Manufacturing method of optical laminate and manufacturing apparatus of optical laminate

Abstract

To provide a manufacturing method for an optical laminate and a manufacturing apparatus for an optical laminate, by which the temperature unevenness in a width direction on a surface or a roll can be reduced and the problem of the quality of a bonding film can be reduced.SOLUTION: A manufacturing method for an optical laminate is a manufacturing method for an optical laminate including at least one layer including an optical film and includes a bonding step of forming a bonding film from two different films through an adhesive of an energy line activation type, and an activating step of irradiating the bonding film on the roll with an energy line while bringing the bonding film into contact with the roll so as to activate the adhesive. The roll includes a heat medium flow path for feeding a heat medium in the roll. The activating step is performed while the heat medium is fed to the heat medium flow path and the roll is maintained in the range satisfying Expression (1).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method and an apparatus for producing an optical laminate. [Background technology]

[0002] In the manufacture of optical laminates such as polarizing plates, the optical films constituting the optical laminate are laminated with an energy ray-activated adhesive, and then the resulting laminated film is subjected to an activation treatment while being transported. The activation treatment is performed by irradiating the laminated film passing over a roll with energy rays. The irradiation of the energy rays is usually performed while cooling the laminated film on a cooled roll so as to prevent quality problems of the laminated film such as deformation of the laminated film and uneven curing. Conventionally, as a method for cooling a roll, for example, as disclosed in JP 2019-3210 A (Patent Document 1), a method of flowing a heat medium inside the roll has been known. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-3210 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, when a heat transfer medium is caused to flow through a roll as in the conventional method, there is a risk of temperature unevenness occurring in the width direction of the roll surface. The temperature unevenness in the width direction of the roll surface causes the reaction speed of the adhesive in the width direction of the laminated film to be non-uniform, which may cause problems with the quality of the laminated film.

[0005] Therefore, an object of the present disclosure is to provide a method and an apparatus for manufacturing an optical laminate that reduce temperature unevenness in the width direction of the surface of a roll and reduce problems with the quality of the laminated film. [Means for solving the problem]

[0006] To solve the above problems, a method for manufacturing an optical laminate according to one aspect of the present disclosure is a method for manufacturing an optical laminate having at least one layer made of an optical film, a laminating step of laminating two different films via an energy ray-curable adhesive to form a laminated film, an activation treatment step of irradiating the laminated film with energy rays on the roll while bringing the laminated film into contact with the roll to perform activation treatment of the adhesive, and includes the roll is provided with a heat medium flow path for flowing a heat medium therein, the activation treatment step is performed while maintaining the roll within a range satisfying the following formula (1): 0 < X1 / X2 ≤ 3.5 Formula (1): 0 < X1 / X2 ≤ 3.5 (X1: the amount of heat (KJ) of the heat medium in the roll generated from the maximum temperature difference in the width direction of the roll surface, X2: the heat capacity (KJ / K) of the heat medium in the roll) Here, in this specification, X1 is a value obtained by subtracting the amount of heat applied to the heat medium in the roll at the minimum temperature in the width direction of the roll surface from the amount of heat applied to the heat medium in the roll at the maximum temperature in the width direction of the roll surface.

[0007] According to the above aspect, since the activation treatment step is performed while maintaining the roll within the range of formula (1): 0 < X1 / X2 ≤ 3.5, temperature unevenness in the width direction of the roll surface can be reduced, the reaction rate of the adhesive can be made substantially uniform in the width direction of the laminated film, and quality problems of the laminated film can be reduced.

[0008] Preferably, in one embodiment of the method for manufacturing an optical laminate,

[0009] the activation treatment step further satisfies the following formula (2): X1 / (3.5×Sc) ≤ X2 / Sc ≤ V wherein Formula (2): X1 / (3.5×Sc) ≤ X2 / Sc ≤ V (Sc: specific heat of heat transfer medium (KJ / K L), V: maximum capacity of heat transfer medium in roll (L)) This includes flowing the heat transfer medium within a range that satisfies the above.

[0010] According to the above embodiment, the activation process includes flowing heat transfer medium within the range that satisfies formula (2): X1 / (3.5×Sc)≦X2 / Sc≦V. Therefore, a sufficient amount of heat transfer medium can be flowed, and the temperature unevenness in the width direction of the roll surface can be further reduced, and the quality problem of the laminated film can be further reduced.

[0011] Preferably, in one embodiment of the method for producing an optical laminate, the activation treatment step further includes adjusting the temperature distribution in the width direction of the surface of the roll to 3° C. or less.

[0012] According to the above embodiment, the activation treatment process includes reducing the temperature distribution in the width direction of the roll surface to 3°C or less, thereby further reducing the temperature unevenness in the width direction of the roll surface and further reducing problems with the quality of the laminated film.

[0013] Preferably, in one embodiment of the method for producing an optical laminate, the activation treatment step further includes discharging air within the roll to the outside of the roll from a downstream side of a heat transfer medium flow path.

[0014] According to the above embodiment, the activation treatment process includes discharging the air in the roll from the downstream side of the heat transfer medium flow path to the outside of the roll, thereby further reducing the temperature unevenness in the width direction of the roll surface, and further reducing problems with the quality of the laminated film.

[0015] In addition, the manufacturing apparatus for an optical laminate according to one embodiment of the present disclosure includes: An apparatus for producing an optical laminate having at least one layer made of an optical film, comprising: a lamination device that laminates two different films together with an energy ray activated adhesive to form a laminated film; A roll that comes into contact with the laminated film and has a heat medium flow path therein through which a heat medium flows; An activation treatment device that irradiates an energy beam onto the bonding film on the roll to perform an activation treatment on the adhesive, When performing the activation treatment on the adhesive by the activation treatment device, the roll is Formula (1): 0 < X1 / X2 ≦ 3.5 (X1: The amount of heat medium in the roll generated from the maximum temperature difference in the width direction of the roll surface (KJ), X2: The heat capacity of the heat medium in the roll (KJ / K)) A control device that controls to maintain within a range that satisfies is provided.

[0016] According to the above aspect, since the control device controls to maintain the roll within a range that satisfies Formula (1): 0 < X1 / X2 ≦ 3.5, the temperature unevenness in the width direction of the roll surface can be reduced, the reaction rate of the adhesive can be made substantially uniform in the width direction of the bonding film, and quality problems of the bonding film can be reduced.

[0017] Preferably, in one embodiment of a manufacturing apparatus for an optical laminate, When performing the activation treatment on the adhesive by the activation treatment device, the control device further Formula (2): X1 / (3.5×Sc) ≦ X2 / Sc ≦ V (Sc: Specific heat of the heat medium (KJ / K·L), V: Maximum capacity of the heat medium in the roll (L)) controls to flow the heat medium within a range that satisfies.

[0018] According to the above embodiment, since the control device controls to flow the heat medium within a range that satisfies Formula (2): X1 / (3.5×Sc) ≦ X2 / Sc ≦ V, a sufficient amount of heat medium can be flowed, the temperature unevenness in the width direction of the roll surface can be further reduced, and quality problems of the bonding film can be further reduced.

[0019] Preferably, in one embodiment of a manufacturing apparatus for an optical laminate, when performing the activation treatment on the adhesive by the activation treatment device, the control device further controls to make the temperature distribution in the width direction of the roll surface 3.5°C or less.

