TW202304714A - Method for manufacturing optical laminate - Google Patents

Abstract

To provide a method for manufacturing an optical laminate capable of suppressing curl. A method for manufacturing an optical laminate 100 includes: a separator sticking step ST3 of sticking a separator 4 to a polarizing plate 10 via an adhesive layer 3 formed in the separator; and a plurality of separator peeling and sticking steps ST4 of sticking the separator to the polarizing plate via the adhesive layer after peeling the separator from the adhesive layer. Of the plurality of separator peeling and sticking steps, at least one separator peeling and sticking step is a separator replacing step ST41 of sticking a new separator different from the peeled separator to the polarizing plate via the adhesive layer.

Description

Manufacturing method of optical laminated body

The present invention relates to a manufacturing method of an optical layered body, the optical layered system comprising at least a polarizing plate and a separator. Especially, this invention relates to the manufacturing method of the optical laminated body which can suppress a curl.

Conventionally, polarizing plates have been used as constituent materials of liquid crystal display devices, organic EL display devices, and the like. In addition to the polarizing film, the polarizing plate also has a retardation film according to the application. The 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. The strip-shaped polarizing film is manufactured by attaching the strip-shaped protective film to at least one side of the strip-shaped polarizer. A long strip-shaped retardation film and the like are pasted on one side of the produced long strip-shaped polarizing film to manufacture a long strip-shaped polarizing plate. Attach a long strip-shaped separator (release film) to one side of the long strip-shaped polarizing plate produced, and attach a long strip-shaped surface protection film to the other side to produce a long strip-shaped optical laminated body. The lamination of the strip-shaped films is usually carried out in a roll-to-roll or roll-to-sheet manner. The produced long strip-shaped optical laminate system is cut into a size or shape suitable for the application and used for liquid crystal display devices and the like. In addition, 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. 7 is a flow chart showing an example of schematic steps of a conventional method for producing an optical laminate. As shown in Figure 7, the conventional manufacturing method of optical laminates includes: polarizing film manufacturing step ST1', retardation film bonding step ST2', separator bonding step ST3', inspection step ST4' and surface protection film bonding Step ST5'. In the polarizing film manufacturing step ST1', a long strip-shaped resin film is used as the original film, and the original film is immersed in various treatment baths while being conveyed in the longitudinal direction, and various treatments such as dyeing treatment and stretching treatment are performed. , to manufacture long strip polarizers. Then, a long strip-shaped polarizing film is produced by attaching a long strip-shaped protective film to at least one side of the long strip-shaped polarizer. In the retardation film lamination step ST2', a long strip-shaped retardation film (1/2 wavelength plate or 1/4 wavelength plate, etc.) is pasted on one side of the long strip-shaped polarizing film, thereby manufacturing a long Striped polarizer.

In the separator bonding step ST3', the adhesive is applied while conveying the long strip-shaped separator in the longitudinal direction, and the applied adhesive is heated in an oven to dry and harden. , forming an adhesive layer. Then, by bonding the adhesive layer side of the long strip-shaped separator (adhesive layer-attached separator) to one side of the long strip-shaped polarizing plate, a laminated polarizing plate, adhesive layer, and The long strip-shaped intermediate body of the separator. In the inspection step ST4', the polarizer is inspected after peeling off only the separator with the adhesive layer interposed between the separator and the polarizer left on the polarizer side. Inspection methods for polarizers include transmission inspection, cross-polarization inspection, reflection inspection, etc. In the inspection step ST4', after inspecting the polarizer, the separated separator is attached to the polarizer again, thereby returning to the original intermediate state.

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

However, in the optical layered body produced in the above manner, the optical layered body after cutting into the product size may produce curl (end warpage) which becomes a problem in use. For example, Patent Document 1 proposes to use a specific material as the material of the protective film protecting the polarizer as a method of suppressing the curling of the polarizing film, but the material of the protective film is limited, so it is not universally used. Therefore, there is a demand for a method of suppressing curl without particularly changing the materials of the constituent elements of the conventionally used optical layered body. prior art literature patent documents

Patent Document 1: Japanese Patent Laid-Open No. 2007-256568

The problem to be solved by the invention The present invention is made in order to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a method of manufacturing an optical laminate that can suppress curl.

means to solve problems In order to solve the aforementioned problems, the inventors of the present invention actively studied and found that in the step of laminating the separator (ST3' in FIG. One of the main causes of curling in laminates. Specifically, we thought that when the adhesive coated on the separator was heated and dried, the separator would shrink and unevenness would be generated in the thickness direction thereof. And when the separator is attached to the polarizer in the step of attaching the separator, or when the separator is attached to the polarizer again in the inspection step (ST4' of FIG. 7 ), although it is caused by heating The concavities and convexities on the separator are bonded in a stretched state, but after a lapse of time after bonding, the force to return to the contracted state of the separator acts, and this causes curling of the optical laminate. The inventors of the present invention focused on the above-mentioned causes of occurrence and conducted further research. As a result, they found that the following method can effectively suppress the occurrence of curling. This method is as follows: as in the conventional inspection step, the separator is attached after the separator is peeled off, and the separator is peeled off. The step of attaching the separator is performed multiple times; and, in the plurality of steps, in at least one step, a new separator different from the peeled separator (not implemented for forming Adhesive layer heated separation parts). The present invention was accomplished in view of the above findings of the present inventors.

That is, in order to solve the above-mentioned problems, the present invention provides a method of manufacturing an optical laminate, including the following steps: a step of attaching a separator, which is to attach the separator to a polarizer through an adhesive layer formed on the separator. plate; and multiple times of peeling and bonding steps of the separator, which are after peeling the separator from the aforementioned adhesive layer, and bonding the separator to the aforementioned polarizing plate through the aforementioned adhesive layer; multiple times of the aforementioned separation In the part peeling and bonding step, at least one of the above separation part peeling and bonding steps is a separation part replacement step. The separator is pasted on the aforementioned polarizer.

