JP2019028285A - Production apparatus and production method of optical film - Google Patents

Abstract

To provide a production apparatus and a production method of an optical film by which an optical film having good qualities can be produced.SOLUTION: A production apparatus 1 of an optical film carries out a moisture conditioning treatment for adjusting a water content percentage of a raw material film 5 while conveying the raw material film 5. The production apparatus 1 of an optical film has: a moisture conditioning furnace 3 for the moisture conditioning treatment, which has at least one conveyance opening 30 having an opening 31 for conveying the raw material film 5 into or out of the furnace; and a dew condensation suppressing device for suppressing dew condensation on an outer wall surface of the conveyance opening 30. The dew condensation suppressing device is installed on at least one conveyance opening 30.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an optical film manufacturing apparatus and manufacturing method.

  Various optical films such as polarizing plates and retardation plates are used in image display devices (liquid crystal display devices, organic EL display devices, etc.). The optical film is usually manufactured by performing various treatments while continuously unwinding and transporting a long raw material film. As one of the treatments applied to the raw material film, a humidity conditioning treatment for performing a humidification treatment or the like on the raw material film is known (for example, Patent Document 1).

JP, 2006-224423, A

  [Technical Field] The present invention relates to an optical film manufacturing apparatus and manufacturing method for manufacturing an optical film by performing humidity conditioning, and an optical film manufacturing apparatus and manufacturing method capable of manufacturing an optical film having good quality. The purpose is to provide.

The present invention provides an optical film manufacturing apparatus and manufacturing method described below.
[1] An optical film manufacturing apparatus that performs humidity conditioning for adjusting the moisture content of the raw material film while conveying the raw material film,
A humidity control furnace for carrying out the humidity control process, having one or more openings for conveyance having an opening for carrying in or carrying out the raw material film;
A dew condensation suppressing device for suppressing dew condensation on the outer wall surface of the opening for conveyance;
The said dew condensation suppression apparatus is an optical film manufacturing apparatus installed in at least one of the said opening parts for conveyance.

  [2] The optical film manufacturing apparatus according to [1], wherein the humidity control furnace is a humidification furnace that performs a humidification process for humidifying the raw material film.

[3] The dew condensation suppressing device is
A suction device for sucking the humidity control gas in the humidity control furnace flowing out of the opening of the transfer opening;
An air supply device for supplying air in a curtain shape to the opening of the transfer opening; and
The apparatus for producing an optical film according to [1] or [2], which is at least one of a heating device for heating the outer wall surface of the opening for conveyance.

[4] The dew condensation suppressing device is the suction device,
The suction device is installed along the opening at least on the upper side of the film surface of the raw material film that is outside the humidity control furnace and passes through the opening of the opening for transporting [1] The manufacturing apparatus of the optical film in any one of-[3].

[5] The dew condensation suppressing device is the suction device,
The suction device is an optical film manufacturing apparatus according to [3] or [4], which is a suction box.

  [6] The dew condensation suppression device is the suction device, and the suction device further includes a heating unit for heating the sucked humidity-control gas, according to any one of [3] to [5]. Optical film manufacturing equipment.

[7] The dew condensation suppressing device is the air supply device,
The apparatus for producing an optical film according to [3], wherein the temperature of the air supplied by the air supply device is higher than a dew point temperature of the humidity control gas.

[8] A method for producing an optical film that performs humidity conditioning for adjusting the moisture content of the raw material film while conveying the raw material film,
The humidity control treatment is performed in a humidity control furnace having at least one opening for transporting with an opening for carrying in or carrying out the raw material film,
A method for producing an optical film, comprising: performing dew condensation suppression processing that suppresses dew condensation on an outer wall surface of the conveyance opening in at least one of the conveyance openings.

[9] The method for producing an optical film according to [8], wherein the humidity adjustment treatment is a humidification treatment.
[10] The dew condensation suppressing process
A suction process for sucking humidity-controlled gas in the humidity-control furnace flowing out of the opening of the transfer opening;
An air supply process for supplying air in a curtain shape to the transfer opening; and
The method for producing an optical film according to [8] or [9], wherein the method is at least one of heating processes for heating the outer wall surface of the opening for conveyance.

[11] The dew condensation suppressing process is at least one of the suction process and the heating process.
The thickness of the said raw material film is a manufacturing method of the optical film as described in [10] or [11] which is 1 micrometer or more and 200 micrometers or less.

[12] The dew condensation suppressing process is the suction process.
In the suction process, the humidity-controlled gas is sucked out at least above the film surface of the raw material film that is outside the humidity control furnace and passes through the opening of the opening for transporting. 11] The manufacturing method of the optical film of description.