[0020] According to the above embodiment, when the control device performs the activation process of the adhesive using the activation treatment device, the control device further controls the temperature distribution in the width direction of the roll surface to 3°C or less, thereby further reducing the temperature unevenness in the width direction of the roll surface and further reducing problems with the quality of the laminated film.

[0021] Preferably, in one embodiment of the optical laminate manufacturing apparatus, the roll further has an air vent passage downstream of the heat transfer medium passage, the air vent passage communicating with the heat transfer medium passage and discharging air within the heat transfer medium passage to the outside of the roll.

[0022] According to the embodiment, the roll has an air vent passage communicating with the heat medium passage, so that the heat medium can be made to flow into the roll while the air in the roll is discharged to the outside of the roll, thereby reducing temperature unevenness in the width direction of the roll surface, making the reaction speed of the adhesive in the width direction of the bonded film approximately uniform, and reducing problems with the quality of the bonded film. Effect of the Invention

[0023] According to the method and apparatus for producing an optical laminate according to one aspect of the present disclosure, temperature unevenness in the width direction of the surface of the roll can be reduced, thereby reducing problems with the quality of the laminated film. [Brief description of the drawings]

[0024] [Figure 1] 1 is a schematic diagram showing a first embodiment of an apparatus for producing an optical laminate. [Figure 2A] A cross-sectional view taken along the axis of a 150φ acrylic double tube roll. [Figure 2B] 2B is a cross-sectional view taken along line AA in FIG. 2A. [Figure 3A] FIG. 1 is a cross-sectional view taken along the axis of a roll of 150φ acrylic single tube; [Figure 3B] 3B is a cross-sectional view taken along line AA in FIG. 3A. [Figure 4] 1 is a graph showing the relationship between the flow velocity (m / s) of the heat medium and the height (mm) of the air layer. [Diagram 5] FIG. 1 is a diagram showing the scale-up of an acrylic double-walled tube roll carried out in an example. [Figure 6] FIG. 2 is a plan view of the roll, illustrating positions a to e in the width direction of the surface of the roll. [Figure 7] 1 is a graph showing temperatures at positions a to e in the width direction of a roll when a 200Φ double-tube roll is used. [Figure 8] 1 is a graph showing temperatures at positions a to e in the width direction of a roll when a 250Φ single tube roll is used. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Hereinafter, a method and an apparatus for producing an optical laminate according to one aspect of the present disclosure will be described in detail with reference to the illustrated embodiments. Note that the drawings include some schematic views and may not reflect actual dimensions or proportions.

[0026] (First embodiment) (Device) Fig. 1 is a schematic diagram showing a first embodiment of an apparatus for producing an optical laminate. As shown in Fig. 1, the apparatus for producing an optical laminate 1 includes a laminating device 5 for laminating a first film 31 and a second film 32, which are different from each other, to form a laminated film 33, a roll 12 in contact with the laminated film 33, an activation treatment device 13 for irradiating the laminated film 33 with energy rays to form an optical laminate 34, and a control device 6 for controlling the roll 12.

[0027] In this embodiment, the first film 31 is an optical film such as a polarizing film, the second film 32 is a transparent film, and the optical laminate 34 is a polarizing plate. These films are transported in the direction indicated by the arrow in FIG.

[0028] The optical film is a resin film exhibiting optical properties, such as a polarizing film, a retardation film, etc. The polarizing film is formed, for example, by dyeing a uniaxially stretched polyvinyl alcohol film with iodine or a dichroic dye, and then treating it with boric acid. Examples of the transparent film include thermoplastic resins such as amorphous polyolefin-based resin films, polyester-based resin films, acrylic-based resin films, polycarbonate-based resin films, polysulfone-based resin films, and alicyclic polyimide-based resin films. Examples of the transparent film include resin films with low moisture permeability. Examples of the transparent film further include cellulose acetate-based resin films such as triacetyl cellulose films and diacetyl cellulose films.

[0029] The laminating device 5 has an adhesive applicator 11 that applies an adhesive to one side of the first film 31, and a first laminating roll 21 and a second laminating roll 22 that overlap the first film 31 and the second film 32 and laminate them via the adhesive. The adhesive is an energy ray activated adhesive.

[0030] For example, an epoxy resin that does not contain an aromatic ring in the molecule is used as the adhesive from the viewpoints of weather resistance, refractive index, cationic polymerization, etc. For example, a hydrogenated epoxy resin, an alicyclic epoxy resin, an aliphatic epoxy resin, etc. is used as the epoxy resin. A polymerization initiator, for example, a photo-cationic polymerization initiator for polymerization by irradiation with active energy rays, a thermal cationic polymerization initiator for polymerization by heating, and other additives (sensitizer, etc.) are added to the epoxy resin.

[0031] The roll 12 is driven to rotate around its axis, and conveys the laminated film 33 while contacting the surface of the roll 12. That is, the roll 12 makes the temperature unevenness in the width direction approximately uniform when the laminated film 33 is irradiated with energy rays from the activation treatment device 13. The roll 12 has a heat medium flow path for flowing a heat medium therein, and the laminated film 33 is cooled by the heat medium flowing through the heat medium flow path. The heat medium is, for example, water. The roll 12 may be composed of, for example, a double tube of an outer tube and an inner tube, and in this case, the heat medium flow path is formed between the outer tube and the inner tube, and is formed in a circular ring shape when viewed from the axial direction of the roll 12. Alternatively, the roll 12 may be composed of, for example, a single tube of an outer tube, and in this case, the heat medium flow path is formed inside the outer tube.

[0032] The activation treatment device 13 is disposed facing the roll 12. The activation treatment device 13 irradiates the bonding film 33 on the roll 12 with energy rays to perform an activation treatment on the adhesive. That is, the activation treatment device 13 polymerizes and cures the adhesive by irradiating energy rays. In this way, the optical laminate 34 formed by the activation treatment of the activation treatment device 13 is wound up by the winding roll 20. The activation treatment device 13 uses, for example, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a chemical lamp, a black light lamp, a microwave-excited mercury lamp, a metal halide lamp, etc., which have a light emission distribution at a wavelength of 400 nm or less.

[0033] When the activation treatment device 13 performs the activation treatment on the adhesive, the control device 6 controls the roll 12 to be maintained within a range satisfying the formula (1): 0 < X1 / X2 ≦ 3.5. X1 is the amount of heat (KJ) of the heat medium in the roll 12 generated from the maximum temperature difference in the width direction of the surface of the roll 12. That is, X1 is a value obtained by subtracting the amount of heat applied to the heat medium in the roll 12 at the minimum temperature in the width direction of the surface of the roll 12 from the amount of heat applied to the heat medium in the roll 12 at the maximum temperature in the width direction of the surface of the roll 12. X2 is the heat capacity (KJ / K) of the heat medium in the roll 12. The calculation method of the formula (1) will be described later. Specifically, the control device 6 is composed of a central processing unit. The control device 6 controls, for example, by adjusting the flow rate of the heat medium in the roll 12, the flow rate, temperature, or the amount of the heat medium in the roll 12, to be maintained within a range satisfying the formula (1). According to this, since the control device 6 controls the roll 12 to be maintained within the range of the formula (1), the temperature unevenness in the width direction of the surface of the roll 12 can be reduced, the reaction rate of the adhesive can be made substantially uniform in the width direction of the bonding film 33, and quality problems of the bonding film 33 can be reduced.