In the step of peeling and bonding the separator of the present invention, the separated separator and the separator to be bonded are not limited to different separators, and may be the same separator. That is, the step of peeling and attaching the separator of the present invention also includes a case where the separator is peeled from the adhesive layer (only the separator is peeled off while the adhesive layer is left in the state of the polarizing plate), and the The same separator is attached to the polarizer again. However, at least one step of peeling and attaching the separator is a replacement step, and this replacement step is to attach a new separator different from the peeled separator to the polarizing plate through the adhesive layer. According to the present invention, the peeling of the separator and the bonding of the separator are repeated by including a plurality of steps of peeling and bonding of the separator. In other words, even if the separator to be attached is the same as the separator to be peeled off, curling can be suppressed by repeating the operation of attaching the separator to the polarizing plate a plurality of times while the unevenness of the separator is stretched. In addition, because at least one step of peeling and attaching the separator is a step of replacing the separator, the step of replacing the separator is to attach a new separator different from the peeled separator (that is, it is not implemented The heating used to form the adhesive layer makes it difficult to produce uneven separators), so curling can be more suppressed.

In the present invention, among the plurality of steps of peeling and bonding the separator, at least one step of peeling and bonding the separator is performed, for example, after the step of replacing the separator.

In the present invention, it is preferable that among the plurality of steps of peeling and attaching the aforementioned separator, at least one step of peeling and attaching the aforementioned separator is also used as an inspection step. The inspection step is to inspect the aforementioned polarizing plate after peeling off the separator. . According to the above ideal method, at least one step of peeling and attaching the separator is also used as the inspection step of the polarizing plate, so compared with the case where the step of peeling and attaching the separator and the inspection step are separately provided, the manufacturing process is simplified. advantage.

It is preferable that the present invention includes a step of attaching a surface protection film, and the step of attaching a surface protection film is to attach a surface protection film to the aforementioned polarizer after the step of replacing the aforementioned separator.

The step of attaching the separator includes, for example, an adhesive layer forming step. The adhesive layer forming step is to apply an adhesive to the separator, and heat the applied adhesive to harden to form the adhesive layer. Moreover, in the step of replacing the separator, the modulus of elasticity of the new separator to be bonded to the polarizer is higher than that of the separator after the step of forming the adhesive layer. As in the above ideal method, if the elastic modulus of the new separator to be attached to the polarizing plate is higher than the elastic modulus of the separator after the step of forming the adhesive layer included in the step of replacing the separator (that is, after heating) Therefore, the new separating member to be bonded (to be replaced) in the step of replacing the separating member is less likely to be deformed, so curling can be more suppressed.

In the step of peeling and attaching the separator, the time from peeling the separator to attaching the separator is preferably within 1 minute. According to the above-mentioned ideal method, the time from peeling off the separator to bonding the separator is short, in other words, the time for the adhesive layer to be exposed is short. Therefore, for example, even if the humidity in the separator peeling and bonding step changes due to seasonal effects or daytime or nighttime effects, swelling caused by the polarizing plate absorbing moisture in the air environment from the adhesive layer side can be suppressed. The curl that occurs varies.

Preferably, in the step of peeling and bonding the separator, the separating member and the polarizing plate are bonded by a bonding roller; the angle of entry of the separating member into the bonding roller is less than 90°, and the polarizing plate enters the laminating The entry angle of the drum is less than 90°.

In the above ideal method, "the entry angle of the separator into the laminating drum" means: a vector perpendicular to a straight line passing through the rotation center of a pair of opposing drums constituting the laminating drum and facing the sending side of the laminating drum, and Indicates the angle formed by the vector of the traveling direction of the separator until it contacts the laminating roller. Similarly, "the entry angle of the polarizing plate into the laminating drum" means: a vector perpendicular to a straight line passing through the rotation center of a pair of drums constituting the laminating drum and directed toward the delivery side of the laminating drum, and indicating the direction from which the polarizing plate to The angle formed by the vector in the direction of travel until it touches the bonding roller. According to the findings of the inventors of the present invention, if the entry angle of the separator into the bonding drum is large (more than 90°), the TD direction (direction perpendicular to the conveying direction (MD direction) of the long strip-shaped optical laminate) and The negative curl (concave curl on the side where the separator exists) will become larger, and if the angle of entry of the polarizer into the lamination drum is large (more than 90°), the TD direction will be positive curl (the separator exists Curl with a convex side) will become larger. According to the ideal method described above, curling can be further suppressed by making both the entry angles of the separator and the polarizing plate into the bonding drum smaller than 90°.

Preferably, the bonding roller is composed of a first roller contacting the separator and a second roller contacting the polarizing plate, and the surface of one of the first roller and the second roller is made of resin, and the other The surface of one is formed 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, there is a problem at the interface between the separator and the polarizing plate (the interface between the separator and the adhesive layer). Risk of bubbles. When both the surface of the 1st roller and the surface of the 2nd roller are formed of resin, there exists a possibility that wrinkles may generate|occur|produce in a separator. According to the above preferred method, since one of the surfaces of the first roller and the second roller is formed of resin and the surface of the other is formed of metal, the occurrence of air bubbles or wrinkles can be suppressed.

Preferably, the surface of the first roller is made of metal, and the surface of the second roller is made of resin. According to the above ideal method, in addition to suppressing the occurrence of bubbles or wrinkles, since the surface of the second roller that contacts the polarizing plate is formed of resin (because it is not formed of metal), it can also suppress the occurrence of scratches or dents on the polarizing plate. The appearance is bad.

Invention effect According to the present invention, curling can be effectively suppressed without particularly changing the materials of the constituent elements of the conventionally used optical layered body.

Hereinafter, a method of manufacturing an optical layered body according to an embodiment of the present invention will be described with reference to the attached drawings. In addition, since the figures are for reference only, it should be noted that the dimensions, scales, and shapes of the components of the optical layered body or device shown in the figures may differ from the actual ones.

＜Composition of optical laminate＞ First, the structure of the optical layered body manufactured by the manufacturing method of this embodiment is demonstrated. FIG. 1 is a cross-sectional view schematically showing a schematic configuration of an optical layered body manufactured by the manufacturing method of this embodiment. As shown in FIG. 1 , an 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 protection film 5 . The lamination system of the polarizing film 1 and the retardation film 2 constitutes a polarizing plate 10 . The lamination system of the polarizer 10 and the adhesive layer 3 constitutes the first intermediate M1. The layered system of the first intermediate body M1 and the separator 4 constitutes the second intermediate body M2. Hereinafter, each component of the optical layered body 100 will be described.

