JP2012226354A - Adhesive type optical film and image display apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive type optical film in which an adhesive layer is laid over at least one side of an optical film, the adhesive type optical film having a high durability under a high temperature environment and able to restrain foam formation in such an environment, even in the case where the optical film on the side on which the adhesive layer is laid is made of a material whose moisture permeability is low.SOLUTION: In the adhesive type optical film, the equilibrium moisture regain (a) of the adhesive layer is 0.5 wt.% or less, and an amount (b) of displacement is 600 μm or less. The equilibrium moisture regain (a) and the amount (b) of displacement satisfy b<1036.4×e. In addition, the adhesive layer is formed from an adhesive agent containing acrylic polymer and cross-linking agent. The optical film is a polarization plate in which at least one side of a polarizer is provided with a transparent protection film. The transparent protection film on the at least one side is formed from a cyclic olefin resin, and the adhesive layer is laid over the transparent protection film.

Description

  The present invention relates to an adhesive optical film in which an adhesive layer is laminated on at least one side of an optical film. The present invention also relates to an image display device such as a liquid crystal display device, an organic EL display device, and a PDP using the adhesive optical film. Examples of the optical film include a polarizing plate, a retardation plate, an optical compensation film, a brightness enhancement film, and a laminate of these.

  In liquid crystal display devices, it is indispensable to dispose polarizing elements on both sides of the liquid crystal cell because of its image forming method. In general, polarizing plates with a transparent protective film bonded to one or both sides of a polarizer are attached. Has been. In addition to polarizing plates, various optical elements have been used for liquid crystal panels in order to improve the display quality of displays. For example, a retardation plate for preventing coloring, a viewing angle widening film for improving the viewing angle of a liquid crystal display, and a brightness enhancement film for increasing the contrast of the display are used. These films are collectively called optical films.

  When sticking the optical film on a liquid crystal cell, an adhesive is usually used. In addition, the adhesion between the optical film and the liquid crystal cell, or the optical film is usually in close contact with each other using an adhesive in order to reduce the loss of light. In such a case, since the adhesive has the merit that a drying step is not required for fixing the optical film, the adhesive is an adhesive optical film provided in advance as an adhesive layer on one side of the optical film. Generally used.

  As a transparent protective film used for the polarizing plate, a triacetyl cellulose film has been awarded. However, triacetyl cellulose does not have sufficient moisture and heat resistance, and when a polarizing plate using a triacetyl cellulose film as a transparent protective film is used at high temperature or high humidity, the performance of the polarizing plate such as the degree of polarization and hue is reduced. There were drawbacks. In addition, the triacetyl cellulose film produces a phase difference with respect to incident light in an oblique direction. Such a phase difference significantly affects the viewing angle characteristics as the size of liquid crystal displays increases in recent years. In order to solve the above problems, a cyclic olefin resin has been proposed as a material for the transparent protective film instead of triacetyl cellulose. Cyclic olefin resin has low moisture permeability and has almost no phase difference in an oblique direction.

  However, the adhesive optical film related to the polarizing plate using the cyclic olefin resin as the material of the transparent protective film is in a high temperature environment in a state where it is bonded to the glass substrate because of the low moisture permeability of the cyclic olefin resin. There is a problem that foaming occurs in the durability to leave. The problem concerning such foaming is a problem that did not occur with triacetyl cellulose as a material for the transparent protective film.

  Examples of a method for controlling the problem related to foaming in the pressure-sensitive adhesive optical film include a saturated water absorption of 0.60% by weight or less and a 90-degree peel adhesive strength to a peel-side adherend of 600 g / 20 mm or less. It has been proposed to use an adhesive layer (Patent Document 1). In Patent Document 1, it is described that foaming can be suppressed by controlling the saturated water absorption rate to be small. However, when a low moisture-permeable cyclic olefin resin is used as the material for the transparent protective film of the polarizing plate, foaming cannot be suppressed simply by reducing the saturated water absorption rate.

JP-A-9-281336

  The present invention is an adhesive optical film in which an adhesive layer is laminated on at least one side of an optical film, and the optical film on the side on which the adhesive layer is laminated is formed of a low moisture-permeable material. Even if it exists, it aims at providing the adhesive optical film which has high durability in a high temperature environment, and can suppress foaming in this environment.

  Another object of the present invention is to provide an image display device using the adhesive optical film.

  As a result of intensive studies to solve the above problems, the present inventors have found the following pressure-sensitive adhesive optical film and completed the present invention.

That is, the present invention is an adhesive optical film in which an adhesive layer is laminated on at least one side of an optical film,
The pressure-sensitive adhesive layer has an equilibrium moisture content (a) of 0.5% by weight or less,
The displacement amount (b) after 1 hour at 23 ° C. when a tensile shear stress of 500 gf is applied at an adhesive area of thickness 25 μm, 10 mm × 10 mm is 600 μm or less,
And the said equilibrium moisture content (a) and the said deviation | shift amount (b) are
b <1036.4 × e ^−5.124a ,
It is related with the adhesion type optical film characterized by satisfying.

  In the pressure-sensitive adhesive optical film, it is preferable that the equilibrium moisture content (a) is 0.02% by weight or more and the deviation amount (b) is 20 μm or more.

  As described above, in the present invention, the pressure-sensitive adhesive layer is controlled from the viewpoint of the equilibrium moisture content (a) and the amount of deviation (b) related to the creep characteristics. Thus, even if the optical film on the side where the pressure-sensitive adhesive layer is laminated is formed of a low moisture-permeable material by controlling the equilibrium moisture content (a) and the amount of deviation (b), Durability in a high temperature environment is increased, and foaming in such an environment can be suppressed.

The pressure-sensitive adhesive layer has an equilibrium moisture content (a) of 0.5% by weight or less. The equilibrium moisture content (a) indicates the amount of moisture finally remaining in the pressure-sensitive adhesive layer, and the lower the amount of moisture finally remaining, the more effective the suppression of foaming. When the equilibrium moisture content (a) exceeds 0.5% by weight, foaming in the durability test cannot be sufficiently suppressed even if the deviation amount (b) is controlled to be small. Further, the amount of deviation (b) related to the creep characteristics is 600 μm or less. When the amount of deviation (b) exceeds 600 μm, foaming in the durability test cannot be sufficiently suppressed even if the equilibrium moisture content (a) is controlled to be small. In addition, the pressure-sensitive adhesive layer of the present invention is controlled so that the equilibrium moisture content (a) and the deviation amount (b) satisfy the above range and b <1036.4 × e− ^5.124a . ing. It is preferable to control the equilibrium moisture content (a) and the deviation amount (b) so that both become small, but by controlling so as to satisfy the above relationship, foaming in the durability test can be suppressed. it can.

  From the viewpoint of suppressing foaming, ideally, the equilibrium moisture content (a) is 0% by weight and the deviation amount (b) is 0 μm. However, the equilibrium moisture content (a) is preferably 0.02% by weight or more, and more preferably 0.03% by weight or more in order to suppress inconvenience due to a decrease in adhesive strength (adhesive strength). In general, the deviation (b) is preferably 20 μm or more. If the amount of deviation (b) is too small, there is a risk that the optical film may be peeled off from the liquid crystal panel in durability tests such as heat resistance and moisture resistance, even if targeted foaming can be suppressed. From this viewpoint, the deviation amount (b) is more preferably 30 μm or more, and further preferably 40 μm or more.

  In the pressure-sensitive adhesive optical film, when the equilibrium moisture content (a) is 0.15% by weight or less, the displacement amount (b) of the pressure-sensitive adhesive layer is preferably 600 μm or less. In particular, when the equilibrium moisture content (a) is 0.15% by weight or less, the deviation amount (b) is preferably 540 μm or less, more preferably 300 μm or less, further 140 μm or less, and even less than 75 μm. Is preferred. Within this range, the equilibrium moisture content (a) is preferably 0.13% by weight or less, more preferably 0.12% by weight or less, and further preferably 0.11% by weight or less.

