WO2022219838A1 - Method for producing optical laminate - Google Patents

Abstract

[Problem] To provide a method for producing an optical laminate, the method enabling curling to be suppressed. [Solution] The method for producing an optical laminate 100 according to the present invention includes: a separator affixation step ST3 for affixing a long, band-form separator 4 to a long, band-form polarizing plate 10 via an adhesive agent layer 3 formed on the separator 4; a surface-protective film affixation step ST5 after the separator affixation step, the surface-protective film affixation step involving affixing a long, band-form surface-protective film 5 to the polarizing plate; and a first separator detachment/affixation step ST6 after the surface-protective film affixation step, the first separator detachment/affixation step involving detaching the long, band-form separator from the adhesive agent layer and then affixing the long, band-form separator to the polarizing plate via the adhesive agent layer.

Description

Method for manufacturing optical laminate

The present invention relates to a method for manufacturing an optical laminate including at least a polarizing plate, a separator and a surface protective film. In particular, the present invention relates to a method for manufacturing an optical layered body capable of suppressing curling.

Conventionally, polarizing plates have been used as constituent materials for liquid crystal display devices, organic EL display devices, and the like. The polarizing plate includes a polarizing film and a retardation film or the like depending on the application. A polarizing film is composed of, for example, a polarizer dyed with a dichroic substance such as iodine and a protective film for protecting the polarizer. A long belt-shaped polarizing film is produced by bonding a long belt-shaped protective film to at least one surface of a long belt-shaped polarizer. A long belt-like retardation film or the like is attached to one side of the manufactured long belt-like polarizing film to manufacture a long belt-like polarizing plate. A long strip-shaped separator (release film) is attached to one side of the produced long strip-shaped polarizing plate, and a long strip-shaped surface protective film is stuck to the other side to form a long A strip-shaped optical laminate is produced. These long belt-like films are usually laminated by a roll-to-roll method or a roll-to-sheet method. The manufactured long strip-shaped optical layered body is cut into a size and shape according to the application, and used for a liquid crystal display device or the like. When used in a liquid crystal display device or the like, the separator is peeled off and the remaining components of the optical layered body are attached to the liquid crystal display device or the like.

FIG. 8 is a flowchart showing a schematic process example of a conventional method for manufacturing an optical layered body. As shown in FIG. 8, the conventional method for manufacturing an optical laminate includes a polarizing film manufacturing process ST1′, a retardation film bonding process ST2′, a separator bonding process ST3′, an inspection process ST4′, and a surface protective film bonding. It includes step ST5'.
In the polarizing film manufacturing step ST1′, a long belt-shaped resin film is used as a raw film, and this raw film is immersed in various treatment baths while being transported in the longitudinal direction, and various treatments such as dyeing and stretching are performed. to produce a long band-shaped polarizer. Then, a long belt-shaped polarizing film is manufactured by bonding a long belt-shaped protective film to at least one surface of the long belt-shaped polarizer.
In the retardation film bonding step ST2′, a long belt-like retardation film (such as a half-wave plate or a quarter-wave plate) is bonded to one side of a long belt-like polarizing film to form a long belt-like film. Manufacture polarizing plates.

In the separator bonding step ST3′, an adhesive is applied while conveying the long belt-shaped separator in the longitudinal direction, and the applied adhesive is cured by heating and drying in an oven or the like to form an adhesive layer. do. Then, by laminating the adhesive layer side of the long strip-shaped separator (separator with adhesive layer) to one side of the long strip-shaped polarizing plate, a long strip in which the polarizing plate, the adhesive layer, and the separator are laminated is obtained. A strip-shaped intermediate is produced.
In the inspection step ST4', the polarizing plate is inspected by peeling off only the separator while leaving the adhesive layer interposed between the separator and the polarizing plate on the polarizing plate side. Examples of inspection methods for the polarizing plate include transmission inspection, crossed Nicols inspection, reflection inspection, and the like. In the inspection step ST4′, after the polarizing plate is inspected, the peeled separator is attached to the polarizing plate again to restore the original state of the intermediate.

In the surface protective film bonding step ST5', a long belt-shaped surface protective film is bonded to the surface of the long belt-shaped polarizing plate opposite to the side where the separator is bonded.
Through the polarizing film manufacturing step ST1' to the surface protection film bonding step ST5' described above, a long strip-shaped optical layered body is manufactured.

However, in the optical layered body manufactured as described above, the optical layered body after being cut into the product size may curl (warp at the edge), which poses a problem in use.
For example, Patent Document 1 proposes to use a specific material for the protective film that protects the polarizer as a method for suppressing curling of the polarizing film. , not generic. There is a demand for a method capable of suppressing curling without particularly changing the materials of constituent elements of conventionally used optical laminates.

JP 2007-256568 A

The present invention has been made to solve the problems of the prior art, and an object of the present invention is to provide a method for manufacturing an optical laminate capable of suppressing curling.

In order to solve the above-mentioned problems, the inventors of the present invention conducted extensive studies and found that the formation of the pressure-sensitive adhesive layer on the separator in the separator bonding step (ST3′ in FIG. 8) of the conventional method for producing an optical layered body is It has been found that it may be one of the causes of body curling. Specifically, when the pressure-sensitive adhesive applied to the separator is heated and dried, the separator shrinks, and it is thought that unevenness occurs in the thickness direction. When the separator is bonded to the polarizing plate in the separator bonding step, or when the separator is bonded to the polarizing plate again in the inspection step (ST4′ in FIG. 8), unevenness generated on the separator due to heating is smoothed out. It is thought that although the optical laminate is stuck together in a state of being stretched, a force tends to return the separator to the contracted state as time elapses after the adhesion, and this causes the optical laminate to curl.
The inventors of the present invention focused on the cause of the occurrence of the above and conducted further intensive studies. ') is effective in suppressing curling. That is, since the laminate to which the surface protective film is attached has higher rigidity than the laminate before the surface protective film is attached, the separator in which the unevenness is extended to the highly rigid laminate It has been found that if the separator is stuck together, curling is less likely to occur even if a force acts to return the separator to the contracted state.
The present invention has been completed based on the above findings of the present inventors.

That is, in order to solve the above problems, the present invention provides a separator lamination step of laminating the separator to a long strip-shaped polarizing plate via an adhesive layer formed on the long strip-shaped separator, and the separator lamination step. After the step, a surface protective film laminating step of laminating a long strip-shaped surface protective film to the polarizing plate, and after the surface protective film laminating step, after peeling the long strip-shaped separator from the adhesive layer and a first separator peeling/bonding step of bonding a long belt-shaped separator to the polarizing plate via the pressure-sensitive adhesive layer.

