WO2006003827A1 - Optical film having pressure-sensitive adhesive attached thereto and image display device - Google Patents

Abstract

An optical film having a pressure-sensitive adhesive layer on at least one surface thereof, characterized in that the pressure-sensitive adhesive layer has a Tg of -35°C or lower. The above optical film with a pressure-sensitive adhesive exhibits such durability that the curvature thereof can be inhibited even when exposed to a low temperature circumstance of room temperature or lower.

Description

 Specification

 Optical film with adhesive and image display device

 Technical field

 [0001] The present invention relates to an optical film with an adhesive having an adhesive layer on at least one surface of an optical film. Furthermore, the present invention relates to an image display device such as a liquid crystal display device, an organic EL display device, or a PDP using the optical film with an adhesive. The optical film with a pressure-sensitive adhesive of the present invention is suitable for a film containing a stretched film as an optical film, for example, a polarizing plate, a phase difference plate, an optical compensation film, a brightness enhancement film, and those in which these are laminated. Etc.

 Background art

 A liquid crystal display device is used for a clock, a television, a monitor, etc., as well as a calculator.

 Since these products are used under various conditions in various environments, various durability is required. Various optical films such as a polarizing plate and a retardation plate are used for the liquid crystal display device. These optical films are used as an optical film with an adhesive in order to bond them to various optical members. Therefore, durability is also required for optical films with adhesives.

 [0003] In order to improve the durability of an optical film with an adhesive, various studies have been made on the adhesive layer. For example, there are methods such as increasing the molecular weight of the base polymer used for the pressure-sensitive adhesive, copolymerizing a high Tg monomer with the base polymer, and increasing the degree of crosslinking. As the above-mentioned pressure-sensitive adhesive, an acrylic pressure-sensitive adhesive is used for its excellent adhesion, transparency and the like (see Patent Document 1). However, if the optical film with adhesive is made durable by these methods, the residual stress of the adhesive layer becomes stronger. As a result, this acts on the optical film, causing the optical film to warp, causing a serious problem if the display quality of the liquid crystal display device is impaired.

 Patent Document 1: Japanese Patent Laid-Open No. 11-52349

 Disclosure of the invention

Problems to be solved by the invention [0004] Further, with respect to the durability of the optical film with an adhesive, it has been mainly carried out to improve the durability under high temperature and high temperature / high temperature conditions. In recent years, the use of liquid crystal display devices such as televisions and in-cars has begun to increase. As a result, optical films with adhesives are required to have durability not only at high temperatures and high temperatures and high humidity but also at low temperatures such as 30 ° C. However, conventional optical films with pressure-sensitive adhesives using acrylic pressure-sensitive adhesives (for example, polarizing plates with pressure-sensitive adhesive layers) have satisfactory durability under high temperature and high temperature and high temperature conditions, even at room temperature (23 ° C). ) The optical film with pressure-sensitive adhesive that is not sufficiently durable under the following low temperature conditions caused a large warp when it was exposed to low temperature conditions while being adhered to a glass plate or the like.

 [0005] An object of the present invention is to provide an optical film with a pressure-sensitive adhesive that can suppress warping of the optical film even when placed in a low temperature environment of room temperature or lower.

 [0006] Another object of the present invention is to provide an image display device using the optical film with an adhesive.

 Means for solving the problem

[0007] As a result of intensive studies to solve the above problems, the present inventors have found that the above object can be achieved by the following optical film with an adhesive, etc., and have completed the present invention.

That is, the present invention relates to an optical film with an adhesive having an adhesive layer on at least one side of the optical film,

 The present invention relates to an optical film with an adhesive, wherein the adhesive layer has a Tg of −35 ° C. or lower.

 [0009] Generally, the pressure-sensitive adhesive has a Tg of room temperature or lower. The temperature region near Tg is a transition region between the glassy state and the rubbery state. When the glassy state is exceeded beyond Tg, the elasticity of the adhesive increases rapidly, resulting in an optical film. Even small dimensional changes such as heat shrinkage cannot be sufficiently followed, resulting in large warpage.

[0010] On the other hand, warping in a low temperature region differs from warping in a heating or humidified state that is usually tested, and in optical films (especially stretched films), a strong warp occurs in the direction of 90 ° with the stretching axis and returns to room temperature And there is a characteristic that the warp disappears and it returns to the original. This is an optical film, especially a polarizing plate This is because the internal force that the coefficient of thermal expansion in the direction of the stretching axis and the 90 ° direction is larger than that in the direction of the stretching axis is also due to the larger force in the direction of the stretching axis and 90 °. The phenomenon that the warp disappears when the temperature returns to room temperature indicates that the warp in the low temperature region largely depends only on the thermal stress of the optical film.

 [0011] Therefore, in the present invention, by using a pressure-sensitive adhesive layer having a Tg of not more than 35 ° C, warpage caused by stress accompanying dimensional change of a member such as an optical film in a low temperature region is suppressed. . Thereby, it is possible to provide an optical film with a pressure-sensitive adhesive having excellent durability not only in a high temperature region but also in a low temperature region. The Tg of the pressure-sensitive adhesive layer is preferably −40 ° C. or lower, more preferably −50 ° C. or lower. Note that if Tg is too low, durability under high temperature conditions decreases, so that it is preferably −120 ° C. or higher, more preferably 100 ° C. or higher.

 [0012] The optical film with pressure-sensitive adhesive has an internal force (F) caused by thermal stress of the optical film,

 F = a-ΔΤ-Ε -1-h

 (Where α is the coefficient of thermal expansion at -60 to 23 ° C, ΔΤ is the temperature difference when 23 ° C is the reference, E is the elastic modulus, 1 is the width, and h is the thickness). In case,

 This is effective for an optical film having a stretched film and an internal force (F) generated in the 90 ° direction with respect to the stretching axis of the stretched film at 0 ° C is 50 N or more.

[0013] As the optical film having the internal force (F) force of 50 N or more, the optical film with a pressure-sensitive adhesive of the present invention, which easily warps at a low temperature, can be suitably applied. The optical film with pressure-sensitive adhesive of the present invention is suitable when the internal force (F) of the optical film has 70N or more, further 100N or more.

