Method for manufacturing image display device and method for manufacturing image display device with front transparent member

Abstract

The invention relates to a method for manufacturing an image display device and a method for manufacturing an image display device with a front transparent member, which can ensure that the time for suppressing polyalkylene of polyvinyl alcohol of the image display device is long. A method for manufacturing an image display device includes a step of heating a laminate in which a resin film (40) with a first adhesive layer, a polarizing plate (30), a second adhesive layer (50), and an image display unit (60) are laminated in this order. The resin film (42) of the resin film (40) with the first adhesive layer is laminated in direct contact with the first adhesive layer (41). The moisture permeation rate (1) of the resin film (40) with the first adhesive layer is 5 g / (m < 2 >. 24 hours) or more and 20 g / (m < 2 >. 24 hours) or less, and the moisture permeation rate (2) is 10 g / (m < 2 >. 24 hours) or more. The first adhesive layer (41) side of the resin film (40) with the first adhesive layer of the laminate is laminated on the polarizing plate (30) side.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing an image display device including a polarizing plate, where the polarizing plate has a polarizer formed of a polyvinyl alcohol-based resin film, and the present invention also relates to a method for manufacturing an image display device with a front transparent member. Background Art

[0002] Image display devices such as liquid crystal display devices and organic EL display devices are also used as in-vehicle image display devices such as navigation devices and rearview monitors, and their applications are expanding. Along with the expansion of the applications of image display devices, high durability in a more severe environment than previously required (for example, in a high-temperature environment) is required for image display devices and polarizing plates including polarizers formed of polyvinyl alcohol-based resin films, which are part of image display devices.

[0003] An image display device (an image display device with a front transparent member) having the following laminated structure is used as an in-vehicle image display device, that is, an image display unit is attached to one surface of a polarizing plate via an adhesive layer and a bonding agent layer, and a front transparent member (a transparent resin plate, glass, a touch panel, etc.) on the observation side is attached to the other surface of the polarizing plate via an adhesive layer and a bonding agent layer. In order to improve the durability of such an image display device with a front transparent member, for example, as described in Patent Document 1, a laminate having a configuration of an adhesive layer, a polarizing plate, and an adhesive layer image display unit before attaching the front transparent member is heated (aged).

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2021-179604 Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] In the invention described in Patent Document 1, when a front transparent member is bonded to a laminate after heat treatment (aging), and the resulting image display device with the front transparent member is exposed to a high-temperature environment, for the polarizing plate that is a constituent member of the image display device with the front transparent member, polyene formation of the polyvinyl alcohol-based resin forming the polarizing plate can also be suppressed, thereby suppressing a decrease in the transmittance of the polarizing plate. However, the inventors have found that if the time from the heat treatment to the bonding of the front transparent member is long, when the image display device with the front transparent member is exposed to a high-temperature environment, the effect of suppressing polyene formation of the polyvinyl alcohol-based resin forming the polarizing plate cannot be exerted, and the effect of suppressing a decrease in its transmittance cannot be exerted either. In addition, if the time until the front transparent member is bonded is short, multiple heat treatments or the like must be performed, resulting in a significant reduction in the productivity of the image display device with the front transparent member.

[0009] In view of the above situation, an object of the present invention is to provide a method for manufacturing an image display device that can extend the time from the heat treatment to the bonding of the front transparent member. In other words, the object is to provide a method for manufacturing an image display device with a front transparent member that has high productivity.

[0010] Means for Solving the Problem

[0011] [[Invention 1]]

[0012] A method for manufacturing an image display device, which is a method for manufacturing an image display device in which a resin film with a first adhesive layer, a polarizing plate having a polarizing film formed of a polyvinyl alcohol-based resin film, a second adhesive layer, and an image display unit are sequentially laminated.

[0013] The manufacturing method includes: a step of heating a laminate in which the resin film with the first adhesive layer, the polarizing plate, the second adhesive layer, and the image display unit are sequentially laminated.

[0014] In the resin film with the first adhesive layer, the resin film and the first adhesive layer are laminated in direct contact.

[0015] The water permeation rate (1) of the resin film with the first adhesive layer, calculated using the following formula (A), is 5 g / (m 2 ·24 hours) or more and 20 g / (m 2 ·24 hours) or less.

[0016] The water permeation rate (2) of the resin film with the first adhesive layer, calculated using the following formula (B), is 10 g / (m 2 ·24 hours) or more.

[0017] The resin film with the first adhesive layer of the above laminate is laminated on the polarizing plate side with the first adhesive layer side facing up.

[0018] (Mass of the resin film with the first adhesive layer at 48 hours - Mass of the resin film with the first adhesive layer at 24 hours) / (m 2 ·24 hours) Equation (A)

[0019] (Mass of the resin film with the first adhesive layer at 72 hours - Mass of the resin film with the first adhesive layer at 48 hours) / (m 2 ·24 hours) Equation (B)

[0020] (Note that the so-called mass of the resin film with the first adhesive layer at 24 hours in Equation (A) and Equation (B) refers to the mass per unit area when the resin film with the first adhesive layer processed to a moisture permeable area of 28.26 cm 2 is placed in a moisture permeation cup containing about 45 g of calcium chloride and left to stand in a constant temperature machine at a temperature of 40 °C and a relative humidity of 90% for 24 hours. The so-called mass of the resin film with the first adhesive layer at 48 hours refers to the mass per unit area when the resin film with the first adhesive layer processed to a moisture permeable area of 28.26 cm 2 is placed in a moisture permeation cup containing about 45 g of calcium chloride and left to stand in a constant temperature machine at a temperature of 40 °C and a relative humidity of 90% for 48 hours.

[0021] The so-called mass of the resin film with the first adhesive layer at 72 hours refers to the mass per unit area when the resin film with the first adhesive layer processed to a moisture permeable area of 28.26 cm 2 is placed in a moisture permeation cup containing about 45 g of calcium chloride and left to stand in a constant temperature machine at a temperature of 40 °C and a relative humidity of 90% for 72 hours.)

[0022] [Invention 2]

[0023] According to the method for manufacturing an image display device described in [Invention 1], wherein the moisture permeation rate (2) of the resin film with the first adhesive layer is 40 g / (m 2 ·24 hours) or less.

[0024] [Invention 3]

[0025] According to the method for manufacturing an image display device described in [Invention 1], wherein the moisture permeation rate (1) of the resin film with the first adhesive layer is 5 g / (m2 · More than 24 hours and less than 15 g / (m 2 · 24 hours).

[0026] The water vapor transmission rate (2) of the resin film with the first adhesive layer is 10 g / (m 2 · More than 24 hours and less than 25 g / (m 2 · 24 hours).

[0027] [Invention 4]

[0028] A method for manufacturing an image display device according to any one of [Invention 1] to [Invention 3], characterized in that the value of the water vapor transmission rate (2) of the resin film with the first adhesive layer is greater than the value of the water vapor transmission rate (1) of the resin film with the first adhesive layer.

[0029] [Invention 5]

[0030] A method for manufacturing an image display device according to any one of [Invention 1] to [Invention 4], wherein the polarizing plate has the polarizer and the protective film, and the protective film is laminated via an adhesive layer on the surface of the polarizer on the side of the first adhesive layer,

[0031] The water vapor permeability of the protective film at a temperature of 40 °C and a relative humidity of 90% is 1000 (g / m 2 · 24 hours) or less.

[0032] [Invention 6]

[0033] A method for manufacturing an image display device with a front transparent member, the manufacturing method including: a step of peeling the resin film from the image display device obtained by using the method for manufacturing an image display device according to any one of [Invention 1] to [Invention 5] and attaching the front transparent member to the first adhesive layer.

[0034] Advantages of the Invention

[0035] The present invention can extend the time until an image display device with a front transparent member is manufactured from an image display device, and can improve the productivity of the image display device with a front transparent member. Description of the Drawings

[0036] Figure 1 It is a schematic cross-sectional view showing an image display device with a front transparent member.

[0037] Figure 2 It is a schematic cross-sectional view showing an image display device.

[0038] Figure 3It is a schematic cross-sectional view showing a polarizing plate included in an image display device. Detailed implementation mode

[0039] Hereinafter, a method for manufacturing an image display device of the present invention will be described.

[0040] Figure 1 An image display device 10 with a front transparent member is shown. The image display device 10 with a front transparent member can be manufactured from Figure 2 the image display device 20 shown. The image display device 10 with a front transparent member and the manufacturing method of the image display device with a front transparent member will be described later.

