Method for producing optical laminate and apparatus for producing optical laminate

Abstract

The present invention provides a method and apparatus for producing an optical laminate that can reduce temperature unevenness across the width of a roller surface, thereby reducing quality issues with a laminated film. The method includes a specific lamination step and a specific activation step.

Description

Technical Field

[0001] The present invention relates to a method for producing an optical layered body and an apparatus for producing an optical layered body. Background Art

[0002] In the manufacture of optical laminates such as polarizing plates, after the optical films constituting the various layers of the optical laminate are bonded together using an energy-ray-activated adhesive, the resulting bonded film is then activated while being transported. This activation treatment is performed by irradiating the bonded film with energy rays while it passes over a roller. To prevent quality issues such as deformation and uneven curing of the bonded film, the energy ray irradiation is typically performed while the bonded film is cooled on a cooled roller.

[0003] Conventionally, as a method for cooling a roller, for example, a method of circulating a heat medium inside the roller is known, as disclosed in Japanese Patent Application Laid-Open No. 2019-3210 (Patent Document 1).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2019-3210 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] However, when a heat medium is circulated through the roller as in the conventional method, temperature nonuniformity may occur across the width of the roller surface. Furthermore, this temperature nonuniformity across the width of the roller surface can cause uneven reaction rates of the adhesive across the width of the laminated film, potentially causing quality issues with the laminated film.

[0009] Therefore, the present disclosure provides a method for producing an optical layered body and an apparatus for producing an optical layered body that reduce temperature unevenness in the width direction of the surface of a roll and thereby reduce problems in the quality of a bonding film.

[0010] Means used to solve problems

[0011] In order to solve the above-mentioned problems, a method for producing an optical layered body as one embodiment of the present disclosure is a method for producing an optical layered body having at least one layer including an optical film.

[0012] The manufacturing method comprises:

[0013] a laminating step of laminating two different films via an energy ray-activated adhesive to form a laminated film; and

[0014] an activation treatment step of irradiating the laminating film with energy rays on the roller while bringing the laminating film into contact with the roller to activate the adhesive;

[0015] The roller has a heat medium flow path inside which the heat medium flows.

[0016] The activation treatment step is performed while the heat medium flows through the heat medium flow path and the roller is maintained in a state satisfying the range of formula (1).

[0017] Formula (1): 0<X1 / X2≤3.5

[0018] (X1: Heat amount of the heat medium in the roller caused by the maximum temperature difference in the width direction of the roller surface (KJ), X2: Heat capacity of the heat medium in the roller (KJ / K))

[0019] Here, in this specification, X1 is a value obtained by subtracting the amount of heat applied to the heat medium in the roller at the minimum temperature in the width direction of the roller surface from the amount of heat applied to the heat medium in the roller at the maximum temperature in the width direction of the roller surface.

[0020] According to the method, since the activation treatment process is carried out while maintaining the roller in the range of formula (1): 0<X1 / X2≤3.5, the temperature unevenness in the width direction of the surface of the roller can be reduced, and the reaction rate of the adhesive in the width direction of the bonding film can be made roughly uniform, thereby reducing the quality problems of the bonding film.

[0021] In one embodiment of the method for producing an optical layered body, the activation treatment step preferably further includes an operation of circulating a heat medium within a range satisfying formula (2).

[0022] Formula (2): X1 / (3.5×Sc)≤X2 / Sc≤V

[0023] (Sc: specific heat of the heat medium (kJ / K·L), V: maximum capacity of the heat medium in the roller (L))

[0024] According to the embodiment, since the activation treatment process includes the operation of circulating a heat medium within the range satisfying formula (2): X1 / (3.5×Sc)≤X2 / Sc≤V, a sufficient amount of heat medium can be circulated, which can further reduce the temperature unevenness in the width direction of the surface of the roller, thereby further reducing the quality problem of the laminated film.

[0025] In one embodiment of the method for producing an optical layered body, the activation treatment step preferably further includes an operation of adjusting the temperature distribution of the surface of the roller in the width direction to 3° C. or less.

[0026] According to the embodiment, since the activation treatment step includes an operation of making the temperature distribution of the roller surface in the width direction 3°C or less, the temperature unevenness in the width direction of the roller surface can be further reduced, thereby further reducing the quality problems of the laminated film.

[0027] In one embodiment of the method for producing an optical layered body, the activation treatment step preferably further includes an operation of discharging air in the roller to the outside of the roller from a downstream side of a heat medium flow path.

[0028] According to this embodiment, since the activation process includes exhausting the air in the roller from the downstream side of the heat medium flow path, the temperature unevenness in the width direction of the roller surface can be further reduced, thereby further reducing the quality problems of the laminated film.

[0029] Furthermore, an apparatus for producing an optical layered body according to one embodiment of the present disclosure is an apparatus for producing an optical layered body having at least one layer including an optical film, and the apparatus includes:

[0030] a laminating device for laminating two different films via an energy ray-activated adhesive to form a laminated film;

[0031] a roller in contact with the laminating film and having a heat medium flow path therein for circulating a heat medium;

[0032] an activation treatment device for irradiating the laminating film with energy rays on the roller to perform activation treatment on the adhesive; and

[0033] The control device controls the roller so as to maintain the roller within a range satisfying the formula (1) when the activation treatment device performs the activation treatment on the adhesive.

[0034] Formula (1): 0<X1 / X2≤3.5

[0035] (X1: Heat amount of the heat medium in the roller caused by the maximum temperature difference in the width direction of the roller surface (KJ), X2: Heat capacity of the heat medium in the roller (KJ / K))

[0036] According to the method, since the control device controls the roller in a manner that maintains it within the range that satisfies the formula (1): 0<X1 / X2≤3.5, the temperature unevenness in the width direction of the surface of the roller can be reduced, the reaction rate of the adhesive in the width direction of the bonding film can be made roughly uniform, and the quality problems of the bonding film can be reduced.

[0037] In one embodiment of the optical laminate manufacturing apparatus, it is preferred that when the activation treatment device performs the activation treatment of the adhesive, the control device further controls so that the heat medium flows within a range satisfying formula (2).

[0038] Formula (2): X1 / (3.5×Sc)≤X2 / Sc≤V

[0039] (Sc: specific heat of the heat medium (kJ / K·L), V: maximum capacity of the heat medium in the roller (L))

[0040] According to the embodiment, since the control device controls the heat medium in a manner that circulates within the range that satisfies formula (2): X1 / (3.5×Sc)≤X2 / Sc≤V, a sufficient amount of heat medium can be circulated, which can further reduce the temperature unevenness in the width direction of the surface of the roller, thereby further reducing the quality problem of the bonding film.

[0041] In one embodiment of the optical laminate manufacturing apparatus, it is preferred that the control device further controls the roller surface so that the temperature distribution in the width direction is 3.5° C. or less when the activation treatment device activates the adhesive.

[0042] According to the embodiment, since the control device also makes the temperature distribution of the width direction of the roller surface below 3°C when the activation treatment device is used to activate the adhesive, the temperature unevenness of the width direction of the roller surface can be further reduced, thereby further reducing the quality problems of the bonding film.