 [0014] The optical film with pressure-sensitive adhesive can be suitably applied to an optical film containing a polarizing plate and Z or a retardation plate. A film using a stretched film as a constituent element of a polarizing plate and Z or a retardation plate can be suitably applied to the optical film with an adhesive of the present invention as soon as warpage occurs at a low temperature.

 [0015] The present invention also relates to an image display device using at least one optical film with an adhesive.

BEST MODE FOR CARRYING OUT THE INVENTION [0016] The optical film with an adhesive of the present invention has an adhesive layer on one side of the optical film. The adhesive layer is formed of a material having a low Tg of −35 ° C. or lower, and an appropriate pressure-sensitive adhesive can be used for forming the pressure-sensitive adhesive layer, and the type thereof is not particularly limited. Adhesives include rubber-based adhesives, acrylic-based adhesives, silicone-based adhesives, urethane-based adhesives, buralkyl ether-based adhesives, polybulal alcohol-based adhesives, polybulphine-lididone-based adhesives, and polyacrylamide-based adhesives. Agents, cellulosic adhesives, etc.

Among these pressure-sensitive adhesives, those having excellent optical transparency, suitable wettability, cohesiveness, and adhesive properties, and excellent weather resistance and heat resistance are preferably used. An acrylic pressure-sensitive adhesive is preferably used as a material exhibiting such characteristics.

 [0018] The acrylic pressure-sensitive adhesive has an acrylic polymer mainly composed of a monomer unit of (meth) acrylic acid alkyl ester as a base polymer. In addition, (meth) acrylic acid alkyl ester means acrylic acid alkyl ester and Z or 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 2 to 18 carbon atoms. For example, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethyl hexyl (meth) acrylate, isooctyl (meth) acrylate, isonoyl (meth) acrylate, isomristyl (meth) acrylate And lauryl (meth) acrylate. As the (meth) acrylic acid alkyl ester, an acrylic acid alkyl ester having a branched alkyl group is particularly suitable. For example, 2-ethylhexyl acrylate, isooctyl acrylate, isononyl acrylate, isomyristyl acrylate, and the like are preferably used.

[0019] One or more kinds of copolymerization monomers can be introduced into the acrylic polymer by copolymerization for the purpose of improving adhesiveness and heat resistance. Specific examples of such copolymerization monomers include, for example, (meth) acrylic acid 2-hydroxyethyl, (meth) acrylic acid 2-hydroxypropyl, (meth) acrylic acid 4-hydroxybutyl, and (meth) acrylic acid. 6-hydroxyhexyl, (meth) acrylic acid 8-hydroxyoctyl, (meth) acrylic acid 10-hydroxydecyl, (meth) acrylic acid 12-hydroxylauryl and (4-hydroxymethylcyclohexyl) monomethyl Hydroxyl group-containing monomers such as ruatrate; Carboxyl groups such as (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid Containing monomer; Maleic anhydride, Itaconic anhydride and other acid anhydride group-containing monomer; Acrylic acid power product with prolatathone; Styrene sulfonic acid gallic sulfonic acid, 2- (meth) acrylamide-2-methylpropane sulfonic acid Sulfonic acid group-containing monomers such as, (meth) acrylamide propane sulfonic acid, sulfopropyl (meth) acrylate, (meth) ateroyloxynaphthalene sulfonic acid; 2-phosphoric acid group-containing monomers such as hydroxychetyl attalyloyl phosphate Etc.

 [0020] (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. (Meth) acrylic acid aminoethyl, (meth) acrylic acid and N dimethylaminoethyl, (meth) acrylic acid t-butylaminoethyl and other (meth) acrylic acid alkylaminoalkyl monomers; (meth) acrylic acid methoxy ester And (meth) acrylic acid alkoxyalkyl monomers such as (meth) acrylic acid ethoxyethyl; N— (meth) acryloyloxymethylene succinimide N— (meth) acryloyl 1-6-oxyhexamethylene succinimide, N— ( Meta) Atari Roy Roux 8-Oxiotame Examples of monomers include succinimide monomers such as ethylene succinimide and N-atallyloylmorpholine.

[0021] Further, as modifying monomers, butyl acetate, butyl propionate, N-butyl pyrrolidone, methyl vinyl pyrrolidone, vinyl pyridine, vinyl piperidone, vinyl pyrimidine, vinyl piperazine, bulpyrazine, bur pyrrole, bur imidazole, buroxazol, Bull morpholine, N-vinyl carboxylic acid amides, styrene, α-methyl styrene, ビ ュ Bull monomers such as buler force prolatatum; Cyanacrylate monomers such as acrylonitrile and methatalonitrile; Epoxy groups such as glycidyl (meth) acrylate Containing acrylic monomer; polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, methoxyethylene glycol (meth) acrylate, (meth) acrylic acid Glycol acrylic ester monomers such as methoxypolypropylene glycol; (meth) tetrahydrofurfuryl acrylate, fluorine (meth) acrylate, silicone (meth) ate relay It is also possible to use acrylic acid ester monomers such as 2-methoxyethyl acrylate.

 Among these, a hydroxyl group-containing monomer and a carboxyl 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.

[0023] The proportion of the copolymerization monomer in the acrylic polymer is not particularly limited, but is preferably about 0 to 30%, more preferably about 0 to 15% in the weight ratio of all the constituent monomers.

 [0024] 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 Balta polymerization method, a solution polymerization method, or a suspension polymerization method can be appropriately selected. As the radical polymerization initiator, various known ones such as azo and peroxide can be used. The reaction temperature is usually about 50-80 ° C, and the reaction time is 1-8 hours. Among the above production methods, ethyl acetate, toluene and the like are generally used as the solvent for the acrylic polymer for which the solution polymerization method is preferred. The solution concentration is usually about 20 to 80% by weight.

 [0025] Examples of the base polymer of the rubber-based adhesive include natural rubber, isoprene-based rubber, styrene-butadiene-based rubber, recycled rubber, polyisobutylene-based rubber, styrene-soprene-styrene-based rubber, styrene-butadiene-based rubber. Examples thereof include styrene rubber. Examples of the base polymer for the silicone-based pressure-sensitive adhesive include dimethylpolysiloxane and diphenylpolysiloxane. These base polymers can also be used in which functional groups such as carboxyl groups are introduced.