[0034] Preferably, when the activation treatment of the adhesive is performed by the activation treatment device 13, the control device 6 further controls the flow of the heat medium within a range that satisfies formula (2): X1 / (3.5×Sc)≦X2 / Sc≦V. Sc is the specific heat of the heat medium (KJ / K·L). V is the maximum capacity (L) of the heat medium in the roll 12. The lower limit value (X1 / (3.5×Sc)) of formula (2) is the capacity of the heat medium required when the maximum temperature difference in the width direction of the surface of the roll 12 is 3.5 K. A method of calculating formula (2) will be described later. This allows a sufficient amount of heat medium to flow through the roll 12, further reducing temperature unevenness in the width direction of the surface of the roll 12 and further reducing problems with the quality of the laminated film.

[0035] When the activation treatment of the adhesive is performed by the activation treatment device 13, the control device 6 further controls the temperature distribution (maximum temperature difference) in the width direction of the surface of the roll 12 to be preferably 3.5° C. or less, more preferably 3° C. or less, and even more preferably 2° C. or less. In other words, the control device 6 preferably controls the difference between the maximum temperature in the width direction of the surface of the roll 12 and the minimum temperature in the width direction of the surface (outer surface) of the roll 12 to be 3.5° C. or less, and more preferably 3° C. or less. According to this, the temperature unevenness in the width direction of the surface of the roll 12 can be further reduced, and problems with the quality of the laminated film 33 can be further reduced.

[0036] Preferably, the roll 12 further has an air vent passage communicating with the heat medium passage and discharging the air in the heat medium passage to the outside of the roll. This allows the heat medium to flow in the roll 12 while discharging the air in the roll 12 to the outside of the roll. This reduces temperature unevenness in the width direction of the surface of the roll 12, makes the reaction speed of the adhesive in the width direction of the bonding film 33 approximately uniform, and reduces problems with the quality of the bonding film 33. The air vent passage may discharge not only air but also the heat medium. The air vent passage is preferably provided downstream of the heat transfer medium passage. The roll 12 preferably has a plurality of air vent passages. When the roll 12 has a plurality of air vent passages, the air vent passages are preferably provided at equal intervals around the rotation axis of the roll 12. The temperature of the outer surface of the roll 12 can be adjusted by the heat transfer medium flowing inside the roll 12. The roll 12 having an air vent passage can easily increase the flow rate of the heat transfer medium flowing inside the roll 12, and therefore, it is easy to uniformly adjust the temperature of the outer surface.

[0037] The manufacturing apparatus of the present disclosure is not limited to the above-mentioned embodiment, and the design can be modified within the scope of the present disclosure. For example, the optical film may be a single layer or a laminate. The type of the optical film is not particularly limited as long as it is a film that exhibits optical properties. The obtained optical laminate may have at least one layer made of an optical film. In other words, the optical laminate may have a film that does not exhibit optical properties, as long as it exhibits optical properties. For example, it may be an optical film such as a retardation film, a protection film, or the above-mentioned polarizing film, or an optical laminate in which these films and thermoplastic resins are laminated. The manufacturing apparatus may have two or more activation treatment devices and two or more rolls. In the manufacturing apparatus, the activation treatment devices may be provided so as to face one roll.

[0038] (Production method) Next, one embodiment of a method for producing an optical laminate will be described with reference to FIG. First, the first film 31 and the second film 32 are laminated together via an energy ray-activated adhesive to form a laminated film 33. This is called a lamination process. Thereafter, while the laminated film 33 is in contact with the roll 12, the laminated film 33 is irradiated with energy rays on the roll 12 to activate the adhesive. This is called an activation process. That is, in the activation treatment step, while flowing a heat medium through the heat medium flow path, the roll 12 is maintained within the range satisfying the formula (1): 0 < X1 / X2 ≦ 3.5 and the step is carried out. Since the activation treatment step is carried out while maintaining the roll 12 within the range of the formula (1), it is possible to reduce the temperature unevenness in the width direction of the surface of the roll 12, make the reaction rate of the adhesive substantially uniform in the width direction of the bonding film 33, and reduce the quality problems of the bonding film 33.

[0039] Preferably, the activation treatment step further includes flowing a heat medium within the range satisfying the formula (2): X1 / (3.5×Sc) ≦ X2 / Sc ≦ V. According to this, a sufficient amount of heat medium can be flowed through the roll 12, the temperature unevenness in the width direction of the surface of the roll 12 can be further reduced, and the quality problems of the bonding film 33 can be further reduced.

[0040] The activation treatment step further includes making the temperature distribution in the width direction of the surface of the roll 12 preferably 3.5°C or less, more preferably 3°C or less, and still more preferably 2°C or less. According to this, the temperature unevenness in the width direction of the surface of the roll 12 can be further reduced, and the quality problems of the bonding film 33 can be further reduced. In the above activation treatment step, when irradiating the bonding film 33 with energy rays a plurality of times, usually, an energy ray irradiation is carried out using a manufacturing apparatus equipped with two or more activation treatment apparatuses. The energy ray irradiation may be carried out while passing through one roll facing two or more activation treatment apparatuses, or using an apparatus having two or more rolls facing one or more activation treatment apparatuses, and passing the bonding film through a plurality of rolls. In this implementation correspondence, further, a step of irradiating the bonding film 33 obtained by the activation treatment with energy rays may be included, or a heating step may be included on the bonding film 33 obtained by the activation treatment. According to this, the activation treatment of the adhesive can be carried out more reliably. In this implementation correspondence, the step of irradiating the bonding film 33 obtained by the activation treatment with energy rays is different from the energy ray irradiation in the above activation treatment step in that it is carried out on a roll having a configuration different from that of the roll in the above activation treatment step. The heating temperature in the above step can be appropriately set depending on the type and thickness of the film and adhesive constituting the optical laminate, but is usually 20 to 90°C, preferably 30 to 70°C, and more preferably 40 to 60°C.

[0041] Preferably, the activation process further includes discharging the air in the roll 12 to the outside of the roll 12. This can further reduce temperature unevenness in the width direction of the surface of the roll 12 caused by the air in the roll 12, and can further reduce problems with the quality of the laminated film 33. Preferably, the air in the roll 12 is discharged to the outside of the roll 12 from the downstream side of the heat transfer medium flow path.

[0042] The manufacturing method of the present disclosure is not limited to the above-described embodiment, and can be modified without departing from the scope of the present disclosure. For example, the manufacturing method of the present disclosure is not limited to being realized by the manufacturing apparatus 1 of FIG. 1, and may be realized by other different apparatuses.

[0043] (Example) Next, an embodiment will be described.

