JP5500780B2 - Adhesive polarizing plate, image display device, and manufacturing method thereof - Google Patents

Description

  The present invention relates to an adhesive polarizing plate in which a transparent protective film is provided only on one side of a polarizer and an adhesive layer is laminated on the other side. Furthermore, the present invention relates to an image display device using the adhesive polarizing plate. Furthermore, the present invention relates to a method for manufacturing the image display device.

  In the liquid crystal display device, it is indispensable to dispose polarizing plates on both sides of the glass substrate on which the liquid crystal panel surface is formed because of the image forming method. In general, a polarizing plate is made of a polyvinyl alcohol-based film and a transparent protective film for a polarizer using triacetyl cellulose or the like on one or both sides of a polarizer made of a dichroic material such as iodine. What was bonded together with the agent is used.

  When adhering the polarizing plate to a liquid crystal cell or the like, an adhesive is usually used. In addition, the adhesive is provided as an adhesive layer in advance on one side of the polarizing plate because it has the merits of being able to fix the polarizing plate instantly and not requiring a drying step to fix the polarizing plate. . That is, an adhesive polarizing plate is generally used for attaching the polarizing plate.

  Necessary characteristics required for the pressure-sensitive adhesive layer include that the polarizing plate is attached to the liquid crystal panel when the polarizing plate is bonded to the liquid crystal cell in the case where the bonding position is wrong or foreign matter is caught in the bonding surface. It is required that it can be peeled off from the surface and pasted (reworked) again. Various types of pressure-sensitive adhesive layers that improve the reworkability have been proposed (Patent Document 1). In addition, it has been proposed to use a curable adhesive in order to improve moisture resistance and the like when bonding a polarizer and a protective film (or a liquid crystal cell) (Patent Documents 2 and 3).

JP 2004-20896 A Japanese Utility Model Publication No.2-271121 JP 2005-309401 A

  The pressure-sensitive adhesive layer for improving the reworkability according to Patent Document 1 is usually applied to a polarizing plate provided with a transparent protective film on both sides of a polarizer, and the polarizing plate is applied to the polarizing plate during rework. Breakage does not occur and workability of rework does not deteriorate. On the other hand, from the viewpoint of thinning, a polarizing plate provided with a transparent protective film only on one side of the polarizer is used. However, the polarizing plate is weaker than a polarizing plate provided with a transparent protective film on both sides, and is reworked. In this case, the polarizing plate is easily broken and the workability of the rework is lowered. On the other hand, if the adhesive force of the pressure-sensitive adhesive layer is reduced in order to improve the workability of rework, floating or the like occurs between the pressure-sensitive adhesive layer and the adherend, and the pressure-sensitive adhesive layer is originally applied to the polarizing plate. It is difficult to ensure the performance. Moreover, the curable adhesive which concerns on patent document 1 is described only from a moisture-resistant viewpoint, and does not satisfy the peelability which concerns on rework.

  The present invention is an adhesive polarizing plate having a transparent protective film only on one side of the polarizer and an adhesive layer on the other side, satisfying the adhesive properties as an adhesive polarizing plate, and breaking An object of the present invention is to provide a pressure-sensitive adhesive polarizing plate that can be easily reworked without causing any problems.

  Another object of the present invention is to provide an image display device having the pressure-sensitive adhesive polarizing plate and a method for producing the same.

  As a result of intensive studies, the inventors of the present application have found that the above-mentioned problems can be solved by the following pressure-sensitive adhesive polarizing plate, and have reached the present invention.

  That is, in the present invention, the transparent protective film (E) is provided only on one side of the polarizer (P) through the adhesive layer (G), and the other side of the polarizer (P) is curable. The present invention relates to a pressure-sensitive adhesive polarizing plate provided with a pressure-sensitive adhesive layer (B).

  In the pressure-sensitive adhesive polarizing plate, the curable pressure-sensitive adhesive layer (B) can be formed of a pressure-sensitive adhesive composition containing 20 to 200 parts by weight of a radiation-curable component with respect to 100 parts by weight of the pressure-sensitive adhesive polymer. The pressure-sensitive adhesive composition can be further contained in an amount of 20 parts by weight or less of the radiation-cleavable polymerization initiator with respect to 100 parts by weight of the pressure-sensitive polymer.

    In the pressure-sensitive adhesive polarizing plate, the curable pressure-sensitive adhesive layer (B) is 20 to 200 parts by weight of a thermosetting component and 0.05 to 20 parts by weight of a heat-cleavable polymerization initiator with respect to 100 parts by weight of the pressure-sensitive adhesive polymer. It can form with the adhesive composition containing this.

  In the pressure-sensitive adhesive polarizing plate, the pressure-sensitive adhesive composition preferably further contains 0.01 to 30 parts by weight of a crosslinking agent with respect to 100 parts by weight of the pressure-sensitive adhesive polymer.

  In the adhesive polarizing plate, the adhesive polymer is preferably an acrylic polymer or a polyester polymer.

  In the pressure-sensitive adhesive polarizing plate, the curable pressure-sensitive adhesive layer (B) preferably has a pressure-sensitive adhesive force to glass after curing of 2 N / 25 mm or less.

  The present invention also relates to an image display device having the pressure-sensitive adhesive polarizing plate.

  Further, the present invention is a method for manufacturing the image display device, a roll raw fabric preparation step of preparing a long sheet of the pressure-sensitive adhesive polarizing plate as a roll raw fabric, a sheet product is fed out from the roll raw fabric, and cut A cutting step of cutting the pressure-sensitive adhesive polarizing plate into a predetermined size using means, and a bonding step of bonding to the optical display unit via the curable pressure-sensitive adhesive layer (B) of the pressure-sensitive adhesive polarizing plate after the cutting step And a method of manufacturing an image display device having

  The pressure-sensitive adhesive polarizing plate of the present invention has a transparent protective film (E) only on one side of the polarizer (P), but a curable pressure-sensitive adhesive layer (B) is provided on the other side of the polarizer (P). Have. The curable pressure-sensitive adhesive layer (B) can be designed so as to satisfy the pressure-sensitive adhesive properties, and when reworking, the curable pressure-sensitive adhesive layer (B) is irradiated or heated. The adhesive strength of the curable pressure-sensitive adhesive layer (B) can be easily reduced by curing the curable pressure-sensitive adhesive layer (B). Therefore, the pressure-sensitive adhesive polarizing plate of the present invention uses a thin polarizing plate in which the transparent protective film (E) is provided only on one side of the polarizer (P). Rework can be easily performed without causing any problems.

  In addition, since the pressure-sensitive adhesive polarizing plate of the present invention can be easily reworked, work efficiency is high when manufacturing an image display device using the pressure-sensitive adhesive polarizing plate. In particular, it is suitable in the manufacturing method of the image display apparatus which performs from the roll original fabric preparation process of an adhesion type polarizing plate to a cutting process and the bonding process bonded together to an optical display unit as a series of processes.

  Hereinafter, the pressure-sensitive adhesive polarizing plate of the present invention will be described with reference to FIG. In the pressure-sensitive adhesive polarizing plate of the present invention, for example, as shown in FIG. 1, a transparent protective film (E) is provided only on one side of a polarizer (P) via an adhesive layer (G). On the other side of the child (P), a curable pressure-sensitive adhesive layer (B) is provided. Although not shown, the pressure-sensitive adhesive polarizing plate of the present invention has an adhesive layer (G) bonded thereto by providing an easy-adhesion layer or applying an activation treatment to the transparent protective film (E). Can do. Moreover, an easily bonding layer can also be provided between a polarizer (P) and a curable adhesive layer (B). Although not shown, a release sheet can be provided in the thermosetting pressure-sensitive adhesive layer (B).

[Polarizer]
A polarizer refers to a film that can be converted from natural light or polarized light into arbitrary polarized light. Any appropriate polarizer may be adopted as the polarizer used in the present invention, but a polarizer that converts natural light or polarized light into linearly polarized light is preferably used.

