. The drying time may be, for example, from about 5 seconds to about 20 minutes, more specifically, from about 5 seconds to about 10 minutes, and particularly, from about 10 seconds to about 5 minutes.

  In one specific example, when applying the pressure-sensitive adhesive composition to the surface of the optical film, the surface of the optical film, the formation treatment for the anchor layer, corona treatment, after performing various easy adhesion treatment such as plasma treatment, the pressure-sensitive adhesive layer (Adhesion auxiliary layer). Further, the surface of the adhesive layer may be subjected to an easy adhesion treatment.

  The method for applying the pressure-sensitive adhesive composition is not particularly limited, and examples thereof include a roll coat, a kiss roll coat, a gravure coat, a reverse coat, a roll brush, a spray coat, a deep roll coat, a bar coat, a knife coat, an air knife coat, and a curtain. Examples of the method include an extrusion coating method using a coat, a lip coat, a die coat, and the like.

  A crosslinking treatment can be performed at the time of forming the adhesive layer. Such a crosslinking treatment may be performed at the temperature at the time of the drying step of the adhesive layer, or may be performed by providing a separate crosslinking processing step after the drying step. The cross-linking treatment can adjust the addition amount of the whole cross-linking agent and sufficiently consider the influence of the cross-linking temperature and the cross-linking time.

  Specifically, the crosslinking temperature and the crosslinking time can be adjusted depending on the crosslinking agent used. In one embodiment, the temperature of the cross-linking treatment during the formation of the pressure-sensitive adhesive composition may be about 170 ° C. or less, specifically about 130 ° C. or less. Within the above range, the energy efficiency at the time of forming the adhesive layer can be improved. Further, when a specific separator (eg, PET) is used as a base material for forming an adhesive layer, there is an advantage that generation of foreign substances such as oligomers can be suppressed. The foreign matter (eg, oligomer) may be generated at 30 ppm or less, specifically, 10 ppm or less. Within the above range, the foreign matter is suitable for use as an adhesive for an optical film.

  Further, the cross-linking time can be set in consideration of productivity and workability. In one embodiment, the time of the crosslinking treatment at the time of forming the pressure-sensitive adhesive composition may be about 0.2 minutes to about 20 minutes, or about 0.5 to about 10 minutes.

  In one specific example, the adhesive layer can be formed by performing a peroxide crosslinking treatment with a peroxide-based crosslinking agent at the time of the crosslinking treatment.

  The pressure-sensitive adhesive layer includes a pressure-sensitive adhesive resin including at least one of a (meth) acrylic polymer, a urethane polymer, and a polyester, a silicate oligomer represented by the following Chemical Formula 1, and a peroxide-based crosslinking agent. A pressure-sensitive adhesive layer formed by the cross-linking treatment at a temperature of 23 ° C. and a humidity of 65% RH for 1 hour after the formation of the pressure-sensitive adhesive layer, and having a gel fraction of about 40 wt% to about 95 wt. % By weight.

  [Formula 1]

In the chemical formula 1, R _{1 to} R ₄ are each independently hydrogen, an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and X ₁ and X ₂ are each independently Hydrogen, an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and n is an integer of 1 to 100.

  [Equation 1]

  Gel fraction (% by weight) = {(Wc−Wa) / (Wb−Wa)} × 100

  In the above formula 1, Wb is the weight when 0.2 g of the adhesive layer is covered with a fluororesin (TEMISHNTF-1122, Nitto Denko Corporation), and Wa is the weight of the fluororesin. Further, Wc extracts the soluble component by immersing the adhesive layer covered with the fluororesin in 40 ml of ethyl acetate at about 23 ° C. for about 7 days to extract a soluble component. This is the weight of the adhesive layer covered with a fluororesin from which the soluble matter has been removed after drying at 130 ° C. for about 2 hours.

  When the pressure-sensitive adhesive composition forms a pressure-sensitive adhesive layer by peroxide crosslinking treatment, the gel fraction after about 1 hour is about 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%. %, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80% , 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94% or 95%. . Further, the gel fraction after one hour may be in a range of one or more of the numerical values and one or less of the numerical values. For example, when the pressure-sensitive adhesive composition forms a pressure-sensitive adhesive layer by peroxide crosslinking, the gel fraction after about 1 hour is about 40% to about 95% by weight, specifically about 65% to about 95% by weight. % Range can be satisfied. Within the above range, the pressure-sensitive adhesive layer has the advantage of excellent workability since there is no fear of a pressing phenomenon and a decrease in durability, and aging is not required.

  As the peroxide crosslinking treatment time, a half-life time or more corresponding to the peroxide crosslinking treatment temperature (about 170 ° C. or less, specifically about 130 ° C. or less) may be used for the peroxide crosslinking treatment.

  The adhesive resin has an acid value of about 0 mgKOH / g, 0.1 mgKOH / g, 0.2 mgKOH / g, 0.3 mgKOH / g, 0.4 mgKOH / g, 0.5 mgKOH / g, 0.6 mgKOH / g, 0.7 mg KOH / g, 0.8 mg KOH / g, 0.9 mg KOH / g, 1.0 mg KOH / g, 1.1 mg KOH / g, 1.2 mg KOH / g, 1.3 mg KOH / g, 1.4 mg KOH / g, 1. It may be 5 mgKOH / g, 1.6 mgKOH / g, 1.7 mgKOH / g, 1.8 mgKOH / g, 1.9 mgKOH / g, 2.0 mgKOH / g. Further, the adhesive resin may have an acid value in a range of at least one of the above-mentioned numerical values and one or less of the above-mentioned numerical values. For example, the acid value of the adhesive resin is about 0 mgKOH / g to about 20.0 mgKOH / g, specifically about 0 mgKOH / g to about 10.0 mgKOH / g, more specifically about 0 mgKOH / g to about 5.0 mgKOH. / G, more specifically from about 0 mg KOH / g to about 3.0 mg KOH / g. Within the above range, the pressure-sensitive adhesive composition has excellent adhesive strength and reliability, and can be balanced with reworkability.

  The composition contains a peroxide-based crosslinking agent, and can form an adhesive layer by peroxide crosslinking treatment.

  In the peroxide crosslinking treatment, about 50% by weight or more of the peroxide crosslinking agent can be decomposed. By decomposing 50% by weight or more of the peroxide-based crosslinking agent, the gel fraction of the adhesive layer can be made about 40% by weight to about 95% by weight.

  The pressure-sensitive adhesive layer may have a difference between the initial adhesive strength and the adhesive strength after heating of 1 N / 25 mm or less. Within the above range, the reworkability and reliability of the adhesive layer are excellent.

  The initial adhesive force is the adhesive force to the following initial glass plate, the adhesive force after heating is the adhesive force to the following heated glass plate, and the initial glass plate and the heated glass plate are as follows. To produce.

  An adhesive type polarizing film (sample) is cut into a width of 25 mm and a length of 100 mm, and is attached to a non-alkali glass plate (Eagle XG, manufactured by Corning Co., Ltd.) having a thickness of 0.5 mm using a laminator. Next, the polarizing film is completely adhered to the alkali-free glass by subjecting the glass plate with the polarizing film to autoclave treatment at about 50 ° C. and 5 atm for 15 minutes. Thus, an initial glass plate is manufactured. Then, the initial glass plate is heated for 48 hours under a drying condition of 50 ° C. to produce a heated glass plate. Then, the adhesion between the initial glass plate and the heated glass plate is measured by the following method.