[13] The dew condensation suppressing process is the suction process.
Furthermore, the manufacturing method of the optical film in any one of [10]-[12] which performs the heat processing which heats the suck | inhaled said humidity control gas.

[14] The dew condensation suppressing process is the air supply process.
The method for producing an optical film according to [10], wherein the temperature of the air supplied in the air supply process is higher than a dew point temperature of the humidity control gas in the humidity control furnace.

  [15] The optical film is one of a polarizing film, a protective film bonded to the polarizing film, and a polarizing plate in which the protective film is bonded to one surface or both surfaces of the polarizing film. [8] The manufacturing method of the optical film in any one of [14].

  According to the present invention, an optical film having good quality can be produced even if a humidity control process is performed while conveying a raw material film.

It is a side view which represents typically an example of humidity control furnace vicinity of the manufacturing apparatus of the optical film of this invention.

The apparatus for producing an optical film of the present invention performs humidity conditioning for adjusting the moisture content of the raw material film while conveying the raw material film,
A humidity control furnace for carrying out a humidity control process, having one or more openings for conveyance provided with openings for carrying in or carrying out a raw material film;
A dew condensation suppressing device for suppressing dew condensation on the outer wall surface of the transport opening;
The dew condensation suppression device is installed in at least one of the openings for conveyance.

Moreover, the manufacturing method of the optical film of the present invention is to perform humidity conditioning treatment for adjusting the moisture content of the raw material film while conveying the raw material film,
The humidity control treatment is performed in a humidity control furnace having one or more opening portions for conveyance having an opening for carrying in or carrying out the raw material film,
In at least one of the transfer openings, a dew condensation suppressing process is performed to suppress condensation on the outer wall surface of the transfer opening.

  The humidity control treatment for adjusting the moisture content of the raw material film refers to a treatment for adjusting the content of water contained in the raw material film. Moreover, a raw material film means the film before performing a humidity control process at least, and an optical film means the film manufactured by performing a humidity control process with respect to a raw material film at least. The optical film may be obtained by subjecting the raw material film to a treatment other than the humidity conditioning treatment. In the following, the raw material film before the humidity conditioning treatment is referred to as a raw material film before the humidity conditioning, and the raw material film after the humidity conditioning treatment may be referred to as the raw material film after the humidity conditioning.

  Since the humidity control process performed in the humidity control furnace is to adjust the moisture content of the raw material film, the humidity control furnace is filled with a humidity control gas having a temperature and humidity corresponding to the humidity control processing conditions. . The humidity control gas can contain water vapor in order to adjust the water content of the raw material film. When the water vapor contained in the humidity control gas is condensed by cooling or the like when flowing out of the humidity control furnace, the outer wall surface of the transport opening of the humidity control furnace may condense. Condensed water generated by this dew condensation may adhere to the raw material film passing through the opening of the conveyance opening and may contaminate the raw material film.

  In the optical film manufacturing apparatus and the optical film manufacturing method, the water vapor contained in the humidity control gas flowing out of the humidity control furnace is condensed by providing a dew condensation suppression device in at least one of the openings for conveyance. It is possible to suppress dew condensation on the outer wall surface of the transfer opening. Thereby, it can suppress that a raw material film is contaminated by the dew condensation water adhering to the outer wall surface of the opening part for conveyance adhering to the raw material film currently passing the opening of the opening part for conveyance. Therefore, the condensed water adhering to the raw material film is subsequently dried to suppress appearance defects such as drying marks on the obtained optical film, and the curl state, optical characteristics, etc. of the obtained optical film, etc. It is possible to suppress adverse effects on various characteristics of the.

  Hereinafter, preferred embodiments of the optical film manufacturing apparatus of the present invention will be described with reference to the drawings.

[First Embodiment]
(Optical film manufacturing equipment with suction device)
In FIG. 1, the side view which represents typically the humidity control furnace vicinity of the manufacturing apparatus 1 of an optical film is shown. The optical film manufacturing apparatus 1 performs a humidity control process for adjusting the moisture content on the raw material film 5 that is continuously conveyed by being unwound from a wound body wound with a long raw material film. This is an apparatus for producing an optical film. The arrows in FIG. 1 indicate the conveyance direction of the raw material film 5.

  The optical film manufacturing apparatus 1 has a humidity control furnace 3 as shown in FIG. 1, and the humidity control process for the raw material film 5 is performed while conveying the raw material film 5 to the humidity control furnace 3. In the humidity control furnace 3 shown in FIG. 1, the inside is divided into two, and a humidity control process can be performed in two stages. The humidity control furnace 3 is provided with a transfer opening 30 having an opening 31 for carrying the raw material film 5 into or out of the humidity control furnace 3. The transfer opening 30 is an area including the opening 31 and the outer wall of the humidity control furnace 3 that forms the periphery of the opening 31. The outer wall of the humidity control furnace 3 that forms the periphery of the opening 31 is usually the outer periphery of the opening 31. Refers to the outer wall in the range of 1m or less. In addition, the optical film manufacturing apparatus 1 includes a suction device 7 as a dew condensation suppressing device for suppressing dew condensation on the outer wall surface of the transfer opening 30 of the humidity control furnace 3.