[0043] In one embodiment of the optical laminate production apparatus, the roller preferably further includes an exhaust air flow path on the downstream side of the heat medium flow path, communicating with the heat medium flow path and exhausting air in the heat medium flow path to the outside of the roller.

[0044] According to this embodiment, since the roller has an exhaust air flow path connected to the heat medium flow path, the heat medium can be circulated within the roller while the air inside the roller is exhausted. This reduces temperature unevenness across the width of the roller surface, making the adhesive reaction rate substantially uniform across the width of the laminating film, thereby reducing quality issues with the laminating film.

[0045] Effects of the Invention

[0046] According to the manufacturing method and the manufacturing apparatus of the optical layered body which are one embodiment of the present disclosure, the temperature unevenness in the width direction of the surface of the roller can be reduced, and thus the problem of the quality of the bonding film can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a schematic diagram which shows the 1st embodiment of the manufacturing apparatus of the optical layered body.

[0048] Figure 2A This is a cross-sectional view taken along the axis of a 150φ acrylic double-tube roller.

[0049] Figure 2B yes Figure 2A AA cross-sectional view.

[0050] Figure 3A This is a cross-sectional view along the axis of a 150φ acrylic single tube roller.

[0051] Figure 3B yes Figure 3A AA cross-sectional view.

[0052] Figure 4 It is a graph showing the relationship between the flow velocity (m / s) of the heat medium and the height (mm) of the air layer.

[0053] Figure 5 This is an enlarged view showing an acrylic double-tube roller performed in Examples.

[0054] Figure 6 It is a top view of the roller showing positions a to e in the width direction of the roller surface.

[0055] Figure 7 This is a graph showing the temperatures at positions a to e in the width direction of the roll when a 200φ double-tube roll is used.

[0056] Figure 8 This is a graph showing the temperatures at positions a to e in the width direction of the roll when a 250φ single-tube roll is used.

[0057] Description of Reference Numerals

[0058] 1. Apparatus for manufacturing an optical laminate, 5. Laminating apparatus, 6. Control apparatus, 11. Adhesive coating apparatus, 12. Roller, 13. Activation treatment apparatus, 20. Winding roller, 21. First laminating roller, 22. Second laminating roller, 31. First film (polarizing film), 32. Second film (transparent film), 33. Laminating film, 34. Optical laminate (polarizing plate), 50. Double tube roller, 51. Outer tube, 52. Inner tube, 55. Heat medium flow path, 55a. First flow path, 55b. Second flow path, 55c. Third flow path, 60. Single tube roller, 61. Outer tube, 65. Heat medium flow path, 70. Roller. DETAILED DESCRIPTION

[0059] Hereinafter, a method for producing an optical layered body and an apparatus for producing an optical layered body, which are one embodiment of the present disclosure, will be described in detail using the illustrated embodiments. Note that the drawings are partially schematic and may not reflect actual dimensions or ratios.

[0060] (First embodiment)

[0061] (Device)

[0062] Figure 1 Schematic diagram showing a first embodiment of an apparatus for producing an optical laminate. Figure 1 As shown, the manufacturing device 1 of the optical layered body includes a bonding device 5 for bonding a first film 31 and a second film 32 that are different from each other to form a bonding film 33, a roller 12 that contacts the bonding film 33, an activation treatment device 13 for irradiating energy rays to the bonding film 33 to form an optical layered body 34, and a control device 6 for controlling the roller 12.

[0063] 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. Figure 1 Transport in the direction of the arrow.

[0064] The optical film is a resin film exhibiting optical characteristics, such as a polarizing film and a retardation film. The polarizing film is formed by, for example, dyeing a uniaxially stretched polyvinyl alcohol film with iodine or a dichroic dye and then treating it with boric acid.

[0065] Examples of the transparent film include thermoplastic resins such as amorphous polyolefin resin films, polyester resin films, acrylic resin films, polycarbonate resin films, polysulfone resin films, and alicyclic polyimide resin films. A resin film with low water vapor permeability is preferred. Examples of the transparent film include cellulose acetate resin films such as triacetylcellulose films and diacetylcellulose films.

[0066] The laminating device 5 includes an adhesive coating device 11 for coating an adhesive on one side of the first film 31, and first and second laminating rollers 21 and 22 for laminating the first and second films 31 and 32 together via the adhesive. The adhesive is an energy ray activated adhesive.

[0067] From the perspectives of weather resistance, refractive index, and cationic polymerizability, an adhesive such as an epoxy resin containing no aromatic rings in the molecule is used. Examples of epoxy resins include hydrogenated epoxy resins, alicyclic epoxy resins, and aliphatic epoxy resins. A polymerization initiator, such as a photocationic polymerization initiator for polymerization by irradiation with active energy rays or a thermal cationic polymerization initiator for polymerization by heating, and other additives (such as sensitizers) are added to the epoxy resin.

[0068] The roller 12 is driven to rotate around the axis of the roller 12, and the laminating film 33 is transported while being in contact with the surface of the roller 12. That is, when the laminating film 33 is irradiated with energy rays from the activation treatment device 13, the temperature unevenness in the width direction of the roller 12 is made roughly uniform. The roller 12 has a heat medium flow path inside which a heat medium flows, and the heat medium flows in the heat medium flow path, thereby cooling the laminating film 33. The heat medium is, for example, water. The roller 12 can be composed of, for example, a double tube of an outer tube and an inner tube. 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 roller 12. Alternatively, the roller 12 can be composed of, for example, a single tube of an outer tube. In this case, the heat medium flow path is formed inside the outer tube.

[0069] The activation device 13 is positioned facing the roller 12. The activation device 13 irradiates the laminating film 33 on the roller 12 with energy rays to activate the adhesive. Specifically, the activation device 13 polymerizes and cures the adhesive by irradiation with energy rays. The optical laminate 34 formed by the activation treatment by the activation device 13 is wound up by the winding roller 20.

[0070] The activation treatment device 13 has a light emission distribution at a wavelength of 400 nm or less, and uses 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, or the like.

[0071] When the activation treatment device 13 performs activation treatment on the adhesive, the control device 6 controls the roller 12 so as to maintain the roller 12 within the range satisfying the formula (1): 0<X1 / X2≤3.5.

[0072] X1 is the heat amount (kJ) of the heat medium within roller 12 resulting from the maximum temperature difference across the width of roller 12. Specifically, X1 is the value obtained by subtracting the heat amount applied to the heat medium within roller 12 at the minimum temperature across the width of roller 12 from the heat amount applied to the heat medium within roller 12 at the maximum temperature across the width of roller 12. X2 is the heat capacity of the heat medium within roller 12 (kJ / K). The calculation method for equation (1) will be described later.

[0073] Specifically, the control device 6 is constituted by a central processing unit. The control device 6 controls the heat medium in the roller 12 by adjusting, for example, the flow rate of the heat medium in the roller 12, the flow rate, the temperature, or the amount of the heat medium in the roller 12 so as to maintain the heat medium within the range satisfying equation (1).