  In the pressure-sensitive adhesive optical film, when the equilibrium moisture content (a) is more than 0.15% by weight and not more than 0.25% by weight, the deviation amount (b) is 350 μm or less. It is preferable. In particular, when the equilibrium moisture content (a) is more than 0.15% by weight and 0.25% by weight or less, the deviation (b) is preferably 240 μm or less, more preferably 130 μm or less, and even less than 75 μm. Is preferred. Within this range, the equilibrium moisture content (a) is preferably 0.23% by weight or less, more preferably 0.22% by weight or less, and further preferably 0.21% by weight or less.

  In the pressure-sensitive adhesive optical film, when the equilibrium moisture content (a) is more than 0.25% by weight and 0.5% by weight or less, the amount of deviation (b) is 150 μm or less. It is preferable. In particular, when the equilibrium moisture content (a) is more than 0.25 wt% and 0.5 wt% or less, the deviation (b) is preferably 100 μm or less, and more preferably less than 75 μm. . Within such a range, the equilibrium moisture content (a) is preferably 0.45% by weight or less, more preferably 0.43% by weight or less.

  In the pressure-sensitive adhesive optical film, when the equilibrium moisture content (a) is 0.05% by weight or more and 0.25% by weight or less, the adhesive layer has the equilibrium moisture content (a) and the amount of deviation ( b) preferably satisfies b ≦ −541.67a + 209.58. When satisfying such a relationship, it is particularly preferable for suppressing foaming in the durability test. In particular, it is preferable that the relational expression satisfies the equilibrium moisture content (a) in the range of 0.07 to 0.22% by weight.

In the pressure-sensitive adhesive optical film, the optical film on the side where the pressure-sensitive adhesive layer is laminated is 80 ° C., 90% R.D. H. Is suitable when the water vapor transmission rate is 1000 g / m ² · 24 h or less. The present invention is effectively applied when using such a low moisture permeability material, and can suppress foaming in a durability test.

The pressure-sensitive adhesive optical film can be suitably applied when the optical film is a polarizing plate provided with a transparent protective film on at least one surface of a polarizer. In particular, at least one side of the transparent protective film is 80 ° C., 90% R.D. H. Is suitable for the case where the moisture permeability is 1000 g / m ² · 24 h or less and an adhesive layer is laminated on the transparent protective film.

  In the pressure-sensitive adhesive optical film, the pressure-sensitive adhesive layer can be suitably formed of a pressure-sensitive adhesive containing an acrylic polymer and a crosslinking agent.

  The present invention also relates to an image display device using at least one adhesive optical film. The pressure-sensitive adhesive optical film of the present invention is used in combination of one or more sheets depending on various usage modes of an image display device such as a liquid crystal display device.

It is the figure which plotted what satisfy | fills the range of this invention (Example) and what does not satisfy (comparative example) about an adhesive layer.

  The pressure-sensitive adhesive optical film of the present invention is obtained by laminating a pressure-sensitive adhesive layer on at least one surface of an optical film. In addition, the said adhesive layer may provide the single side | surface of the optical film, and may have it on both surfaces of the optical film.

  For the formation of the pressure-sensitive adhesive layer, an appropriate pressure-sensitive adhesive that can satisfy the value of the equilibrium moisture content (a), the value of the deviation amount (b), and the relational expression thereof can be used. There is no limit. Adhesives include rubber adhesives, acrylic adhesives, silicone adhesives, urethane adhesives, vinyl alkyl ether adhesives, polyvinyl alcohol adhesives, polyvinyl pyrrolidone adhesives, polyacrylamide adhesives, Examples thereof include cellulose-based pressure-sensitive adhesives.

  Among these pressure-sensitive adhesives, those having excellent optical transparency, suitable wettability, cohesiveness, and adhesive pressure-sensitive adhesive properties, and excellent weather resistance and heat resistance are preferably used. An acrylic pressure-sensitive adhesive is preferably used as one exhibiting such characteristics. The acrylic pressure-sensitive adhesive is preferable in that it can be designed to have a low equilibrium moisture content (a) and a small shift amount (b).

  The acrylic pressure-sensitive adhesive is based on an acrylic polymer having 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.

  Among the acrylic polymers, from the viewpoint of controlling the equilibrium moisture content (a) to be low, it is preferable that an acrylic polymer having a monomer unit of (meth) acrylic acid alkyl ester having a high hydrophobicity as a main skeleton is used as a base polymer. . In general, (meth) acrylic acid alkyl ester is a linear or branched alkyl group carbon in terms of optical transparency, moderate wettability and cohesion, adhesion, weather resistance and heat resistance. The thing of several 3-9, Preferably the thing of 4-8 is preferably used practically. Among these alkyl groups, the larger the carbon number of the alkyl group, the higher the hydrophobicity, which is preferable for reducing the equilibrium moisture content. Examples of the alkyl (meth) acrylate include butyl (meth) acrylate and isooctyl (meth) acrylate. Among these, isooctyl (meth) acrylate having high hydrophobicity is preferable.

  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.

  In addition, (N-substituted) amides such as (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-butyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methylolpropane (meth) acrylamide, etc. Monomer; (Meth) acrylic acid aminoethyl, (meth) acrylic acid N, N-dimethylaminoethyl, (meth) acrylic acid t-butylaminoethyl (meth) acrylic acid alkylaminoalkyl monomer; (Meth) acrylic acid alkoxyalkyl monomers such as methoxyethyl acid and ethoxyethyl (meth) acrylate; N- (meth) acryloyloxymethylenesuccinimide, N- (meth) acryloyl-6-oxyhexamethylenesuccinimide, N- ( (Meta) acryloyl- -Succinimide monomers such as oxyoctamethylene succinimide and N-acryloylmorpholine; Maleimide monomers such as N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide and N-phenylmaleimide; N-methylitaconimide, N-ethyl Itaconimide monomers such as itaconimide, N-butylitaconimide, N-octylitaconimide, N-2-ethylhexylitaconimide, N-cyclohexylitaconimide, N-laurylitaconimide, etc. are listed as examples of monomers for modification purposes. It is done.

  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.

  Although the ratio of the copolymerization monomer in the acrylic polymer is not particularly limited, it is preferably about 0 to 30%, more preferably about 0.1 to 15% in the weight ratio of all the constituent monomers.

  Among these copolymer monomers, a hydroxyl group-containing monomer, a carboxyl group-containing monomer, and an acid anhydride group-containing monomer are preferably used from the viewpoint of adhesion to a liquid crystal cell and durability for optical film applications. These monomers serve as reaction points with the crosslinking agent. Hydroxyl group-containing monomers, carboxyl group-containing monomers, acid anhydride monomers, and the like are rich in reactivity with intermolecular crosslinking agents, and are preferably used to improve the cohesiveness and heat resistance of the resulting pressure-sensitive adhesive layer. In the case of having such a functional group, since it tends to increase the equilibrium moisture content (a), it is preferable to use one having higher hydrophobicity and high reactivity with a small amount of copolymerization. For example, the hydroxyl group-containing monomer is preferably 4-hydroxybutyl (meth) acrylate, more preferably 6-hydroxyhexyl (meth) acrylate, rather than 2-hydroxyethyl (meth) acrylate. It is preferable to use a hydroxyalkyl group having a large alkyl group. Further, as described above, since the hydroxyl group-containing monomer tends to increase the equilibrium moisture content (a), the minimum use is preferable. When the hydroxyl group-containing monomer is used as a copolymerization monomer, the ratio is all The weight ratio of the constituent monomers is preferably 0.01 to 5%, more preferably 0.01 to 3%. Moreover, when using a carboxyl group-containing monomer as a copolymerization monomer, the ratio is 0.01-10% in the weight ratio of all the constituent monomers, Furthermore, it is preferable that it is 0.01-7%.