(Humidity control furnace)
The humidity control furnace 3 performs a humidity control process on the raw material film 5 while conveying the raw material film 5. For example, the moisture content of the raw material film 5 is adjusted by the humidity control atmosphere in the humidity control furnace 3. Can do. By adjusting the moisture content of the raw material film 5 by the humidity control in the humidity control furnace 3, the curl state, optical characteristics, etc. of the optical film can be adjusted to a desired state. The humidity control atmosphere in the humidity control furnace 3 may be set as appropriate according to the type of raw material film and the humidity control processing conditions. The humidity can be adjusted to 30 RH% or more, and when the dehumidifying process is performed as the humidity control process, the temperature can be adjusted to 30 to 100 ° C. and the humidity can be adjusted to less than 30 RH%.

  The number of humidity control furnaces 3 provided in the optical film manufacturing apparatus 1 may be one or two or more. Moreover, the inside of the humidity control furnace 3 may be one space, and is divided into two or more stages, for example, as shown in FIG. 1 according to the conditions of the humidity control process performed in the humidity control furnace 3. The humidity conditioning process may be performed.

  The humidity control furnace 3 is adjusted to a humidity control atmosphere having a temperature and humidity corresponding to the humidity control conditions by the humidity control gas that fills the internal space, and thereby the moisture content of the raw material film 5 is set to a desired level. Can be adjusted. The humidity control furnace 3 can include a humidity controller (not shown) for making the inside of the humidity control furnace 3 a predetermined humidity control atmosphere. As the humidity controller, a publicly known one can be used according to the humidity control condition. For example, by supplying a humidity control gas into the humidity control furnace 3, the humidity control condition in the humidity control furnace 3 can be adjusted. It is possible to adjust the humidity control atmosphere accordingly.

  The humidity control furnace 3 may be a humidification furnace that performs a humidification process to increase the moisture content in the raw material film 5, and is a dehumidification furnace that performs a dehumidification process to reduce the moisture content in the raw material film 5. There may be. The phenomenon in which the outer wall surface of the opening 30 for transporting due to the humidity-controlling gas that has flowed out of the humidity-controlling furnace 3 is likely to occur when the humidity-controlling furnace 3 is a humidification furnace, and thus the optical film of the present embodiment is manufactured. The apparatus 1 can be used particularly suitably when the humidity control furnace 3 is a humidification furnace and a humidification process is performed in the humidification furnace.

  The humidity control furnace 3 is provided with a transport opening 30 having an opening 31 for carrying the raw material film 5 before humidity control into the humidity control furnace 3 or carrying out the raw material film 5 after humidity control. ing. As shown in FIG. 1, the transport opening 30 includes a carry-in part 30 a having a carry-in opening 31 a that is an opening for carrying the raw material film 5 before humidity control into the humidity control furnace 3, and a post-humidity control unit. The unloading part 30b which has the opening 31b for unloading which is an opening for unloading the raw material film 5 can be provided. In addition, although the example which has the carrying-in part 30a and the carrying-out part 30b one each in the humidity control furnace 3 is shown in FIG. 1, a carrying-in part may serve as a carrying-out part, for example, humidity control In order to convey a plurality of raw material films in the furnace 3, etc., it may have two or more carry-in sections and carry-out sections.

  The humidity control furnace 3 can be provided with a plurality of guide rolls that support the material film 5 to be conveyed. The plurality of guide rolls arranged in the humidity control furnace 3 are adjacent to the upper roll 61 arranged on the upper side in the humidity control furnace 3 on the lower side in the humidity control furnace, for example, as shown in FIG. A lower roll 62 disposed between the upper rolls 61. Thereby, in each division in the humidity control furnace 3, since the raw material film 5 can be supported alternately by the upper roll 61 and the lower roll 62, and the raw material film 5 can be conveyed zigzag, The conveyance path of the raw material film 5 can be lengthened to improve the humidity control efficiency, and the humidity control furnace 3 can be downsized.

(Suction device)
The suction device 7 sucks and collects the humidity control gas that flows out from the opening 31 of the transfer opening 30 among the humidity control gas that forms the humidity control atmosphere in the humidity control furnace 3. Since the humidity control gas contains water vapor, which is a condensable component, when it flows out of the humidity control furnace 3 and is cooled or the like, the water vapor is condensed and condensation tends to occur. The suction device 7 sucks the humidity control gas flowing out of the humidity control furnace 3, thereby reducing water vapor released into the atmosphere outside the humidity control furnace 3, and condensation on the outer wall surface of the transfer opening 30. Can be suppressed.