[0074] According to this setting, since the control device 6 controls the roller 12 in a manner to maintain it within the range of formula (1), the temperature unevenness in the width direction of the surface of the roller 12 can be reduced, and the reaction rate of the adhesive in the width direction of the bonding film 33 can be made roughly uniform, thereby reducing the quality problems of the bonding film 33.

[0075] When the activation treatment device 13 is performing the activation treatment of the adhesive, the control device 6 preferably further controls the flow of the heat medium within the range satisfying the following equation (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 of the heat medium in the roller 12 (L). The lower limit value of equation (2) (X1 / (3.5×Sc)) is the capacity of the heat medium required to achieve a maximum temperature difference of 3.5K across the width of the roller 12. The calculation method of equation (2) will be described later.

[0076] According to this configuration, a sufficient amount of heat medium can flow through the roller 12, and the temperature unevenness in the width direction of the surface of the roller 12 can be further reduced, thereby further reducing the quality problem of the laminated film.

[0077] When the activation treatment device 13 is performing the activation treatment of the adhesive, the control device 6 preferably controls the roller 12 so that the temperature distribution (maximum temperature difference) in the width direction of the roller 12 surface is 3.5°C or less, more preferably so that the temperature distribution (maximum temperature difference) in the width direction of the roller 12 surface is 3°C or less, and even more preferably so that the temperature distribution (maximum temperature difference) in the width direction of the roller 12 surface is 2°C or less. In other words, the control device 6 preferably controls the roller 12 so that the difference between the maximum temperature in the width direction of the roller 12 surface and the minimum temperature in the width direction of the roller 12 surface (outer surface) is 3.5°C or less, and more preferably so that the difference is 3°C or less.

[0078] According to this configuration, the temperature unevenness in the width direction of the surface of the roller 12 can be further reduced, and the quality problem of the sticking film 33 can be further reduced.

[0079] Roller 12 preferably also includes an exhaust air passage that communicates with the heat medium passage and discharges air from the heat medium passage to the outside of the roller. This arrangement allows the heat medium to circulate within roller 12 while simultaneously discharging air from the roller. This reduces temperature unevenness across the width of roller 12, making the adhesive's reaction rate roughly uniform across the width of the laminating film 33 and minimizing quality issues with the laminating film 33. It should be noted that the exhaust air passage can discharge not only air but also the heat medium.

[0080] The exhaust air flow path is preferably provided downstream of the heat medium flow path. The roller 12 preferably has a plurality of exhaust air flow paths. When the roller 12 has a plurality of exhaust air flow paths, the exhaust air flow paths are preferably provided at equal intervals around the rotation axis of the roller 12.

[0081] The temperature of the outer surface of the roller 12 can be adjusted by the heat medium flowing through the roller 12. Since the roller 12 having the exhaust air flow path can easily increase the flow rate of the heat medium flowing through the roller 12, it is easy to adjust the temperature of the outer surface uniformly.

[0082] It should be noted that the manufacturing device of the present disclosure is not limited to the above-mentioned embodiment, and the design can be changed within the scope of the main purpose of the present disclosure. For example, the optical film can 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 shows optical properties. The obtained optical laminate can be any one having at least one layer containing an optical film. That is, the optical laminate can be an optical laminate having a film that does not show optical properties, as long as it is an optical laminate that shows optical properties. For example, it can be an optical film such as a phase difference film, a protective film, the above-mentioned polarizing film, or an optical laminate laminated with these films or a thermoplastic resin.

[0083] Furthermore, the manufacturing apparatus may include two or more activation treatment devices and two or more rollers. In the manufacturing apparatus, a plurality of activation treatment devices may be provided facing one roller.

[0084] (Preparation method)

[0085] Next, use Figure 1 One embodiment of a method for producing an optical layered body will be described.

[0086] First, the first film 31 and the second film 32 are bonded together using an energy-ray-activated adhesive to form a bonded film 33. This is referred to as a bonding process. Subsequently, while the bonded film 33 is in contact with the roller 12, energy rays are irradiated onto the bonded film 33 on the roller 12 to activate the adhesive. This is referred to as an activation process. The activation process is performed while a heat medium is flowing through the heat medium flow path and the roller 12 is maintained in a state that satisfies the following equation (1): 0 < X1 / X2 ≤ 3.5.

[0087] Since the activation treatment process is performed while maintaining the roller 12 within the range of formula (1), the temperature unevenness in the width direction of the surface of the roller 12 can be reduced, and the reaction rate of the adhesive in the width direction of the bonding film 33 can be made roughly uniform, thereby reducing the quality problems of the bonding film 33.

[0088] The activation treatment step preferably further includes circulating a heat medium within a range satisfying the following equation (2): X1 / (3.5×Sc)≤X2 / Sc≤V. This configuration allows a sufficient amount of heat medium to flow through the roller 12, further reducing temperature variations across the width of the roller 12 surface, thereby further alleviating quality issues with the laminated film 33.

[0089] The activation treatment step further includes setting the temperature distribution of the roller 12 surface in the width direction to preferably 3.5°C or less, more preferably 3°C or less, and even more preferably 2°C or less. This configuration further reduces temperature unevenness in the width direction of the roller 12 surface, thereby further reducing quality issues of the laminated film 33.

[0090] In the activation process, when the laminated film 33 is irradiated with energy rays multiple times, the energy ray irradiation is usually performed using a manufacturing apparatus equipped with two or more activation treatment devices. The energy ray irradiation can be performed while the laminated film passes through a single roller facing two or more activation treatment devices, or can be performed while the laminated film passes through multiple rollers using an apparatus equipped with two or more rollers facing one or more activation treatment devices.

[0091] This embodiment may further include a step of irradiating the activated laminating film 33 with energy rays, or a step of heating the activated laminating film 33. This configuration allows for more reliable activation of the adhesive. In this embodiment, the step of irradiating the activated laminating film 33 with energy rays is performed on a roller having a different configuration from the roller used in the activation step, differing from the energy irradiation in the activation step described above.

[0092] The heating step can be appropriately set depending on the types and thicknesses of the films and adhesives constituting the optical layered body, and is generally at 20 to 90°C, preferably 30 to 70°C, and more preferably 40 to 60°C.

[0093] The activation treatment step preferably further includes exhausting the air within the roller 12 to the outside of the roller 12. This configuration can further reduce temperature unevenness across the width of the roller 12 surface caused by the air within the roller 12, thereby further reducing quality issues with the laminated film 33. The air within the roller 12 is preferably exhausted to the outside of the roller 12 from the downstream side of the heat medium flow path.

[0094] It should be noted that the manufacturing method disclosed herein is not limited to the above-mentioned embodiments, and the design can be changed without departing from the scope of the present disclosure. For example, the manufacturing method disclosed herein is not limited to using Figure 1 It can be implemented by the manufacturing device 1, and can also be implemented by using other different devices.

[0095] (Example)

[0096] Next, examples will be described.