  In the polarizing plate of this invention, arbitrary appropriate things can be employ | adopted as a polarizer (P) according to the objective. For example, dichroic substances such as iodine and dichroic dyes are adsorbed on hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and ethylene / vinyl acetate copolymer partially saponified films. And a polyene-based oriented film such as a uniaxially stretched product, a polyvinyl alcohol dehydrated product or a polyvinyl chloride dehydrochlorinated product. Further, a guest / host type O-type polarizer in which a liquid crystalline composition containing a dichroic substance and a liquid crystalline compound disclosed in US Pat. No. 5,523,863 is aligned in a certain direction, US Pat. An E-type polarizer or the like in which lyotropic liquid crystals disclosed in US Pat. No. 6,049,428 are aligned in a certain direction can also be used.

  Among such polarizers, from the viewpoint of having a high degree of polarization, a polarizer made of a polyvinyl alcohol film containing iodine is preferably used. Polyvinyl alcohol or a derivative thereof is used as a material for the polyvinyl alcohol film applied to the polarizer. Derivatives of polyvinyl alcohol include polyvinyl formal, polyvinyl acetal, and the like, olefins such as ethylene and propylene, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid, and their alkyl esters and acrylamide. Things. Polyvinyl alcohol having a polymerization degree of about 1000 to 10000 and a saponification degree of about 80 to 100 mol% is generally used.

  The polarizer can also contain zinc. Inclusion of zinc in the polarizer is preferable in terms of suppressing hue deterioration under a heating environment. The zinc content in the polarizer is preferably adjusted so that the zinc element is contained in the polarizer in an amount of 0.002 to 2% by weight. Furthermore, it is preferable to adjust to 0.01 to 1 weight%. When the zinc content in the polarizer is within the above range, the durability improving effect is good, which is preferable for suppressing the deterioration of the hue.

  A zinc salt solution is used for the zinc impregnation treatment. As the zinc salt, an inorganic salt compound of an aqueous solution such as zinc halides such as zinc chloride and zinc iodide, zinc sulfate, and zinc acetate is preferable. Among these, zinc sulfate is preferable because the retention rate of zinc in the polarizer can be increased. Various zinc complex compounds can be used for the zinc impregnation treatment. The concentration of zinc ions in the zinc salt aqueous solution is about 0.1 to 10% by weight, preferably 0.3 to 7% by weight. The zinc salt solution is preferably an aqueous solution containing potassium ions and iodine ions with potassium iodide or the like because zinc ions are easily impregnated. The potassium iodide concentration in the zinc salt solution is preferably about 0.5 to 10% by weight, more preferably 1 to 8% by weight.

  Arbitrary appropriate thickness may be employ | adopted as thickness of the polarizer (P) used for the polarizing plate of this invention. The thickness of the polarizer is typically 5 to 80 μm, preferably 10 to 50 μm, and more preferably 20 to 40 μm. If it is said range, it is excellent in an optical characteristic and mechanical strength.

[Transparent protective film]
As a material constituting the transparent protective film, for example, a thermoplastic resin excellent in transparency, mechanical strength, thermal 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, polyethersulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth) acrylic resins, cyclic Examples thereof include polyolefin resins (norbornene resins), polyarylate resins, polystyrene resins, polyvinyl alcohol resins, and mixtures thereof.

  In addition, 1 or more types of arbitrary appropriate additives may be contained in the transparent protective film. 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 preferably 50 to 100% by weight, more preferably 50 to 99% by weight, still more preferably 60 to 98% by weight, and particularly preferably 70 to 97% by weight. . When content of the said thermoplastic resin in a transparent protective film is 50 weight% or less, there exists a possibility that the high transparency etc. which a thermoplastic resin originally has cannot fully be expressed.

  Although the thickness of a transparent protective film can be determined suitably, generally it is about 1-500 micrometers from points, such as workability | operativity, such as intensity | strength and handleability, and thin layer property. 1-300 micrometers is especially preferable, 5-200 micrometers is more preferable, Furthermore, 5-150 micrometers, especially 20-100 micrometers is especially suitable in the case of a thin type.

  As the transparent protective film of the present invention, it is preferable to use at least one selected from cellulose resin, polycarbonate resin, cyclic polyolefin resin, and (meth) acrylic resin. Among these, in particular, the cellulose resin is used as a transparent protective film, but has a low strength, and thus is suitably used in the present invention.

  Cellulose resin is an ester of cellulose and fatty acid. Specific examples of the cellulose ester resin include triacetyl cellulose, diacetyl cellulose, tripropionyl cellulose, dipropionyl cellulose and the like. Among these, triacetyl cellulose is particularly preferable. Many products of triacetylcellulose are commercially available, which is advantageous in terms of availability and cost. Examples of commercially available products of triacetyl cellulose include trade names “UV-50”, “UV-80”, “SH-80”, “TD-80U”, “TD-TAC”, and “UZ” manufactured by Fujifilm Corporation. -TAC "and" KC series "manufactured by Konica. In general, these triacetyl celluloses have an in-plane retardation (Re) of almost zero, but a thickness direction retardation (Rth) of about 60 nm.

  In addition, the cellulose resin film with a small thickness direction phase difference is obtained by processing the said cellulose resin, for example. For example, a base film such as polyethylene terephthalate, polypropylene, and stainless steel coated with a solvent such as cyclopentanone and methyl ethyl ketone is bonded to a general cellulose film and dried by heating (for example, at 80 to 150 ° C. for about 3 to 10 minutes). ) And then peeling the base film; a solution obtained by dissolving norbornene resin, (meth) acrylic resin, etc. in a solvent such as cyclopentanone, methyl ethyl ketone, etc. is applied to a general cellulose resin film and dried by heating ( For example, a method of peeling the coated film after 80 to 150 ° C. for about 3 to 10 minutes is mentioned.

  Moreover, as a cellulose resin film with a small thickness direction retardation, the fatty acid cellulose resin film which controlled the fat substitution degree can be used. Generally used triacetyl cellulose has an acetic acid substitution degree of about 2.8. Preferably, the Rth can be reduced by controlling the acetic acid substitution degree to 1.8 to 2.7. Rth can be controlled to be small by adding a plasticizer such as dibutyl phthalate, p-toluenesulfonanilide, acetyltriethyl citrate to the fatty acid-substituted cellulose resin. The addition amount of the plasticizer is preferably 40 parts by weight or less, more preferably 1 to 20 parts by weight, and still more preferably 1 to 15 parts by weight with respect to 100 parts by weight of the fatty acid cellulose resin.

  Specific examples of the cyclic polyolefin resin are preferably norbornene resins. The cyclic olefin-based resin is a general term for resins that are polymerized using a cyclic olefin as a polymerization unit, and is described in, for example, JP-A-1-240517, JP-A-3-14882, JP-A-3-122137, and the like. Resin. Specific examples include ring-opening (co) polymers of cyclic olefins, addition polymers of cyclic olefins, cyclic olefins and α-olefins such as ethylene and propylene (typically random copolymers), And graft polymers obtained by modifying them with an unsaturated carboxylic acid or a derivative thereof, and hydrides thereof. Specific examples of the cyclic olefin include norbornene monomers.

  Various products are commercially available as the cyclic polyolefin resin. As specific examples, trade names “ZEONEX” and “ZEONOR” manufactured by ZEON CORPORATION, product names “ARTON” manufactured by JSR Corporation, “TOPAS” manufactured by TICONA, and product names manufactured by Mitsui Chemicals, Inc. “APEL”.

  The (meth) acrylic resin preferably has a Tg (glass transition temperature) of 115 ° C. or higher, more preferably 120 ° C. or higher, still more preferably 125 ° C. or higher, and particularly preferably 130 ° C. or higher. When Tg is 115 ° C. or higher, the polarizing plate can be excellent in durability. Although the upper limit of Tg of the (meth) acrylic resin is not particularly limited, it is preferably 170 ° C. or lower from the viewpoint of moldability and the like. From the (meth) acrylic resin, a film having in-plane retardation (Re) and thickness direction retardation (Rth) of almost zero can be obtained.

  As the (meth) acrylic resin, any appropriate (meth) acrylic resin can be adopted as long as the effects of the present invention are not impaired. For example, poly (meth) acrylic acid ester such as polymethyl methacrylate, methyl methacrylate- (meth) acrylic acid copolymer, methyl methacrylate- (meth) acrylic acid ester copolymer, methyl methacrylate-acrylic acid ester- (Meth) acrylic acid copolymer, (meth) methyl acrylate-styrene copolymer (MS resin, etc.), polymer having an alicyclic hydrocarbon group (for example, methyl methacrylate-cyclohexyl methacrylate copolymer, Methyl methacrylate- (meth) acrylate norbornyl copolymer, etc.). Preferably, poly (meth) acrylate C1-6 alkyl such as poly (meth) acrylate methyl is used. More preferred is a methyl methacrylate resin containing methyl methacrylate as a main component (50 to 100% by weight, preferably 70 to 100% by weight).

