JP2017058664A - Method for manufacturing laminate optical film and an apparatus for manufacturing laminate optical film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a laminate optical film capable of suppressing development of dent defects, and an apparatus for manufacturing a laminate optical film.SOLUTION: The method for manufacturing a laminate optical film 12 includes: a lamination step of laminating a second optical film 2 on one surface or both surfaces of a first optical film 4 via a curable resin to obtain a laminate 6; a first curing step of curing the curable resin; and a second curing step of further curing the curable resin after the first curing step. After the first curing step and before the second curing step, the laminate is carried without using a contact type carrying device.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for producing a laminated optical film and a production apparatus for a laminated optical film.

  Conventionally, a polarizing plate in which a protective film is laminated on one side or both sides of a polarizer is known as one of optical components constituting a liquid crystal display device or the like. As a manufacturing method of a polarizing plate, a method is known in which a polarizer and a protective film are stacked through an adhesive while being conveyed, and the adhesive is cured by irradiating active energy rays (for example, Patent Document 1). reference).

JP 2009-134190 A

  In the conventional manufacturing method, a dent-type defect may occur on the surface of the polarizing plate due to the foreign matter adhering to the transport roll. The dent-type defect is continuously generated corresponding to the cycle of the transport roll to which the foreign matter is attached, and this causes a significant decrease in the product yield as the polarizing plate. This problem similarly exists not only in polarizing plates but also in the production of laminated optical films in general.

  Then, an object of this invention is to provide the manufacturing method of the laminated optical film which can suppress generation | occurrence | production of a dent type | system | group defect, and the manufacturing apparatus of a laminated optical film.

  The present invention includes a laminating step of obtaining a laminate by superposing a second optical film on one or both sides of the first optical film via a curable resin, a first curing step of curing the curable resin, A second curing step for further curing the curable resin after the first curing step, and the laminate is contact-type after the first curing step and before the second curing step. Provided is a method for producing a laminated optical film that is transported without a transport device.

  In this manufacturing method, the curable resin starts to be cured by performing the first curing step on the laminate obtained in the lamination step, and then the curable resin is performed by performing the second curing step. Is further cured. Here, immediately after the first curing step, the curing of the curable resin is in an insufficient state, and the dent-type defect caused by the foreign matter adhering to the contact-type conveyance device that comes in contact with the laminate is the most in the laminate. It can be said that this is a prone state. Conventionally, after the first curing step, the laminate is brought into contact with the contact-type transport device and transported or turned, so that a dent-type defect has occurred. On the other hand, in the manufacturing method of the present invention, after the first curing step and before the second curing step, that is, at the stage where the dent-type defect is most likely to occur, the laminate is passed through the contact type conveying device. Carry without. Therefore, according to this invention, generation | occurrence | production of a dent type | system | group defect can be suppressed.

  In the manufacturing method of the present invention, after the first curing step and before the second curing step, a transport direction changing step of changing the transport direction of the laminated body via the non-contact type transport device is provided. It may be. If the transport direction of the laminated body can be changed, the degree of freedom in designing the transport line is increased, and space-saving design is facilitated. Further, since a non-contact type transport device is used for changing the transport direction, the state in which the laminate is not brought into contact with the contact type transport device is maintained after the first curing step and before the second curing step. .

  Here, at least one of the first curing step and the second curing step may be an active energy ray irradiation step in which the laminate is irradiated with active energy rays to cure the curable resin. And both the 1st hardening process and the 2nd hardening process may be the active energy ray irradiation process which irradiates an active energy ray to a laminated body, and hardens curable resin.

  When an active energy ray is used for curing the curable resin, the active energy ray may be an ultraviolet ray.

  In the case where active energy rays are used for curing the curable resin, the first curing step irradiates the laminate with active energy rays while adhering the laminate to the outer peripheral surface of the rotating roll. It may be an active energy ray irradiation process for curing the resin.

  The manufacturing method of the present invention has at least one additional curing step for further curing the curable resin after the second curing step, and after the second curing step and before all the additional curing steps. The laminate may be transported without using a contact-type transport device. When further curing process is carried out in order to make the curing of the curable resin more reliable, in order to more reliably suppress the occurrence of dent system defects, the laminated body is contact-type transport device until the final irradiation is finished. It is better not to touch.

  Moreover, when it has the said additional hardening process, the conveyance direction change process which changes the conveyance direction of a laminated body via a non-contact-type conveyance apparatus after a 2nd hardening process and before an additional hardening process. You may have.

  In the production method of the present invention, the first optical film may be a polarizer, and the second optical film may be a protective film. Especially when manufacturing a polarizing plate from these films as a laminated optical film, the effect of the present invention is produced suitably.