  The suction device 7 can be installed in at least one of the transfer openings 30 provided in the humidity control furnace 3, and as shown in FIG. 1, all the transfer openings 30 of the humidity control furnace 3. You may install in. The suction device 7 is, for example, a suction box. The suction box, for example, has a box shape such as a rectangular parallelepiped as a whole, and has a large number of through holes for sucking the humidity control gas on one surface, and the humidity control gas sucked into the suction box on the other surface. It has an exhaust hole for discharging.

  The suction device 7 is preferably provided outside the humidity control furnace 3 in order to prevent condensation on the outer wall surface of the transfer opening 30. Further, in order to reduce the humidity control gas released into the atmosphere outside the humidity control furnace 3, the suction device 7 is provided with a transport opening on at least one of the upper side and the lower side of the film surface of the raw material film 5. It is preferable to install along the opening 31 of 30, and it is preferable that this opening 31 has the same width as the width | variety of the width direction of a raw material film or a width | variety wider than it. As shown in FIG. 1, the suction device 7 can be provided on both the upper side and the lower side of the film surface. However, when the outer wall surface of the transport opening 30 is condensed, the condensed water generated by the dew condensation is reduced by its own weight. The suction device 7 may be attached to the raw material film 5 that passes through the opening 31 of the conveyance opening 30, so that the suction device 7 can pass through the opening 31 of the conveyance opening 30 of the humidity control furnace 3. 5 is preferably arranged at least above the film surface.

  Even if the suction device 7 has a heating unit that heats the humidity control gas in order to prevent the water vapor in the humidity control gas sucked into the suction device 7 from condensing and condensing the suction device 7. Good. Thereby, the sucked humidity control gas is cooled in the suction device 7, the water vapor in the humidity control gas is condensed, and the generation of dew condensation water in the suction device 7 is suppressed. It is possible to suppress contamination. As the heating unit, a known heating device can be used, and examples thereof include a heater, a resistance heating element, an induction heating device, and a microwave irradiation device. It is preferable that the heating unit heats the suction device 7 so that the temperature becomes higher than the dew point temperature of the humidity control gas in the humidity control furnace 3.

(Raw material film and optical film)
The optical film manufactured by the optical film manufacturing apparatus 1 is obtained by performing at least a humidity control process on a raw material film. As an optical film, a polarizing film, a protective film bonded to the polarizing film, a polarizing plate having a protective film bonded to one or both surfaces of the polarizing film, a retardation film, a brightness enhancement film, a reflective film, an antiglare film Examples thereof include films having an optical function used in image display devices and the like, such as antireflection films, transflective films, and light diffusion films. The raw material film is a raw material film used for producing these optical films and is at least before being subjected to a humidity control treatment.

  The polarizing film is preferably a linear polarizer, and a film obtained by adsorbing and orienting a dichroic dye such as iodine or a dichroic dye on a uniaxially stretched polyvinyl alcohol resin layer can be used. Such a polarizing film can be produced, for example, by subjecting a polyvinyl alcohol resin film to uniaxial stretching, dyeing with a dichroic dye, boric acid treatment, water washing treatment, and the like. When the optical film is a polarizing film, the humidity control treatment is performed, for example, to adjust the moisture content of the raw material film for producing the polarizing film after the heat drying performed after the water washing treatment.

  The protective film may be a simple protective film having no optical function, or may be a protective film having both optical functions such as a retardation film and a brightness enhancement film. Although it does not specifically limit as a material of a protective film, The thermoplastic resin which has translucency can be used. Examples of such thermoplastic resins include chain polyolefin resins such as polypropylene resins, cyclic polyolefin resins such as norbornene resins, cellulose acetate resins such as triacetyl cellulose and diacetyl cellulose, polyethylene terephthalate, polyethylene naphthalene. Examples of the thermoplastic resin known in the art include polyester resins such as phthalate and polybutylene terephthalate, polycarbonate resins, and (meth) acrylic resins. In the present specification, “(meth) acryl” means at least one selected from acryl and methacryl. When the optical film is a protective film, the humidity control treatment is performed to adjust the moisture content of the raw material film for producing the protective film, for example, before being bonded to the polarizing film.

  When the optical film is a polarizing plate, the humidity control treatment is performed, for example, to adjust the moisture content of the laminate in which the polarizing film and the protective film are bonded.

