Method for manufacturing optical film

Abstract

A method for manufacturing a humidified optical film by humidifying a film raw material (1) including a polarizer, the film raw material (1) having the polarizer being blown with water vapor at a temperature of 35 DEG C or more and 80% RH or more at a pressure of 0.5 kPa or more. For example, by blowing the water vapor from an arc-shaped surface part (711) of a blowing part (7) to the film raw material (1), the tension of the film raw material (1) and the blowing pressure of the water vapor balance each other, and the film raw material (1) is separated from the arc-shaped surface part (711) and conveyed along the arc-shaped surface part (711).

Description

Technical Field

[0001] The present invention relates to a method for producing an optical film including a polarizing plate. Background Art

[0002] At present, as a constituent material of a liquid crystal display device, polarized sunglasses, etc., an optical film including a polarizer can be used. As the optical film, for example, a laminated film having a protective film laminated on a polarizer, a laminated film having a phase difference film laminated on a polarizer, etc. can be cited.

[0003] The optical film may be produced by subjecting the film material including the polarizing plate to any treatment, and one of the treatments is known to be subjecting the film material to a humidification treatment.

[0004] For example, Patent Document 1 discloses that in order to adjust the moisture content of a film raw material (raw material film), the film raw material is guided into a humidity control furnace and conveyed in a humidified environment in the humidity control furnace.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent document 1: (Japan) Patent Publication No. 2019-28285. Summary of the invention

[0008] Technical problem to be solved by the invention

[0009] As described above, by subjecting the film raw material to a humidification treatment, an optical film that is unlikely to bend over time can be manufactured.

[0010] However, the humidification method of Patent Document 1 requires a relatively long time to make the film raw material contain a predetermined amount of water. If the humidification treatment is performed for a long time, not only the production efficiency of the optical film is deteriorated, but also the size of the device is increased.

[0011] Furthermore, if condensation occurs on the film material including the polarizer during the humidification treatment, there is a risk that an optical film having a poor appearance may be obtained.

[0012] It should be noted that a method for preventing condensation from forming on the outer wall surface of a humidity control furnace is disclosed in Patent Document 1. However, Patent Document 1 does not disclose or suggest a method for preventing condensation from forming on a film raw material in a humidity control furnace.

[0013] A first object of the present invention is to provide a method for humidifying a film material including a polarizing plate in a relatively short time.

[0014] A second object of the present invention is to prevent condensation from occurring during humidification treatment of a film raw material and to produce an optical film having excellent optical properties.

[0015] Technical solutions for solving technical problems

[0016] The method for producing an optical film according to the first embodiment of the present invention produces a humidity-controlled optical film by humidifying a film material including a polarizer, wherein water vapor at a temperature of 35° C. or higher and a relative humidity of 80% or higher is sprayed onto the film material including the polarizer at a pressure of 0.5 kPa or higher.

[0017] In the method for producing an optical film according to a second embodiment of the present invention, in the method for producing an optical film according to the first embodiment, the polarizer is a dyed and stretched hydrophilic polymer film.

[0018] A method for producing an optical film according to a third embodiment of the present invention is the method for producing an optical film according to the first or second embodiment, wherein the film material comprises the polarizer and a protective film laminated on the polarizer.

[0019] A method for producing an optical film according to a fourth embodiment of the present invention is the method according to any one of the first to third embodiments, wherein the time for spraying the water vapor at the pressure onto the film material is 10 seconds or longer.

[0020] The manufacturing method of the optical film of the fifth embodiment of the present invention is the manufacturing method of any one of the first to fourth embodiments, wherein the film raw material is guided into a chamber adjusted to a predetermined ambient temperature, and water vapor of the pressure is sprayed onto the film raw material while the film raw material is being transported in the chamber.

[0021] According to a sixth embodiment of the present invention, in the manufacturing method of the fifth embodiment, the ambient temperature in the chamber is within a range of -5°C or higher than the temperature of the water vapor and +20°C or lower than the temperature of the water vapor.

[0022] A seventh embodiment of the optical film manufacturing method of the present invention is the manufacturing method of the sixth embodiment, wherein the film material is transported in the chamber for more than 3 seconds before the water vapor is sprayed onto the film material.

[0023] The manufacturing method of the optical film of the eighth embodiment of the present invention is the manufacturing method of the fifth embodiment described above, wherein a blowing section having an arc-shaped surface is arranged in the chamber, and a plurality of ejection holes are formed in the arc-shaped surface. During the period when the film raw material is transported along the arc-shaped surface in a tensioned state, the water vapor is sprayed toward the film raw material from the ejection holes, and the tension of the film raw material and the blowing pressure of the water vapor balance each other, and the film raw material leaves the arc-shaped surface and is transported along the arc-shaped surface.

[0024] In the manufacturing method of the optical film of the ninth embodiment of the present invention, in the manufacturing method of the fifth embodiment described above, a blowing section having a flat surface is arranged in the chamber, and a plurality of point-shaped ejection holes are formed on the flat surface. While the film raw material is being transported along the blowing section in a tensioned state, the water vapor is sprayed from the ejection holes in a vertical direction relative to one side of the film raw material.

[0025] The manufacturing method of the optical film of the tenth embodiment of the present invention is the manufacturing method of the first to ninth embodiments, wherein the film raw material comprises the polarizer, a first film and a second film respectively stacked on one side and the opposite side of the polarizer, the moisture permeability of the first film is higher than that of the second film, and the water vapor is sprayed from at least the first film side.

[0026] Effects of the Invention

[0027] According to the method for manufacturing an optical film of the present invention, the humidification treatment of the film raw material including the polarizer can be completed in a relatively short time. The obtained optical film contains an appropriate amount of moisture and is unlikely to bend and deform over time.

[0028] Furthermore, according to the preferred production method of the present invention, condensation can be prevented from occurring on the film raw material during the humidification process, so that the obtained optical film has suitable optical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a partially omitted top view of the film material of the present invention.

[0030] Figure 2 This is a diagram showing an example of a layer structure of a thin film material.

[0031] Figure 3 It is a diagram showing another example of the layer structure of the film raw material.

[0032] Figure 4 It is a diagram showing still another example of the layer structure of the film raw material.

[0033] Figure 5 This is a schematic side view of an optical film production system.

[0034] Figure 6 It is a side view of the humidifying device according to the first embodiment, and is a side view including a cross section of the chamber and the like cut along the conveyance direction of the film material.

[0035] Figure 7 is a top view of the same humidifying device.

[0036] Figure 8 It is along Figure 7 An enlarged cross-sectional view showing the film raw material and the blowing part taken along line VIII-VIII.

[0037] Fig. 9 This is a reference perspective view showing a thin film material and a blowing unit in the chamber according to the first embodiment.

[0038] Fig.10 (a) and (b) are reference plan views respectively showing the arrangement of the ejection holes of the blowing part.

[0039] Fig.11 It is a side view of the humidifying device according to the second embodiment, and is a side view including a cross section of the chamber and the like cut along the conveyance direction of the film material.

[0040] Fig.12 This is an enlarged cross-sectional view showing a film material and a spraying portion of the humidifying device.

[0041] Fig.13 This is a reference perspective view showing a thin film material and a blowing unit in a chamber according to a second embodiment.