  The present invention provides a laminating means for obtaining a laminate by superposing a second optical film on one or both sides of the first optical film via a curable resin, a first curing means for curing the curable resin, And a second curing unit for further curing the curable resin of the laminate supplied from the first curing unit, and a contact-type conveying device between the first curing unit and the second curing unit. An apparatus for producing a laminated optical film is provided.

  In this manufacturing apparatus, by applying the first curing means to the laminate obtained by the lamination means, the curable resin starts to be cured, and subsequently the second curing means is applied, so that the curable resin is cured. The resin hardens further. Here, immediately after the application of the first curing means, the curable resin is in a semi-cured state, and the dent-type defect caused by the foreign matter adhering to the contact-type conveyance device that comes in contact with the laminate is the most in the laminate. It can be said that this is a prone state. Conventionally, after applying the first curing means, the laminated body is brought into contact with the contact-type conveying device to be conveyed or turned, so that a dent-type defect has occurred. On the other hand, the manufacturing apparatus of the present invention does not include a contact type conveying device between the first curing means and the second curing means, that is, in a place where the dent-type defect is most likely to occur. Therefore, according to this invention, generation | occurrence | production of a dent type | system | group defect can be suppressed.

  The manufacturing apparatus of the present invention may further include a non-contact type transport device that changes the transport direction of the laminate between the first curing means and the second curing means.

  Here, at least one of the first curing unit and the second curing unit may be an active energy ray irradiation unit that cures the curable resin by irradiating an active energy ray toward the laminate. Then, both the first curing means and the second curing means may be active energy ray irradiating means for irradiating an active energy ray toward the laminate to cure the curable resin.

  The manufacturing apparatus of the present invention includes a roll that rotates while the laminate is in close contact with the outer peripheral surface, and the first curing unit irradiates the active energy ray toward the laminate that is in close contact with the outer peripheral surface of the rotating roll. A curable resin may be cured.

  The manufacturing apparatus of the present invention further includes at least one additional curing unit that further cures the curable resin of the laminate supplied from the second curing unit, and includes the second curing unit and all the additional curing units. It is good also as an aspect which does not provide a contact-type conveyance apparatus in between.

  Here, the first optical film may be a polarizer, and the second optical film may be a protective film.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the laminated optical film which can suppress generation | occurrence | production of a dent type | system | group defect, and the manufacturing apparatus of a laminated optical film can be provided.

It is a schematic side view which shows the manufacturing apparatus of the polarizing plate of the 1st Embodiment of this invention. It is a schematic side view which shows the manufacturing apparatus of the polarizing plate of another aspect of the 1st Embodiment of this invention. It is a schematic side view which shows the manufacturing apparatus of the polarizing plate of the 2nd Embodiment of this invention. It is a schematic side view which shows the manufacturing apparatus of the polarizing plate of other embodiment of this invention.

  Hereinafter, preferred embodiments of the present invention will be described in detail.

<First Embodiment>
As the first embodiment of the present invention, an example in which a polarizer as a first optical film and a protective film as a second optical film are bonded together to produce a polarizing plate (laminated optical film) is shown. . In this production apparatus and production method, a laminate is formed by superposing a protective film on one or both sides of a polarizer formed into a film via an active energy ray-curable resin, and active energy rays are provided in a plurality of stages. The active energy ray curable resin is cured by irradiating it in steps. In this manufacturing process, the laminate is transported by a transport roll.

(Polarizer)
As a polarizer, the well-known material conventionally used for manufacture of a polarizing plate can be used. In general, a film obtained by dyeing a uniaxially stretched polyvinyl alcohol film with iodine or a dichroic dye and then treating with boric acid can be used.

  The thickness of the polarizer is preferably 0.1 to 50 μm, and more preferably 1 to 30 μm.

(Protective film)
The protective film is a film that prevents the polarizer from being cracked or damaged. Examples of the material include the following films.
Group A: Resin films with low moisture permeability such as amorphous polyolefin resin film, polyester resin film, (meth) acrylic resin film, polycarbonate resin film, polysulfone resin film, alicyclic polyimide resin film, etc. Can be mentioned. Examples of the amorphous polyolefin-based resin film include “Topas” manufactured by Ticona of Germany, “Arton” manufactured by JSR Co., Ltd., and “ZEONOR” manufactured by Nippon Zeon Co., Ltd. And “ZEONEX”, “Appel” manufactured by Mitsui Chemicals, Inc., and the like.
Group B: In addition to those listed in Group A, cellulose acetate type resin films such as a triacetyl cellulose film and a diacetyl cellulose film may be mentioned. Examples of the triacetyl cellulose film include “Fujitack TD80”, “Fujitack TD80UF” and “Fujitack TD80UZ” manufactured by Fuji Photo Film Co., Ltd., “KC8UX2M” and “KC8UY” manufactured by Konica Corporation. .