[0026] The pressure-sensitive adhesive is preferably a pressure-sensitive adhesive composition containing a crosslinking agent. Examples of the polyfunctional compound that can be added to 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. A polyfunctional metal chelate is a polyvalent metal covalently bonded to an organic compound or It is a coordinate bond. Multivalent metal atoms include Al, Cr, Zr, Co, Cu, Fe, Ni, V, Zn, In, Ca, Mg, Mn, Y, Ce, Sr, Ba, Mo, La, Sn, Ti, etc. can give. Examples of the atoms in the organic compound to be bonded or coordinated include an oxygen atom, and examples of the organic compound include alkyl esters, alcohol compounds, carboxylic acid compounds, ether compounds, and ketone compounds.

 [0027] The mixing ratio of the base polymer such as acrylic polymer and the crosslinking agent is not particularly limited! However, usually, about 0.01 to 20 parts by weight of the cross-linking agent (solid content) is preferable with respect to 100 parts by weight of the base polymer (solid content), and more preferably about 0.01 to 15 parts by weight.

 [0028] Sarakuko has a tackifier, plasticizer, glass fiber, glass beads, metal powder, other inorganic powders, and other fillers, pigments, colorants, Fillers, antioxidants, ultraviolet absorbers, silane coupling agents, and the like, and various additives can be appropriately used within the range V and 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.

 [0029] As the additive, a silane coupling agent is suitable, and the silane coupling agent (solid content) is preferably about 0.001 to LO parts by weight with respect to 100 parts by weight of the base polymer (solid content). Further, it is preferable to add about 0.005 to 5 parts by weight. As the silane coupling agent, those known in the past can be used without particular limitation. For example, containing epoxy groups such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropinoletriethoxysilane, 3-glycidoxypropylmethyljetoxysilane, 2- (3,4 epoxycyclohexyl) ethyltrimethylsilane Silane coupling agents, 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) 3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N- (1,3 dimethylbutylidene) propylamine, etc. Amino group-containing silane coupling agents, 3-acryloylpropyltrimethoxysilane, 3-methacryloxypropyl (meth) acrylic group-containing silane coupling agents such as pyrtriethoxysilane, and isocyanates such as 3-isocyanatopropyltriethoxysilane Group-containing silane cup A ring agent can be exemplified.

[0030] As the optical film used for the optical film with pressure-sensitive adhesive 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 particularly limited. Absent. The optical film is preferably applied to a film having a stretched film such as a polarizing plate or a retardation plate.

 [0031] 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 hydrophilic polymer films such as polybulal alcohol films, partially formalized polybulal alcohol films, and ethylene 'butyric acid copolymer copolymer ken-yi films, iodine and dichroism. Examples include uniaxially drawn dichroic substances adsorbed on dyes, and polyylene-oriented films such as polyvinyl alcohol dehydrated products and polyvinyl chloride dehydrochlorinated products. Among these, a polybulol alcohol film and a polarizer having a dichroic substance power such as iodine are preferable. The thickness of these polarizers is not particularly limited, but is generally about 5 to 80 μm.

[0032] A polarizer obtained by uniaxially stretching a polyvinyl alcohol-based film dyed with iodine is prepared by, for example, dyeing polyvinyl alcohol by immersing it in an aqueous solution of iodine and stretching it 3 to 7 times the original length. Can do. If necessary, it can also be immersed in an aqueous solution of potassium iodide or the like which may contain boric acid, zinc sulfate, zinc chloride and the like. Furthermore, if necessary, the polyvinyl alcohol film may be immersed in water and washed before dyeing. By washing the polybulal alcohol-based film with water, it is possible to clean the surface of the polybulal alcohol-based film and the anti-blocking agent, and by swelling the polyvinyl alcohol-based film, unevenness such as uneven dyeing can be achieved. There is also an effect to prevent. The stretching may be performed after dyeing with iodine, may be performed while dyeing, or may be stretched and dyed with strong iodine. The film can be stretched even in an aqueous solution of boric acid or potassium iodide or in a water bath.

[0033] As a material for forming a transparent protective film provided on one 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-based polymers such as polyethylene terephthalate and polyethylene naphthalate, cenorelose-based polymers such as dicetinoresenorelose and triacetinoloselenolose, acrylic polymers such as polymethylmethacrylate, polystyrene and Styrene polymer such as styrene copolymer (AS resin), polycarbonate polymer One is given. In addition, polyethylene, polypropylene, polyolefins having a cyclo or norbornene structure, polyolefin polymers such as ethylene / propylene copolymers, salt-and-bulb polymers, amide polymers such as nylon and aromatic polyamide, imide polymers, Snorephone-based polymer, Polyetherenorenolephone-based polymer, Polyethylene-noreno-ketone-based polymer, Polyphenylene sulfide-based polymer, Vinyl alcohol-based polymer, Vinylidene chloride-based polymer, Vinyl butyral-based polymer, Arylate-based polymer, Polyoxymethylene-based Examples of the polymer that forms the transparent protective film include polymers, epoxy polymers, and blends of the above 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.

 [0034] Also, a polymer film described in JP-A-2001-343529 (WO01Z37007), for example, (A) a thermoplastic resin having a substituted side chain and a Z or non-midamide group, and (B) side Examples thereof include a resin composition containing a thermoplastic resin having a substituted and Z or unsubstituted fullyl and -tolyl group in the chain. A specific example is a film of a resin composition containing an alternating copolymer of isobutylene and N-methylmaleimide and an acrylonitrile / styrene copolymer. As the film, a strong film such as a mixed extruded product of the resin composition can be used.

 [0035] The thickness of the protective film can be determined as appropriate, but is generally about 1 to 500 m from the viewpoints of workability such as strength and handleability, and thin film properties. In particular, 5 to 200 m is preferable.

 [0036] Further, it is preferable that the protective film is as colored as possible. Therefore, Rth = [(n x + ny) / 2-nz]. D (where nx and ny are the main refractive index in the film plane, nz is the refractive index in the film thickness direction, and d is the film thickness). Represents 90ηπ phase difference in the film thickness direction! A protective film of ~ + 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 protective film can be almost eliminated. The thickness direction retardation (Rth) is more preferably from 80 nm to +60 nm, particularly preferably from 70 nm to +45 nm.