[0042] Fig.14 This is a reference perspective view showing a blowing portion according to a modified example of the second embodiment.

[0043] Fig.15 This is an enlarged cross-sectional view showing a cutaway portion of a humidifier according to still another modified example of the second embodiment.

[0044] Fig.16 This is a reference plan view showing a thin film material and a blowing unit in a chamber according to a third embodiment. DETAILED DESCRIPTION

[0045] In this specification, when a plurality of numerical ranges are recorded, such as above the lower limit value and below the upper limit value, any lower limit value or any upper limit value can be selected to set the numerical range of "above any lower limit value" or "below any upper limit value". In this specification, "approximately" means the range allowed in the technical field to which the present invention belongs. In this specification, even if there is a first or second added at the beginning of a word, the first, etc. are only added to distinguish the words and do not have special meanings such as order, superiority, etc.

[0046] [Film materials and optical films]

[0047] Figure 1 It is a partially omitted top view of the film material 1 of the present invention.

[0048] The optical film of the present invention is obtained by at least humidifying the film raw material 1. Therefore, the optical film is a film including a polarizer that has been at least humidified. As required, the optical film can be manufactured by subjecting the film raw material 1 to any appropriate treatment other than humidification before or after the humidification.

[0049] As the film raw material 1 to be processed Figure 1 As shown, generally, it is in the shape of a long strip. The long strip is a generally rectangular shape in a plan view, in which the length in the long side direction is sufficiently longer than the length in the width direction.

[0050] The film material 1 includes a polarizing plate.

[0051] A polarizer is an optical element that has the property of transmitting light vibrating only in a specific direction (polarized light) and blocking light vibrating in directions other than the aforementioned direction (this property is polarization property). Examples of polarizers include hydrophilic polymer films dyed with dichroic substances and stretched. The hydrophilic polymer films have polarization properties.

[0052] As the hydrophilic polymer film, there can be cited a film formed of a hydrophilic polymer; a film obtained by coating a coating liquid containing a hydrophilic polymer on one side of a supporting film and drying the coating liquid. The supporting film can be a colorless and transparent resin film, for example, an ester resin film such as a polyethylene terephthalate resin can be used. As the hydrophilic polymer, for example, polyvinyl alcohol (PVA) resin, ethylene-vinyl alcohol copolymer, etc. can be cited. Preferably, as the hydrophilic polymer film, a film formed of a hydrophilic polymer can be used.

[0053] Figures 2 to 4 Several layers of the film material 1 are shown. Figure 2 is from Figure 1 A diagram of a thin film raw material 11 of a layer structure example observed in the direction of arrow II, Figure 3 as well as Figure 4 Likewise from Figure 1 Figure 1 is a diagram of film raw materials 12 and 13 of other layer structure examples observed in the direction of arrow II.

[0054] Reference Figure 2 A film raw material 11 of a layered structure example includes a polarizer 2, a first film 31 and a second film 32 respectively laminated on one side and the opposite side of the polarizer 2. A first adhesive layer 41 for bonding the polarizer 2 and the first film 31 is sandwiched between the polarizer 2 and the first film 31, and a second adhesive layer 42 for bonding the polarizer 2 and the second film 32 is sandwiched between the polarizer 2 and the second film 32.

[0055] Reference Figure 3 The film material 1 of another layer constitution example includes a polarizer 2 and a first film 31 laminated on one surface of the polarizer 2. A first adhesive layer 41 is interposed between the polarizer 2 and the first film 31 for bonding the two.

[0056] Reference Figure 4 In another layer structure example, the film material 1 is formed of only the polarizing plate 2 .

[0057] The first film 31 may be a single-layer film, or a laminated film having two or more layers of films laminated thereon. The second film 32 may be a single-layer film, or a laminated film having two or more layers of films laminated thereon. The laminated film may be a laminated film having two or more layers of films with the same function, or a laminated film having two or more layers of films with different functions. Furthermore, the laminated film may be a laminated film having two or more layers of films directly bonded thereto, or a laminated film having two or more layers of films bonded thereto via an adhesive layer.

[0058] like Figure 2 As shown in FIG. 1 , in the film material 1 in which the first and second films 31 and 32 are provided on both sides of the polarizer 2, the moisture permeability of the first film 31 and the moisture permeability of the second film 32 are not particularly limited. However, when the moisture permeability is too low, water vapor is blocked by the first film 31 and the second film 32, and there is a risk that the polarizer 2 cannot be fully humidified. From this point of view, the moisture permeability of the first and second films 31 and 32 are independent of each other and can be 50 g / m 2 24h or more, preferably 100g / m 2 · 24 hours or more. The upper limits of the moisture permeability of the first and second films 31 and 32 are not particularly limited, but in actual values, they are 900 g / m 2 Less than 24 hours.

[0059] Furthermore, the moisture permeability of the first film 31 and the moisture permeability of the second film 32 may be equal or different. In one example, the moisture permeability of the first film 31 is higher than that of the second film 32. In the case where the moisture permeability of the first film 31 is higher than that of the second film 32, the difference in moisture permeability between the two is not particularly limited. In order to allow the polarizer 2 to absorb moisture efficiently, it is preferred that the difference in moisture permeability between the two is relatively large. In the case where the moisture permeability of the first film 31 is higher than that of the second film 32, the difference in moisture permeability between the two (moisture permeability of the first film 31 - moisture permeability of the second film 32) may be, for example, 50 g / m 2 ·700g / m2 for more than 24h 2 ·24h or less, preferably 100g / m 2 ·600g / m2 for more than 24h 2Less than 24 hours.

[0060] However, the moisture permeability can be measured under the conditions of a temperature of 65° C. and a relative humidity difference of 90% according to JIS Z0208-1976 (aluminum cup method).

[0061] As the first film 31, for example, a protective film, an optical functional film, a release liner, etc. can be used. For example, when the first film 31 is a single-layer film, as the first film 31, a protective film, an optical functional film, etc. can be used. For example, when the first film 31 is a laminated film, as the first film 31, a laminated film in which a protective film and an optical functional film are laminated, a laminated film in which a release liner and a protective film are laminated, a laminated film in which a release liner, an optical functional film, and a protective film are laminated, etc. can be used.

[0062] As the second film 32, for example, a protective film, an optical functional film, a release liner, etc. can be used. For example, when the second film 32 is a single-layer film, as the second film 32, a protective film, an optical functional film, a release liner, etc. can be used. For example, when the second film 32 is a laminated film, as the second film 32, a laminated film in which a release liner and a protective film are laminated, a laminated film in which a release liner, an optical functional film, and a protective film are laminated, a laminated film in which a protective film and an optical functional film are laminated, etc. can be used.

[0063] The protective film is a film used to protect the polarizing plate 2, etc. As the protective film, a colorless and transparent film is typically used.

[0064] The optical functional film is a film used to impart optical functions. Examples of the optical functional film include phase difference film, light diffusion film, brightness enhancement film, anti-glare film, light reflection film, etc. Phase difference film is a film showing optical directional anisotropy, and as a representative example, stretched films such as acrylic resin, cycloolefin resin, and cellulose resin can be cited.