  Specific examples of (meth) acrylic resins include (meth) acrylic resins having a ring structure in the molecule described in, for example, Acrypet VH and Acrypet VRL20A manufactured by Mitsubishi Rayon Co., Ltd., and JP-A-2004-70296. And a high Tg (meth) acrylic resin system obtained by intramolecular crosslinking or intramolecular cyclization reaction.

  As the (meth) acrylic resin, a (meth) acrylic resin having a lactone ring structure can also be used. Examples of the (meth) acrylic resin having a lactone ring structure include JP 2000-230016, JP 2001-151814, JP 2002-120326, JP 2002-254544, and JP 2005. No. 146084 and the like.

  As the (meth) acrylic resin, an acrylic resin having a structural unit of unsaturated carboxylic acid alkyl ester and a structural unit of glutaric anhydride can be used. Examples of the acrylic resin include Japanese Patent Application Laid-Open Nos. 2004-70290, 2004-70296, 2004-163924, 2004-292812, 2005-314534, and 2006. No. 131898, JP 2006-206881 A, JP 2006-265532 A, JP 2006-283013 A, JP 2006-299005 A, JP 2006-335902 A, and the like. It is done.

  In addition, as the (meth) acrylic resin, a thermoplastic resin having a glutarimide unit, a (meth) acrylic ester unit, and an aromatic vinyl unit can be used. Examples of the thermoplastic resin include JP 2006-309033 A, JP 2006-317560 A, JP 2006-328329 A, JP 2006-328334 A, JP 2006-337491 A, and JP 2006. -337492, JP-A-2006-337493, JP-A-2006-337569, and the like.

(Phase difference value of transparent protective film)
As the transparent protective film (E), a film having a small front refraction of less than 40 nm and a thickness direction retardation of less than 80 nm can be used as having a small birefringence and not converting the polarization state. Thus, an unstretched film is used suitably as a transparent protective film with small birefringence.

  The front phase difference Re is represented by Re = (nx−ny) × d. The thickness direction retardation Rth is represented by Rth = (nx−nz) × d. The Nz coefficient is represented by Nz = (nx−nz) / (nx−ny). [However, the refractive indexes in the slow axis direction, the fast axis direction, and the thickness direction of the film are nx, ny, and nz, respectively, and d (nm) is the thickness of the film. The slow axis direction is the direction that maximizes the refractive index in the film plane. ].

  In addition, an optically compensated phase difference plate in which an alignment layer of a liquid crystal polymer, particularly an optically anisotropic layer composed of a tilted alignment layer of a discotic liquid crystal polymer, is supported by a triacetyl cellulose film in order to achieve a wide viewing angle with good visibility. Etc. can also be used.

[Adhesive layer]
The transparent protective film (E) and the polarizer (P) are laminated via the adhesive layer (G). At this time, it is desirable to laminate both of them with an adhesive layer without an air gap. The adhesive layer (G) is formed of an adhesive. The type of the adhesive is not particularly limited, and various types can be used.

  The adhesive layer used for laminating the polarizer and the transparent protective film is not particularly limited as long as it is optically transparent, and water-based, solvent-based, hot-melt-based, and radical-curing types are used. A water-based adhesive or a radical curable adhesive is suitable.

[Curable adhesive layer]
The curable pressure-sensitive adhesive layer (B) can be formed by, for example, a pressure-sensitive adhesive composition containing a pressure-sensitive polymer, radiation, or a thermosetting component. In the case where the pressure-sensitive adhesive composition contains a radiation curable component, when an electron beam or the like is used for radiation, the pressure-sensitive adhesive composition does not need to contain a radiation-cleavable polymerization initiator, When ultraviolet rays are used for radiation, a radiation-cleavable polymerization initiator is contained. On the other hand, when the pressure-sensitive adhesive composition contains a thermosetting component, the pressure-sensitive adhesive composition contains a heat-cleavable polymerization initiator.

  The adhesive strength of the curable pressure-sensitive adhesive layer (B) to the glass is preferably about 10 N / 25 mm before curing, and preferably 2 N / 25 mm or less after curing. If the adhesive strength after curing is greater than 2 N / 25 mm, it will take too much time to peel off during rework, and if the glass substrate of the liquid crystal cell as the adherend is several μm, the glass substrate may be damaged. There is.

<Adhesive polymer>
The adhesive polymer is not particularly limited as long as it is an adhesive polymer that is generally used as a base polymer of an adhesive, but Tg is −20 ° C. or lower (usually −100 ° C.) because the adhesive performance is easily balanced. C. or higher) is preferred. Among such adhesive polymers, acrylic polymers, polyester polymers, and the like are preferably used in consideration of compatibility with radiation curable components.

  The acrylic polymer has a monomer unit of (meth) acrylic acid alkyl ester as a main skeleton. The (meth) acrylic acid alkyl ester refers to an acrylic acid alkyl ester and / or a methacrylic acid alkyl ester, and (meth) in the present invention has the same meaning. Examples of the (meth) acrylic acid alkyl ester constituting the main skeleton of the acrylic polymer include linear or branched alkyl groups having 1 to 20 carbon atoms. For example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, (meth) acrylic Illustrative examples include isononyl acid, isomyristyl (meth) acrylate, and lauryl (meth) acrylate. These can be used alone or in combination. The average carbon number of these alkyl groups is preferably 3-9.

  In the acrylic polymer, one or more kinds of copolymerization monomers can be introduced by copolymerization for the purpose of improving adhesiveness and heat resistance. Specific examples of such copolymerization monomers include, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, (meth) acrylic acid 6 Hydroxyl group-containing monomers such as hydroxyhexyl, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate and (4-hydroxymethylcyclohexyl) -methyl acrylate Carboxyl group-containing monomers such as (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid and crotonic acid; acid anhydrides such as maleic anhydride and itaconic anhydride Monomer-containing monomer; Caprolac of acrylic acid Adducts such as styrene sulfonic acid, allyl sulfonic acid, 2- (meth) acrylamide-2-methylpropane sulfonic acid, (meth) acrylamide propane sulfonic acid, sulfopropyl (meth) acrylate, (meth) acryloyloxynaphthalene sulfonic acid, etc. And sulfonic acid group-containing monomers such as 2-hydroxyethyl acryloyl phosphate.

  Moreover, (meth) acrylamide, N-hydroxy (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-butyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methylolpropane (meth) acrylamide, etc. (N-substituted) amide monomers: (meth) acrylic acid aminoethyl, (meth) acrylic acid N, N-dimethylaminoethyl, (meth) acrylic acid t-butylaminoethyl (meth) acrylic acid alkylamino Alkyl monomers; (meth) acrylic acid alkoxyalkyl monomers such as methoxyethyl (meth) acrylate and ethoxyethyl (meth) acrylate; N- (meth) acryloyloxymethylene succinimide and N- (meth) acryloyl-6 Oxyhexamethylenesk Succinimide monomers such as N-imide, N- (meth) acryloyl-8-oxyoctamethylenesuccinimide, N-acryloylmorpholine; maleimide monomers such as N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide and N-phenylmaleimide Itaconimide monomers such as N-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N-octylitaconimide, N-2-ethylhexitaconimide, N-cyclohexylitaconimide, N-laurylitaconimide, These are also examples of monomers for modification purposes.

  Further, as modifying monomers, vinyl acetate, vinyl propionate, N-vinyl pyrrolidone, methyl vinyl pyrrolidone, vinyl pyridine, vinyl piperidone, vinyl pyrimidine, vinyl piperazine, vinyl pyrazine, vinyl pyrrole, vinyl imidazole, vinyl oxazole, vinyl morpholine, N- Vinyl monomers such as vinylcarboxylic acid amides, styrene, α-methylstyrene, N-vinylcaprolactam; cyanoacrylate monomers such as acrylonitrile and methacrylonitrile; epoxy group-containing acrylic monomers such as glycidyl (meth) acrylate; (Meth) acrylic acid polyethylene glycol, (meth) acrylic acid polypropylene glycol, (meth) acrylic acid methoxyethylene glycol, (meth) acrylic acid meth Glycol acrylic ester monomers such as polypropylene glycol; acrylic acid ester monomers such as tetrahydrofurfuryl (meth) acrylate, fluorine (meth) acrylate, silicone (meth) acrylate and 2-methoxyethyl acrylate may also be used. it can.