[0037] As the protective film, triacetyl cellulose and the like from the viewpoint of polarization characteristics and durability. Cellulosic polymers are preferred. A triacetyl cellulose film is particularly preferable. In the case where protective films are provided on both sides of the polarizer, protective films having the same polymer material strength may be used on the front and back sides, or different protective films having the same polymer material strength 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 water-based adhesives include isocyanate-based adhesives, polyvinyl alcohol-based adhesives, gelatin-based adhesives, vinyl-based latex-based, water-based polyurethane, water-based polyester, and the like.

 [0038] The surface of the transparent protective film to which the polarizer is not bonded may be subjected to a hard coat layer, antireflection treatment, anti-sticking treatment, or treatment for diffusion or anti-glare.

 [0039] The hard coat treatment is performed for the purpose of preventing the surface of the polarizing plate from being scratched. For example, curing with excellent UV hardness curable resin such as acrylic and silicone is excellent in hardness and sliding properties. It can be formed by a method of adding a film to the surface of the transparent protective 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. In addition, the sticking prevention treatment is performed for the purpose of preventing adhesion with an adjacent layer of another member.

[0040] The anti-glare treatment is performed for the purpose of preventing external light from being reflected on the surface of the polarizing plate and obstructing the visual recognition of the light transmitted through the polarizing plate. 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 surface roughening method or a method of blending transparent fine particles. Examples of the fine particles to be included in the formation of the surface fine concavo-convex structure include silica, alumina, titanium dioxide, zirconium oxide, tin oxide, indium oxide, cadmium oxide, and acid oxide having an average particle diameter of 0.5 to 50 μm. Transparent fine particles such as inorganic fine particles that may have conductivity such as antimony and organic fine particles (including beads) that also have crosslinked or uncrosslinked polymer are used. In the case of forming a surface fine concavo-convex structure, the amount of fine particles used is generally about 2 to 50 parts by weight with respect to 100 parts by weight of the transparent resin forming the surface fine concavo-convex structure, and 5 to 25 parts by weight preferable. 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. [0041] The antireflection layer, the anti-sticking layer, the diffusion layer, the antiglare layer, and the like can be provided on the transparent protective film itself, or separately from the transparent protective film as an optical layer. It can also be provided.

 [0042] Further, 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 1Z2 and 1Z4), a visual compensation film, and a brightness enhancement film. And an optical layer that has a problem. These can be used alone as an optical film, or can be laminated on the polarizing plate for practical use and used in one or more layers.

 [0043] In particular, a reflective polarizing plate or a semi-transmissive polarizing plate in which a polarizing plate is further laminated with a reflective plate or a semi-transmissive reflective plate, and an elliptical polarizing plate or a circular 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 the polarizing plate, or a polarizing plate in which a brightness enhancement film is further laminated on the polarizing plate are preferable.

 [0044] The reflective polarizing plate is a polarizing plate provided with a reflective layer, and is used to form a liquid crystal display device of a type that reflects and displays incident light from the viewing side (display side). In addition, there is an advantage that the built-in light source such as a backlight can be omitted and the liquid crystal display device can be thinned easily. The reflective polarizing plate can be formed by an appropriate method such as a method in which a reflective layer having a metal isotropic force is attached to one surface of the polarizing plate via a transparent protective layer or the like, if necessary.

[0045] As a specific example of the reflective polarizing plate, a reflective layer is formed by attaching a foil vapor-deposited film made of a reflective metal such as aluminum on one side of a transparent protective film matted as necessary. Etc. In addition, the transparent protective film may include fine particles having a surface fine uneven structure, and a reflective layer having a fine uneven structure on the surface. The reflective layer having the fine concavo-convex structure described above has the advantage that incident light is diffused by irregular reflection to prevent directivity and glaring appearance, and to suppress unevenness in brightness and darkness. In addition, the protective film containing fine particles has an advantage that incident light and its reflected light are diffused when passing through it and light and darkness can be further suppressed. The reflective layer with a fine concavo-convex structure reflecting the fine concavo-convex structure on the surface of the transparent protective film is used to protect the metal transparently by an appropriate method such as a vacuum deposition method, an ion plating method, or a sputtering method. It can be performed by a method of attaching directly to the surface of the layer.

 [0046] 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 in which a reflecting layer is provided on an appropriate film according to the transparent film. In addition, since the reflective layer usually has a metallic force, the usage state in which the reflective surface is covered with a transparent protective film or a polarizing plate is used to prevent the reflectance from being lowered by oxidation, and thus the long-term initial reflectance. It is more preferable in terms of sustainability and avoiding the separate provision of a protective layer.

 [0047] The transflective polarizing plate can be obtained by using a transflective reflective layer such as a half mirror that reflects and transmits light by the reflective layer. Transflective polarizing plate

Normally, it is provided on the back side of the liquid crystal cell, and when using a liquid crystal display device etc. in a relatively bright atmosphere, it reflects the incident light from the viewing side (display side) and displays an image. Under the atmosphere, it is built in the back side of the transflective polarizing plate and can be used to form liquid crystal display devices that display images using a built-in power source such as a backlight.

. In other words, the transflective polarizing plate can save energy when using a light source such as a knocklight in a bright atmosphere, and can be used with a built-in power supply even in a relatively low atmosphere. It is useful for the formation of

 [0048] 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 into elliptically or circularly polarized light, changing elliptically or circularly polarized light into linearly polarized light, or changing the polarization direction of linearly polarized light. In particular, a so-called 1Z4 wavelength plate (also called a λλ4 plate) is used as a phase difference plate that changes linearly polarized light into circularly polarized light or changes circularly polarized light into linearly polarized light. A 1Z2 wavelength plate (also referred to as λ 2 plate) is usually used to change the polarization direction of linearly polarized light.

