Method for manufacturing optical laminate and apparatus for manufacturing optical laminate

Abstract

The present application provides a method for manufacturing an optical laminate and a device for manufacturing an optical laminate, which can reduce temperature unevenness in the width direction of the surface of a roll, thereby reducing problems of the quality of a bonded film. The method for manufacturing an optical laminate comprises a bonding step and a specific activation treatment step.

Description

Technical Field

[0001] This invention relates to a method for manufacturing optical laminates and an apparatus for manufacturing optical laminates. Background Technology

[0002] In the manufacture of optical laminates such as polarizing plates, after the optical films constituting the optical laminate are bonded together using an energy-ray activated adhesive, the resulting laminated film is transported while undergoing an activation process. This activation process is performed by irradiating the laminated film as it passes over rollers with energy rays. To avoid problems with the quality of the laminated film, such as deformation or uneven curing, the laminated film is usually cooled on cooled rollers while being irradiated with energy rays.

[0003] Conventionally, as a method for cooling rollers, for example, as shown in Japanese Patent Application Publication No. 2019-3210 (Patent Document 1), a heat medium is circulated inside the roller.

[0004] Existing technical documents

[0005] Patent documents

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

[0007] The problem that the invention aims to solve

[0008] However, when the heat medium flows through the roller as before, temperature unevenness may occur in the width direction of the roller surface. Moreover, the temperature unevenness in the width direction of the roller surface causes uneven reaction rate of the adhesive in the width direction of the laminated film, which may lead to quality problems of the laminated film.

[0009] Therefore, this disclosure provides a method and apparatus for manufacturing an optical laminate that reduces temperature unevenness in the width direction of the roller surface, thereby reducing the quality problems of the laminated film.

[0010] means for solving problems

[0011] Regarding the aforementioned problem, the inventors of this application discovered that temperature unevenness occurs due to the circulation of gas accompanying the heat medium, thereby completing the invention of this application.

[0012] The method for manufacturing the optical laminate of the present invention is a method for manufacturing an optical laminate having at least one layer comprising an optical film, the method comprising:

[0013] The lamination process involves bonding two dissimilar films together using an energy-ray activated adhesive to form a laminated film; and

[0014] The activation process involves activating the adhesive by irradiating the laminating film with energy rays while the laminating film is in contact with the roller.

[0015] The roller has a heat medium flow path inside, and a roller body with its center line aligned with the axis of rotation and its outer periphery extending in a cylindrical shape. The surface temperature of the roller is adjusted by a heat medium circulation mechanism that circulates the heat medium in the heat medium flow path.

[0016] The heat medium flow path includes: a main passage extending along the rotation axis in a manner corresponding to the entire area of ​​the outer peripheral surface of the roller body; an inlet passage extending along the rotation axis and communicating with the main passage to introduce the heat medium into the main passage; a first outlet passage extending along the rotation axis and communicating with the main passage to discharge the heat medium flowing through the main passage; and a second outlet passage, one end of which is downstream of the main passage and communicating with the main passage located near the outer peripheral surface, and the other end of which is communicating with the first outlet passage.

[0017] The activation process includes the operation of circulating a heat medium within the heat medium flow path while rotating the main body of the roller.

[0018] According to the method described, since the activation process includes the operation of circulating a heat medium in the heat medium flow path while rotating the main body of the roller, the heat medium can be circulated in the main body of the roller simultaneously with the gas in the main passage being discharged from the second discharge passage. This reduces temperature unevenness in the width direction of the roller surface caused by gas inside the roller, and makes the adhesive reaction rate approximately uniform in the width direction of the laminated film, thereby reducing quality problems with the laminated film.

[0019] Furthermore, the method for manufacturing the optical laminate of the present invention is a method for manufacturing an optical laminate having at least one layer comprising an optical film.

[0020] This manufacturing method has the following features:

[0021] The lamination process involves bonding two dissimilar films together using an energy-ray activated adhesive to form a laminated film; and

[0022] The activation process involves irradiating the laminating film with energy rays onto the laminating film on the roller while simultaneously bringing the laminating film into contact with the roller, thereby activating the adhesive.

[0023] The roller has a heat medium flow path inside, and a roller body with its center line aligned with the axis of rotation and its outer periphery extending in a cylindrical shape. The surface temperature of the roller is adjusted by a heat medium circulation mechanism that circulates the heat medium in the heat medium flow path.

[0024] The heat medium flow path includes: a main passage extending along the axis of rotation in a manner corresponding to the entire area of ​​the outer peripheral surface of the roller body; and a discharge passage discharging the heat medium flowing through the main passage.

[0025] The activation process includes the operation of circulating a heat medium in the heat medium flow path while rotating the main body of the roller, wherein the volume of the heat medium circulating in the main passage is maintained at more than 90% and less than 100% of the total volume of the main passage.

[0026] According to the method described, since the activation process includes the operation of circulating a hot medium in the hot medium flow path while rotating the main body of the roller, the volume of the hot medium circulating in the main passage is maintained at more than 90% and less than 100% of the total volume of the main passage. Therefore, the hot medium can be circulated in the main body of the roller while the gas in the main passage is discharged from the discharge passage. As a result, the temperature unevenness in the width direction of the roller surface caused by the gas in the roller can be reduced, and the reaction rate of the adhesive in the width direction of the laminated film can be made approximately uniform, thereby reducing the quality problems of the laminated film.

[0027] Preferably, in one embodiment of the method for manufacturing an optical laminate, the activation process is performed while maintaining the temperature distribution in the width direction of the surface of the roller body at 3.5°C or below.