  Further, as the copolymer monomer, it is preferable to use a copolymer monomer having high hydrophobicity from the viewpoint of controlling the equilibrium moisture content (a) to be low. For example, maleimide monomers and itaconimide monomers are preferably used as adhesive modification monomers because they have the property of hardly raising the equilibrium moisture content (a) of acrylic polymers obtained by copolymerizing these monomers. .

  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.

  The pressure-sensitive adhesive is preferably a pressure-sensitive adhesive composition containing a crosslinking agent. Examples of the polyfunctional compound that can be blended in the pressure-sensitive adhesive include organic crosslinking agents and polyfunctional metal chelates. Examples of the organic crosslinking agent include an epoxy crosslinking agent, an isocyanate crosslinking agent, an imine crosslinking agent, and a peroxide crosslinking agent. These crosslinking agents can be used alone or in combination of two or more. As the organic crosslinking agent, an isocyanate crosslinking agent is preferable. Moreover, an isocyanate type crosslinking agent is used suitably in combination with a peroxide type crosslinking agent. A polyfunctional metal chelate is one in which a polyvalent metal is covalently or coordinately bonded to an organic compound. Examples of polyvalent metal atoms include Al, Cr, Zr, Co, Cu, Fe, Ni, V, Zn, In, Ca, Mg, Mn, Y, Ce, Sr, Ba, Mo, La, Sn, Ti, and the like. can give. Examples of the atom in the organic compound that is covalently or coordinately bonded include an oxygen atom, and the organic compound includes an alkyl ester, an alcohol compound, a carboxylic acid compound, an ether compound, a ketone compound, and the like.

  The blending ratio of the base polymer such as the acrylic polymer and the crosslinking agent is not particularly limited, but is usually preferably about 0.001 to 20 parts by weight of the crosslinking agent (solid content) with respect to 100 parts by weight of the base polymer (solid content). Furthermore, about 0.01-15 weight part is preferable. As said crosslinking agent, an isocyanate type crosslinking agent and a peroxide type crosslinking agent are preferable. The peroxide crosslinking agent is preferably about 0.02 to 2 parts by weight, more preferably about 0.05 to 1 part by weight, based on 100 parts by weight of the base polymer (solid content). The isocyanate-based crosslinking agent is preferably about 0.001 to 2 parts by weight, more preferably about 0.01 to 1.5 parts by weight with respect to 100 parts by weight of the base polymer (solid content). Moreover, an isocyanate type crosslinking agent and a peroxide type crosslinking agent can be used in the said range, and can be preferably used in combination of these.

  Furthermore, the pressure-sensitive adhesive may include a tackifier, a plasticizer, glass fiber, glass beads, metal powder, other inorganic powders, a pigment, a colorant, a filler, an antioxidant, if necessary. Various additives may be used as appropriate, such as an agent, an ultraviolet absorber, a silane coupling agent, and the like without departing from the object of the present invention. Moreover, it is good also as an adhesive layer etc. which contain microparticles | fine-particles and show light diffusibility.

  As the additive, a silane coupling agent is suitable, and the silane coupling agent (solid content) is preferably about 0.001 to 10 parts by weight with respect to 100 parts by weight of the base polymer (solid content). It is preferable to add about 005 to 5 parts by weight. As the silane coupling agent, those conventionally known can be used without particular limitation. For example, epoxy groups such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, 2- (3,4 epoxycyclohexyl) ethyltrimethoxysilane -Containing silane coupling agent, 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N- (1,3-dimethylbutylidene) propylamine Amino group-containing silane coupling agents such as 3-acryloxypropyltrimethoxysilane, (meth) acrylic group-containing silane coupling agents such as 3-methacryloxypropyltriethoxysilane, and isocyanates such as 3-isocyanatopropyltriethoxysilane Base It can be exemplified a silane coupling agent.

  In order to control the equilibrium moisture content (a) of the pressure-sensitive adhesive layer of the present invention and the amount of deviation (b) so as to satisfy the above range and relationship, for example, the type of base monomer, copolymerization monomer, its blending ratio, It can be performed by controlling the type of the crosslinking agent, the amount thereof, the type of additives, the amount thereof, and the like.

  As described above, from the viewpoint of controlling the equilibrium moisture content (a) of the pressure-sensitive adhesive layer to be low, it is preferable to use a highly hydrophobic monomer. On the other hand, in order to reduce the amount of deviation (b), it is necessary to make it more cohesive. As a method of reducing the deviation amount (b), for example, increasing the molecular weight of the base polymer, copolymerizing a monomer having a high glass transition temperature to the base polymer, or increasing the addition amount of a crosslinking agent to increase the degree of crosslinking. Is applied effectively. As the base polymer, generally, an (meth) acrylic acid alkyl ester is an acrylic polymer composed of a C3-9 monomer unit of a linear or branched alkyl group often used in practice. When used, the larger the carbon number of the alkyl group, the lower the glass transition temperature. In general, an acrylic polymer with low cohesion is obtained, and the amount of deviation (b) tends to increase. Further, it is well known that an acrylic polymer using a carboxyl group-containing monomer such as acrylic acid as a copolymerization monomer greatly contributes to an improvement in cohesiveness of the pressure-sensitive adhesive layer to be formed. ) Tends to be small, but at the same time, the equilibrium moisture content (a) tends to be high. Thus, since the equilibrium moisture content (a) and the amount of deviation (b) have some trade-off relationship, sufficient consideration is required for the selection of the composition. In the present invention, a base monomer (for example, (meth) acrylic acid alkyl ester) and a copolymerization monomer are selected to prepare a base polymer, and the predetermined residual amount is controlled by controlling a saturated moisture content, a blending ratio thereof, and a crosslinking degree. The pressure-sensitive adhesive layer is formed so as to satisfy the moisture content (a) and the deviation amount (b).

  An anchor coat layer may be provided between the pressure-sensitive adhesive layer of the pressure-sensitive adhesive optical film of the present invention and the optical film. The material for forming the anchor coat layer is not particularly limited, but a material that exhibits good adhesion to both the pressure-sensitive adhesive layer and the optical film and forms a film having excellent cohesive force is desirable. Various polymers, metal oxide sols, silica sols, and the like can be used to exhibit such properties. Of these, polymers are particularly preferably used.

  Examples of the polymers include polyurethane resins, polyester resins, and polymers containing amino groups in the molecule. The polymer may be used in any of a solvent-soluble type, a water-dispersed type, and a water-soluble type. For example, water-soluble polyurethane, water-soluble polyester, water-soluble polyamide, etc. and water-dispersible resins (ethylene-vinyl acetate emulsion, (meth) acrylic emulsion, etc.) can be mentioned. The water-dispersed type is obtained by emulsifying various resins such as polyurethane, polyester and polyamide using an emulsifier, or by introducing an anionic group, a cationic group or a nonionic group of a water-dispersible hydrophilic group into the resin. The self-emulsified product can be used. Moreover, an ionic polymer complex can be used.

As the optical film used for the pressure-sensitive adhesive optical film of the present invention, those used for forming an image display device such as a liquid crystal display device are used, and the kind thereof is not particularly limited, but 80 ° C., 90% R.D. H. Application to those having a moisture permeability of 1000 g / m ² · 24 h or less is preferred. The present invention is particularly suitable when the moisture permeability is 800 g / m ² · 24 h or less, further 500 g / m ² · 24 h or less, and further 200 g / m ² · 24 h or less.

  Examples of the material having moisture permeability include, for example, polycarbonate polymer; arylate polymer; polyester polymer such as polyethylene terephthalate and polyethylene naphthalate; amide polymer such as nylon and aromatic polyamide; polyethylene, polypropylene, ethylene / propylene A polyolefin polymer such as a copolymer, a cyclic olefin resin having a cyclo or norbornene structure, or a mixture thereof can be used.