  The adhesive strength (N / 25 mm) when peeling the polarizing film from each glass plate is measured using a tensile tester (Orientec Co., Ltd. product, Tensilon Universal Material Tester STA-1150). The measurement conditions are about 23 ° C., a relative humidity of about 50%, a peel angle of about 180 °, and a peel rate of about 300 mm / min. Peeling is performed according to the method of testing an adhesive tape and an adhesive sheet according to JIS Z0237.

  The adhesive layer may have an adhesive strength after heating of about 3 N / 25 mm or less, specifically about 2.5 N / 25 mm or less. Within the above range, the reworkability and reliability of the adhesive layer are excellent.

  The thickness of the adhesive layer is not particularly limited, but may be, for example, about 1 μm to about 100 μm, specifically, about 2 μm to about 50 μm, more specifically, about 2 μm to about 40 μm, and more specifically. Specifically, it is about 5 μm to about 35 μm. Within the above range, the adhesive strength of the pressure-sensitive adhesive layer and the reworkability can be effectively compatible.

  When the surface of the pressure-sensitive adhesive layer must be exposed during storage, the pressure-sensitive adhesive layer can be protected by further forming a release agent-treated separator (second separator). Such a second separator is removed and used when the adhesive layer is applied.

  <Adhesive optical film>

  The pressure-sensitive adhesive optical film of the present invention may include an optical film and the pressure-sensitive adhesive layer formed on one or both surfaces of the optical film.

  As the optical film, a film used for forming an image display device such as a liquid crystal display device is used, and the type thereof is not particularly limited. For example, a polarizer can be mentioned as an optical film. Specifically, the adhesive optical film includes a polarizer, a protective layer formed on one surface of the polarizer, and an adhesive layer formed on the other surface of the polarizer. It may be formed of a pressure-sensitive adhesive composition for a film.

  The polarizer may include a transparent protective film on at least one surface of the polarizer. The polarizer is not particularly limited, for example, a polyvinyl alcohol-based film, a partially foamed polyvinyl alcohol-based film, a hydrophilic polymer film such as an ethylene-vinyl acetate copolymer-based partially saponified film, a different color of iodine or a heterochromatic dye. And uniaxially stretched by adsorbing a hydrophilic substance, and a polyene-based oriented film such as a dehydrated product of polyvinyl alcohol or a dehydrochlorination product of polyvinyl chloride. In a specific example, a polarizer made of a heterochromatic substance such as a polyvinyl alcohol-based film and iodine may be used as the polarizer. In this case, the optical degree and handleability of the polarizing film may be further improved. The thickness of the polarizer is not particularly limited, but may be, for example, about 5 μm to about 80 μm.

  The protective layer is not limited as long as it can protect the polarizer. Specifically, the protective layer may be a transparent protective film. The transparent protective film may be bonded to one or both sides of the polarizer by an adhesive layer. An adhesive is used for the bonding between the polarizer and the transparent protective film. Examples of the adhesive include an isocyanate-based adhesive, a polyvinyl alcohol-based adhesive, a gelatin-based adhesive, a vinyl latex-based adhesive, and a water-based polyester. The adhesive is usually used as an adhesive composed of an aqueous solution, and may contain, for example, about 0.5% to about 60% by weight of solids. In addition, examples of the adhesive between the polarizer and the transparent protective film include an ultraviolet curable adhesive and an electron beam curable adhesive. The electron beam-curable adhesive for polarizing films exhibits appropriate adhesiveness to the various transparent protective films. In one specific example, the adhesive for bonding the polarizer and the transparent protective film may further include a metal compound filler.

  As a material constituting the transparent protective film, for example, a thermoplastic resin excellent in transparency, mechanical strength, heat stability, moisture barrier property, isotropy, and the like is used. Specific examples of such thermoplastic resins include cellulose resins such as triacetyl cellulose, polyester resins, polyether sulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth) acrylic resins, and cyclic resins. Examples include polyolefin resins (norbornene-based resins), polyarylate resins, polystyrene resins, polyvinyl alcohol resins, and mixtures thereof. On one side of the polarizer, a transparent protective film is bonded by an adhesive layer, while on the other side, a (meth) acrylic, urethane, acrylic urethane, epoxy, silicone A thermosetting resin such as a system or an ultraviolet curable resin may be used. The transparent protective film may contain one or more optional additives. Examples of the additive include an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a release agent, a coloring inhibitor, a flame retardant, a nucleating agent, an antistatic agent, a pigment, and a coloring agent. The content of the thermoplastic resin in the transparent protective film is, specifically, about 50% to about 100% by weight, more specifically, about 50% to about 99% by weight, and more specifically, about 60% by weight. % To about 98%, particularly from about 70% to about 97% by weight. If the content of the thermoplastic resin in the transparent protective film is 50% by weight or less, the high transparency inherent in the thermoplastic resin may not be sufficiently exhibited.

  The thickness of the transparent protective film can be determined as appropriate, but is generally about 1 μm to about 500 μm in terms of workability such as strength and handleability and thin layer property, and particularly about 1 μm to about 300 μm and about 5 μm. ２００200 μm. In particular, the adhesive layer of one specific example is suitable for directly forming the adhesive layer on a thin transparent protective film having a thickness of about 40 μm or less.

  In another embodiment, the protective layer may be a protective coating layer. The protective coating layer can be formed of an active energy ray-curable resin composition containing an active energy ray-curable compound and an initiator. The active energy ray-curable compound may include at least one of an acrylic compound, an epoxy compound, and an isocyanurate compound.

  The protective coating layer may have a thickness of about 5 μm to about 200 μm, specifically about 5 μm to about 20 μm, and more specifically about 4 μm to about 10 μm. Within the above range, the protective coating layer can be formed directly on the polarizer without using an adhesive, and the thickness of the polarizing plate can be reduced.

  Further, the pressure-sensitive adhesive optical film can be laminated with another optical film. Other optical films include, for example, liquid crystal display devices such as a reflection plate, a semi-transmission plate, a retardation film (including a wavelength plate such as 1/2 or 1/4), a visual compensation film, and a brightness enhancement film. And an optical layer which may be used in the above. These may be laminated on the polarizing film at the time of practical use, and one layer or two or more layers may be used. For example, the pressure-sensitive adhesive optical film may further include a retardation film formed on the pressure-sensitive adhesive layer.

  The optical film obtained by laminating the optical layer on the adhesive optical film can be formed by a method of sequentially laminating the optical film in a manufacturing process of a liquid crystal display device or the like. It is advantageous in that the manufacturing process of a liquid crystal display device or the like can be improved because of its excellent workability and assembly work. For the lamination, an appropriate bonding means such as an adhesive layer can be used. When the polarizing film is bonded to another optical layer, the optical axes thereof can be set at an appropriate arrangement angle according to the target retardation characteristics and the like.