  The acrylic polymer has (meth) acrylic acid alkyl ester as a main component in the weight ratio of all constituent monomers, and the ratio of the copolymer monomer in the acrylic polymer is not particularly limited, but the ratio of the copolymer monomer is The weight ratio of all constituent monomers is preferably about 0 to 30%, about 0.1 to 25%, and more preferably about 0.5 to 20%.

  Among these copolymer monomers, a hydroxyl group-containing monomer and a carboxyl group-containing monomer are preferably used from the viewpoint of adhesiveness and durability. These monomers serve as reaction points with the crosslinking agent. Since a hydroxyl group-containing monomer, a carboxyl group-containing monomer, and the like are rich in reactivity with an intermolecular crosslinking agent, they are preferably used for improving the cohesiveness and heat resistance of the resulting pressure-sensitive adhesive layer.

  The average molecular weight of the acrylic polymer is not particularly limited, but the weight average molecular weight is preferably about 300,000 to 2.5 million. The acrylic polymer can be produced by various known methods. For example, a radical polymerization method such as a bulk polymerization method, a solution polymerization method, or a suspension polymerization method can be appropriately selected. As the radical polymerization initiator, various known azo and peroxide initiators can be used. The reaction temperature is usually about 50 to 80 ° C., and the reaction time is 1 to 8 hours. Among the above production methods, the solution polymerization method is preferable, and ethyl acetate, toluene and the like are generally used as the solvent for the acrylic polymer. The solution concentration is usually about 20 to 80% by weight.

  As the polyester polymer, a saturated polyester or copolyester of a polyhydric alcohol and a polycarboxylic acid is usually used.

  Examples of the polyhydric alcohol include ethylene glycol, propylene glycol, hexamethylene glycol, neopentyl glycol, 1,2-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, decamethylene glycol, 1,3-propanediol, , 4-butanediol, 1,5-pentanediol, 1,6-hexadiol, 2,2-bis (4-hydroxyphenyl) propane, bis (4-hydroxyphenyl) sulfone and the like.

  Examples of the polyvalent carboxylic acid include terephthalic acid, isophthalic acid, orthophthalic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, Aromatic dicarboxylic acids such as diphenylcarboxylic acid, diphenoxyethanedicarboxylic acid, diphenylsulfonecarboxylic acid, anthracenedicarboxylic acid; 1,3-cyclopentanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, Alicyclic dicarboxylic acids such as hexahydroterephthalic acid and hexahydroisophthalic acid; malonic acid, dimethylmalonic acid, succinic acid, 3,3-diethylsuccinic acid, glutaric acid, 2,2-dimethylglutaric acid, adipic acid, 2 -Methyl adipic acid, trimethyl Adipic acid, pimelic acid, azelaic acid, dimer acid, sebacic acid, suberic acid, and aliphatic dicarboxylic acids such as dodeca dicarboxylic acid. As the polyvalent carboxylic acid, two or more polyvalent carboxylic acids, for example, an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid are often used in combination.

  Various polyhydric alcohols and polyhydric carboxylic acids used for the polyester polymer can be used without particular limitation, and polymer polyols such as polycarbonate diol can be used as the polyhydric alcohol. The polyester polymer can be obtained from the diol component and a trihydric or higher polyhydric alcohol and / or a trivalent or higher polyvalent carboxylic acid. The weight average molecular weight of the polyester polymer is usually 11,000 or more.

<Curable component>
As the radiation or thermosetting component, a monomer and / or oligomer component that undergoes radical polymerization by radiation or heat is used.

  The monomer and / or oligomer component that undergoes radical polymerization includes a monomer and / or oligomer component having an unsaturated double bond such as a (meth) acryloyl group or vinyl group, and the (meth) acryloyl group is particularly advantageous because of its excellent reactivity. Monomer and / or oligomer components having the following are preferably used.

  Specific examples of the monomer component having a (meth) acryloyl group include, for example, monomers used in the acrylic polymer.

  In addition, as an oligomer component that undergoes radical polymerization having a (meth) acryloyl group, an unsaturated double bond such as a (meth) acryloyl group or a vinyl group as a functional group similar to the monomer component on a skeleton such as polyester, epoxy, or urethane. Two or more added polyester (meth) acrylates, epoxy (meth) acrylates, urethane (meth) acrylates, and the like are used. The unsaturated double bond is preferably 2 or more, preferably 4 or more, and more preferably 6 or more. When the number of unsaturated double bonds is larger, the curing component to be contained in the adhesive polymer can be reduced.

  Specific examples of the oligomer component having a (meth) acryloyl group include tripropylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and 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) Of (meth) acrylic acid and polyhydric alcohol such as acrylate, dipentaerythritol hexa (meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) acrylate Ester product, and the like.

  In addition to the above, monomers and / or oligomer components that undergo radical polymerization include 2-propenyl-di-3-butenyl cyanurate, 2-hydroxyethylbis (2-acryloxyethyl) cyanurate, and tris (2-acryloxyethyl). ) Cyanurates or isocyanurate compounds such as isocyanurate and tris (2-methacryloxyethyl) isocyanurate.

  The blending ratio of the adhesive polymer and the curable component is 100 parts by weight of the adhesive polymer from the viewpoint of maintaining the balance between the adhesiveness before curing and the hardness after curing, while maintaining the shape as the adhesive layer before curing. On the other hand, the curable component is preferably 20 to 200 parts by weight, more preferably 50 to 150 parts by weight, and further preferably 60 to 120 parts by weight. In particular, when a curable component having 6 or more unsaturated double bonds is used, the curable component is 100 parts by weight or less, more preferably 90 parts by weight or less, based on 100 parts by weight of the adhesive polymer. The effect of the present invention can also be obtained when used in a small proportion of 80 parts by weight or less.

<Polymerization initiator>
The pressure-sensitive adhesive composition can be used as a radiation or thermosetting pressure-sensitive adhesive composition. When used as a radiation curable pressure-sensitive adhesive composition, when an electron beam is used as radiation, a radiation-cleavage polymerization initiator is not particularly necessary. However, when ultraviolet rays are used as radiation, radiation-cleavage polymerization is used. An initiator is used. When the pressure-sensitive adhesive composition is a thermosetting pressure-sensitive adhesive composition, a heat-cleavable polymerization initiator is used.

  The radiation-cleavage polymerization initiator is appropriately selected depending on the radiation, but when it is cured by ultraviolet rays, an ultraviolet-cleavage polymerization initiator is used. Examples of the ultraviolet cleavage polymerization initiator include benzophenone-based compounds such as benzyl, benzophenone, benzoylbenzoic acid, 3,3′-dimethyl-4-methoxybenzophenone; 4- (2-hydroxyethoxy) phenyl (2-hydroxy 2-propyl) ketone, [alpha] -hydroxy- [alpha], [alpha] '-dimethylacetophenone, 2-methyl-2-hydroxypropiophenone, [alpha] -hydroxycyclohexyl phenyl ketone and other aromatic ketone compounds; methoxyacetophenone, 2,2- Acetophenone compounds such as dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 2-methyl-1- [4- (methylthio) -phenyl] -2-morpholinopropane-1; benzoin methyl Ether, benzoin ethyl ether, Benzoin ether compounds such as benzoin isopropyl ether, benzoin butyl ether and anisoin methyl ether; aromatic ketal compounds such as benzyldimethyl ketal; aromatic sulfonyl chloride compounds such as 2-naphthalenesulfonyl chloride; 1-phenone- Photoactive oxime compounds such as 1,1-propanedione-2- (o-ethoxycarbonyl) oxime; thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthio Thioxane compounds such as xanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, dodecylthioxanthone; camphorquinone; halogenated ketone; Sill phosphino sulfoxide; and acyl phospholipase diisocyanate, and the like.