[0044] (First film) A long polyvinyl alcohol [PVA] film (thickness 20 μm, average degree of polymerization approximately 2400, saponification degree 99.9 mol % or more) was uniaxially stretched approximately six times by dry stretching, and then, while maintaining the tension, was immersed in pure water at 40°C for 40 seconds. Next, this film was dyed by immersing it for 30 seconds in an aqueous dye solution at 28° C. in which the mass ratio of iodine / potassium iodide / water was 0.044 / 5.7 / 100. Next, the dyed film was immersed in an aqueous boric acid solution at 70° C., in which the mass ratio of potassium iodide / boric acid / water was 11.0 / 6.2 / 100, for 120 seconds, to perform a crosslinking treatment. The crosslinked film was then washed with pure water at 8° C. for 15 seconds, and then dried at 60° C. for 50 seconds and then at 75° C. for 20 seconds while maintaining a tension of 300 N / m. In this way, a 7 μm-thick polarizing film (width 1300 mm) in which iodine was adsorbed and oriented on the PVA film was obtained. A cycloolefin resin film (COP, Zeon Corporation ZF-14, no UV absorption characteristics, thickness 13 μm) was prepared as a protective film. A water-based adhesive was injected between the obtained polarizing film and the cycloolefin resin film, and they were bonded together using a nip roll. The obtained laminate was dried at 60° C. for 2 minutes while maintaining the tension at 430 N / m, to obtain a first film including a polarizing film layer (hereinafter also referred to as a "polarizer layer") and a protective layer disposed on one side of the polarizer layer. The thickness of the first film was 20 μm. The above water-based adhesive was prepared by adding 3 parts by mass of carboxyl group-modified polyvinyl alcohol (Kuraray Co., Ltd.; Kuraray Poval (registered trademark) KL318) and 1.5 parts by mass of water-soluble polyamide epoxy resin (Taoka Chemical Co., Ltd.; Sumirez Resin (registered trademark) 650; aqueous solution with a solid content of 30%) to 100 parts by mass of water.

[0045] (Second film) A long transparent film (width 1340 mm) made of a polyethylene terephthalate film having a thickness of 38 μm was prepared. The composition for the alignment layer was applied to one side of the transparent film so as to have a film thickness of 3 μm, and the accumulated light amount was 20 mJ / cm 2 The alignment layer was formed by irradiating the film with ultraviolet light. The above-mentioned composition for the alignment layer was prepared by mixing 2-phenoxyethyl acrylate, tetrahydrofurfuryl acrylate, dipentaerythritol triacrylate, and bis(2-vinyloxyethyl) ether in a ratio of 1:1:4:5, and adding LUCIRIN (registered trademark) TPO as a polymerization initiator in a ratio of 4% based on the total mass of the obtained mixture. A liquid crystal composition containing a polymerizable nematic liquid crystal compound (RMM28B, manufactured by Merck) was applied onto the formed alignment layer by die coating. The liquid crystal composition was prepared using a mixed heat medium prepared by mixing methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), and cyclohexanone (CHN) with a boiling point of 155° C. in a mass ratio (MEK:MIBK:CHN) of 35:30:35 as a solvent. The liquid crystal composition was then coated on the alignment layer so that the solid content per 100 g of the liquid crystal composition was 1 to 1.5 g. After the liquid crystal composition was applied onto the alignment layer, the resulting coating layer was dried at a drying temperature of 75°C for 120 seconds. The liquid crystal compound was then polymerized and hardened by ultraviolet (UV) irradiation. Thus, a second film was obtained that was composed of a retardation layer, an alignment layer, and a transparent film. This retardation layer satisfied the relationship nz>nx=ny and was a positive C layer. The total thickness of the retardation layer and the alignment layer was 4 μm.

[0046] (Method for producing composition for forming coating layer) The coating layer-forming composition used was an adhesive obtained by mixing the materials in the ratios shown in the following Table 1. In Table 1, the ratio of each material is expressed in parts by mass.

[0047] [Table 1]

[0048] Details of the compounds in Table 1 are as follows: Compound 1: [ka] 3',4'-Epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate ("CEL2021P" manufactured by Daicel Chemical Industries, Ltd., alicyclic diepoxy)

[0049] Compound 2: [ka] Neopentyl glycol diglycidyl ether (NPGDGE) ("EX-211" manufactured by Nagase ChemteX Corporation, diepoxy)

[0050] Compound 3: [ka] 2-Ethylhexyl glycidyl ether (EHGE) (Tokyo Chemical Industry Co., Ltd., monoepoxy)

[0051] Initiator: Cationic initiator SP-500 (2.25 parts solids) manufactured by ADEKA Corporation Sensitizer: Sensitizer DEN manufactured by Kawasaki Chemical Industries, Ltd. Leveling agent: ADEKA Corporation's leveling agent KRM-430

[0052] (First Manufacturing Example of Optical Laminate) While the first film (width 1340 mm) and the second film (width 1340 mm) were continuously transported, the polarizer layer of the first film and the retardation layer of the second film were subjected to corona treatment. While the first film and the second film were still transported, the above-mentioned adhesive was applied to the corona-treated surface of the first film using a coater (bar coater), and then the polarizer layer of the first film and the retardation layer of the second film were superimposed and passed between a pair of laminating rolls to obtain a laminated film having a layer structure of the first film / coating layer / second film.

[0053] The laminated film obtained was transported at a speed of 10 m / min, and the integrated light dose on the laminated film was 250 mJ / cm 2 The adhesive was cured by irradiating it with ultraviolet light from an activation treatment device while it was in close contact with a roll so that the ultraviolet ray concentration was (UVB) . An optical laminate was obtained by using a high pressure mercury lamp manufactured by iGraphics Co., Ltd. as the activation treatment device.

[0054] (Calculation method of the above formula (1) and formula (2)) Next, the calculation method of the above formula (1) and formula (2) will be described below based on a specific example.

[0055] 1. Flow rate of the roll and heat transfer medium inside the roll (1) A 200φ double tube roll and a 250φ single tube roll were used. The 200φ double-tube roll is composed of an outer tube and an inner tube made of rolled steel (SM490A), with a heat transfer medium flowing between the outer tube and the inner tube. The roll diameter is 200 mm, and the roll length is 1350 mm. The 250φ single-tube roll is made of a single tube made of rolled steel (SM490A), and the heat transfer medium flows inside the single tube. The roll diameter is 250 mm, and the roll length is 1200 mm. Then, the cross-sectional areas of the flow passages in these rolls were obtained. For a 200Φ double tube roll, (0.089×0.089×π)-(0.075×0.075×π)=0.00721m 2 It was. For a roll of 250Φ single tube, ((0.178×0.178×π)=0.0406m 2 It was.