[Polarizing film 1] The polarizing film 1 is composed of a polarizer 11 and protective films 12 and 13 for protecting the polarizer 11 . In this embodiment, the protective films 12 and 13 are pasted on both sides of the polarizer 11 , but the present invention is not limited thereto, as long as a protective film is pasted on at least one side of the polarizer 11 .

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

Any appropriate resin can be used for the PVA-based resin forming the above-mentioned PVA-based resin film. Examples thereof include polyvinyl alcohol and ethylene-vinyl alcohol copolymers. Polyvinyl alcohol can be obtained by saponifying polyvinyl acetate. Ethylene-vinyl alcohol copolymer can be obtained by saponifying 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 1000-10000, preferably 1200-4500, more preferably 1500-4300. In addition, the average degree of polymerization can be obtained in accordance with JIS K 6726-1994.

Examples of the dichroic substance contained in the resin film include iodine and organic dyes. These can be used individually or in combination of 2 or more types. Preferably iodine can be 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 one in which a PVA-based resin film has been subjected to dyeing treatment with iodine and stretching treatment (typically, uniaxial stretching treatment). The dyeing treatment with iodine is performed, for example, by immersing a PVA-based film in an iodine aqueous solution. The elongation ratio of uniaxial stretching should be 3~7 times. Elongation can be performed after dyeing or while dyeing. In addition, dyeing may be performed after elongation. Swelling treatment, cross-linking treatment, cleaning treatment, drying treatment, etc. are performed on the PVA resin film according to the needs.

Specific examples of a polarizer made of a laminate include a laminate using a resin base material and a PVA-based resin layer (PVA-based resin film) laminated on the resin base material, or a laminate formed of a resin base material and a coating layer. A polarizer made of a laminate of PVA-based resin layers of the resin substrate. A polarizer composed of a laminate of a resin substrate and a PVA-based resin layer coated and formed on the resin substrate can be produced, for example, by applying a PVA-based resin solution to the resin substrate and drying it. , forming a PVA-based resin layer on a resin substrate, obtaining a laminate of the resin substrate and the PVA-based resin layer, stretching and dyeing the laminate to make the PVA-based resin layer into a polarizer. In the present embodiment, extending typically includes immersing and extending the laminate in an aqueous solution of boric acid. If necessary, the stretching may include stretching the laminate in air at a high temperature (for example, 95° C. or higher) before stretching in a boric acid aqueous solution. The laminate of the obtained resin substrate/polarizer can be used directly (i.e., the resin substrate can be used as a protective layer of the polarizer), or the resin substrate can be peeled off from the laminate of the resin substrate/polarizer and placed on the peeled area Any suitable protective layer suitable for the purpose is subsequently used. The details of the manufacturing method of the polarizer are described in, for example, Japanese Patent Laid-Open No. 2012-73580. In this specification, the entire description of the publication is incorporated by reference.

The thickness of the polarizer 11 is preferably less than 15 µm, more preferably 1 µm-12 µm, more preferably 3 µm-10 µm, especially 3 µm-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%-45.0%, more preferably 41.5%-43.5%. The degree of polarization of the polarizer 11 is preferably 97.0% or higher, more preferably 99.0% or higher, more preferably 99.9% or higher.

(protective film 12, 13) Any appropriate resin film can be used for the protective films 12 and 13 . Examples of materials for forming the resin film include (meth)acrylic resins, cellulose resins such as cellulose diacetate and cellulose triacetate, cycloolefin resins such as norbornene resins, olefin resins such as polypropylene, and polypropylene resins. Ester-based resins such as ethylene terephthalate-based resins, polyamide-based resins, polycarbonate-based resins, and their copolymer resins, etc. 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 as or different from each other.

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

Surfaces of the protective films 12 and 13 opposite to the polarizer 11 may also be treated with surface treatments such as hard coating, anti-reflection, anti-adhesion, and anti-glare as required. And/or, the surface of the protective film 12, 13 on the opposite side to the polarizer 11 can also be treated to improve the visibility when viewing through polarized sunglasses (representatively, to give (elliptical) polarizing function) processing, processing of imparting ultra-high phase difference). In addition, when performing surface treatment to form a surface treatment layer, the thickness of the protective films 12 and 13 includes the thickness of the surface treatment layer.

In addition, the protective films 12 and 13 are laminated by being respectively attached to the polarizer 11 through any appropriate adhesive layer (not shown). Representative adhesives constituting the adhesive layer include PVA-based adhesives or activated energy ray-curable adhesives.

[Retardation film 2] The retardation film 2 can be, for example, a compensation plate that provides a wide viewing angle, or a retardation plate (circular polarizing plate) such as a 1/2 wavelength plate or a 1/4 wavelength plate that is used together with a polarizing film to generate circularly polarized light. . The thickness of the retardation film 2 is, for example, 1-200 μm.

The retardation film 2 can be formed using, for example, a layer formed by polymerizing a polymerizable liquid crystal or a resin. A polymerizable liquid crystal refers to a compound having a polymerizable group and having liquid crystallinity. The polymerizable group means a group that participates in a polymerization reaction, and is preferably a photopolymerizable group. Here, the photopolymerizable group means a group that can participate in a polymerization reaction by an active radical generated from a photopolymerization initiator, an acid, or the like. Examples of polymerizable groups include vinyl, vinyloxy, 1-chlorovinyl, isopropenyl, 4-vinylphenyl, acryloxy, methacryloxy, oxiranyl, oxygen Heterobutanyl, etc. Among them, acryloxy, methacryloxy, vinyloxy, oxiranyl and oxetanyl are preferred, and acryloxy is more preferred. The liquid crystal property of polymerizable liquid crystals can be either thermotropic liquid crystals or lyotropic liquid crystals. If thermotropic liquid crystals are classified by degree of order, they can be nematic liquid crystals or smectic liquid crystals. Further, the resin forming the retardation film 2 includes, for example, polyarylate, polyamide, polyimide, polyester, polyaryletherketone, polyamideimide, polyesterimide, polyethylene Alcohol, polyfumarate, polyethersulfone, polysulfone, norbornene resin, polycarbonate resin, cellulose resin and polyurethane. These resins may be used alone or in combination.

