JP4367704B2 - Antistatic adhesive optical film and image display device - Google Patents

Description

  The present invention relates to an antistatic pressure-sensitive adhesive optical film in which an antistatic layer is laminated on at least one surface of an optical film, and an adhesive layer is further laminated on the antistatic layer. 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 antistatic 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 a liquid crystal display or the like, it is indispensable to dispose polarizing elements on both sides of a liquid crystal cell because of its image forming method, and generally a polarizing plate is attached. 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.

  These optical films are usually bonded with a surface protective film on the surface of the optical film so that the surface of the optical film is not scratched or soiled in the transportation or manufacturing process until it is delivered to consumers. The surface protective film may be peeled off after being attached to an LCD or the like, or the same or another surface protective film may be attached again after being peeled once. And when peeling off this surface protection film, static electricity generate | occur | produced and there existed a problem that circuits, such as an LCD panel, were destroyed by this static electricity. There is also a problem in that the array elements inside the LCD panel are affected, which further affects the alignment of the liquid crystal and induces defects. The surface protection film is not only peeled off, but the same problem occurs due to the friction between the optical films depending on the manufacturing process and the usage method of consumers. In order to solve the above problem, it has been proposed to impart antistatic properties to an optical film such as a polarizing plate. For example, an optical film with an antistatic layer provided with an antistatic layer on the surface of the optical film, and a transparent conductive layer provided on one side or both sides of the optical film are disclosed.

  On the other hand, when sticking an optical film to 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.

  When the adhesive optical film is used, the adhesive optical film is cut to the size of the display and mounted on the liquid crystal panel. The field of use of LCD panels in recent years is not limited to PC displays, but is wide-ranging, such as mobile displays such as LCD TVs and mobile phones, and car parts such as car navigation and instrument panels. ing.

  It has also been proposed to impart antistatic properties to the adhesive optical film. Since an optical film such as a polarizing plate is soluble in an organic solvent and inferior in organic solvent resistance, the antistatic layer applied on the optical film is preferably an aqueous system. However, when high hydrophilic ions are included in order to improve water dispersibility, the water resistance of the coating film is very poor, and the characteristic deterioration is particularly remarkable in a hot water immersion test.

As a method for increasing water resistance, a technique of blending an alkoxysilane having an epoxy group is disclosed (Patent Document 1). However, no effect can be expected for improving hot water resistance.
JP 2002-60736 A

  The present invention is an antistatic pressure-sensitive adhesive optical film in which an antistatic layer is laminated on at least one surface of an optical film, and an adhesive layer is further laminated on the antistatic layer, which has excellent water resistance and wet heat. An object of the present invention is to provide a product having excellent durability that does not cause problems such as peeling and foaming under the environment. It is another object of the present invention to provide an image display device using the antistatic adhesive optical film.

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

  That is, in the present invention, an antistatic layer is laminated on at least one surface of an optical film, and an adhesive layer is further laminated on the antistatic layer, and the antistatic layer is water-soluble or water-dispersible as a raw material component. The present invention relates to an antistatic pressure-sensitive adhesive optical film comprising 10 to 250 parts by weight of a crosslinking reaction type water-soluble compound with respect to 100 parts by weight of a conductive polymer.

  By interposing an antistatic layer between the optical film and the pressure-sensitive adhesive layer, the antistatic effect is excellent in the antistatic effect, optical properties, adhesive properties, and appearance, and the adhesion between the antistatic layer and the pressure-sensitive adhesive layer is excellent. It becomes an adhesive type optical film.

  Specifically, since the antistatic layer is provided between the optical film and the pressure-sensitive adhesive layer, it has a good antistatic effect and can suppress the generation of static electricity due to peeling of the surface protective film and friction due to friction of the optical film. Damage to the liquid crystal and poor alignment of the liquid crystal can be prevented.

  In particular, in the present invention, 10 to 250 parts by weight of a crosslinking reaction type water-soluble compound (binder component) is used as a raw material component of the antistatic layer with respect to 100 parts by weight of the conductive polymer. By forming a three-dimensional network structure by a crosslinking reaction and curing, an antistatic pressure-sensitive adhesive optical film having improved water resistance and durability can be obtained without impairing optical properties and antistatic effects. When the blending amount of the crosslinking reaction type water-soluble compound is less than 10 parts by weight, the effect of improving water resistance is poor, whereas when it exceeds 250 parts by weight, the antistatic effect is poor.