[0041] <Image display device>

[0042] Figure 2 An image display device 20 manufactured by the manufacturing method of the image display device of the present embodiment is shown. The image display device 20 sequentially includes a resin film 40 with a first adhesive layer, a polarizing plate 30 having a polarizing sheet 31 formed of a polyvinyl alcohol-based resin film, a second adhesive layer 50, and an image display unit 60.

[0043] In the resin film 40 with a first adhesive layer, the resin film 42 and the first adhesive layer 41 are laminated in direct contact.

[0044] In the image display device 20, the first adhesive layer 41 side of the resin film 40 with a first adhesive layer is laminated on the polarizing plate 30 side.

[0045] Hereinafter, in the image display device 20, the side closer to the image display unit 60 is referred to as the unit side, and the side closer to the resin film 42 is referred to as the observation side.

[0046] In the present invention, in order to manufacture an image display device, in a laminate in which an adhesive layer, a polarizing plate, an adhesive layer, and an image display unit are laminated in sequence, when a heating process is performed, a resin film 40 with a first adhesive layer is laminated, and the resin film with the first adhesive layer satisfies the water permeation rate (1) and the water permeation rate (2) described below. Although the details of the mechanism of action of the present invention are unclear in some parts, it can be speculated as follows. When the above laminate is heated and then left standing, the polarizing plate contained in the laminate and the adhesive layers on both sides of the polarizing plate will absorb the surrounding moisture again. It is considered that if an image display device with a front transparent member is manufactured from the laminate in a moisture-absorbed state and the image display device with the front transparent member is continuously exposed to a high-temperature environment, polyene formation will occur due to dehydration of polyvinyl alcohol, resulting in a decrease in the transmittance of the image display device with the front transparent member. By setting the water permeation rate (1) and the water permeation rate (2) described below within a specific range, the present invention can efficiently reduce the amount of moisture during the heating process of the laminate and can also suppress moisture absorption even when left standing after the heating process. Since the image display device obtained by the manufacturing method of the present invention can suppress moisture absorption, polyene formation of polyvinyl alcohol can be suppressed, and a decrease in transmittance can be suppressed, so that good durability can be achieved. It should be noted that the present invention can be explained regardless of the above mechanism.

[0047] Hereinafter, the elements constituting or capable of constituting the image display device 20 will be described in detail.

[0048] <Polarizing plate>

[0049] As Figure 3 shown, the polarizing plate 30 has, for example, a polarizer 31 and a first protective film 33 that protects the polarizer 31.

[0050] The polarizing plate 30 is, for example, as Figure 3 shown, and a first protective film 33 is laminated on the surface of the polarizer 31 on the viewing side via an adhesive layer 32. That is, as the image display device 20, it can be said that a protective film is laminated on the surface of the polarizer 31 on the side of the first adhesive layer 41 via the adhesive layer 32. In the image display device 20 having the polarizing plate 30 in this case, the first adhesive layer 41 of the resin film 40 with the first adhesive layer is laminated on the viewing side of the first protective film 33.

[0051] The polarizing plate 30 can be as Figure 3On the cell side surface of the polarizer 31, a second protective film 34 is laminated via an adhesive layer 32. In the image display device 20 having the polarizing plate 30 in this case, a second adhesive layer 50 is laminated on the cell side of the second protective film 34. It should be noted that, for example, the polarizing plate 30 may not have the second protective film 34. When the polarizing plate 30 does not have the second protective film 34, the surface on the cell side of the polarizer 31 is adhered to the image display unit 60 via an adhesive or an adhesive agent. In addition, the polarizing plate 30 preferably has at least the first protective film 33 among the first protective film 33 and the second protective film 34, but it may not have the first protective film 33. When the polarizing plate 30 does not have the first protective film 33, the first adhesive layer 41 is directly laminated on the viewing side surface of the polarizer 31.

[0052] [Polarizer]

[0053] The polarizer 31 is obtained by adsorbing and orienting a dichroic dye in a polyvinyl alcohol-based resin film. As the polyvinyl alcohol-based resin, for example, a resin obtained by saponifying a polyvinyl acetate-based resin can be used. The saponification degree of the polyvinyl acetate-based resin is preferably 85 mol% or more, more preferably 90 mol% or more, and further preferably 99 mol% or more.

[0054] As the polyvinyl acetate-based resin, for example, polyvinyl acetate which is a homopolymer of vinyl acetate, a copolymer of vinyl acetate and other monomers copolymerizable therewith, etc. can be used. As other monomers copolymerizable therewith, for example, unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, etc. can be cited.

[0055] The degree of polymerization of the polyvinyl alcohol-based resin is preferably 1000 or more and 10000 or less, more preferably 1500 or more and 5000 or less.

[0056] The polyvinyl alcohol-based resin can be modified. As the modified polyvinyl alcohol-based resin, for example, polyvinyl formal, polyvinyl acetal, polyvinyl butyral, etc. modified with aldehydes can be cited.

[0057] As the dichroic dye, for example, iodine, water-soluble dichroic dyes, etc. can be cited.

[0058] The thickness of the polarizer 31 is not particularly limited, preferably 3 μm or more and 35 μm or less, more preferably 4 μm or more and 30 μm or less, and further preferably 5 μm or more and 25 μm or less. By making the thickness of the polarizer 35 μm or less, it is possible to suppress the influence of the reduction of the optical characteristics of the polarizer caused by the polyene formation of the polyvinyl alcohol-based resin in a high-temperature environment.

[0059] The method for manufacturing the polarizer 31 can adopt a well-known method. As this manufacturing method, for example, a polyvinyl alcohol-based resin film is used as the raw material film, and a swelling process, a dyeing process, a cross-linking process, a cleaning process, and a drying process are successively performed. The swelling process is a processing step of swelling the raw material film by immersing it in a swelling liquid. The dyeing process is a processing step of adsorbing and orienting dichroic pigments in the film by immersing the film after the swelling process in a dyeing liquid containing dichroic pigments. The cross-linking process is a processing step of performing a cross-linking treatment by bringing a cross-linking liquid into contact with the film. During each process, that is, before, after, or during any one or more processing steps, a uniaxial stretching treatment as a stretching process can be implemented.

[0060] 〔Protective film〕

[0061] The first protective film 33 is not particularly limited, and various transparent protective films that can be used in a polarizing plate can be adopted. As the material constituting the protective film, for example, a thermoplastic resin with excellent transparency, mechanical strength, thermal stability, water resistance, isotropy, etc. can be used. As the above-mentioned thermoplastic resin, for example, cellulose ester-based resins such as triacetyl cellulose, polyester-based resins such as polyethylene terephthalate and polyethylene naphthalate, polyethersulfone-based resins, polysulfone-based resins, polycarbonate-based resins, polyamide-based resins such as nylon and aromatic polyamide, polyimide-based resins, polyolefin-based resins such as polyethylene, polypropylene, and ethylene-propylene copolymer, (meth)acrylic-based resins, cyclic polyolefin-based resins (norbornene-based resins) having a ring system or a norbornene structure, polyarylate-based resins, polystyrene-based resins, polyvinyl alcohol-based resins, and mixtures thereof can be cited. In addition, the protective film can use a cured layer formed of a thermosetting resin or an ultraviolet curable resin such as (meth)acrylic-based, urethane-based, acrylic urethane-based, epoxy-based, and silicone-based resins. Among them, cellulose ester-based resins, polycarbonate-based resins, (meth)acrylic-based resins, cyclic polyolefin-based resins, and polyester-based resins are suitable.

[0062] On the surface of the protective film that is not adhered to the polarizer, functional layers such as a hard coat, an antireflection layer, an anti-blocking layer, a diffusion layer, or an antiglare layer can be provided. It should be noted that the above-mentioned functional layers such as the hard coat, the antireflection layer, the anti-blocking layer, the diffusion layer, and the antiglare layer can be provided not only on the protective film itself but also separately as a layer different from the protective film.

[0063] Surface treatment can be performed on any one or both of the surface of the protective film adhered to the polarizer and the surface of the polarizer adhered to the protective film. As the surface treatment, for example, corona treatment, plasma treatment, primer treatment, saponification treatment, etc. can be cited.

[0064] The thickness of the first protective film 33 is not particularly limited, for example, it is 1 μm or more and 500 μm or less, preferably 1 μm or more and 300 μm or less, more preferably 5 μm or more and 300 μm or less, and still more preferably 5 μm or more and 100 μm or less.