  The thickness of the raw material film is not particularly limited, and may be usually 1 μm or more, preferably 2 μm or more, more preferably 5 μm or more, and usually 200 μm or less, and 100 μm or less. Is preferably 50 μm or less, and more preferably 20 μm or less. The optical film manufacturing apparatus 1 provided with the suction device 7 can be used when the raw material film is brought into or out of the humidity control furnace even when the thickness of the raw material film is as small as 1 μm or more and 20 μm or less. Since it is difficult to cause poor conveyance such as flapping, wrinkling, folding, etc., it can be suitably used particularly when performing a humidity conditioning treatment on a thin raw material film.

  The thickness of the optical film obtained by subjecting the raw material film to at least humidity control is not particularly limited, but is usually 1 μm or more and 200 μm or less, and when the optical film is a polarizing film, the thickness is 5 μm or more and 30 μm or less. When the optical film is a protective film, the thickness is from 10 μm to 80 μm, and when the optical film is a polarizing plate, the thickness is from 30 μm to 200 μm.

(Manufacturing method of optical film using suction device)
In the optical film manufacturing apparatus 1 shown in FIG. 1, the raw material film 5 before humidity control is continuously carried into the humidity control furnace 3 from the carry-in part 30 a of the humidity control furnace 3, and the humidity control in the humidity control furnace 3 is performed. The humidity-treated raw material film that has been subjected to the treatment is unloaded from the unloading section 30 b of the humidity-control furnace 3. At this time, the inside of the humidity control furnace 3 is filled with a humidity control gas according to the humidity control processing conditions, and the carrying-in part 30a and the carrying-out part 30b that are the transfer opening 30 of the humidity control furnace 3 have A carry-in opening 31a and a carry-out opening 31b for the raw film 5 to pass through are provided. Therefore, the humidity control gas in the humidity control furnace 3 may flow out from the loading opening 31a and the unloading opening 31b. The water vapor in the humidity control gas that has flowed out of the humidity control furnace 3 may condense depending on conditions such as temperature, humidity, and pressure outside the humidity control furnace 3, and the outer wall surface of the transfer opening 30 may be condensed.

  In the optical film manufacturing apparatus 1, the suction device 7 provided in the transport opening 30 of the humidity control furnace 3 sucks and collects the humidity control gas that has flowed out of the humidity control furnace 3, thereby opening the transport opening. Condensation suppression processing is performed to suppress condensation on the outer wall surface of the portion 30. Thereby, it is possible to prevent the condensed water adhering to the outer wall surface of the conveyance opening 30 from contaminating the raw material film 5 by dropping onto the raw material film 5 passing through the opening 31 of the conveyance opening 30. it can. Moreover, when the suction device 7 has a heating part, the heating process which heats the humidity control gas which the suction device 7 attracted | sucked by a heating part can be performed. Thereby, since it can suppress that the water vapor | steam in the humidity control gas attracted | sucked by the suction apparatus 7 can condense, dew condensation water adheres to the suction apparatus 7, and this dew condensation water contaminates the raw material film 5. Therefore, an optical film with good quality can be obtained.

  The suction device 7 is provided outside the humidity control furnace 3 along at least the upper side of the film surface of the raw material film 5 along the opening 31 of the transfer opening 30, thereby containing water vapor that causes condensation. Wet gas can be sucked efficiently. In particular, when the humidity control gas is supplied from the humidity controller to the humidity control furnace 3 as described above, the pressure (internal pressure) in the humidity control furnace 3 is the pressure outside the humidity control furnace 3 (external pressure). Therefore, the humidity control gas in the humidity control furnace 3 is more likely to flow out of the humidity control furnace 3 through the opening 31 of the transfer opening 30. Therefore, by providing a suction device outside the humidity control furnace 3, the humidity control gas flowing out of the humidity control furnace 3 can be efficiently suctioned. Moreover, by providing the suction device 7 on the upper side of the film surface of the raw film 5, it is possible to efficiently suppress dew condensation on the outer wall surface located on the upper side of the film surface among the outer wall surfaces of the transfer opening 30. can do.

  The suction pressure in the suction device 7 is usually 2.0 kPa or more and 5.0 kPa or less, and the flow rate of the suction gas can be 5 m / s or more and 30 m / s or less.

[Second Embodiment]
(Optical film manufacturing device with air supply device)
The optical film manufacturing apparatus according to the present embodiment is a first implementation in that it is provided with an air supply device as a dew condensation suppressing device instead of the suction device 7 of the optical film manufacturing apparatus 1 according to the first embodiment. It is different from the form. Hereinafter, the description of the same members as those described in the first embodiment will be omitted.

  The optical film manufacturing apparatus 1 according to the present embodiment includes an air supply device as a dew condensation suppressing device for suppressing dew condensation on the outer wall surface of the opening 30 for conveyance. The air supply device supplies air in the form of a curtain to the opening 31 of the transfer opening 30, thereby suppressing the humidity-controlled gas from flowing out of the humidity control furnace 3, Condensation on the outer wall surface of the opening 30 can be suppressed.