In addition, the retardation film 2 is laminated by laminating the polarizing film 1 (protective film 13 ) through any appropriate adhesive layer or adhesive layer (not shown). Representative adhesives constituting the adhesive layer include PVA-based adhesives or activated energy ray-curable adhesives.

[Adhesive layer 3] The adhesive layer 3 is formed by applying an adhesive to one side of the separator 4 and heating the applied adhesive with an oven to dry and harden it. The heating temperature of the adhesive should be set in the range of 100°C~160°C, more preferably in the range of 140°C~160°C. It is advisable to heat at this heating temperature for 20 seconds to 3 minutes, more preferably for 1 minute to 3 minutes.

Specific examples of the adhesive forming the adhesive layer 3 include acrylic adhesives, rubber adhesives, silicone adhesives, polyester adhesives, urethane adhesives, epoxy adhesives, and Polyether adhesive. By adjusting the monomer type, quantity, combination and blending ratio of the base resin forming the adhesive, as well as the blending amount of the crosslinking agent, reaction temperature, reaction time, etc., the adhesive with the desired characteristics can be prepared according to the purpose. agent. The base resin of the adhesive may be used alone or in combination of two or more. From the viewpoint of transparency, workability, durability, etc., an acrylic adhesive is preferable. The details of the adhesive constituting the adhesive layer are described in, for example, Japanese Patent Application Laid-Open No. 2014-115468, and this specification uses the description of the publication as a reference. The thickness of the adhesive layer can be set to, for example, 10 μm˜100 μm.

[Separate piece 4] The separator 4 can adopt any suitable separator. Specific examples include plastic films, non-woven fabrics, or papers that have been surface-coated with a release agent. Specific examples of the release agent 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 set to, for example, 10 µm to 100 µm.

[Surface Protection Film 5] The surface protection film 5 represents a substrate and an adhesive layer. In this embodiment, the thickness of the surface protection film 5 is, for example, 30 µm or more. The upper limit of the thickness of the surface protection 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 substrate can be made of any appropriate resin film. Examples of materials for forming the resin film include ester-based resins such as polyethylene terephthalate-based resins, cycloolefin-based resins such as norcamphene-based resins, olefin-based resins such as polypropylene, polyamide-based resins, and polycarbonate-based resins. Resins, their copolymer resins, etc. Ester-based resins (especially polyethylene terephthalate-based resins) are preferred.

Any appropriate adhesive can be used for the adhesive forming the adhesive layer. The base resin of the adhesive can be, for example, acrylic resin, styrene resin, silicone resin, urethane resin, or rubber resin.

<Manufacturing method of this embodiment> The manufacturing method of the optical layered body 100 of this embodiment is demonstrated below, and it is a method for manufacturing the optical layered body 100 which has the structure demonstrated above. FIG. 2 is a flow chart showing the schematic steps of the manufacturing method of the optical layered body 100 of this embodiment. As shown in Figure 2, the manufacturing method of this embodiment includes: polarizing film manufacturing step ST1, retardation film bonding step ST2, separator bonding step ST3, multiple times (in this embodiment, 2 times) of separators Peeling and bonding step ST4 and surface protection film bonding step ST5. Hereinafter, each of steps ST1 to ST5 will be described.

[Polarizing film manufacturing step ST1] In the polarizing film production step ST1, a long strip-shaped resin film is used as the original film, and the original film is transported in the longitudinal direction (MD direction) while being immersed in various treatment baths, and dyeing or stretching is performed. processing, etc., to manufacture the elongated strip-shaped polarizer 11 . Then, the long strip-shaped polarizing film 1 is manufactured by bonding the long strip-shaped protective films 12 and 13 to the long strip-shaped polarizer 11 .

[Retardation film bonding step ST2] In step ST2 of attaching the retardation film, the strip-shaped retardation film 2 is attached to one side of the strip-shaped polarizing film 1 (protective film 13 ), thereby manufacturing the strip-shaped polarizing plate 10 . In addition, 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.

[Separate parts bonding step ST3] In the separator bonding step ST3, an adhesive layer forming step is carried out, which involves applying an adhesive while conveying the elongated strip-shaped separator 4 in the longitudinal direction (MD direction), and heating the formed separator 4 with an oven or the like. The applied adhesive is dried to be hardened to form the adhesive layer 3 . Then, the separator 4 is pasted on the strip-shaped polarizing plate 10 through the adhesive layer 3 formed on the strip-shaped separator 4 . Specifically, the adhesive layer 3 side of the strip-shaped separator 4 (separator 4 with adhesive layer 3 attached) is bonded to one side of the strip-shaped polarizing plate 10 (retardation film 2). In this way, the second intermediate M2 in which the polarizing plate 10, the adhesive layer 3, and the separator 4 are laminated is manufactured.

[Separation parts peeling and bonding step ST4] In the separator peeling and attaching step ST4, the separator 4 is peeled off from the adhesive layer 3 (leaving the adhesive layer 3 interposed between the separator 4 and the polarizing plate 10 on the polarizing plate 10 side. , after only peeling off the separator 4), the separator 4 is pasted on the polarizer 10 through the adhesive layer 3. In this embodiment, the separator peeling and attaching step ST4 is performed twice, one of which is the separator replacement step ST41, and the remaining one is the inspection step ST42. However, the present invention is not limited thereto, and among the plurality of separation member peeling and bonding steps ST4, at least one separation member peeling and bonding step ST4 is sufficient if it is the separator replacement step ST41. The manufacturing method of this embodiment repeats the peeling of the separator 4 and the bonding of the separator 4 by including the separator peeling and bonding step ST4 a plurality of times. In other words, even if the separator 4 to be attached is the same as the separator 4 to be peeled off, by repeating the operation of attaching the separator 4 to the polarizing plate 10 in a state where the unevenness of the separator 4 is stretched, it is possible to suppress the separation. curly. In addition, since at least one separator replacement step ST41 is included and the separator replacement step ST41 is used to attach a new separator 4 different from the peeled separator 4, curling can be further suppressed. The specific content of the step ST41 of replacing the separator and the checking step ST42 will be described in sequence below.