  The kind of protective film laminated | stacked on both surfaces of a polarizer may mutually be the same, or may differ. When laminating different films, it is preferable to select one from each of the A group and the B group.

  Prior to bonding to the polarizer, the protective film may be subjected to easy adhesion treatment such as saponification treatment, corona treatment, primer treatment, and anchor coating treatment on the bonding surface. Moreover, you may have various process layers, such as a hard-coat layer, an antireflection layer, an anti-glare layer, in the surface on the opposite side to the bonding surface to the polarizer of a protective film.

  The protective film may be a simple protective film having no optical function, or may be a protective film having an optical function such as a retardation film or a brightness enhancement film.

  The thickness of the protective film is preferably 5 to 200 μm, more preferably 5 to 120 μm, and still more preferably 5 to 85 μm.

(Active energy ray curable resin)
The polarizer and the protective film are bonded via an active energy ray curable resin. As the active energy ray-curable resin, an adhesive or a pressure-sensitive adhesive can be used.

  The adhesive refers to an adhesive that fixes two films (here, a polarizer and a protective film) that are not scheduled to be peeled off after bonding. As the adhesive, various adhesives conventionally used in the production of polarizing plates can be used. From the viewpoints of weather resistance, refractive index, cationic polymerizability, etc., an epoxy resin containing no aromatic ring in the molecule is preferred.

  As an epoxy resin, a hydrogenated epoxy resin, an alicyclic epoxy resin, an aliphatic epoxy resin, etc. are preferable, for example. For epoxy resins, polymerization initiators (for example, photocationic polymerization initiators for polymerization by UV irradiation, thermal cationic polymerization initiators for polymerization by heat ray irradiation), and other additives (sensitizers, etc.) Can be added to prepare an epoxy resin composition for coating.

  As the adhesive, acrylic resins such as acrylamide, acrylate, urethane acrylate, and epoxy acrylate can be used.

  It is preferable that the thickness before hardening of the adhesive bond layer after bonding a polarizer and a protective film using the bonding roll mentioned later is 0.01-5 micrometers.

  The pressure-sensitive adhesive means one that fixes two films that are to be peeled off after adhesion. The pressure-sensitive adhesive is preferably a composition in which an acrylic resin, a styrene resin, a silicone resin, or the like is usually used as a base polymer, and a crosslinking agent such as an isocyanate compound, an epoxy compound, or an aziridine compound is added thereto. Furthermore, it can also be set as the adhesive which contains microparticles | fine-particles and shows light-scattering property.

  The pressure-sensitive adhesive is preferably formed to be thin as long as the processability and durability characteristics are not impaired, and the thickness after bonding the polarizer and the protective film is preferably 1 to 40 μm, and 3 to 25 μm. It is more preferable that When the thickness of the pressure-sensitive adhesive is 3 to 25 μm, it has particularly good processability and is suitable for suppressing the dimensional change of the polarizer.

  As a method of laminating the pressure-sensitive adhesive on the polarizer or the protective film, for example, a method of applying a solution containing each component including the base polymer to the polarizer or the protective film may be used. After forming the pressure-sensitive adhesive layer, it may be transferred to a polarizer or a protective film and laminated.

  Both the adhesive and the pressure-sensitive adhesive are cured by active energy rays (ultraviolet rays or heat rays).

(Polarizer)
The polarizing plate is bonded to one side or both sides of a display cell (image display element) such as a liquid crystal cell. The polarizing plate can further include another optical layer laminated on the protective film. As another optical layer, a reflective polarizing film that transmits a certain kind of polarized light and reflects polarized light having the opposite properties; a film with an antiglare function having an uneven surface; a film with a surface antireflection function; surface A reflective film having a reflective function; a transflective film having both a reflective function and a transmissive function; and a viewing angle compensation film.

  The thickness of the polarizing plate is preferably 20 to 500 μm, and more preferably 20 to 200 μm.

(manufacturing device)
Hereinafter, a polarizing plate manufacturing apparatus and manufacturing method will be described with reference to the drawings. Here, the case where a protective film is laminated | stacked on both surfaces of a polarizer and active energy ray curable resin is an adhesive agent is demonstrated. In addition, in each figure, the same code | symbol is attached | subjected to the same part or an equivalent part, and the overlapping description is abbreviate | omitted.