(Air supply device)
The air supply device suppresses the flow of humidity-controlled gas in the humidity control furnace 3 from the opening 31 of the transfer opening 30 by supplying air in the form of a curtain to the opening 31 of the transfer opening 30. To do. The air supply device suppresses the outflow of humidity control gas containing water vapor to the outside of the humidity control furnace 3, so that the amount of water vapor released to the outside of the humidity control furnace is reduced, and the periphery of the opening 31 of the transfer opening 30. It is possible to suppress dew condensation on the outer wall surface. The air supply device can be installed in at least one of the transfer openings 30 provided in the humidity control furnace 3, and may be installed in all the transfer openings 30 of the humidity control furnace 3. The optical film manufacturing apparatus may include an air supply device and the suction device described in the first embodiment.

  The air supply device is not particularly limited as long as it can supply air so that curtain-shaped air (curtain flow) is formed in the opening 31 of the transfer opening 30. The air supply device may be, for example, a blow-down system in which air is supplied from the upper side to the lower side of the opening 31 to form a curtain flow, and the air is supplied from both the left and right sides of the opening 31 so as to face each other. It may be a horizontal blowing method in which a curtain flow is formed by supplying. The curtain flow is preferably formed to have the same width as the width of the opening 31 in the width direction of the raw material film or a width wider than that. Further, the curtain flow is preferably formed in the opening 31 of the transfer opening 30 outside the humidity control furnace 3 so as not to adversely affect the transfer of the raw material film 5 in the humidity control furnace 3.

  The temperature of the air supplied by the air supply device is preferably higher than the temperature at which water vapor that is a condensable component in the humidity control gas in the humidity control furnace 3 is condensed (dew point temperature of the humidity control gas). It is usually 1 ° C to 50 ° C. By making the temperature of the air higher than the dew point temperature of the humidity control gas, it is possible to suppress the water vapor in the humidity control gas from being condensed by the air supplied by the air supply device, and dew condensation water is formed on the outer wall surface of the transfer opening. It can suppress adhering. Usually, the temperature of the supplied air may be 3 ° C. or more higher than the dew point temperature of the humidity control gas, and the humidity of the supplied air may be 40% RH or less.

  The blow-out speed of the air supplied by the air supply device can be arbitrarily selected within a range that does not adversely affect the conveyance of the raw material film, and depends on the size of the opening 31 of the conveyance opening 30 and the thickness of the raw material film 5. However, it is usually 2 m / sec or more, preferably 4 m / sec or more, usually 20 m / sec or less, and preferably 15 m / sec or less.

(Manufacturing method of optical film using air supply device)
Also in the optical film manufacturing apparatus of the present embodiment, the raw material film 5 before humidity control is continuously humidity-controlled from the carry-in part 30a of the humidity control furnace 3, as in the optical film manufacturing apparatus 1 shown in FIG. The raw material film after humidity control carried in the furnace 3 and subjected to the humidity control process in the humidity control furnace 3 is transported from the transporting part 30 b of the humidity control furnace 3. At this time, the air supply device supplies air in the form of a curtain to the opening 31 of the transfer opening 30 of the humidity control furnace 3, thereby preventing condensation on the outer wall surface of the transfer opening 30. A suppression process is performed.

  The amount of humidity control gas flowing out from the humidity control furnace 3 to the outside of the humidity control furnace 3 is reduced by the curtain-shaped air supplied from the air supply device, and water vapor flows out of the humidity control furnace 3 from the humidity control furnace 3. The amount of is reduced. Thereby, the outer wall surface of the conveyance opening 30 is condensed, and the condensed water generated by the condensation is contaminated on the raw material film 5 by dropping onto the raw material film 5 passing through the opening 31 of the conveyance opening 30. This can be suppressed and a good quality optical film can be obtained. Further, the temperature of the air supplied from the air supply device is made higher than the dew point of the humidity control gas, so that the water vapor in the humidity control gas is prevented from condensing and condensation is formed on the outer wall surface of the transport opening 30. It is possible to further suppress the adhesion of water.

  As described above, when the humidity control gas is supplied into the humidity control furnace 3 from the humidity controller, the pressure inside the humidity control furnace 3 (internal pressure) becomes higher than the pressure outside the humidity control furnace 3 (external pressure). Therefore, the humidity control gas in the humidity control furnace 3 easily flows out of the humidity control furnace 3 through the opening 31 of the transfer opening 30. Therefore, by providing an air supply device outside the humidity control furnace 3 and supplying curtain-like air to the opening 31 of the transfer opening 30, the humidity control gas that is likely to cause dew condensation is removed from the humidity control furnace 3. It is possible to prevent the transport opening 30 from condensing.