(Separate part replacement step ST41) In the separator replacement step ST41 , a new separator 4 different from the peeled separator 4 is pasted on the polarizer 10 through the adhesive layer 3 . Hereinafter, the separator 4 to be peeled off (the separator 4 bonded in the separator bonding step ST3) is appropriately referred to as the "separator 4a", and the new separator 4 to be bonded in the separator replacement step ST41 is appropriately referred to as "separator 4a". The separator 4 is called "separator 4b" to distinguish the two.

Fig. 3 is a side view (viewed from a horizontal direction perpendicular to the conveying direction of each film), which schematically shows an example of the schematic configuration of a device for performing the separator replacement step ST41. The arrows shown in Fig. 3 indicate the conveying direction of each film. In the separator replacement step ST41, the second intermediate M2 produced in the separator attachment step ST3 is wound on the release roller R1 shown in FIG. 3 and arranged on the most upstream side of the device ( The most upstream side in the transport direction of the second intermediate M2). Then, the second intermediate M2 discharged from the discharge roller R1 is conveyed toward the peeling roller R2. The peeling roller R2 peels the separator 4a from the second intermediate M2, and the peeled separator 4a is taken up by the take-up roller R3.

On the other hand, the first intermediate M1 obtained by peeling the separator 4a from the second intermediate M2 by the peeling roller R2 is conveyed toward the bonding roller R4, wherein the first intermediate M1 is the polarizing plate 10 and the adhesive layer 3 laminates. Also, prepare a new separator 4b wound on the discharge roller R5 (that is, a separator 4b that is less prone to unevenness due to the lack of heating for forming the adhesive layer 3) 4b, and the separator 4b will be released from the The roller R5 is released and conveyed toward the bonding roller R4. Then, the separator 4b is bonded to the first intermediate body M1 by the bonding roller R4. That is, through the adhesive layer 3 constituting the first intermediate body M1 , the separator 4 b is attached to the polarizer 10 constituting the first intermediate body M1 . Thereby, the 2nd intermediate body M2 is manufactured, and it is taken up by the take-up roll R6. The separator 4 of the second intermediate M2 released from the discharge drum R1 is the separator 4a, and the separator 4 of the second intermediate M2 taken up by the take-up drum R6 is the separator 4b. In addition, in this embodiment, in the separator replacement step ST41, the elastic modulus (elastic modulus in the TD direction) of the new separator 4b bonded to the polarizing plate 10 is, for example, 6000 [N/mm ² ] or more , on the other hand, the elastic modulus (elastic modulus in the TD direction) of the separator 4a after the step of forming the adhesive layer of the separator bonding step ST3 (that is, after heating) is, for example, less than 6000 [N/mm ² ], The modulus of elasticity 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 to be attached (to be replaced) in the separator replacement step ST41 is not easy to shrink, so curling can be more suppressed . The upper limit of the elastic modulus (elastic modulus in the TD direction) of the separator 4b is not particularly limited, for example, it is not more than 7000 [N/mm ² ], preferably not more than 6500 [N/mm ² ]. The lower limit of the elastic modulus (elastic modulus in the TD direction) of the separator 4a is not particularly limited, for example, it is 5000 [N/mm ² ] or more, preferably 5500 [N/mm ² ] or more. The above modulus of elasticity can be measured, for example, using a tensile testing machine "Autograph" manufactured by Shimadzu Corporation. Specifically, a sample with a width (dimension in the MD direction) of 10 mm and a length (dimension in the TD direction) of 100 mm can be cut out from the separate parts 4a and 4b, and the sample can be mounted on the Autograph at a rate of 50 mm/min. Stretch in the TD direction at the same speed, and calculate the modulus of elasticity according to the force [N] applied to stretch the sample by a predetermined amount.

In this embodiment, in the step ST41 of replacing the separator, the time from peeling the separator 4a to attaching the separator 4b is within 1 minute, preferably within 45 seconds, more preferably within 30 seconds. Specifically, as shown in FIG. 3, when the length of the conveyance path of the first intermediate M1 from the peeling roller R2 to the bonding roller R4 is L and the conveying speed is V, L/V≦1 minute (preferably 45 seconds, more preferably 30 seconds) to set the length L of the conveying path or the conveying speed V. As mentioned above, in this embodiment, the time from peeling off the separator 4a to attaching the separator 4b is short, in other words, the time for the adhesive layer 3 to be exposed is short. Changes due to seasonal influences or daytime or nighttime influences can still suppress the uneven curling that occurs when the polarizer 10 absorbs moisture in the gaseous environment from the side of the adhesive layer 3 and swells.

Hereinafter, the bonding of the first intermediate body M1 and the separator 4b by the bonding roller R4 will be described more specifically. FIG. 4 is an explanatory diagram for explaining the bonding of the first intermediate M1 and the separator 4b by the bonding roller R4. As shown in FIG. 4 , the bonding roller R4 is composed of a pair of opposing first roller R41 and second roller R42. The 1st roller R41 is a roller which contacts the separator 4b and conveys the separator 4b between the 1st roller R41 and the 2nd roller R42. The surface of the first roller R41 is formed of metal (for example, iron). The second roller R42 is a roller that contacts the first intermediate M1 and conveys the first intermediate M1 between the first roller R41 and the second roller R42. The surface of the 2nd roller R42 is formed with resin (for example, rubber).