[0049] The elliptically polarizing plate compensates (prevents) coloring (blue or yellow) caused by double bending of the liquid crystal layer of the super twisted nematic (STN) type liquid crystal display device, and displays the above-mentioned coloring! It is used effectively in such cases. Further, the one having a controlled three-dimensional refractive index 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. [0050] 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 the film. It is done. The thickness of the retardation plate is not particularly limited, but is generally about 20 to 150 / ζ πι.

 [0051] Examples of the polymer material include polybutyl alcohol, polybutyral, polymethyl vinylenoether, polyhydroxy ethino rare talylate, hydroxy ethinore cellulose, hydroxypropyl cellulose, methenorescenellose, polycarbonate, poly Arylate, Polysulfone, Polyethylene terephthalate, Polyethylene naphthalate, Polyetherolsulfone, Polyphenylene sulfide, Polyphenylene oxide, Polyallylsulfone, Polyamide, Polyimide, Polyolefin, Polychlorinated butyl, Cellulose polymer, Norbornene resin Or various types of these binary and ternary copolymers, graft copolymers, and blends. These polymer materials become an oriented product (stretched film) by stretching or the like.

 [0052] 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. Can be given. Specific examples of the main chain type liquid crystal polymer include a nematic orientation polyester liquid crystal polymer, a discotic polymer and a cholesteric polymer having a structure in which a mesogenic group is bonded at a spacer portion that imparts flexibility. It is done. Specific examples of side-chain liquid crystal polymers include polysiloxane, polyacrylate, polymetatalylate, or polymalonate as the main chain skeleton, and nematic alignment imparted via a spacer unit consisting of conjugated atomic groups as side chains. And those having a mesogenic moiety that is a unit force of a para-substituted cyclic compound. These liquid crystal polymers are, for example, liquid crystalline on the alignment surface such as those obtained by rubbing the surface of a thin film such as polyimide polybulal alcohol formed on a glass plate, or those obtained by obliquely vapor deposition of oxygen. This is done by developing and heat-treating the polymer solution.

[0053] The retardation plate may have an appropriate retardation according to the purpose of use, such as various wavelength plates and those for the purpose of coloration due to birefringence of the liquid crystal layer and compensation of vision, etc. 2 It is also possible to use a laminate of more than one kind of retardation plate to control optical properties such as retardation. Yes.

 [0054] The elliptically 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. The elliptical polarizing plate or the like that can be formed can be formed by sequentially laminating them separately in the manufacturing process of the liquid crystal display device so as to be a combination of a (reflection type) polarizing plate and a retardation plate. As described above, an optical film such as an elliptically polarizing plate is advantageous in that it has excellent quality stability and lamination workability, and can improve the manufacturing efficiency of a liquid crystal display device.

 [0055] 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 in a slightly oblique direction rather than perpendicular to the screen. As such a visual compensation phase difference plate, for example, a phase difference plate, an alignment film such as a liquid crystal polymer, or a support in which an alignment layer such as a liquid crystal polymer is supported on a transparent substrate can be used. A normal retardation plate uses a polymer film having birefringence 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. Birefringence, such as a polymer film having a birefringence and a birefringence that has a controlled refractive index in the thickness direction that is uniaxially stretched in the plane direction and is also stretched in the thickness direction. A film or the like is used. Examples of the tilted alignment film include a film obtained by bonding a heat-shrink film to a polymer film and subjecting the polymer film to a stretch treatment or Z and shrink treatment under the action of the shrinkage force by heating, or a liquid crystal polymer that is obliquely oriented. Etc. 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 of the liquid crystal cell and expanding the viewing angle for good viewing. Anything suitable for the purpose can be used.

 [0056] In addition, a liquid crystal polymer alignment layer, particularly an optically anisotropic layer composed of a discotic liquid crystal polymer gradient alignment layer, is supported by a triacetyl cellulose film in order to achieve a wide viewing angle with good visibility. The optically compensated retardation plate can be preferably used.

[0057] A polarizing plate obtained by bonding a polarizing plate and a brightness enhancement film is usually used by being provided on the back side of the liquid crystal cell. The brightness enhancement film is a linearly polarized light with a predetermined polarization axis or a predetermined direction when natural light is incident on the backlight of a liquid crystal display device, etc. The polarizing plate, which reflects the circularly polarized light and transmits other light, is a polarizing plate in which a brightness enhancement film is laminated with a polarizing plate. And light other than the predetermined polarization state is reflected without being transmitted. The light reflected on the surface of the brightness enhancement film is further inverted through a reflective layer 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. In addition to increasing the amount of light transmitted through the brightness enhancement film, it is possible to improve the brightness by supplying polarized light that is not easily absorbed by the polarizer and increasing the amount of light that can be used for liquid crystal display image display, etc. is there. That is, when light is incident through the polarizer behind the liquid crystal cell without using a brightness enhancement film, the light having a polarization direction that does not coincide with the polarization axis of the polarizer is It is almost absorbed by the polarizer and does not pass through the polarizer. That is, approximately 50% of the light that is different depending on the characteristics of the polarizer used is absorbed by the polarizer, and the amount of light that can be used for liquid crystal image display is reduced, and the image becomes dark. The brightness enhancement film allows light having a polarization direction that is absorbed by the polarizer to be reflected once by the brightness enhancement film without being incident on the polarizer, and further through a reflective layer or the like provided on the back side thereof. Inverting and re-entering the brightness enhancement film is repeated, and only the polarized light whose polarization direction is such that the polarization direction of the light reflected and inverted between the two can pass through the polarizer is obtained. Is transmitted to the polarizer so that light such as a backlight can be efficiently used for displaying images 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 reflection layer and the like, but the installed diffuser diffuses the light passing therethrough at the same time and simultaneously cancels the polarization state to become a non-polarized state. That is, the light in the natural light state is directed to the reflection layer and the like, is reflected through the reflection layer and the like, passes through the diffusion plate again, 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, uneven brightness of the display screen is reduced. Can provide a uniform and bright screen. By providing a powerful diffuser, the number of times the first incident light is repeatedly reflected increases moderately, coupled with the diffusion function of the diffuser. V. It seems that we were able to provide a display screen.