[0028] According to the embodiment, since the activation process is performed while maintaining the temperature distribution in the width direction of the roller body surface at 3.5°C or below, 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] In one embodiment of the method for manufacturing an optical laminate, a step of irradiating an energy beam onto a bonding film 33 that has undergone an activation treatment is included.

[0030] According to the embodiment, since the step of irradiating the activated bonding film with energy rays is also included, the activation treatment of the adhesive can be performed more reliably.

[0031] Furthermore, as one aspect of the optical laminate manufacturing apparatus disclosed herein, it is an apparatus for manufacturing an optical laminate having at least one layer comprising an optical film.

[0032] The manufacturing apparatus includes:

[0033] A bonding device that bonds two different films together using an energy-ray activated adhesive to form a bonded film;

[0034] A roller that contacts the bonding film; and

[0035] An activation treatment apparatus that activates the adhesive by irradiating the laminating film onto the roller with energy rays.

[0036] The roller has a heat medium flow path inside, and a roller body with its center line aligned with the axis of rotation and its outer periphery extending in a cylindrical shape. The surface temperature of the roller is adjusted by a heat medium circulation mechanism that circulates the heat medium in the heat medium flow path.

[0037] The heat medium flow path includes: a main passage extending along the rotation axis in a manner corresponding to the entire area of ​​the outer peripheral surface of the roller body; an inlet passage extending along the rotation axis and communicating with the main passage to introduce the heat medium into the main passage; a first outlet passage extending along the rotation axis and communicating with the main passage to discharge the heat medium flowing through the main passage; and a second outlet passage, one end of which is downstream of the main passage and communicating with the main passage located near the outer peripheral surface, and the other end of which is communicating with the first outlet passage.

[0038] According to the method described, since the roller's heat medium flow path has a second discharge passage connected to the main passage, the heat medium can circulate within the roller body while the gas in the main passage is discharged through the second discharge passage. This reduces temperature unevenness in the width direction of the roller surface caused by gas within the roller, resulting in a more uniform adhesive reaction rate in the width direction of the laminated film, thereby reducing quality issues with the laminated film.

[0039] Preferably, in one embodiment of the optical laminate manufacturing apparatus, a control device is also provided, which controls the temperature distribution in the width direction of the surface of the roller body to be maintained at 3.5°C or below when the adhesive is activated using the activation treatment device.

[0040] According to the embodiment, by controlling the temperature distribution in the width direction of the surface of the roller body during the activation treatment of the adhesive using the activation treatment device, 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.

[0041] Preferably, in one embodiment of the optical laminate manufacturing apparatus,

[0042] The main body of the roller has an outer tube and an inner tube.

[0043] The space between the outer tube and the inner tube constitutes part of the heat medium flow path.

[0044] According to the described embodiment, since the space between the outer tube and the inner tube constitutes part of the heat medium flow path, it is possible to form a configuration in which the heat medium flows only in a portion of the space within the outer tube. Therefore, compared to a single-tube roller of the same diameter, less heat medium can be used and the flow rate can be increased.

[0045] Preferably, in one embodiment of the optical laminate manufacturing apparatus, two or more of the second discharge passages are provided.

[0046] According to the embodiment described, since there are two or more second discharge passages, gas can be discharged efficiently.

[0047] Preferably, in one embodiment of the optical laminate manufacturing apparatus, the second discharge passage is provided at equal intervals around the rotation axis.

[0048] According to the embodiment, since the gas remaining in the upper part of the roller passes through the second discharge passage at short intervals during the rotation of the roller, the discharge time of the gas remaining in the upper part of the main passage per revolution of the roller is increased, and the heat medium can be efficiently filled in the main passage.

[0049] Invention Effects

[0050] According to the optical laminate manufacturing method and apparatus disclosed herein, the temperature unevenness in the width direction of the roller surface can be reduced, thereby reducing quality problems of the laminated film. Attached Figure Description

[0051] Figure 1 This is a schematic diagram illustrating one embodiment of an apparatus for manufacturing optical laminates.

[0052] Figure 2 This is a schematic cross-sectional view of one embodiment of the roller.

[0053] Figure 3 yes Figure 2 A sectional view at line II-II.

[0054] Figure 4 yes Figure 2 Enlarged view of Part III.

[0055] Figure 5A This is a schematic cross-sectional view illustrating other embodiments of the roller.

[0056] Figure 5B yes Figure 5AAA sectional view.

[0057] Explanation of reference numerals in the attached figures

[0058] 1. Roller assembly, 2. Roller, 3. Heat medium circulation unit (heat medium circulation mechanism), 4. Roller body, 4a. Outer peripheral surface, 4b. End surface, 5. Shaft, 10. Heat medium flow path, 10a. Main passage, 10b. Inlet passage, 10c. First outlet passage, 10d. Second outlet passage, 15. Optical laminate manufacturing apparatus, 16. Laminating apparatus, 17. Control device, 11. Adhesive coating apparatus, 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 Lamination film, 34 Optical laminate (polarizing plate), 50 Roller, 51 Outer tube (roller body), 51a Outer peripheral surface, 52 Inner tube (roller body), 53 First shaft, 54 Second shaft, 55 Heat medium flow path, 55a First passage (main passage), 55b Second passage (main passage), 55c Third passage (main passage), 55d Inlet passage, 55e First outlet passage, 55f Second outlet passage, C1 Rotating shaft. Detailed Implementation

[0059] Hereinafter, a method for manufacturing an optical laminate and an apparatus for manufacturing an optical laminate, which are embodiments of the present disclosure, will be described in detail with reference to the illustrated embodiments. It should be noted that the accompanying drawings include some schematic diagrams and may not always reflect actual dimensions or proportions.