[0065] The moisture permeability of the first protective film 33 in an environment of 40 °C and 90% relative humidity is preferably 1000 (g / m 2 ·24 h) or less. The above moisture permeability is preferably 200 (g / m 2 ·24 h) or more.

[0066] The above moisture permeability is more preferably 200 (g / m 2 ·24 h) or more and 900 (g / m 2 ·24 h) or less, and still more preferably 200 (g / m 2 ·24 h) or more and 600 (g / m 2 ·24 h) or less, and even more preferably 200 (g / m 2 ·24 h) or more and 300 (g / m 2 ·24 h) or less.

[0067] The measurement of the moisture permeability can be carried out according to the moisture permeability test (cup method) of JIS Z0208.

[0068] If the moisture permeability of the first protective film 33 is 1000 (g / m 2 ·24 h) or less, the transfer of moisture to the polarizer 31 can be suppressed, and it is also easy to suppress the moisture absorption of the polarizer after the heat treatment. As a result, it is presumed that polyene formation is difficult, so the moisture permeability of the first protective film 33 is preferably 1000 (g / m 2 ·24 h) or less.

[0069] The second protective film 34 can be appropriately selected and used from the above various protective films in the same manner as the first protective film 33. The second protective film 34 can be a film of a different type from the first protective film 33, or a film of the same type as the first protective film 33.

[0070] The moisture permeability of the second protective film 34 in an environment of 40 °C and 90% relative humidity is preferably 1000 (g / m 2 ·24 h) or less.

[0071] If the moisture permeability of the second protective film 34 is 1000 (g / m 2· If it is less than 1000 (g / m 2 ·24 hours), in addition to suppressing the transfer of moisture from the second adhesive layer 50 side to the polarizer 31, it is also easy to suppress the moisture absorption of the polarizer after the heat treatment. As a result, it is presumed that polyene formation is difficult to proceed. Therefore, the moisture permeability of the second protective film 34 is preferably 1000 (g / m 2 ·24 hours) or less.

[0072] 〔Adhesive layer〕

[0073] As the adhesive for forming the adhesive layer 32, various adhesives that can be used in a polarizing plate can be applied. For example, isocyanate-based adhesives, polyvinyl alcohol-based adhesives, gelatin-based adhesives, vinyl-based latexes, aqueous polyesters, etc. can be cited. These adhesives are usually used as adhesives formed from an aqueous solution (aqueous adhesives) and contain 0.5 to 60% by weight of a solid component. Among them, polyvinyl alcohol-based adhesives are preferred, and polyvinyl alcohol-based adhesives containing an acetoacetyl group are more preferred.

[0074] The above-mentioned aqueous adhesive may also contain a crosslinking agent. As the crosslinking agent, a compound having at least two functional groups reactive with components such as the polymer constituting the adhesive in one molecule is usually used. For example, alkylenediamines; isocyanates; epoxies; aldehydes; amino-formaldehydes such as hydroxymethylurea and hydroxymethylmelamine can be cited. The blending amount of the crosslinking agent in the adhesive is usually about 10 to 60 parts by weight with respect to 100 parts by weight of components such as the polymer constituting the adhesive.

[0075] As the above-mentioned adhesive, in addition to the above-mentioned aqueous adhesive, energy ray curable adhesives such as ultraviolet curable adhesives and electron beam curable adhesives can also be cited. As the energy ray curable adhesive, for example, (meth)acrylate-based adhesives can be cited. As the curable component in the (meth)acrylate-based adhesive, for example, a compound having a (meth)acryloyl group and a compound having a vinyl group can be cited. As the compound having a (meth)acryloyl group, for example, (meth)acrylic acid linear alkyl esters having 1 to 20 carbon atoms, (meth)acrylic acid alicyclic alkyl esters, (meth)acrylic acid polycyclic alkyl esters, etc. (meth)acrylic acid alkyl esters; (meth)acrylates containing hydroxyl groups; (meth)acrylic acid glycidyl esters and other (meth)acrylates containing epoxy groups. The (meth)acrylate-based adhesive may contain nitrogen-containing monomers such as hydroxyethyl (meth)acrylamide, N-methylol (meth)acrylamide, N-methoxymethyl (meth)acrylamide, N-ethoxymethyl (meth)acrylamide, (meth)acrylamide, (meth)acryloylmorpholine. The (meth)acrylate-based adhesive may also contain polyfunctional monomers such as tripropylene glycol diacrylate, 1,9-nonanediol diacrylate, tricyclodecane dimethanol diacrylate, cyclic trimethylolpropane formal acrylate, dioxane glycol diacrylate, and EO-modified diglycerol tetraacrylate as crosslinking components. In addition, a compound having an epoxy group or an oxetanyl group can also be used as a cationic polymerization curable adhesive. The compound having an epoxy group is not particularly limited as long as it has at least two epoxy groups in the molecule, and various well-known curable epoxy compounds can be used.

[0076] The above-mentioned adhesive may also contain appropriate additives as needed. As the additives, for example, coupling agents such as silane coupling agents and titanium coupling agents, adhesion promoters such as ethylene oxide, ultraviolet absorbers, anti-degradants, dyes, processing aids, ion trappers, antioxidants, tackifiers, fillers, plasticizers, leveling agents, anti-foaming agents, antistatic agents, heat stabilizers, hydrolysis-resistant stabilizers, etc. can be cited.

[0077] The above-mentioned adhesive can be applied to either the protective film side or the polarizer side, or both. After lamination, a drying process is carried out to form an adhesive layer composed of a coated and dried layer. After the drying process, ultraviolet rays or electron beams can be irradiated as needed.

[0078] The thickness of the adhesive layer 32 is not particularly limited. For example, in the case of using an aqueous adhesive or the like, it is preferably about 30 to 5000 nm, more preferably about 100 to 1000 nm. For example, in the case of using an ultraviolet curable adhesive, an electron beam curable adhesive, etc., it is preferably about 0.1 to 100 μm, more preferably about 0.5 to 10 μm.

[0079] <Resin film with a first adhesive layer>

[0080] 〔Resin film〕

[0081] Examples of the resin constituting the resin film 40 include polyolefin resins such as polyethylene resins and polypropylene resins; cyclic polyolefin resins; polyester resins such as polyethylene terephthalate and polyethylene naphthalate; polycarbonate resins; (meth)acrylic resins, etc. Among them, polyester resins such as polyethylene terephthalate are preferred. The resin film may have a single-layer structure or a multilayer structure of two or more layers. The resin film may be a film that has been subjected to a stretching treatment such as uniaxial stretching or biaxial stretching.

[0082] The resin film 40 can be provided with a release layer by treating the surface with a release agent. Examples of the release agent include silicone-based release agents, etc. In this case, the resin film 40 with the first adhesive layer is formed by directly laminating the first adhesive layer 41 on the surface of the resin film 40 that has been subjected to the release treatment.

[0083] 〔First adhesive layer〕

[0084] As the adhesive for forming the first adhesive layer 41, various adhesives that can be used in an image display device can be applied. Examples include rubber-based adhesives, acrylic adhesives, silicone-based adhesives, urethane-based adhesives, vinyl alkyl ether-based adhesives, polyvinyl alcohol-based adhesives, polyvinyl pyrrolidone-based adhesives, polyacrylamide-based adhesives, cellulose-based adhesives, etc. Among them, acrylic adhesives are suitable. The above acrylic adhesives are adhesives containing an acrylic polymer as a base polymer, and examples thereof include the acrylic adhesives described in Japanese Patent Application Laid-Open No. 2017-75998, etc.

[0085] The acrylic polymer in the above acrylic-based adhesive has a monomer unit of (meth)acrylic acid alkyl ester as the main backbone. As the (meth)acrylic acid alkyl ester, (meth)acrylic acid alkyl esters having 1 to 20 carbon atoms in the alkyl group can be suitably used, and the content of the (meth)acrylic acid alkyl ester is preferably 40% by weight or more, more preferably 60% by weight or more, based on the total amount of monomer components constituting the base polymer. In addition, from the viewpoint of being able to adjust the adhesiveness of the adhesive, monomer units such as nitrogen-containing monomer units and hydroxyl group-containing monomers can be included. Further, in order to form a crosslinked structure in the adhesive layer, a crosslinking agent can be used. As the crosslinking agent, for example, commonly used crosslinking agents such as isocyanate-based crosslinking agents, epoxy-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, carbodiimide-based crosslinking agents, and metal chelate-based crosslinking agents can be used. The amount of the crosslinking agent used is usually 10 parts by weight or less, preferably 5 parts by weight or less, based on 100 parts by weight of the base polymer.