  Moreover, the polymer film described in JP-A-2001-343529 (WO01 / 37007), for example, (A) a thermoplastic resin having a substituted and / or unsubstituted imide group in the side chain, and (B) a substitution in the side chain And / or a resin composition containing a thermoplastic resin having unsubstituted phenyl and a nitrile group. A specific example is a film of a resin composition containing an alternating copolymer composed of isobutylene and N-methylmaleimide and an acrylonitrile / styrene copolymer. As the film, a film made of a mixed extruded product of the resin composition or the like can be used.

  Among the materials, a cyclic olefin resin is preferable. The cyclic olefin-based resin is a general generic name, and is described in, for example, Japanese Patent Application Laid-Open Nos. 3-14882 and 3-122137. Specifically, ring-opening polymers of cyclic olefins, addition polymers of cyclic olefins, random copolymers of cyclic olefins and α-olefins such as ethylene and propylene, and these are modified with unsaturated carboxylic acids or their derivatives. Examples of such graft-modified products can be given. Furthermore, these hydrides are mentioned. The cyclic olefin is not particularly limited, and examples thereof include norbornene, tetracyclododecene, and derivatives thereof. Examples of the products include ZEONEX and ZEONOR manufactured by Nippon Zeon Co., Ltd., Arton manufactured by JSR Corporation, and TOPAS manufactured by TICONA.

  The optical film formed from the low moisture permeability material is used as, for example, a transparent protective film for a polarizer, a retardation film, or the like.

  Examples of the optical film used in the pressure-sensitive adhesive optical film of the present invention include a polarizing plate. A polarizing plate having a transparent protective film on one or both sides of a polarizer is generally used.

  The polarizer is not particularly limited, and various types can be used. Examples of polarizers include dichroic iodine and dichroic dyes on hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and ethylene / vinyl acetate copolymer partially saponified films. Examples thereof include polyene-based oriented films such as those obtained by adsorbing substances and uniaxially stretched, polyvinyl alcohol dehydrated products and polyvinyl chloride dehydrochlorinated products. Among these, a polarizer composed of a polyvinyl alcohol film and a dichroic material such as iodine is preferable. The thickness of these polarizers is not particularly limited, but is generally about 5 to 80 μm.

  A polarizer obtained by dyeing a polyvinyl alcohol film with iodine and uniaxially stretching it can be prepared, for example, by immersing polyvinyl alcohol in an aqueous solution of iodine and stretching it 3 to 7 times the original length. If necessary, it can be immersed in an aqueous solution such as potassium iodide which may contain boric acid, zinc sulfate, zinc chloride or the like. Further, if necessary, the polyvinyl alcohol film may be immersed in water and washed before dyeing. In addition to washing the polyvinyl alcohol film surface with dirt and anti-blocking agents by washing the polyvinyl alcohol film with water, it also has the effect of preventing unevenness such as uneven coloring by swelling the polyvinyl alcohol film. is there. Stretching may be performed after dyeing with iodine, may be performed while dyeing, or may be dyed with iodine after stretching. The film can be stretched even in an aqueous solution such as boric acid or potassium iodide or in a water bath.

  As a material for forming the transparent protective film provided on one side or both sides of the polarizer, a material excellent in transparency, mechanical strength, thermal stability, moisture barrier property, isotropy and the like is preferable. A transparent protective film made of the low moisture permeability material is preferably applied to the side where the pressure-sensitive adhesive layer is bonded, while the other side is made of a material other than the low moisture permeability material, such as diacetyl cellulose. And cellulose polymers such as triacetyl cellulose, acrylic polymers such as polymethyl methacrylate, and styrene polymers such as polystyrene and acrylonitrile / styrene copolymer (AS resin). Also, vinyl chloride polymer, imide polymer, sulfone polymer, polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, polyoxy Examples of the polymer that forms the transparent protective film include methylene-based polymers, epoxy-based polymers, and blends of the polymers. The transparent protective film can also be formed as a cured layer of thermosetting or ultraviolet curable resin such as acrylic, urethane, acrylurethane, epoxy, and silicone.

  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 film property. In particular, 5 to 200 μm is preferable.

  Moreover, it is preferable that a transparent protective film has as little color as possible. Therefore, Rth = (nx−nz) · d (where nx is the refractive index in the slow axis direction in the film plane, nz is the refractive index in the film thickness direction, and d is the film thickness). A transparent protective film having a direction retardation of −90 nm to +75 nm is preferably used. By using a film having a retardation value (Rth) in the thickness direction of −90 nm to +75 nm, the coloring (optical coloring) of the polarizing plate caused by the transparent protective film can be almost eliminated. The thickness direction retardation (Rth) is more preferably -80 nm to +60 nm, and particularly preferably -70 nm to +45 nm.

  In addition, when providing a protective film on both sides of a polarizer, the transparent protective film which consists of the same polymer material may be used by the front and back, and the protective film which consists of a different polymer material etc. may be used. The polarizer and the transparent protective film are usually in close contact with each other through an aqueous adhesive or the like. Examples of the water-based adhesive include an isocyanate-based adhesive, a polyvinyl alcohol-based adhesive, a gelatin-based adhesive, a vinyl-based latex, a water-based polyurethane, and a water-based polyester.

  The surface of the transparent protective film to which the polarizer is not adhered may be subjected to a treatment for the purpose of hard coat layer, antireflection treatment, sticking prevention, diffusion or antiglare.

  The hard coat treatment is applied for the purpose of preventing scratches on the surface of the polarizing plate. For example, a transparent protective film with a cured film excellent in hardness, sliding properties, etc. by an appropriate ultraviolet curable resin such as acrylic or silicone is used. It can be formed by a method of adding to the surface of the film. The antireflection treatment is performed for the purpose of preventing 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 conventional art. Further, the sticking prevention treatment is performed for the purpose of preventing adhesion between adjacent layers of other members.

  Anti-glare treatment is applied for the purpose of preventing external 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 sandblasting or embossing. It can be formed by imparting a fine concavo-convex structure to the surface of the transparent protective film by an appropriate method such as a method or 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 made 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 50 μm. In some cases, transparent fine particles such as inorganic fine particles and organic fine particles (including beads) made of a crosslinked or uncrosslinked polymer are used. When forming a surface fine uneven structure, the amount of fine particles used is generally about 2 to 50 parts by weight, preferably 5 to 25 parts by weight, based on 100 parts by weight of the transparent resin forming the surface fine uneven structure. The anti-glare layer may also serve as a diffusion layer (such as a visual enlargement function) for diffusing the light transmitted through the polarizing plate to enlarge vision.

  The antireflection layer, antisticking layer, diffusion layer, antiglare layer, and the like can be provided on the transparent protective film itself, or can be provided separately from the transparent protective film as an optical layer.

  In addition, as an optical film, for example, it is used for forming a liquid crystal display device such as a reflection plate, an anti-transmission plate, a retardation plate (including wavelength plates such as 1/2 and 1/4), a visual compensation film, and a brightness enhancement film And an optical layer that may be formed. These can be used alone as an optical film, or can be laminated on the polarizing plate for practical use and used as one layer or two or more layers.

  In particular, a reflective polarizing plate or a semi-transmissive polarizing plate in which a polarizing plate is further laminated with a reflecting plate or a semi-transmissive reflecting plate, an elliptical polarizing plate or a circular polarizing plate in which a retardation plate is further laminated on a polarizing plate, a polarizing plate A wide viewing angle polarizing plate in which a visual compensation film is further laminated on a plate, or a polarizing plate in which a luminance enhancement film is further laminated on a polarizing plate is preferable.

  A reflective polarizing plate is a polarizing plate provided with a reflective layer, and is used to form a liquid crystal display device or the like that reflects incident light from the viewing side (display side). Such a light source can be omitted, and the liquid crystal display device can be easily thinned. The reflective polarizing plate can be formed by an appropriate method such as a method in which a reflective layer made of metal or the like is attached to one surface of the polarizing plate via a transparent protective layer or the like as necessary.