[0065] The release liner is a film used to protect the adhesive layer, and is usually peeled off when the optical film is used. Examples of the release liner include resin films such as polyethylene, polypropylene, polyethylene terephthalate, and polyester films; paper; porous films such as woven fabrics, nonwoven fabrics, and mesh fabrics; and foamed resin films.

[0066] As the adhesive constituting the first adhesive layer 41 and the second adhesive layer 42, for example, a solvent-based adhesive, a non-aqueous emulsion-type adhesive, an aqueous adhesive, a hot melt adhesive, etc. can be used. From the perspective of excellent transparency and heat resistance, an adhesive using an acrylic polymer as a base polymer is preferably used. It should be noted that in this specification, an adhesive generally includes a substance called an adhesive.

[0067] From the viewpoint of moisture permeability, the first adhesive layer 41 is formed using an adhesive having a moisture permeability equal to or higher than that of the first film 31. Similarly, the second adhesive layer 42 is formed using an adhesive having a moisture permeability equal to or higher than that of the second film 32.

[0068] It should be noted that in Figure 2 as well as Figure 3 In the embodiment, the first film 31 is bonded to the polarizer 2 via the first adhesive layer 41, but the first film 31 may be bonded directly to the polarizer 2 (not shown) without the adhesive layer. Figure 2 In the embodiment, the second film 32 is bonded to the polarizing plate 2 via the second adhesive layer 42 . However, the second film 32 may be bonded directly to the polarizing plate 2 (not shown) (without the adhesive layer).

[0069] [First embodiment of a method for producing an optical film including a method for humidifying a film raw material]

[0070] The manufacturing method of the present invention manufactures a humidity-controlled optical film by humidifying a film material including a polarizer. One feature of the present invention is that water vapor at 35° C. or higher and 80% RH or higher is sprayed onto the film material at a pressure of 0.5 kPa or higher.

[0071] Figure 5 This is a schematic diagram of an optical thin film manufacturing system.

[0072] The optical film manufacturing system A has a humidification area for humidifying the film raw material 1. The optical film manufacturing system A may further have a raw material manufacturing area for manufacturing the film raw material 1 including the polarizer 2, a recycling area for rolling up and recycling the obtained optical film, etc. However, the method of the present invention is not limited to the case of being implemented using the manufacturing system A.

[0073] In the raw material manufacturing area of ​​the manufacturing system A of the illustrated example, a polarizing plate manufacturing device B for manufacturing the polarizing plate 2 is provided, and as required, a laminating device C for bonding the first film 31 and / or the second film 32 to the polarizing plate 2 is further provided. In addition, a humidifying device D is provided in the humidifying area. In the recycling area, a winding device E for winding up the optical film 1a is provided.

[0074] <Manufacturing of polarizing plates>

[0075] The polarizer manufacturing apparatus B can, for example, impart polarization properties to a hydrophilic polymer film 2a such as a polyvinyl alcohol resin by a known method. The hydrophilic polymer film 2a imparted with polarization properties is a polarizer. For example, the polarizer manufacturing apparatus B uses a wet treatment method to dye and stretch the hydrophilic polymer film 2a to produce a polarizer.

[0076] The device for manufacturing polarizers using this wet treatment method is currently well known and is briefly described. The polarizer manufacturing device B has a film filling unit 51, a swelling treatment bath 52, a dyeing treatment bath 53, a cross-linking treatment bath 54, a stretching treatment bath 55, a cleaning treatment bath 56, and a drying unit 57 in order from the upstream side. It should be noted that the polarizer manufacturing device B is not limited to the above-mentioned structure. For example, there may be no swelling treatment bath 52, or there may be no stretching treatment bath 55. In the absence of the stretching treatment bath 55, the hydrophilic polymer film 2a is stretched in the dyeing treatment bath 53, etc. In addition, the polarizer manufacturing device B may also have other treatment baths such as an adjustment treatment bath. It should be noted that in this specification, the downstream side refers to the conveying direction side of the film raw material 1 (the forward direction side of the film raw material 1), and the upstream side refers to the opposite side. In addition, the hollow arrows in each figure indicate the conveying direction of the film.

[0077] Next, the manufacturing process of the polarizing plate is briefly described. Figure 5 , unwind the hydrophilic polymer film 2a wound on the roller and loaded in the film loading section 51. The hydrophilic polymer film 2a is transported to the swelling treatment bath 52 and swelled with a swelling liquid such as water or potassium iodide aqueous solution (swelling process). The swollen hydrophilic polymer film 2a is transported to the dyeing treatment bath 53 and dyed with a dyeing liquid containing a dichroic substance such as iodine (dyeing process). The dyed hydrophilic polymer film 2a is transported to the cross-linking treatment bath 54 and cross-linked with a cross-linking liquid such as a boron compound aqueous solution (cross-linking process). The hydrophilic polymer film 2a is transported to the stretching treatment bath 55 and stretched (stretching process). The dyed and stretched hydrophilic polymer film 2a is transported to the cleaning treatment bath 56 and cleaned with a cleaning liquid such as water (cleaning process). The cleaned hydrophilic polymer film 2a is dried by the drying section 57 (drying process). Thus, by subjecting the hydrophilic polymer film 2 a to each step, the hydrophilic polymer film 2 a develops polarization characteristics (that is, the polarizing plate 2 is obtained).

[0078] exist Figure 5In the embodiment, after the polarizer 2 is manufactured, the polarizer 2 is transported to the laminating device C (i.e., the film lamination is performed after the manufacture of the polarizer 2), but the present invention is not limited thereto. For example, if the obtained polarizer 2 is temporarily rolled up on a roll, the polarizer 2 may be unrolled from the roll after being stored and transported as needed, and the first film 31 and the like may be laminated by the laminating device C (not shown).

[0079] <Manufacturing of film raw materials>

[0080] The laminating device C laminates the first film 31 and / or the second film 32 on the polarizing plate 2 .

[0081] The laminating device C is well known in the art. To briefly explain, the laminating device C includes film loading units 611, 612, a coating unit (not shown) for coating the first and second films 31, 32 with adhesive, and a laminating unit 613 for laminating the first and second films 31, 32 to the polarizing plate 2. It should be noted that when the first film 31 and the second film 32 pre-coated with adhesive are used, the coating unit is omitted.

[0082] Reference Figure 5 , respectively unwind the first film 31 wound on the roll loaded in the film loading section 611 and the second film 32 loaded in the film loading section 612. The first film 31 and the second film 32 are guided to the laminating section 613, and the first and second films 31, 32 are bonded to the polarizer 2. It should be noted that, in the case where the first film 31 is formed of two or more laminated films, a plurality of laminating sections may be provided, and after one film is bonded to the polarizer 2, other films may be bonded and overlapped on the film to form the first film 31 formed of laminated films. The same is true for the case where the second film 32 is formed of two or more laminated films.

[0083] Thus, we can get Figure 2 In the illustrated polarizing plate 2 , a first film 31 is bonded to one surface thereof, and a film material 11 of a second film 32 is bonded to the opposite surface (the opposite surface is the surface on the opposite side to the one surface) of the polarizing plate 2 .

[0084] exist Figure 5 In the embodiment, after the film material 1 is manufactured, the film material 1 is transported to the humidifying device D (i.e., humidification is performed after the manufacturing of the film material 1), but the present invention is not limited thereto. For example, if the obtained film material 1 is temporarily rolled up on a roll, the film material 1 may be unrolled from the roll after being stored and transported as needed, and then humidified by the humidifying device D (not shown).