[0056] (2) The flow rate was measured using a flow meter (clamp-on type flow sensor: manufactured by Keyence Corporation). The flow velocity at each flow rate was calculated from the measured flow rate and the calculated cross-sectional area of ​​the flow passage in the roll. The flow rate when 20° C. water was passed through the roll at each flow rate was calculated using the following formula. Flow velocity (m / s) = Flow rate (L / min) / 60 / 1000 / Cross-sectional area of ​​flow passage in roll (m 2 )" Flow velocity when using a 200Φ double tube roll: Flow velocity at 25 L / min (m / s) = 25 / 60 / 1000 / 0.007213 = 0.0578 Flow velocity at 35 L / min (m / s) = 35 / 60 / 1000 / 0.007213 = 0.0809 Flow velocity at 60 L / min (m / s) = 60 / 60 / 1000 / 0.007213 = 0.139 Flow velocity at 87 L / min (m / s) = 87 / 60 / 1000 / 0.007213 = 0.201 Flow velocity when using a 250Φ single tube roll: Flow velocity at 25 L / min (m / s) = 25 / 60 / 1000 / 0.04062 = 0.0103 Flow velocity at 55 L / min (m / s) = 55 / 60 / 1000 / 0.04062 = 0.0226

[0057] 2. Air layer height at each flow velocity (1) The height of the air layer inside the roll is calculated from the flow rate. Since the roll used above is not transparent, a transparent acrylic roll that allows the water inside the roll to be seen was used, and the height of the air layer was measured with a ruler, and the results were scaled up to convert to a 200Φ double pipe and a 250Φ single pipe. Two types of transparent acrylic rolls were used: a 150φ acrylic double-tube roll with a roll diameter of 150 mm and a length of 300 mm (Figures 2A and 2B) and a 150φ acrylic single-tube roll with a roll diameter of 150 mm and a length of 300 mm (Figures 3A and 3B), and the height of the air layer at each flow rate was measured. FIG. 2A is a cross-sectional view along the axis of a 150φ acrylic double-tube roll, and FIG. 2B is a cross-sectional view taken along the line AA in FIG. 2A. As shown in FIGS. 2A and 2B, the double-tube roll 50 is composed of an outer tube 51 and an inner tube 52. The double-tube roll 50 has a heat medium flow path 55 through which a heat medium flows. The heat medium flow path 55 has an annular first flow path 55a located between the outer tube 51 and the inner tube 52 when viewed from the axial direction of the roll 50, a plurality of second flow paths 55b extending radially from the axis of the roll 50 at one end side of the axial direction of the roll 50 and communicating with one end side of the first flow path 55a, and a plurality of third flow paths 55c extending radially from the axis of the roll 50 at the other end side of the axial direction of the roll 50 and communicating with the other end side of the first flow path 55a. As indicated by the dotted arrows in FIG. 2A, the heat medium flows from the inlet of the roll 50, passes through the second flow path 55b, the first flow path 55a, and the third flow path 55c in this order, and is discharged from the outlet of the roll 50. Fig. 3A is a cross-sectional view taken along the axis of a 150φ acrylic single tube roll, and Fig. 3B is a cross-sectional view taken along line AA in Fig. 3A. As shown in Figs. 3A and 3B, a single tube roll 60 is composed of an outer tube 61. The single tube roll 60 has a heat medium flow path 65 through which a heat medium flows. In other words, the heat medium flow path 65 is composed of the internal space of the outer tube 61. As shown by the dotted arrow in Fig. 3A, the heat medium flows from the inlet of the roll 60, passes through the heat medium flow path 65, and is discharged from the outlet of the roll 60.

[0058] (2) The height of the air layer at each flow speed was measured using the transparent rolls 50 and 60, and the results are shown in the graph of Fig. 4. In Fig. 4, the circles indicate the measured values ​​for the 150φ acrylic double-tube roll, the triangles indicate the measured values ​​for the 150φ acrylic single-tube roll, the horizontal axis indicates the heat transfer medium flow speed (m / s), and the vertical axis indicates the air layer height (mm). As can be seen from Figure 4, the height of the air layer at the same flow rate was almost the same for the 150φ acrylic double-tube roll and the 150φ acrylic single-tube roll. This means that if the same heat transfer medium is flowed through rolls of the same diameter and at the same flow rate, the height of the air layer will be constant regardless of the structure inside the roll.

[0059] (3) The measurements of the transparent roll mentioned above were scaled up, and the height of the air layer at each flow rate was calculated for a 200Φ double-tube roll and a 250Φ single-tube roll. Specifically, the scale-up conversion of the air layer height will be explained using Figure 5. As shown in Figure 5, the air layer height of the 150Φ acrylic double-tube roll is h (mm), and the air layer height of the 200Φ double-tube roll is h' (mm). Then, it can be expressed as h' = h × (178 / 128). And the air layer height when using the 200Φ double-tube roll was calculated as follows. Air layer height (mm) at 25 L / min (flow rate 0.058 m / s) = 6.4 mm × (178 / 128) = 8.9 mm Air layer height (mm) at 35 L / min (flow rate 0.081 m / s) = 2.6 mm × (178 / 128) = 3.6 mm At 60 L / min and 87 L / min, the flow velocity exceeds 0.1 m / s as calculated in 1.(2) above, resulting in an intermittent flow and the air layer height being 0 mm. Similarly, the height of the air layer when a 250Φ single tube roll was used was calculated as follows. Air layer height (mm) at 25 L / min (flow rate 0.010 m / s) = 49 mm × (228 / 128) = 87.3 mm Air layer height (mm) at 55 L / min (flow rate 0.023 m / s) = 34 mm × (228 / 128) = 60.6 mm

[0060] 3. Amount of heat transfer medium (water amount) and heat capacity in the roll (1) Based on the above air layer height, the amount of heat transfer medium in the roll at each flow rate was calculated. In this case, the cross-sectional area of ​​the air layer is calculated using the following formula for the area of ​​a circular arc: S = θ / 2 × r2-(rh)√h(2r-h) [S: cross-sectional area of ​​the air layer, r: roll radius, h: air layer height, θ: θ = 2 acos (1-h / r)] The amount of heat transfer medium in the double tube roll is It was calculated by [(cross-sectional area of ​​outer tube)-(cross-sectional area of ​​inner tube)-(cross-sectional area of ​​air layer)]×(roll length). The amount of heat transfer medium in the single tube roll is It was calculated by [(cross-sectional area of ​​roll)-(cross-sectional area of ​​air layer)]×(length of roll). Amount of heat transfer medium in roll when using 200Φ double tube roll: Amount of heat transfer medium in the roll at 25 L / min (L) = 9.6 (L) Amount of heat transfer medium in the roll at 35 L / min (L) = 10.1 (L) Amount of heat transfer medium in the roll at 60 L / min and 87 L / min (L) = 11.0 (L) (full water condition) Amount of heat transfer medium in roll when using 250Φ single tube roll: Amount of heat transfer medium in the roll at 25 L / min (L) = 32 (L) Amount of heat transfer medium in the roll at 55 L / min (L) = 38 (L)

[0061] (2) The heat capacity was calculated based on the amount of heat transfer medium in the roll. The heat transfer medium was water, and the specific heat of water was 4.18 (kJ / K L). Heat capacity when using a 200Φ double tube roll: Heat capacity at 25 L / min (kJ / K) = 9.6 (L) × 4.18 = 40 (kJ / K) Heat capacity at 35 L / min (kJ / K) = 10.1 (L) × 4.18 = 42 (kJ / K) Heat capacity at 60 L / min (kJ / K) = 11 (L) × 4.18 = 46 (kJ / K) Heat capacity at 87 L / min (kJ / K) = 11 (L) × 4.18 = 46 (kJ / K) Heat capacity when using a 250Φ single tube roll: Heat capacity at 25 L / min (kJ / K) = 32 (L) × 4.18 = 134 (kJ / K) Heat capacity at 55 L / min (kJ / K) = 38 (L) × 4.18 = 159 (kJ / K)