  The water-soluble or water-dispersible conductive polymer is preferably a polythiophene conductive polymer.

  Moreover, it is preferable that the said crosslinking reaction type water-soluble compound which is a binder component is at least 1 sort (s) chosen from the group which consists of an epoxy resin, a melamine-formalin resin, and a urea-formalin resin.

  Moreover, it is preferable that the said adhesive layer is formed with the acrylic adhesive.

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

  As shown in FIG. 1, the antistatic pressure-sensitive adhesive optical film of the present invention has an antistatic layer 2 and an adhesive layer 3 laminated in this order on one side of an optical film 1. In addition, although the case where the adhesive layer 3 is provided in the single side | surface of the optical film 1 is shown in FIG. 1, you may have the adhesive layer 3 on both surfaces of an optical film. Moreover, you may have the antistatic layer 2 also about the adhesive layer 3 of the other surface.

  The antistatic layer 2 of the antistatic adhesive optical film of the present invention contains a water-soluble or water-dispersible conductive polymer and a crosslinking reaction type water-soluble compound as raw material components.

  As the water-soluble or water-dispersible conductive polymer, a polymer having good optical properties, appearance, antistatic effect and antistatic effect when heated and humidified is used. Examples of such a conductive polymer include polymers such as polyaniline, polythiophene, polypyrrole, and polyquinoxaline. Among these, polyaniline, polythiophene, and the like that are likely to become a water-soluble conductive polymer or a water-dispersible conductive polymer are preferably used. Polythiophene is particularly preferable.

  The water-soluble conductive polymer and the water-dispersible conductive polymer can be prepared as an aqueous solution or an aqueous dispersion for forming the antistatic layer, and the coating solution does not need to use a non-aqueous organic solvent. Therefore, it is possible to suppress the deterioration and deterioration of the optical film substrate due to the organic solvent. In addition, although it is preferable from the point of adhesiveness that an aqueous solution or an aqueous dispersion uses only water as a solvent, it may contain a hydrophilic solvent in addition to water. Examples of the hydrophilic solvent include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n-amyl alcohol, isoamyl alcohol, sec-amyl alcohol, and tert-amyl alcohol. And alcohols such as 1-ethyl-1-propanol, 2-methyl-1-butanol, n-hexanol, and cyclohexanol.

  The water-soluble or water-dispersible polyaniline preferably has a weight average molecular weight in terms of polystyrene of 500,000 or less, more preferably 300,000 or less. The weight average molecular weight of the water-soluble or water-dispersible polythiophene in terms of polystyrene is preferably 400,000 or less, more preferably 300,000 or less. When the weight average molecular weight exceeds the above value, the water solubility or water dispersibility tends to be insufficient. When a coating liquid (aqueous solution or water dispersion) is prepared using such a polymer, the coating The solid content of the polymer remains in the liquid, or it tends to be difficult to form an antistatic layer having a uniform thickness by increasing the viscosity.

  The water solubility of the water-soluble conductive polymer means that the solubility in 100 g of water is 5 g or more. The solubility of the water-soluble conductive polymer in 100 g of water is preferably 20-30 g. A water-dispersible conductive polymer is one in which a conductive polymer such as polyaniline or polythiophene is in the form of fine particles and dispersed in water. The aqueous dispersion has a small liquid viscosity and is easy to apply to a thin film. Excellent layer uniformity. Here, the size of the fine particles is preferably 1 μm or less from the viewpoint of the uniformity of the antistatic layer.

  The water-soluble conductive polymer such as polyaniline or polythiophene or the water-dispersible conductive polymer preferably has a hydrophilic functional group in the molecule. Examples of hydrophilic functional groups include sulfone groups, amino groups, amide groups, imino groups, quaternary ammonium bases, hydroxyl groups, mercapto groups, hydrazino groups, carboxyl groups, sulfate ester groups, phosphate ester groups, or salts thereof. Etc. By having a hydrophilic functional group in the molecule, it becomes easy to dissolve in water or to be easily dispersed in water as fine particles, and the water-soluble conductive polymer or water-dispersible conductive polymer can be easily prepared.