[0085] It should be noted that in making Figure 3In the case of the film raw material 12 having the layer structure shown in FIG. 1 , only the first film 31 is bonded to the polarizing plate 2. Figure 4 In the case of the polarizing plate 2 shown formed of the film material 13, the laminating device C is omitted.

[0086] <Humidification of film raw materials>

[0087] The manufactured film raw material 1 is transported to a humidifying device D and humidified to contain an appropriate amount of water. When manufacturing the polarizer 2, heating and drying are performed, so that the water content of the polarizer 2 contained in the film raw material 1 immediately after the manufacturing becomes very low. The polarizer 2 with a low water content tends to bend and deform easily over time. By humidifying the film raw material 1 containing such a polarizer 2 and increasing the water content of the polarizer 2, an optical film 1a that is difficult to bend and deform over time can be manufactured.

[0088] Figure 6 It is a detailed representation Figure 5 The side view of the humidifier D of the first embodiment shown in FIG. Figure 6 In FIG. 1 , the chamber 62 is shown in a cross section cut along the conveying direction of the film material 1 . Furthermore, in order to easily identify the communication state between each duct and the chamber 62 , the portion connected to the chamber 62 of the duct is shown in a cross section. Figure 7 It is a top view of the humidifier D (a view viewed from above to below). Figure 8 This is a cross-sectional view of the blowing section 7 and the film material 1 cut along the conveying direction, and is a cross-sectional view that easily shows a state in which the film material 1 to which water vapor is blown is conveyed along the blowing section 7 . Fig. 9 2 is a reference perspective view showing a state where the film material 1 is conveyed along the blowing section 7. Fig. 9 In FIG. 1 , the film material 1 is indicated by an imaginary line (two-dot chain line).

[0089] refer to Figures 5 to 9 The humidifier D sprays water vapor at 35°C or higher and 80%RH or higher at a pressure of 0.5 kPa or higher to the conveyed long strip-shaped film material 1 (including the film material of the polarizer). The spraying part 7 of the humidifier D of the first embodiment that sprays water vapor to the film material 1 has an arc-shaped surface 711.

[0090] Specifically, the humidifying device D includes a chamber 62, and a blowing part 7 disposed in the chamber 62 and having an arc-shaped surface 711 formed with a plurality of ejection holes 721. The chamber 62 is a chamber that surrounds the blowing part 7 and has a sufficient space for conveying the film raw material 1. On the upstream side of the chamber 62, a conveying inlet 621 for introducing the film raw material 1 into the chamber 62 is provided, and on the downstream side of the chamber 62, a conveying outlet 622 for conveying the film raw material 1 out of the chamber 62 is provided. In the chamber 62, a guide roller 623 for guiding the conveyance of the film raw material 1 is disposed at an appropriate position. In addition, a pressure regulating mechanism 64 for regulating the ambient pressure of the chamber 62 (the air pressure in the chamber 62) and a temperature regulating mechanism 65 for regulating the ambient temperature of the chamber 62 (the temperature in the chamber 62) are provided in the chamber 62.

[0091] The pressure adjustment mechanism 64 measures the ambient pressure in the chamber 62 and adjusts the ambient pressure in the chamber 62 based on the measured value.

[0092] The temperature adjustment mechanism 65 measures the temperature in the chamber 62 and adjusts the temperature in the chamber 62 based on the measured value.

[0093] The blowing section 7 includes a hollow housing 731 having an arc-shaped surface 711 formed with a plurality of ejection holes 721, and a supply port 741 for supplying water vapor into the housing 731. The arc-shaped surface 711 is arc-shaped when viewed from the side, and the arc extends continuously in the width direction of the film material 1 to form an arc-shaped surface. In the example shown in the figure, the arc-shaped surface 711 is a substantially semicircular arc-shaped surface, but it is not limited to this, and may also be a substantially 1 / 4 arc surface, etc.

[0094] The point-shaped discharge holes 721 formed on the arc-shaped surface 711 are, for example, roughly circular openings when viewed from above. It should be noted that the point-shaped discharge holes 721 are not limited to roughly circular openings, but can also be roughly quadrilateral openings when viewed from above. The size of the discharge hole 721 is not particularly limited. If it is too small, there is a risk of blockage. If it is too large, there is a risk of deviation in the pressure of water vapor. From this point of view, the size of the discharge hole 721 is based on the case where the discharge hole 721 is roughly circular, with a diameter of not less than 0.8 mm and not more than 4.0 mm, and preferably, a diameter of not less than 1.0 mm and not more than 3.0 mm. The size of the discharge hole 721 that is not roughly circular when viewed from above is the equivalent circle diameter.

[0095] like Figure 8 as well as Fig. 9 As shown in FIG. 1 , a plurality of discharge holes 721 are formed at intervals in the circumferential direction (the conveying direction of the film material 1) of the arc-shaped surface portion 711. Fig. 9As shown, a plurality of discharge holes 721 are formed at intervals in the width direction of the film material 1. Therefore, a plurality of dot-shaped discharge holes 721 are formed along the curved surface of the arc-shaped surface portion 711, and a plurality of discharge holes 721 formed along the curved surface are also formed in the width direction.

[0096] The ejection holes 721 may be formed at equal intervals or at random intervals. In order to spray water vapor substantially uniformly toward the film material 1, it is preferred that the plurality of ejection holes 721 be formed at equal intervals.

[0097] Furthermore, the specific arrangement of each discharge hole 721 is not particularly limited and can be appropriately set.

[0098] Fig.10 1 is a plan view showing several examples of the arrangement of the ejection holes 721. When the plurality of ejection holes 721 arranged in the width direction of the film material 1 is referred to as a "row", the row of ejection holes 721 is arranged in a plurality of rows in the conveying direction of the film material 1 (the circumferential direction of the arcuate surface 711). Fig.10 (a) shows a case where the ejection holes 721 in rows adjacent to each other in the conveying direction are arranged without deviation in the width direction (hereinafter, such an arrangement of the ejection holes 721 in a dot pattern is referred to as a grid arrangement). Fig.10 (b) shows a case where the ejection holes 721 in odd columns are arranged offset to the left (or right) in the width direction with respect to the ejection holes 721 in even columns (hereinafter, such an arrangement of the dot-shaped ejection holes 721 is referred to as a staggered arrangement).

[0099] The number of ejection holes 721 formed per unit area is not particularly limited, and can be appropriately set in consideration of the size of the ejection holes 721. For example, the size and number of ejection holes 721 are set in such a way that the opening rate is in the range of 0.2% to 5.0%, preferably in the range of 0.5% to 3.0%. Here, the opening rate is the ratio of the total opening area of ​​the ejection holes 721 per unit area of ​​the arc-shaped surface 711 facing the film raw material 1, which is calculated by the formula: (total opening area of ​​the ejection holes 721 / unit area of ​​the arc-shaped surface 711 of the blowing section 7) × 100. For example, at any 100mm of the arc-shaped surface 711 facing the film raw material 1 2 In the range of 10 discharge holes 721 with a diameter of 2 mm, the opening ratio (%) = (1 mm × 1 mm × π × 10 / 100 mm 2 )×100%.