[0097] (1st film)

[0098] A long polyvinyl alcohol [PVA] film (thickness 20 μm, average polymerization degree of about 2400, saponification degree of 99.9 mol % or more) was uniaxially stretched to about 6 times by dry stretching, and then immersed in pure water at 40°C for 40 seconds while maintaining the tension.

[0099] Then, the film was dyed by being immersed in a dyeing aqueous solution at 28° C. having a mass ratio of iodine / potassium iodide / water of 0.044 / 5.7 / 100 for 30 seconds.

[0100] Then, the dyed film was immersed in a 70° C. boric acid aqueous solution having a mass ratio of potassium iodide / boric acid / water of 11.0 / 6.2 / 100 for 120 seconds to perform a cross-linking treatment.

[0101] The cross-linked film was then washed with pure water at 8°C for 15 seconds, dried at 60°C for 50 seconds, and then dried at 75°C for 20 seconds while maintaining a tension of 300 N / m. This produced a polarizing film (1300 mm in width) with a thickness of 7 μm and oriented iodine adsorbed on a PVA film.

[0102] A cycloolefin resin film (COP, ZF-14 manufactured by ZEON Corporation, Japan, non-UV absorbing, 13 μm thick) was prepared as a protective film. A water-based adhesive was injected between the resulting polarizing film and the cycloolefin resin film, and the films were laminated using a nip roller. While maintaining a tension of 430 N / m, the resulting laminate was dried at 60°C for 2 minutes to obtain a first film comprising 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.

[0103] The aqueous adhesive was prepared by adding 3 parts by mass of carboxyl-modified polyvinyl alcohol (Kuraray Poval (registered trademark) KL318, manufactured by Kuraray Co., Ltd.) and 1.5 parts by mass of a water-soluble polyamide epoxy resin (Sumirez Resin (registered trademark) 650, manufactured by Taoka Chemical Industry Co., Ltd.; a 30% solids aqueous solution) to 100 parts by mass of water.

[0104] (Second film)

[0105] As a transparent film, a long film (1340 mm in width) made of polyethylene terephthalate film with a thickness of 38 μm was prepared. The alignment layer composition was applied to one side of the transparent film so that the film thickness was 3 μm and the accumulated light intensity was 20 mJ / cm 2 The alignment layer is formed by irradiating ultraviolet rays.

[0106] It should be noted that 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% relative to the total mass of the resulting mixture.

[0107] 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.

[0108] To prepare the liquid crystal composition, a mixed heat medium containing methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), and cyclohexanone (CHN) with a boiling point of 155°C at a mass ratio (MEK:MIBK:CHN) of 35:30:35 was used as a solvent. The liquid crystal composition, prepared to a solids content of 1 to 1.5 g per 100 g of the composition, was then applied to the alignment layer.

[0109] After applying the liquid crystal composition onto the alignment layer, the resulting coating layer was dried at 75°C for 120 seconds. Subsequently, the liquid crystal compound was polymerized and cured by ultraviolet (UV) irradiation. This procedure yielded a second film consisting of a retardation layer, an alignment layer, and a transparent film. The retardation layer satisfied the relationship nz>nx=ny and was a positive C layer. The combined thickness of the retardation layer and alignment layer was 4 μm.

[0110] (Method for producing coating layer-forming composition)

[0111] As the coating layer-forming composition, an adhesive was used which was obtained by mixing the respective materials in the ratios shown in the following Table 1. In Table 1, the ratios of the respective materials are shown in parts by mass.

[0112]

Table 1

[0113] Number of copies Compound 1 70 Compound 2 20 Compound 3 10 initiator 4.5 sensitizers 2 Leveling agent 0.25 total 106.75

[0114] The details of the compounds in Table 1 are shown below.

[0115] Compound 1:

[0116] [Chemistry 1]

[0117]

[0118] 3',4'-Epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate ("CEL2021P" manufactured by Daicel Chemical Industries, Ltd., alicyclic diepoxy)

[0119] Compound 2:

[0120] [Chemistry 2]

[0121]

[0122] Neopentyl glycol diglycidyl ether (NPGDGE) ("EX-211" manufactured by Nagase ChemteX Co., Ltd., diepoxy)

[0123] Compound 3:

[0124] [Chemistry 3]

[0125]

[0126] 2-Ethylhexyl glycidyl ether (EHGE) (manufactured by Tokyo Chemical Industry Co., Ltd., monoepoxy)

[0127] Initiator: Cationic initiator SP-500 manufactured by ADEKA Corporation (solid content 2.25 parts)

[0128] Sensitizer: DEN, a sensitizer manufactured by Kawasaki Chemicals Co., Ltd.

[0129] Leveling agent: Leveling agent KRM-430 manufactured by ADEKA Co., Ltd.

[0130] (First Production Example of an Optical Layered Body)

[0131] While continuously conveying a first film (1340 mm width) and a second film (1340 mm width), the polarizer layer of the first film and the retardation layer of the second film were subjected to corona treatment. After the adhesive was applied to the corona-treated surface of the first film using a coater (bar coater) while the first and second films were continuously conveyed, the polarizer layer of the first film and the retardation layer of the second film were superimposed and passed between a pair of laminating rollers to obtain a laminated film having a layer structure of first film / coating layer / second film.

[0132] The obtained laminated film was conveyed at a speed of 10 m / min while the laminated film was subjected to a light beam so as to have a cumulative light intensity of 250 mJ / cm 2 In the method of (UVB)), ultraviolet rays were irradiated from an activation treatment device while being brought into close contact with a roll to cure the adhesive, thereby obtaining an optical layered body. A high-pressure mercury lamp manufactured by EYE GRAPHICS was used as the activation treatment device.

[0133] (Calculation method of the above formula (1) and the above formula (2))

[0134] Next, the calculation method of the above formula (1) and the above formula (2) will be described. Hereinafter, the description will be made based on specific examples.

[0135] 1. Roller and heat medium flow rate inside the roller

[0136] (1) A 200φ double-tube roller and a 250φ single-tube roller were used.

[0137] The 200-diameter double-tube roller consists of an outer tube and an inner tube made of rolled steel (SM490A), with a heat medium flowing between the outer and inner tubes. The roller has a diameter of 200 mm and a length of 1350 mm.

[0138] The 250φ single-tube roller is made of a single tube made of rolled steel (SM490A), with a heat medium flowing through the tube. The roller has a diameter of 250mm and a length of 1200mm.

[0139] Thereafter, the cross-sectional areas of the flow paths in these rollers are determined.

[0140] 200Φ double tube roller,

[0141] (0.089×0.089×π)-(0.075×0.075×π)=0.00721m 2

[0142] 250Φ single tube roller,

[0143] ((0.178×0.178×π)=0.0406m 2

[0144] (2) The flow rate is measured using a flow meter (clamp-on flow sensor: manufactured by KEYENCE). The flow velocity at each flow rate is determined based on the measured flow rate and the calculated flow path cross-sectional area within the roller.

[0145] The flow rate when water at 20° C. was allowed to flow through the roller at various flow rates was calculated using the following formula.