[0060] (Implementation Method)

[0061] (Optical laminate manufacturing apparatus)

[0062] Figure 1 This is a schematic diagram illustrating one embodiment of an apparatus for manufacturing optical laminates. (As shown) Figure 1 As shown, the optical laminate manufacturing apparatus 15 includes: a bonding device 16 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 2 that contacts the bonding film 33; an activation processing device 13 for irradiating the bonding film 33 with energy rays to form an optical laminate 34; and a control device 17 for controlling the roller 2.

[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. These films are along... Figure 1 Transport in the direction indicated by the arrow.

[0064] Optical films are resin films that exhibit optical properties, such as polarizing films and phase refraction films. Polarizing films, for example, are formed by dyeing a uniaxially stretched polyvinyl alcohol film with iodine or dichroic dyes, followed by boric acid treatment.

[0065] Examples of transparent films 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. Resin films with low moisture permeability are preferred. Cellulose acetate-based resin films, such as triacetyl cellulose films and diacetyl cellulose films, can also be used as transparent films.

[0066] Optical films can be single layers or laminates. There are no particular limitations on the type of optical film, as long as it exhibits optical properties. The resulting optical laminate can be an optical laminate containing a film that does not exhibit optical properties, or, if it does exhibit optical properties, it can be an optical laminate containing a phase retardation film, a protective film, the aforementioned polarizing film, or a thermoplastic resin. In other words, an optical laminate only needs to have at least one layer containing an optical film.

[0067] The bonding apparatus 16 includes an adhesive coating apparatus 11 for coating an adhesive onto one side of the first film 31, and a first bonding roller 21 and a second bonding roller 22 for overlapping and bonding the first film 31 and the second film 32 with the adhesive. The adhesive is an energy ray activated adhesive.

[0068] From the perspectives of weather resistance, refractive index, and cationic polymerizability, adhesives, for example, use epoxy resins that do not contain aromatic rings within the molecule. Examples of epoxy resins used include hydrogenated epoxy resins, alicyclic epoxy resins, and aliphatic epoxy resins. Polymerization initiators are added to epoxy resins, such as photocationic polymerization initiators for polymerization using active energy rays, thermocationic polymerization initiators for polymerization using heat, and other additives (sensitizers, etc.).

[0069] Roller 2 is driven to rotate so that its centerline is aligned with the axis of rotation, transporting the laminating film 33 while it comes into contact with the surface of roller 2. Roller 2 is in contact with laminating film 33. That is, when energy rays are irradiated onto laminating film 33 from activation treatment device 13, heat is not easily applied to laminating film 33 due to the contact between roller 2 and laminating film 33. Roller 2 has a heat medium flow path inside it, through which the heat medium flows, cooling laminating film 33. The heat medium is, for example, a refrigerant such as water.

[0070] Roller 2 has a main body that extends in a cylindrical shape on its outer periphery. The surface temperature of roller 2 is regulated by a heat medium circulation mechanism that circulates a heat medium in a heat medium flow path. The heat medium circulation mechanism is, for example, a heat medium circulation unit including a circulation pump, and is controlled by control device 17.

[0071] The hot medium flow path includes: a main passage extending along the axis of rotation in a manner corresponding to the entire area of ​​the outer peripheral surface of the roller body; an inlet passage extending along the axis of rotation and communicating with the main passage to introduce the hot medium into the main passage; a first outlet passage extending along the axis of rotation and communicating with the main passage to discharge the hot medium flowing through the main passage; and a second outlet passage, one end of which is downstream of the main passage and communicating with the main passage located near the outer peripheral surface, and the other end of which is communicating with the first outlet passage.

[0072] Since the heat medium flow path of roller 2 has a second discharge passage connected to the main passage, the heat medium can flow within the roller body while the gas in the main passage is discharged through the second discharge passage. The gas is, for example, air. The second discharge passage can discharge not only gas but also the heat medium. Therefore, the temperature unevenness in the width direction of the roller 2 surface caused by the gas inside roller 2 can be reduced, and the reaction rate of the adhesive in the width direction of the laminated film 33 can be made approximately uniform, thereby reducing quality problems with the laminated film 33.

[0073] In addition, since the second discharge passage is connected to the main passage located near the outer peripheral surface, when the rotation axis of the roller 2 is configured horizontally for use, the gas remaining on the outer peripheral surface side of the main passage can be effectively discharged from the second discharge passage.

[0074] In addition, since the second discharge passage is connected to the downstream side of the main passage, the gas can be discharged efficiently along with the flow of the heat medium.

[0075] The main body of the roller can be, for example, composed of a single outer tube, in which case the internal space of the outer tube forms part of the heat medium flow path (main passage). Alternatively, the main body of the roller can also be composed of a double tube consisting of an outer tube and an inner tube, in which case the space between the outer tube and the inner tube forms part of the heat medium flow path (main passage). Viewed from the rotation axis of roller 2, the space between the outer tube and the inner tube is formed in an annular shape.

[0076] An activation treatment device 13 is disposed facing the roller 2. The activation treatment device 13 irradiates the bonding film 33 onto the roller 2 with energy rays to activate the adhesive. That is, the activation treatment device 13 uses energy rays to polymerize and solidify the adhesive. Operating as described above, the optical laminate 34 formed by the activation treatment of the activation treatment device 13 is wound by the winding roller 20. It should be noted that the energy rays typically irradiate not only the roller 2 but also its periphery.