 [0059] As the brightness enhancement film, for example, a dielectric multilayer thin film or a multilayer laminate of thin film films having different refractive index anisotropies, the linearly polarized light having a predetermined polarization axis is transmitted and other light is transmitted. Reflecting one of the left-handed or right-handed circularly polarized light and transmitting the other light, such as those that show reflective properties, such as oriented films of cholesteric liquid crystal polymer and those oriented liquid crystal layers supported on a film substrate Appropriate things such as those showing the characteristics to be used can be used.

 [0060] Therefore, in the above-described brightness enhancement film that transmits linearly polarized light having a predetermined polarization axis, the transmission light is directly incident on the polarizing plate with the polarization axis aligned, thereby suppressing absorption loss due to the polarizing plate. However, it can be transmitted efficiently. 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 directly incident on a polarizer. However, the circularly polarized light is linearly polarized through a retardation plate in order to suppress absorption loss. It is preferable to make it light and make it enter into a polarizing plate. Note that circularly polarized light can be converted to linearly polarized light by using a 1Z4 wavelength plate as the retardation plate.

 [0061] A retardation plate that functions as a 1Z4 wavelength plate at a wide wavelength in the visible light region or the like exhibits, for example, a retardation plate that functions as a 1Z4 wavelength plate for light-colored light having a wavelength of 55 Onm and other retardation characteristics. It can be obtained by a method of superposing a retardation layer, for example, a retardation layer functioning as a 1Z2 wavelength plate. Therefore, the retardation plate disposed between the polarizing plate and the brightness enhancement film may have a retardation layer force of one layer or two or more layers.

 [0062] It should be noted that the cholesteric liquid crystal layer also reflects circularly polarized light in a wide wavelength range such as a visible light castle by combining two or more layers with different reflection wavelengths in an overlapping structure. Based on this, transmission circular polarization in a wide and wavelength range can be obtained.

 [0063] The polarizing plate may be formed by laminating a polarizing plate such as the above-described polarization-separating polarizing plate and two or more optical layers. Therefore, a reflective elliptical polarizing plate or a semi-transmissive elliptical polarizing plate in which the above-mentioned reflective polarizing plate or semi-transmissive polarizing plate and a retardation plate are combined may be used.

[0064] The optical film in which the optical layer is laminated on a polarizing plate can be formed even in a method of laminating sequentially and separately in the manufacturing process of a liquid crystal display device or the like. These products have excellent quality stability and assembly work! /, And have the advantage of improving the manufacturing process of liquid crystal display devices. For the lamination, an appropriate adhesive means such as an adhesive layer can be used. When the polarizing plate and the other optical layer are bonded, their optical axes can be arranged at an appropriate angle depending on the target retardation characteristics.

 [0065] The optical film with pressure-sensitive adhesive of the present invention is produced by forming a pressure-sensitive adhesive layer on the optical film. The forming method is not particularly limited, and examples thereof include a method of applying and drying a pressure-sensitive adhesive solution, and a method of transferring with a release sheet provided with a pressure-sensitive adhesive layer. The thickness of the pressure-sensitive adhesive layer is not particularly limited, but is preferably about 3 to about LOO / zm, preferably about 10 to 40 / ζ πι. In forming the pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer may be formed after forming the antistatic layer.

 [0066] Constituent materials of the release sheet include synthetic resin films such as paper, polyethylene, polypropylene, and polyethylene terephthalate, rubber sheets, paper, cloth, nonwoven fabric, nets, foam sheets, metal foils, laminates thereof, and the like. Appropriate thin leaves and the like can be mentioned. The surface of the release sheet is subjected to low-adhesion release treatment such as silicone treatment, long-chain alkyl treatment, and fluorine treatment as necessary to improve the peelability of the adhesive layer! / OK!

[0067] In addition, each layer such as an optical film or an adhesive layer of the optical film with an adhesive of the present invention includes, for example, a salicylic acid ester compound, a benzophenol compound, a benzotriazole compound, a cyanoacrylate compound, a nickel complex salt. Something that has UV absorption ability by a method such as a method of treating with a UV absorber such as a compound.

 The optical film with an adhesive of the present invention can be preferably used for forming various image display devices such as a liquid crystal display device. The liquid crystal display device can be formed according to the conventional method. In other words, a liquid crystal display device is generally formed by appropriately assembling components such as a liquid crystal cell, an optical film with an adhesive, 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. As the liquid crystal cell, an arbitrary type such as an arbitrary type such as a vertical type, an STN type, or a π type can be used.

[0069] A liquid crystal display device in which an optical film with an adhesive is disposed on one side or both sides of a liquid crystal cell, Appropriate liquid crystal display devices, such as those using a reflector, can be formed. In that case, the optical film according to the present invention can be placed on one 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 an appropriate 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 knocklight, 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. In general, 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 injecting layer having an isotropy such as a triphenylamine derivative and a light emitting layer having a fluorescent organic solid force such as anthracene. Or a laminate of such a light emitting layer and a perylene derivative or the like electron injection layer, or a stack of these hole injection layer, light emitting layer, and electron injection layer. The composition is known.

 [0071] In an organic EL display device, holes and electrons are injected into an organic light-emitting layer by applying a voltage to a transparent electrode and a metal electrode, and energy generated by recombination of these holes and electrons. Emits light on the principle that it excites the fluorescent material and emits light when the excited fluorescent material returns to the ground state. The mechanism of recombination in the middle is the same as that of a general diode, and as can be expected from this, the current and emission intensity show strong nonlinearity with rectification with respect to the applied voltage.

 [0072] In the 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 is usually formed of a transparent conductor such as indium tin oxide (ITO). A transparent electrode is used as the anode. On the other hand, in order to facilitate electron injection and increase luminous efficiency, it is important to use a material with a low work function for the cathode, and usually metal electrodes such as Mg Ag and A1-Li are used.

[0073] In the organic EL display device having such a configuration, the organic light emitting layer has a thickness of about lOnm. It is made of a thin film. For this reason, the organic light emitting layer transmits light almost completely like the transparent electrode. As a result, light that is incident on the surface of the transparent substrate when not emitting light, passes through the transparent electrode and the organic light emitting layer, and is reflected by the metal electrode again returns to the surface side of the transparent substrate. When viewed, the display surface of the OLED display looks like a mirror.