[0062] 4. Measurement of temperature distribution on the roll surface when irradiated with UV light (1) A roll with a surface temperature adjusted to 20°C is irradiated with a UV lamp (I-Graphics Co., Ltd., high pressure mercury) as an activation treatment device with a UVB light intensity of 506 mJ / cm 2 , illuminance 792mW / cm 2 After the temperature stabilized, the temperature was measured at a predetermined position in the width direction of the roll surface. The roll surface temperature was measured using ST-100 (Rika Kogyo Co., Ltd.). Specifically, the temperature was measured at positions a to e in the width direction on the surface of roll 70, as shown in Fig. 6. Position a is 220 mm away from the drive side of roll 70, position b is 545 mm away from the drive side of roll 70, position c is 675 mm away from the drive side of roll 70, position d is 805 mm away from the drive side of roll 70, and position e is 1130 mm away from the drive side of roll 70. The results are shown in Figures 7 and 8. Figure 7 shows the temperature at positions a to e in the width direction of the roll when a 200Φ double-tube roll was used. In Figure 7, the circle marks indicate the measured values ​​at 25 L / min, the triangle marks indicate the measured values ​​at 35 L / min, the square marks indicate the measured values ​​at 60 L / min, and the diamond marks indicate the measured values ​​at 87 L / min. Figure 8 shows the temperature at positions a to e in the width direction of the roll when a 250Φ single-tube roll was used. In Figure 8, the circle marks indicate the measured values ​​at 25 L / min, and the triangle marks indicate the measured values ​​at 55 L / min.

[0063] (2) The maximum temperature difference in the width direction of the roll surface was obtained from the results of Figures 7 and 8. In other words, the maximum temperature difference on the roll surface is the value obtained by subtracting the minimum temperature on the roll surface in the width direction from the maximum temperature on the roll surface in the width direction. Here, the unit of the maximum temperature difference is shown in °C, but there is no problem if it is replaced with K. The same applies to the following explanation. When a 200Φ double-tube roll was used, the maximum temperature differences between each measurement point were as follows: Temperature difference at 25 L / min (℃) : 5.7 (℃) Temperature difference at 35 L / min (℃) : 5.0 (℃) Temperature difference at 60 L / min (℃) : 3.1 (℃) Temperature difference at 87 L / min (℃) : 2.0 (℃) When a 250Φ single tube roll was used, the maximum temperature difference between each measurement point was as follows. Temperature difference at 25 L / min (℃) : 1.7 (℃) Temperature difference at 55 L / min (℃) : 1.0 (℃)

[0064] 5. Heat quantity of the heat medium in the roll, heat capacity of the heat medium in the roll, and amount of the heat medium in the roll (1) Using the heat capacity (kJ / K) calculated based on the amount of heat transfer medium in the roll and the measured maximum roll temperature difference (℃), the amount of heat (kJ) applied to the heat transfer medium in the roll due to the maximum roll temperature difference was calculated from the following formula. Heat quantity (kJ) = Heat capacity based on the amount of heat transfer medium in the roll (kJ / K) × Maximum roll temperature difference (℃) Here, for a 200Φ double tube roll and a 250Φ single tube roll, if the flow rate is 25 L / min, 200Φ double tube roll: 40 (kJ / K) × 5.7 (℃) = 228 (kJ) 250Φ single tube roll: 134 (kJ / K) × 1.7 (℃) = 228 (kJ) It was found that at a flow rate of 25 L / min, the amount of heat applied to the heat transfer medium inside the roll was constant at 228 kJ, regardless of the roll shape.

[0065] (2) From the heat amount of the heat medium inside the roll resulting from this maximum roll temperature difference, the heat capacity (kJ / K) of the heat medium inside the roll and the amount of heat medium (amount of water) (L) inside the roll were calculated so that the maximum roll temperature differences would be 3.0°C, 2.0°C, and 1.0°C. For a maximum temperature difference of 3.0°C: Heat capacity (kJ / K) = 228 (kJ) / 3.0 (°C) = 76 (kJ / K) Amount of heat medium in roll (L) = 76 (kJ / K) / 4.18 (kJ / K L) =18.2 (L) For a maximum temperature difference of 2.0°C: Heat capacity (kJ / K) = 228 (kJ) / 2.0 (°C) = 114 (kJ / K) Amount of heat medium in roll (L) = 114 (kJ / K) / 4.18 (kJ / K L) =27.3 (L) For a maximum temperature difference of 1.0°C: Heat capacity (kJ / K) = 228 (kJ) / 1.0 (°C) = 228 (kJ / K) Amount of heat medium in roll (L) = 228 (kJ / K) / 4.18 (kJ / K L) =54.5 (L)

[0066] (3) From the results of 3.(1) and 5.(1)(2) above, when the flow rate is 25 L / min, the relationship between the amount of heat X1 (kJ) of the heat transfer medium in the roll resulting from the maximum roll temperature difference, the heat capacity X2 (kJ / K) of the heat transfer medium in the roll, the amount of heat transfer medium in the roll (L), and the maximum roll temperature difference (℃) is shown in Table 2 below.

[0067] [Table 2]

[0068] As shown in Table 2, number 1 indicates the actual measured value of a 200Φ double-tube roll, and number 2 indicates the actual measured value of a 250Φ single-tube roll. Numbers 3, 4, and 5 indicate calculated values. Note that in Table 2, when a 200Φ double-tube roll is used, the maximum capacity of the heat transfer medium in the roll is 11.0 (L), so numbers 2 to 5 are not applicable.

[0069] (4) Using the same method as for the flow rate of 25 L / min, the amount of heat applied to the heat medium in the roll caused by the maximum roll temperature difference when the flow rate is 60 L / min is calculated as follows: 200Φ double tube roll: 46 (kJ / K) × 3.1 (℃) = 143(kJ) It was. From this heat quantity, the heat capacity (kJ / K) of the heat medium in the roll and the amount of heat medium in the roll (L) were calculated so that the maximum roll temperature differences would be 3.0°C, 2.0°C, and 1.0°C. For a maximum temperature difference of 3.0°C: Heat capacity (kJ / K) = 143 (kJ) / 3.0 (°C) = 48 (kJ / K) Amount of heat medium in roll (L) = 48 (kJ / K) / 4.18 (kJ / K L) =11.5 (L) For a maximum temperature difference of 2.0°C: Heat capacity (kJ / K) = 143 (kJ) / 2.0 (°C) = 73 (kJ / K) Amount of heat medium in roll (L) = 73 (kJ / K) / 4.18 (kJ / K L) =17.5 (L) For a maximum temperature difference of 1.0°C: Heat capacity (kJ / K) = 143 (kJ) / 1.0 (°C) = 143 (kJ / K) Amount of heat medium in roll (L) = 143 (kJ / K) / 4.18 (kJ / K L) =34.2 (L) From these results, when the flow rate is 60 L / min, the relationship between the amount of heat X1 (kJ) of the heat transfer medium in the roll resulting from the maximum roll temperature difference, the heat capacity X2 (kJ / K) of the heat transfer medium in the roll, the amount of heat transfer medium in the roll (L), and the maximum roll temperature difference (℃) is shown in Table 3 below.