[0100] Each of the ejection holes 721 is formed through the arc-shaped surface 711 so that the water vapor is ejected along the radial direction of the arc-shaped surface 711 (see Figure 8). By ejecting water vapor from each ejection hole 721 along the radial direction of the arc-shaped surface 711, the water vapor can be ejected in a substantially vertical direction relative to one side of the film material 1 transported along the arc-shaped surface 711 (so that the water vapor is along the substantially thickness direction of the film material 1).

[0101] A supply mechanism for supplying water vapor into the shell 731 of the blowing part 7 is provided at the supply port 741 of the blowing part 7. The supply mechanism includes a steam generator 81, a heating part 82 for heating water vapor, a blower 83 for sending water vapor at a predetermined pressure, a pipeline, and a supply control part 84. Further, preferably, the supply mechanism includes a steam trap. In addition, the supply mechanism may include a temperature sensor, a humidity sensor, a speed sensor, etc. as needed.

[0102] The supply mechanism of the present embodiment generally recovers the water vapor in the chamber 62 , adds water vapor again as needed, heats the water vapor to a predetermined temperature, and supplies the water vapor to the spraying section 7 .

[0103] For example, the supply mechanism may include a pipe, a first steam trap 861, a steam generator 81, a heating unit 82 such as an electric heater, a blower 83, a temperature sensor 87 and a humidity sensor 88, a second steam trap 862, and a supply control unit 84. The supply mechanism is usually provided outside the chamber 62, but a part or all of it may be provided in the chamber 62.

[0104] Reference Figures 5 to 7, the pipeline includes a first pipeline 851, a second pipeline 852, and a third pipeline 853. Among them, the first pipeline 851 is connected to an arbitrary position of the chamber 62 (the water vapor outlet in the chamber 62), the second pipeline 852 is connected to the supply port 741 of the spraying part 7, and the third pipeline 853 is connected between the first pipeline 851 and the second pipeline 852. The steam generator 81, the heating part 82, the blower 83, the temperature sensor 87, the humidity sensor 88, the second steam trap 862, etc. are arranged in the path of the third pipeline 853. The first steam trap 861 is arranged, for example, near the first pipeline 851. The first steam trap 861 allows the water vapor in the chamber 62 taken out through the first pipeline 851 to pass through the third pipeline 853 without condensation water. Here, the steam trap (also called a drainer) is a device that discharges drainage (condensation water) from the steam environment without leaking water vapor as much as possible and allows water vapor to pass. The steam generator 81 replenishes water vapor when the water vapor taken out from the chamber 62 and passed through the first steam trap 861 is small. The heating unit 82 heats the water vapor (the water vapor taken out from the chamber 62 and the water vapor from the steam generator 81 replenished as needed) to a predetermined temperature. The blower 83 allows the heated water vapor to pass through the third pipe 853 and the second pipe 852 and send it to the supply port 741 of the spraying unit 7. The second steam trap 862 is, for example, arranged at the outlet of the blower 83. The second steam trap 862 allows the water vapor sent from the blower 83 to pass through the second pipe 852 without condensed water. The temperature sensor 87 and the humidity sensor 88 are, for example, provided in the pipe in the path of the third pipe 853 between the blower 83 and the spraying unit 7. The supply control unit 84 controls the amount of water vapor replenished by the steam generator 81, the water vapor heating temperature by the heating unit 82, the water vapor injection pressure by the blower 83, etc. based on the measurement information of the temperature sensor 87 and the humidity sensor 88.

[0105] A method of humidifying the film material 1 using the humidifying device D will be described. However, the present invention is not limited to the case where the film material 1 is humidified using the humidifying device D.

[0106] In the chamber 62, the ambient pressure is adjusted to be substantially the same as the pressure outside the chamber 62 or slightly higher than the pressure outside the chamber 62. By adjusting the ambient pressure of the chamber 62 to be equal to or positively pressured compared to the pressure outside the chamber 62, it is possible to prevent the air outside the chamber 62 from invading the chamber 62 from the inlet 621 or the like. The ambient pressure of the chamber 62 can be adjusted by the pressure adjustment mechanism 64. In detail, the pressure adjustment mechanism 64 measures the ambient pressure inside the chamber 62, determines the difference between the ambient pressure inside the chamber 62 and the set pressure (the set pressure is equal to the pressure outside or positively pressured compared to the outside), and operates the intake and exhaust volume to adjust to the desired ambient pressure.

[0107] Furthermore, in the chamber 62, the ambient temperature is adjusted to a range of not less than the water vapor temperature -5°C and not more than the water vapor temperature +20°C. The water vapor temperature -5°C means 5°C lower than the water vapor temperature sprayed onto the film raw material 1, and the water vapor temperature +20°C means 20°C higher than the sprayed water vapor temperature. Preferably, the ambient temperature of the chamber 62 is adjusted to a range of not less than the water vapor temperature and not more than the water vapor temperature +10°C. By adjusting the ambient temperature of the chamber 62 to not less than the water vapor temperature -5°C, condensation of the film raw material 1 can be prevented. By adjusting the ambient temperature of the chamber 62 to not more than the water vapor temperature +20°C, a decrease in optical properties can be suppressed, and moisture absorbed by the film raw material 1 can be prevented from escaping from the film raw material 1.

[0108] The ambient temperature in the chamber 62 can be adjusted by the temperature adjustment mechanism 65. Specifically, the temperature adjustment mechanism 65 measures the ambient temperature in the chamber 62 and controls the heat source heater by a temperature regulator to achieve a desired ambient temperature.

[0109] Water vapor is sprayed from the discharge hole 721 of the spraying part 7 toward the film material 1. It should be noted that the water vapor is a gas containing water vapor, for example, a gas consisting of only water vapor, or a gas containing water vapor and the atmosphere.

[0110] The temperature of the water vapor sprayed to the film material 1 is 35° C. or higher, preferably 37° C. or higher, and more preferably 40° C. or higher. By using water vapor at 35° C. or higher, the polarizer of the film material 1 can quickly absorb water. The upper limit of the water vapor temperature is not particularly limited. When the upper limit of the temperature is too high, there is a risk of thermal damage to the film material 1. Therefore, for example, the upper limit of the temperature is 80° C. or lower, preferably 70° C. or lower.

[0111] Furthermore, the humidity (relative humidity %RH) of the water vapor sprayed to the film raw material is 80%RH or more, preferably 95%RH or more, and more preferably 98%RH or more. By using water vapor of 80%RH or more, the polarizer of the film raw material 1 can quickly absorb moisture. The upper limit of the water vapor humidity is 100%RH or less, preferably 95%RH or less.

[0112] Furthermore, the pressure of the water vapor sprayed to the film raw material is 0.5 kPa or more, preferably 1.0 kPa or more, and more preferably 1.5 kPa or more. By spraying water vapor with a spray pressure of 0.5 kPa or more to the film raw material 1, the polarizer of the film raw material 1 can quickly absorb water. The upper limit of the water vapor pressure is not particularly limited. When the upper limit of the water vapor pressure is too high, there is a risk of the film raw material 1 breaking. From this point of view, the water vapor pressure is, for example, 4.0 kPa or less, preferably 3.0 kPa or less.