[0086] In the above adhesive, from the viewpoint of being able to adjust the adhesive force, a silane coupling agent; tackifiers such as terpene-based tackifiers, styrene-based tackifiers, phenol-based tackifiers, rosin-based tackifiers, and epoxy-based tackifiers can be added. In addition, from the viewpoint of improving light resistance, an ultraviolet absorber can be added. In addition to the components exemplified above, in the adhesive, plasticizers, softeners, anti-degradants, fillers, colorants, antioxidants, surfactants, antistatic agents, etc. can also be used within the range that does not impair the characteristics of the adhesive.

[0087] As a method for forming the adhesive layer, for example, the following methods can be exemplified, etc., that is, a method of applying the above adhesive to a separator or the like that has been subjected to a peeling treatment, drying to form an adhesive layer, and then transferring it to a polarizing film or the like; or a method of applying the above adhesive to a polarizing film or the like and drying to form an adhesive layer.

[0088] [[Water permeation rate]]

[0089] The water permeation rate of the resin film 40 with the first adhesive layer is within a specific range.

[0090] Specifically, the water permeation rate (1) of the resin film 40 with the first adhesive layer is 5 g / (m 2 ·24 h) or more and 20 g / (m 2 ·24 h) or less. In addition, the water permeation rate (2) of the resin film 40 with the first adhesive layer is 10 g / (m 2 ·24 h) or more.

[0091] The above water permeation rate (1) can be obtained by the following formula (A). The above water permeation rate (2) can be obtained by the following formula (B).

[0092] (Mass of the resin film with the first adhesive layer at 48 hours - Mass of the resin film with the first adhesive layer at 24 hours) / (m 2 · 24 hours) (A)

[0093] (Mass of the resin film with the first adhesive layer at 72 hours - Mass of the resin film with the first adhesive layer at 48 hours) / (m 2 · 24 hours) (B)

[0094] The "mass of the resin film with the first adhesive layer at 24 hours" in the above formula (A) and formula (B) represents the following value. The "mass of the resin film with the first adhesive layer at 24 hours" is the mass per unit area when the resin film with the first adhesive layer processed to a moisture permeable area of 28.26 cm 2 is placed in a moisture permeation cup containing about 45 g of calcium chloride and left standing in a constant temperature machine at a temperature of 40 °C and a relative humidity of 90% for 24 hours.

[0095] The "mass of the resin film with the first adhesive layer at 48 hours" in the above formula (A) represents the following value. The "mass of the resin film with the first adhesive layer at 48 hours" is the mass per unit area when the resin film with the first adhesive layer processed to a moisture permeable area of 28.26 cm 2 is placed in a moisture permeation cup containing about 45 g of calcium chloride and left standing in a constant temperature machine at a temperature of 40 °C and a relative humidity of 90% for 48 hours.

[0096] The "mass of the resin film with the first adhesive layer at 72 hours" in the above formula (B) represents the following value. The "mass of the resin film with the first adhesive layer at 72 hours" is the mass per unit area when the resin film with the first adhesive layer processed to a moisture permeable area of 28.26 cm 2 is placed in a moisture permeation cup containing about 45 g of calcium chloride and left standing in a constant temperature machine at a temperature of 40 °C and a relative humidity of 90% for 72 hours.

[0097] By making the moisture permeation rate of the resin film 40 with the first adhesive layer within the above specific range, it is possible to easily remove moisture from the polarizing plate 31 in the subsequent heating process while suppressing the absorption of moisture by the polarizing plate 31 after the heating process.

[0098] The moisture permeation rate (1) of the resin film 40 with the first adhesive layer is preferably 5 g / (m 2 · 24 hours) or more and 15 g / (m2 · per 24 hours), more preferably 5 g / (m 2 · per 24 hours) or more and 11 g / (m 2 · per 24 hours) or less, further preferably 5 g / (m 2 · per 24 hours) or more and 7 g / (m 2 · per 24 hours) or less.

[0099] The water permeation rate (2) of the resin film 40 with the first adhesive layer is preferably such that the water permeation rate (2) is 10 g / (m 2 · per 24 hours) or more and 40 g / (m 2 · per 24 hours) or less, more preferably 10 g / (m 2 · per 24 hours) or more and 25 g / (m 2 · per 24 hours) or less, further preferably 10 g / (m 2 · per 24 hours) or more and 15 g / (m 2 · per 24 hours) or less.

[0100] Regarding the water permeation rate (1) and the water permeation rate (2) of the resin film 40 with the first adhesive layer, it is preferred that the water permeation rate (1) is 5 g / (m 2 · per 24 hours) or more and 15 g / (m 2 · per 24 hours) or less, and the water permeation rate (2) is 10 g / (m 2 · per 24 hours) or more and 25 g / (m 2 · per 24 hours) or less.

[0101] The water permeation rate (1) and the water permeation rate (2) of the resin film 40 with the first adhesive layer preferably satisfy the above numerical ranges in the range where the water permeation rate (2) is equal to or greater than the water permeation rate (1), and more preferably satisfy the above numerical ranges in the range where the water permeation rate (2) is greater than the water permeation rate (1).

[0102] The water permeation rate (1) and the water permeation rate (2) of the resin film 40 with the first adhesive layer can be adjusted, for example, by the type of the resin film 42, the thickness of the resin film 42, the type of the first adhesive layer 41, the thickness of the first adhesive layer 41, and the moisture permeability of the first adhesive layer 41. If the water permeation rate (1) and the water permeation rate (2) of the resin film 40 with the first adhesive layer are within the above specific ranges, there are no particular limitations on the type of the resin film 42, the thickness of the resin film 42, the type of the first adhesive layer 41, the thickness of the first adhesive layer 41, and the moisture permeability of the first adhesive layer 41.

[0103] The thickness of the resin film 42 is, for example, 30 μm or more and 160 μm or less, preferably 30 μm or more and 120 μm or less, more preferably 30 μm or more and 80 μm or less, and still more preferably 50 μm or more and 80 μm or less.

[0104] The thickness of the first adhesive layer 41 is, for example, 100 μm or more and 900 μm or less, preferably 100 μm or more and 700 μm or less, more preferably 100 μm or more and 500 μm or less, and still more preferably 125 μm or more and 500 μm or less.

[0105] The moisture permeability of the first adhesive layer 41 is, for example, 100 g / (m 2 ·24 h) or more and 1000 g / (m 2 ·24 h) or less, preferably 100 g / (m 2 ·24 h) or more and 800 g / (m 2 ·24 h) or less, more preferably 100 g / (m 2 ·24 h) or more and 600 g / (m 2 ·24 h) or less, and still more preferably 200 g / (m 2 ·24 h) or more and 600 g / (m 2 ·24 h) or less.

[0106] <Second Adhesive Layer>

[0107] As the adhesive for forming the second adhesive layer 50, it can be appropriately selected and used from the above various adhesives in the same manner as the first adhesive layer 41. The second adhesive layer 50 can use a different type of adhesive from the first adhesive layer 41 or the same type of adhesive as the first adhesive layer 41. The thickness of the second adhesive layer 50 is not particularly limited and is, for example, about 1 to 100 μm, preferably about 2 to 50 μm.

[0108] <Image Display Unit>

[0109] As the image display unit 60, for example, a liquid crystal unit, an organic EL unit, etc. can be cited.

[0110] As the liquid crystal cell, for example, any one of a reflective liquid crystal cell using external light, a transmissive liquid crystal cell using light from a light source such as a backlight, and a transflective liquid crystal cell using both light from the outside and light from a light source can be used. When the liquid crystal cell is a liquid crystal cell using light from a light source, the image display device (liquid crystal display device) also has a polarizing plate disposed on the side opposite to the observation side of the image display unit (liquid crystal cell), and further has a light source. The polarizing plate on the light source side is preferably bonded to the liquid crystal cell via an appropriate adhesive layer. As a driving method of the liquid crystal cell, for example, any type of driving method such as VA mode, IPS mode, TN mode, STN mode, and bend alignment (π type) can be used.