  Examples of commercially available water-soluble conductive polymers include polyaniline sulfonic acid (manufactured by Mitsubishi Rayon Co., Ltd., weight average molecular weight of 150,000 in terms of polystyrene). Examples of commercially available water-dispersible conductive polymers include polythiophene-based conductive polymers (manufactured by Nagase Chemtech, Denatron series).

  The crosslinking reaction type water-soluble compound as a binder component is a monomer, oligomer, or polymer that is soluble in water before the crosslinking reaction, and forms a three-dimensional network structure after the crosslinking reaction and becomes insoluble in water. Any compound may be used, and examples thereof include a two-component reactive water-soluble epoxy resin, a melamine-formalin resin, and a urea-formalin resin. These may be used alone or in combination of two or more.

  A two-component reactive water-soluble epoxy resin is composed of a water-soluble polyfunctional epoxy resin and a water-soluble curing agent as main components, and an addition type cross-linking reaction occurs by mixing both, resulting in a three-dimensional polymer network structure. Is formed. Examples of water-soluble polyfunctional epoxy resins include aliphatic groups such as triglycidyl isocyanurate, sorbitol polyglycidyl ether, (poly) glycerol polyglycidyl ether, (poly) ethylene glycol diglycidyl ether, and (poly) propylene glycol diglycidyl ether. And alicyclic glycidyl ethers such as glycidyl ether and sorbitan polyglycidyl ether. On the other hand, examples of water-soluble curing agents include aliphatic polyamines such as diethylenetriamine, triethylenetetramine, and polyamideamine, imidazoles such as 2-methylimidazole and 2-ethyl-4-methylimidazole, and benzyldimethylamine. And tertiary amines such as methyl hymic acid anhydride, acid anhydrides such as phthalic anhydride, and Lewis acids such as boron trifluoride.

  The urea-formalin resin or melamine-formalin resin is obtained by subjecting an initial prepolymer obtained by addition reaction of urea and formaldehyde or melamine and formaldehyde to a dehydration condensation reaction. The initial prepolymer may be modified with phenols or benzoguanamine. Examples of commercially available products of the initial prepolymer include the Euramin series (manufactured by Mitsui Chemicals), the Nicarac series (Sanwa Chemical Co., Ltd.), and the like.

  The compounding quantity of a crosslinking reaction type water-soluble compound is 10-250 weight part with respect to 100 weight part of conductive polymers, More preferably, it is 30-200 weight part.

  As the material for forming the antistatic layer, other binder components may be used in combination for the purpose of improving the film forming property of the antistatic agent and the adhesion to the optical film. It is preferable to use a water-soluble or water-dispersible binder component. Examples of other binder components include polyurethane resins, polyester resins, acrylic resins, polyether resins, cellulose resins, polyvinyl alcohol resins, polyvinyl pyrrolidone, polystyrene resins, polyethylene glycol, pentaerythritol, and the like. It is done. Particularly preferred are polyurethane resins, polyester resins and acrylic resins. These other binder components may be used alone or in combination of two or more as appropriate. Although the usage-amount of another binder component is based also on the kind of conductive polymer, it is 5-100 weight part normally with respect to 100 weight part of conductive polymers, Preferably it is 10-50 weight part.

The surface resistance value of the antistatic layer is preferably 1 × 10 ¹² Ω / □ or less, more preferably 1 × 10 ¹¹ Ω / □ or less. If the surface resistance value exceeds 1 × 10 ¹² Ω / □, the antistatic function is not sufficient, and static electricity is generated and charged due to peeling of the surface protective film or friction of the optical film, which destroys the circuit of the liquid crystal cell. And may cause alignment failure of the liquid crystal.

  The pressure-sensitive adhesive that forms the pressure-sensitive adhesive layer 3 of the antistatic pressure-sensitive adhesive optical film of the present invention is not particularly limited, and examples thereof include acrylic polymers, silicone polymers, polyesters, polyurethanes, polyamides, polyethers, fluorine-based rubbers, and rubbers. A polymer having a base polymer as a base polymer can be appropriately selected and used. In particular, those excellent in optical transparency, exhibiting appropriate wettability, cohesiveness, and adhesive pressure-sensitive adhesive properties and excellent in weather resistance, heat resistance, etc. are preferably used. An acrylic pressure-sensitive adhesive is preferably used as one exhibiting such characteristics.