 [0074] In an organic EL display device including an organic electroluminescent light emitting device including a transparent electrode on a front surface side of an organic light emitting layer that emits light when a voltage is applied and a metal electrode on a back surface side of the organic light emitting layer, A polarizing plate can be provided on the surface side of the electrode, and a retardation plate can be provided between the transparent electrode and the polarizing plate.

 [0075] Since the retardation plate and the polarizing plate have a function of polarizing light incident from the outside and reflected by the metal electrode, the effect of preventing the mirror surface of the metal electrode from being visually recognized by the polarization action. is there. In particular, if the retardation plate is a 1Z4 wavelength plate and the angle between the polarization directions of the polarizing plate and the retardation plate is adjusted to π Z4, the mirror surface of the metal electrode can be completely shielded.

 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 is generally elliptically polarized by the retardation plate, but it is circularly polarized when the retardation plate is a 1Z4 wavelength plate and the angle between the polarization direction of the polarizing plate and the retardation plate is π Ζ4. .

 [0077] 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 is linearly polarized again on the retardation plate. Become. And since this linearly polarized light is orthogonal to the polarization direction of the polarizing plate, it cannot be transmitted through the polarizing plate. As a result, the mirror surface of the metal electrode can be completely shielded.

 Example

 [0078] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the examples, all parts and percentages are based on weight.

 [0079] (Measurement of Tg of adhesive layer)

The Tg of the adhesive layer was determined by the DSC method. Tg was the starting temperature. The measuring device used was a DSC6220 type differential scanning calorimeter manufactured by Seiko Instruments Inc. [0080] (Measurement of internal force (F) caused by thermal stress of optical film)

 F = a-ΔΤ- Ε-1-h

 (Where α is the coefficient of thermal expansion at -60 to 23 ° C, ΔΤ is the temperature difference when 23 ° C is the reference, E is the elastic modulus, 1 is the width, and h is the thickness). It was. The thermal expansion coefficient α was determined by the ΤΜ ΤΜ method. The measuring device used is a TMAZS S6100 type thermomechanical analyzer manufactured by Seiko Insuno Rememb. The elastic modulus E was determined by a tensile test using an autograph AG 1 manufactured by Shimadzu Corporation. l ′ h is the cross-sectional area of the optical film.

[0081] Example 1

 In a reaction vessel equipped with a condenser, a nitrogen inlet, a thermometer and a stirrer, 99.9 parts of isooctyl acrylate, 0.1 part of 2-hydroxyethyl acrylate, and 2,2'-azobisisobutyrate-tolyl 0. 3 parts were added together with ethyl acetate, and reacted at 60 ° C for 4 hours under a nitrogen gas stream. Ethyl acetate was added to the reaction solution, and an acrylic polymer solution with a solid content concentration of 30% ( The weight average molecular weight of the acrylic polymer was 1.6 million). Apply 0.15 parts of trimethylolpropane tolylene diisocyanate per 100 parts of the solid content of the solution and 0.01 parts of a 3-g acrylic adhesive to a separator made of a polyester film surface-treated with a silicone release agent. And heat-treated at 150 ° C for 5 minutes to obtain a 20 μm thick adhesive layer

. As a result of measuring Tg of the pressure-sensitive adhesive layer, it was -62 ° C.

[0082] The pressure-sensitive adhesive layer was transferred to one side of a polarizing plate (NPF-SEG5224DU, manufactured by Nitto Denko Corporation) to obtain an optical film with a pressure-sensitive adhesive. Then, the polarizing plate with the pressure-sensitive adhesive layer was 280 mm X

It was bonded to a 280 mm size non-alkali glass plate with a laminator and allowed to stand for 15 minutes in an autoclave at 50 ° C and 5 atm.

[0083] The coefficient of thermal expansion in the direction of 90 ° with respect to the stretching axis of the polarizing plate α = 5.3 X 10 " ⁵ (1 / ° C)

Elasticity ratio = 3.05 X 10 ⁹ Pa, thickness = 185 / ζ πι, width = 270 mm, calculation of internal force (F) due to thermal contraction at 0 ° C, F = 186 N .

[0084] Example 2

A pressure-sensitive adhesive layer having a thickness of 20 m was obtained in the same manner as in Example 1. The adhesive layer is transferred to one side of a polarizing plate (NPF-TEG5465DU, manufactured by Nitto Denko Corporation). Obtained. Thereafter, the polarizing plate with the pressure-sensitive adhesive layer was bonded to a 280 mm × 280 mm non-alkali glass plate with a laminator, and allowed to stand in an autoclave at 50 ° C. and 5 atm for 15 minutes for sufficient pressure-bonding treatment.

[0085] The coefficient of thermal expansion in the 90 ° direction with respect to the stretching axis of the polarizing plate α = 5.3 X 10 " ⁵ (1 / ° C)

The elastic modulus was 3.6 × 10 ⁹ Pa, the thickness was 105 / ζ πι, the width was 270 mm, and the internal force (F) due to thermal contraction at 0 ° C. was calculated. As a result, F = 124N.

[0086] Example 3

 In a reaction vessel equipped with a condenser, a nitrogen inlet tube, a thermometer and a stirrer, 99.9 parts of 2-ethylhexyl acrylate, 0.1 part of 2-hydroxyethyl acrylate, and 2, 2 ' After adding 0.3 parts of zobisisobutyric-tolyl with ethyl acetate and reacting at 60 ° C for 4 hours under a nitrogen gas stream, ethyl acetate was added to the reaction mixture, and 30% by weight of acrylic acid was added. A polymer solution (weight average molecular weight of acrylic polymer 1.7 million) was obtained. The amount of trimethylolpropane tolylene diisocyanate was 0.15 part per 100 parts of the solid content of the solution. Next, the acrylic pressure-sensitive adhesive was applied to a separator made of a polyester film surface-treated with a silicone-based release agent, and heat-treated at 150 ° C. for 5 minutes to obtain an adhesive layer having a thickness of 20 μm. As a result of measuring Tg of the pressure-sensitive adhesive layer, it was −60 ° C.