  The compounding quantity of a radiation cleavage type polymerization initiator is 20 parts weight or less with respect to 100 weight part of adhesive polymers. When ultraviolet rays are used as radiation, the blending amount of the radiation-cleavable polymerization initiator is preferably 0.01 to 20 parts by weight with respect to 100 parts by weight of the adhesive polymer. Furthermore, it is preferable that the said compounding quantity is 0.05-10 weight part, Furthermore, it is 0.1-5 weight part.

  As the thermal cleavage type polymerization initiator, those in which polymerization does not start by thermal cleavage when the pressure-sensitive adhesive layer is formed are preferable. For example, as the thermal cleavage type polymerization initiator, those having a 10-hour half-life temperature of 65 ° C. or higher, more preferably 75 to 90 ° C. are preferable. The half-life is an index representing the decomposition rate of the polymerization initiator, and means the time until the remaining amount of the polymerization initiator is halved. The decomposition temperature for obtaining a half-life at an arbitrary time and the half-life time at an arbitrary temperature are described in the manufacturer catalog, for example, “Organic peroxide catalog 9th edition by Nippon Oil & Fats Co., Ltd.” (May 2003) ".

  Examples of the thermal cleavage type polymerization initiator include lauroyl peroxide (10-hour half-life temperature: 64 ° C.), benzoyl peroxide (10-hour half-life temperature: 73 ° C.), 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane (10-hour half-life temperature: 90 ° C.), di (2-ethylhexyl) peroxydicarbonate (10-hour half-life temperature: 49 ° C.), di (4-t-butyl) Cyclohexyl) peroxydicarbonate, di-sec-butylperoxydicarbonate (10-hour half-life temperature: 51 ° C.), t-butylperoxyneodecanoate (10-hour half-life temperature: 48 ° C.), t-hexyl Peroxypivalate, t-butyl peroxypivalate, dilauroyl peroxide (10 hour half-life temperature: 64 ° C), di-n-octanoylper Xoxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate (10 hour half-life temperature: 66 ° C.), di (4-methylbenzoyl) peroxide, dibenzoyl peroxide (10 hour half) Organic peroxides such as 1,2-di (t-hexylperoxy) cyclohexane, and the like.

  Examples of the thermal cleavage type polymerization initiator include 2,2′-azobisisobutyronitrile (10 hour half-life temperature: 67 ° C.), 2,2′-azobis (2-methylbutyronitrile) ( And azo compounds such as 1,1-azobis-cyclohexane-1-carbonitrile (10-hour half-life temperature: 87 ° C.).

  The blending amount of the thermal cleavage type polymerization initiator is preferably 0.01 to 20 parts by weight with respect to 100 parts by weight of the adhesive polymer with respect to 100 parts by weight of the adhesive polymer. Furthermore, it is preferable that the said compounding quantity is 0.05-10 weight part, Furthermore, it is 0.1-3 weight part.

  The curable pressure-sensitive adhesive layer (B) is, for example, as a pressure-sensitive polymer (base polymer) having a carbon-carbon double bond in the side chain or main chain of the pressure-sensitive polymer, or the main chain, in addition to those described above. It can be formed by using a pressure-sensitive adhesive composition having the terminal and blended with the radiation or thermal cleavage type polymerization initiator. The blending amount of the radiation or thermal cleavage type polymerization initiator is preferably 0.01 to 20 parts by weight as described above with respect to 100 parts by weight of the adhesive polymer. The radiation-cleavage polymerization initiator is blended as necessary according to the type of radiation. The pressure-sensitive adhesive composition does not need to contain a monomer and / or oligomer component, which is a low molecular component, or does not contain a large amount. Therefore, the monomer and / or oligomer component or the like is contained in the pressure-sensitive adhesive composition over time. It is preferable because a pressure-sensitive adhesive layer having a stable layer structure can be formed without moving.

  As the base polymer having a carbon-carbon double bond, those having a carbon-carbon double bond and having adhesiveness can be used without particular limitation. As such a base polymer, an acrylic polymer having a basic skeleton is preferable. Examples of the basic skeleton of the acrylic polymer include the acrylic polymers exemplified above.

  The method for introducing the carbon-carbon double bond into the acrylic polymer is not particularly limited, and various methods can be adopted. However, the carbon-carbon double bond can be introduced into the polymer side chain for easy molecular design. is there. For example, after a monomer having a functional group is copolymerized in advance with an acrylic polymer, a compound having a functional group capable of reacting with the functional group and a carbon-carbon double bond is converted into a radiation-curable carbon-carbon double bond. Examples of the method include condensation or addition reaction while maintaining the above.

  Examples of combinations of these functional groups include carboxylic acid groups and epoxy groups, carboxylic acid groups and aziridyl groups, hydroxyl groups and isocyanate groups. Among these combinations of functional groups, a combination of a hydroxyl group and an isocyanate group is preferable because of easy tracking of the reaction. In addition, the functional group may be on either side of the acrylic polymer and the compound as long as the acrylic polymer having the carbon-carbon double bond is generated by the combination of these functional groups. In the preferable combination, it is preferable that the acrylic polymer has a hydroxyl group and the compound has an isocyanate group. In this case, examples of the isocyanate compound having a carbon-carbon double bond include methacryloyl isocyanate, 2-methacryloyloxyethyl isocyanate, m-isopropenyl-α, α-dimethylbenzyl isocyanate, and the like. Further, as the acrylic polymer, those obtained by copolymerizing the above-exemplified hydroxy group-containing monomers, ether compounds of 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether, or the like are used.

  The curable component (monomer component or oligomer component) can also be added to the pressure-sensitive adhesive composition using the base polymer having a carbon-carbon double bond to such an extent that the characteristics are not deteriorated. The curable component is usually 200 parts by weight or less, preferably 100 parts by weight or less, based on 100 parts by weight of the base polymer.

<Crosslinking agent>
The pressure-sensitive adhesive composition can be blended with a crosslinking agent in order to improve cohesion and the like and to obtain heat resistance and the like. Examples of the crosslinking agent include polyisocyanate compounds, melamine resins, urea resins, epoxy compounds (resins), polyamine compounds, imine compounds, aziridine compounds, organic polyfunctional compounds such as carboxyl group-containing polymers, and polyfunctional metals. Chelate and the like can be mentioned. It is preferable that the compounding quantity of a crosslinking agent is 30 parts weight or less with respect to 100 weight part of adhesive polymers from the point of a softness | flexibility and adhesiveness. The amount of the crosslinking agent is preferably 0.01 to 30 parts by weight, more preferably 0.05 to 20 parts by weight, and still more preferably 0.1 to 10 parts by weight.

  In addition to the above components, the pressure-sensitive adhesive composition includes various tackifiers, antistatic agents, surface lubricants, leveling agents, antioxidants, corrosion inhibitors, light stabilizers, ultraviolet absorbers, and polymerization inhibition. Various additives such as additives, silane coupling agents, inorganic or organic fillers, powders such as metal powders and pigments, particles, and foils can be added as appropriate according to the intended use. .

  The curable pressure-sensitive adhesive layer (B) is formed by laminating on the other surface of the polarizer (P). The lamination method of the curable pressure-sensitive adhesive layer (B) is not particularly limited, and examples thereof include a method of applying and drying the solution of the pressure-sensitive adhesive composition, a method of transferring with a release sheet provided with the pressure-sensitive adhesive layer, and the like. The solution of the pressure-sensitive adhesive composition is prepared, for example, as a solution of about 10 to 40% by weight in which the composition is dissolved or dispersed in a solvent composed of an appropriate solvent alone or a mixture such as toluene and ethyl acetate. . As a coating method, a roll coating method such as reverse coating or gravure coating, a spin coating method, a screen coating method, a fountain coating method, a dipping method, or a spray method can be adopted. In forming the curable pressure-sensitive adhesive layer (B), the curing of the curable component in the pressure-sensitive adhesive composition is prevented from proceeding. For example, when the pressure-sensitive adhesive composition contains a heat-cleavable polymerization initiator, the drying temperature is in a range lower than the cleavage temperature of the heat-cleavable polymerization initiator. As drying temperature of the solution of an adhesive composition, it is 30-60 degreeC normally, Preferably it is 40-50 degreeC.

  The thickness of the curable pressure-sensitive adhesive layer (B) is usually about 3 to 100 μm, preferably 5 to 50 μm, and more preferably 10 to 40 μm.