In the first separator peeling/bonding step of the present invention, the peeled separator and the separator to be bonded may be the same separator or different separators. That is, in the first separator peeling and bonding step of the present invention, the separator is peeled from the adhesive layer (only the separator is peeled while the adhesive layer remains on the polarizing plate), and then the same separator is peeled off the adhesive layer. It includes the case of re-bonding to the polarizing plate via. In addition, in the first separator peeling/bonding step, a new separator different from the peeled separator (that is, a separator that is less likely to have unevenness because it is not heated for forming the adhesive layer) is applied to the adhesive layer. It also includes the case of pasting (re-pasting) to the polarizing plate via.
According to the present invention, by including the first separator peeling/bonding step, separator peeling and separator bonding are performed. In other words, even if the separator to be bonded is the same as the separator to be peeled off, the separator is bonded to the polarizing plate in a state in which the unevenness of the separator is extended. Since the first separator peeling/bonding process is performed after the surface protective film bonding process, the separator having the unevenness extended is bonded to the highly rigid laminate, and the separator is in a contracted state. Curling can be suppressed even if a force that tries to return is applied.

The separator laminating step includes, for example, an adhesive layer forming step of applying an adhesive to a long belt-shaped separator and heating and curing the applied adhesive to form the adhesive layer.

Preferably, in the present invention, after peeling a long strip-shaped separator from the adhesive layer before the step of bonding the surface protective film, the long strip-shaped separator is attached to the polarizing plate through the adhesive layer. A second separator peeling/bonding step of bonding is included.
In the second separator peeling/bonding step, as in the first separator peeling/bonding step, the separated separator and the separator to be bonded may be the same separator or different separators. good.
According to the preferred method described above, the separation of the separator and the lamination of the separator are performed not only after the step of attaching the surface protective film, but also before the step of attaching the surface protective film. In other words, even if the separator to be bonded is the same as the separator to be peeled off, the separator is bonded to the polarizing plate in a state in which the unevenness of the separator is extended, so curling can be further suppressed. be.

Preferably, the second separator peeling/bonding step also serves as an inspection step of inspecting the polarizing plate after peeling the long strip-shaped separator.
According to the preferred method described above, since the second separator peeling/bonding step also serves as the inspection step for the polarizing plate, compared to the case where the second separator peeling/bonding step and the inspection step are provided separately, the manufacturing process has the advantage of being simple.

Preferably, in the first separator peeling/bonding step, the time from peeling the long strip-shaped separator to sticking the long strip-shaped separator is one minute or less.
According to the above preferable method, the time from peeling off the long strip separator to sticking the long strip separator, in other words, the time for the adhesive layer to be exposed is short. Therefore, even if the humidity in the first separator peeling/bonding step changes due to, for example, seasonal effects or daytime or nighttime effects, the polarizing plate absorbs moisture in the atmosphere from the pressure-sensitive adhesive layer side. It is possible to suppress variations in curling that occur due to swelling due to pressure.
In the case where the present invention includes the second separator peeling/bonding step, the long strip-shaped separator is peeled off and then the long strip-shaped separator is similarly removed in the second separator peeling/bonding step. It is preferable that the time until bonding is within 1 minute.

Preferably, in the first separator peeling/bonding step, a long belt-shaped separator and the polarizing plate are bonded together by a bonding roller, and the separator enters the bonding roller at an angle of less than 90°. , the angle of entry of the polarizing plate into the bonding roller is less than 90°.

In the preferred method described above, the "advance angle of the separator to the laminating roller" is perpendicular to a straight line passing through the rotation center of a pair of opposing rollers constituting the laminating roller, and is directed toward the exit side of the laminating roller. It means the angle between the vector and the vector indicating the traveling direction of the separator until it contacts the laminating roller. Similarly, the "approaching angle of the polarizing plate to the bonding roller" is a vector perpendicular to a straight line passing through the rotation center of a pair of rollers constituting the bonding roller and directed to the output side of the bonding roller. It means the angle formed with the vector indicating the traveling direction of the polarizing plate until it comes into contact with the joining roller.
According to the findings of the present inventors, when the separator enters the bonding roller at a large angle (90° or more), the TD direction direction) and negative curl (curl that makes the side where the separator is positioned concave) increases, and the angle of entry of the polarizing plate into the laminating roller is large (90° or more), curl in the TD direction. In addition, plus curl (curl that becomes convex on the side where the separator is located) increases.
According to the preferred method described above, curling can be further suppressed by setting both the entrance angles of the separator and the polarizing plate to the bonding rollers to less than 90°.
When the present invention includes the second separator peeling/bonding step, the long strip-shaped separator and the polarizing plate are similarly bonded by a bonding roller in the second separator peeling/bonding step. In addition, it is preferable that the angle at which the separator enters the bonding roller is less than 90°, and the angle at which the polarizing plate enters the bonding roller is less than 90°.

Preferably, the bonding roller includes a first roller that contacts the separator and a second roller that contacts the polarizing plate, and one of the first roller and the second roller has a resin surface. and the other surface is made of metal.
When both the surface of the first roller and the surface of the second roller are made of metal, when the separator and the polarizing plate are bonded together, the interface between the separator and the polarizing plate (the interface between the separator and the adhesive layer) ) may generate air bubbles. If both the surface of the first roller and the surface of the second roller are made of resin, the separator may wrinkle.
According to the preferred method described above, one surface of the first roller and the second roller is made of resin and the other surface is made of metal, thereby suppressing the possibility of air bubbles or wrinkles. be.
In addition, when the present invention includes a second separator peeling/bonding step, the bonding roller is the first roller that contacts the separator, and It is preferable that one surface of the first roller and the second roller is made of resin and the other surface is made of metal.

Preferably, the first roller has a metal surface, and the second roller has a resin surface.
According to the preferred method described above, in addition to being able to suppress the possibility of generating air bubbles and wrinkles, the surface of the second roller in contact with the polarizing plate is made of resin (not made of metal). Therefore, it is possible to suppress appearance defects such as scratches and dents on the polarizing plate.
When the present invention includes the second separator peeling/bonding step, the surface of the first roller is made of metal, and the second separator peeling/bonding step is also performed in the same manner. It is preferable that the surface of the roller is made of resin.