  The acrylic pressure-sensitive adhesive has an acrylic polymer having a main skeleton of an alkyl (meth) acrylate monomer unit as a base polymer. (Meth) acrylate refers to acrylate and / or methacrylate, and (meth) of the present invention has the same meaning. The average carbon number of the alkyl group of the alkyl (meth) acrylate constituting the main skeleton of the acrylic polymer is about 1 to 12, and specific examples of the alkyl (meth) acrylate include methyl (meth) acrylate, ethyl (Meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate and the like can be exemplified, and these can be used alone or in combination. Among these, alkyl (meth) acrylates having 1 to 9 carbon atoms in the alkyl group are preferable.

  In the acrylic polymer, one or more kinds of various monomers are 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 and other (meth) acrylic acid alkylaminoalkyl monomers; (meth) acrylic (Meth) acrylic acid alkoxyalkyl monomers such as methoxyethyl acid and ethoxyethyl (meth) acrylate; N- (meth) acryloyloxymethylenesuccinimide, N- (meth) acryloyl-6-oxyhexamethylenesuccinimide, N- ( (Meta) acryloyl- - oxy octamethylene succinimide, also including succinimide-based monomers such as N- acryloyl morpholine and the like as a monomer Examples of the reforming purposes.

  Further, 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 carboxylic acid amide , Vinyl monomers such as styrene, α-methylstyrene, N-vinylcaprolactam; cyanoacrylate monomers such as acrylonitrile and methacrylonitrile; epoxy group-containing acrylic monomers such as glycidyl (meth) acrylate; (meth) acrylic Polyethylene glycol acid, polypropylene glycol (meth) acrylate, methoxyethylene glycol (meth) acrylate, methoxypolypropylene (meth) acrylate Glycol acrylic ester monomers such as recall; (meth) acrylic acid tetrahydrofurfuryl, fluorine (meth) acrylate, silicone (meth) acrylate and acrylic acid ester monomers such as 2-methoxyethyl acrylate, etc. may also be used.

  Among these, carboxyl group-containing monomers such as acrylic acid are preferably used from the viewpoints of adhesion to liquid crystal cells and adhesion durability for optical film applications.

  Although the ratio of the copolymerization monomer in the acrylic polymer is not particularly limited, it is preferably about 0.1 to 10% in weight ratio.

  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.

  Examples of rubber-based adhesive base polymers include natural rubber, isoprene-based rubber, styrene-butadiene-based rubber, recycled rubber, polyisobutylene-based rubber, styrene-isoprene-styrene-based rubber, and styrene-butadiene-styrene-based rubber. Etc. Examples of the base polymer of the silicone-based pressure-sensitive adhesive include dimethylpolysiloxane and diphenylpolysiloxane, and those base polymers into which a functional group such as a carboxyl group is introduced can also be used.

  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, and an imine crosslinking agent. As the organic crosslinking agent, an isocyanate crosslinking agent is preferable. 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 bonded or coordinated include an oxygen atom, and examples of the organic compound include an alkyl ester, an alcohol compound, a carboxylic acid compound, an ether compound, and a ketone compound.

  The blending ratio of the base polymer such as an acrylic polymer and the crosslinking agent is not particularly limited, but usually, the crosslinking agent (solid content) is preferably about 0.01 to 10 parts by weight with respect to 100 parts by weight of the base polymer (solid content). Furthermore, about 0.1-5 weight part is preferable.

  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 optical film 1 used for the antistatic 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. For example, the optical film includes 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 by, for example, dying 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. For example, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as diacetyl cellulose and triacetyl cellulose, acrylic polymers such as polymethyl methacrylate, styrene such as polystyrene and acrylonitrile / styrene copolymer (AS resin) -Based polymer, polycarbonate-based polymer and the like. In addition, polyethylene, polypropylene, polyolefins having a cyclo or norbornene structure, polyolefin polymers such as ethylene / propylene copolymers, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamide, imide polymers, sulfone polymers , Polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, arylate polymer, polyoxymethylene polymer, epoxy polymer, or the above Polymer blends and the like are also examples of polymers that form the transparent protective film. 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.

  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.

  Although the thickness of a 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 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 protective film having a direction retardation of −90 nm to +75 nm is preferably used. By using a film having a thickness direction retardation value (Rth) of −90 nm to +75 nm, coloring (optical coloring) of the polarizing plate caused by the 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.