  The polarizing plate manufacturing apparatus 1 shown in FIG. 1 includes an adhesive coating apparatus 3 (3A, 3B) for applying an adhesive to one surface of a protective film 2 (2A, 2B), a polarizer 4 and a protective film. A laminating roll (laminating means) 5 for laminating the films 2A and 2B to each other, a roll 7 for adhering the laminated body 6 on which the polarizer 4 and the protective films 2A and 2B are laminated, and the outer periphery of the roll 7 First active energy ray irradiation device (first curing means, first active energy ray irradiation means) 8 installed at a position facing the surface, and a non-contact type for changing the transport direction of the laminate 6 A transport device 9, a second active energy ray irradiation device (second curing means, second active energy ray irradiation means) 10 installed further downstream in the transport direction, and a transport nip roll 11 are laminated. In order along the transport direction of the body 6 It has been kicked.

  As a manufacturing method of a polarizing plate using this manufacturing apparatus 1, first, the protective film 2A, 2B that is continuously drawn out from a rolled state is applied to one side with an adhesive coating apparatus 3A, 3B. An adhesive is applied to (adhesive application step). And the protective film 2A, 2B is each overlap | superposed via the adhesive agent with the bonding roll 5 on both surfaces of the polarizer 4 extended | stretched continuously from the state wound by roll shape, and the laminated body 6 is formed ( Pasting step). The above is the lamination process.

  And it conveys, making the laminated body 6 closely_contact | adhere to the outer peripheral surface of the rotating roll 7, At this time, it goes toward the laminated body 6 closely_contact | adhered to the outer peripheral surface of the roll 7 from the 1st active energy ray irradiation apparatus 8. To start curing of the adhesive (first curing step, hereinafter referred to as “first active energy ray irradiation step” because the active energy rays are irradiated).

  Next, the conveyance direction of the laminated body 6 where the curing of the adhesive has started is changed via the non-contact type conveyance device 9 (conveyance direction changing step). Then, the active energy ray is irradiated from the second active energy ray irradiation device 10 toward the laminated body 6 to further cure the adhesive (second curing step. Also referred to as “active energy ray irradiation step 2”). Finally, the laminate 6 passes through the conveying nip roll 11 and is wound up as a polarizing plate 12 around a winding roll 13.

  The polarizing plate 12 is manufactured through the above steps. Details of each step will be described below.

  In the production method described above, the method for applying the adhesive to the protective films 2A and 2B is not particularly limited, and various coating methods such as a doctor blade, a wire bar, a die coater, a comma coater, and a gravure coater can be used. . Among these, taking into consideration the thin film coating, the degree of freedom of the pass line, the wideness, etc., gravure rolls are preferable as the adhesive coating apparatuses 3A and 3B.

The roll 7 constitutes a convex curved surface whose outer peripheral surface is mirror-finished. The roll 6 is conveyed while the laminate 6 is in close contact with the surface, and the adhesive is cured by the first active energy ray irradiation device 8 in the process. . The diameter of the roll 7 is not particularly limited for curing the adhesive and sufficiently adhering the laminated body 6, but the active energy rays are applied while the laminated body 6 with the adhesive layer being uncured passes through the roll 7. It is preferable to irradiate at an integrated light quantity of ultraviolet rays at 30 mJ / cm ² or more. The roll 7 is rotationally driven at a rotational speed corresponding to the line speed.

  The roll 7 may act as a cooling roll in order to make it difficult for heat to be applied to the laminate 6 when the adhesive is cured by irradiation with active energy rays. In this case, the surface temperature of the cooling roll is preferably 20 to 25 ° C.

The light source of the active energy ray in the first active energy ray irradiation step is not particularly limited, but ultraviolet light having a light emission distribution at a wavelength of 400 nm or less, for example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a chemical lamp, black A light lamp, a microwave excitation mercury lamp, a metal halide lamp, etc. can be used. The light irradiation intensity to the epoxy resin composition is such that the irradiation intensity in the wavelength region effective for activating the polymerization initiator contained in the epoxy resin composition is 0.1 to 100 mW / cm from the viewpoint of reaction time and heat generation. ² is preferable.

  The irradiation of the active energy ray in the first active energy ray irradiating step is preferably performed a plurality of times for the purpose of increasing the integrated light amount. The manufacturing apparatus 1 of the present embodiment has two first active energy ray irradiation devices 8 and performs irradiation of active energy rays twice.

In the 1st active energy ray irradiation process, from the viewpoint of suppressing the wavy unevenness in the polarizing plate 12 and the viewpoint of suppressing the curing shrinkage in the 2nd active energy ray irradiation process, the ultraviolet rays while passing through the roll 7 ( The active energy ray is irradiated so that the cumulative amount of UVB) is preferably 10 to 185 mJ / cm ² , more preferably 60 to 175 mJ / cm ² .

The line speed of the laminate 6 is not particularly limited, and is a condition in which the longitudinal direction (conveying direction) is under a tension of 75 to 1150 N / m, at least the irradiation intensity is 30 mW / cm ² or more, and the irradiation time is 0.3 seconds or more. Below, it is preferable to irradiate the laminated body 6 with an active energy ray.