  As a constituent material of the release sheet, paper, polyethylene, polypropylene, polyethylene terephthalate and other synthetic resin films, rubber sheets, paper, cloth, non-woven fabric, nets, foam sheets and metal foils, and appropriate thin leaf bodies such as laminates thereof Etc. In order to improve the peelability from the pressure-sensitive adhesive layer, the surface of the release sheet may be subjected to a low-adhesive release treatment such as silicone treatment, long-chain alkyl treatment, and fluorine treatment as necessary.

The pressure-sensitive adhesive polarizing plate of the present invention is bonded to the optical display unit via the curable pressure-sensitive adhesive layer (B) of the pressure-sensitive adhesive polarizing plate. When reworking the pressure-sensitive adhesive polarizing plate, the curable pressure-sensitive adhesive layer When (B) is a radiation curable pressure-sensitive adhesive layer, radiation is irradiated and polymerization is started by a radiation-cleavage polymerization initiator, thereby reducing the adhesive strength of the curable pressure-sensitive adhesive layer (B). Examples of radiation include ultraviolet rays, laser beams, α rays, β rays, γ rays, X rays, electron rays, and the like, and ultraviolet rays are preferably used from the viewpoints of controllability, good handleability, and cost. More preferably, ultraviolet rays having a wavelength of 200 to 450 nm are used. Ultraviolet rays can be irradiated using an appropriate light source such as a high-pressure mercury lamp, a microwave excitation lamp, or a chemical lamp. The amount of ultraviolet irradiation is preferably about 100 to 200 mJ / cm ² . When the ultraviolet irradiation amount exceeds 200 mJ / cm ² , the liquid crystal material in the cell may be deteriorated. In order to sufficiently cure the curable pressure-sensitive adhesive layer (B) with such a small amount of ultraviolet irradiation, the one side of the polarizer (P) provided with the curable pressure-sensitive adhesive layer (B) is transparent as in the present invention. It is preferable to provide the curable pressure-sensitive adhesive layer (B) without interposing the protective film (E).

  On the other hand, in the case where the curable pressure-sensitive adhesive layer (B) is a thermosetting pressure-sensitive adhesive layer, by heating, the polymerization is started by the thermal cleavage type polymerization initiator, and the adhesive strength of the curable pressure-sensitive adhesive layer (B). Reduce. Although heating temperature is set according to a thermal cleavage type polymerization initiator, it is about 60-200 degreeC, Preferably it is 80-150 degreeC.

[Other optical layers]
(Formation of surface treatment layer)
In the pressure-sensitive adhesive polarizing plate of the present invention, an optional optical layer can be added to the transparent protective film (E) on the side where the polarizer (P) is not bonded to the adhesive layer (G). As such an optical layer, a hard coat layer, an antireflection treatment, an anti-sticking treatment, or a treatment subjected to treatment for diffusion or anti-glare can be used.

  The hard coat treatment is performed for the purpose of preventing scratches on the polarizing plate surface. For example, the above-mentioned transparent protective film is cured with excellent hardness and sliding properties by an appropriate ultraviolet curable resin such as acrylic or silicone. It can form by the system etc. which are added to the surface of a film (E). The antireflection treatment is performed for the purpose of preventing the reflection of external light on the surface of the polarizing plate, and can be achieved by forming an antireflection film or the like according to the prior art. In addition, the sticking prevention treatment is performed for the purpose of preventing adhesion with an adjacent layer (for example, a backlight-side diffusion plate).

  The anti-glare treatment is applied for the purpose of preventing the outside light from being reflected on the surface of the polarizing plate and obstructing the visibility of the light transmitted through the polarizing plate. For example, the surface is roughened by a sandblasting method or an embossing method. It can be formed by imparting a fine concavo-convex structure to the surface of the transparent protective film (E) by an appropriate method such as a compounding method of transparent fine particles. Examples of the fine particles to be included in the formation of the surface fine concavo-convex structure include conductive materials composed of silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide, and the like having an average particle diameter of 0.5 to 20 μm. In some cases, transparent fine particles such as inorganic fine particles, organic fine particles composed of a crosslinked or uncrosslinked polymer or the like are used. When forming the surface fine uneven structure, the amount of fine particles used is generally about 2 to 70 parts by weight, preferably 5 to 50 parts by weight, based on 100 parts by weight of the transparent resin forming the surface fine uneven structure. The antiglare layer may also serve as a diffusion layer (viewing angle expanding function or the like) for diffusing the light transmitted through the polarizing plate to expand the viewing angle or the like.

[Image display device]
The pressure-sensitive adhesive polarizing plate of the present invention can be preferably used for forming an image display device such as a liquid crystal display device or an organic EL display device.

(Liquid crystal display device)
The liquid crystal display device can be formed according to the conventional method. That is, the liquid crystal display device generally has a liquid crystal cell, a polarizing plate, and, if necessary, appropriate elements such as a diffusion plate, an antiglare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffusion plate, a backlight, and the like. It is formed by arranging one or more parts at appropriate positions and incorporating a drive circuit. The formation of the liquid crystal display device is not particularly limited except that the pressure-sensitive adhesive polarizing plate according to the present invention is used, and can be based on the conventional one. As the liquid crystal cell, any type of liquid crystal cell such as a TN type, STN type, or π type can be used.

  The pressure-sensitive adhesive polarizing plate of the present invention can be installed on one side or both sides of a liquid crystal cell. When providing an adhesive polarizing plate on both sides, they may be the same or different.

[Method for forming liquid crystal display device]
[Conventional Method for Forming Liquid Crystal Display]
By the way, in forming an image display device such as a liquid crystal display device or an organic EL display device, a transparent protective film (E) is laminated only on one side of the polarizer (P) like the pressure-sensitive adhesive polarizing plate of the present invention. In the case of a structure, the stress provided to the film interface of a polarizer (P) may differ in the main surface by which the transparent protective film (E) is laminated | stacked, and the other main surface. That is, since the layer structure is different between the front and back of the polarizer (P), the external stress applied to the polarizer may be different between the front and back of the film. Due to this difference in external stress, the film tends to have a curvature. Such a film that is easily bent is difficult to be processed into an image display device in the conventional manufacturing process as described below.

  As shown conceptually in FIG. 2, the conventional manufacturing process of an image device is roughly divided into a manufacturing process in an optical film manufacturer and a manufacturing process in a panel processing manufacturer. First, an optical film manufacturer manufactures an optical film such as a polarizing plate as a roll material for a long (band-shaped) sheet product (# 1). Next, the original roll is slit to a predetermined size (a size according to the size of the optical display unit) (# 2). Next, the slit raw material is cut to a fixed length in accordance with the size of the optical display unit to be bonded, such as a liquid crystal cell or an organic EL panel (# 3). Next, an appearance inspection is performed on the sheet-like product (optical film) that has been cut into pieces (# 4). Examples of the inspection method include visual defect inspection and inspection using a known defect inspection apparatus. The defect means, for example, surface or internal dirt, scratches, a dent-like defect including a foreign object, an uneven defect, a bubble, a foreign object, or the like. Next, the finished product is inspected (# 5). The finished product inspection is an inspection that complies with quality standards that are more stringent than the appearance inspection. Next, the end surfaces of the four end surfaces of the sheet-like product are processed (# 6). This is performed to prevent the adhesive or the like from protruding from the end face during transportation. Next, in a clean room environment, the single sheet product is clean-wrapped (# 7). Next, packaging for transportation (transport packaging) (# 8). A sheet-like product is manufactured as described above and transported to a panel processing manufacturer.

  The panel processing manufacturer unpacks and disassembles the sheet-like product that has been transported (# 11). Next, an appearance inspection is performed in order to inspect for scratches, dirt, etc. that occur during transportation or at the time of unpacking (# 12). The sheet-like product that has been determined to be non-defective in the inspection is conveyed to the next process. Note that this appearance inspection may be omitted. An optical display unit (for example, a liquid crystal cell which is a glass substrate unit in which a liquid crystal cell is sealed) to which a sheet-like product is bonded is manufactured in advance, and the optical display unit is washed before the bonding step ( # 13).