  A polarizer obtained by dyeing a polyvinyl alcohol-based film with iodine and uniaxially stretching the dye is, for example, dyeing polyvinyl alcohol by immersing it in an aqueous solution of iodine and stretching the film to 3 to 7 times its original length. can do. If necessary, polyvinyl alcohol may be immersed in an aqueous solution of potassium iodide or the like that may contain boric acid, zinc sulfate, zinc chloride, or the like. If necessary, the polyvinyl alcohol-based film may be immersed in water and washed with water before dyeing. Washing the polyvinyl alcohol-based film with water has the effect of preventing contamination of the surface of the polyvinyl alcohol-based film and the antiblocking agent, and also has the effect of preventing unevenness such as uneven dyeing by swelling the polyvinyl alcohol-based film. Stretching may be performed after dyeing with iodine, may be performed while dyeing, or may be dyed with iodine after stretching. Stretching can be carried out in an aqueous solution of boric acid or potassium iodide or in a water bath.

  Examples of the optical film include liquid crystal displays such as a reflection plate, a semi-transmission plate, a retardation film (including a wavelength plate such as 1/2 or 1/4), a visual compensation film, a brightness enhancement film, and a surface treatment film. An example of an optical layer that may be used for forming a device or the like can be given. These may be used alone as an optical film, or may be laminated on the polarizing film at the time of practical use, and one or more layers may be used. For example, the optical film including the optical film and the adhesive layer may further include a retardation film formed on the adhesive layer.

  Although the thickness of the various optical films listed above is not particularly limited, the pressure-sensitive adhesive composition according to one specific example has a reworking property for the optical film even when the optical film is thin (for example, about 100 μm or less). High reliability while securing. Further, an adhesion auxiliary layer may be formed on the optical film, and an adhesive layer may be formed on the adhesion auxiliary layer. The adhesion assisting layer is a layer having greater wettability to the adhesive layer than the optical film. The adhesion auxiliary layer is manufactured by, for example, corona treatment for an optical film. An adhesion auxiliary layer may be separately prepared and attached to an optical film. Specifically, the adhesion auxiliary layer may be formed on at least one of the optical film surface and the adhesive layer surface. By forming the adhesion auxiliary layer, the adhesive layer can be easily formed on the optical film.

  1 and 2 show examples of an adhesive optical film. The adhesive type optical film 10 shown in FIG. 1 includes an optical film 11 and an adhesive layer 12 formed on one surface of the optical film 11. As described above, the adhesive layer 12 is formed on the optical film 11 by, for example, applying a solution of the adhesive composition to one surface of the optical film 11 and then removing the solvent. The optical film 11 may be, for example, a polarizer. Thus, the pressure-sensitive adhesive composition may be used as a pressure-sensitive adhesive layer formed in advance on an optical film. Further, the adhesive layers 12 may be formed on both surfaces of the optical film 11. FIG. 2 shows a modified example of the pressure-sensitive adhesive optical film 10. The adhesive optical film 10 shown in FIG. 2 has an adhesion auxiliary layer 11a formed between the optical film 11 and the adhesive layer 12. The adhesion auxiliary layer 11 a is a layer having greater wettability to the adhesive layer 12 than the optical film 11.

  The display device of the present invention may include the adhesive optical film. Examples of the display device include a liquid crystal display device and an organic electroluminescence display device.

  3 and 4 show a configuration example of a display device having a pressure-sensitive adhesive layer according to a specific example. The display device 20 shown in FIG. 3 includes a display element 21, an adhesive layer 22, and an optical film 23. The optical film 23 is disposed on both sides of the display element 21, and the adhesive layer 22 bonds the display element 21 to the optical film 23. The display device 20 may be manufactured by attaching an adhesive optical film including an adhesive layer 22 and an optical film 23 to both surfaces of the display element 21. Alternatively, an adhesive layer 22 may be formed on both surfaces of the display element 21, and the optical film 23 may be attached to the adhesive layer 22.

  FIG. 4 is a modified example of the display device 20. As shown in FIG. 4, a plurality of optical films may be provided on the display element 21. In the display device 20 shown in FIG. 4, the adhesive layer 24 and the optical film 25 are further provided on the optical film 23 of the display device 20 shown in FIG. The adhesive layer 24 and the optical film 25 are set on the optical film 23 in the same manner as the adhesive layer 22 and the optical film 23.

  As described above, the display device 20 may be, for example, a liquid crystal display device, an organic EL display device, or the like. When the display device 20 is a liquid crystal display device, the display element 21 is a liquid crystal cell, and the optical film 23 is a polarizing film. The optical film 25 is, for example, a viewing angle widening film, a brightness enhancement film, various protective films, and the like. When the display device 20 is a liquid crystal display device, a retardation plate may be provided between the adhesive layer 22 and the display element 21. Further, the retardation plate and the display element 21 may be bonded by an adhesive layer. Although the thickness of the display element 21 is not particularly limited, the pressure-sensitive adhesive composition according to one specific example ensures reworkability with respect to the display element 21 even when the display element 21 is thin (for example, 200 μm or less). Has high reliability. In other words, the pressure-sensitive adhesive composition according to one specific example has high reliability while ensuring reworkability even when one or both of the optical film and the display element is thin.

  <Adhesive layer manufacturing method>

  The method for producing a pressure-sensitive adhesive layer of the present invention includes a step of forming a pressure-sensitive adhesive layer on one or both surfaces of a substrate with a pressure-sensitive adhesive composition for an optical film, wherein the pressure-sensitive adhesive composition for an optical film has an acid value of about 0 mgKOH / g. And about 20.0 mg KOH / g, and a silicate oligomer represented by Formula 1 below.

  [Formula 1]

In the chemical formula 1, R _{1 to} R ₄ are each independently hydrogen, an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and X ₁ and X ₂ are each independently Hydrogen, an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and n is an integer of 1 to 100. Specifically, R _{1 to} R ₄ are each independently an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, and X ₁ and X ₂ are each independently hydrogen, carbon, It may be an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms. For example, R _{1 to} R ₄ may be a methyl group, an ethyl group, or a phenyl group.

  The substrate may be an optical film. As the optical film, a film used for forming an image display device such as a liquid crystal display device is used, and the type thereof is not particularly limited. The optical film is substantially the same as that described for the adhesive layer. For example, a polarizing film can be mentioned as an optical film.

  The step of forming the pressure-sensitive adhesive layer includes forming a layer containing the pressure-sensitive adhesive composition for an optical film on one or both surfaces of a substrate, and peroxide crosslinking the layer containing the pressure-sensitive adhesive composition for the optical film. The method may include performing a process.

  During the production of the adhesive layer, a peroxide crosslinking treatment can be performed. Such a crosslinking treatment is substantially the same as that described in the process of forming the adhesive layer. Specifically, the peroxide crosslinking treatment decomposes the peroxide crosslinking agent by about 50% by weight or more, C. or lower, and the gel fraction of the adhesive layer may be about 40% to about 95% by weight.

  In one specific example, the pressure-sensitive adhesive composition for an optical film contains about 0.01 parts by weight to about 2 parts by weight of a peroxide-based crosslinking agent with respect to about 100 parts by weight of an adhesive resin, and contains about 0.02 parts by weight. It may further include from about 2 parts by weight to about 2 parts by weight, from about 0.04 parts by weight to about 1.5 parts by weight, from about 0.05 parts by weight to about 1 part by weight.