[0111] As the organic EL cell, for example, an organic EL cell in which a light-emitting body (organic electroluminescent light-emitting body) is formed by sequentially laminating a transparent electrode, an organic light-emitting layer, and a metal electrode on a transparent substrate can be suitably used. The organic light-emitting layer is a laminate of various organic thin films. For example, a laminate including a hole injection layer containing a triphenylamine derivative and a light-emitting layer containing a fluorescent organic solid such as anthracene, a laminate of these light-emitting layers and an electron injection layer containing a perylene derivative, or a laminate of a hole injection layer, a light-emitting layer, and an electron injection layer can be used.

[0112] <Method for manufacturing an image display device>

[0113] The method for manufacturing an image display device includes a lamination step of obtaining a laminate in which a resin film 40 with a first adhesive layer, a polarizing plate 30, a second adhesive layer 50, and an image display unit 60 are sequentially laminated.

[0114] The method for manufacturing an image display device includes a heating step of heating a laminate in which a resin film 40 with a first adhesive layer, a polarizing plate 30, a second adhesive layer 50, and an image display unit 60 are sequentially laminated.

[0115] The method for manufacturing an image display device may further include other steps other than the steps described in the above embodiments. In the method for manufacturing an image display device, it is preferable that the heating step is the last step.

[0116] By performing the heating step, the moisture contained in the polarizing sheet 31, the first adhesive layer 41, the second adhesive layer 50, the first protective film 33, the second protective film 34, etc. can be reduced. By heating the above laminate, the moisture contained in each member (especially the polarizing sheet 31) constituting the laminate can be reduced during heating, and the transfer of moisture to each member (especially the polarizing sheet 31) constituting the laminate can be suppressed after the heating step.

[0117] The heating process is not particularly limited. For example, it can be carried out by putting the laminate into a hot air oven.

[0118] In the heating process of heating the laminate, the heating temperature is not particularly limited as long as it is a temperature that can reduce the moisture contained in each component (especially the polarizer 31) constituting the laminate as much as possible. For example, it is 80°C or higher and 100°C or lower, preferably 80°C or higher and 95°C or lower, and more preferably 85°C or higher and 95°C or lower.

[0119] In the heating process of heating the laminate, the heating time is not particularly limited as long as it is a time that can reduce the moisture contained in each component (especially the polarizer 31) constituting the laminate as much as possible. For example, it is 30 minutes or longer and 5 hours or shorter, preferably 1 hour or longer and 5 hours or shorter, and more preferably 1 hour or longer and 3 hours or shorter. It should be noted that the higher the above heating temperature, the shorter the heating time can be.

[0120] As a subsequent process using the image display device 20, for example, a process of attaching the front transparent member 70 can be cited. Figure 1 The image display device 10 with the front transparent member shown can be manufactured by peeling the resin film 42 from the image display device 20 and attaching the front transparent member 70 to the peeled first adhesive layer 41. It should be noted that until the resin film 42 is peeled from the image display device 20, the image display device 20 can be left standing at room temperature (25°C). By using the manufacturing method of the present invention, even if the period until the image display device 10 with the front transparent member is manufactured from the image display device 20 becomes long, the obtained image display device 10 with the front transparent member can have good durability when exposed to a high-temperature environment.

[0121] As the front transparent member 70, a front transparent plate (window layer), a touch panel, etc. can be cited. A transparent plate having appropriate mechanical strength and thickness can be used as the front transparent plate. For example, a transparent resin plate such as an acrylic resin or a polycarbonate resin, or a glass plate, etc. can be used as such a transparent plate. Various touch panels such as a resistive film method, a capacitive method, an optical method, an ultrasonic method, a glass plate or a transparent resin plate having a touch sensor function, etc. can be used as the touch panel.

[0122] <Use of the image display device or the image display device with the front transparent member>

[0123] As uses of the image display device 20 or the image display device 10 with a front transparent member, for example, uses in mobile devices such as televisions, personal computers, mobile phones, tablet terminals, etc., and vehicle-mounted uses can be cited. As a specific example of vehicle-mounted use, a navigation device, a speedometer, a touch panel for air conditioning, a rearview monitor, a backup monitor, etc. can be cited.

[0124] <Effect of the present embodiment>

[0125] For the image display device 20 obtained by the manufacturing method of the image display device using the present embodiment, the time until the polyene formation of the polyvinyl alcohol up to the polarizing plate 31 can be extended. Therefore, after the heating step, that is, after manufacturing the image display device 20, the progress of polyene formation due to reabsorption of water by the polarizing plate or the like can be suppressed during the period until the subsequent step is performed.

[0126] In addition, the high-temperature durability of the image display device 20 is excellent. Therefore, the image display device 10 with a front transparent member manufactured by the manufacturing method of the image display device using the present embodiment can also be suitably used for applications where there is a situation of being exposed to a high-temperature environment for a long time. For example, the image display device for vehicle-mounted use is exposed to a high-temperature environment for a long time. That is, the image display device 10 with a front transparent member can be suitably used for vehicle-mounted use.

[0127] Examples

[0128] Regarding the manufacturing method of the image display device and the manufacturing method of the image display device with a front transparent member, it will be further described in detail based on the examples described below. It should be noted that the manufacturing method of the image display device and the manufacturing method of the image display device with a front transparent member are not limited to the configurations described in the example column.

[0129] <Measurement of water vapor transmission rate of the protective film>

[0130] The water vapor transmission rate of the protective film used in the manufacture of the polarizing plate was measured at a temperature of 40 °C and a relative humidity of 90% according to the water vapor transmission test (cup method) of JIS Z0208.

[0131] <Measurement of water vapor transmission rate of the first adhesive layer>

[0132] The water vapor transmission rate of the first adhesive layer used in each production example was measured at a temperature of 40 °C and a relative humidity of 90% according to the water vapor transmission test (cup method) of JIS Z0208.

[0133] <Measurement of water permeation rate of the resin film with the first adhesive layer>

[0134] According to the water vapor transmission test (cup method) of JIS Z0208, the processed moisture permeable area is 28.26 cm2 The mass per unit area when the resin film with the first adhesive layer is placed in a moisture-permeable cup containing about 45 g of calcium chloride and left to stand in a constant-temperature machine at a temperature of 40°C and a relative humidity of 90% for 24 hours is defined as the "mass of the resin film with the first adhesive layer at 24 hours". In addition, the mass per unit area when left to stand in a constant-temperature machine at a temperature of 40°C and a relative humidity of 90% for 48 hours is defined as the "mass of the resin film with the first adhesive layer at 48 hours". Furthermore, the mass per unit area when left to stand in a constant-temperature machine at a temperature of 40°C and a relative humidity of 90% for 72 hours is defined as the "mass of the resin film with the first adhesive layer at 72 hours".

[0135] The moisture permeation rate (1) is obtained by the following formula (A), and the moisture permeation rate (2) is obtained by the following formula (B).

[0136] (Mass of the resin film with the first adhesive layer at 48 hours - Mass of the resin film with the first adhesive layer at 24 hours) / (m 2 ·24 hours) (A)

[0137] (Mass of the resin film with the first adhesive layer at 72 hours - Mass of the resin film with the first adhesive layer at 48 hours) / (m 2 ·24 hours) (B)

[0138] <Resin film with the first adhesive layer>

[0139] To produce a resin film with the first adhesive layer in which a resin film with a release layer and the first adhesive layer are laminated, the following resin film and the first adhesive layer are prepared.

[0140] 〔Resin film〕

[0141] · Resin film A1: A polyester-based resin film with a release layer having a thickness of 80 μm

[0142] · Resin film A2: A polyester-based resin film with a release layer having a thickness of 200 μm

[0143] · Resin film B1: A polyester-based resin film with a release layer having a thickness of 38 μm

[0144] · Resin film B2: A polyester-based resin film with a release layer having a thickness of 75 μm

[0145] 〔First adhesive layer〕

[0146] · Adhesive layer C1: A 500-μm adhesive layer is formed by laminating an adhesive layer with a thickness of 250 μm (trade name "CEF2810" manufactured by 3M). The moisture permeability is 216 g / (m 2 · 24 hours).

[0147] · Adhesive layer C2: An adhesive layer with a thickness of 250 μm (trade name "CEF2810" manufactured by 3M Company). The water vapor transmission rate is 364 g / (m 2 · 24 hours).

[0148] · Adhesive layer C3: An adhesive layer with a thickness of 125 μm (trade name "CEF2805" manufactured by 3M Company). The water vapor transmission rate is 548 g / (m 2 · 24 hours).