  Specific examples of the reflective polarizing plate include those in which a reflective layer is formed by attaching a foil or a vapor deposition film made of a reflective metal such as aluminum on one side of a transparent protective film matted as necessary. In addition, the transparent protective film may contain fine particles to form a surface fine concavo-convex structure, and a reflective layer having a fine concavo-convex structure thereon. The reflective layer having the fine concavo-convex structure has an advantage that incident light is diffused by irregular reflection to prevent directivity and glaring appearance and to suppress unevenness in brightness and darkness. Moreover, the protective film containing fine particles also has an advantage that incident light and its reflected light are diffused when passing through it and light and dark unevenness can be further suppressed. The reflective layer of the fine concavo-convex structure reflecting the surface fine concavo-convex structure of the transparent protective film is formed by, for example, applying metal to the surface of the transparent protective layer by an appropriate method such as a vacuum deposition method, an ion plating method, a sputtering method, or a plating method. It can be performed by a method of attaching directly to the.

  Instead of the method of directly applying the reflecting plate to the transparent protective film of the polarizing plate, the reflecting plate can be used as a reflecting sheet provided with a reflecting layer on an appropriate film according to the transparent film. Since the reflective layer is usually made of metal, the usage form in which the reflective surface is covered with a transparent protective film, a polarizing plate or the like is used to prevent the reflectance from being lowered due to oxidation, and thus to maintain the initial reflectance for a long time. In addition, it is more preferable to avoid a separate attachment of the protective layer.

  The semi-transmissive polarizing plate can be obtained by using a semi-transmissive reflective layer such as a half mirror that reflects and transmits light with the reflective layer. A transflective polarizing plate is usually provided on the back side of a liquid crystal cell, and displays an image by reflecting incident light from the viewing side (display side) when a liquid crystal display device is used in a relatively bright atmosphere. In a relatively dark atmosphere, a liquid crystal display device of a type that displays an image using a built-in power source such as a backlight built in the back side of the transflective polarizing plate can be formed. In other words, the transflective polarizing plate can be used to form liquid crystal display devices that can save energy when using a light source such as a backlight in a bright atmosphere and can be used with a built-in power supply even in a relatively dark atmosphere. It is.

  An elliptically polarizing plate or a circularly polarizing plate in which a retardation plate is further laminated on a polarizing plate will be described. A phase difference plate or the like is used when changing linearly polarized light to elliptically polarized light or circularly polarized light, changing elliptically polarized light or circularly polarized light to linearly polarized light, or changing the polarization direction of linearly polarized light. In particular, a so-called quarter-wave plate (also referred to as a λ / 4 plate) is used as a retardation plate that changes linearly polarized light into circularly polarized light or changes circularly polarized light into linearly polarized light. A half-wave plate (also referred to as a λ / 2 plate) is usually used when changing the polarization direction of linearly polarized light.

  The elliptically polarizing plate is effectively used for black and white display without the above color by compensating (preventing) the coloration (blue or yellow) generated by the birefringence of the liquid crystal layer of the super twist nematic (STN) type liquid crystal display device. It is done. Further, the one in which the three-dimensional refractive index is controlled is preferable because it can compensate (prevent) coloring that occurs when the screen of the liquid crystal display device is viewed from an oblique direction. The circularly polarizing plate is effectively used, for example, when adjusting the color tone of an image of a reflective liquid crystal display device in which an image is displayed in color, and also has an antireflection function.

  Examples of the retardation plate include a birefringent film obtained by uniaxially or biaxially stretching a polymer material, a liquid crystal polymer alignment film, and a liquid crystal polymer alignment layer supported by a film. The thickness of the retardation plate is not particularly limited, but is generally about 20 to 150 μm.

  Examples of the polymer material include polyvinyl alcohol, polyvinyl butyral, polymethyl vinyl ether, polyhydroxyethyl acrylate, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, polycarbonate, polyarylate, polysulfone, polyethylene terephthalate, polyethylene naphthalate, polyether sulfone, Polyphenylene sulfide, polyphenylene oxide, polyallylsulfone, polyamide, polyimide, polyolefin, polyvinyl chloride, cellulose polymer, norbornene resin, or binary, ternary copolymers, graft copolymers, Examples include blends. These polymer materials become an oriented product (stretched film) by stretching or the like.

  Examples of the liquid crystal polymer include various main chain types and side chain types in which a conjugated linear atomic group (mesogen) imparting liquid crystal alignment is introduced into the main chain or side chain of the polymer. . Specific examples of the main chain type liquid crystal polymer include a nematic alignment polyester liquid crystal polymer, a discotic polymer, and a cholesteric polymer having a structure in which a mesogen group is bonded at a spacer portion that imparts flexibility. Specific examples of the side chain type liquid crystal polymer include polysiloxane, polyacrylate, polymethacrylate, or polymalonate as a main chain skeleton, and a nematic alignment-providing para-substitution via a spacer portion composed of a conjugated atomic group as a side chain. Examples thereof include those having a mesogenic part composed of a cyclic compound unit. These liquid crystal polymers can be prepared by, for example, applying a solution of a liquid crystalline polymer on an alignment surface such as a surface of a thin film such as polyimide or polyvinyl alcohol formed on a glass plate, or an oblique deposition of silicon oxide. This is done by developing and heat treatment.

  The retardation plate may have an appropriate retardation according to the purpose of use, such as for the purpose of compensating for coloring, vision, etc. due to birefringence of various wave plates and liquid crystal layers, and may be two or more types. It may be one in which retardation plates are stacked and optical characteristics such as retardation are controlled.

  The elliptical polarizing plate and the reflective elliptical polarizing plate are obtained by laminating a polarizing plate or a reflective polarizing plate and a retardation plate in an appropriate combination. Such an elliptically polarizing plate or the like can also be formed by sequentially laminating them sequentially in the manufacturing process of the liquid crystal display device so as to be a combination of a (reflective) polarizing plate and a retardation plate. An optical film such as a polarizing plate has an advantage that it can improve the production efficiency of a liquid crystal display device and the like because of excellent quality stability and lamination workability.

  The visual compensation film is a film for widening the viewing angle so that the image can be seen relatively clearly even when the screen of the liquid crystal display device is viewed from a slightly oblique direction rather than perpendicular to the screen. Examples of such a visual compensation phase difference plate include a phase difference plate, an alignment film such as a liquid crystal polymer, and a film in which an alignment layer such as a liquid crystal polymer is supported on a transparent substrate. A normal retardation plate uses a birefringent polymer film that is uniaxially stretched in the plane direction, whereas a retardation plate used as a visual compensation film is biaxially stretched in the plane direction. Birefringent polymer film, biaxially stretched film such as polymer with birefringence with a controlled refractive index in the thickness direction that is uniaxially stretched in the plane direction and stretched in the thickness direction, etc. Used. Examples of the inclined alignment film include a film obtained by bonding a heat shrink film to a polymer film and stretching or / and shrinking the polymer film under the action of the contraction force by heating, and a film obtained by obliquely aligning a liquid crystal polymer. can give. The raw material polymer for the phase difference plate is the same as the polymer described in the previous phase difference plate, preventing coloration due to a change in the viewing angle based on the phase difference by the liquid crystal cell and expanding the viewing angle for good visual recognition. An appropriate one for the purpose can be used.

  In addition, from the viewpoint of achieving a wide viewing angle with good visibility, an optical compensation position 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. A phase difference plate can be preferably used.