As shown in FIG. 4 , a straight line (imaginary straight line) passing through the rotation center C1 of the first roller R41 and the rotation center C2 of the second roller R42 is a straight line CL. Let the vector (imaginary vector) which is perpendicular to the straight line CL and faces the delivery side (the right side in FIG. 4 ) of the bonding roller R4 be a vector VC. At this time, the entry angle α of the separator 4b entering the bonding drum R4 means the angle formed by the vector VC and the vector indicating the traveling direction of the separator 4b until it contacts the bonding drum R4. In addition, the entry angle of the first intermediate M1 into the bonding roller R4 (corresponding to the entry angle of the polarizing plate 10 into the bonding roller R4) β means the movement of the vector VC and the first intermediate M1 until it contacts the bonding roller R4 The angle formed by the vector of the direction (equivalent to the traveling direction of the polarizer 10). In this embodiment, both the entry angle α and the entry angle β are set to be smaller than 90°. In Fig. 3, for the sake of convenience, α=90°, β=0° are used to illustrate, but in fact α<90°, β<90° should be 10°<α<80°, more preferably 20°<α<50°. Also, preferably 0°<β<80°, more preferably 0°<β<75°. The conveyability of the first intermediate M1 (polarizing plate 10 ) improves by increasing the angle of entry α.

According to the knowledge of the inventors of the present invention, if the entry angle α of the separator 4b into the laminating roller R4 is large (more than 90°), the negative curl in the TD direction (curl in a concave shape on the side where the separator 4b exists) will be reduced. If the entry angle β of the first intermediate M1 (polarizer 10) into the bonding roller R4 is large (more than 90°), the TD direction will be positive curl (the side where the separator 4b exists is convex. curl) will get bigger. Therefore, curling can be further suppressed by setting α<90° and β<90° as described above.

(check step ST42) The inspection step ST42 of the present embodiment is carried out after the separator replacement step ST41. In the inspection step ST42, the separator 4b is peeled off from the adhesive layer 3 (leaving the adhesive layer 3 interposed between the separator 4b and the polarizing plate 10 on the polarizing plate 10 side), and only the separator is peeled off. After 4b), the polarizing plate 10 is inspected. Then, after inspecting the polarizing plate 10, the peeled separator 4b is attached to the polarizing plate 10 again, thereby restoring it to the original state of the second intermediate body M2.

FIG. 5 is a side view (viewed from a horizontal direction perpendicular to the transport direction of each film), which schematically shows an example of a schematic configuration of an apparatus for performing the inspection step ST42. The arrows shown in Fig. 5 indicate the conveying direction of each film. In the inspection step ST42, the second intermediate M2 manufactured in the separator replacement step ST41 is wound on the release roller R7 shown in FIG. 5 and arranged on the most upstream side of the device (the second intermediate The most upstream side of the conveying direction of body M2). Then, the second intermediate M2 discharged from the discharge roller R7 is conveyed toward the peeling roller R8. The peeling roller R8 peels the separator 4b from the second intermediate M2, and the peeled separator 4b is conveyed toward the bonding roller R9.

On the other hand, the first intermediate M1 obtained by peeling the separator 4b from the second intermediate M2 by the peeling roller R8 is inspected by the inspection device 20, wherein the first intermediate M1 is the polarizing plate 10 and the adhesive layer 3 laminates. The inspection device 20 shown in FIG. 5 is a device for performing transmission inspection, and includes a light source 20a, an imaging mechanism 20b, and a calculation mechanism (not shown). The photographing means 20b of the inspection device 20 receives the light emitted from the light source 20a and transmitted through the first intermediate M1 to form an image, and outputs an electrical signal corresponding to the amount of light as a photographing signal to the calculation mechanism. The calculation mechanism generates the transmission image according to the input shooting signal. Moreover, the calculation mechanism applies the following well-known image processing to the generated transmission image, that is, extracts the luminance value (pixel value) and performs binarization on other pixel areas and different pixel areas, thereby detecting the existence of the first intermediate Defect of body M1 (polarizer 10). In addition, the inspection performed in the inspection step ST42 is not limited to the above-mentioned transmission inspection. Orthogonal polarization inspection can also be used, which is to generate an orthogonal polarization image by passing through the inspection polarizing filter and the light of the first intermediate M1, and detect the presence of the first intermediate M1 (polarized light) according to the orthogonal polarization image. The defect of the plate 10), wherein the polarizing filter is arranged in such a way that the polarization axes of the polarizers 11 included in the polarizing plate 10 are orthogonally polarized. Reflection inspection may also be used, which generates a reflected image by light reflected on the first intermediate M1, and detects defects existing in the first intermediate M1 (polarizer 10) based on the reflected image. In addition, any combination of transmission inspection, cross-polarization inspection, and reflection inspection can be performed.

The first intermediate M1 inspected by the inspection device 20 is conveyed toward the bonding drum R9. Then, the separator 4b is bonded to the first intermediate body M1 again by the bonding roller R9. That is, through the adhesive layer 3 constituting the first intermediate body M1 , the separator 4 b is attached to the polarizer 10 constituting the first intermediate body M1 . Thereby, the 2nd intermediate body M2 is manufactured, and it is taken up by the take-up roll R10. The separator 4 of the second intermediate body M2 discharged from the discharge drum R7 and the separator 4 of the second intermediate body M2 taken up by the take-up drum R10 are both the same separator 4 b. In addition, similarly to the separator replacement step ST41, in the inspection step ST42, the time from peeling the separator 4b with the peeling roller R8 to attaching the separator 4b with the bonding roller R9 is within 1 minute, preferably 45 seconds. Within 30 seconds, preferably within 30 seconds. Also, in the same manner as the separation piece replacement step ST41, in the inspection step ST42, among the pair of opposing rollers constituting the bonding roller R9, the roller that contacts the separation piece 4b and transports the separation piece 4b between the pair of rollers The surface is also formed of metals such as iron. The surface of the roller that contacts the first intermediate M1 and conveys the first intermediate M1 between the pair of rollers is formed of resin (for example, rubber). Also, in the same manner as the separator replacement step ST41, in the inspection step ST42, the angle of entry of the separator 4b into the laminating drum R9 and the angle of entry of the first intermediate M1 (polarizer 10) into the laminating drum R9 β Both are also set to be smaller than 90°. By these, curling can be further suppressed even in the inspection step ST42. The entry angle α of the separator 4b entering the bonding roller R9 and the entry angle β of the first intermediate M1 (polarizer 10) entering the bonding roller R9 are preferably 10°<α<80, more preferably 20°<α<50 °. Also, preferably 0°<β<80°, more preferably 0°<β<75°. The conveyability of the first intermediate M1 (polarizing plate 10 ) improves by increasing the angle of entry α.