[0149] · Adhesive layer D: An acrylic adhesive layer with a thickness of 15 μm. The water vapor transmission rate is 2000 g / (m 2 · 24 hours) or more.

[0150] (Production Example 1: Production of a polarizing plate)

[0151] A polyvinyl alcohol-based resin film with a thickness of 30 μm was immersed in pure water at 21.5°C for 79 seconds (swelling process), and then immersed in an aqueous solution at 23°C with a mass ratio of potassium iodide / boric acid / water of 2 / 2 / 100 and containing 1.0 mM of iodine for 151 seconds (dyeing process). Thereafter, it was immersed in an aqueous solution at 68.5°C with a mass ratio of potassium iodide / boric acid / water of 2.5 / 4 / 100 for 76 seconds (first crosslinking process). Next, it was immersed in an aqueous solution at 45°C with a mass ratio of potassium iodide / boric acid / zinc chloride / water of 3 / 5.5 / 0.6 / 100 for 11 seconds (second crosslinking process, metal ion treatment process). Thereafter, it was immersed in a cleaning bath for cleaning (cleaning process) and dried at 38°C (drying process) to obtain a polarizing plate with a thickness of 12 μm in which iodine was adsorbed and oriented on polyvinyl alcohol. Stretching was mainly carried out during the dyeing process and the first crosslinking process, and the total stretching ratio was 5.85 times. It should be noted that the thickness of the obtained polarizing plate was measured using a digital micrometer "MH-15M" manufactured by Nikon Corporation.

[0152] (Production Example 2: Preparation of an adhesive composition)

[0153] 50 g of a modified polyvinyl alcohol-based resin containing acetoacetyl groups (manufactured by Mitsubishi Chemical Corporation: GOHSENX Z-410) was dissolved in 950 g of pure water, heated at 90°C for 2 hours, and then cooled to room temperature to obtain an acetoacetyl group-modified polyvinyl alcohol-based resin solution.

[0154] Maleic acid, a 40% by mass solution of glyoxal, and pure water were added to the obtained acetoacetyl group-modified polyvinyl alcohol-based resin solution so that their contents were as shown in Table 1 below to prepare an adhesive composition.

[0155] [Table 1]

[0156]

[0157] <Manufacture of Polarizing Plate>

[0158] Prepare the following protective films.

[0159] · Protective film F1: A saponified triacetyl cellulose film with a hard coat (trade name "40FJCHCN-LMP" manufactured by Toppan Printing Co., Ltd., triacetyl cellulose film thickness: 40 μm, hard coat thickness: 7 μm). The moisture permeability is 200 g / (m 2 · 24 hours).

[0160] · Protective film F2: A saponified cellulose acylate film (trade name "FUJITAC ZRG40" manufactured by Fujifilm Corporation, thickness 40 μm). The moisture permeability is 900 g / (m 2 · 24 hours).

[0161] · Protective film F3: A saponified triacetyl cellulose film with a hard coat (trade name "40FJCHCN-TC" manufactured by Toppan Printing Co., Ltd., triacetyl cellulose film thickness: 40 μm, hard coat thickness: 7 μm). The moisture permeability is 350 g / (m 2 · 24 hours).

[0162] · Protective film F4: A saponified triacetyl cellulose film (trade name "TJ40UL" manufactured by Fujifilm Corporation, thickness 40 μm). The moisture permeability is 900 g / (m 2 · 24 hours).

[0163] · Protective film F5: A saponified cellulose acylate film (trade name "FUJITAC ZRG25" manufactured by Fujifilm Corporation, thickness 25 μm). The moisture permeability is 1200 g / (m 2 · 24 hours).

[0164] (Production Example 3: Production of Polarizing Plate (1))

[0165] On one side of the polarizing film manufactured in Production Example 1, the surface of the protective film F1 without the laminated hard coat is laminated via the adhesive composition prepared in Production Example 2. In addition, on the other side of the polarizing film, the protective film F2 is laminated via the adhesive composition prepared in Production Example 2 and bonded using a roll laminator. Thereafter, it is dried at 75 °C for 8 minutes to obtain the polarizing plate (1). It should be noted that the dried thickness of the adhesive layer formed by the adhesive composition is 80 nm respectively. The protective film F1 corresponds to the first protective film. The protective film F2 corresponds to the second protective film. Table 2 shows the constitution of the polarizing plate (1).

[0166] (Production Example 4: Production of Polarizing Plate (2))

[0167] Except for using protective film F3 instead of protective film F1, the same operations as those for polarizing plate (1) were performed to obtain polarizing plate (2). The composition of polarizing plate (2) is shown in Table 2.

[0168] (Production Example 5: Production of Polarizing Plate (3))

[0169] Except for using protective film F4 instead of protective film F1, the same operations as those for polarizing plate (1) were performed to obtain polarizing plate (3). It should be noted that protective film F4 is adhered to the polarizing film via an adhesive layer on the triacetyl cellulose side. The composition of polarizing plate (3) is shown in Table 2.

[0170] (Production Example 6: Production of Polarizing Plate (4))

[0171] Except for using protective film F5 instead of protective film F2, the same operations as those for polarizing plate (1) were performed to obtain polarizing plate (4). The composition of polarizing plate (4) is shown in Table 2.

[0172] [Table 2]

[0173]

[0174] (Production Example 6: Production of Laminate (1))

[0175] On the second protective film side of polarizing plate (1), that is, on the protective film F2 side, an acrylic adhesive layer with a thickness of 25 μm was formed to obtain a polarizing plate (1) with an adhesive layer. In the obtained polarizing plate (1) with an adhesive layer, it was cut into a size of 90 mm × 100 mm such that the absorption axis was parallel to the long side. A 100 mm × 100 mm alkali-free glass ("EAGLE XG" manufactured by CORNING) was adhered to the surface of the adhesive layer of the polarizing plate (1) with an adhesive layer to obtain a polarizing plate (1) with a glass plate.

[0176] On the first protective film side of the obtained polarizing plate with a glass plate, that is, on the protective film F1 side, a resin film with a first adhesive layer laminated with an adhesive layer C1 with a thickness of 500 μm and a resin film A1 with a thickness of 80 μm having a release layer was adhered with the adhesive layer side to produce laminate (1).

[0177] (Production Example 7: Production of Laminate (2))

[0178] Except for changing the thickness of the first adhesive layer (adhesive layer C1) of the resin film with the first adhesive layer from 500 μm to the first adhesive layer (adhesive layer C2) with a thickness of 250 μm, the operation was the same as in Production Example 6 to produce a laminate (2).

[0179] (Production Example 8: Production of laminate (3))

[0180] Except for changing the thickness of the first adhesive layer (adhesive layer C1) of the resin film with the first adhesive layer from 500 μm to the first adhesive layer (adhesive layer C3) with a thickness of 125 μm, the operation was the same as in Production Example 6 to produce a laminate (3).

[0181] (Production Example 9: Production of laminate (4))

[0182] Except for changing the polarizing plate (1) to the polarizing plate (2), the operation was the same as in Production Example 7 to produce a laminate (4).

[0183] (Production Example 10: Production of laminate (5))

[0184] Except for changing the polarizing plate (1) to the polarizing plate (3), the operation was the same as in Production Example 7 to produce a laminate (5).

[0185] (Production Example 11: Production of laminate (6))

[0186] Except for changing the polarizing plate (1) to the polarizing plate (4), the operation was the same as in Production Example 7 to produce a laminate (6).

[0187] (Production Example 12: Production of laminate (7))

[0188] Except for changing the resin film (resin film A1) with a thickness of 80 μm of the resin film with the first adhesive layer to a polyester-based resin film (resin film A2) with a thickness of 200 μm having a release layer, the operation was the same as in Production Example 7 to produce a laminate (7).

[0189] (Production Example 13: Production of laminate (8))

[0190] Except for not laminating the polyester-based resin film (resin film A1) with a thickness of 80 μm having a release layer, the operation was the same as in Production Example 7 to produce a laminate (8). That is, in the laminate (8), the first adhesive layer (adhesive layer C2) with a thickness of 250 μm was exposed.

[0191] (Production Example 14: Production of laminate (9))

[0192] A laminate (9) was produced in the same manner as in Production Example 6, except that a resin film with an adhesive layer having a thickness of 53 μm, in which an acrylic adhesive layer (adhesive layer D) with a thickness of 15 μm and a polyester resin film (resin film B1) with a thickness of 38 μm were laminated in place of the resin film with the first adhesive layer.