According to the present invention, it is possible to effectively suppress curling without particularly changing the materials of the constituent elements of conventionally used optical laminates.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows typically schematic structure of the optical laminated body manufactured by the manufacturing method which concerns on one Embodiment of this invention. 1 is a flow diagram showing schematic steps of a method for manufacturing an optical layered body according to an embodiment of the present invention; FIG. FIG. 3 is a side view (viewed from a horizontal direction perpendicular to the conveying direction of each film) schematically showing an example of the schematic configuration of an apparatus that performs an inspection step ST4 shown in FIG. 2 ; FIG. 3 is a side view (viewed from a horizontal direction perpendicular to the conveying direction of each film) schematically showing an example of the schematic configuration of an apparatus that performs the first separator peeling/bonding step ST6 shown in FIG. 2 ; It is explanatory drawing explaining bonding of the 3rd intermediate M3 and the separator 4b by the bonding roller R7 shown in FIG. FIG. 3 is a side view (viewed from a horizontal direction perpendicular to the conveying direction of each film) schematically showing an example of the schematic configuration of an apparatus for performing a modification of the first separator peeling/bonding step ST6 shown in FIG. . It is explanatory drawing explaining the curl evaluation method. FIG. 2 is a flowchart showing an example of schematic steps of a conventional method for manufacturing an optical layered body.

A method for manufacturing an optical layered body according to an embodiment of the present invention will be described below with reference to the accompanying drawings as appropriate. It should be noted that each drawing is for reference only, and that the dimensions, scales and shapes of the components of the optical layered body and device shown in each drawing may differ from the actual ones. Please note.

<Structure of Optical Laminate>
First, the configuration of the optical layered body manufactured by the manufacturing method according to the present embodiment will be described.
FIG. 1 is a cross-sectional view schematically showing a schematic configuration of an optical layered body manufactured by a manufacturing method according to this embodiment.
As shown in FIG. 1, the optical laminate 100 of this embodiment includes a polarizing film 1, a retardation film 2, an adhesive layer 3, a separator 4, and a surface protective film 5. A laminate of the polarizing film 1 and the retardation film 2 constitutes the polarizing plate 10 . A laminate of the polarizing plate 10 and the adhesive layer 3 constitutes the first intermediate M1. A laminate of the first intermediate M1 and the separator 4 constitutes the second intermediate M2. A laminate of the first intermediate M1 and the surface protective film 5 constitutes the third intermediate M3. Each component of the optical layered body 100 will be described below.

[Polarizing film 1]
The polarizing film 1 is composed of a polarizer 11 and protective films 12 and 13 that protect the polarizer 11 . In this embodiment, the protective films 12 and 13 are laminated on both sides of the polarizer 11, but the present invention is not limited to this, and the protective film may be laminated on at least one side of the polarizer 11. FIG.

(Polarizer 11)
The polarizer 11 is typically composed of a resin film containing a dichroic substance.
Any appropriate resin film that can be used as a polarizer can be adopted as the resin film. The resin film is typically a polyvinyl alcohol-based resin (hereinafter referred to as "PVA-based resin") film.

Any appropriate resin can be used as the PVA-based resin forming the PVA-based resin film. Examples thereof include polyvinyl alcohol and ethylene-vinyl alcohol copolymer. Polyvinyl alcohol is obtained by saponifying polyvinyl acetate. An ethylene-vinyl alcohol copolymer is obtained by saponifying an ethylene-vinyl acetate copolymer.

The average degree of polymerization of the PVA-based resin can be appropriately selected according to the purpose. The average degree of polymerization is usually 1,000 to 10,000, preferably 1,200 to 4,500, more preferably 1,500 to 4,300. The average degree of polymerization can be determined according to JIS K 6726-1994.

Dichroic substances contained in resin films include, for example, iodine and organic dyes. These can be used alone or in combination of two or more. Iodine is preferably used.

The resin film may be a single-layer resin film or a laminate of two or more layers.

A specific example of a polarizer composed of a single-layer resin film is a PVA-based resin film that is dyed with iodine and stretched (typically, uniaxially stretched). The dyeing treatment with iodine is performed, for example, by immersing the PVA-based film in an iodine aqueous solution. The draw ratio for uniaxial stretching is preferably 3 to 7 times. Stretching may be performed after dyeing, or may be performed while dyeing. Moreover, you may dye after extending|stretching. If necessary, the PVA-based resin film is subjected to swelling treatment, cross-linking treatment, washing treatment, drying treatment, and the like.

Specific examples of the polarizer composed of a laminate include a laminate of a resin base material and a PVA-based resin layer (PVA-based resin film) laminated on the resin base material, or a resin base material and the resin base material. A polarizer composed of a laminate with a PVA-based resin layer formed by coating on a material can be mentioned. A polarizer composed of a laminate of a resin base material and a PVA-based resin layer formed by coating on the resin base material can be obtained, for example, by applying a PVA-based resin solution to the resin base material and drying the resin base material. After forming a PVA-based resin layer on the substrate to obtain a laminate of the resin substrate and the PVA-based resin layer, the laminate is stretched and dyed to make the PVA-based resin layer into a polarizer. can be done. In this embodiment, stretching typically includes immersing the laminate in an aqueous boric acid solution and stretching. Furthermore, stretching may include stretching the laminate at a high temperature (eg, 95° C. or higher) in air before stretching in an aqueous boric acid solution, if necessary. The obtained resin substrate/polarizer laminate may be used as it is (that is, the resin substrate may be used as a protective layer for the polarizer), or the resin substrate may be removed from the resin substrate/polarizer laminate. It may be peeled off, and any appropriate protective layer may be laminated on the peeled surface according to the purpose. Details of a method for manufacturing such a polarizer are described, for example, in Japanese Patent Application Laid-Open No. 2012-73580. This publication is incorporated herein by reference in its entirety.

The thickness of the polarizer 11 is preferably 15 μm or less, more preferably 1 μm to 12 μm, even more preferably 3 μm to 10 μm, particularly preferably 3 μm to 8 μm.

The polarizer 11 preferably exhibits absorption dichroism at any wavelength within the wavelength range of 380 nm to 780 nm. The single transmittance of the polarizer 11 is preferably 40.0% to 45.0%, more preferably 41.5% to 43.5%. The degree of polarization of the polarizer 11 is preferably 97.0% or higher, more preferably 99.0% or higher, still more preferably 99.9% or higher.

(Protective films 12, 13)
Any appropriate resin film is used as the protective films 12 and 13 . Materials for forming the resin film include, for example, (meth)acrylic resins, cellulose resins such as diacetyl cellulose and triacetyl cellulose, cycloolefin resins such as norbornene resins, olefin resins such as polypropylene, and polyethylene terephthalate resins. ester-based resins, polyamide-based resins, polycarbonate-based resins, copolymer resins thereof, and the like. In addition, "(meth)acrylic resin" means an acrylic resin and/or a methacrylic resin. The materials for forming the protective films 12 and 13 may be the same or different.

The thickness of the protective films 12 and 13 is typically 10 μm to 100 μm, preferably 20 μm to 40 μm. The protective films 12 and 13 may have the same thickness or different thicknesses.