  In another embodiment, the pressure-sensitive adhesive composition for an optical film comprises about 0.01 parts by weight to about 50 parts by weight of a silicate oligomer per 100 parts by weight of a pressure-sensitive adhesive resin, specifically, about 0.5 parts by weight or more. It may contain about 20 parts by weight, more specifically about 0.5 parts to about 10 parts by weight, and more specifically about 1 part to about 5 parts by weight. Within the above range, the initial reworkability and the adhesive strength after heating of the pressure-sensitive adhesive composition can be further improved.

  In still another embodiment, the pressure-sensitive adhesive composition for an optical film may further include a crosslinking agent. Examples of the crosslinking agent include, but are not limited to, isocyanate-based crosslinking agents, carbodiimide crosslinking agents, oxazoline-based crosslinking agents, peroxide-based crosslinking agents, epoxy-based crosslinking agents, and imine-based crosslinking agents.

  Next, an example of one specific example will be described. In the following examples, the concentration of the solution is shown in% by weight based on the total weight of the solution.

  [Example]

  <A. Example for Reworkability and Reliability Evaluation>

  The reworkability and reliability of the pressure-sensitive adhesive layer were evaluated by the following Examples and Comparative Examples.

  Production Example 1 (Production example of acrylic resin)

  An acrylic resin (polymer A1), which is an example of an adhesive resin, was manufactured through the following steps. In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser, 99 parts by weight of butyl acrylate, 1 part by weight of 4-hydroxybutyl acrylate, and 2,2′-azobisisobutyro as a polymerization initiator. 0.15 parts by weight of nitrile were injected along with 100 parts by weight of ethyl acetate. Then, while gently stirring the mixed solution, nitrogen gas was introduced into the four-necked flask to perform nitrogen replacement. Thereafter, the liquid temperature in the flask was maintained at around 55 ° C., and the monomers were allowed to undergo a polymerization reaction for 5 hours. This produced a solution of polymer A1. The weight average molecular weight (Mw) of the polymer A1 was 2.1 million. Further, the acid value of the polymer A1 was 0 mgKOH / g. Table 1 shows the composition of the polymer A1 (weight ratio of the monomers constituting the polymer A1), the weight average molecular weight, and the acid value.

  Here, the weight average molecular weight of the polymer A1 was measured by GPC (gel permeation chromatography). The measuring device and the measuring conditions are as follows.

  Analyzer: Tosoh Corporation product, HLC-8120GPC

  Column: Tosoh Corporation product, G7000HXL + GMHXL + GMHXL

  Column size: 7.8mmφ × 30cm each, 90cm in total

  Column temperature: 40 ° C

  Flow rate: 0.8ml / min

  Injection volume: 100 μl

  Eluent: tetrahydrofuran

  Detector: Time difference refractometer (RI)

  Standard sample: polystyrene

  The acid value of the polymer A1 was measured by the following steps. A mixed solvent containing toluene, isopropyl alcohol and distilled water in a weight ratio of 50: 49.5: 0.5 was prepared. Next, about 0.5 g (solid content basis) of the polymer A1 was precisely weighed and dissolved in 50 g of the mixed solvent. Thereby, a sample solution for titration was prepared. This sample solution was subjected to neutralization titration with a 0.1N KOH aqueous solution using a titration apparatus manufactured by Hiranuma Sangyo Co., Ltd., model “COMTITE-550”. The acid value of the polymer A1 was calculated from the obtained result and the following [Equation 2].

  [Equation 2]

  Acid value [mgKOH / g] = (ab) × 5.611 × F / S

  In Equation 2,

  a: Amount of KOH aqueous solution necessary for titration of sample solution [ml]

  b: Amount of KOH aqueous solution necessary for titration of blank (mixed solvent) [ml]

  F: Potency of KOH aqueous solution

  S: Weight of resin contained in sample solution provided for titration [g]

  It is.

  Production Examples 2 to 7 (Production examples of acrylic resin)

  Polymers A2 to A6 were produced by performing the same steps as in Production Example 1 except that the types and weight ratios of the monomers charged into the four-necked flask were changed as shown in Table 1. Further, the weight average molecular weights and the acid values of the polymers A2 to A7 were measured by the same methods as in Production Example 1. The results are summarized in Table 1.

  Production Example 8 (Example of producing urethane resin)

  A urethane resin (polymer A8) was manufactured by the following steps. In a four-necked flask equipped with a stirrer, a reflux condenser, a nitrogen inlet, a thermometer, and a dropping funnel, 51.9 g of polyester polyol P-1010 (two-action polyester polyol, OH value 112 mg / g, Kuraray Co., Ltd.), Adeka 32.2 g of polyether (Adeka polyether) G-1500 (trifunctional polyether poly, trifunctional, OH value 109 mg / g, product of ADEKA Corporation), isophorone diisocyanate (IPDI) (product of Sumitomo Bayer Urethane Co., Ltd.) 15 9.9 g, 66.7 g of toluene, 0.03 g of iron 2-ethylhexanoate, and 0.04 g of lead naphthenate were charged as a catalyst.

  Next, the temperature of the mixed solution was gradually increased to 90 ° C., and the monomers were polymerized for 4 hours. The residual isocyanate group was confirmed by an infrared spectrophotometer (IR), and the reaction was terminated at the timing when the peak corresponding to the isocyanate group disappeared, and the mixed solution after the reaction, that is, the urethane resin solution was cooled. The urethane resin solution was colorless and transparent, and had a solid content of 60% by weight. The weight average molecular weight and the acid value were measured in the same manner as in Production Example 1. As a result, the weight average molecular weight was 50,000, and the acid value was 0.5 KOHmg / g. Table 2 shows the composition of polymer A8 (weight ratio of the monomers constituting polymer A8), the weight average molecular weight, and the acid value.

  Production Example 9 (Production example of polyester resin)

  A polyester resin (polymer A9) was produced by the following steps. In a four-neck separable flask equipped with a thermometer, a stirrer, a distillation tube, and a condenser, 11.7 g of ethylene glycol, 18.6 g of neopentyl glycol, 11.8 g of isophthalic acid, 57.9 g of sebacic acid and tetra-n- 0.15 g of butyl titanate was charged. Thereafter, the esterification reaction is carried out by heating the mixed solution at 150 ° C. to 270 ° C. for 150 minutes. Subsequently, the pressure of the reaction system is gradually reduced to 133 Pa after 30 minutes, and 180 minutes while continuing the reduced pressure. The reaction was performed. Next, the solution of the polyester resin was obtained by diluting the mixed solution after the reaction with ethyl acetate. The solids content of this solution was 60% by weight. The weight average molecular weight and the acid value of the polyester resin were measured by the same methods as in Production Example 1, and as a result, the weight average molecular weight was 38,000 and the acid value was 0.3 KOHmg / g. Table 3 shows the composition of polymer A9 (the weight ratio of the monomers constituting polymer A8), the weight average molecular weight, and the acid value.

  The component contents in Tables 1 to 3 are shown in parts by weight.