[0113] However, the temperature and humidity of the water vapor are values ​​measured on one side of the film material 1 (the one side of the film material 1 is a portion where the water vapor ejected from the ejection holes 721 collides with the film material 1 ).

[0114] The water vapor pressure is a value obtained by the difference between the pressure measured near one surface of the thin film material 1 and the pressure outside the chamber (atmospheric pressure).

[0115] The water vapor having the above-mentioned temperature, humidity and pressure can be supplied to the spraying section 7 by a supply mechanism.

[0116] In detail, the supply control unit 84 operates the blower 83. By the operation of the blower 83, the water vapor in the chamber 62 enters the first steam trap 861 through the first pipe 851, and the condensed water is removed in the steam trap 861. In particular, when the ambient temperature in the chamber 62 is higher than the temperature of the water vapor sprayed to the film material 1, part of the water vapor taken out from the chamber 62 tends to condense easily. By arranging the first steam trap 861 near the water vapor removal port of the chamber 62, it is possible to transport only the water vapor to the spraying unit 7 via the blower.

[0117] The water vapor that has passed through the first steam trap 861 passes through the third pipe 853 and is sucked by the blower 83. When only the water vapor taken out from the chamber 62 has a low humidity, the supply control unit 84 operates the steam generator 81 and replenishes the water vapor to the third pipe 853. The replenished water vapor and the water vapor taken out from the chamber 62 merge in the third pipe 853. By taking out the water vapor in the chamber 62 and reusing it, the water vapor can be effectively used, and further, the humidifier D can be operated stably.

[0118] The supply control unit 84 operates the heating unit 82 and heats the water vapor flowing in the third pipe 853 to a predetermined temperature. The heated water vapor is transported to the shell 731 of the spraying unit 7 through the second pipe 852 and the supply port 741 by the blower 83, and is ejected from the discharge hole 721 of the arc-shaped surface 711. The supply control unit 84 controls the heating of the heating unit 82 according to the temperature measurement information of the temperature sensor 87, and adjusts the water vapor coming out of the discharge hole 721 to the above temperature. In addition, the supply control unit 84 controls the water vapor replenishment amount of the steam generator 81 according to the humidity measurement information of the humidity sensor 88, and adjusts the water vapor coming out of the discharge hole 721 to the above humidity. It should be noted that the water vapor pressure is difficult to change greatly during the operation of the humidifier D, so it is sufficient to set the blower so that the water vapor pressure becomes the above pressure from the beginning. However, a sensor such as a flow meter can also be set in the third pipe 853. The supply control unit 84 may control the strength of the blower 83 based on the measurement information of the sensor to adjust the water vapor discharged from the discharge hole 721 to the above-mentioned pressure.

[0119] It should be noted that, by using the test operation of the humidifier D, data related to the water vapor temperature, humidity and / or pressure changes during the operation of the humidifier D can be obtained. The supply control unit 84 programmed based on the data can control the heating unit 82 and the like to adjust the water vapor temperature, pressure, etc. In this case, the temperature sensor 87, humidity sensor 88, etc. can be omitted.

[0120] A long strip of film material 1 is introduced into the chamber 62. The film material 1 introduced into the chamber 62 from the carrying inlet 621 of the chamber 62 is transported along the arc-shaped surface 711 of the blowing part 7 that sprays water vapor, and is transported out of the chamber 62 from the carrying outlet 622. The transport speed of the film material 1 is not particularly limited, and for example, it can be 2 m / min to 35 m / min.

[0121] Before spraying the water vapor onto the film material 1, the film material 1 is preferably transported in the chamber 62 for more than 3 seconds. That is, preferably, the time (hereinafter referred to as the curing time) for the film material 1 entering the chamber 62 to reach the position X where the water vapor spraying starts (hereinafter referred to as the spraying start point X) is more than 3 seconds. The curing time may be more preferably more than 5 seconds, and may be further preferably more than 10 seconds.

[0122] The curing time can be measured, for example, by adding a mark to a portion of the transported film material 1 and measuring the time from the time when the mark passes through the transport inlet 621 to the time when it passes through the spraying start point X. By transporting the film material 1 for the curing time in the chamber 62 where the temperature of the sprayed water vapor is adjusted to be above -5°C, condensation on the film material 1 can be effectively prevented.

[0123] The path length of the film material 1 from the transport inlet 621 to the spraying start point X can be obtained from the curing time and the transport speed of the film material 1. It should be noted that in this specification, the path length is the transport length of the film material from one position to another.

[0124] like Figure 6 as well as Figure 8 As shown, while the film material 1 is being transported along the arc-shaped surface 711, water vapor is sprayed from the discharge hole 721 of the arc-shaped surface 711 toward one side of the film material 1. It should be noted that Figure 6 as well as Figure 8 The thin arrow in the figure indicates the direction of the water vapor ejection (hereinafter, the thin arrows shown in other figures are the same). By spraying water vapor onto the film material 1, the polarizer can absorb water. Figure 8 In the example, the film raw material 1 is shown as having Figure 2 In the case of a laminate of the first film 31 / polarizer 2 / second film 32 as shown in FIG. 1 , when the moisture permeability of the first film 31 is higher than that of the second film 32, as shown in FIG. Figure 8 As shown, the water vapor is preferably sprayed from the side of the first film 31. By spraying water vapor from the side of the first film 31 having high moisture permeability, the polarizing plate can effectively absorb moisture.

[0125] It should be noted that Figure 3 or Figure 4 When the film material 1 having the layer structure shown is humidified, water vapor can be sprayed from the polarizer 2 side of the film material 1 to allow the polarizer 2 to directly absorb water.

[0126] The film material 1 is conveyed in the chamber 62 in a state where a predetermined tension is applied. The tension applied to the film material 1 is not particularly limited, and for example, may be in a range of 50 N / m to 300 N / m, and preferably in a range of 100 N / m to 200 N / m. The film material 1, which is in a tensioned state by the tension, is conveyed while being bent along the arc-shaped surface 711 into an arc-shaped shape when viewed from the side. While the film material 1 is being conveyed along the arc-shaped surface 711 of the blowing section 7, the tension of the film material 1 and the blowing pressure of the water vapor balance each other, and the film material 1 leaves the arc-shaped surface 711 and is conveyed along the arc-shaped surface 711. In this way, the tension and the blowing pressure balance each other, and the film material 1 is bent into an arc shape, whereby the film material 1 is conveyed at a substantially constant distance L (the symbol L representing the distance refers to FIG. 1 ) from the arc-shaped surface 711. Figure 8 ) is transported along the arc surface. Therefore, the water vapor from the ejection hole 721 of the arc surface portion 711 can be sprayed almost evenly toward one side of the film material 1, and the polarizing plate can effectively absorb moisture.

[0127] According to the present invention, since the polarizer can effectively absorb moisture, the humidification treatment of the film material 1 can be completed in a shorter time. For example, the time for spraying water vapor to the film material 1 (hereinafter referred to as the spraying time) can be more than 10 seconds and less than 90 seconds, preferably more than 30 seconds and less than 60 seconds.

[0128] The spraying time is referred to as the transport time of the film material 1 from the spraying start point X to the position Y where the spraying of water vapor ends (the spraying end point Y). The spraying time can be measured, for example, by adding a mark to a portion of the film material 1 being transported and measuring the time from the time when the mark passes through the spraying start point X to the time when the mark passes through the spraying end point Y. In addition, the path length of the film material 1 from the spraying start point X to the spraying end point Y can be obtained from the spraying time and the transport speed of the film material 1.