  As the protective film, a cellulose polymer such as triacetyl cellulose is preferable from the viewpoints of polarization characteristics and durability. A triacetyl cellulose film is particularly preferable. In addition, when providing a protective film on both sides of a polarizer, the 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 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 screen.

  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 through 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 the alignment surface such as those obtained by rubbing the surface of a thin film such as polyimide or polyvinyl alcohol formed on a glass plate, or by obliquely depositing 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 those for the purpose of compensating for coloration, vision, etc. due to birefringence of various wavelength plates and liquid crystal layers. 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 directly incident on the polarizing plate with the polarization axis aligned, 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 antistatic pressure-sensitive adhesive optical film will be described.

  On the optical film 1 described above, the antistatic layer 2 is formed from a cured product of a coating solution containing a water-soluble or water-dispersible conductive polymer and a crosslinking reaction type water-soluble compound in the above-mentioned blending ratio. The solid concentration of the coating solution is preferably adjusted to about 0.5 to 5% by weight. First, the coating solution is applied onto the optical film 1 using a coating method such as 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. The antistatic layer is formed by drying and further curing or crosslinking the crosslinking reaction type water-soluble compound by heating or light irradiation. In addition, by controlling the temperature, the crosslinking reaction type water-soluble compound may be crosslinked and cured at the time of drying. Moreover, the adhesiveness of an antistatic layer and an adhesive layer can be improved by partially bridge | crosslinking a crosslinking reaction type water-soluble compound, and completing a crosslinking reaction at the time of subsequent formation of an adhesive layer.

  The thickness of the antistatic layer is preferably 5 to 1000 nm. The thickness of the antistatic layer is usually 5000 nm or less from the viewpoint of deterioration of optical characteristics. However, when the antistatic layer is thick, the antistatic layer tends to break down due to insufficient strength of the antistatic layer, and sufficient adhesion is achieved. Sexuality may not be obtained. The thickness of the antistatic agent is preferably 500 nm or less, more preferably 300 nm or less, and further preferably 200 nm or less. In order to ensure adhesion and suppress peeling charge, the thickness is preferably 5 nm or more, and more preferably 10 nm or more. On the other hand, the peeling charge effect is preferably greater in the thickness of the antistatic layer, but is less than or equal to 200 nm. From this point, it is preferably 5 to 500 nm, more preferably 10 to 300 nm, and further preferably 10 to 200 nm.

  In forming the antistatic layer 2, the optical film 1 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. The activation treatment is effective when an aqueous solution containing a water-soluble conductive polymer is used as an antistatic agent, and repelling when applying the aqueous solution can be suppressed. The activation treatment is effective particularly when the optical film 1 is a polyolefin resin or a norbornene resin.

  The pressure-sensitive adhesive layer 3 is formed by laminating on the antistatic layer 2. The forming method is not particularly limited, and examples thereof include a method of applying a pressure-sensitive adhesive solution to the antistatic layer and drying, a method of transferring with a release sheet provided with a pressure-sensitive adhesive layer, and the like. Although the thickness of an adhesive layer is not specifically limited, It is preferable to set it as about 10-40 micrometers.

  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 3, 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, in each layer such as an optical film and an adhesive layer of the antistatic adhesive optical film of the present invention, for example, a salicylic acid ester compound, a benzophenol compound, a benzotriazole compound, a cyanoacrylate compound, a nickel complex compound It is also possible to use one having a UV-absorbing ability by a method such as a method of treating with a UV absorber.

  The adhesion between the antistatic layer 2 and the pressure-sensitive adhesive layer 3 is preferably 10 N / 25 mm or more, more preferably 15 N / 25 mm or more at a peeling angle of 180 ° and a peeling speed of 300 mm / min. When the adhesive force is less than 10 N / 25 mm, there is a possibility that adhesive residue may be generated when the optical film is peeled from the liquid crystal panel, or peeling may occur in a heated / humidified heat environment.

  The antistatic 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 antistatic adhesive optical film, and an illumination system as necessary, and incorporating a drive circuit. There is no particular limitation except that the optical film according to the present invention is used, and the conventional method can be applied. 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 antistatic pressure-sensitive adhesive optical film is disposed on one side or both sides of a liquid crystal cell, or a backlight system 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 diffusion plate, an antiglare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffusion plate, a backlight, 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 formed by 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.