[0077] The activation treatment device 13 has a light emission distribution at wavelengths below 400 nm, and uses low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, chemical lamps, black light lamps, microwave-excited mercury lamps, metal halide lamps, etc.

[0078] Preferably, when activating the adhesive using the activation treatment device 13, the control device 17 controls the temperature distribution (maximum temperature difference) in the width direction of the roller body surface to be maintained at 3.5°C or less, more preferably 2°C or less. That is, the control device 17 preferably sets the difference between the maximum temperature and the minimum temperature in the width direction of the roller body surface to be 3.5°C or less. With this setting, temperature unevenness in the width direction of the roller 2 surface can be further reduced, thereby further reducing quality issues with the laminating film 33.

[0079] Specifically, the control device 17 is composed of a central processing unit. For example, the control device 17 controls the heat medium circulation mechanism to adjust the flow rate, flow rate, or amount of heat medium in the roller 2, thereby maintaining the temperature distribution in the width direction of the roller 2 surface at 3.5°C or below.

[0080] Preferably, the main body of the roller has an outer tube and an inner tube, and the space between the outer tube and the inner tube forms part of the heat medium flow path. According to this arrangement, since a configuration in which the heat medium flows only in a part of the space inside the outer tube can be formed, the amount of heat medium can be less and the flow rate can be increased compared to a single-tube roller 2 of the same diameter.

[0081] Preferably, two or more second discharge passages are provided. This arrangement increases the number of second discharge passages, allowing for efficient gas discharge. Preferably, the second discharge passages are arranged at equal intervals around the axis of rotation. With this arrangement, since each second discharge passage allows the gas remaining in the upper part of the roller to pass through at short intervals during the rotation of the roller 2, the discharge time of the gas remaining in the upper part of the main passage per revolution of the roller 2 is increased, allowing for efficient filling of the main passage with the heat medium.

[0082] It should be noted that the manufacturing apparatus disclosed herein is not limited to the embodiments described above, and modifications can be made without departing from the spirit of this disclosure. The manufacturing apparatus may include two or more activation treatment devices and rollers. In the manufacturing apparatus, multiple activation treatment devices may be arranged facing one roller.

[0083] (Manufacturing method of optical laminates)

[0084] Next, use Figure 1 One embodiment of the method for manufacturing an optical laminate will be described.

[0085] First, the first film 31 and the second film 32 are bonded together using an energy-ray activated adhesive to form a laminated film 33. This is called the bonding process. Then, while the laminated film 33 is in contact with the roller 2, energy rays are irradiated onto the laminated film 33 on the roller 2 to activate the adhesive. This is called the activation process.

[0086] Here, inside the roller 2, a heat medium flow path is provided for the flow of the heat medium. The roller 2 has a roller body whose center line is aligned with the axis of rotation and whose outer circumference extends in a cylindrical shape. The surface temperature of the roller 2 is regulated by a heat medium circulation mechanism that circulates the heat medium in the heat medium flow path.

[0087] The hot medium flow path includes: a main passage extending along the axis of rotation in a manner corresponding to the entire area of ​​the outer peripheral surface of the roller body; an inlet passage extending along the axis of rotation and communicating with the main passage to introduce the hot medium into the main passage; a first outlet passage extending along the axis of rotation and communicating with the main passage to discharge the hot medium flowing through the main passage; and a second outlet passage, one end of which is downstream of the main passage and communicating with the main passage located near the outer peripheral surface, and the other end of which is communicating with the first outlet passage.

[0088] In addition, the activation process includes the operation of circulating a heat medium in the heat medium flow path while rotating the main body of the roller.

[0089] According to this configuration, since the activation process includes the operation of circulating a heat medium in the heat medium flow path while rotating the roller body, the heat medium can be circulated in the roller body simultaneously with the gas in the main passage being discharged from the second discharge passage. Therefore, the temperature unevenness in the width direction of the roller 2 surface caused by the gas inside the roller 2 can be further reduced, and the reaction rate of the adhesive in the width direction of the laminated film 33 can be made approximately uniform, thereby reducing quality problems with the laminated film 33.

[0090] Preferably, during the activation process, the volume of the heat medium flowing in the main channel is maintained at 90% or more and 100% or less, more preferably 95% or more and 100% or less, relative to the total volume of the main channel. This arrangement further reduces temperature unevenness in the width direction of the roller 2 surface, thereby further reducing quality issues with the laminating film 33.

[0091] Here, the amount of gas discharged from the main passage can be adjusted by appropriately regulating the flow rate of the hot medium flowing in the hot medium flow path, the rotational speed of the roller body, and the cross-sectional area of ​​each discharge passage. That is, by discharging the gas from the main passage, the volume of the hot medium flowing in the main passage can be adjusted. If it is the roller of the manufacturing apparatus of this disclosure, the volume of the hot medium flowing in the main passage can be easily adjusted.

[0092] The activation process is preferably performed while maintaining the temperature distribution in the width direction of the surface of the roller body at 3.5°C or less (more preferably 2°C or less). This arrangement further reduces temperature unevenness in the width direction of the roller 2 surface, thereby further reducing quality issues with the laminating film 33.

[0093] In the above-described activation process, when energy rays are irradiated onto the laminating film 33 multiple times, a manufacturing apparatus equipped with two or more activation devices is typically used to perform the energy irradiation. This energy irradiation can be performed simultaneously by passing the laminating film through one roller facing two or more activation devices, or by using an apparatus with two or more rollers facing one or more activation devices, allowing the laminating film to pass through multiple rollers simultaneously.

[0094] In this embodiment, the process further includes irradiating the activated bonding film 33 with energy rays. This arrangement allows for more reliable activation of the adhesive.