 The pressure-sensitive adhesive layer was transferred to one side of a polarizing plate (NPF-SEG5224DU, manufactured by Nitto Denko Corporation) to obtain an optical film with a pressure-sensitive adhesive. Thereafter, the polarizing plate with the pressure-sensitive adhesive layer was bonded to a 280 mm × 280 mm non-alkali glass plate with a laminator and left in an autoclave at 50 ° C. and 5 atm for 15 minutes for sufficient pressure-bonding treatment.

 [0088] Example 4

In a reaction vessel equipped with a condenser tube, nitrogen inlet tube, thermometer and stirrer, 99 parts of acrylate, 1 part of 4-hydroxyethyl acrylate, and 2,2'-azobisisobuty After adding 0.3 parts of ethyl acetate together with ethyl acetate and reacting in a nitrogen gas stream at 60 ° C for 4 hours, ethyl acetate was added to the reaction mixture to obtain an acrylic polymer solution having a solid content concentration of 30% by weight ( The weight average molecular weight of the acrylic polymer was 1.65 million. Per 100 parts solids of the solution 0.3 parts dibenzoyl peroxide and 0.02 parts trimethylolpropan xylylene An acrylic adhesive was obtained by blending diisocyanate and 0.2 part of 3 glycidoxypropyltrimethoxysilane. Next, the acrylic pressure-sensitive adhesive was coated on a separator having a polyester film surface that was surface-treated with a silicone-based release agent, and heat-treated at 155 ° C. for 3 minutes to obtain a pressure-sensitive adhesive layer having a thickness of 20 m. The Tg of the pressure-sensitive adhesive layer was measured and found to be 38 ° C.

 The pressure-sensitive adhesive layer was transferred to one surface of a polarizing plate (NPF-SEG5224DU, manufactured by Nitto Denko Corporation) to obtain an optical film with a pressure-sensitive adhesive. Thereafter, the polarizing plate with the pressure-sensitive adhesive layer was bonded to a 280 mm × 280 mm non-alkali glass plate with a laminator and left in an autoclave at 50 ° C. and 5 atm for 15 minutes for sufficient pressure-bonding treatment.

 [0090] Comparative Example 1

 In a reaction vessel equipped with a condenser, a nitrogen inlet tube, a thermometer, and a stirrer, 95 parts of acrylic acid propyl, 5 parts of acrylic acid, and 0.3 part of 2,2'-azobisisobutyric-tolyl After adding together with ethyl acetate and reacting at 60 ° C for 4 hours under a nitrogen gas stream, ethyl acetate was added to the reaction solution, and an acrylic polymer solution (acrylic polymer with a solid content concentration of 30% by weight) was added. The weight average molecular weight was 2 million). An acrylic pressure-sensitive adhesive was obtained by blending 0.6 part of trimethyloxysilane per 100 parts of the solid content of the solution. Next, the acrylic pressure-sensitive adhesive was coated on a polyester film-strength separator surface-treated with a silicone-based release agent, and heat-treated at 150 ° C. for 5 minutes to obtain a pressure-sensitive adhesive layer having a thickness of 20 m. The Tg of the pressure-sensitive adhesive layer was measured and found to be 30 ° C.

 The pressure-sensitive adhesive layer was transferred to one surface of a polarizing plate (NPF-SEG5224DU, manufactured by Nitto Denko Corporation) to obtain an optical film with a pressure-sensitive adhesive. Thereafter, the polarizing plate with the pressure-sensitive adhesive layer was bonded to a 280 mm × 280 mm non-alkali glass plate with a laminator and left in an autoclave at 50 ° C. and 5 atm for 15 minutes for sufficient pressure-bonding treatment.

 [0092] Comparative Example 2

A pressure-sensitive adhesive layer having a thickness of 20 m was obtained in the same manner as in Comparative Example 1. The pressure-sensitive adhesive layer was transferred to one side of a polarizing plate (NPF-TEG5465DU, manufactured by Nitto Denko Corporation) used in Example 2 to obtain an optical film with a pressure-sensitive adhesive. Then, the polarizing plate with the adhesive layer is attached to a 280 mm X 280 mm It was pasted on a non-alkali glass plate with a laminator and left in an autoclave at 50 ° C and 5 atm for 15 minutes for sufficient pressure bonding.

[0093] The following evaluations were performed on the optical films with pressure-sensitive adhesives obtained in Examples and Comparative Examples (samples bonded to non-alkali glass plates). The results are shown in Table 1.

[0094] <Warpage amount>

 After the above sample was treated for 30 minutes in the low temperature range of 0 ° C or below shown in Table 1, it was 23 ° C, 55 ° C.

In an atmosphere of% RH, it was placed on a level and uneven surface, and the amount of warpage at four points in the surface was measured using a gap gauge. The amount of warpage was the average of the four points. The evaluation criteria are as follows.

 ◯: Glass warpage is less than 0.5 mm.

 Δ: Glass warpage is 0.5 to 1. Omm.

 X: Warpage of glass exceeds 1. Omm.

[0095] [Table 1]

Industrial applicability

 The optical film with an adhesive of the present invention is suitable for containing a stretched film as an optical film, and can be suitably applied to image display devices such as liquid crystal display devices, organic EL display devices, and PDPs.

Claims

The scope of the claims

 [1] In an optical film with an adhesive having an adhesive layer on at least one side of the optical film,

 An optical film with an adhesive, wherein the adhesive layer has a Tg of −35 ° C. or lower.

[2] Internal force (F) resulting from thermal stress of the optical film,

 F = a-ΔΤ-Ε -1-h

 (Where α is the coefficient of thermal expansion from –60 to 23 ° C, ΔΤ is the temperature difference when 23 ° C is the reference, E is the elastic modulus, 1 is the width, and h is the thickness). In case,

 The pressure-sensitive adhesive according to claim 1, wherein the optical film has a stretched film, and an internal force (F) generated in a 90 ° direction with respect to the stretch axis of the stretched film at 0 ° C is 50 N or more. With optical film.

[3] The optical film with an adhesive according to [1], wherein the optical film contains a polarizing plate and Z or a retardation plate.

4. The optical film with an adhesive according to claim 2, wherein the optical film contains a polarizing plate and Z or a retardation plate.

[5] An image display device using at least one optical film with an adhesive according to any one of claims 1 to 4.