[0129] By performing the above-mentioned humidification treatment on the film raw material 1, a humidity-controlled optical film 1a is obtained. The film raw material 1 (optical film 1a) that has passed the spraying end point Y is transported from the transport outlet 622 to the outside of the chamber 62. The obtained optical film 1a is rolled up by the winding device E. It should be noted that, as required, the optical film 1a can also be subjected to any appropriate treatment after the humidification treatment and before being rolled up by the winding device E.

[0130] Other embodiments of the present invention are described below. However, there is a situation where the description mainly describes the configuration and effects that are different from the above-mentioned embodiments, and for the same configuration, the description of the configuration can be omitted by directly quoting the words or figure marks.

[0131] [Second embodiment]

[0132] The humidifier D of the first embodiment includes the spray portion 7 having the arc-shaped surface portion 711 , but the spray portion 7 is not limited thereto and various design changes may be made.

[0133] Fig.11 is a side view showing in detail the humidifying device D according to the second embodiment, and Figure 6 Likewise, the chamber 62 and a portion of the conduit are shown in cross-section. Fig.12 This is a cross section of the spraying unit 7 and the film material 1 of the humidifying device D according to the second embodiment cut along the conveying direction. Fig.13 2 is a reference perspective view showing a state where the film material 1 is conveyed along the blowing section 7 in the humidifying device D according to the second embodiment. Fig.13 In FIG. 1 , the film material 1 is indicated by an imaginary line (two-dot chain line).

[0134] exist Figures 11 to 13 In the embodiment, the blowing part 7 of the humidifying device D has a slit-shaped discharge hole 722. Specifically, the blowing part 7 has a hollow shell 732 and a supply port 742, wherein the shell 732 has a flat surface 712 formed with a plurality of discharge holes 722, and the supply port 742 supplies water vapor into the shell 732. The flat surface 712 is linear when viewed from the side.

[0135] The ejection hole 722 formed in the flat surface 712 may be, for example, an elongated slit-shaped opening when viewed from above. In the illustrated example, the ejection hole 722 is an elongated slit-shaped opening extending in the width direction of the film material 1 ( Fig.13 reference).

[0136] The size of the ejection hole 722 is not particularly limited, but if it is too small, there is a risk of clogging, and if it is too large, there is a risk of deviation in the pressure of water vapor. From this point of view, the width of the ejection hole 722 can be, for example, 0.8 mm to 5.0 mm, preferably 2 mm to 4 mm. The number of ejection holes 722 formed per unit area is not particularly limited, and the size of the ejection hole 722 can be appropriately set in consideration. For example, the size and number of the ejection holes 722 are set in a manner such that the opening rate is in the range of 0.2% to 5.0%, preferably in the range of 0.5% to 3.0%. Here, the opening rate is the ratio of the total opening area of ​​the ejection holes 722 per unit area of ​​the flat surface 712 facing the film raw material 1, and is obtained by the formula: (total opening area of ​​the ejection holes 722 / unit area of ​​the flat surface 712 of the blowing section 7) × 100%.

[0137] Each of the ejection holes 722 is formed in the flat surface 712 so as to eject the water vapor in the vertical direction of the flat surface 712. By ejecting the water vapor from each of the ejection holes 722 in the vertical direction of the flat surface 712, the water vapor can be ejected in a substantially vertical direction relative to one side of the film material 1 (the water vapor is ejected in a substantially thickness direction of the film material 1).

[0138] It should be noted that conveyance nip rollers 624 are arranged on the upstream and downstream sides of the blowing section 7 so that the film material is not tilted by the blown water vapor.

[0139] The other configurations of the humidifier D of the second embodiment can be the same as those of the first embodiment.

[0140] As with the first embodiment, the humidifying device D of this embodiment also transports the film raw material 1 into the chamber 62 adjusted to a predetermined ambient temperature, and in the blowing section 7, water vapor at a temperature of 35° C. or higher and 80% RH or higher and a blowing pressure of 0.5 kPa or higher is blown toward the film raw material 1. In this embodiment, the humidification treatment of the polarizer can be completed in a relatively short time, and a humidified optical film 1a containing an appropriate amount of water can be obtained.

[0141] [Modification of Second Embodiment]

[0142] The ejection hole 722 of the second embodiment is in the form of a long and narrow slit extending in the width direction of the film material 1, but is not limited thereto. Fig.14 As shown, the discharge hole 722 may be a slit-shaped elongated slit extending in the conveying direction of the film material 1. Also, although not particularly shown, the slit-shaped discharge hole 722 may be formed to extend in a direction inclined with respect to the conveying direction of the film material 1.

[0143] Furthermore, in the above-mentioned embodiment, water vapor is sprayed only from one side of the film material 1, but water vapor may be sprayed from one side and the opposite side of the film material 1. Fig.15 As shown, by arranging the blowing section 7 on one side of the film material 1 conveyed into the chamber 62 and arranging the blowing section 7 on the opposite side of the film material 1 , water vapor can be sprayed from both sides of the film material 1 .

[0144] [Third Embodiment]

[0145] Fig.16 1 is a reference plan view showing a state where the film material 1 is conveyed along the blowing section 7 in the humidifying device D according to the third embodiment. Fig.16 In FIG. 1 , the film material 1 is indicated by an imaginary line (two-dot chain line).

[0146] exist Fig.16 In the embodiment, the blowing part 7 of the humidifying device D of this embodiment has a flat surface 713 formed with a dot-shaped discharge hole 723. Specifically, the blowing part 7 has a hollow shell 733 and a supply port 743, wherein the shell 733 has a flat surface 713 formed with a plurality of dot-shaped discharge holes 723, and the supply port 743 supplies water vapor into the shell 733. The flat surface 713 is linear when viewed from the side, similarly to the flat surface 712 of the second embodiment. In addition, the blowing part 7 of the third embodiment is substantially the same as the second embodiment except for the discharge hole 723.

[0147] The discharge hole 723 formed in the flat surface 713 is, for example, a substantially circular opening in a plan view. The dot-shaped discharge hole 723 is not limited to a substantially circular opening, and may also be a substantially quadrilateral opening in a plan view. Fig.16 In the embodiment, the configuration of the plurality of dot-shaped discharge holes 723 is set to a staggered configuration. The configuration of the discharge holes 723 is not limited to a staggered configuration, and may also be a grid configuration, or may be other configurations. The shape, size, number of formations, and opening ratio of the discharge holes 723 of the third embodiment may also be applied to the shape of the discharge holes 721 of the first embodiment.

[0148] Each of the ejection holes 723 is formed in the flat surface 713 to eject the water vapor in the vertical direction of the flat surface 713. By ejecting the water vapor from each of the ejection holes 723 in the vertical direction of the flat surface 713, the water vapor can be ejected in a substantially vertical direction relative to one side of the film material 1.

[0149] In order to prevent the film material from being tilted, transport nip rollers (not shown) are arranged on the upstream and downstream sides of the blowing section 7 of the third embodiment, similarly to the second embodiment.