  Next, the single sheet product and the optical display unit (liquid crystal cell) are bonded together (# 14). The release film is peeled off from the sheet-like product leaving a pressure-sensitive adhesive layer, and the pressure-sensitive adhesive layer is bonded to one surface of the optical display unit as a bonding surface. Further, it can be similarly bonded to the other surface of the optical display unit. In the case of bonding to both, an optical film having the same configuration may be bonded to each surface of the optical display unit, or an optical film having a different configuration may be bonded to each other. Next, the bonded state and defect inspection are performed (# 15). The optical display unit determined to be non-defective in this inspection is transported to the mounting process and mounted on the image display device (# 16). On the other hand, the optical display unit determined to be defective is subjected to a rework process (# 17). In the rework process, the optical film is peeled from the optical display unit. An optical film is newly bonded to the reworked optical display unit (# 14). According to the pressure-sensitive adhesive polarizing plate of the present invention, the rework process in such a process can be easily performed.

  Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to the examples shown below.

[Creating a polarizer]
A polyvinyl alcohol film having an average degree of polymerization of 2700 and a thickness of 75 μm was stretched and conveyed while being dyed between rolls having different peripheral speeds. First, it was immersed in a 30 ° C. water bath for 1 minute to swell the polyvinyl alcohol film and stretched 1.2 times in the conveying direction, and then a 30 ° C. potassium iodide concentration of 0.03% by weight and an iodine concentration of 0.3 By immersing in a weight% aqueous solution for 1 minute, the film was stretched 3 times in the transport direction with reference to a film (original length) that was not stretched at all while dyeing. Next, the film was stretched 6 times based on the original length in the conveying direction while being immersed in an aqueous solution having a boric acid concentration of 4% by weight and a potassium iodide concentration of 5% by weight for 30 seconds. Next, the obtained stretched film was dried at 70 ° C. for 2 minutes to obtain a polarizer. The polarizer had a thickness of 30 μm and a moisture content of 14.3% by weight.

[Preparation of adhesive]
Polyvinyl alcohol resin having an acetoacetyl group (average polymerization degree 1200, saponification degree 98.5% mol%, acetoacetyl group modification degree 5 mol%) 100 parts by weight, 50 parts by weight of methylol melamine at 30 ° C. It melt | dissolved in the pure water under temperature conditions, and prepared the aqueous solution with a solid content density | concentration of 3.7 weight%. A metal colloid-containing adhesive aqueous solution was prepared by adding 18 parts by weight of an aqueous solution containing a positively charged alumina colloid (average particle diameter of 15 nm) at a solid concentration of 10% by weight to 100 parts by weight of this aqueous solution. The viscosity of the adhesive solution was 9.6 mPa · s, the pH was in the range of 4 to 4.5, and the compounding amount of the alumina colloid was 74 parts by weight with respect to 100 parts by weight of the polyvinyl alcohol resin. The average particle diameter of the alumina colloid is measured by a dynamic light scattering method (light correlation method) using a particle size distribution meter (manufactured by Nikkiso, product name “Nanotrack UAP150”).

[Transparent protective film]
A 80 μm thick triacetylcellulose film (trade name “TD-TAC” manufactured by Fuji Film Co., Ltd.) was used.

[Creation of polarizing plate]
A roll machine is applied to one side or both sides of the polarizer with the adhesive applied to one side of the transparent protective film so that the thickness of the adhesive layer after drying is 80 nm. And then dried at 70 ° C. for 6 minutes to prepare a polarizing plate having a transparent protective film on one side or both sides. Hereinafter, the case where a transparent protective film is provided only on one side is referred to as a polarizing plate X, and the case where both names are provided with a transparent protective film is referred to as a polarizing plate Y.

Example 1
[Preparation of curable adhesive]
90 parts by weight of butyl acrylate and 10 parts by weight of acrylic acid were copolymerized in toluene by a conventional method to obtain a solution containing an acrylic copolymer having a weight average molecular weight of 500,000. Dipentaerythritol hexaacrylate (trade name “Kayarad DPHA”, manufactured by Nippon Kayaku Co., Ltd.) having 6 unsaturated double bonds as a curable component with respect to 100 parts by weight of the above solution (solid content) Parts, 5 parts by weight of an ultraviolet-cleavable polymerization initiator (trade name “Irgacure 369”, manufactured by Ciba Specialty Chemicals) and 1 part by weight of a polyisocyanate compound (trade name “Coronate L”, manufactured by Nippon Polyurethane Co., Ltd.) Was added to prepare an acrylic UV curable adhesive solution.

[Formation of adhesive layer]
The acrylic UV curable adhesive solution prepared above is applied to the surface of a release sheet comprising a polyethylene terephthalate film (thickness 38 μm) from which the adhesive solution has been peeled off, so that the thickness after drying is 25 μm. It apply | coated and dried for 10 minutes at 70 degreeC, and the ultraviolet curing adhesive layer was formed.

[Creation of adhesive-type polarizing plate]
The pressure-sensitive adhesive layer formed on the release surface of the release sheet is bonded to the surface of the polarizer of the polarizing plate X (the surface of the polarizer not provided with a transparent protective film), and the pressure-sensitive adhesive layer is transferred. An adhesive polarizing plate was prepared.

Examples 2 and 3
In preparing the curable pressure-sensitive adhesive of Example 1, the acrylic heat was changed in the same manner as in Example 1 except that the amount of dipentaerythritol hexaacrylate used as the curable component was changed as shown in Table 1. A curable adhesive solution was prepared. Further, using the acrylic thermosetting pressure-sensitive adhesive solution, a pressure-sensitive adhesive layer was formed in the same manner as in Example 1 to prepare a pressure-sensitive adhesive polarizing plate.

Example 4
In the preparation of the curable pressure-sensitive adhesive of Example 1, 1,1-azobis-cyclohexane-1-carbonitrile (10 hour half-life temperature) was used as a thermal cleavage type polymerization initiator instead of the ultraviolet cleavage type polymerization initiator. : 87 ° C.) An acrylic thermosetting pressure-sensitive adhesive solution was prepared in the same manner as in Example 1 except that 3 wt. Further, using the acrylic thermosetting pressure-sensitive adhesive solution, a pressure-sensitive adhesive layer was formed in the same manner as in Example 1 to prepare a pressure-sensitive adhesive polarizing plate.

Example 5
In the preparation of the curable pressure-sensitive adhesive of Example 1, a curable component having four unsaturated double bonds (trade name “Shikou UV7550B”, Nippon Synthetic Chemical Co., Ltd.) instead of dipentaerythritol hexaacrylate as a curable component. Acrylic thermosetting pressure-sensitive adhesive solution was prepared in the same manner as in Example 1 except that 5 parts by weight of Co., Ltd.) was blended. Further, using the acrylic thermosetting pressure-sensitive adhesive solution, a pressure-sensitive adhesive layer was formed in the same manner as in Example 1 to prepare a pressure-sensitive adhesive polarizing plate.

Comparative Example 1
In the preparation of the curable pressure-sensitive adhesive of Example 1, an acrylic pressure-sensitive adhesive solution was prepared in the same manner as in Example 1 except that the curable component and the ultraviolet-cleavable polymerization initiator were not blended. Further, using the acrylic pressure-sensitive adhesive solution, a pressure-sensitive adhesive layer was formed in the same manner as in Example 1 to prepare a pressure-sensitive adhesive polarizing plate.

Comparative Example 2
In the preparation of the curable pressure-sensitive adhesive of Example 1, an acrylic pressure-sensitive adhesive solution was prepared in the same manner as in Example 1 except that the curable component and the ultraviolet-cleavable polymerization initiator were not blended. Moreover, the adhesive layer was formed like Example 1 using the said acrylic adhesive solution. Moreover, in producing the adhesive-type polarizing plate, an adhesive layer was formed in the same manner as in Example 1 except that the polarizing plate Y was used instead of the polarizing plate X, and an adhesive-type polarizing plate was produced.

Comparative Example 3
In preparing the pressure-sensitive adhesive polarizing plate of Example 1, a pressure-sensitive adhesive layer was formed in the same manner as in Example 1 except that the polarizing plate Y was used instead of the polarizing plate X, thereby preparing a pressure-sensitive adhesive polarizing plate.