  Production Example 10 (Production example of high molecular weight type)

Through the following steps, a high molecular weight type silicate oligomer B1 was produced. 152 g (1 mol, 4 equivalents) of tetramethoxysilane was dissolved in 500 g of tetrahydrofuran (hereinafter, also referred to as "THF"). Next, 72 g (8 equivalents) of a 0.35% by weight aqueous hydrochloric acid solution was added to the obtained solution and mixed. Next, the tetramethoxysilane was hydrolyzed by leaving the mixed solution at 20 ° C. for 1 hour. Next, reflux was performed for 2 hours by adding 450 g of polymethoxysiloxane (“MKC silicate MS-51” manufactured by Mitsubishi Chemical Corporation) to the solution after hydrolysis, that is, the reaction solution. Thereafter, THF was allowed to flow out by increasing the temperature of the reaction solution to 150 ° C. As a result, a silicate oligomer B1 which was colorless and transparent and was in liquid form was obtained. The weight average molecular weight of the silicate oligomer B1 was 25,000. The raw material polymethoxysiloxane (“MKC silicate MS-51”) is an oligomer having a weight average molecular weight of 900. Therefore, a high molecular weight silicate oligomer was produced by bonding the hydrolyzed tetramethoxysilane and polymethoxysiloxane. R _{1 to} R ₄ , X ₁ and X ₂ of the silicate oligomer B1 are represented by Formula 1 in which all are methyl groups.

  The weight average molecular weight of the silicate oligomer B1 was measured by GPC (gel permeation chromatography).

  The measuring device and the measuring conditions are as follows.

  Analyzer: Tosoh Corporation product, HLC-8120GPC

  Column: TSKgel, SuperHZM-H / HZ4000 / HZ2000

  Column size: 6.0mm (inner diameter) x 150mm

  Column temperature: 40 ° C

  Flow rate: 0.6 ml / min

  Injection volume: 20 μl

  Eluent: tetrahydrofuran

  Detector: Time difference refractometer (RI)

  Standard sample: polystyrene

  Production Example 11 (Production example of phenoxy type)

The silicate oligomer B2 in which R _{1 to} R ₄ , X ₁ and X ₂ are a phenyl group or a methyl group (R _{1 to} R ₄ , X ₁ or X ₂ contains a phenyl group) in Chemical Formula 1 by the following steps. Was made. 400 g (1 mol, 4 equivalents) of tetraphenoxysilane was dissolved in 500 g of THF. Next, 72 g (8 equivalents) of a 0.35% by weight aqueous hydrochloric acid solution was added to the obtained solution and mixed. Next, the mixed solution was left at 20 ° C. for 1 hour to hydrolyze tetraphenoxysilane. Next, reflux was performed for 2 hours by adding 450 g of polymethoxysiloxane (“MKC silicate MS-51” manufactured by Mitsubishi Chemical Corporation) to the solution after hydrolysis, that is, the reaction solution. Thereafter, THF was allowed to flow out by increasing the temperature of the reaction solution to 150 ° C. Thus, a silicate oligomer B2 in a colorless and transparent liquid form was obtained. As a result of measuring the weight average molecular weight of the silicate oligomer B2 in the same manner as in Production Example 10, the weight average molecular weight of the silicate oligomer B2 was 5,000. The raw material polymethoxysiloxane (“MKC silicate MS-51”) is an oligomer having a molecular weight of 900. Therefore, by bonding the hydrolyzed tetraphenoxysilane and polymethoxysiloxane, silicate oligomer B2 in which R _{1 to} R ₄ , X ₁ and X ₂ are phenyl groups or methyl groups was generated.

  In addition, the present inventor obtained some silicate oligomers in addition to the above, and provided them to the following experiments.

  Optical film manufacturing example

  Production Example 12 (One-sided protective polarizing film)

  A single-sided protective polarizing film was produced as an optical film by the following steps. A polyvinyl alcohol film having a thickness of 20 μm was stretched up to 3 times while being dyed in a 0.3% by weight iodine solution at 30 ° C. for 1 minute between rolls having different speed ratios. Thereafter, the stretched film was stretched to a total stretch ratio of 6 while immersing in an aqueous solution containing 4% by weight of boric acid and 10% by weight of potassium iodide for 0.5 minute at 60 ° C. Next, the stretched film was washed by being immersed in an aqueous solution containing 1.5% by weight of potassium iodide at 30 ° C. for 10 seconds, and then dried at 50 ° C. for 4 minutes. Thus, a polarizer was obtained. Then, an acrylic film (lactone-modified acrylic resin film) having a thickness of 20 μm was bonded to one surface of the polarizer with a polyvinyl alcohol-based adhesive. An acrylic film is an example of a protective film. Thus, a single-sided protective polarizing film having a total thickness of 27 μm was produced.

  <Example 1>

  Production of adhesive composition

  With respect to 100 parts by weight of the solid content of the polymer A1 solution obtained in Production Example 1, as silicate oligomer B, 5 parts by weight of methyl silicate 51 (weight average molecular weight 550) manufactured by Colcoat Co., Ltd., and an isocyanate-based crosslinking agent Takenate D110N 0.1% by weight of a 75% by weight solution of xylylene diisocyanate adduct of trimethylolpropane in ethyl acetate, 3 isocyanate groups in one molecule, manufactured by Mitsui Chemicals, Inc., and a silane coupling agent (trade name: KBM) -403, product of Shin-Etsu Chemical Co., Ltd., 3-glycidoxypropyltrimethoxysilane) 0.1 part by weight. Thus, a pressure-sensitive adhesive composition solution (solid content 15% by weight) was obtained. Table 4 shows the composition of the pressure-sensitive adhesive composition.

  Production of adhesive polarizing film (adhesive optical film)

The adhesive composition solution was coated on one side of a silicone-treated 38 μm-thick polyethylene terephthalate (PET) film (manufactured by Mitsubishi Chemical Polyester Film Co., Ltd., MRF38, without an oligomer preventing layer), and the thickness of the dried adhesive layer was Was applied so as to be 20 μm. Next, the coating layer was dried at 100 ° C. for 2 minutes to form an adhesive layer. Bonding the pressure-sensitive adhesive layer to the polarizer surface (corona-treated surface) that has been subjected to corona treatment with a corona discharge amount of 80 [W · min / m ² ] with respect to the one-sided protective polarizing film produced in Production Example 12. Thus, an adhesive type polarizing film was manufactured.

  Examples 2 to 22, Comparative Examples 1 to 8

  Except that the composition of the adhesive resin was changed to the composition shown in Tables 4, 5 and 6, an adhesive polarizing film was produced by performing the same treatment as in Example 1.