  The non-contact type conveying device 9 in the conveying direction changing step can change the conveying direction of the laminated body 6 without contacting the laminated body 6 and is equal to or larger than the width of the laminated body 6 in the same manner as a normal conveying roll. Have a width of The non-contact type conveyance device 9 has a curved surface whose surface is curved along the conveyance direction of the laminate 6, and a large number of holes are opened on the surface. And it has the structure which air blows off through the hole from the inside.

  The laminated body 6 is prevented from receiving air blown out from the inside of the non-contact type transport device 9 and being lifted from the surface of the non-contact type transport device 9 and coming into contact with the non-contact type transport device 9, and the transport direction thereof is an acute angle. Or converted at an obtuse angle. Examples of the non-contact type conveyance device 9 having such a configuration include “air turn bar” manufactured by BELLMATIC Corporation. The direction change angle is appropriately determined depending on the layout of the transport line, and is usually 10 ° to 180 °. Although only one non-contact type transport device 9 is illustrated in FIG. 1, a plurality of non-contact type transport devices 9 may be provided for the convenience of the layout of the transport line.

  In the manufacturing apparatus 1, there is no contact-type transfer device such as a roll that contacts the stacked body 6 in the transfer section between the first active energy ray irradiation device 8 and the second active energy ray irradiation device 10. Here, examples of the contact-type transport device include a device that contacts the stacked body 6 during transmission and transmits power for transport, and a device that only has a role of supporting the stacked body 6 being transported. Usually, there are guide rolls, nip rolls, etc. that transmit power for conveyance, and there are guide bars, free rolls, etc., that have only the role of supporting the laminate 6.

  The 2nd active energy ray irradiation process is provided in order to supplement the integrated light quantity of the active energy ray by the 1st active energy ray irradiation apparatus 8. FIG. A second active energy ray irradiating device 10 is provided on the downstream side of the non-contact type conveying device 9 in the conveying direction, and additional active energy rays are irradiated toward the laminate 6 supplied from the first active energy ray irradiating step. Further curing of the adhesive. The manufacturing apparatus 1 of this embodiment has three second active energy ray irradiation devices 10 and performs irradiation of active energy rays three times.

  The light source of the second active energy ray irradiation device 10 may be the same as or different from the light source of the first active energy ray irradiation device 8.

Light irradiation intensity in the second active energy ray irradiation process, the accumulated light quantity of ultraviolet (UVB) in the entire process, in conjunction with the first active energy ray irradiation process is 10 mJ / cm ² or more, and particularly 60~5000mJ / cm ² It is preferable to set so as to be.

  The rate at which the adhesive is cured through all the active energy ray irradiation steps, that is, the reaction rate, is preferably 90% or more, and more preferably 95% or more.

(Function and effect)
In the manufacturing method of the polarizing plate using the manufacturing apparatus 1 demonstrated above, by irradiating the 1st active energy ray in the 1st active energy ray irradiation process with respect to the laminated body 6 obtained at the lamination process, The adhesive starts to harden, and then the second active energy ray is irradiated in the second active energy ray irradiating step, whereby the adhesive is further hardened.

  Here, immediately after the first active energy ray irradiation step, the adhesive is not sufficiently cured, and a dent-type defect caused by a foreign matter adhering to the contact-type conveyance device that comes into contact therewith is a laminate. 6 is the most likely state. Conventionally, after the first active energy ray irradiation step, the laminated body 6 is brought into contact with a contact type conveying device such as a roll to be conveyed or changed in direction, so that a dent type defect has occurred. In contrast, in the manufacturing method using the manufacturing apparatus 1, after the first active energy ray irradiation step and before the second active energy ray irradiation step, that is, at the stage where the dent-type defect is most likely to occur, The laminated body 6 is conveyed without going through a contact-type conveying device. Therefore, according to this embodiment, generation | occurrence | production of a dent type | system | group defect can be suppressed.

  Moreover, in this manufacturing method, after the first active energy ray irradiation step and before the second active energy ray irradiation step, the transfer direction of the stacked body 6 is changed via the non-contact type transfer device 9. Since it has the conveyance direction change process, the conveyance direction of the laminated body 6 can be changed. Thereby, the freedom degree of design of a conveyance line increases and it becomes easy to make a space-saving design. In addition, since the non-contact type transport device 9 is used for changing the transport direction, the laminated body 6 is contact-type transport after the first active energy ray irradiation step and before the second active energy ray irradiation step. The state of not touching the device is maintained.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment. For example, although the aspect provided with the non-contact type conveying apparatus 9 as the manufacturing apparatus 1 was shown in the said embodiment, as shown in FIG. 2, it is good also as an aspect which does not include the non-contact type conveying apparatus 9 as 1 A of manufacturing apparatuses. . In this case, in the section from the first active energy ray irradiation step to the second active energy ray irradiation step, the stacked body 6 is conveyed without changing the direction.