Comparative Example 4
In the preparation of the curable pressure-sensitive adhesive of Example 1, 1,1-azobis-cyclohexane-1-carbonitrile (10 hour half-life temperature) was used as a thermal cleavage type polymerization initiator instead of the ultraviolet cleavage type polymerization initiator. : 87 ° C.) An acrylic thermosetting pressure-sensitive adhesive solution was prepared in the same manner as in Example 1 except that 3 wt. Moreover, the adhesive layer was formed like Example 1 using the said acrylic adhesive solution. Moreover, in producing the adhesive-type polarizing plate, an adhesive layer was formed in the same manner as in Example 1 except that the polarizing plate Y was used instead of the polarizing plate X, and an adhesive-type polarizing plate was produced.

[Preparation of curable adhesive]
In Example 1, an acrylic pressure-sensitive adhesive solution was prepared in the same manner as in Example 1 except that the curable component and the ultraviolet cleavage type polymerization initiator were not blended.

[Formation of adhesive layer]
In Example 1, the acrylic adhesive solution prepared above was used as the adhesive solution, and the polarizing plate prepared above was used as the polarizing plate (one provided with a transparent protective film on both sides). In the same manner as in Example 1, an adhesive polarizing plate was prepared.

  The following evaluation was performed about the adhesion type polarizing plate obtained by the said Example or comparative example. The results are shown in Table 1.

(Adhesive force)
The pressure-sensitive adhesive polarizing plate was cut into a size of 25 mm × 150 mm, and the pressure-sensitive adhesive layer surface was bonded onto a glass plate and left in an environment of 23 ° C./60% RH for 20 minutes or more. The adhesive strength at this time (adhesive strength before curing) was measured. Subsequent to the above, for the Examples, the adhesive strength (adhesive strength after curing) was measured after the adhesive layer was cured. When the pressure-sensitive adhesive layer was an ultraviolet curable pressure-sensitive adhesive layer, ultraviolet rays were irradiated from the polarizing plate side with a metal halide lamp (characteristic wavelength: 410 nm) (irradiation amount: 150 mJ / cm ² ). When the pressure-sensitive adhesive layer was a thermosetting pressure-sensitive adhesive layer, heating was performed at 120 ° C. for 5 minutes during curing.

<Measurement of adhesive strength>
Peel strength when the trigger part of the adhesive polarizing plate on the glass plate is chucked with a variable angle peel tester (manufactured by Asahi Seiko Co., Ltd.) and peeled at a peel angle of 90 ° and a peel speed of 3000 mm / min. (N / 25 mm) was measured. The measurement was carried out in an environment at a temperature of 23 ° C.

(Reworkability)
The pressure-sensitive adhesive polarizing plate prepared as described above was cut to A4 size (210 mm x 300 mm), and the pressure-sensitive adhesive layer surface was bonded to the entire surface of the glass plate and left for 24 hours, and then peeled off by hand. did. In the case where the pressure-sensitive adhesive layer of the pressure-sensitive adhesive polarizing plate is an ultraviolet curable pressure-sensitive adhesive layer (Examples 1 to 3, Comparative Example 3), ultraviolet irradiation (irradiation) is performed from the polarizing plate side with a metal halide lamp (characteristic wavelength 410 nm). Amount: 150 mJ / cm ² ), and when the pressure-sensitive adhesive layer of the pressure-sensitive adhesive polarizing plate is a thermosetting pressure-sensitive adhesive layer (Example 4, Comparative Example 4), heating was further performed at 120 ° C. for 5 minutes. Later, the adhesive optical film was peeled from the glass plate. In Comparative Examples 1 and 2, peeling was performed immediately after the standing. The presence or absence of breakage of the pressure-sensitive adhesive polarizing plate at the time of peeling and the time (minutes) required for peeling the pressure-sensitive adhesive polarizing plate were evaluated.

As shown in Table 1, the pressure-sensitive adhesive polarizing plate of the present invention is a thin pressure-sensitive adhesive polarizing plate having a transparent protective film only on one side of the polarizer, and can satisfy the pressure-sensitive adhesive properties as a pressure-sensitive adhesive polarizing plate, and In addition, the rework can be easily performed without breaking the polarizing plate. In particular, when using those having 6 or more unsaturated double bonds as the curable component as in Examples 1 to 4, the effect of the present invention is achieved even when the curable component is used in a small proportion. Can be obtained. On the other hand, in the case of an adhesive polarizing plate using a thin polarizing plate having a transparent protective film only on one side of the polarizer as in Comparative Example 1, it takes a long time for reworking and the polarizing plate is used for reworking. Destruction occurs. Further, in the case of an adhesive polarizing plate using a polarizing plate having a transparent protective film on both sides of the polarizer as in Comparative Example 2, the polarizing plate can be prevented from being broken during rework, but the rework takes a long time. Cost. Moreover, even when the curable pressure-sensitive adhesive layer of the present invention is formed as in Comparative Examples 3 and 4, in the case of a pressure-sensitive adhesive polarizing plate using a polarizing plate having a transparent protective film on both sides of the polarizer. Because there is one more transparent protective film than a thin polarizing plate, ultraviolet rays are absorbed by the transparent protective film or heat is not easily transmitted by the time the ultraviolet rays reach the curable pressure-sensitive adhesive layer. The adhesive strength of the curable pressure-sensitive adhesive layer cannot be sufficiently reduced, and rework takes time. In addition, by increasing the amount of UV irradiation or increasing the heating temperature, the time required for rework can be shortened by accelerating the curing of the curable pressure-sensitive adhesive layer.
The polarizer and the liquid crystal material in the liquid crystal cell as the adherend are deteriorated.

It is a schematic sectional drawing of the adhesion type polarizing plate by preferable embodiment of this invention. It is a flowchart which shows an example of the manufacturing method of the conventional optical display unit.

Explanation of symbols

P Polarizer E Transparent protective film G Adhesive layer B Curable adhesive layer

Claims (8)

A transparent protective film (E) is provided only on one side of the polarizer (P) via an adhesive layer (G), and on the other side of the polarizer (P), a curable pressure-sensitive adhesive layer (B ) it is provided, and said curable adhesive layer (B), adhesion to glass after curing, I der hereinafter 2N / 25 mm, the curable adhesive layer (B), the adhesive An adhesive-type polarized light characterized by being formed of an adhesive composition containing 20 to 200 parts by weight of a radiation-curable component with respect to 100 parts by weight of an adhesive polymer (excluding urethane-based (meth) acrylate) Board. Pressure-sensitive adhesive composition, relative to the adhesive polymer 100 parts by weight, further, the pressure-sensitive adhesive polarizing plate according to claim 1, further comprising the following radiation-cleavable initiator 20 parts by weight. A transparent protective film (E) is provided only on one side of the polarizer (P) via an adhesive layer (G), and on the other side of the polarizer (P), a curable pressure-sensitive adhesive layer (B ) And the curable pressure-sensitive adhesive layer (B) has an adhesive strength to the glass after curing of 2 N / 25 mm or less, and the curable pressure-sensitive adhesive layer (B) is adhesive. A pressure-sensitive adhesive type formed of a pressure-sensitive adhesive composition containing 20 to 200 parts by weight of a thermosetting component and 0.05 to 20 parts by weight of a thermal cleavage type polymerization initiator with respect to 100 parts by weight of a polymer. Polarizer. The pressure-sensitive adhesive composition according to any one of claims 1 to 3 , further comprising 0.01 to 30 parts by weight of a crosslinking agent with respect to 100 parts by weight of the pressure-sensitive adhesive polymer. The adhesive type polarizing plate according to any one of claims 1 to 4 , wherein the adhesive polymer is an acrylic polymer or a polyester polymer. Curable component, pressure-sensitive adhesive polarizing plate according to claim 1, characterized by having six or more unsaturated double bonds. The image display apparatus which has the adhesion type polarizing plate in any one of Claims 1-6 . A method for manufacturing the image display device according to claim 7 ,
A roll original fabric preparation step of preparing the long sheet of the pressure-sensitive adhesive polarizing plate according to any one of claims 1 to 6 as a roll original fabric,
A sheet cutting process for unwinding the sheet product from the roll and cutting the adhesive polarizing plate into a predetermined size using a cutting means;
After the cutting step, a bonding step of bonding to the optical display unit via the curable pressure-sensitive adhesive layer (B) of the pressure-sensitive adhesive polarizing plate;
A method for manufacturing an image display device having