[0070] [Table 3]

[0071] As shown in Table 3, number 1 indicates the actual measured value of the 200Φ double-tube roll, and numbers 2, 3, and 4 indicate the calculated values. Note that in Table 3, when a 200Φ double-tube roll is used, the maximum capacity of the heat transfer medium in the roll (volume of the roll) is 11.0 (L), so numbers 2 to 4 are not applicable.

[0072] 6. Regarding the above formula (1) and formula (2) (1) As can be seen from Tables 2 and 3, (X1 / X2) in formula (1) indicates the maximum roll temperature difference. In other words, formula (1) indicates that the maximum roll temperature difference is greater than 0 K and equal to or less than 3.5 K. In addition, (X2 / Sc) in formula (2) indicates the amount of heat transfer medium in the roll. Sc is the specific heat of the heat transfer medium (in Tables 2 and 3, the specific heat of water is 4.18 (kJ / K L)). The lower limit of formula (2) (X1 / (3.5×Sc)) is the amount of heat transfer medium in the roll required when the maximum roll temperature difference is 3.5K. In other words, formula (2) indicates that the amount of heat transfer medium in the roll is equal to or greater than the amount of heat transfer medium required when the maximum roll temperature difference is 3.5K, and equal to or less than the roll volume.

[0073] (2) Next, it will be explained that when formula (1) is satisfied, the reaction rate of the adhesive can be made approximately uniform in the width direction of the roll. Table 4 shows the roll minimum temperature Tmin, roll maximum temperature Tmax, roll maximum temperature difference ΔT (Tmax-Tmin), reaction rate constant kmin of the roll minimum temperature, reaction rate constant kmax of the roll maximum temperature, and reaction rate ratio kmax / kmin of the roll maximum temperature and the roll minimum temperature. The reaction rate constant k was calculated from the Arrhenius equation: k = A exp(-Ea / RT). (A: constant, Ea: activation energy, R: gas constant, T: absolute temperature (K)) The activation energy Ea was set to 59,400 (J / mol) based on the activation energy value of epoxy resins listed in the Polymer Handbook.

[0074] [Table 4]

[0075] As shown in Table 4, number 1 indicates the actual measured value of a 200Φ double-walled roll at a flow rate of 25 L / min, number 2 indicates the actual measured value of a 250Φ single-wall roll at a flow rate of 25 L / min, and numbers 3, 4, and 5 indicate the calculated values ​​when Tmin is fixed at 25°C.

[0076] As can be seen from Table 4, the larger the maximum roll temperature difference ΔT, the larger the reaction rate ratio. In other words, due to temperature unevenness in the width direction of the roll surface, differences in the reaction rate of the adhesive occur in the width direction of the roll. This difference in the reaction rate of the adhesive affects the quality of the laminated film. When the maximum roll temperature difference is greater than 0 K and equal to or less than 3.5 K, that is, when formula (1) is satisfied, the reaction rate ratio is greater than 1 and smaller than 1.32, so that the difference in reaction rate can be reduced and problems with the quality of the laminated film can be reduced. Preferably, the maximum temperature difference between the rolls is 3 K or less, more preferably 2 K or less, so that the reaction rate ratio can be made smaller and problems with the quality of the laminated film can be reduced.

[0077] (3) Furthermore, when formula (2) is satisfied, that is, the amount of heat transfer medium that causes the maximum roll temperature difference to be 3.5 K or less is flowed through the roll, so that the maximum roll temperature difference can be made 3.5 K or less. Therefore, the temperature unevenness in the width direction of the roll surface is reduced, the reaction speed of the adhesive in the width direction of the laminated film is made substantially uniform, and problems with the quality of the laminated film can be reduced.

[0078] (Second Manufacturing Example of Optical Laminate) (1) Manufacturing of λ / 2 retardation layer The above-mentioned composition for alignment layer was applied to a triacetyl cellulose film having a thickness of 80 μm and a width of 1340 mm, and then dried to perform λ / 2 alignment treatment. Next, a coating solution containing a discotic liquid crystal compound was applied to the alignment surface, and the alignment of the liquid crystal compound was fixed by heating and UV irradiation, thereby forming a λ / 2 liquid crystal layer having a thickness of 2 μm on the alignment surface.

[0079] (2) Manufacturing of λ / 4 retardation layer The above-mentioned composition for the alignment layer was applied to a triacetyl cellulose film having a thickness of 80 μm and a width of 1,340 mm, and then dried to obtain a transparent resin substrate for λ / 4 alignment. A coating liquid containing a rod-shaped polymerizable nematic liquid crystal monomer was then applied to the obtained transparent resin substrate for λ / 4 alignment, and solidified while maintaining the refractive index anisotropy, thereby obtaining a λ / 4 liquid crystal layer having a thickness of 1 μm on the transparent resin substrate for λ / 4 alignment.

[0080] (3) Manufacturing of optical laminates A corona discharge treatment was performed at an output intensity of 800 W on each of the liquid crystal layer sides of the λ / 2 retardation layer and the λ / 4 retardation layer. Furthermore, using a manufacturing apparatus as shown in FIG. 1, the obtained λ / 2 retardation layer and the obtained λ / 4 retardation layer were laminated together via the coating layer forming composition (cationically polymerizable, viscosity 40 mPa s) used in the first manufacturing example. Specifically, the lamination apparatus was arranged so that the angle between the slow axis of the λ / 2 retardation layer (corresponding to reference number 31 in FIG. 1) and the slow axis of the λ / 4 retardation layer (corresponding to reference number 32 in FIG. 1) was 60°, and while conveying each retardation layer, the composition for forming the coating layer was applied to the λ / 2 liquid crystal layer side of the λ / 2 retardation layer to a thickness of 3 μm, and further, the λ / 4 liquid crystal layer and the λ / 2 liquid crystal layer were laminated with a lamination roll (corresponding to reference numbers 21 and 22 in FIG. 1). The laminate obtained by the lamination was conveyed, and an ultraviolet irradiation device (manufactured by Fusion UV Systems Co., Ltd.) was used to irradiate the laminate from the λ / 4 retardation layer side on a double tube roll set under the conditions described below, with an accumulated light amount of 400 mJ / cm. 2 The adhesive was cured by irradiating it with ultraviolet light (UV-B), thereby obtaining an optical laminate having a laminate structure consisting of λ / 2 retardation layer / adhesive layer / λ / 4 retardation layer.