[0146] “Flow rate (m / s) = flow rate (L / min) / 60 / 1000 / cross-sectional area of ​​flow path in roller (m 2 )”

[0147] Flow rate when using a 200Φ double-tube roller:

[0148] Flow rate at 25 L / min (m / s) = 25 / 60 / 1000 / 0.007213 = 0.0578

[0149] Flow rate at 35 L / min (m / s) = 35 / 60 / 1000 / 0.007213 = 0.0809

[0150] Flow rate at 60 L / min (m / s) = 60 / 60 / 1000 / 0.007213 = 0.139

[0151] Flow rate at 87 L / min (m / s) = 87 / 60 / 1000 / 0.007213 = 0.201

[0152] Flow rate when using a 250Φ single-tube roller:

[0153] Flow rate at 25 L / min (m / s) = 25 / 60 / 1000 / 0.04062 = 0.0103

[0154] Flow rate at 55 L / min (m / s) = 55 / 60 / 1000 / 0.04062 = 0.0226

[0155] 2. Height of air layer at each flow rate

[0156] (1) Calculate the height of the air layer within the roller based on the flow rate. Since the roller used is opaque, a transparent acrylic roller was used to allow the water within the roller to be visible. The height of the air layer was measured with a ruler and magnified for a 200 Φ double tube and a 250 Φ single tube.

[0157] As a transparent acrylic roller, a 150-diameter acrylic double-tube roller ( Figure 2A and Figure 2B ) and a 150φ acrylic single tube roller with a roller diameter of 150mm and a length of 300mm ( Figure 3A and Figure 3B ) These two types were used to measure the height of the air layer based on each flow rate.

[0158] Figure 2A This is a cross-sectional view along the axis of a 150φ acrylic double-tube roller. Figure 2B yes Figure 2A A-A cross-sectional view of the Figure 2A and Figure 2B As shown, the double tube roller 50 is formed by an outer tube 51 and an inner tube 52. The double tube roller 50 has a heat medium flow path 55 through which heat medium flows. The heat medium flow path 55, viewed from the axial direction of the roller 50, has a first annular flow path 55a located between the outer tube 51 and the inner tube 52, a plurality of second flow paths 55b extending radially from the axis of the roller 50 at one end side of the axial direction of the roller 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 roller 50 at the other end side of the axial direction of the roller 50 and communicating with the other end side of the first flow path 55a. The heat medium is as Figure 2A As shown by the dotted arrows, the liquid passes through the second flow path 55b, the first flow path 55a, and the third flow path 55c in sequence from the inlet of the roller 50 and is discharged from the outlet of the roller 50.

[0159] Figure 3AThis is a cross-sectional view along the axis of a 150φ acrylic single tube roller. Figure 3B yes Figure 3A A-A cross-sectional view of the Figure 3A and Figure 3B As shown, the single tube roller 60 is formed by the outer tube 61. The single tube roller 60 has a heat medium flow path 65 through which the heat medium flows. That is, the heat medium flow path 65 is formed by the space inside the outer tube 61. Figure 3A As shown by the dotted arrow, the heat medium passes through the heat medium flow path 65 from the inlet of the roller 60 and is discharged from the outlet of the roller 60.

[0160] (2) The height of the air layer at each flow rate was measured using the transparent rollers 50 and 60, and the results were shown in FIG. Figure 4 in the curve diagram. Figure 4 In the graph, circular marks indicate the measured values ​​of a 150φ acrylic double-tube roller, and triangular marks indicate the measured values ​​of a 150φ acrylic single-tube roller. The horizontal axis indicates the flow rate of the heat medium (m / s), and the vertical axis indicates the height of the air layer (mm).

[0161] from Figure 4 Clearly, the air layer heights are roughly the same at the same flow rate in both the 150φ acrylic double-tube roller and the 150φ acrylic single-tube roller. This suggests that when the same heat medium flows through rollers of the same diameter at the same flow rate, the air layer height remains constant regardless of the roller's internal structure.

[0162] (3) The measurement results of the transparent roller were magnified, and the height of the air layer at each flow rate for the 200Φ double-tube roller and the 250Φ single-tube roller was calculated.

[0163] Specifically, use Figure 5 The following describes the magnification and conversion of the height of the air layer. Figure 5 As shown, the height of the air layer for the 150Φ acrylic double-tube roller is h (mm), and the height of the air layer for the 200Φ double-tube roller is h' (mm). With this arrangement, h' = h × (178 / 128). The height of the air layer when using the 200Φ double-tube roller is calculated as follows.

[0164] Air layer height (mm) at 25 L / min (flow rate 0.058 m / s) = 6.4 mm × (178 / 128) = 8.9 mm

[0165] Air layer height (mm) at 35 L / min (flow rate 0.081 m / s) = 2.6 mm × (178 / 128) = 3.6 mm

[0166] Note that at 60 L / min and 87 L / min, since the flow rate is greater than 0.1 m / s as determined in 1.(2) above, intermittent flow occurs and the height of the air layer is 0 mm.

[0167] Similarly, the height of the air layer when a 250φ single-tube roller is used is calculated as follows.

[0168] Air layer height (mm) at 25 L / min (flow rate 0.010 m / s) = 49 mm × (228 / 128) = 87.3 mm

[0169] Air layer height (mm) at 55 L / min (flow rate 0.023 m / s) = 34 mm × (228 / 128) = 60.6 mm

[0170] 3. The amount of heat medium (water) and heat capacity in the roller

[0171] (1) Based on the above-mentioned air layer height, the amount of heat medium in the roller at each flow rate is determined.

[0172] At this time, the cross-sectional area of ​​the air layer is calculated using the following formula for the area of ​​an arc.

[0173]

[0174] [S: cross-sectional area of ​​the air layer, r: roller radius, h: air layer height, θ: θ = 2acos (1-h / r)]

[0175] The amount of heat medium in the double tube roller is calculated according to the following formula:

[0176] [(cross-sectional area of ​​outer tube) - (cross-sectional area of ​​inner tube) - (cross-sectional area of ​​air layer)] x (length of roller).

[0177] The amount of heat medium in the single tube roller is calculated according to the following formula:

[0178] [(cross-sectional area of ​​roller) - (cross-sectional area of ​​air layer)] x (length of roller).

[0179] When using a 200Φ double-tube roller, the amount of heat medium in the roller is:

[0180] The amount of heat medium in the roller at 25L / min (L) = 9.6 (L)

[0181] The amount of heat medium in the roller at 35L / min (L) = 10.1 (L)

[0182] The amount of heat medium in the roller at 60L / min and 87L / min (L) = 11.0 (L) (full water state)

[0183] When using a 250Φ single-tube roller, the amount of heat medium in the roller is:

[0184] The amount of heat medium in the roller at 25L / min (L) = 32 (L)

[0185] The amount of heat medium in the roller at 55L / min (L) = 38 (L)

[0186] (2) The heat capacity was calculated based on the amount of heat medium in the roller. The heat medium was water, and the specific heat of water was 4.18 (kJ / K·L).