The surfaces of the protective films 12 and 13 opposite to the polarizer 11 may be subjected to surface treatment such as hard coat treatment, anti-reflection treatment, anti-sticking treatment, anti-glare treatment, etc., if necessary. Further/or, the surfaces of the protective films 12 and 13 opposite to the polarizer 11 are optionally treated to improve visibility when viewed through polarized sunglasses (typically, (elliptical) A treatment for imparting a circular polarization function, a treatment for imparting an ultra-high retardation) may be performed. In addition, when surface treatment is performed and a surface treatment layer is formed, the thickness of the protective films 12 and 13 is the thickness including the surface treatment layer.　

In addition, the protective films 12 and 13 are laminated by bonding to the polarizer 11 via any appropriate adhesive layer (not shown). The adhesive constituting the adhesive layer is typically a PVA-based adhesive or an activated energy ray-curable adhesive.

[Retardation film 2]
The retardation film 2 may be, for example, a compensator that provides a wide viewing angle, or a half-wave plate or quarter-wave plate that is used together with a polarizing film to generate circularly polarized light. A retardation plate (circularly polarizing plate) may be used. The thickness of the retardation film 2 is, for example, 1 to 200 μm.

The retardation film 2 is formed of, for example, a layer formed by polymerizing a polymerizable liquid crystal or a resin. A polymerizable liquid crystal is a compound having a polymerizable group and liquid crystallinity. A polymerizable group means a group that participates in a polymerization reaction, and is preferably a photopolymerizable group. Here, the photopolymerizable group means a group capable of participating in a polymerization reaction by an active radical generated from a photopolymerization initiator, an acid, or the like. Examples of the polymerizable group include vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, 4-vinylphenyl group, acryloyloxy group, methacryloyloxy group, oxiranyl group and oxetanyl group. Among them, an acryloyloxy group, a methacryloyloxy group, a vinyloxy group, an oxiranyl group and an oxetanyl group are preferred, and an acryloyloxy group is more preferred. The liquid crystallinity of the polymerizable liquid crystal may be either thermotropic liquid crystal or lyotropic liquid crystal, and thermotropic liquid crystal may be classified into nematic liquid crystal or smectic liquid crystal according to the degree of order.
Examples of resins forming the retardation film 2 include polyarylates, polyamides, polyimides, polyesters, polyaryletherketones, polyamideimides, polyesterimides, polyvinyl alcohols, polyfumarates, polyethersulfones, polysulfones, and norbornenes. Resins, polycarbonate resins, cellulosic resins and polyurethanes may be mentioned. These resins may be used alone or in combination.

Note that the retardation film 2 is attached and laminated to the polarizing film 1 (protective film 13) via any appropriate adhesive layer or adhesive layer (not shown). The adhesive constituting the adhesive layer is typically a PVA-based adhesive or an activated energy ray-curable adhesive.

[Adhesive layer 3]
The adhesive layer 3 is formed by applying an adhesive to one side of the separator 4 and curing the applied adhesive by heating and drying it in an oven or the like.
The heating temperature of the adhesive is preferably set in the range of 100°C to 160°C, more preferably set in the range of 140°C to 160°C. At this heating temperature, heating is preferably performed for 20 seconds to 3 minutes, more preferably 1 minute to 3 minutes.

Specific examples of adhesives forming the adhesive layer 3 include acrylic adhesives, rubber adhesives, silicone adhesives, polyester adhesives, urethane adhesives, epoxy adhesives, and polyether adhesives. Adhesives are mentioned. By adjusting the type, number, combination and compounding ratio of the monomers forming the base resin of the adhesive, the compounding amount of the cross-linking agent, the reaction temperature, the reaction time, etc., a pressure-sensitive adhesive having desired properties according to the purpose. can be prepared. The base resin of the adhesive may be used alone or in combination of two or more. Acrylic pressure-sensitive adhesives are preferred from the viewpoint of transparency, workability, durability, and the like. Details of the adhesive constituting the adhesive layer are described, for example, in JP-A-2014-115468, and the description of the publication is incorporated herein by reference. The thickness of the adhesive layer can be, for example, 10 μm to 100 μm.

[Separator 4]
Any appropriate separator can be adopted as the separator 4 . Specific examples include plastic films, non-woven fabrics or papers surface-coated with a release agent. Specific examples of release agents include silicone-based release agents, fluorine-based release agents, and long-chain alkyl acrylate-based release agents. Specific examples of plastic films include polyethylene terephthalate (PET) films, polyethylene films, and polypropylene films. The thickness of the separator 4 can be, for example, 10 μm to 100 μm.

[Surface protection film 5]
The surface protective film 5 typically has a substrate and an adhesive layer. In this embodiment, the thickness of the surface protective film 5 is, for example, 30 μm or more. The upper limit of the thickness of the surface protective film 5 is, for example, 150 μm. In addition, in this specification, "the thickness of a surface protection film" means the total thickness of a base material and an adhesive layer.

The base material can be composed of any suitable resin film. Materials for forming the resin film include ester resins such as polyethylene terephthalate resins, cycloolefin resins such as norbornene resins, olefin resins such as polypropylene, polyamide resins, polycarbonate resins, and copolymer resins thereof. is mentioned. Ester-based resins (especially polyethylene terephthalate-based resins) are preferred.

Any appropriate adhesive can be adopted as the adhesive that forms the adhesive layer. Examples of base resins for adhesives include acrylic resins, styrene resins, silicone resins, urethane resins, and rubber resins.

<Manufacturing method according to the present embodiment>
A method for manufacturing the optical layered body 100 according to the present embodiment for manufacturing the optical layered body 100 having the configuration described above will be described below.
FIG. 2 is a flowchart showing schematic steps of the method for manufacturing the optical layered body 100 according to this embodiment.
As shown in FIG. 2, the manufacturing method according to the present embodiment includes a polarizing film manufacturing step ST1, a retardation film bonding step ST2, a separator bonding step ST3, and an inspection step (the second separator peeling of the present invention). (also serving as a bonding step) ST4, a surface protective film bonding step ST5, and a first separator peeling/bonding step ST6. Each step ST1 to ST6 will be described below.

[Polarizing film manufacturing process ST1]
In the polarizing film manufacturing step ST1, a long belt-shaped resin film is used as a raw film, and this raw film is immersed in various treatment baths while being conveyed in the longitudinal direction (MD direction), and subjected to dyeing treatment, stretching treatment, etc. A long band-shaped polarizer 11 is manufactured by performing various treatments. Then, the long belt-shaped polarizing film 1 is manufactured by bonding the long belt-shaped protective films 12 and 13 to the long belt-shaped polarizer 11 .