  A polarizing plate obtained by bonding a polarizing plate and a brightness enhancement film is usually provided on the back side of a liquid crystal cell. The brightness enhancement film reflects a linearly polarized light with a predetermined polarization axis or a circularly polarized light in a predetermined direction when natural light is incident due to a backlight such as a liquid crystal display device or reflection from the back side, and transmits other light. In addition, a polarizing plate in which a brightness enhancement film is laminated with a polarizing plate allows light from a light source such as a backlight to enter to obtain transmitted light in a predetermined polarization state, and reflects light without transmitting the light other than the predetermined polarization state. The The light reflected on the surface of the brightness enhancement film is further inverted through a reflective layer or the like provided behind the brightness enhancement film and re-incident on the brightness enhancement film, and part or all of the light is transmitted as light having a predetermined polarization state. Luminance can be improved by increasing the amount of light transmitted through the enhancement film and increasing the amount of light that can be used for liquid crystal display image display or the like by supplying polarized light that is difficult to be absorbed by the polarizer. That is, when light is incident through the polarizer from the back side of the liquid crystal cell without using a brightness enhancement film, light having a polarization direction that does not coincide with the polarization axis of the polarizer is almost polarized. It is absorbed by the polarizer and does not pass through the polarizer. That is, although depending on the characteristics of the polarizer used, approximately 50% of the light is absorbed by the polarizer, and accordingly, the amount of light that can be used for liquid crystal image display or the like is reduced and the image becomes dark. The brightness enhancement film reflects light that has a polarization direction that is absorbed by the polarizer without being incident on the polarizer, and is reflected by the brightness enhancement film, and then inverted through a reflective layer or the like provided behind the brightness enhancement film. The brightness enhancement film transmits only the polarized light in which the polarization direction of the light reflected and inverted between the two is allowed to pass through the polarizer. Since the light is supplied to the polarizer, light such as a backlight can be efficiently used for displaying an image on the liquid crystal display device, and the screen can be brightened.

  A diffusion plate may be provided between the brightness enhancement film and the reflective layer. The polarized light reflected by the brightness enhancement film is directed to the reflective layer or the like, but the installed diffuser plate uniformly diffuses the light passing therethrough and simultaneously cancels the polarized state and becomes a non-polarized state. That is, the light in the natural light state is directed toward the reflection layer or the like, reflected through the reflection layer or the like, and again passes through the diffusion plate and reenters the brightness enhancement film. In this way, by providing a diffuser plate that returns polarized light to the original natural light between the brightness enhancement film and the reflective layer, the brightness of the display screen is maintained, and at the same time, the brightness of the display screen is reduced and uniform. Can provide a bright screen. By providing such a diffuser plate, it is considered that the first incident light has a moderate increase in the number of repetitions of reflection, and in combination with the diffusion function of the diffuser plate, a uniform bright display screen can be provided.

  The brightness enhancement film has a characteristic of transmitting linearly polarized light having a predetermined polarization axis and reflecting other light, such as a multilayer thin film of dielectric material or a multilayer laminate of thin film films having different refractive index anisotropies. Such as an alignment film of a cholesteric liquid crystal polymer or an alignment liquid crystal layer supported on a film substrate, which reflects either left-handed or right-handed circularly polarized light and transmits other light. Appropriate things such as a thing can be used.

  Therefore, in the brightness enhancement film of the type that transmits linearly polarized light having the predetermined polarization axis as described above, the transmitted light is incident on the polarizing plate with the polarization axis aligned as it is, thereby efficiently transmitting while suppressing absorption loss due to the polarizing plate. Can be made. On the other hand, in a brightness enhancement film of a type that transmits circularly polarized light such as a cholesteric liquid crystal layer, it can be incident on a polarizer as it is, but from the point of suppressing absorption loss, the circularly polarized light is converted into linearly polarized light through a retardation plate. It is preferably incident on the polarizing plate. Note that circularly polarized light can be converted to linearly polarized light by using a quarter wave plate as the retardation plate.

  A retardation plate that functions as a quarter-wave plate at a wide wavelength in the visible light region or the like exhibits, for example, a retardation plate that functions as a quarter-wave plate for light-colored light having a wavelength of 550 nm and other retardation characteristics. It can be obtained by a method in which a phase difference layer, for example, a phase difference layer that functions as a half-wave plate is superimposed. Therefore, the retardation plate disposed between the polarizing plate and the brightness enhancement film may be composed of one or more retardation layers.

  In addition, a cholesteric liquid crystal layer having a reflection structure that reflects circularly polarized light in a wide wavelength range such as a visible light range can be obtained by combining two or more layers with different reflection wavelengths to form an overlapping structure. Based on this, transmitted circularly polarized light in a wide wavelength range can be obtained.

  Further, the polarizing plate may be formed by laminating a polarizing plate and two or more optical layers as in the above-described polarization separation type polarizing plate. Therefore, a reflective elliptical polarizing plate or a semi-transmissive elliptical polarizing plate in which the above-described reflective polarizing plate or semi-transmissive polarizing plate and a retardation plate are combined may be used.

  An optical film in which the optical layer is laminated on a polarizing plate can be formed by a method of sequentially laminating separately in the manufacturing process of a liquid crystal display device or the like. There is an advantage that the manufacturing process of a liquid crystal display device or the like can be improved because of excellent stability and assembly work. For the lamination, an appropriate adhesive means such as an adhesive layer can be used. When bonding the polarizing plate and the other optical layer, their optical axes can be set at an appropriate arrangement angle in accordance with the target retardation characteristics.

  Next, a method for producing an adhesive optical film will be described. The method for forming the pressure-sensitive adhesive layer is not particularly limited, and examples thereof include a method of applying a pressure-sensitive adhesive solution on the optical film and drying, a method of transferring with a release sheet provided with the pressure-sensitive adhesive layer, and the like. 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. Although the thickness of an adhesive layer is not specifically limited, It is preferable to set it as about 10-40 micrometers.

  When providing an anchor coat layer, an adhesive layer is formed after forming an anchor coat layer on the optical film. For example, a solution of an anchor component such as a polyethyleneimine aqueous solution is applied and dried using a coating method such as a coating method, a dipping method, or a spray method to form an anchor coat layer. The thickness of the anchor coat layer is preferably about 10 to 5000 nm, more preferably in the range of 50 to 500 nm. When the thickness of the anchor coat layer is reduced, the anchor coat layer does not have bulk properties, does not exhibit sufficient strength, and sufficient adhesion may not be obtained. Moreover, when too thick, there exists a possibility of causing the fall of an optical characteristic.

  In forming the pressure-sensitive adhesive layer or the like, the optical film can be activated. Various methods can be employed for the activation treatment, such as corona treatment, low-pressure UV treatment, plasma treatment, and the like. Further, an antistatic layer can be appropriately formed.

  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.

  In addition, each layer such as an optical film or an adhesive layer of the pressure-sensitive adhesive optical film of the present invention includes, for example, an ultraviolet ray such as a salicylic acid ester compound, a benzophenol compound, a benzotriazole compound, a cyanoacrylate compound, or a nickel complex compound. What gave the ultraviolet absorptivity by systems, such as a system processed with an absorber, may be used.

  The pressure-sensitive adhesive optical film of the present invention can be preferably used for forming various image display devices such as liquid crystal display devices. The liquid crystal display device can be formed according to the conventional method. That is, a liquid crystal display device is generally formed by appropriately assembling components such as a liquid crystal cell, an adhesive optical film, and an illumination system as necessary, and incorporating a drive circuit. There is no particular limitation except that an adhesive optical film is used. As the liquid crystal cell, an arbitrary type such as an arbitrary type such as a TN type, an STN type, or a π type can be used.

  An appropriate liquid crystal display device such as a liquid crystal display device in which an adhesive optical film is disposed on one side or both sides of a liquid crystal cell, or a backlight or a reflector used in an illumination system can be formed. In that case, the optical film according to the present invention can be installed on one side or both sides of the liquid crystal cell. When optical films are provided on both sides, they may be the same or different. Further, when forming a liquid crystal display device, for example, a single layer or a suitable part such as a diffusing plate, an antiglare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffusing plate, a backlight, etc. Two or more layers can be arranged.