  In the above embodiment, the cross-sectional shape of the non-contact type conveyance device 9 is circular as shown in FIG. 1, but the cross-sectional shape is not necessarily closed, and the non-contact type conveyance device 9 has a plate shape that provides a curved surface. May be. Further, the non-contact type conveyance device 9 does not necessarily have a curved surface, and may be a flat surface. In this case, the stacked body 6 is transported without changing its direction.

  In the above embodiment, the active energy ray is an ultraviolet ray, but the active energy ray may be a heat ray. In this case, a thermal cationic polymerization initiator can be used as the polymerization initiator, infrared rays or the like can be used as the heat rays, and the amount of energy to be given to the laminate 6 is the same as in the case of the ultraviolet rays.

  Moreover, although the aspect of the 3 sheet bonding which bonds the protective film 2 on both surfaces of the polarizer 4 was shown in the said embodiment, the aspect of the 2 sheet bonding which bonds the protective film 2 only on the single side | surface of the polarizer 4 is shown. It is good.

  Moreover, in the said embodiment, the aspect which has a 1st active energy ray irradiation process (1st active energy ray irradiation apparatus 8) and a 2nd active energy ray irradiation process (2nd active energy ray irradiation apparatus 10). As shown, on the downstream side in the transport direction of the second active energy ray irradiation step, a third active energy ray irradiation step (third active energy ray irradiation device) and a fourth active energy ray irradiation step (fourth) The active energy ray irradiation apparatus) may have an additional irradiation step (additional irradiation means). In this case, after the second active energy ray irradiation step and before all the additional irradiation steps, it is preferable to transfer the stacked body 6 without using a contact-type transfer device.

<Second Embodiment>
Hereinafter, a second embodiment of the present invention will be described. The second embodiment is different from the first embodiment in that a water-based curable resin is used instead of the active energy ray curable resin as the curable resin, and the laminate is irradiated with active energy rays in the curing step. Instead of passing through a drying oven.

  As 2nd Embodiment, the polarizer as a 1st optical film and the protective film as a 2nd optical film are bonded together, and the example which manufactures a polarizing plate (laminated optical film) is shown. In this production apparatus and production method, a laminate is formed by superposing a protective film on one or both sides of a polarizer formed into a film via an aqueous curable resin, and this is divided into a plurality of stages in a drying furnace. And dry to cure the water-based curable resin. In this manufacturing process, the laminate is transported by a transport roll.

  Hereinafter, differences from the first embodiment will be described.

(Water-based curable resin)
The water-based curable resin is a water-based adhesive, that is, an adhesive in which an adhesive component is dissolved in water or dispersed in water. As the water-based curable resin, one that is cured by heat is used.

  As the water-based curable resin, for example, a polyvinyl alcohol-based resin, a urethane resin or the like is used as a main component, and a composition containing an isocyanate-based compound, an epoxy compound, or the like can be used in order to improve adhesiveness.

  When polyvinyl alcohol resin is used as the main component of the water-based curable resin, in addition to partially saponified polyvinyl alcohol and fully saponified polyvinyl alcohol, carboxyl group-modified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, methylol group-modified polyvinyl alcohol, amino A modified polyvinyl alcohol resin such as group-modified polyvinyl alcohol may be used. When such a polyvinyl alcohol resin is used, an aqueous solution of the polyvinyl alcohol resin is used as the water-based curable resin. The density | concentration of the polyvinyl alcohol-type resin in water-system curable resin is 1-10 weight part normally with respect to 100 weight part of water, Preferably it is 1-5 weight part.

  The thickness of the adhesive layer after drying is usually about 0.001 to 5 μm, preferably 0.01 μm or more, preferably 2 μm or less, more preferably 1 μm or less. If the thickness of the adhesive layer becomes too large, the appearance of the polarizing plate tends to be poor.

  The water-based curable resin can contain a thermosetting agent.

(manufacturing device)
The polarizing plate manufacturing apparatus 100 according to the second embodiment includes a roll 7 and a first active energy ray irradiation apparatus 8 in the polarizing plate manufacturing apparatus 1 according to the first embodiment, as shown in FIG. 3. Instead of the second active energy ray irradiation device 10, a first drying furnace (first curing means) 108 and a second drying furnace (second curing means) 110 are provided.

  The laminated body 6 formed by superposing the polarizer 4 and the protective films 2A and 2B through a water-based curable resin (adhesive) is introduced into the first drying furnace 108 while being transported (the first drying furnace 108). Curing step). The laminated body 6 led out from the first drying furnace 108 is subsequently introduced into the second drying furnace 110 (second curing step). The laminated body 6 led out from the second drying furnace 110 is finally wound around the winding roll 13 as the polarizing plate 12.