[Retardation film bonding step ST2]
In the retardation film bonding step ST2, the long belt-like polarizing plate 10 is manufactured by bonding the long belt-like retardation film 2 to one side (protective film 13) of the long belt-like polarizing film 1.
When the optical layered body 100 does not include the retardation film 2 (the polarizing plate 10 does not include the retardation film 2), the retardation film bonding step ST2 is unnecessary.

[Separator bonding step ST3]
In the separator bonding step ST3, an adhesive is applied while conveying the long belt-shaped separator 4 in the longitudinal direction (MD direction), and the applied adhesive is dried by heating in an oven or the like to be cured and adhered. An adhesive layer forming step for forming the adhesive layer 3 is performed. Then, the separator 4 is attached to the long strip-shaped polarizing plate 10 via the adhesive layer 3 formed on the long strip-shaped separator 4 . Specifically, the adhesive layer 3 side of the long strip-shaped separator 4 (separator 4 with the adhesive layer 3 ) is attached to one side (retardation film 2 ) of the long strip-shaped polarizing plate 10 . Thereby, the second intermediate M2 in which the polarizing plate 10, the adhesive layer 3 and the separator 4 are laminated is manufactured.

[Inspection step (second separator peeling/bonding step) ST4]
Inspection process ST4 of this embodiment is performed before surface protective film bonding process ST5. In the inspection step ST4, the long belt-shaped separator 4 is peeled off from the adhesive layer 3 (while the adhesive layer 3 interposed between the separator 4 and the polarizing plate 10 remains on the polarizing plate 10 side, only the separator 4 is peeled off. ), the polarizing plate 10 is inspected. Then, after the polarizing plate 10 is inspected, the separated separator 4 is attached to the polarizing plate 10 again to restore the original state of the second intermediate M2.

FIG. 3 is a side view (viewed from the horizontal direction orthogonal to the conveying direction of each film) schematically showing an example of the schematic configuration of an apparatus that performs the inspection step ST4. The arrows shown in FIG. 3 mean the transport direction of each film.
In the inspection step ST4, the second intermediate M2 manufactured in the separator bonding step ST3 as described above is wound around the feeding roller R1 shown in FIG. (most upstream side in the conveying direction). Then, the second intermediate M2 delivered from the delivery roller R1 is conveyed toward the separation roller R2. The separation roller R2 separates the separator 4 from the second intermediate M2, and the separated separator 4 is conveyed toward the bonding roller R3.

On the other hand, the first intermediate M1, which is a laminate of the polarizing plate 10 and the adhesive layer 3, obtained by peeling the separator 4 from the second intermediate M2 by the peeling roller R2, is inspected by the inspection device 20. be done.
The inspection apparatus 20 shown in FIG. 3 is an apparatus that performs transmission inspection, and includes a light source 20a, an imaging means 20b, and a calculation means (not shown). The imaging means 20b of the inspection apparatus 20 receives the light emitted from the light source 20a and transmitted through the first intermediate M1 to form an image, and outputs an electric signal corresponding to the amount of light to the arithmetic means as an imaging signal. The computing means generates a transmission image based on the input imaging signal. Then, the computing means applies known image processing such as binarization for extracting a pixel region having a luminance value (pixel value) different from that of other pixel regions to the generated transparent image, thereby obtaining the first Defects present in the intermediate M1 (polarizing plate 10) are detected.
The inspection performed in the inspection step ST4 is not limited to the transmission inspection described above. A crossed Nicols image is generated by the light passing through the inspection polarizing filter and the first intermediate M1 arranged so as to be crossed Nicols with respect to the polarization axis of the polarizer 11 provided in the polarizing plate 10, and the crossed Nicols image is obtained. Based on this, it is also possible to employ a crossed Nicols inspection for detecting defects present in the first intermediate M1 (polarizing plate 10). Further, it is also possible to adopt reflection inspection for generating a reflection image by light reflected by the first intermediate M1 and detecting defects present in the first intermediate M1 (polarizing plate 10) based on this reflection image. be. Furthermore, it is also possible to perform any combination of transmission, crossed Nicols and reflex inspections.

After being inspected by the inspection device 20, the first intermediate M1 is conveyed toward the bonding roller R3. Then, the separator 4 is again bonded to the first intermediate M1 by the bonding roller R3. That is, the separator 4 is attached to the polarizing plate 10 forming the first intermediate M1 via the adhesive layer 3 forming the first intermediate M1. Thereby, the second intermediate M2 is manufactured and wound up by the winding roller R4. The separator 4 of the second intermediate M2 fed out from the feeding roller R1 and the separator 4 of the second intermediate M2 wound up by the winding roller R4 are the same separators 4 .

[Surface protective film bonding step ST5]
The surface protection film bonding step ST5 is performed before the first separator peeling/bonding step ST6. In the surface protection film bonding step ST5, the surface protection film 5 in a long belt shape is bonded to the second intermediate body M2 in a long belt shape. Specifically, a surface protective film 5 in the form of a long strip is attached to the surface of the polarizing plate 10 constituting the second intermediate M2 opposite to the side to which the separator 4 is attached. As a result, the long strip-shaped optical layered body 100 is manufactured.

[First separator peeling/bonding step ST6]
In the first separator peeling/bonding step ST6, the long strip-shaped separator 4 is peeled from the adhesive layer 3 of the long strip-shaped optical layered body 100 (interposed between the separator 4 and the polarizing plate 10). After peeling off only the separator 4 while leaving the adhesive layer 3 on the polarizing plate 10 side, the long strip-shaped separator 4 is attached to the polarizing plate 10 via the adhesive layer 3, thereby restoring the original optical laminate. Return to body 100.

FIG. 4 is a side view (viewed from the horizontal direction orthogonal to the conveying direction of each film) schematically showing an example of the schematic configuration of an apparatus that performs the first separator peeling/bonding step ST6. The arrows shown in FIG. 4 indicate the transport direction of each film.
In the first separator peeling/bonding step ST6, the optical layered body 100 manufactured in the surface protective film bonding step ST5 as described above is wound around a delivery roller R5 shown in FIG. side (the most upstream side in the conveying direction of the optical layered body 100). Then, the optical layered body 100 delivered from the delivery roller R5 is conveyed toward the separation roller R6. The separation roller R6 separates the separator 4 from the optical layered body 100, and the separated separator 4 is conveyed toward the bonding roller R7.