[0095] In this embodiment, the process of irradiating the activated laminating film 33 with energy rays is performed on a roller with a different configuration than the roller in the activation process described above, which is different from the energy irradiation in the activation process described above.

[0096] It should be noted that the manufacturing method disclosed herein is not limited to the embodiments described above, and modifications can be made without departing from the spirit of this disclosure. For example, the manufacturing method disclosed herein is not limited to using... Figure 1 It can be achieved using the manufacturing apparatus 15, or it can be achieved using other different apparatuses.

[0097] In another embodiment of the manufacturing method of the optical laminate, a bonding process and an activation process are included. A heat medium flow path for circulating heat medium is provided inside the roller. The roller has a roller body whose centerline is aligned with the axis of rotation and whose outer peripheral surface extends in a cylindrical shape. The surface temperature of the roller is adjusted by a heat medium circulation mechanism that circulates the heat medium in the heat medium flow path. The heat medium flow path includes: a main passage that extends along the axis of rotation in a manner corresponding to the entire area of ​​the outer peripheral surface of the roller body; and a discharge passage that discharges the heat medium flowing through the main passage. That is, the discharge passage is not limited to the first discharge passage and the second discharge passage, for example, the second discharge passage may be omitted. The activation process includes the operation of circulating heat medium in the heat medium flow path while rotating the roller body. In the activation process, the volume of the heat medium flowing in the main passage is maintained at 90% or more and 100% or less of the total volume of the main passage, preferably 95% or more and 100% or less.

[0098] According to this configuration, a heat transfer medium can circulate within the roller body while the gas in the main passage is discharged through the exhaust passage. Therefore, temperature unevenness in the width direction of the roller surface caused by gas inside the roller can be reduced, and the adhesive reaction rate can be made approximately uniform in the width direction of the laminated film, thereby reducing quality issues with the laminated film.

[0099] (Roller structure)

[0100] Figure 2 This is a schematic cross-sectional view of an example of a roller-equipped device (hereinafter, this roller is sometimes referred to as "roller device 1") that can be applied in the manufacturing method of this disclosure. Figure 2 As shown, the roller device 1 is used to continuously convey the laminating film W1 ( Figure 1 A device for adjusting the temperature of the bonding film W1 by contacting the bonding film 33. The roller device 1 is included in the manufacturing apparatus 15 of the optical laminate.

[0101] The roller device 1 includes: the roller 2 described above, which has a heat medium flow path 10 through which the heat medium H1 flows and is rotatable about the rotation axis C1; and a heat medium circulation unit 3 (the heat medium circulation mechanism) which circulates the heat medium H1 in the heat medium flow path 10.

[0102] The roller 2 comprises: a roller body 4, which is formed of metal material, with the roller centerline aligned with the rotation axis C1, and the outer peripheral surface 4a extending in a cylindrical shape; a pair of shaft portions 5, which are integrally provided with each end portion 4b of the roller body 4, with the shaft centerline aligned with the rotation axis C1; and a pair of rotary joints 6, which connect each shaft portion 5 to the heat medium circulation unit 3, and each shaft portion 5 is rotatably pivotally supported on the support frame 7 via bearing B1.

[0103] The heat medium flow path 10 includes: a main passage 10a, which is formed inside the roller body 4; an inlet passage 10b, which extends in a straight line on the rotation axis C1 of a shaft 5 and communicates with the main passage 10a; and a first outlet passage 10c, which extends in a straight line on the rotation axis C1 of another shaft 5 and communicates with the main passage 10a.

[0104] The cross-section of the main passage 10a is circular, and it is shaped to extend along the axis of rotation C1 in a manner corresponding to the entire area of ​​the outer peripheral face 4a.

[0105] The cross-section of the inlet passage 10b is circular, and the cross-sectional area is set to be smaller than that of the main passage 10a. The inlet passage 10b will introduce the heat medium H1 ejected from the heat medium circulation unit 3 into the main passage 10a.

[0106] The first discharge passage 10c has a circular cross-section, and its cross-sectional area is set to be smaller than that of the main passage 10a. The first discharge passage 10c discharges the heat medium H1 of the main passage 10a to the heat medium circulation unit 3. That is, the cross-sectional area of ​​the first discharge passage 10c is smaller than the cross-sectional area of ​​the portion of the main passage 10a that extends along the rotation axis C1 in a manner corresponding to the entire area of ​​the outer peripheral surface 4a.

[0107] The heat medium circulation unit 3 circulates the heat medium H1 from one end of the roller 2 to the other end. The heat medium H1 passes through the interior of the roller 2 in the order of the inlet passage 10b, the main passage 10a and the first outlet passage 10c.

[0108] Inside the other end portion 4b of the roller body 4, a second discharge passage 10d is formed, extending in an L-shape when viewed from the front. The second discharge passage 10d is as follows: Figures 2 to 4 As shown, one end is downstream of the main passage 10a of the roller body 4 and is connected to the main passage 10a near the outer peripheral surface 4a. On the other hand, the other end is connected to the upstream side of the first discharge passage 10c. Twelve such passages are formed at equal intervals around the rotation axis C1.

[0109] The flow of the heat medium H1 inside the roller 2 when the roller device 1 is activated will be described in detail below.

[0110] First, the heat medium circulation unit 3 of the roller device 1 is activated. At this time, the heat medium H1 flows sequentially through the inlet passage 10b, the main passage 10a, and the first outlet passage 10c of the roller 2.