[0193] (Production Example 15: Production of laminate (10))

[0194] A laminate (10) was produced in the same manner as in Production Example 6, except that a resin film with an adhesive layer having a thickness of 90 μm, in which an acrylic adhesive layer (adhesive layer D) with a thickness of 15 μm and a polyester resin film (resin film B2) with a thickness of 75 μm were laminated in place of the resin film with the first adhesive layer.

[0195] (Example 1: Production of simulated image display device (1))

[0196] The laminate (1) obtained in Production Example 6 was heated at 95 °C for 3 hours (heating step) to produce a simulated image display device (1) for evaluation. Table 3 shows the constitution of the laminate (1) and the method of the heating step of Example 1. It should be noted that "integral" described in the heating step column of Table 3 means heating in the state where the resin film with the first adhesive layer is laminated on the polarizing plate as the laminate, and means using the heated laminate as the simulated image display device.

[0197] It should be noted that a simulated image display device means an evaluation laminate in which a glass plate is laminated in place of the image display unit of an image display device.

[0198] [Production of evaluation sample (simulated image display device with front transparent member)]

[0199] The simulated image display device (1) obtained in Example 1 was allowed to stand in an environment of 23 °C and 60% relative humidity for 1 hour. After standing, an 80-μm polyester resin film (resin film A1) was peeled off, and an alkali-free glass ("EAGLE XG" manufactured by CORNING) was adhered to the exposed 500-μm adhesive layer (adhesive layer C1), and autoclave treatment was carried out at a temperature of 50 °C and a pressure of 5 kgf / cm 2 (490.3 kPa) for 15 minutes. This was used as the evaluation sample (1-1) (simulated image display device (1-1) with front transparent member).

[0200] It should be noted that a simulated image display device with a front panel means an evaluation laminate in which a glass plate is laminated in place of the image display unit of an image display device with a front panel.

[0201] The simulated image display device (1) obtained in Example 1 was left standing in an environment of 23°C and 60% relative humidity. Except that the standing times were changed to 6 hours, 24 hours, 36 hours, 72 hours, 96 hours, and 120 hours respectively, the same operations as those for the above evaluation sample (1-1) were performed to further produce the following 6 evaluation samples. It should be noted that the evaluation sample with a standing time of 6 hours was designated as evaluation sample (1-6), the evaluation sample with a standing time of 24 hours was designated as evaluation sample (1-24), the evaluation sample with a standing time of 36 hours was designated as evaluation sample (1-36), the evaluation sample with a standing time of 72 hours was designated as evaluation sample (1-72), the evaluation sample with a standing time of 96 hours was designated as evaluation sample (1-96), and the evaluation sample with a standing time of 120 hours was designated as evaluation sample (1-120).

[0202] (Examples 2 to 6: Fabrication of Simulated Image Display Devices (2) to (6))

[0203] The laminates (2) to (6) were each heated at 95°C for 3 hours (heating process) to fabricate the simulated image display devices (2) to (6). Table 3 shows the compositions of the laminates (2) to (6) and the methods of the heating processes in Examples 2 to 6.

[0204] In the same manner as for the simulated image display device (1), 7 evaluation samples with standing times of 1 hour, 6 hours, 24 hours, 36 hours, 72 hours, 96 hours, and 120 hours were respectively fabricated for the simulated image display devices (2) to (6).

[0205] (Comparative Example 1: Fabrication of Simulated Image Display Device (7))

[0206] The laminate (7) was heated at 95°C for 3 hours (heating process) to fabricate the simulated image display device (7). Except that the simulated image display device (1) was changed to the simulated image display device (7), the same operations as above were performed to fabricate 7 evaluation samples. Table 3 shows the composition of the laminate (7) and the method of the heating process in Comparative Example 1.

[0207] (Comparative Example 2: Fabrication of Simulated Image Display Device (8))

[0208] The laminate (8) was heated at 95°C for 3 hours (heating process) to fabricate the simulated image display device (8). Table 3 shows the composition of the laminate (8) and the method of the heating process in Comparative Example 2.

[0209] After allowing the obtained simulated image display device (8) to stand in an environment of 23°C and 60% relative humidity, an alkali-free glass ("EAGLE XG" manufactured by CORNING) was bonded to the exposed first adhesive layer (adhesive layer C2) with a thickness of 250 μm, and this was used as an evaluation sample. Other than this, the operation was the same as that for the simulated image display device (1), and seven types of evaluation samples were produced.

[0210] (Comparative Example 3: Production of simulated image display device (9))

[0211] Prepare the following adhesive sheet (1). A polyester resin film (resin film A1) with a thickness of 80 μm having a release layer was laminated on both sides of an adhesive layer (adhesive layer C2) with a thickness of 250 μm, thereby obtaining an adhesive sheet (1) having a structure of polyester resin film / adhesive layer / polyester resin film.

[0212] The adhesive sheet (1) and the laminate (9) were each heated separately at 95°C for 3 hours. The resin film with the first adhesive layer of the heated laminate (9) was peeled off together with the adhesive layer, thereby exposing the first protective film. In addition, the polyester resin film on one surface of the adhesive sheet (1) was peeled off, and the adhesive layer side of the adhesive sheet was bonded to the first protective film of the laminate (9) to obtain a simulated image display device (9). Table 3 shows the structure of the laminate (9) and the method of the heating process in Comparative Example 3. It should be noted that the "separately" described in the heating process column of Table 3 means that the laminate and the adhesive sheet (1) were heated separately as described above, and it means that a simulated image display device was obtained by bonding the adhesive layer of the adhesive sheet (1) to the exposed polarizing plate after heating.

[0213] After allowing the obtained simulated image display device (9) to stand in an environment of 23°C and 60% relative humidity, the release film on the other surface of the adhesive sheet (1) was peeled off from the simulated image display device (9), and an alkali-free glass ("EAGLE XG" manufactured by CORNING) was bonded to the surface of the 250-μm adhesive layer. Other than this, the operation was the same as that for the simulated image display device (1), and seven types of evaluation samples were produced.

[0214] (Comparative Example 4: Production of simulated image display device (10))

[0215] Except that the laminate (8) was changed to the laminate (10), the operation was the same as that in Comparative Example 3 to produce a simulated image display device (10) and its evaluation samples (seven types). Table 3 shows the structure of the laminate (10) and the method of the heating process in Comparative Example 4.

[0216] (Comparative Example 5: Production of simulated image display device (11))

[0217] The step of heating at 95°C for 3 hours is omitted for the laminate (2), and thus the analog image display device (11) is produced. Except for changing the analog image display device (1) to the analog image display device (11), the same operations as above are performed to produce 7 kinds of evaluation samples.

[0218] <Evaluation of Initial Optical Characteristics>

[0219] For the 7 kinds of evaluation samples of the analog image display device (1) with a front panel obtained in Example 1, the monomer transmittance is measured using a spectrophotometer / color difference meter (Konica Minolta, Inc. “CM-3700A”). Using the initial value of the monomer transmittance and the isochromatic function of the C light source for the obtained monomer transmittance, L a b The chromaticity in the (CIE) color system is obtained, and thus the monomer hue b value is obtained. Here, the reference value of the monomer hue b value is set to 6.0 or less. For the evaluation samples with a value higher than the reference value, it is determined that the optical characteristics deteriorate due to the heating process, that is, it is determined that the form is not suitable for the heating process and is excluded from the high-temperature durability evaluation described later. The transmittance of the evaluation samples is measured at wavelengths of 380 to 780 nm.

[0220] The visibility-corrected monomer transmittance (Ty) is obtained by performing visibility correction on the obtained monomer transmittance using a 2-degree field of view (C light source) of JIS Z 8701:1999 “Methods of Representing Colors - XYZ Color System and X10Y10Z10 Color System”.

[0221] <High-Temperature Durability Evaluation>

[0222] After the initial optical characteristics of the 7 kinds of evaluation samples of the analog image display device (1) are evaluated respectively, they are left standing in an environment at a temperature of 105°C for 500 hours. The visibility-corrected monomer transmittance of each evaluation sample after standing is measured.

[0223] After the measurement, the change amount of the visibility-corrected monomer transmittance of each evaluation sample defined by the following formula (C) is obtained.