In Tables 4, 5 and 6, the silicate oligomer B3 is methyl silicate 51 in which R _{1 to} R ₄ , X ₁ and X ₂ are all methyl groups and the weight average molecular weight is 600. The silicate oligomer B4 is methyl silicate 53A (a product of Colcoat Co., Ltd.) in which R _{1 to} R ₄ , X ₁ and X ₂ are all methyl groups and the weight average molecular weight is 900. The silicate oligomer B5 is a MKC silicate MS58B15 (Mitsubishi Chemical Co., Ltd.) in which R _{1 to} R ₄ , X ₁ and X ₂ are butyl groups (15%), the remainder is methyl groups (85%), and the weight average molecular weight is 3,200. Co., Ltd.). The silicate oligomer B6 is EMS-485 (product of Colcoat Co., Ltd.) in which R _{1 to} R ₄ , X ₁ and X ₂ are a methyl group (50%) and an ethyl group (50%), and have a weight average molecular weight of 1,300. It is. The silicate oligomer B7 is ethyl silicate 48 (a product of Colcoat Co., Ltd.) in which R _{1 to} R ₄ , X ₁ and X ₂ are all ethyl groups and the weight average molecular weight is 1,400.

  Parloyl TCP is a peroxide-based cross-linking agent manufactured by NOF CORPORATION.

  <Physical property evaluation method>

  (1) Reliability evaluation test

  A reliability evaluation test was performed on the adhesive polarizing film (adhesive optical film) according to each of the examples and comparative examples. Specifically, the adhesive polarizing film (sample) was cut into a 37-inch size (56.4 cm long × 75.2 cm wide), and a 0.5 mm thick alkali-free glass (Corning Corporation) Product, Eagle XG) using a laminator (laminating machine). The non-alkali glass is used as a liquid crystal cell glass substrate. In addition, a liquid crystal cell to which two pieces of non-alkali glass having a thickness of 0.25 mm are attached is used for an actual liquid crystal cell. Then, in the present test and the evaluation of adhesive strength and reworkability described later, an adhesive polarizing film is attached to both surfaces of such non-alkali glass. Therefore, the fact that these characteristics are excellent means that the pressure-sensitive adhesive type polarizing film can be appropriately used as a polarizing film of a liquid crystal cell.

  Subsequently, the sample was completely adhered to the alkali-free glass by subjecting the glass plate with the polarizing film to autoclave treatment at 50 ° C. and 0.5 MPa for 15 minutes. The polarizing film-attached glass plate (hereinafter, also referred to as “initial glass plate”) on which such treatment was performed was maintained at 85 ° C. for 500 hours (heating test). Further, the initial glass plate was subjected to a treatment for 500 hours in an atmosphere of 60 ° C./95% RH (relative humidity) (humidification test). Further, 300 heat cycles were performed in which the initial glass plate was maintained at 85 ° C. for 30 minutes and at −40 ° C. for 30 minutes (heat shock test). After each test, the appearance between the polarizing film and the glass was visually evaluated according to the following criteria. The evaluation results are shown in Tables 7, 8, and 9.

  A: There is no change in appearance such as foaming, peeling, and lifting.

  ：: There is slight peeling or foaming at the end, but there is no practical problem.

  Δ: There is peeling or foaming at the end, but there is no practical problem unless it is a special use.

  X: There is remarkable peeling at the end, and there is a practical problem.

  (2) Evaluation of adhesion and reworkability

  An adhesive strength evaluation test was performed on the adhesive polarizing film (adhesive optical film) according to each of the examples and comparative examples. Specifically, an adhesive-type polarizing film (sample) was cut into a width of 25 mm x a length of 100 mm, and affixed to a 0.5 mm-thick non-alkali glass plate (Eagle XG manufactured by Corning Co., Ltd.) using a laminator. I attached. Next, the polarizing film was completely adhered to the alkali-free glass by autoclaving the glass plate with the polarizing film at 50 ° C. and 5 atm for 15 minutes. Thus, an initial glass plate was manufactured. Next, the initial glass plate was heated under a drying condition of 50 ° C. for 48 hours. Thus, a heated glass plate was manufactured. Then, the adhesion between the initial glass plate and the heated glass plate was measured by the following method.

  That is, the adhesive force (N / 25 mm) when peeling the polarizing film from each glass plate was measured using a tensile tester (Orientec Co., Ltd. product, Tensilon Universal Material Tester STA-1150). The measurement conditions were 23 ° C., a relative humidity of 50%, a peel angle of 180 °, and a peel speed of 300 mm / min. The peeling was performed in accordance with the method of the pressure-sensitive adhesive tape and pressure-sensitive adhesive sheet test of JIS Z0237.

  In addition, a reworkability evaluation test was performed on the adhesive polarizing film (sample). Specifically, first, an initial glass plate and a heated glass plate were manufactured by performing the same treatment as in the adhesive strength evaluation test on the adhesive polarizing film (sample). However, the size of the adhesive polarizing film (sample) was 420 mm in width × 320 mm in length. Thereafter, the polarizing film was peeled off from the initial glass plate and the heated glass plate by hand. Then, the same processing as described above was repeated three times. That is, three initial glass plates and three heated glass plates were prepared, and the polarizing film was peeled off from each glass plate. Then, the reworkability (actual reworkability) of each pressure-sensitive adhesive composition was evaluated based on the following criteria, and the results are shown in Tables 7, 8, and 9.

  A: All of the three sheets can be peeled satisfactorily without glue residue or breakage of the polarizing film. There was no breakage of the alkali-free glass.

  ：: Some of the three films were broken, but peeled off again. There was no breakage of the alkali-free glass.

  Δ: All three films were broken, but were peeled by peeling again. There was no breakage of the alkali-free glass.

  ×: All three sheets could not be peeled off due to the breakage of the film even when the adhesive remained or even when peeled several times. In addition, the alkali-free glass was sometimes broken.

  As shown in Tables 7 and 8, it was confirmed that the pressure-sensitive adhesive composition according to this example had both reworkability and reliability. In particular, the polarizing film and the alkali-free glass used in the evaluation test are all thin, but when the pressure-sensitive adhesive composition according to the present example is used, the polarizing film and the alkali-free glass are hardly destroyed. Could be peeled off. Also, according to Table 9, it can be seen that when the adhesive force exceeds 3 N / 25 mm, the reworkability tends to decrease.

  <B. Example of Reworkability, Reliability and Workability>

  The reworkability, reliability, and workability of the pressure-sensitive adhesive layer (whether aging of the pressure-sensitive adhesive film was required) were evaluated by the following Examples and Comparative Examples.

  Silicate oligomer

  A. As the silicate oligomer, A. The silicate oligomer used in Examples for reworkability and reliability evaluation was prepared. Specifically, the above silicate oligomers B1 (Production Example 10), B2 (Production Example 11), methyl silicate 51 (silicate oligomer B3), methyl silicate 53A (silicate oligomer B4), MKC silicate MS58B15 (silicate oligomer B5), EMS -485 (silicate oligomer B6) and ethyl silicate 48 (silicate oligomer B7) were prepared.

  Peroxide crosslinking agent

  As the peroxide-based crosslinking agent, A.I. In addition to perroyl TCP (1 minute half-life temperature 92.1 ° C.) used in Examples for reworkability and reliability evaluation, perbutyl ND (NOF Corporation, 1 minute half-life temperature 103.5 ° C.) , Perbutyl PV (NOF CORPORATION, 1 minute half-life temperature 110.3 ° C) was prepared.

  Manufacture of optical films

  A. An optical film (one-sided polarizing film) used in Examples for reworkability and reliability evaluation was prepared.