[0111] Then, move roller 2 to one side around the rotation axis C1 ( Figure 3 The roller 2 rotates (arrow R1) and comes into contact with the continuously transported laminating film W1. At this time, the heat medium H1 inside the roller 2 flows in the order of the inlet passage 10b, the main passage 10a, and the first outlet passage 10c. Furthermore, the heat medium H1 can circulate within the roller body 4 while the gas in the main passage 10a is discharged through the second outlet passage 10d. The heat medium H1 preferably circulates in a manner that always contacts the entire interior of the outer peripheral surface 4a of the roller body 4. If the heat medium H1 circulates in a manner that always contacts the entire interior of the outer peripheral surface 4a, the outer peripheral surface 4a of the roller body 4 is cooled without deviation, thus preventing temperature distribution deviations in the laminating film W1 in contact with the roller 2.

[0112] In addition, since there is no gas remaining in the upper part of the roller body 4, the time to cool the outer peripheral surface 4a to the desired temperature is shortened, and the laminating film W1 can be cooled efficiently.

[0113] Furthermore, since two or more second discharge passages 10d are formed at equal intervals around the rotation axis C1, each second discharge passage 10d allows the gas remaining in the upper part of the roller 2 to pass through at short intervals during the rotation of the roller 2. Therefore, the gas remaining in the upper part of the main passage 10a per revolution of the roller 2 is discharged more frequently, and the heat medium H1 can be efficiently filled into the main passage 10a without gaps.

[0114] Furthermore, since each second discharge passage 10d is formed inside the end portion 4b of the roller body 4, the overall shape of the roller 2 is smaller compared to the case where the structure with the second discharge passage 10d is installed on the outside of the roller body 4. Therefore, the entire roller 2 can be made compact, and the space around the roller 2 can be utilized effectively.

[0115] (Other structures of the roller)

[0116] Figure 5A This is a schematic cross-sectional view showing other embodiments of the rollers that can be applied to the manufacturing methods and apparatus of this disclosure. Figure 5B yes Figure 5A A cross-sectional view (AA). The roller 50 is a single tube. Figure 2 Unlike roller 2, roller 2 is a double-tube roller. The following description will only cover the parts that differ from roller 2.

[0117] like Figure 5A and Figure 5B As shown, the roller 50 has an outer tube 51, an inner tube 52, a first shaft portion 53, and a second shaft portion 54. The inner tube 52 is disposed inside the outer tube 51, and the outer tube 51 and the inner tube 52 constitute the main body of the roller. The first shaft portion 53 is provided at one end of the main body of the roller, and the second shaft portion 54 is provided at the other end of the main body of the roller.

[0118] The roller 50 has a heat medium flow path 55 through which the heat medium flows. The heat medium flow path 55 has a main passage provided in the main body of the roller (outer tube 51 and inner tube 52), an inlet passage 55d provided in the first shaft part 53, and a first outlet passage 55e provided in the second shaft part 54.

[0119] The main passage is formed by a first passage 55a, which is annular in cross-section between the outer tube 51 and the inner tube 52 when viewed from the rotation axis C1 of the roller 50; a plurality of second passages 55b extending radially from the rotation axis C1 and connected to one end of the first passage 55a; and a plurality of third passages 55c extending radially from the rotation axis C1 and connected to the other end of the first passage 55a.

[0120] The first passage 55a extends along the rotation axis C1 in such a manner that it corresponds to the entire area of ​​the outer peripheral surface 51a of the roller body. The second passage 55b and the third passage 55c are formed at equal intervals around the rotation axis C1. Each second passage 55b connects the inlet passage 55d with the first passage 55a, and each third passage 55c connects the first passage 55a with the first outlet passage 55e.

[0121] The cross-section of the first discharge passage 55e is set to be narrower than that of the first passage 55a. That is, the cross-sectional area of ​​the first discharge passage 55e is smaller than the cross-sectional area of ​​the portion of the main passage that extends along the axis of rotation C1 in a manner corresponding to the entire area of ​​the outer peripheral surface 51a.

[0122] Therefore, the heat medium, such as Figure 5A As indicated by the dashed arrow, the passage flows sequentially from the inlet passage 55d through the second passage 55b, the first passage 55a, and the third passage 55c, and exits through the first outlet passage 55e.

[0123] Around the second shaft portion 54, viewed from the direction of the rotation axis C1, multiple second discharge passages 55f extending in an approximately radial pattern are arranged at equal intervals around the rotation axis C1. Each second discharge passage 55f includes piping. The piping may be made of, for example, a rubber pipe, or may be formed of a metal pipe or a resin pipe.

[0124] One end of the second discharge passage 55f is connected to the main passage (first passage 55a) located downstream of the main passage and close to the peripheral face 51a, and the other end of the second discharge passage 55f is connected to the first discharge passage 55e.

[0125] It should be noted that the action of expelling the gas remaining in the upper part of the main passage (passage 1 55a) is related to... Figure 2 Compared to roller 2, it is the same except that the discharge path changes from the second discharge passage 10d to the second discharge passage 55f, so detailed description is omitted.

[0126] Based on the above explanation, since the second discharge passage 55f is disposed on the outside of the roller body and the second shaft 54, the processing cost is lower compared to the structure in which the second discharge passage 55f is formed inside the end of the roller body, and a roller 50 with reduced cost can be manufactured.

[0127] Example

[0128] The following describes the embodiments.

[0129] (First membrane)

[0130] A 20μm thick PVA film (average degree of polymerization of about 2400 and degree of saponification of more than 99.9 mol%) was stretched uniaxially to about 6 times using dry stretching, and then immersed in pure water at 40°C for 40 seconds while maintaining tension.