[0187] Heat capacity when using a 200Φ double-tube roller:

[0188] Heat capacity at 25 L / min (kJ / K) = 9.6 (L) × 4.18 = 40 (kJ / K)

[0189] Heat capacity at 35 L / min (kJ / K) = 10.1 (L) × 4.18 = 42 (kJ / K)

[0190] Heat capacity at 60L / min (kJ / K) = 11(L) × 4.18 = 46(kJ / K)

[0191] Heat capacity at 87 L / min (kJ / K) = 11 (L) × 4.18 = 46 (kJ / K)

[0192] Heat capacity when using a 250Φ single tube roller:

[0193] Heat capacity at 25 L / min (kJ / K) = 32 (L) × 4.18 = 134 (kJ / K)

[0194] Heat capacity at 55 L / min (kJ / K) = 38 (L) × 4.18 = 159 (kJ / K)

[0195] 4. Measurement of temperature distribution on the roller surface during UV irradiation

[0196] (1) A UV lamp (EYE GRAPHICS Co., Ltd., high-pressure mercury) was used as an activation treatment device, with a UVB light dose of 506 mJ / cm 2 , illumination 792mW / cm 2 The roller surface temperature was adjusted to 20° C. under the conditions of irradiation. After the temperature stabilized, the temperature was measured at a predetermined position in the width direction of the roller surface. The roller surface temperature was measured using ST-100 (Rika Kogyo Co., Ltd.).

[0197] Specifically, if Figure 6As shown, the temperature was measured at positions a to e in the width direction of the surface of roller 70. Position a was 220 mm from the drive side of roller 70, position b was 545 mm from the drive side of roller 70, position c was 675 mm from the drive side of roller 70, position d was 805 mm from the drive side of roller 70, and position e was 1130 mm from the drive side of roller 70.

[0198] The results are expressed in Figure 7 and Figure 8 middle. Figure 7 The temperature at positions a to e in the width direction of the roll when a 200φ double-tube roll is used is shown. Figure 7 In the figure, the circular mark indicates the measured value at 25 L / min, the triangular mark indicates the measured value at 35 L / min, the quadrilateral mark indicates the measured value at 60 L / min, and the diamond mark indicates the measured value at 87 L / min. Figure 8 The temperatures at positions a to e in the width direction of the roll when a 250φ single-tube roll is used are shown. Figure 8 In the figure, the circular mark indicates the measured value at 25 L / min, and the triangular mark indicates the measured value at 55 L / min.

[0199] (2) According to Figure 7 and Figure 8 The maximum temperature difference across the width of the roll surface is calculated from the results. Specifically, the maximum temperature difference across the roll surface is the value obtained by subtracting the minimum temperature across the width of the roll surface from the maximum temperature across the width of the roll surface. While the maximum temperature difference is expressed in degrees Celsius here, it can also be expressed in degrees Celsius. This also applies to the following description.

[0200] The maximum temperature difference between the measurement points when using a 200Φ double-tube roller is as follows.

[0201] Temperature difference at 25L / min (℃): 5.7 (℃)

[0202] Temperature difference at 35L / min (℃): 5.0 (℃)

[0203] Temperature difference at 60L / min (℃): 3.1 (℃)

[0204] Temperature difference at 87L / min (℃): 2.0 (℃)

[0205] The maximum temperature difference between the measurement points when using a 250Φ single-tube roller is as follows.

[0206] Temperature difference at 25L / min (℃): 1.7 (℃)

[0207] Temperature difference at 55L / min (℃): 1.0 (℃)

[0208] 5. The heat of the heat medium in the roller, the heat capacity of the heat medium in the roller, and the amount of heat medium in the roller

[0209] (1) Using the heat capacity (kJ / K) calculated based on the amount of heat medium in the roller and the measured maximum roller temperature difference (°C), the amount of heat (kJ) applied to the heat medium in the roller due to the maximum roller temperature difference was calculated using the following formula.

[0210] Heat (kJ) = Heat capacity based on the amount of heat medium in the roller (kJ / K) × Maximum roller temperature difference (°C)

[0211] Here, in the case of a 200Φ double-tube roller and a 250Φ single-tube roller, at a flow rate of 25 L / min,

[0212] 200Φ double-tube roller: 40 (kJ / K) × 5.7 (°C) = 228 (kJ)

[0213] 250Φ single tube roller: 134 (kJ / K) × 1.7 (°C) = 228 (kJ)

[0214] It can be seen that when the flow rate is 25 L / min, the amount of heat applied to the heat medium in the roller is constant at 228 kJ regardless of the roller shape.

[0215] (2) Based on the heat of the heat medium in the roller generated by the maximum roller temperature difference, the heat capacity (kJ / K) of the heat medium in the roller and the amount of heat medium (water) in the roller (L) when the maximum roller temperature difference is 3.0°C, 2.0°C, and 1.0°C are calculated.

[0216] When the maximum temperature difference is 3.0°C: Heat capacity (kJ / K) = 228 (kJ) / 3.0 (°C) = 76 (kJ / K)

[0217] Heat medium volume in roller (L) = 76 (kJ / K) / 4.18 (kJ / K·L) = 18.2 (L)

[0218] When the maximum temperature difference is 2.0°C: Heat capacity (kJ / K) = 228 (kJ) / 2.0 (°C) = 114 (kJ / K)

[0219] Heat medium volume in roller (L) = 114 (kJ / K) / 4.18 (kJ / K·L) = 27.3 (L)

[0220] When the maximum temperature difference is 1.0°C: Heat capacity (kJ / K) = 228 (kJ) / 1.0 (°C) = 228 (kJ / K)

[0221] Heat medium volume in roller (L) = 228 (kJ / K) / 4.18 (kJ / K·L) = 54.5 (L)

[0222] (3) Based on the results of 3. (1) and 5. (1) (2) above, the relationship between the heat amount X1 (kJ) of the heat medium in the roller generated by the maximum roller temperature difference, the heat capacity X2 (kJ / K) of the heat medium in the roller, the amount of heat medium in the roller (L), and the maximum roller temperature difference (°C) when the flow rate is 25 L / min is shown in Table 2 below.

[0223]

Table 2

[0224]

[0225] As shown in Table 2, number 1 represents the measured value for a 200Φ double-tube roller, and number 2 represents the measured value for a 250Φ single-tube roller. Numbers 3, 4, and 5 represent calculated values. Note that in Table 2, when using a 200Φ double-tube roller, the maximum capacity of the heat medium within the roller is 11.0 L, so numbers 2 through 5 are not applicable.

[0226] (4) Using the same method as that for the flow rate of 25 L / min, the amount of heat applied to the heat medium in the roller due to the maximum roller temperature difference at a flow rate of 60 L / min was calculated.

[0227] 200Φ double-tube roller: 46 (kJ / K) × 3.1 (°C) = 143 (kJ).

[0228] Based on this heat quantity, the heat capacity (kJ / K) of the heat medium in the roller and the amount (L) of the heat medium in the roller when the maximum roller temperature differences were 3.0°C, 2.0°C, and 1.0°C were calculated.