(Preparation of polarizing plate)
A polyvinyl alcohol film having a thickness of 80 μm was stretched 5 times in an iodine aqueous solution at 40 ° C. and then dried at 50 ° C. for 4 minutes to obtain a polarizer. A triacetyl cellulose film was bonded to both sides of this polarizer using a polyvinyl alcohol-based pressure-sensitive adhesive to obtain a polarizing plate.

Example 1
(Formation of antistatic layer)
1) 100 parts of an aqueous dispersion (manufactured by Bayer AG, BaytronP, solid content 4%) containing poly (3,4-ethylenedioxythiophene) and polystyrenesulfonic acid as the conductive polymer, and 2) sorbitol polyglycidyl as the main agent A crosslinking reaction type comprising 4 parts of an ether-based epoxy resin (manufactured by Nagase ChemteX Corporation, Denacol EX-614B) and 0.2 part of 2-ethyl-4-methylimidazole (manufactured by Shikoku Kasei Co., Ltd., 2E4MZ) as a curing agent. A water-soluble compound was mixed, and the mixture was diluted 5-fold with a 2-isopropanol aqueous solution (2-isopropanol: 80%) to prepare a coating solution. Using a wire bar (# 8), the coating solution is applied to one side of the polarizing plate so that the thickness after drying is 150 nm, and heated at 40 ° C. for 3 minutes to dry and crosslink the reaction type water-soluble compound. Was crosslinked and cured to form an antistatic layer.

(Formation of adhesive layer)
As a base polymer, 100 parts of butyl acrylate, 5 parts of acrylic acid, and 0.1 part of 2-hydroxyethyl acrylate are dissolved in 300 parts of ethyl acetate and reacted at about 60 ° C. for 6 hours with stirring to give a weight average molecular weight of 2 million. A solution (solid content 24%) containing an acrylic polymer was prepared. Coronate L manufactured by Nippon Polyurethane Co., Ltd., which is an isocyanate-based polyfunctional compound, is added to the acrylic polymer solution in an amount of 3.2 parts with respect to 100 parts of the polymer solid content, and 0.6 parts of additive (Shin-Etsu Silicone Co., Ltd., KBM-403). And ethyl acetate (solvent) were added to prepare a pressure-sensitive adhesive solution (solid content 11%). The adhesive solution is applied by a reverse roll coating method on a release sheet (Mitsubishi Chemical Polyester, Diafoil MRF38, polyethylene terephthalate base material) so that the thickness after drying is 25 μm, and further on A release sheet was applied and dried in a hot air circulation oven to form an adhesive layer.

(Preparation of antistatic adhesive optical film)
On the antistatic layer of the antistatic polarizing plate, a release sheet on which an adhesive layer was formed was bonded, and this was aged at room temperature for 1 week to prepare an antistatic adhesive polarizing plate.

Example 2
In the formation of the antistatic layer of Example 1, the sorbitol polyglycidyl ether type epoxy resin was changed from 4 parts to 1.2 parts, and 2-ethyl-4-methylimidazole was changed from 0.2 parts to 0.1 parts. An antistatic pressure-sensitive adhesive polarizing plate was produced in the same manner as in Example 1 except for the change.

Example 3
Example 1 except that 8 parts of melamine-formaldehyde prepolymer (Mitsui Chemicals Co., Ltd., Eulamin P-6300, solid content 50%) was used as the crosslinking reaction type water-soluble compound in the formation of the antistatic layer of Example 1. An antistatic adhesive polarizing plate was prepared by the same method as described above.

Comparative Example 1
In the formation of the antistatic layer of Example 1, an antistatic pressure-sensitive adhesive polarizing plate was produced in the same manner as in Example 1 except that the crosslinking reaction type water-soluble compound was not used.

Comparative Example 2
In the formation of the antistatic layer of Example 1, 16 parts of a non-crosslinkable polyester resin aqueous dispersion (manufactured by Nagase Chemtex Co., Ltd., Kabsen ES-210, solid content 25%) was used instead of the crosslinking reaction type water-soluble compound. An antistatic pressure-sensitive adhesive polarizing plate was produced in the same manner as in Example 1 except that it was used.

Comparative Example 3
In the formation of the antistatic layer of Example 1, the sorbitol polyglycidyl ether type epoxy resin was changed from 4 parts to 0.2 parts, and 2-ethyl-4-methylimidazole was changed from 0.2 parts to 0.02 parts. An antistatic pressure-sensitive adhesive polarizing plate was produced in the same manner as in Example 1 except for the change.