[Third Embodiment]
(Optical film manufacturing equipment equipped with a heating device)
The optical film manufacturing apparatus according to the present embodiment is a first implementation in that it is provided with a heating device as a dew condensation suppressing device instead of the suction device 7 of the optical film manufacturing apparatus 1 according to the first embodiment. It is different from the form. Hereinafter, the description of the same members as those described in the first embodiment will be omitted.

  The optical film manufacturing apparatus of the present embodiment includes a heating device as a dew condensation suppressing device for suppressing dew condensation on the outer wall surface of the conveyance opening. The heating device heats the outer wall surface of the opening 30 for conveyance. Thereby, even when the humidity control gas flows out of the humidity control furnace 3, the humidity control gas that flows out of the humidity control furnace 3 is used. When the body is cooled outside the humidity control furnace 3, it is possible to prevent water vapor in the humidity control gas from adhering to the outer wall surface of the transfer opening 30 as condensed water.

(Heating device)
The heating device warms the outer wall surface of the transfer opening 30 to suppress the dew condensation on the outer wall surface of the transfer opening 30 from the moisture in the humidity control gas that has flowed out of the humidity control furnace 3. To do. When the heating device heats the outer wall surface of the transfer opening 30, the outer wall surface prevents the water vapor in the humidity control gas flowing out of the humidity control furnace 3 from being cooled, and the transfer opening Condensation on the outer wall surface of the portion 30 can be suppressed. The heating device can be installed in at least one of the transfer openings 30 provided in the humidity control furnace 3, and may be installed in all the transfer openings 30 of the humidity control furnace 3. Moreover, the optical film manufacturing apparatus has either the suction apparatus described in the first embodiment, the air supply apparatus described in the second embodiment, or both of them together with the heating apparatus. It may be.

  The heating device is not particularly limited as long as it can directly or indirectly heat the outer wall surface of the transfer opening 30, and a known heating device can be used. Examples of the heating device include a heater, a resistance heating element, an induction heating device, and a microwave irradiation device.

  The heating device heats the outer wall surface of the transfer opening 30 to a temperature higher than the temperature at which water vapor, which is a condensable component in the humidity control gas in the humidity control furnace 3, is condensed (dew point temperature of the humidity control gas). It is preferable to warm. By heating the outer wall surface of the transfer opening 30 to a temperature higher than the dew point temperature of the humidity control gas by a heating device, it is possible to suppress the water vapor contained in the humidity control gas from being cooled by the outer wall surface, It is possible to suppress water vapor from adhering to the outer wall surface as condensed water. The temperature of the outer wall surface may be usually higher by 3 ° C. than the dew point temperature of the humidity control gas.

  The optical film manufacturing apparatus equipped with a heating device flutters the raw material film when the raw material film is brought into or out of the humidity control furnace even when the thickness of the raw material film is as small as 1 μm or more and 20 μm or less. In addition, since it is difficult to cause conveyance failures such as wrinkles and folds, it can be suitably used particularly when performing a humidity control treatment on a thin raw material film.

(Optical film manufacturing method using a heating device)
Also in the optical film manufacturing apparatus of the present embodiment, the raw material film 5 before humidity control is continuously humidity-controlled from the carry-in part 30a of the humidity control furnace 3, as in the optical film manufacturing apparatus 1 shown in FIG. The raw material film 5 after being brought into the furnace 3 and subjected to the humidity control process in the humidity control furnace 3 is carried out from the carry-out part 30 b of the humidity control furnace 3. At this time, a dew condensation suppressing process is performed in which the heating device warms the outer wall surface of the transfer opening 30 of the humidity control furnace 3 to prevent condensation on the outer wall surface of the transfer opening 30.

  When the heating device heats the outer wall surface of the transfer opening 30, it is possible to suppress the water vapor contained in the humidity control gas flowing out of the humidity control furnace 3 from being cooled by the outer wall surface. Thereby, it can suppress that the water vapor | steam contained in humidity control gas becomes dew condensation water, and adheres to the outer wall surface of the opening part 30 for conveyance, and can obtain the optical film of favorable quality. Further, by heating the outer wall surface of the transfer opening 30 to a temperature higher than the dew point temperature of the humidity control gas by the heating device, the water vapor of the humidity control gas flowing out of the humidity control furnace 3 is cooled. Condensation can be suppressed, and condensation on the outer wall surface of the transfer opening 30 can be further suppressed.