[0229] When the maximum temperature difference is 3.0°C: Heat capacity (kJ / K) = 143 (kJ) / 3.0 (°C) = 48 (kJ / K)

[0230] Heat medium volume in roller (L) = 48 (kJ / K) / 4.18 (kJ / K·L) = 11.5 (L)

[0231] When the maximum temperature difference is 2.0°C: Heat capacity (kJ / K) = 143 (kJ) / 2.0 (°C) = 73 (kJ / K)

[0232] Heat medium volume in roller (L) = 73 (kJ / K) / 4.18 (kJ / K·L) = 17.5 (L)

[0233] When the maximum temperature difference is 1.0°C: Heat capacity (kJ / K) = 143 (kJ) / 1.0 (°C) = 143 (kJ / K)

[0234] Heat medium volume in roller (L) = 143 (kJ / K) / 4.18 (kJ / K·L) = 34.2 (L)

[0235] Based on these results, the relationship between the heat amount X1 (kJ) of the heat medium in the roller generated by the maximum roller temperature difference, the heat capacity X2 (kJ / K) of the heat medium in the roller, the amount of heat medium in the roller (L), and the maximum roller temperature difference (°C) at a flow rate of 60 L / min is shown in Table 3 below.

[0236]

Table 3

[0237]

[0238] As shown in Table 3, number 1 represents the measured value for a 200Φ double-tube roller, while numbers 2, 3, and 4 represent calculated values. Note that in Table 3, when using a 200Φ double-tube roller, the maximum capacity of the heat medium within the roller (roller volume) is 11.0 L, so numbers 2 through 4 are not applicable.

[0239] 6. Regarding the above formula (1) and the above formula (2)

[0240] (1) As is clear from Tables 2 and 3 above, (X1 / X2) in Formula (1) represents the maximum roller temperature difference. That is, Formula (1) indicates that the maximum roller temperature difference is greater than 0 K and is 3.5 K or less.

[0241] In equation (2), (X2 / Sc) represents the amount of heat medium within the roller. Sc represents the specific heat of the heat medium (in Tables 2 and 3, it is the specific heat of water, 4.18 (kJ / K·L)). The lower limit of equation (2), (X1 / (3.5×Sc)), represents the amount of heat medium required within the roller when the maximum roller temperature difference is 3.5 K. In other words, equation (2) indicates that the amount of heat medium within the roller must be greater than the amount required when the maximum roller temperature difference is 3.5 K and less than the roller volume.

[0242] (2) The following explains how satisfying equation (1) makes the reaction rate of the adhesive substantially uniform across the width of the roller. Table 4 shows the roller minimum temperature Tmin, the roller maximum temperature Tmax, the roller maximum temperature difference ΔT (Tmax - Tmin), the reaction rate constant kmin at the roller minimum temperature, the reaction rate constant kmax at the roller maximum temperature, and the reaction rate ratio kmax / kmin of the roller maximum temperature to the roller minimum temperature.

[0243] The reaction rate constant k is calculated according to the Arrhenius formula: k = A exp(-Ea / RT).

[0244] (A: constant, Ea: activation energy, R: gas constant, T: absolute temperature (K))

[0245] The activation energy Ea was set to 59400 (J / mol) based on the activation energy value of epoxy resins described in a polymer handbook.

[0246] [Table 4]

[0247]

[0248] As shown in Table 4, number 1 represents the measured value for a 200φ double-tube roller at a flow rate of 25 L / min, and number 2 represents the measured value for a 250φ single-tube roller at a flow rate of 25 L / min. Numbers 3, 4, and 5 represent calculated values ​​with Tmin fixed at 25°C.

[0249] Table 4 clearly shows that the greater the maximum roller temperature difference ΔT, the greater the reaction rate ratio. In other words, the temperature unevenness across the width of the roller surface causes differences in the adhesive's reaction rate across the width of the roller. This difference in adhesive reaction rate affects the quality of the laminated film. Furthermore, when the maximum roller temperature difference is greater than 0 K and less than 3.5 K, that is, when equation (1) is satisfied, the reaction rate ratio is greater than 1 and less than 1.32, minimizing the difference in reaction rate and, consequently, reducing quality issues with the laminated film.

[0250] The maximum roller temperature difference is preferably 3K or less, more preferably 2K or less, so that the reaction rate ratio can be further reduced, thereby further reducing the quality problems of the laminated film.

[0251] (3) Furthermore, when equation (2) is satisfied, that is, when the amount of heat medium flowing through the roller is such that the maximum roller temperature difference is 3.5 K or less, the maximum roller temperature difference can be kept below 3.5 K. Consequently, the temperature unevenness across the width of the roller surface can be reduced, and the reaction rate of the adhesive can be made substantially uniform across the width of the laminated film, thereby reducing quality issues with the laminated film.

[0252] (Second Production Example of Optical Layered Body)

[0253] (1) Fabrication of λ / 2 Phase Difference Layer

[0254] The λ / 2 alignment treatment was performed by applying the aforementioned alignment layer composition to a triacetylcellulose film having a thickness of 80 μm and a width of 1340 mm and drying the film. Subsequently, 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. A λ / 2 liquid crystal layer having a thickness of 2 μm was thus formed on the alignment surface.

[0255] (2) Fabrication of λ / 4 Phase Difference Layer

[0256] The above-mentioned composition for the alignment layer is applied to a triacetyl cellulose film having a thickness of 80 μm and a width of 1340 mm and dried, and a coating liquid containing a rod-shaped and polymerizable nematic liquid crystal monomer is applied to the transparent resin substrate for the λ / 4 alignment thus obtained, and the film is cured 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 the λ / 4 alignment.

[0257] (3) Production of optical laminates

[0258] The liquid crystal layer side of each of the λ / 2 retardation layer and the λ / 4 retardation layer was subjected to a corona discharge treatment at an output power intensity of 800W.

[0259] Then, use Figure 1 The obtained λ / 2 retardation layer and the obtained λ / 4 retardation layer were laminated together using the manufacturing apparatus shown above via the coating layer-forming composition (cationically polymerizable, viscosity 40 mPa·s) used in the above-mentioned first manufacturing example.

[0260] Specifically, the λ / 2 phase difference layer (equivalent to Figure 1 The slow axis of the symbol 31) and the λ / 4 phase difference layer (equivalent to Figure 1 The laminating device is configured in such a manner that the angle formed by the slow axis of the λ / 2 phase difference layer is 60°, and the coating layer forming composition is applied to the λ / 2 liquid crystal layer side of the λ / 2 phase difference layer so as to have a thickness of 3 μm while conveying each phase difference layer. Figure 1 The λ / 4 liquid crystal layer and the λ / 2 liquid crystal layer were laminated together (see symbols 21 and 22). The laminated body obtained by lamination was conveyed and irradiated from the λ / 4 phase difference layer side of the laminated body on a double tube roller set to the conditions described below using an ultraviolet irradiation device (manufactured by Fusion UV Systems Co., Ltd.) at a cumulative light dose of 400 mJ / cm 2 (UV-B) The adhesive is cured by ultraviolet irradiation to obtain an optical laminate having a laminate structure of λ / 2 retardation layer / adhesive layer / λ / 4 retardation layer.