  Examples 23 to 47 and Comparative Examples 9 to 15

  Except that the composition of the pressure-sensitive adhesive composition was the composition of Table 10 and Table 11, and that the drying temperature was applied to the temperature shown in Table 10 and Table 11, the pressure-sensitive adhesive was the same as that in Example 1. A film was produced. Specifically, different drying temperatures were applied depending on the type of the peroxide-based crosslinking agent. For example, Example 23 applied Parloyl TCP with a 1 minute half-life temperature of 92.1 ° C. and a drying temperature of 120 ° C. (2 minutes). By this drying treatment, 50% by weight or more of the peroxide-based crosslinking agent was decomposed.

  In Table 11, V-05 is a carbodiimide-based cross-linking agent manufactured by Nisshinbo Industries, Inc. WS-500 is an oxazoline-based cross-linking agent manufactured by Nippon Shokubai Co., Ltd. It is a system crosslinking agent.

  <Physical property evaluation method>

  (1) Reliability, adhesive strength and reworkability evaluation test: Evaluation was performed in the same manner as in the examples for reworkability and reliability evaluation, and the results are shown in Tables 12 and 13.

  (2) Calculation of gel fraction: The gel fraction was determined by drying the pressure-sensitive adhesive composition at 100 ° C. for 2 minutes so that the thickness after drying became 20 μm, followed by crosslinking treatment to form a pressure-sensitive adhesive layer. After leaving the pressure-sensitive adhesive layer left at a temperature of 23 ° C. and a humidity of 65% RH for 1 hour, it can be calculated by the following equation 1.

  [Equation 1]

  Gel fraction (% by weight) = {(Wc−Wa) / (Wb−Wa)} × 100

  In the above formula 1, Wb is the weight when 0.2 g of the adhesive layer is covered with a fluororesin (TEMISHNTF-1122, Nitto Denko Corporation), and Wa is the weight of the fluororesin. In addition, Wc extracts the soluble component by immersing the adhesive layer covered with the fluororesin in 40 ml of ethyl acetate at 23 ° C. for 7 days, and the adhesive layer covered with the fluororesin at 130 ° C. on an aluminum cup. This is the weight of the pressure-sensitive adhesive layer covered with a fluororesin from which soluble components have been removed after drying for 2 hours.

  (3) Evaluation of necessity of aging (workability): When the gel fraction calculated above is 40% by weight or more, there is no fear of a pressing phenomenon and a decrease in durability, and no aging treatment is required. Therefore, the necessity of aging was evaluated by the gel fraction as follows. The evaluation results are shown in Tables 12 and 13.

  ：: When the gel fraction is 65% or more, there is no possibility of a press phenomenon, a decrease in workability and a decrease in durability.

  Δ: When the gel fraction is 40% or more and less than 65%, there is no fear of a pressing phenomenon.

  X: When the gel fraction is less than 40%, a press phenomenon occurs, and workability and durability deteriorate.

  Here, the press phenomenon refers to A.I. When manufactured like a pressure-sensitive adhesive optical film (sample) for reworkability and reliability evaluation, it means that a press is confirmed with the naked eye on the surface of the optical film. Manufacture (420 mm × 320 mm) like an adhesive optical film (sample) for evaluation of reworkability and reliability, make a square hole with a side length of 270 mm in the optical film within 1 hour, Means that the adhesiveness is felt on the side surface of the polarizing film with the touch and the naked eye, and the presence or absence of surface contamination of the polarizing film is observed.

  (4) Measurement of PET oligomer deposition amount: After the adhesive polarizing film (including the separator) produced as described above was allowed to stand at 60 ° C. and 90% RH for 500 hours, the separator was removed. Subsequently, 0.025 g of the pressure-sensitive adhesive layer was collected with a pressure-sensitive adhesive-type polarizing film, 1 ml of chloroform was added, and the mixture was shaken at room temperature for 18 hours, and then 5 ml of acetonitrile was further extracted and shaken for 3 hours. The obtained solution was filtered through a 0.45 ml membrane filter, and a standard curve of a trimer PET oligomer was adjusted to a constant concentration to prepare a calibration curve, which was included in the adhesive using the calibration curve. The amount (ppm) of PET oligomer was required. The calibration curve was measured by HPLC (High Performance Liquid Chromatography) using a sample for which the concentration (ppm) of the PET oligomer was known. The HPLC apparatus, HPLC measurement conditions, and the method of quantifying the amount of PET oligomer are as follows.

  HPLC system: Agilent Technologies 1200 series

  Measurement condition

  Column: Agilent Technologies ZORBAX SB-C18

  Column temperature: 40 ° C

  Heat flow rate: 0.8ml / min

  Eluent composition: water / acetonitrile reverse phase gradient conditions

  Injection volume: 5 μl

  Detector: PDA (photodiode array)

  Quantitative method: After a standard sample of the PET oligomer trimer was dissolved in chloroform, the sample was adjusted to a constant concentration by diluting it with acetonitrile. A calibration curve was created based on the HPLC area and the adjusted concentration. Then, the amount of the sample PET oligomer (the amount of the oligomer deposited on the pressure-sensitive adhesive layer) was determined according to the calibration curve. The results are shown in Tables 12 and 13.

  As shown in Tables 12 and 13, the pressure-sensitive adhesive compositions according to the examples include pressure-sensitive adhesive resins (A) having an acid value of 0 mgKOH / g to 20.0 mgKOH / g, which are base polymers, and silicate oligomers (B). ) And a peroxide-based crosslinking agent. The pressure-sensitive adhesive optical film having a pressure-sensitive adhesive layer obtained from such a pressure-sensitive adhesive composition has the pressure-sensitive adhesive layer attached to a liquid crystal cell or the like by containing the silicate oligomer (B). Immediate adhesion can be reduced. In addition, even if a long time elapses due to various processes or storage at a high temperature, there is no increase in adhesive force to a liquid crystal cell or the like, and the adhesive optical film can be easily peeled from the liquid crystal cell or the like. It is possible and has excellent reworkability. That is, the adhesive optical film can be reused without damaging or contaminating the liquid crystal cell. In particular, it was difficult to peel off the flat adhesive optical film in a large liquid crystal cell, but according to the present invention, the flat adhesive optical film can be easily peeled even in a large liquid crystal cell.

  In this example, the peroxide-based crosslinking agent is contained in the pressure-sensitive adhesive composition solution at a specific ratio, and when heating and drying the coating film of the pressure-sensitive adhesive composition solution, aging is not required. The present invention provides a pressure-sensitive adhesive optical film having excellent reworkability and reliability, and excellent handling properties in the production process. Further, by setting the drying temperature to 130 ° C. or lower, the amount of oligomers deposited on the pressure-sensitive adhesive layer can be reduced.

  Although the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, the present invention is not limited to such examples. It is clear that any person having ordinary knowledge in the technical field to which the present invention pertains can conceive various variations or modifications within the scope of the technical idea described in the claims. It is understood that these also belong to the technical scope of the present invention.