[Surface protection film bonding step ST5] The surface protection film sticking step ST5 of this embodiment is implemented after the separator replacement step ST41 (further after the inspection step ST42). In the surface protection film bonding step ST5, the long strip-shaped surface protection film 5 is bonded to the long strip-shaped second intermediate body M2. Specifically, the long strip-shaped surface protection film 5 is bonded to the surface opposite to the side to which the separator 4b is bonded of the polarizing plate 10 constituting the second intermediate body M2. In this way, the long strip-shaped optical layered body 100 is manufactured.

According to the manufacturing method of 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 addition, in the present embodiment, an aspect in which the separator peeling and bonding step ST4 is performed twice is described, but the present invention is not limited thereto, and the separator peeling and bonding step ST4 may be performed three or more times.

In addition, in this embodiment, the aspect in which the separator replacement step ST41 is performed before the inspection step ST42 is described, but the present invention is not limited thereto, and the separator replacement step ST41 may be performed after the inspection step ST42.

In addition, in this embodiment, after inspecting the polarizing plate 10 in the inspection step ST42, the separated separator 4b is bonded to the polarizing plate 10 again, but the present invention is not limited thereto. In the inspection step ST42, a new separator different from the separated separator 4b may be bonded to the inspected polarizing plate 10 similarly to the separator replacement ST41.

Also, in this embodiment, it is described that the inspection step ST42 also serves as the separator peeling and bonding step ST4. Step ST4 of peeling off and attaching separators is carried out. Alternatively, an aspect in which no inspection is performed in the inspection step ST42 (that is, a separator peeling and bonding step ST4 in which only the separator 4 is peeled and bonded) may be employed.

Also, in this embodiment, regarding the step ST3 of attaching the separator to the step ST5 of attaching the surface protection film, they are all described for the state in which each film is in the form of a strip, but the present invention does not Subject to this restriction. For example, the following configuration can also be adopted: after cutting the long strip-shaped polarizing plate 10 produced by the retardation film lamination step ST2 into product size, the separator lamination step ST3~the surface protection film lamination step ST5 is carried out .

In addition, in this embodiment, an example in which the polarizing plate 10 is a laminate of the polarizing film 1 and the retardation film 2 is taken as an example for illustration, but the present invention is not limited thereto. It is also possible to adopt the following aspects: the polarizing plate 10 is a laminated body of the polarizing film 1, the retardation film 2, and other components; A form of a laminate of elements; or a form in which only the polarizing film 1 exists on the polarizing plate 10 .

In the following, an example of the results of evaluating the curl of the optical layered body 100 produced by the production method (Example) of this embodiment shown in FIG. An example of the result of curling of the laminate will be described. The optical laminates 100 produced in Examples and Comparative Examples all have a structure in which layers are laminated in the following order. (1) Surface protection film 5 (substrate: PET・thickness 38µm, adhesive layer: acrylic adhesive・thickness 10µm) (2) Cycloolefin-based protective film 12 (total thickness 32µm) with hard coat layer (thickness 7µm) (3) Adhesive (4) Polyvinyl alcohol-based polarizer 11 (thickness 12µm) (5) Adhesive (6) Triacetate-based protective film 13 (thickness 25µm) (7) Adhesive (8) Polymerizable liquid crystal 1/2 wavelength plate 2 (thickness 2.5µm) (9) Acrylic adhesive layer 3 (thickness 20µm) (10) Separator 4 (PET・thickness 38µm) In addition, in the optical laminate 100 produced in the embodiment, in the inspection step ST42, the same separator 4 as the peeled separator 4 was attached to the inspected polarizing plate 10 (not separated in the inspection step ST42). Reposting of Item 4).

Fig. 6 is an explanatory diagram for explaining an evaluation method of curl. As shown in FIG. 6( a ), in the embodiment, a plurality of rectangular optical laminates 100S of product size (length 148mm×width 70mm) are cut out along the TD direction of the elongated optical laminate 100 . In FIG. 6( a ), three optical layered bodies 100S are shown for convenience, but actually, ten optical layered bodies 100S are cut out along the TD direction of one optical layered body 100 . This procedure was carried out for a plurality of optical layered bodies 100 to obtain a total of 500 optical layered bodies 100S. Then, curl was evaluated about 100 sheets randomly selected from 500 sheets of the optical layered body 100S. In addition, as shown in FIG. 6( b ), when cutting the optical layered body 100S, the MD direction of the optical layered body 100 (the direction corresponding to the absorption axis of the polarizer 11 ) is relative to the length of the optical layered body 100S. The side and the short side are cut obliquely at 45°.

As shown in FIG. 6( c ), when evaluating the curl, the underside of the optical layered body 100S is convex (in such a way that the warping of the four corners of the optical layered body 100S is vertically upward), The optical layered body 100S was placed on the flat mounting table 30, and the distance H in the vertical direction from the upper surface of the mounting table 30 to the corners was measured for each of the four corners of the optical layered body 100S. The distance H is measured by providing a ruler extending in the vertical direction near the corner of the optical laminate 100S, and reading the scale of the ruler with the naked eye. When the optical layered body 100S is placed on the mounting table 30 so that the lower side is convex, it is positive that the side of the optical layered body 100S where the separator 4 is present is lower (the side where the surface protection film 5 is placed is upper). Curl, and calculate the measured distance H directly as the curl value. On the other hand, when the lower side of the optical layered body 100S is placed on the mounting table 30 in a convex manner, the side of the optical layered body 100S where the separator 4 is present is on the upper side (the side where the surface protection film 5 is present is on the lower side). ) is a negative curl, and the value obtained by multiplying the measured distance H by -1 is calculated as the curl value.

Next, as shown in FIG. 6( d ), the separator 4 is peeled off from the optical layered body 100S. Then, for the laminate (the laminate of the first intermediate M1 and the surface protection film 5 ) after the separator 4 was peeled off, the curl values of the four corners were also calculated in the same procedure as above.