  Next, an organic electroluminescence device (organic EL display device) will be described. The optical film (polarizing plate or the like) of the present invention can also be applied to an organic EL display device. Generally, in an organic EL display device, a transparent electrode, an organic light emitting layer, and a metal electrode are sequentially laminated on a transparent substrate to form a light emitter (organic electroluminescent light emitter). Here, the organic light emitting layer is a laminate of various organic thin films, for example, a laminate of a hole injection layer made of a triphenylamine derivative and the like and a light emitting layer made of a fluorescent organic solid such as anthracene, Alternatively, a structure having various combinations such as a laminate of such a light-emitting layer and an electron injection layer composed of a perylene derivative or the like, or a laminate of these hole injection layer, light-emitting layer, and electron injection layer is known. It has been.

  In organic EL display devices, holes and electrons are injected into the organic light-emitting layer by applying a voltage to the transparent electrode and the metal electrode, and the energy generated by recombination of these holes and electrons excites the phosphor material. Then, light is emitted on the principle that the excited fluorescent material emits light when returning to the ground state. The mechanism of recombination in the middle is the same as that of a general diode, and as can be predicted from this, the current and the emission intensity show strong nonlinearity with rectification with respect to the applied voltage.

  In an organic EL display device, in order to extract light emitted from the organic light emitting layer, at least one of the electrodes must be transparent, and a transparent electrode usually formed of a transparent conductor such as indium tin oxide (ITO) is used as an anode. It is used as. On the other hand, in order to facilitate electron injection and increase luminous efficiency, it is important to use a material having a small work function for the cathode, and usually metal electrodes such as Mg—Ag and Al—Li are used.

  In the organic EL display device having such a configuration, the organic light emitting layer is formed of a very thin film having a thickness of about 10 nm. For this reason, the organic light emitting layer transmits light almost completely like the transparent electrode. As a result, light that is incident from the surface of the transparent substrate at the time of non-light emission, passes through the transparent electrode and the organic light emitting layer, and is reflected by the metal electrode is again emitted to the surface side of the transparent substrate. The display surface of the organic EL display device looks like a mirror surface.

  In an organic EL display device comprising an organic electroluminescent light emitting device comprising a transparent electrode on the surface side of an organic light emitting layer that emits light upon application of a voltage and a metal electrode on the back side of the organic light emitting layer, the surface of the transparent electrode While providing a polarizing plate on the side, a retardation plate can be provided between the transparent electrode and the polarizing plate.

  Since the retardation plate and the polarizing plate have a function of polarizing light incident from the outside and reflected by the metal electrode, there is an effect that the mirror surface of the metal electrode is not visually recognized by the polarization action. In particular, the mirror surface of the metal electrode can be completely shielded by configuring the retardation plate with a quarter-wave plate and adjusting the angle formed by the polarization direction of the polarizing plate and the retardation plate to π / 4. .

  That is, only the linearly polarized light component of the external light incident on the organic EL display device is transmitted by the polarizing plate. This linearly polarized light becomes generally elliptically polarized light by the phase difference plate, but becomes circularly polarized light particularly when the phase difference plate is a quarter wavelength plate and the angle between the polarization direction of the polarizing plate and the phase difference plate is π / 4. .

  This circularly polarized light is transmitted through the transparent substrate, the transparent electrode, and the organic thin film, is reflected by the metal electrode, is again transmitted through the organic thin film, the transparent electrode, and the transparent substrate, and becomes linearly polarized light again on the retardation plate. And since this linearly polarized light is orthogonal to the polarization direction of a polarizing plate, it cannot permeate | transmit a polarizing plate. As a result, the mirror surface of the metal electrode can be completely shielded.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In addition, all the parts and% in each example are based on weight.

(Moisture permeability)
It measured according to the moisture permeability test (cup method) of JIS Z0208. A sample cut to a diameter of 60 mm is set in a moisture permeable cup containing about 15 g of calcium chloride, placed in a thermostat at 80 ° C. and 90%, and the weight increase of calcium chloride before and after standing for 24 hours is measured. Wet (g / m ² · 24 h) was determined.

(Preparation of polarizing plate)
A 80 μm-thick polyvinyl alcohol film was stretched three times in an aqueous 0.3% iodine solution at 30 ° C. between rolls having different speed ratios. Subsequently, the film was stretched at 60 ° C. in an aqueous solution containing 4% strength boric acid and 10% strength potassium iodide to a total stretch ratio of 6 times. Next, the film was washed by dipping in a 1.5% strength potassium iodide aqueous solution at 30 ° C. for 10 seconds, and then dried at 50 ° C. for 4 minutes to obtain a polarizer. On one side of this polarizer, a saponified 80 μm thick triacetyl cellulose film was bonded with a polyvinyl alcohol-based adhesive. On the other surface of the polarizer, a 70 μm-thick cyclic olefin resin film (manufactured by Nippon Zeon Co., Ltd., trade name “Zeonor”) was bonded with a polyvinyl alcohol adhesive. The cyclic olefin-based resin film at 80 ° C. and 90% R.D. H. The water vapor transmission rate was 127 g / m ² · 24 h.

Example 1
(Preparation of adhesive)
In a reaction vessel equipped with a cooling tube, a nitrogen introduction tube, a thermometer and a stirrer, 100 parts of butyl acrylate, 5 parts of acrylic acid, 0.075 part of 2-hydroxyethyl acrylate and 2,2′-azobisisobutyrate A solution was prepared by adding 0.3 parts of ronitrile with ethyl acetate. Next, the solution was stirred while blowing nitrogen gas and reacted at 60 ° C. for 4 hours to obtain a solution containing an acrylic polymer having a weight average molecular weight of 2.2 million. Furthermore, the acrylic polymer solution (A) which added ethyl acetate to the solution containing this acrylic polymer and adjusted solid content concentration to 30% was obtained.

  For 100 parts of the solid content of the acrylic polymer solution (A), as a crosslinking agent, a crosslinking agent mainly composed of a compound having an isocyanate group of 0.6 part (made by Nippon Polyurethane Co., Ltd., trade name “Coronate” L ") and 0.075 parts of γ-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name" KMB-403 ") as a silane coupling agent in this order, An adhesive solution was prepared.

(Preparation of adhesive optical film)
The above pressure-sensitive adhesive solution is uniformly coated with a fountain coater on the surface of a separator made of a polyethylene terephthalate film surface-treated with a silicone release agent, and dried in an air-circulating constant temperature oven at 155 ° C. for 3 minutes. An adhesive layer having a thickness of 25 μm was formed. A separator having an adhesive layer formed thereon was transferred to one side of the polarizing plate (on the side of the cyclic olefin resin film) to prepare an adhesive polarizing plate.

Example 2, Comparative Examples 1-2
In Example 1, a pressure-sensitive adhesive solution was prepared in the same manner as in Example 1 except that the blending amount of the crosslinking agent mainly composed of a compound having an isocyanate group was changed as shown in Table 1. In addition, an adhesive polarizing plate was produced in the same manner as in Example 1.

Comparative Example 3
In Example 1, an acrylic polymer solution (A ′) having a solid content concentration adjusted to 30% was obtained in the same manner as in Example 1 except that the amount of acrylic acid used was changed from 5 parts to 8 parts. It was.

  For 100 parts of the solid content of the acrylic polymer solution (A ′), as a crosslinking agent, a crosslinking agent mainly comprising a compound having an isocyanate group of 0.8 part (manufactured by Nippon Polyurethane Co., Ltd., trade name “ Coronate L ”) and 0.075 parts of γ-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name“ KMB-403 ”) as a silane coupling agent were blended in this order. A pressure-sensitive adhesive solution was prepared. Using the adhesive solution, an adhesive polarizing plate was produced in the same manner as in Example 1.

Example 3
(Preparation of adhesive)
In a reaction vessel equipped with a cooling pipe, a nitrogen introduction pipe, a thermometer and a stirrer, 99 parts of butyl acrylate, 1.0 part of 4-hydroxybutyl acrylate and 2,2′-azobisisobutyronitrile 0.3 A portion was added with ethyl acetate to prepare a solution. Next, this solution was stirred while blowing nitrogen gas and reacted at 60 ° C. for 4 hours to obtain a solution containing an acrylic polymer having a weight average molecular weight of 1,650,000. Furthermore, the acrylic polymer solution (B) which added ethyl acetate to the solution containing this acrylic polymer and adjusted solid content concentration to 30% was obtained.