Claims (19)

An adhesive resin having an acid value of 0 mgKOH / g to 20.0 mgKOH / g;
A silicate oligomer represented by the following Chemical Formula 1; and a crosslinking agent;
A pressure-sensitive adhesive composition for an optical film comprising:
The adhesive resin includes one or more of a (meth) acrylic polymer, a urethane polymer, and a polyester,
The (meth) acrylic polymer has a weight average molecular weight of 300,000 to 3,000,000,
The urethane polymer and the polyester have a weight average molecular weight of 10,000 to 200,000 and an acid value of more than 0 mgKOH / g and 10.0 mgKOH / g or less,
In the pressure-sensitive adhesive layer formed of the pressure-sensitive adhesive composition for an optical film, the difference between the initial adhesive force and the adhesive force after heating is 1 N / 25 mm or less. Pressure-sensitive adhesive composition for an optical film, which is an adhesive force after heating for 48 hours at:
In the Chemical Formula 1, R _{1 to} R ₄ are each independently hydrogen, an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and X ₁ and X ₂ are each independently Hydrogen, an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and n is an integer of 1 to 100.   The pressure-sensitive adhesive composition for an optical film according to claim 1, wherein the pressure-sensitive adhesive resin includes a hydroxyl group-containing monomer as a constituent unit.   The pressure-sensitive adhesive composition for an optical film according to claim 1, wherein the pressure-sensitive adhesive resin has a glass transition temperature (Tg) of -100C to -10C.   The pressure-sensitive adhesive composition for an optical film according to claim 1, wherein the weight average molecular weight of the silicate oligomer is 300 to 30,000. The silicate oligomer may be a silicate oligomer in which R _{1 to} R ₄ , X ₁ and X ₂ are methyl groups in Formula 1 and have a weight average molecular weight of 300 to 20,000. In Formula 1, R _{1 to} R ₄ , A silicate oligomer having a weight average molecular weight of more than 20,000 and 30,000 or less, wherein X ₁ and X ₂ are methyl groups, and R ₁ , R ₂ , R ₃ , R ₄ , X ₁ or X _{2. The} pressure-sensitive adhesive composition for an optical film according to claim 1, wherein 2 comprises at least one of silicate oligomers containing a phenyl group. 3.   The pressure-sensitive adhesive composition for an optical film according to claim 1, wherein the pressure-sensitive adhesive composition comprises 0.01 to 50 parts by weight of the silicate oligomer based on 100 parts by weight of the pressure-sensitive adhesive resin.   The pressure-sensitive adhesive composition may include, as the cross-linking agent, one or more of an isocyanate-based cross-linking agent, a carbodiimide-based cross-linking agent, an oxazoline-based cross-linking agent, an epoxy-based cross-linking agent, and a peroxide-based cross-linking agent. The pressure-sensitive adhesive composition for an optical film according to claim 1, wherein the pressure-sensitive adhesive composition comprises 0.01 to 20 parts by weight based on 100 parts by weight.   The pressure-sensitive adhesive composition for an optical film according to claim 1, wherein the pressure-sensitive adhesive composition contains 0.02 parts by weight to 2 parts by weight of a peroxide-based crosslinking agent with respect to 100 parts by weight of the pressure-sensitive adhesive resin.   The pressure-sensitive adhesive composition for an optical film according to claim 1, wherein the pressure-sensitive adhesive composition further includes 0.001 to 10 parts by weight of a silane coupling agent based on 100 parts by weight of the pressure-sensitive adhesive resin.   An adhesive layer formed of the adhesive composition for an optical film according to claim 1. An adhesive resin containing at least one of a (meth) acrylic polymer, a urethane polymer and a polyester;
A silicate oligomer represented by the following Chemical Formula 1; and a peroxide-based crosslinking agent;
An adhesive layer formed by a crosslinking treatment of an adhesive composition comprising:
The (meth) acrylic polymer has a weight average molecular weight of 300,000 to 3,000,000, and an acid value of 0 mgKOH / g to 20.0 mgKOH / g,
The urethane polymer and the polyester have a weight average molecular weight of 10,000 to 200,000 and an acid value of more than 0 mgKOH / g and 10.0 mgKOH / g or less,
After the adhesive layer is formed and left for 1 hour at a temperature of 23 ° C. and a humidity of 65% RH, the gel fraction according to the following formula 1 is 40% by weight to 95% by weight,
The adhesive layer has a difference between the initial adhesive strength and the adhesive strength after heating of 1 N / 25 mm or less, and the adhesive strength after heating is the adhesive strength after heating the adhesive layer at 50 ° C. for 48 hours. , Adhesive layer:
In the chemical formula 1, R _{1 to} R ₄ are each independently hydrogen, an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and X ₁ and X ₂ are each independently Hydrogen, an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, n is an integer of 1 to 100,
[Equation 1]
Gel fraction (% by weight) = {(Wc−Wa) / (Wb−Wa)} × 100
In the above formula 1, Wb is the weight when 0.2 g of the adhesive layer is covered with a fluororesin (TEMISHNTF-1122, Nitto Denko Corporation), and Wa is the weight of the fluororesin. Further, Wc extracts the soluble component by immersing the adhesive layer covered with the fluororesin in 40 ml of ethyl acetate at 23 ° C. for 7 days, and the adhesive layer covered with the fluororesin at 130 ° C. on an aluminum cup. This is the weight of the pressure-sensitive adhesive layer covered with a fluororesin from which soluble components have been removed after drying for 2 hours. The adhesive layer is temperature 23 ° C., allowed to stand for 1 hour under a condition of RH 65% humidity is 65% to 95% by weight gel fraction according to formula 1 below, according to claim 1 0 or 1 1 Adhesive layer:
[Equation 1]
Gel fraction (% by weight) = {(Wc−Wa) / (Wb−Wa)} × 100
In the above formula 1, Wb is the weight when 0.2 g of the adhesive layer is covered with a fluororesin (TEMISHNTF-1122, Nitto Denko Corporation), and Wa is the weight of the fluororesin. Further, Wc extracts the soluble component by immersing the adhesive layer covered with the fluororesin in 40 ml of ethyl acetate at 23 ° C. for 7 days, and the adhesive layer covered with the fluororesin at 130 ° C. on an aluminum cup. This is the weight of the pressure-sensitive adhesive layer covered with a fluororesin from which soluble components have been removed after drying for 2 hours. The adhesive layer, the adhesive strength after heating is less than 3N / 25 mm, the adhesive layer according to claim 1 0 or 1 1. The thickness of the adhesive layer is 2Myuemu～40myuemu, adhesive layer according to claim 1 0 or 1 1. Polarizer;
A protective layer formed on one surface of the polarizer;
An adhesive layer formed on the other surface of the polarizer;
Including
The adhesive layer is pressure-sensitive adhesive optical film, which is one of the adhesive layer any of claims 1 0 and 1 1. The pressure-sensitive adhesive optical film according to claim 15 , wherein an adhesion auxiliary layer is formed between the polarizer and the pressure-sensitive adhesive layer. The adhesion auxiliary layer is formed on one or more of the surface of the polarizer and the surface of the adhesive layer,
17. The pressure-sensitive adhesive optical film according to claim 16 , wherein the adhesion auxiliary layer is formed by corona treatment. The pressure-sensitive adhesive optical film according to claim 15 , wherein the protective layer is a transparent protective film or a protective coating layer. A display device comprising the pressure-sensitive adhesive optical film according to any one of claims 15 to 18 .