[0081] In the second manufacturing example, the following double tube roll was used: (1) A double-tube roll (corresponding to reference symbol 12 in FIG. 1) was used, which was made of rolled steel (SM490A), had an outer tube (thickness: 12 mm) and an inner tube (thickness: 7.5 mm), and had a structure in which the hot solvent flowed between the outer tube and the inner tube. The roll had an outer diameter of 200 mm and a length of 1,350 mm. (2) As the hot solvent, water adjusted to 25°C (condition 2), 50°C (conditions 5 to 7), or 75°C (conditions 3 and 4) was used, and the temperature of the roll surface was adjusted by circulating the hot solvent inside the double-tube roll during ultraviolet irradiation. (3) The flow rate of the hot solvent was measured using a flowmeter (clamp-on type flow sensor: manufactured by Keyence), and the temperature was measured using ST-100 (Rika Kogyo Co., Ltd.) at predetermined positions in the width direction of the adjusted roll surface (positions a to e shown in FIG. 6). Position a is a position 220 mm away from the drive side of roll 70, position b is a position 545 mm away from the drive side of roll 70, position c is a position 675 mm away from the drive side of roll 70, position d is a position 805 mm away from the drive side of roll 70, and position e is a position 1130 mm away from the drive side of roll 70. The maximum temperature difference between each measurement point was as follows: Flow rate was 25 L / min. Condition 2 Temperature difference with temperature control (water temperature 25℃) (℃): 32.7-27.0=5.7(℃) Condition 3: Temperature difference with temperature control (water temperature 75°C): 82.7-77.0=5.7(°C) Condition 4: Temperature difference with temperature control (water temperature 75°C): 80.5-77.0=3.5(°C) Condition 5: Temperature difference with temperature control (water temperature 50℃) (℃): 55.5-52.0=3.5(℃) Condition 6 Temperature difference with temperature control (water temperature 50℃) (℃): 53.7-52=1.7(℃) Condition 7 Temperature difference with temperature control (water temperature 50℃) (℃): 53.0-52.0=1.0(℃) (4) The heat quantity (KJ) of the heat transfer medium in the roll resulting from the maximum temperature difference in the width direction of the roll surface and the heat capacity (KJ / K) of the heat transfer medium in the roll are shown in Table 5. The heat capacity values ​​were calculated using the same procedure as for the data shown in Table 3. As a comparative manufacturing example, an optical laminate was manufactured using the manufacturing apparatus shown in FIG. 1 without the roll 12, under the same procedures and conditions as those of the second manufacturing example (hereinafter also referred to as "Condition 1").

[0082] (Evaluation of the optical laminate obtained in the second production example) A test piece measuring 1340 mm wide x 300 mm long was cut out from the obtained optical laminate. The obtained test pieces were irradiated with light having an illuminance of 2600 lx, and the presence or absence of film defects (white spots) was visually observed. Here, "present" of film defects refers to a state in which a large number of fine white spots were observed, and "absent" of film defects refers to a state in which no white spots were observed. The results of film defects under the above conditions 1 to 7 are shown in Table 5 below. In Table 5, conditions 1 to 7 are indicated with numbers 1 to 7. In Table 5, the roll 12 shown in FIG. 1 is used as the temperature control roll.

[0083] [Table 5] [Explanation of symbols]

[0084] 1. Optical laminate manufacturing equipment 5 Laminating device 6. Control device 11 Adhesive coating device 12 rolls 13 Activation treatment equipment 20 Winding roll 21 First laminating roll 22 Second laminating roll 31 First film (polarizing film) 32 2nd film (transparent film) 33 Laminating film 34 Optical laminate (polarizing plate) 50 Double tube roll 51 Outer tube 52 Inner tube 55 Heat transfer medium flow path 55a First flow path 55b Second flow path 55c Third flow path 60 Single tube roll 61 Outer tube 65 Heat transfer medium flow path 70 rolls

Claims

1. A method for producing an optical laminate having at least one layer made of an optical film, comprising: a bonding step of bonding two different films together via an energy ray activated adhesive to form a bonded film; an activation treatment step of irradiating the adhesive film with an energy ray on the roll while bringing the adhesive film into contact with the roll, thereby activating the adhesive; A heating step of heating the adhesive film having undergone the activation treatment, The roll is a double-tube roll composed of an outer tube and an inner tube, The roll has a heat medium flow path therein through which a heat medium flows, the heat medium flow path has an annular first flow path located between the outer tube and the inner tube when viewed in the axial direction of the roll, a plurality of second flow paths extending radially from the axis of the roll at one end side of the axial direction of the roll and communicating with one end side of the first flow path, and a plurality of third flow paths extending radially from the axis of the roll at the other end side of the axial direction of the roll and communicating with the other end side of the first flow path, the heating step is carried out by adjusting the temperature of the surface of the roll to within a range of 30°C to 90°C by the heat medium flowing through the heat medium flow path, and The activation treatment step is performed by passing a heat medium through the heat medium flow path while rotating the roll. Formula (1): 0<X1 / X2≦3.5 (X1: Heat quantity of the heat medium in the roll caused by the maximum temperature difference in the width direction of the roll surface (KJ), X2: Heat capacity of the heat medium in the roll (KJ / K)) The method for producing an optical laminate is carried out while maintaining the above range.

2. The activation treatment step further comprises: Formula (2): X1 / (3.5×Sc)≦X2 / Sc≦V (Sc: specific heat of heat transfer medium (KJ / K・L), V: maximum capacity of heat transfer medium in roll (L)) The method for producing an optical laminate according to claim 1 , comprising flowing a heat medium within a range that satisfies the above.

3. The method for producing an optical laminate according to claim 1 or 2, wherein the activation treatment step further comprises adjusting the temperature distribution in the width direction of the surface of the roll to 3° C. or less.

4. The method for producing an optical laminate according to claim 1 , wherein the activation treatment step further includes discharging air within the roll from a downstream side of a heat transfer medium flow path to outside the roll.

5. An apparatus for producing an optical laminate having at least one layer made of an optical film, comprising: a lamination device that laminates two different films together via an energy ray activated adhesive to form a laminated film; A roll that comes into contact with the laminated film, the roll being a double-tube roll composed of an outer tube and an inner tube, and having a heat medium flow passage therein through which a heat medium flows, the heat medium flow passage having an annular first flow passage located between the outer tube and the inner tube when viewed from the axial direction of the roll, a plurality of second flow passages extending radially from the axis of the roll at one end side of the axial direction of the roll and communicating with one end side of the first flow passage, and a plurality of third flow passages extending radially from the axis of the roll at the other end side of the axial direction of the roll and communicating with the other end side of the first flow passage; an activation treatment device that irradiates the adhesive film on the roll with energy rays to perform an activation treatment of the adhesive; When the activation treatment of the adhesive is performed by the activation treatment device, the surface temperature of the roll is adjusted to within a range of 30° C. to 90° C., and the roll is Formula (1): 0<X1 / X2≦3.5 (X1: Heat quantity of the heat medium in the roll caused by the maximum temperature difference in the width direction of the roll surface (KJ), X2: Heat capacity of the heat medium in the roll (KJ / K)) A control device that controls the control so as to maintain the range satisfying An apparatus for manufacturing an optical laminate comprising:

6. The control device, when performing the activation process of the adhesive by the activation process device, further Formula (2): X1 / (3.5×Sc)≦X2 / Sc≦V (Sc: specific heat of heat transfer medium (KJ / K・L), V: maximum capacity of heat transfer medium in roll (L)) The apparatus for producing an optical laminate according to claim 5 , wherein the heat medium is controlled to flow within a range that satisfies the above.

7. The optical laminate manufacturing apparatus according to claim 5 or 6, wherein the control device further controls the temperature distribution in the width direction of the surface of the roll to be 3.5°C or less when the activation treatment of the adhesive is performed by the activation treatment device.

8. The apparatus for manufacturing an optical laminate according to any one of claims 5 to 7, wherein the roll further has an air vent passage downstream of the heat transfer medium passage, the air vent passage being connected to the heat transfer medium passage and configured to discharge air within the heat transfer medium passage to the outside of the roll.

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