In addition, when the curl values of the four corners of the optical layered body 100S and the curl values of the four corners of the laminate after peeling off the separator 4 all satisfy the condition of -5mm≦curl value≦5mm, it is evaluated as acceptable, and it is not acceptable. Satisfied conditions are evaluated as unqualified. Also about the comparative example, the curl value was calculated by the same procedure as the example demonstrated above, and it judged as pass or fail.

如表1所示，在比較例中，100片光學積層體中有44片合格(合格率44%)，相對於此，在實施例中，100片光學積層體中有64片合格(合格率44%)，可知捲曲受抑制。 Table 1 shows the evaluation results of curling in Examples and Comparative Examples. [Table 1]

As shown in Table 1, in the comparative example, 44 out of 100 optical laminates were qualified (44%), while in the examples, 64 out of 100 optical laminates were qualified (44%). 44%), it can be seen that curling is suppressed.

1: Polarizing film 10: polarizer 11: Polarizer 12,13: Protective film 2: Retardation film 20: Check device 20a: light source 20b: Shooting agency 3: Adhesive layer 30: Carrying table 4,4a,4b: Separate parts 5: Surface protection film 100,100S: optical laminate α: The entry angle of the separating part into the bonding drum β: The entry angle of the intermediate body into the laminating drum C1: Rotation center of the first roller C2: Rotation center of the second drum CL: A straight line passing through the rotation center of the first roller and the second roller (imaginary straight line) H: The distance in the vertical direction from the upper surface of the mounting table to the corner L: Length of conveying path M1: the first intermediate M2: the second intermediate MD: The conveying direction of the strip-shaped optical laminate R1, R5, R7: release roller R2, R8: Peeling roller R3, R6, R10: take-up drum R4, R9: Laminating roller R41: 1st roller R42: 2nd roller ST1, ST1': Manufacturing steps of polarizing film ST2, ST2': Retardation film bonding step ST3, ST3': Laying steps of separated parts ST4: Separate parts peeling and bonding steps ST4', ST42: Inspection steps ST41: Separation parts replacement steps ST5, ST5': Surface protection film bonding step TD: The direction perpendicular to the conveying direction of the strip-shaped optical laminate V: conveying speed VC: The vector (imaginary vector) perpendicular to the straight line CL and facing the delivery side of the bonding roller

FIG. 1 is a cross-sectional view schematically showing a schematic configuration of an optical layered body manufactured by a manufacturing method according to an embodiment of the present invention. Fig. 2 is a flow chart showing schematic steps of a method for manufacturing an optical laminate according to an embodiment of the present invention. Fig. 3 is a side view (viewed from a horizontal direction orthogonal to the conveying direction of each film), which schematically shows an example of the general configuration of the device for performing the separator replacement step ST41 shown in Fig. 2 . FIG. 4 is an explanatory diagram for explaining the bonding of the first intermediate M1 and the separator 4b using the bonding roller R4 shown in FIG. 3 . 5 is a side view (viewed from a horizontal direction perpendicular to the conveying direction of each film), which schematically shows an example of a schematic configuration of a device for performing the inspection step ST42 shown in FIG. 2 . Fig. 6 is an explanatory diagram for explaining an evaluation method of curl. Fig. 7 is a flow chart showing an example of schematic steps of a conventional method for producing an optical laminate.

ST1: Manufacturing steps of polarizing film

ST2: Retardation film bonding step

ST3: Separation parts bonding step

ST4: Separate parts peeling‧bonding step

ST41: Separation parts replacement steps

ST42: Inspection steps

ST5: Lamination steps of surface protection film

Claims (10)

A method of manufacturing an optical laminate, comprising the following steps: The step of attaching the separator to the polarizer through the adhesive layer formed on the separator; and A plurality of steps of peeling and attaching the separator, which is to attach the separator to the polarizing plate through the adhesive layer after peeling the separator from the adhesive layer; Among the multiple times of peeling and bonding steps of the aforementioned separator, at least one of the aforementioned steps of peeling and bonding of the aforementioned separator is a step of replacing the separator. A new separator different from the separator was bonded to the aforementioned polarizing plate. The method for manufacturing an optical laminate according to Claim 1, wherein among the plurality of steps of peeling and bonding the separator, at least one step of peeling and bonding the separator is performed after the step of replacing the separator. The method for manufacturing an optical laminate according to claim 1 or 2, wherein among the plurality of steps of peeling and bonding the separator, at least one of the steps of peeling and bonding the separator is also used as an inspection step, and the inspection step is After peeling off the separator, the aforementioned polarizing plate was inspected. The method of manufacturing an optical laminate according to claim 1 or 2, which includes a step of attaching a surface protection film. The step of attaching a surface protection film is to attach a surface protection film to the polarizer after the step of replacing the separator. The method for manufacturing an optical laminate according to claim 1 or 2, wherein the step of adhering the separator includes a step of forming an adhesive layer. The step of forming the adhesive layer is to apply an adhesive to the separator, and apply the coated The adhesive is heated to harden to form the aforementioned adhesive layer. The method for manufacturing an optical laminate according to Claim 5, wherein in the step of replacing the separating member, the elastic modulus of the new separating member to be bonded to the polarizing plate is higher than that of the separating member after the adhesive layer forming step modulus of elasticity. The method of manufacturing an optical laminate according to claim 1 or 2, wherein in the step of peeling and attaching the separator, the time from peeling the separator to attaching the separator is within 1 minute. The method for manufacturing an optical laminate according to claim 1 or 2, wherein in the step of peeling and bonding the separator, the separator and the polarizing plate are bonded by a bonding roller; The entry angle of the separator into the bonding roller is less than 90°, and the entry angle of the polarizing plate into the bonding roller is less than 90°. The method of manufacturing an optical laminate according to claim 8, wherein the bonding roller is composed of a first roller contacting the separator and a second roller contacting the polarizing plate, and The surface of one of the first roller and the second roller is made of resin, and the surface of the other is made of metal. The method for manufacturing an optical laminate according to claim 9, wherein the surface of the first roller is made of metal, The surface of the aforementioned second roller is formed of resin.

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