  The drying method of the first drying furnace 108 is not particularly limited, and examples thereof include a hot air drying furnace, an infrared drying furnace, a combined hot air and infrared drying furnace, and the like.

  The total length of the conveyance path of the laminated body 6 in the first drying furnace 108 is 10 to 60 m, preferably 20 to 50 m. The drying temperature in the first drying furnace 108 is usually 30 ° C. to 100 ° C., more preferably 60 ° C. to 100 ° C., from the viewpoint of removing water from the water-based curable resin and making it difficult to curl. It is.

  The drying time, that is, the time from when the laminated body 6 is introduced into the first drying furnace 108 to when the laminated body 6 passes through the first drying furnace 108 is usually 50 to 1200 seconds. The time is preferably 60 to 1000 seconds, more preferably 100 to 600 seconds. If the drying time is too short, the polarizer 4 and the protective films 2A and 2B tend to be peeled off due to insufficient drying, and if it exceeds 1200 seconds, it is not preferable from the viewpoint of productivity. The drying temperature can be appropriately adjusted according to the type of the water-based curable resin.

  A guide roll may be installed in the first drying furnace 108 in order to control the transport path of the stacked body 6. A pinch roll may be installed along the conveyance path of the laminated body 6. These guide rolls and pinch rolls are both driven rollers and are driven according to the movement of the laminated body 6 conveyed by driving of a take-up roller (not shown) that winds up the laminated body 6. .

  On the other hand, a guide roll and a pinch roll need not be installed in the first drying furnace 108. In this case, it is possible to prevent a dent-type defect caused by these rolls from occurring in the laminate 6. In this case, since it is difficult to transport the stacked body 6 in the horizontal direction due to the influence of gravity, it is preferable to transport the stacked body 6 downward in the vertical direction as shown in FIG.

  In the manufacturing apparatus 100, there is no contact-type transfer device such as a roll that contacts the stacked body 6 in the transfer section between the first drying furnace 108 and the second drying furnace 110.

  The drying method, total length, drying temperature, drying time, etc. of the second drying furnace 110 are the same as those in the first drying furnace 108.

(Function and effect)
In the manufacturing method of a polarizing plate using the manufacturing apparatus 100 described above, the adhesive 6 starts to be cured by drying the laminate 6 in the first curing step, and then the laminate 6 in the second curing step. By further drying, the adhesive is further cured.

  Here, immediately after the first curing step, the adhesive is not sufficiently cured, and the dent-type defect caused by the foreign matter adhering to the contact-type conveying device that comes in contact with the laminate 6 is the most. It can be said that this is a prone state. Conventionally, after the first curing step, the laminated body 6 is brought into contact with a contact-type conveyance device such as a roll to convey or change the direction, so that a dent-type defect has occurred. On the other hand, in the manufacturing method using the manufacturing apparatus 100, the laminated body 6 is contact-type after the first curing process and before the second curing process, that is, at the stage where the dent-type defect is most likely to occur. Transport without going through the transport device. Therefore, according to this embodiment, generation | occurrence | production of a dent type | system | group defect can be suppressed.

  The same change as that of the first embodiment can be made to the second embodiment. For example, in the said embodiment, although the aspect of 3 sheet bonding which bonds the protective film 2 to both surfaces of the polarizer 4 was shown, the aspect of 2 sheet bonding which bonds the protective film 2 only to the single side | surface of the polarizer 4 is shown. It is good.

  Moreover, although the said 2nd Embodiment showed the aspect which has a 1st hardening process (1st drying furnace 108) and a 2nd hardening process (2nd drying furnace 110), the 2nd hardening process Further, in the downstream side in the transport direction, there is an additional curing step (additional curing means) as in the third curing step (third drying furnace) and the fourth curing step (fourth drying furnace). Also good. In this case, after the second curing step and before all the additional curing steps, it is preferable to transport the laminate 6 without using a contact-type transport device.

  Although the preferred embodiment of the present invention has been described above, the embodiment of the present invention is not limited to the above embodiment.

  For example, as in the manufacturing apparatus 200 shown in FIG. 4, the first active energy ray irradiation device 8 in the first embodiment is employed as the first curing means, and the second curing means is the second. You may employ | adopt the 2nd drying furnace 110 in embodiment. In this case, it is preferable to employ the active energy ray-curable resin in the first embodiment as the curable resin. Furthermore, considering the heat curing in the second curing step, the active energy ray-curable resin can contain a thermosetting agent.

  Moreover, although the example which bonds the protective film 2 to the polarizer 4 as a 2nd optical film was shown in the said embodiment, another film may be sufficient as a 2nd optical film. For example, a polarizing plate may be formed by bonding a film such as a retardation film or a viewing angle compensation film to the polarizer 4.