[0131] The membrane was then immersed in a dyeing aqueous solution at 28°C for 30 seconds with a mass ratio of iodine / potassium iodide / water of 0.044 / 5.7 / 100, thereby performing a dyeing treatment. The dyed membrane was then immersed in a boric acid aqueous solution at 70°C for 120 seconds with a mass ratio of potassium iodide / boric acid / water of 11.0 / 6.2 / 100, thereby performing a crosslinking treatment.

[0132] Next, the crosslinked membrane was washed with pure water at 8°C for 15 seconds, then dried at 60°C for 50 seconds under a tension of 300 N / m, and then dried at 75°C for 20 seconds. This process yielded a 7 μm thick polarized film with iodine adsorbed and oriented on the PVA membrane.

[0133] As a protective film, a cyclic olefin resin film (COP, ZF-14 manufactured by ZEON Corporation of Japan, 13 μm thick, with no UV absorption) was prepared. An aqueous adhesive was injected between the obtained polarizing film and the cyclic olefin resin film, and they were bonded together using clamping rollers. While maintaining the tension of the resulting laminate at 430 N / m, it was dried at 60°C for 2 minutes to obtain a first film having a polarizing layer and a protective layer disposed on one side of the polarizing layer. The thickness of the first film was 20 μm.

[0134] It should be noted that a water-based adhesive was prepared by adding 3 parts by weight of carboxyl-modified polyvinyl alcohol (manufactured by Kuraray Co., Ltd.; Kuraray Poval (registered trademark) KL318) and 1.5 parts by weight of water-soluble polyamide epoxy resin (manufactured by Taoka Chemical Industry Co., Ltd.; Sumirez Resin (registered trademark) 650; an aqueous solution with a solid content of 30%) to 100 parts by weight of water.

[0135] (Second membrane)

[0136] As a transparent film, a film formed from polyethylene terephthalate film with a thickness of 38 μm was prepared. An alignment layer composition was coated onto one side of the transparent film to achieve a film thickness of 3 μm, thereby achieving a cumulative light intensity of 20 mJ / cm². 2 It is irradiated with ultraviolet light in a way that forms an orientation layer.

[0137] It should be noted that the above-mentioned composition for orientation layers 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 at a ratio of 4% relative to the total mass of the resulting mixture.

[0138] A liquid crystal composition containing a polymerizable nematic liquid crystal compound (Merck, RMM28B) is applied to the formed alignment layer using a mold coating method.

[0139] In the preparation of the liquid crystal composition, a mixed heat medium was used, which consisted of methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), and cyclohexanone (CHN) with a boiling point of 155°C, in a mass ratio of 35:30:35 (MEK:MIBK:CHN). Subsequently, a liquid crystal composition was prepared such that the solid content was 1 to 1.5 g per 100 g of the liquid crystal composition, and the resulting liquid crystal composition was coated onto an alignment layer such that the coating amount before drying was 4 to 5 g.

[0140] After coating the liquid crystal composition onto the alignment layer, the resulting coating layer is dried at a drying temperature of 75°C for 120 seconds. Subsequently, the liquid crystal compound is polymerized and cured by ultraviolet (UV) irradiation. This process yields a second film consisting of a retardation layer, an alignment layer, and a transparent film. The retardation layer satisfies the relationship nz > nx = ny and is a positive C layer. The combined thickness of the retardation layer and the alignment layer is 4 μm.

[0141] (Manufacturing method of energy ray activated adhesive)

[0142] As an adhesive, the compounds are mixed in the proportions shown in Table 1 below. In Table 1, the proportions of the compounds are expressed in parts by mass.

[0143] Table 1

[0144] Number of copies Compound 1 70 Compound 2 20 Compound 3 10 Initiator 4.5 Sensitizer 2 Leveling agent 0.25 total 106.75

[0145] Details of the compounds in Table 1 are shown below.

[0146] Compound 1:

[0147] [Chemistry 1]

[0148]

[0149] 3,4-Epoxycyclohexanecarboxylic acid 3',4'-epoxycyclohexylmethyl ester (manufactured by DAICEL Chemical Industry Co., Ltd. "CEL2021P", alicyclic diester)

[0150] Compound 2:

[0151] [Chemistry 2]

[0152]

[0153] Neopentyl glycol diglycidyl ether (NPGDGE) (manufactured by Nagase ChemteX Co., Ltd., "EX-211", diepoxy)

[0154] Compound 3:

[0155] [Chemistry 3]

[0156]

[0157] 2-Ethylhexyl glycidyl ether (EHGE) (manufactured by Tokyo Chemical Industry Co., Ltd., monoepoxy)

[0158] Initiator: Cationic initiator SP-500 manufactured by ADEKA Co., Ltd. (2.25 parts solid component)

[0159] Sensitizer: DEN sensitizer manufactured by Kawasaki Chemical Industry Co., Ltd.

[0160] Leveling agent: KRM-430 leveling agent manufactured by ADEKA Co., Ltd.

[0161] (Manufacturing method of optical laminates)

[0162] use Figure 1 The manufacturing apparatus shown manufactures an optical laminate using the following steps. The rollers used in this manufacturing apparatus are configured as follows: Figure 5A The roller 50 shown is specifically designed to have a second discharge passage connected to the main passage. The diameter of the piping in the second discharge passage is 10 mm. The outermost diameter of the roller is 150 mm, and the length of the roller is 300 mm. The outer diameter (inner diameter of the outer tube) of the first passage of the main passage is 128 mm, and the inner diameter (outer diameter of the inner tube) of the first passage of the main passage is 100 mm. The cross-sectional area of ​​the first passage of the main passage is 0.0050 m². 2 .