Comparative Example 4
In the formation of the antistatic layer of Example 1, the sorbitol polyglycidyl ether type epoxy resin was changed from 4 parts to 12 parts, and 2-ethyl-4-methylimidazole was changed from 0.2 parts to 0.5 parts. Except for the above, an antistatic pressure-sensitive adhesive polarizing plate was produced in the same manner as in Example 1.

  The following evaluation was performed about the antistatic adhesive optical film obtained by the Example and the comparative example. The evaluation results are shown in Table 1.

[Adhesion]
The produced antistatic adhesive optical film was cut into a width of 25 mm and a length of 50 mm. After the adhesive layer surface and the 50 μm-thick polyethylene terephthalate film surface were bonded so that the vapor deposition surface of the vapor deposition film on which indium-tin oxide was vapor-deposited was in contact, the environment was kept at 23 ° C./60% RH for 20 minutes or more. Left alone. Then, after peeling the edge part of a polyethylene terephthalate film by hand and confirming that the adhesive has adhered to the polyethylene terephthalate film side, using a tensile tester (Shimadzu Corporation, Autograph AG-1) The adhesion (N / 25 mm) between the antistatic layer and the pressure-sensitive adhesive layer was measured in a room temperature atmosphere (25 ° C.) at 180 ° peeling and a tensile speed of 300 mm / min. Such adhesion (N / 25 mm) is preferably 15 N / 25 mm or more.

(Water resistance evaluation)
(Adhesion)
The produced antistatic adhesive optical film was cut into a width of 25 mm and a length of 50 mm. The pressure-sensitive adhesive layer surface and the 50 μm thick polyethylene terephthalate film surface were bonded so that the vapor deposition surface of the vapor deposition film on which indium-tin oxide was vapor-deposited, and then left in an environment of 60 ° C./90% RH for 24 hours. did. Thereafter, adhesion (N / 25 mm) was measured by the same method as in the above test. Such adhesion (N / 25 mm) is preferably 15 N / 25 mm or more.

(Warm water immersion)
The prepared antistatic adhesive optical film was cut into a size of 100 mm × 100 mm to obtain a sample. The pressure-sensitive adhesive layer of the sample was attached to a glass plate, immersed in warm water at 40 ° C. for 10 hours, then visually observed and evaluated according to the following criteria.
○: There is no defect such as peeling or foaming on the optical film.
X: Peeling is observed between the antistatic layer and the pressure-sensitive adhesive layer.

[Antistatic effect]
The produced antistatic pressure-sensitive adhesive optical film was cut into a size of 100 mm × 100 mm and attached to a liquid crystal panel. This panel was placed on a backlight having a luminance of 10,000 cd, and 5 kv of static electricity was generated using ESD (SANKI, ESD-8012A) which is a static electricity generating device, thereby causing liquid crystal alignment disorder. The display failure recovery time (seconds) due to the alignment failure was measured using an instantaneous multiphotometric detector (MCPD-3000, manufactured by Otsuka Electronics Co., Ltd.).

It is an example of sectional drawing of the antistatic adhesive optical film of this invention.

Explanation of symbols

1 Optical film 2 Antistatic layer 3 Adhesive layer

Claims (5)

  An antistatic layer is laminated on at least one surface of the optical film, and a pressure-sensitive adhesive layer is further laminated on the antistatic layer. An antistatic pressure-sensitive adhesive optical film comprising 10 to 250 parts by weight of a crosslinking reaction type water-soluble compound with respect to parts.   The antistatic pressure-sensitive adhesive optical film according to claim 1, wherein the water-soluble or water-dispersible conductive polymer is a polythiophene-based conductive polymer.   The antistatic pressure-sensitive adhesive optical film according to claim 1 or 2, wherein the crosslinking reaction type water-soluble compound is at least one selected from the group consisting of an epoxy resin, a melamine-formalin resin, and a urea-formalin resin.   The antistatic pressure-sensitive adhesive optical film according to claim 1, wherein the pressure-sensitive adhesive layer is formed of an acrylic pressure-sensitive adhesive. An image display device using at least one antistatic pressure-sensitive adhesive optical film according to claim 1.

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