  Moreover, although the laminated optical film showed the example which is a polarizing plate in said two embodiment, another film may be sufficient as a laminated optical film. That is, although the 1st optical film showed the aspect which is the polarizer 4 in the said embodiment, another film may be sufficient as a 1st optical film. For example, the laminated optical film may be configured by bonding the protective film 2 or the like to a film such as a retardation film or a transparent conductive film.

  DESCRIPTION OF SYMBOLS 1,1A, 100,200 ... Manufacturing apparatus of a polarizing plate (Laminated optical film manufacturing apparatus), 2 (2A, 2B) ... Protective film (2nd optical film), 4 ... Polarizer (1st optical film) DESCRIPTION OF SYMBOLS 5 ... Bonding roll (laminating means), 6 ... Laminated body, 7 ... Roll, 8 ... 1st active energy ray irradiation apparatus (1st hardening means, 1st active energy ray irradiation means), 9 ... Non Contact-type transfer device, 10 ... second active energy ray irradiation device (second curing means, second active energy ray irradiation means), 12 ... polarizing plate (laminated optical film), 108 ... first drying furnace ( (First curing means), 110... Second drying furnace (second curing means).

Claims (16)

A laminating step of superposing a second optical film on one or both sides of the first optical film via a curable resin to obtain a laminate;
A first curing step for curing the curable resin;
A second curing step for further curing the curable resin after the first curing step;
The manufacturing method of the laminated optical film which conveys the said laminated body through a contact type conveying apparatus after the said 1st hardening process and before the said 2nd hardening process.   The method according to claim 1, further comprising a transport direction changing step of changing the transport direction of the laminate through a non-contact transport device after the first curing step and before the second curing step. A method for producing a laminated optical film.   The at least one of the first curing step and the second curing step is an active energy ray irradiation step of irradiating the laminated body with an active energy ray to cure the curable resin. 2. A method for producing a laminated optical film according to 2.   3. The active energy ray irradiation step in which each of the first curing step and the second curing step is an active energy ray irradiation step in which the laminated body is irradiated with an active energy ray to cure the curable resin. A method for producing a laminated optical film.   The method for producing a laminated optical film according to claim 3 or 4, wherein the active energy rays are ultraviolet rays.   The first curing step is an active energy ray irradiation step of irradiating the laminate with the active energy rays while the laminate is in close contact with an outer peripheral surface of a rotating roll to cure the curable resin. Item 6. The method for producing a laminated optical film according to any one of Items 3 to 5. After the second curing step, having at least one additional curing step of further curing the curable resin;
The laminated optics according to any one of claims 1 to 6, wherein the laminated body is conveyed without a contact-type conveying device after the second curing step and before all the additional curing steps. A method for producing a film.   The laminated optical system according to claim 7, further comprising a conveyance direction changing step of changing a conveyance direction of the laminated body via a non-contact type conveyance device after the second curing step and before the additional curing step. A method for producing a film. The first optical film is a polarizer;
The method for producing a laminated optical film according to any one of claims 1 to 8, wherein the second optical film is a protective film. Laminating means for obtaining a laminate by superimposing the second optical film on one side or both sides of the first optical film via a curable resin;
First curing means for curing the curable resin;
Second curing means for further curing the curable resin of the laminate supplied from the first curing means,
An apparatus for manufacturing a laminated optical film, which does not include a contact type conveying device between the first curing unit and the second curing unit.   11. The laminated optical film manufacturing apparatus according to claim 10, further comprising a non-contact type conveyance device that changes a conveyance direction of the laminated body between the first curing unit and the second curing unit.   The at least one of the first curing unit and the second curing unit is an active energy ray irradiating unit that irradiates an active energy ray toward the laminated body to cure the curable resin. The manufacturing apparatus of the laminated optical film of 10 or 11.   13. The active energy ray irradiating means for irradiating the curable resin by irradiating active energy rays toward the laminated body, both of the first curing means and the second curing means. Manufacturing equipment for laminated optical films. A roll that rotates while the laminate is in close contact with the outer peripheral surface;
The said 1st hardening means irradiates the said active energy ray toward the said laminated body closely_contact | adhered to the said outer peripheral surface of the said roll to rotate, The said curable resin is hardened | cured. Manufacturing equipment for laminated optical films. Comprising at least one additional curing means for further curing the curable resin of the laminate supplied from the second curing means;
The apparatus for producing a laminated optical film according to any one of claims 10 to 14, wherein a contact-type transport device is not provided between the second curing unit and all the additional curing units. The first optical film is a polarizer;
The laminated optical film manufacturing apparatus according to any one of claims 10 to 15, wherein the second optical film is a protective film.

Images