[0163] Subsequently, while continuously transporting the first and second films, corona treatment is applied to the surfaces of the first and second films. While continuously transporting the first and second films, an energy-ray activated adhesive is applied to the corona-treated surface of the first film using a coating machine (bar coater). The first and second films are then overlapped and passed between a pair of laminating rollers to obtain a laminated film consisting of a first film / coated layer / second film.

[0164] While transporting the obtained laminated film at a speed of 10 m / min, the laminated film is subjected to a cumulative light intensity of 250 mJ / cm. 2 The adhesive is cured by irradiating it with ultraviolet light from an activation treatment device using a UVB (ultraviolet light) method while ensuring close contact with the roller body, thereby obtaining an optical laminate. The activation treatment device uses a high-pressure mercury lamp manufactured by EYE GRAPHICS.

Claims

1. A method for manufacturing an optical laminate, comprising at least one layer containing an optical film. This manufacturing method has the following characteristics: The lamination process involves bonding two dissimilar films together using an energy-ray activated adhesive to form a laminated film. In the activation process, while the laminating film is in contact with the roller, energy rays are irradiated onto the laminating film on the roller to activate the adhesive. The roller has a heat medium flow path inside, and a roller body with its center line aligned with the axis of rotation and its outer periphery extending in a cylindrical shape. The surface temperature of the roller is adjusted by a heat medium circulation mechanism that circulates the heat medium in the heat medium flow path. The heat medium flow path includes: a main passage extending along the axis of rotation in a manner corresponding to the entire area of ​​the outer peripheral surface of the roller body; an inlet passage extending along the axis of rotation and communicating with the main passage to introduce the heat medium into the main passage; a first outlet passage extending along the axis of rotation and communicating with the main passage to discharge the heat medium flowing through the main passage; and a second outlet passage, one end of which is downstream of the main passage and communicating with the main passage located near the outer peripheral surface, and the other end of which is communicating with the first outlet passage, wherein... There are two or more of the aforementioned second discharge pathways. The activation process includes the operation of circulating a heat medium within the heat medium flow path while rotating the main body of the roller.

2. A method for manufacturing an optical laminate, comprising at least one layer including an optical film, the method comprising: The lamination process involves bonding two different films together using an energy-ray activated adhesive to form a laminated film. and The activation process involves irradiating the laminating film with energy rays onto the laminating film on the roller while simultaneously bringing the laminating film into contact with the roller, thereby activating the adhesive. The roller has a heat medium flow path inside, and a roller body with its center line aligned with the axis of rotation and its outer periphery extending in a cylindrical shape. The surface temperature of the roller is adjusted by a heat medium circulation mechanism that circulates the heat medium in the heat medium flow path. The heat medium flow path includes: a main passage extending along the rotation axis in a manner corresponding to the entire area of ​​the outer peripheral surface of the roller body; and a first discharge passage extending along the rotation axis and communicating with the main passage to discharge the heat medium flowing through the main passage. A second discharge passage is provided, one end of which is downstream of the main passage and communicates with the main passage located near the outer peripheral surface, and the other end of which communicates with the first discharge passage. There are two or more such second discharge passages. The activation process includes the operation of circulating a heat medium in the heat medium flow path while rotating the main body of the roller, wherein the volume of the heat medium circulating in the main passage is maintained at more than 90% and less than 100% of the total volume of the main passage.

3. The method for manufacturing an optical laminate according to claim 1, wherein, The activation process is performed while maintaining the temperature distribution in the width direction of the surface of the roller body at 3.5°C or below.

4. The method for manufacturing an optical laminate according to claim 2, wherein, The activation process is performed while maintaining the temperature distribution in the width direction of the surface of the roller body at 3.5°C or below.

5. The method for manufacturing an optical laminate according to any one of claims 1 to 4, further comprising the step of irradiating an energy beam onto a laminating film that has undergone the activation treatment.

6. An apparatus for manufacturing an optical laminate, comprising at least one layer containing an optical film. The manufacturing apparatus includes: A bonding device that bonds two different films together using an energy-ray activated adhesive to form a bonded film; A roller that is in contact with the bonding film; and An activation treatment apparatus that activates the adhesive by irradiating the laminating film onto the roller with energy rays. The roller has a heat medium flow path inside, and a roller body with its center line aligned with the axis of rotation and its outer periphery extending in a cylindrical shape. The surface temperature of the roller is adjusted by a heat medium circulation mechanism that circulates the heat medium in the heat medium flow path. The heat medium flow path includes: a main passage extending along the rotation axis in a manner corresponding to the entire area of ​​the outer peripheral surface of the roller body; an inlet passage extending along the rotation axis and communicating with the main passage to introduce the heat medium into the main passage; and a first outlet passage extending along the rotation axis and communicating with the main passage to discharge the heat medium flowing through the main passage. The second discharge passage has one end downstream of the main passage and communicates with the main passage located near the outer peripheral surface, and the other end communicates with the first discharge passage, wherein there are two or more of the second discharge passages.

7. The manufacturing apparatus for the optical laminate according to claim 6, further comprising a control device. When the adhesive is activated using the activation treatment device, the control device controls the temperature distribution in the width direction of the surface of the roller body to be maintained below 3.5°C.

8. The apparatus for manufacturing an optical laminate according to claim 6 or 7, wherein, The main body of the roller has an outer tube and an inner tube. The space between the outer tube and the inner tube constitutes part of the heat medium flow path.

9. The apparatus for manufacturing an optical laminate according to claim 6, wherein, The second discharge passage is arranged at equal intervals around the axis of rotation.

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