On the other hand, the third intermediate M3, which is a laminate of the surface protective film 5, the polarizing plate 10, and the adhesive layer 3 obtained by peeling the separator 4 from the optical laminate 100 by the peeling roller R6, was also applied. It is conveyed toward the joining roller R7. Then, the separator 4 is again bonded to the third intermediate M3 by the bonding roller R7. That is, the separator 4 is attached to the polarizing plate 10 forming the third intermediate M3 via the adhesive layer 3 forming the third intermediate M3. Thus, the optical laminate 100 is manufactured and wound up by the winding roller R8. The separator 4 of the optical layered body 100 delivered from the delivery roller R5 and the separator 4 of the optical layered body 100 taken up by the take-up roller R8 are the same separators 4 .
Since the manufacturing method according to the present embodiment includes the first separator peeling/bonding step ST6, peeling of the separator 4 and bonding of the separator 4 are performed. In other words, even if the separator 4 to be bonded is the same as the separator 4 to be peeled off, the separator 4 is bonded to the polarizing plate 10 in a state in which the unevenness of the separator 4 is extended. Since the first separator peeling/bonding step ST6 is performed after the surface protection film bonding step ST5, the separator 4 with the unevenness extended is attached to the highly rigid laminate (third intermediate M3). As a result, curling can be suppressed even if a force acts to return the separator 4 to the contracted state.
In addition, since the manufacturing method according to the present embodiment includes the inspection step ST4 as the second separator peeling/bonding step, the inspection step ST4 is performed not only after the surface protective film bonding step ST5 but also after the surface protective film bonding step ST5. , separation of the separator 4 and bonding of the separator 4 are also performed. Therefore, it is possible to further suppress curling.

In the present embodiment, in the first separator peeling/bonding step ST6, the time from peeling the long strip-shaped separator 4 to sticking the long strip-shaped separator 4 is within 1 minute, preferably within 45 seconds. , and more preferably within 30 seconds. Specifically, as shown in FIG. 4, when the length of the transport path of the optical layered body 100 from the peeling roller R6 to the bonding roller R7 is L, and the transport speed is V, L/V≤1 minute ( The length L of the conveying path and the conveying speed V are set so that the time is preferably 45 seconds, more preferably 30 seconds.
Thus, in the present embodiment, the time from peeling off the separator 4 to bonding the separator 4 together, in other words, the time during which the pressure-sensitive adhesive layer 3 is exposed is short. Or, even if the humidity in the first separator peeling/bonding step ST6 changes due to the influence of nighttime, the polarizing plate 10 absorbs moisture in the atmosphere from the adhesive layer 3 side and swells. It is possible to suppress variations in curls that occur.

The lamination of the third intermediate M3 and the separator 4 by the lamination roller R7 will be described in more detail below.
FIG. 5 is an explanatory diagram illustrating bonding of the third intermediate M3 and the separator 4 by the bonding roller R7. As shown in FIG. 5, the bonding roller R7 is comprised from a pair of 1st roller R71 and 2nd roller R72 which oppose. The 1st roller R71 is a roller which contacts the separator 4 and conveys the separator 4 between the 1st roller R71 and the 2nd roller R72. The surface of the first roller R71 is made of metal (for example, iron). The second roller R72 is a roller that contacts the third intermediate M3 and conveys the third intermediate M3 between the first roller R71 and the second roller R72. The surface of the second roller R72 is made of resin (for example, rubber).

As shown in FIG. 5, a straight line (virtual straight line) passing through the center of rotation C1 of the first roller R71 and the center of rotation C2 of the second roller R72 is defined as a straight line CL. Let a vector (virtual vector) orthogonal to the straight line CL and directed to the output side of the bonding roller R7 (right side in FIG. 5) be a vector VC. At this time, the entrance angle α of the separator 4 to the bonding roller R7 means the angle between the vector VC and the vector indicating the traveling direction of the separator 4 until it contacts the bonding roller R7. Further, the entrance angle of the third intermediate M3 to the bonding roller R7 (corresponding to the entrance angle of the polarizing plate 10 to the bonding roller R7) β is the vector VC and the third It means an angle formed with a vector indicating the traveling direction of the intermediate M3 (corresponding to the traveling direction of the polarizing plate 10).
In this embodiment, both the approach angle α and the approach angle β are set to less than 90°. Although α=90° and β=0° are shown in FIG. 4 for convenience, in reality, α<90° and β<90°, preferably 10°<α<80°. , more preferably 20°<α<50°. Also, preferably 0°<β<80°, more preferably 0°<β<75°. By increasing the approach angle α, the transportability of the third intermediate M3 (polarizing plate 10) is improved.

According to the findings of the present inventors, when the entrance angle α of the separator 4 to the bonding roller R7 is large (90° or more), the curl is in the TD direction and the curl is negative (the side on which the separator 4 is positioned is concave). When the angle β of the third intermediate M3 (polarizing plate 10) entering the bonding roller R7 is large (90° or more), the curl in the TD direction and the positive curl (separator The curl that becomes convex on the side where 4 is located increases.
Therefore, by setting α<90° and β<90° as described above, curling can be further suppressed.

In this embodiment, in the first separator peeling/bonding step ST6, the case where the separated separator 4 and the separator 4 to be bonded are the same separator 4 has been described as an example, but the present invention is not limited to this. It is not limited. In the first separator peeling/bonding step ST6, the separated separator 4 and the bonded separator 4 may be different separators 4 . A modification of the first separator peeling/bonding step ST6 in which the peeled separator 4 and the separator 4 to be bonded are different will be described below.

In the modified example of the first separator peeling/bonding step ST6, a new separator 4 different from the peeled separator 4 is bonded to the polarizing plate 10 with the adhesive layer 3 interposed therebetween. Hereinafter, the separator 4 to be peeled (separator 4 bonded in the inspection step ST4) will be referred to as “separator 4a”, and the new separator 4 bonded in the modified example of the first separator peeling and bonding step ST6 will be referred to as “separator 4b. ” to distinguish between the two.

FIG. 6 is a side view (viewed from the horizontal direction orthogonal to the conveying direction of each film) schematically showing an example of the schematic configuration of an apparatus that performs a modification of the first separator peeling/bonding step ST6. . The arrows shown in FIG. 6 indicate the transport direction of each film.
In the modified example of the first separator peeling/bonding step ST6, the optical layered body 100 manufactured in the surface protection film bonding step ST5 as described above is wound around a delivery roller R9 shown in FIG. (the most upstream side in the conveying direction of the optical layered body 100). Then, the optical layered body 100 delivered from the delivery roller R9 is conveyed toward the separation roller R10. The separation roller R10 separates the separator 4a from the optical layered body 100, and the separated separator 4a is taken up by the take-up roller R11.