[0224] Formula (C): (Visibility-corrected monomer transmittance before standing) - (Visibility-corrected monomer transmittance after standing)

[0225] First, select the evaluation samples with the absolute value of the change in the visible light transmittance of the monomer for visibility correction being less than 3% from the evaluation samples (1-1), evaluation samples (1-6), evaluation samples (1-24), evaluation samples (1-36), evaluation samples (1-72), evaluation samples (1-96), and evaluation samples (1-120). Subsequently, among the evaluation samples with the absolute value of the change in the visible light transmittance of the monomer for visibility correction being less than 3%, select the evaluation sample with the longest standing time in an environment of 23°C and 60% relative humidity when the evaluation sample was prepared. Take the standing time in an environment of 23°C and 60% relative humidity when the evaluation sample was prepared as the "maximum time without polyene formation" in Table 3. Sometimes, the "maximum time without polyene formation" is also simply referred to as the "maximum time" below.

[0226] The respective evaluation samples of the analog image display devices (2)-(6), (8)-(11) with front panels were evaluated in the same manner. It should be noted that for the analog image display device (7) with a front panel in Comparative Example 1, since the above-mentioned monomer hue b value was higher than the reference value, the high-temperature durability evaluation was not performed. The maximum time in Comparative Example 1 in Table 3 was set to "-". It should be noted that in Comparative Example 5, since the absolute value of the change in the visible light transmittance of the monomer for visibility correction was 3% or more for all 7 types of evaluation samples, it was determined that polyene formation had occurred in less than 1 hour. Therefore, Comparative Example 5 was recorded as "<1".

[0227] [Table 3]

[0228]

[0229] In Examples 1 to 6, it was confirmed that the maximum time was longer than that in Comparative Examples 1 to 5. That is, it was confirmed that even if time was left until the subsequent process after the heating process, polyene formation was not likely to occur. Generally, after the heat treatment of the laminate as an intermediate, it sometimes takes about 24 to 48 hours until the subsequent process of bonding the front transparent member is performed. The maximum times in Examples 1 to 5 were all longer than 48 hours. Therefore, it is possible to appropriately ensure the time until the subsequent process is performed.

[0230] In Examples 2, 4, 5, and 6, the resin film with the first adhesive layer had the same composition. On the other hand, in Examples 2, 4, 5, and 6, polarizing plates (1), (2), (3), and (4) were used respectively, which was different in this regard. In such Examples 2, 4, 5, and 6, it was confirmed that the maximum time in Example 2 was the longest, the maximum times in Examples 4 and 6 were the second longest, and the maximum time in Example 5 was the second longest.

[0231] Based on Examples 2, 4, 5, and 6, it can be considered as follows. The lower the moisture permeability of the first protective film, the more effectively the transfer of moisture to the polarizer after the heating process can be suppressed, and thus the maximum time without polyene formation can be extended.

[0232] In Comparative Example 1, the moisture permeation rate (1) of the resin film with the first adhesive layer is less than a specific range, and the moisture permeation rate (2) is less than a specific range. Therefore, although the polarizing plate (1) is used in the same manner as in Examples 1 to 3, it is expected that moisture is not easily discharged during the heating process, and it can be considered that the optical properties deteriorate due to the heating process.

[0233] In Comparative Example 2, the moisture permeation rate (1) and the moisture permeation rate (2) are greater than a specific range. Therefore, it can be considered that the polarizer of the image display device after the heating process is likely to absorb moisture, and it can be considered that polyene formation of the polyvinyl alcohol-based resin forming the polarizer is likely to proceed.

[0234] In Comparative Examples 3 and 4, although the laminate is heated, the laminate having the polarizing plate and the resin film with the adhesive layer are heated separately, and then the resin film with the adhesive layer is bonded to the polarizing plate. This is different from Example 2 in this regard. It can be considered that during the period from after heating until the resin film with the adhesive layer is bonded to the exposed first protective film, moisture is absorbed through the first protective film, and thus polyene formation is likely to proceed.

[0235] In Comparative Example 5, the heating process is not performed, and the moisture contained in the polarizer cannot be reduced. Therefore, it can be considered that polyene formation of the polyvinyl alcohol-based resin forming the polarizer is likely to proceed.

[0236] Explanation of Reference Numerals

[0237] 10 Image display device with a front transparent member, 20 Image display device, 30 Polarizing plate, 31 Polarizer, 32 Adhesive layer, 33 First protective film, 34 Second protective film, 40 Resin film with a first adhesive layer, 41 First adhesive layer, 42 Resin film, 50 Second adhesive layer, 60 Image display unit, 70 Front transparent member.

Claims

1. A method for manufacturing an image display device, comprising laminating a resin film having a first adhesive layer, a polarizing plate having a polarizer formed of a polyvinyl alcohol-based resin film, a second adhesive layer, and an image display unit in this order, The manufacturing method comprises: a step of heating a laminated body in which the resin film with the first adhesive layer, the polarizing plate, the second adhesive layer, and the image display unit are sequentially laminated; In the resin film with the first adhesive layer, the resin film is laminated in direct contact with the first adhesive layer. The water permeation rate (1) of the resin film with the first adhesive layer determined by the following formula (A) is 5 g / (m 2 ·24 hours) or more and 20g / (m 2 24 hours) or less, The water permeation rate (2) of the resin film with the first adhesive layer determined by the following formula (B) is 10 g / (m 2 24 hours) or more, The first adhesive layer side of the resin film with the first adhesive layer of the laminate is laminated on the polarizing plate side, (Mass of the resin film with the first adhesive layer at 48 hours - Mass of the resin film with the first adhesive layer at 24 hours) / (m 2 ·24 hours) Formula (A) (mass of the resin film with the first adhesive layer at 72 hours - mass of the resin film with the first adhesive layer at 48 hours) / (m 2 ·24 hours) Formula (B) It should be noted that the mass of the resin film with the first adhesive layer at 24 hours in the formula (A) and the formula (B) refers to the mass of the resin film with the first adhesive layer processed to a moisture permeability area of ​​28.26 cm according to the moisture permeability test of JIS Z0208. 2 The mass per unit area of ​​the resin film with the first adhesive layer is placed in a moisture permeable cup to which about 45 g of calcium chloride is added and placed in a thermostat at a temperature of 40°C and a relative humidity of 90% for 24 hours. The mass of the resin film with the first adhesive layer at 48 hours means the mass of the resin film with the first adhesive layer processed to a moisture permeable area of ​​28.26 cm according to the moisture permeability test of JIS Z0208. 2 The mass per unit area of ​​the resin film with the first adhesive layer is placed in a moisture permeable cup to which about 45 g of calcium chloride is added and placed in a constant temperature machine at a temperature of 40°C and a relative humidity of 90% for 48 hours. The mass of the resin film with the first adhesive layer at 72 hours refers to the mass of the resin film processed to a moisture permeability area of ​​28.26 cm according to the moisture permeability test of JIS Z0208. 2 The mass per unit area of ​​the resin film with the first adhesive layer is placed in a moisture permeable cup to which about 45 g of calcium chloride is added and left to stand in a constant temperature machine at a temperature of 40° C. and a relative humidity of 90% for 72 hours.

2. The method for manufacturing an image display device according to claim 1, wherein: The water permeation rate (2) of the resin film with the first adhesive layer is 40 g / (m 2 · 24 hours) or less.

3. The method for manufacturing an image display device according to claim 1, wherein: The water permeation rate (1) of the resin film with the first adhesive layer is 5 g / (m 2 24 hours) or more and 15g / (m 2 24 hours) or less, The water permeation rate (2) of the resin film with the first adhesive layer is 10 g / (m 2 ·24 hours) or more and 25g / (m 2 · 24 hours) or less.

4. The method for manufacturing an image display device according to any one of claims 1 to 3, characterized in that: The value of the water permeation rate (2) of the resin film with the first adhesive layer is greater than the value of the water permeation rate (1) of the resin film with the first adhesive layer.

5. The method for manufacturing an image display device according to any one of claims 1 to 3, wherein: The polarizing plate comprises the polarizer and a protective film, wherein the protective film is laminated on the surface of the polarizer on the first pressure-sensitive adhesive layer side via an adhesive layer. The moisture permeability of the protective film at a temperature of 40°C and a relative humidity of 90% is 1000 (g / m 2 · 24 hours) or less.

6. A method for manufacturing an image display device with a front transparent member, the method comprising: A step of peeling off the resin film from the image display device obtained by the method for producing an image display device according to claim 1 and bonding a front transparent member to the first adhesive layer.

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