  As described above, when the humidity control gas is supplied into the humidity control furnace 3 from the humidity controller, the pressure inside the humidity control furnace 3 (internal pressure) becomes higher than the pressure outside the humidity control furnace 3 (external pressure). Therefore, the humidity control gas in the humidity control furnace 3 easily flows out of the humidity control furnace 3 through the opening 31 of the transfer opening 30. Therefore, by heating the outer wall surface of the transfer opening 30 with a heating device, even if the humidity control gas that tends to cause dew condensation flows out of the humidity control furnace 3, the outer wall surface of the transfer opening 30 Since it can suppress that it is cooled, it can suppress that the opening part 30 for conveyance condenses.

  DESCRIPTION OF SYMBOLS 1 Optical film manufacturing apparatus, 3 Humidity control furnace, 5 Raw material film, 7 Suction apparatus (condensation suppression apparatus), 30 Conveyance opening part, 30a Carry-in part, 30b Carry-out part, 31 opening, 31a Carry-in opening, 31b For carrying out Opening, 61 Upper roll, 62 Lower roll

Claims (15)

An apparatus for producing an optical film that performs humidity conditioning for adjusting the moisture content of the raw material film while conveying the raw material film,
A humidity control furnace for carrying out the humidity control process, having one or more openings for conveyance having an opening for carrying in or carrying out the raw material film;
A dew condensation suppressing device for suppressing dew condensation on the outer wall surface of the opening for conveyance;
The said dew condensation suppression apparatus is an optical film manufacturing apparatus installed in at least one of the said opening parts for conveyance.   The said humidity control furnace is a manufacturing apparatus of the optical film of Claim 1 which is a humidification furnace which performs the humidification process which humidifies the said raw material film. The dew condensation suppression device is
A suction device for sucking the humidity control gas in the humidity control furnace flowing out of the opening of the transfer opening;
An air supply device for supplying air in a curtain shape to the opening of the transfer opening; and
The optical film manufacturing apparatus according to claim 1, wherein the apparatus is at least one of a heating device for heating the outer wall surface of the opening for conveyance. The dew condensation suppression device is the suction device;
The said suction device is installed along the said opening at least above the film surface of the said raw material film which is the exterior of the said humidity control furnace, and passes the said opening of the said opening part for conveyance. The manufacturing apparatus of the optical film as described in any one of. The dew condensation suppression device is the suction device;
The optical film manufacturing apparatus according to claim 3 or 4, wherein the suction device is a suction box. The dew condensation suppression device is the suction device;
The said suction device is a manufacturing apparatus of the optical film of any one of Claims 3-5 which further has a heating part for heating the said humidity control gas attracted | sucked. The dew condensation suppression device is the air supply device,
The temperature of the said air which the said air supply apparatus supplies is a temperature higher than the dew point temperature of the said humidity control gas, The manufacturing apparatus of the optical film of Claim 3. A method for producing an optical film that performs humidity conditioning to adjust the moisture content of the raw material film while conveying the raw material film,
The humidity control treatment is performed in a humidity control furnace having at least one opening for transporting with an opening for carrying in or carrying out the raw material film,
The manufacturing method of the optical film which performs the dew condensation suppression process which suppresses that the outer wall surface of the said opening for conveyance dew condensation in at least one of the said opening parts for conveyance.   The method for producing an optical film according to claim 8, wherein the humidity adjustment process is a humidification process. The dew condensation suppressing process is
A suction process for sucking humidity-controlled gas in the humidity-control furnace flowing out of the opening of the transfer opening;
An air supply process for supplying air in a curtain shape to the transfer opening; and
The manufacturing method of the optical film of Claim 8 or 9 which is at least one of the heating processes which heat the said outer wall surface of the said opening part for conveyance. The dew condensation suppression process is at least one of the suction process and the heating process,
The thickness of the said raw material film is a manufacturing method of the optical film of Claim 10 which is 1 micrometer or more and 200 micrometers or less. The dew condensation suppression process is the suction process,
In the suction process, the humidity control gas is sucked along the opening at least on the upper side of the film surface of the raw material film that is outside the humidity control furnace and passes through the opening of the opening for conveyance. The manufacturing method of the optical film of Claim 10 or 11. The dew condensation suppression process is the suction process,
Furthermore, the manufacturing method of the optical film of any one of Claims 10-12 which performs the heat processing which heats the said humidity control gas attracted | sucked by the said attraction | suction process. The dew condensation suppression process is the air supply process,
The temperature of the said air supplied in the said air supply process is a manufacturing method of the optical film of Claim 10 which is temperature higher than the dew point temperature of the said humidity control gas in the said humidity control furnace.   The optical film is any one of a polarizing film, a protective film bonded to the polarizing film, and a polarizing plate in which the protective film is bonded to one surface or both surfaces of the polarizing film. The manufacturing method of the optical film of any one of 8-14.

Images