On the other hand, the third intermediate M3, which is a laminate of the surface protective film 5, the polarizing plate 10, and the adhesive layer 3, obtained by peeling the separator 4a from the optical layered body 100 by the peeling roller R10, It is conveyed toward the joining roller R12. In addition, a new separator 4b wound around the delivery roller R13 (that is, a separator that is less likely to be uneven because it is not heated for forming the adhesive layer 3) is prepared. , and conveyed toward the bonding roller R12. Then, the separator 4b is bonded to the third intermediate M3 by the bonding roller R12. That is, the separator 4b is attached to the polarizing plate 10 forming the third intermediate M3 via the adhesive layer 3 forming the third intermediate M3. Thus, the optical layered body 100 is manufactured and wound up by the winding roller R14. The separator 4 of the optical layered body 100 delivered from the delivery roller R9 is the separator 4a, but the separator 4 of the optical layered body 100 wound up by the take-up roller R14 is the separator 4b.
According to the modification of the first separator peeling/bonding step ST6, curling can be further suppressed because a new separator 4b different from the peeled separator 4a is bonded.
In this modified example, the elastic modulus (elastic modulus in the TD direction) of the new separator 4b bonded to the polarizing plate 10 in the modified example of the first separator peeling/bonding step ST6 is, for example, 6000 [N/mm ² ]. ] On the other hand, the elastic modulus (elastic modulus in the TD direction) of the separator 4a after the pressure-sensitive adhesive layer forming step (that is, after heating) in the separator bonding step ST3 is, for example, less than 6000 [N/mm ² ]. , the elastic modulus of the separator 4b is higher than that of the separator 4a. If the elastic modulus of the separator 4b is higher than the elastic modulus of the separator 4a, the new separator 4b that is bonded (re-bonded) in the modified example of the first separator peeling/bonding step ST6 is difficult to shrink. Curling can be suppressed even more. Although the upper limit of the elastic modulus (the elastic modulus in the TD direction) of the separator 4b is not particularly limited, it is, for example, 7000 [N/mm ² ] or less, preferably 6500 [N/mm ² ] or less. Although the lower limit of the elastic modulus (the elastic modulus in the TD direction) of the separator 4a is not particularly limited, it is, for example, 5000 [N/mm ² ] or more, preferably 5500 [N/mm ² ] or more.
The elastic modulus can be measured using, for example, a tensile tester "Autograph" manufactured by Shimadzu Corporation. Specifically, from the separators 4a and 4b alone, a sample with a width (dimension in the MD direction) of 10 mm and a length (dimension in the TD direction) of 100 mm is cut out, and this sample is set in an autograph, and is measured in the TD direction. The elastic modulus can be calculated based on the force [N] applied to stretch the sample by a predetermined amount by pulling it at a speed of 50 mm/min.

In the modified example of the first separator peeling/bonding step ST6, the separator 4a is peeled off by the peeling roller R10 in the same manner as the first separator peeling/bonding step ST6 described with reference to FIGS. 1 minute or less, preferably 45 seconds or less, and more preferably 30 seconds or less until the separator 4b is bonded by the bonding roller R12. Also in the modified example of the first separator peeling/bonding step ST6, of the pair of facing rollers constituting the bonding roller R12, the roller that contacts the separator 4b and conveys the separator 4b between the pair of rollers The surface of is made of metal (eg, iron). The surfaces of the rollers that come into contact with the third intermediate M3 and convey the third intermediate M3 between the pair of rollers are made of resin (eg, rubber). Furthermore, in the modified example of the first separator peeling/bonding step ST6, the approach angle α of the separator 4b to the bonding roller R12 and the approach angle β of the third intermediate M3 (polarizing plate 10) to the bonding roller R12 are set to less than 90°. As a result, curling can be further suppressed even in the modified example of the first separator peeling/bonding step ST6. The entrance angle α of the separator 4b to the bonding roller R12 and the entrance angle β of the third intermediate M3 (polarizing plate 10) to the bonding roller R12 are preferably 10°<α<80°, more preferably is 20°<α<50°. Also, preferably 0°<β<80°, more preferably 0°<β<75°. By increasing the approach angle α, the transportability of the third intermediate M3 (polarizing plate 10) is improved.

Also in the inspection step ST4 described with reference to FIG. 3, the separator 4 is peeled off by the peel roller R2 in the same manner as in the first separator peeling/bonding step ST6 described with reference to FIGS. 1 minute or less, preferably 45 seconds or less, and more preferably 30 seconds or less until the separator 4 is bonded by the bonding roller R3. Also in the inspection step ST4, similarly to the first separator peeling/bonding step ST6, the separator 4 is brought into contact with the separator 4 of the pair of opposing rollers constituting the bonding roller R3, and the separator 4 is separated between the pair of rollers. The surface of the roller that conveys is made of metal (for example, iron). The surfaces of the rollers that come into contact with the first intermediate M1 and convey the first intermediate M1 between the pair of rollers are made of resin (for example, rubber). Also, in the inspection step ST4, as in the first separator peeling/bonding step ST6, the approach angle α of the separator 4 to the bonding roller R3 and the first intermediate M1 (polarizing plate 10) to the bonding roller R3 are set to less than 90°. As a result, curling can be further suppressed even in the inspection step ST4. Furthermore, in the inspection step ST4, a new separator 4 different from the peeled separator 4 is attached to the polarizing plate 10 after the inspection in the same manner as in the modification of the first separator peeling/bonding step ST6 described with reference to FIG. It is also possible to employ a mode of matching. The entrance angle α of the separator 4 to the bonding roller R3 and the entrance angle β of the first intermediate M1 (polarizing plate 10) to the bonding roller R3 are preferably 10°<α<80°, more preferably is 20°<α<50°. Also, preferably 0°<β<80°, more preferably 0°<β<75°. By increasing the approach angle α, the transportability of the first intermediate M1 (polarizing plate 10) is improved.

According to the manufacturing method according to the present embodiment described above, curling can be effectively suppressed without particularly changing the materials of the constituent elements of the conventionally used optical layered body 100 .

In the present embodiment, the inspection step ST4 also serves as the second separator peeling/bonding step, but the present invention is not limited to this, and the inspection step ST4 and the second separator peeling/bonding step have been described. It is also possible to perform the steps separately. Alternatively, it is also possible to employ a mode in which no inspection is performed in the inspection step ST4 (that is, a second separator peeling/bonding step of simply peeling and bonding the separator 4 is performed). Alternatively, it is possible to employ a mode in which the inspection step ST4 itself is not performed (that is, the separation and bonding of the separator 4 are performed only in the first separator peeling/bonding step ST6).

In addition, in the present embodiment, an aspect in which the polarizing plate 10 is a laminate of the polarizing film 1 and the retardation film 2 has been described as an example, but the present invention is not limited to this. An aspect in which the polarizing plate 10 is a laminate of the polarizing film 1, the retardation film 2, and other components, or a configuration in which the polarizing plate 10 is a laminate of the polarizing film 1 and other components without the retardation film 2 present It is also possible to employ a mode in which the polarizing plate 10 is a laminate, or a mode in which only the polarizing film 1 is present in the polarizing plate 10 .