[0261] In the second manufacturing example, the following double tube rollers were used:

[0262] (1) Use the following roller (equivalent to Figure 1 Symbol 12) is a double tube roller, that is, it is made of rolled steel (SM490A), formed by an outer tube (thickness: 12 mm) and an inner tube (thickness: 7.5 mm), has a structure in which heat medium flows between the outer tube and the inner tube, the outer diameter of the roller is 200 mm, and the length of the roller is 1350 mm.

[0263] (2) Water regulated to 25°C (Condition 2), 50°C (Conditions 5 to 7), and 75°C (Conditions 3 and 4) was used as the heat medium. During ultraviolet irradiation, the heat medium was circulated within the double-tube roller to regulate the surface temperature of the roller.

[0264] (3) The flow rate of the heat medium was measured using a flow meter (clamp-type flow sensor: manufactured by KEYENCE) at a predetermined position in the width direction of the regulated roller surface ( Figure 6 Temperatures were measured at positions a to e shown using an ST-100 (Rika Kogyo Co., Ltd.). Position a was 220 mm from the drive side of roller 70, position b was 545 mm from the drive side of roller 70, position c was 675 mm from the drive side of roller 70, position d was 805 mm from the drive side of roller 70, and position e was 1130 mm from the drive side of roller 70.

[0265] The maximum temperature difference between the measurement points is shown below. The flow rate is 25 L / min.

[0266] Temperature difference (°C) under condition 2 with temperature adjustment (water temperature 25°C): 32.7-27.0=5.7°C

[0267] Temperature difference (°C) under condition 3 with temperature adjustment (water temperature 75°C): 82.7-77.0=5.7°C

[0268] Temperature difference (°C) under condition 4 with temperature adjustment (water temperature 75°C): 80.5-77.0=3.5°C

[0269] Temperature difference (°C) when condition 5 is temperature controlled (water temperature 50°C): 55.5-52.0=3.5°C

[0270] Temperature difference (°C) when condition 6 is temperature controlled (water temperature 50°C): 53.7-52=1.7°C

[0271] Temperature difference (°C) when condition 7 is temperature controlled (water temperature 50°C): 53.0-52.0=1.0 (°C)

[0272] (4) The heat amount (kJ) of the heat medium in the roller caused by the maximum temperature difference in the width direction of the roller surface and the heat capacity (kJ / K) of the heat medium in the roller are shown in Table 5. The values ​​of each heat capacity were calculated using the same procedure as the data shown in Table 3.

[0273] It should be noted that, as a comparative manufacturing example, Figure 1 The manufacturing apparatus shown does not include the roller 12 , and an optical layered body was manufactured using the same steps and conditions (hereinafter also referred to as “condition 1”) as those in the second manufacturing example.

[0274] (Evaluation of the optical layered body obtained in the second production example)

[0275] A test piece measuring 1340 mm wide and 300 mm long was cut from the resulting optical layered product. Each test piece was irradiated with light at an illuminance of 2600 lx and visually observed for the presence of film defects (white spots). "Presence" of film defects refers to the observation of numerous fine white spots, while "absence" of film defects refers to the observation of no white spots.

[0276] The results of film defects under the above-mentioned conditions 1 to 7 are shown in the following Table 5. In Table 5, the conditions 1 to 7 are represented by numbers 1 to 7. Figure 1 The roller 12 shown is used as a temperature control roller.

[0277] [Table 5]

[0278]

Claims

1. A method for producing an optical laminate comprising: The manufacturing method comprises: A laminating step of laminating two different films via an energy ray activated adhesive to form a laminated film; an activation treatment step of irradiating the laminating film with energy rays on the roller while the laminating film is in contact with the roller to activate the adhesive; as well as The heating step is to heat the activated laminated film. The roller has a heat medium flow path inside which the heat medium flows. The manufacturing method performs the activation treatment step while circulating the heat medium in the heat medium flow path and maintaining the roller in a state satisfying the range of formula (1): Formula (1): 0<X1 / X2≤3.5 X1: The heat of the heat medium in the roller generated by the maximum temperature difference in the width direction of the roller surface, unit is KJ; X2: The heat capacity of the heat medium in the roller, unit is KJ / K, In the activation treatment step, at least one of the flow rate, flow rate, temperature, or amount of the heat medium in the roller is adjusted so as to be maintained within the range satisfying formula (1). In the heating step, the temperature on the laminating film is controlled to be 30 to 90°C.

2. The method for producing an optical layered body according to claim 1, wherein: The activation treatment step further includes circulating a heat medium within the range satisfying formula (2): Formula (2): X1 / (3.5×Sc)≤X2 / Sc≤V Sc: Specific heat of the heat medium, unit is kJ / K·L; V: Maximum capacity of the heat medium in the roller, unit is L.

3. The method for producing an optical layered body according to claim 1 or 2, wherein: The activation treatment step further includes an operation of setting the temperature distribution of the surface of the roller in the width direction to 3° C. or less.

4. The method for producing an optical layered body according to claim 1 or 2, wherein: The activation treatment step further includes exhausting the air in the roller to the outside of the roller from a downstream side of the heat medium flow path.

5. An apparatus for producing an optical laminate, comprising: a device for producing an optical laminate having at least one layer comprising an optical film; The manufacturing device comprises: a laminating device for laminating two different films via an energy ray-activated adhesive to form a laminated film; a roller in contact with the laminating film and having a heat medium flow path therein for circulating a heat medium; an activation treatment device for irradiating the laminating film with energy rays on the roller to perform activation treatment on the adhesive; as well as The control device controls the roller so as to maintain the roller within the range satisfying the formula (1) by adjusting at least one of the flow rate, flow rate, temperature, or amount of the heat medium in the roller when the activation treatment device is performing the activation treatment on the adhesive, and controls the roller so as to heat the activated film so as to achieve a temperature of 30 to 90° C. on the surface of the film. Formula (1): 0<X1 / X2≤3.5 X1: The amount of heat generated by the heat medium in the roller due to the maximum temperature difference in the width direction of the roller surface, in kJ; X2: The heat capacity of the heat medium in the roller, in kJ / K.

6. The manufacturing apparatus of the optical laminate according to claim 5, wherein When the activation treatment device is used to perform the activation treatment of the adhesive, the control device further controls the flow of the heat medium within a range satisfying the formula (2): Formula (2): X1 / (3.5×Sc)≤X2 / Sc≤V Sc: Specific heat of the heat medium, unit is kJ / K·L; V: Maximum capacity of the heat medium in the roller, unit is L.

7. The manufacturing apparatus of the optical laminate according to claim 5 or 6, wherein: When the activation treatment device is used to perform the activation treatment of the adhesive, the control device further controls so that the temperature distribution in the width direction of the surface of the roller is 3.5° C. or less.

8. The manufacturing apparatus of the optical laminate according to claim 5 or 6, wherein The roller further includes an exhaust air flow path on the downstream side of the heat medium flow path, which communicates with the heat medium flow path and exhausts air in the heat medium flow path to the outside of the roller.

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