  Peroxide-based cross-linking agent containing 0.3 part of dibenzoyl peroxide as a cross-linking agent with respect to 100 parts of solid content of the acrylic polymer solution (B) (Nippon Yushi Co., Ltd., trade name “Nyper” BO-Y ") and 0.18 parts trimethylolpropane xylene diisocyanate (Mitsui Takeda Chemical Co., Ltd., trade name" Takenate D110N ") and 0.2 parts silane coupling agent containing acetoacetyl group (Soken Chemical) Co., Ltd., trade name “A-100”) was blended in this order to prepare an adhesive solution. In addition, an adhesive polarizing plate was produced in the same manner as in Example 1.

Examples 4-5, Comparative Examples 4-5
In Example 3, the pressure-sensitive adhesive was the same as Example 3 except that the compounding amounts of the crosslinking agent having a compound having an isocyanate group as a main component and the peroxide-based crosslinking agent were changed as shown in Table 1. A solution was prepared. In addition, an adhesive polarizing plate was produced in the same manner as in Example 1. In addition, an adhesive polarizing plate was produced in the same manner as in Example 1.

Example 6
(Preparation of adhesive)
In a reaction vessel equipped with a cooling tube, a nitrogen introduction tube, a thermometer and a stirrer, 100 parts of isooctyl acrylate, 0.075 part of 6-hydroxyhexyl acrylate, and 2,2′-azobisisobutyronitrile 0.3 A portion was added with ethyl acetate to prepare a solution. Next, the solution was stirred while blowing nitrogen gas and reacted at 60 ° C. for 4 hours to obtain a solution containing an acrylic polymer having a weight average molecular weight of 1,750,000. Furthermore, the acrylic polymer solution (C) which added ethyl acetate to the solution containing this acrylic polymer and adjusted solid content concentration to 30% was obtained.

  For 100 parts of the solid content of the acrylic polymer solution (C), as a crosslinking agent, a crosslinking agent mainly composed of a compound having 2.5 parts of an isocyanate group (trade name “Coronate” manufactured by Nippon Polyurethane Co., Ltd.) L ”) and 0.01 part of γ-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name“ KMB-403 ”) as a silane coupling agent, An adhesive solution was prepared. In addition, an adhesive polarizing plate was produced in the same manner as in Example 1.

Examples 7-9, Comparative Example 6
In Example 6, a pressure-sensitive adhesive solution was prepared in the same manner as in Example 6 except that the blending amount of the crosslinking agent containing a compound having an isocyanate group as a main component was changed as shown in Table 1. In addition, an adhesive polarizing plate was produced in the same manner as in Example 1.

  The following evaluation was performed about the adhesive optical film (adhesive polarizing plate) obtained by the said Example and comparative example. The evaluation results are shown in Table 1.

<Equilibrium moisture content (%)>
The pressure-sensitive adhesive layer was cut into 300 mm × 240 mm (about 1.5 g) and folded to form a lump of pressure-sensitive adhesive layer as a sample. This sample was placed on the sample board after the weight of the aluminum foil was measured. The sample produced by this method was put into a heating oven and the moisture content was determined. The measurement conditions were a nitrogen cylinder flow rate of 300 ml / min, a nitrogen flow rate in the apparatus of 200 ml / min, and a heating oven at 110 ° C. The measured value is measured to the point where the drift value is +0.1 μg / s, the total moisture content is measured, and the equilibrium moisture content (%): (total moisture content / weight of adhesive layer) × 100 is obtained. (Karl-Fischer moisture meter).

<Creep test: Deviation amount (μm)>
A sample obtained by cutting an adhesive layer having a thickness of 25 μm into a width of 10 mm × 30 mm was used as a sample. The upper 10 mm × 10 mm of this sample was attached to a bake plate, autoclaved for 15 minutes at 50 ° C. and 50 atm, and then left at room temperature (23 ° C.) for 1 hour. Thereafter, a load of 500 g was applied to the sample (load of tensile shear stress in the drooping direction), and the amount of deviation (μm) of the sample after 1 hour was measured.

<Foaming test>
An adhesive optical film (15-inch sample) was attached to both surfaces of a non-alkali glass plate having a thickness of 0.07 mm so as to be in a crossed Nicol state. Next, autoclaving was performed at 50 ° C. and 5 atm for 15 minutes to achieve complete adhesion. After the sample was treated for 500 hours at 80 ° C., the state of foaming was observed according to the following criteria. For the observation of foaming, the number of foams in four corner areas (50 mm × 50 mm) of a 15-inch sample was measured with a polarizing microscope.
○: No foaming occurred.
Δ: Foaming number is less than 100.
X: The foaming number is 100 or more.

These are shown in FIG. 1 for the obtained results. The plot in FIG. 1 corresponds to each example, and the plot uses symbols related to evaluation in the foam test.

Claims (10)

In an adhesive optical film in which an adhesive layer is laminated on at least one side of the optical film,
The pressure-sensitive adhesive layer has an equilibrium moisture content (a) of 0.5% by weight or less,
The displacement amount (b) after 1 hour at 23 ° C. when a tensile shear stress of 500 gf is applied at an adhesive area of thickness 25 μm, 10 mm × 10 mm is 600 μm or less,
And the said equilibrium moisture content (a) and the said deviation | shift amount (b) are
b <1036.4 × e ^−5.124a ,
Satisfied, and
The pressure-sensitive adhesive layer is formed of a pressure-sensitive adhesive containing an acrylic polymer and a crosslinking agent,
The optical film is a polarizing plate provided with a transparent protective film on at least one side of a polarizer, and the transparent protective film on at least one side is formed of a cyclic olefin-based resin, and the adhesive layer is formed on the transparent protective film. An adhesive optical film characterized by being laminated.   The pressure-sensitive adhesive optical film according to claim 1, wherein the equilibrium moisture content (a) is 0.02% by weight or more, and the deviation (b) is 20 µm or more. The pressure-sensitive adhesive layer has an equilibrium moisture content (a) of 0.15% by weight or less, and
The pressure-sensitive adhesive optical film according to claim 1 or 2, wherein the deviation (b) is 600 µm or less. The pressure-sensitive adhesive layer has an equilibrium moisture content (a) of more than 0.15% by weight and 0.25% by weight or less,
And the amount of deviation (b) is 350 micrometers or less, The adhesion type optical film according to claim 1 or 2 characterized by things. The pressure-sensitive adhesive layer has an equilibrium moisture content (a) of more than 0.25 wt% and 0.5 wt% or less,
And the amount of deviation (b) is 150 micrometers or less, The adhesion type optical film according to claim 1 or 2 characterized by things. The pressure-sensitive adhesive layer has an equilibrium moisture content (a) of 0.05 wt% or more and 0.25 wt% or less,
And the said equilibrium moisture content (a) and the said deviation | shift amount (b) are
b ≦ −541.67a + 209.58,
The pressure-sensitive adhesive optical film according to claim 1, wherein:   The pressure-sensitive adhesive mold according to claim 1, comprising about 0.001 to 20 parts by weight of a crosslinking agent (solid content) with respect to 100 parts by weight of the acrylic polymer (solid content). Optical film.   The crosslinking agent contains an isocyanate crosslinking agent, and the content of the isocyanate crosslinking agent is 0.001 to 2.5 parts by weight with respect to 100 parts by weight of an acrylic polymer (solid content). The pressure-sensitive adhesive optical film according to claim 1.   The crosslinking agent contains a peroxide crosslinking agent, and the content of the peroxide crosslinking agent is 0.02 to 2 parts by weight with respect to 100 parts by weight of the acrylic polymer (solid content). The pressure-sensitive adhesive optical film according to claim 1, wherein: An image display device using at least one adhesive optical film according to claim 1.

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