Hereinafter, an example of the results of evaluating the curl of the optical laminate 100 manufactured by the manufacturing method (example) according to the present embodiment shown in FIG. An example of the results of evaluating the curl of the laminate will be described.
Each of the optical laminates 100 manufactured in Examples and Comparative Examples has a structure in which layers are laminated in the following order.
(1) Surface protection film 5 (base material: PET/thickness 38 μm, adhesive layer: acrylic adhesive/thickness 10 μm)
(2) Cycloolefin-based protective film 12 (total thickness: 32 μm) with hard coat layer (thickness: 7 μm)
(3) Adhesive (4) Polyvinyl alcohol polarizer 11 (thickness 12 μm)
(5) Adhesive (6) Triacetyl cellulose protective film 13 (thickness 25 μm)
(7) Adhesive (8) Polymerizable liquid crystal half-wave plate 2 (thickness: 2.5 μm)
(9) Acrylic adhesive layer 3 (thickness 20 μm)
(10) Separator 4 (PET, thickness 38 μm)
In the optical layered body 100 produced in the example, in the first separator peeling/bonding step ST6 and the inspection step ST4, the same separator 4 as the peeled separator 4 was bonded to the polarizing plate 10 after the inspection (second In the separator peeling/bonding step ST6 and the inspection step ST4 of No. 1, the separator 4 was not replaced.

FIG. 7 is an explanatory diagram for explaining a curl evaluation method.
As shown in FIG. 7A, in the example, a plurality of rectangular optical layered bodies 100S having a product size (148 mm long×70 mm wide) were cut out along the TD direction of the long optical layered body 100. . Although three optical layered bodies 100S are shown in FIG. 7A for convenience, ten optical layered bodies 100S were actually cut from one optical layered body 100 along the TD direction. This was carried out for a plurality of optical layered bodies 100 to obtain a total of 500 optical layered bodies 100S. Then, 100 optical laminates 100S randomly selected from the 500 optical laminates 100S were evaluated for curl. As shown in FIG. 7B, when cutting out the optical layered body 100S, the MD direction of the optical layered body 100 (corresponding to the direction of the absorption axis of the polarizer 11) is the long side of the optical layered body 100S. and cut obliquely at 45° to the short side.

As shown in FIG. 7C, when evaluating the curl, the lower side of the optical layered body 100S is convex (the four corners of the optical layered body 100S are warped upward in the vertical direction). ), the optical layered body 100S was placed on a flat mounting table 30, and the vertical distance H from the upper surface of the mounting table 30 to each of the four corners of the optical layered body 100S was measured. The distance H was measured by setting a vertically extending scale in the vicinity of the corner of the optical layered body 100S and visually reading the scale on the scale.
When the optical layered body 100S is placed on the mounting table 30 so that the lower side of the optical layered body 100S is convex, the side of the optical layered body 100S on which the separator 4 is positioned faces downward (the side on which the surface protective film 5 is positioned faces upward). was taken as a positive curl, and the measured distance H was directly calculated as the curl value. On the other hand, when the optical layered body 100S is placed on the mounting table 30 so that the lower side of the optical layered body 100S is convex, the side of the optical layered body 100S on which the separator 4 is positioned faces upward (the side on which the surface protective film 5 is positioned faces downward). ) was regarded as a negative curl, and the value obtained by multiplying the measured distance H by -1 was calculated as the curl value.

Next, the separator 4 was peeled off from the optical layered body 100S to form a third intermediate M3. Then, the curl values of the four corners of the third intermediate M3 were calculated in the same procedure as described above.

A case where the curl values of the four corners of the optical layered body 100S and the curl values of the four corners of the third intermediate M3 satisfy the condition of -5 mm ≤ curl value ≤ 5 mm is regarded as passed and satisfied. If not, it was regarded as unsatisfactory.
Also for the comparative example, the curl value was calculated in the same procedure as the example described above, and it was determined whether it passed or failed.

Table 1 shows the curl evaluation results of Examples and Comparative Examples.

As shown in Table 1, in the comparative example, 44 out of 100 optical laminates passed (acceptance rate of 44%), whereas in the example, 95 out of 100 optical laminates was found to be acceptable (acceptance rate of 95%), and curling was suppressed.

DESCRIPTION OF SYMBOLS 1... Polarizing film 10... Polarizing plate 11... Polarizer 12, 13... Protective film 2... Retardation film 3... Adhesive layer 4... Separator 5... Surface Protective film 100, 100S Optical laminate ST1 Polarizing film manufacturing process ST2 Retardation film bonding process ST3 Separator bonding process ST4 Inspection process (second separator peeling/ bonding process)
ST5: Surface protection film bonding step ST6: First separator peeling/bonding step

Claims (8)

1. A separator bonding step of bonding the separator to a long strip-shaped polarizing plate via an adhesive layer formed on the long strip-shaped separator;
   After the separator bonding step, a surface protective film bonding step of bonding a long strip-shaped surface protective film to the polarizing plate;
   After the surface protective film lamination step, after peeling a long strip-shaped separator from the adhesive layer, a long strip-shaped separator is stuck to the polarizing plate via the adhesive layer. including a lamination step;
   A method for manufacturing an optical laminate.
2. The separator lamination step includes an adhesive layer forming step of applying an adhesive to a long belt-shaped separator and heating and curing the applied adhesive to form the adhesive layer.
   The method for manufacturing the optical layered body according to claim 1 .
3. Before the surface protective film lamination step, after peeling the long strip-shaped separator from the adhesive layer, the long strip-shaped separator is stuck to the polarizing plate via the adhesive layer. Second separator peeling.・Including lamination process
   3. The method for producing the optical layered body according to claim 1 or 2.
4. The second separator peeling/bonding step also serves as an inspection step of inspecting the polarizing plate after peeling the long strip-shaped separator.
   The method for manufacturing the optical laminate according to claim 3.
5. In the first separator peeling and bonding step, the time from peeling the long strip separator to bonding the long strip separator is within 1 minute.
   5. A method for manufacturing an optical layered body according to claim 1.
6. In the first separator peeling and bonding step, a long belt-shaped separator and the polarizing plate are bonded together by a bonding roller,
   The entrance angle of the separator to the bonding roller is less than 90°, and the entrance angle of the polarizing plate to the bonding roller is less than 90°.
   The method for producing an optical layered body according to any one of claims 1 to 5.
7. The bonding roller is composed of a first roller that contacts the separator and a second roller that contacts the polarizing plate,
   One surface of the first roller and the second roller is made of resin and the other surface is made of metal,
   The method for producing an optical laminate according to claim 6.
8. The first roller has a surface formed of metal,
   The second roller has a surface formed of resin,
   The method for manufacturing the optical laminate according to claim 7.

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