[0150] The other configurations of the humidifier D according to the third embodiment can be the same as those of the first embodiment.

[0151] In the humidifying device D of the third embodiment, similarly to the first embodiment, the film raw material 1 is transported in the chamber 62 adjusted to a predetermined ambient temperature, and water vapor at a temperature of 35° C. or higher and 80% RH or higher and a pressure of 0.5 kPa or higher is sprayed on the film raw material 1 in the spraying section 7. In this embodiment, the humidification treatment of the polarizer can be completed in a relatively short time, and a humidified optical film 1a containing an appropriate amount of water can be obtained.

[0152] [Fourth embodiment]

[0153] In each of the above-mentioned embodiments, the film raw material after laminating the first film and / or the second film on the polarizer is humidified, but the polarizer may be humidified as the film raw material and the first film and / or the second film may be laminated on the humidified film raw material (polarizer) (not shown).

[0154] [Applications of optical films, etc.]

[0155] The use of the optical film including the polarizing plate of the present invention is not particularly limited. Since the optical film of the present invention is unlikely to bend and deform over time, it can be suitably used as an optical film for displays such as liquid crystal display devices and organic display devices.

[0156] Furthermore, the optical film of the present invention is not limited to being used in the aforementioned display, and can also be used for purposes other than displays. As purposes other than displays, optical equipment, buildings, medical and food fields, etc. can be listed. When the optical film is used in optical equipment, the optical film can be processed by, for example, a polarizer, a transparent radio wave blocking film, etc. When the optical film is used in electronic equipment, the optical film can be processed by, for example, a dimming window film, etc. When the optical film is used in the medical and food fields, the optical film can be processed by, for example, a light-degradation prevention film, etc.

[0157] [Example]

[0158] Hereinafter, the present invention will be described in further detail by showing examples and comparative examples. However, the present invention is not limited to the following examples.

[0159] [Film materials used]

[0160] A long strip of film raw material can be used in which a 40 μm thick triacetyl cellulose (TAC) film (KC4CT, Konica Minolta Corporation) is laminated on one side of an 18 μm thick polarizer (VF-PE#4500, manufactured by Kuraray Co., Ltd.) via an adhesive, and a 40 μm thick cyclic olefin (COP) film (ZEONOR Film ZF-16, manufactured by Zeonor Co., Ltd.) is laminated on the opposite side of the polarizer via an adhesive.

[0161] The moisture permeability of the TAC film is 620g / m 2 ·After 24 hours, the moisture permeability of COP film is 1.2g / m 2 ·24h. Moisture permeability is measured by JIS Z0208-1976 (aluminum cup method) at a temperature of 65°C and a relative humidity difference of 90%.

[0162] [Humidifier]

[0163] Prepared as Figures 6 to 9 As shown, a humidifying device D is provided with a blowing portion 7 having an arc-shaped surface portion 711 in which a plurality of discharge holes 721 are formed.

[0164] The discharge hole 721 is a circle with a diameter of 400 mm and an opening ratio of 1.0%.

[0165] [Method for measuring temperature, humidity and pressure of water vapor]

[0166] The temperature and humidity of the water vapor were measured near the outlet of the discharge hole of the spraying part. The temperature and humidity of the water vapor were measured using a trade name "HM70 Hygrothermometer" manufactured by VAISALA.

[0167] The difference between the pressure measured near the outlet of the ejection hole of the blowing part (approximately the same as near one side of the film raw material) and the pressure outside the chamber (atmospheric pressure) is taken as the pressure of the water vapor. The pressure near the ejection hole of the blowing part is measured using a "Mano Star Gauge" manufactured by Yamamoto Electric Manufacturing Co., Ltd.

[0168] However, the temperature, humidity and pressure of water vapor were measured approximately 30 minutes after the start of operation (after the operation stabilized).

[0169] [Method for measuring ambient temperature and humidity in the chamber]

[0170] The measurement was performed using a temperature sensor and a humidity sensor placed in the chamber.

[0171] However, the temperature and humidity in the chamber were measured approximately 30 minutes after the start of operation (after the operation stabilized).

[0172] [Method for measuring the increase in absorbance]

[0173] The absorbance was measured using a product name "RX200" manufactured by Kurabo Industries, Ltd.

[0174] The absorbance of the film raw material before the humidification treatment was measured, and further, the absorbance after the humidification treatment was measured, and the increase in absorbance was calculated according to the following formula.

[0175] Formula: Increase in absorbance = absorbance after humidification - absorbance before humidification.

[0176] [Example 1]

[0177] Under the humidification conditions shown below, the film raw material was conveyed in the chamber of the humidification device to be humidified. It should be noted that the film raw material was conveyed so that water vapor was directly sprayed toward the TAC film side.

[0178] <Humidification conditions>

[0179] The temperature of the steam from the outlet of the blowing part is 35°C.

[0180] The humidity of the water vapor coming out from the outlet of the blowing part is 80%RH.

[0181] The pressure of the water vapor coming out from the discharge hole of the blowing part is 0.8 kPa.

[0182] Ambient temperature in the chamber: 32°C.

[0183] Ambient humidity in the chamber: 70%RH.

[0184] Curing time: about 10 seconds.

[0185] Blowing time: about 15 seconds.

[0186] The conveying speed of the film material is 3m / min.

[0187] In order to confirm the degree of increase in the water content of the thin film raw material after the humidification treatment obtained in Example 1, the increase in absorbance was measured. The results are shown in Table 1.

[0188] The appearance of the film material after the humidification treatment was visually observed. The results are shown in Table 1.

[0189] However, "A" in the column of appearance in Table 1 indicates that condensation water does not adhere to the film material, "B" indicates that condensation water adheres to a portion of the film material, and "C" indicates that condensation water adheres to substantially the entire film material.

[0190] Table 1

[0191]

[0192] [Examples 2 to 7, Comparative Examples 1 and 2]

[0193] The film raw material was humidified in the same manner as in Example 1 except that the humidification conditions were changed to those shown in Table 1.

[0194] In Examples 2 to 7 and Comparative Examples 1 and 2, the increase in absorbance of the film raw material was measured and the appearance after the humidification treatment was observed in the same manner as in Example 1. These results are shown in Table 1.

[0195] [Comparative Example 3]

[0196] The film raw material was humidified in the same manner as in Example 1 except that the film raw material was conveyed in a chamber without a water vapor blowing section and subjected to humidification treatment. That is, the film raw material was humidified by conveying the film raw material in a chamber at a temperature and humidity shown in Table 1 without spraying water vapor from the blowing section.

[0197] In Comparative Example 3, the increase in absorbance of the film raw material was measured in the same manner as in Example 1, and the appearance after the humidification treatment was observed.

[0198] [evaluate]

[0199] It can be seen that Examples 1 to 7 can make the film raw material contain a sufficient amount of water while having the same spraying time as Comparative Examples 1 and 2. It can be seen that in Comparative Example 1, where the water vapor pressure is 0.45 kPa, the spraying time must be increased in order to make it contain a sufficient amount of water. In addition, it can be seen that in Comparative Example 2, where the water vapor temperature is 30°C and the humidity is 70%RH, the spraying time must be increased in order to make it contain a sufficient amount of water.

[0200] Furthermore, it can be seen that Examples 4 to 7 in which the humidity of the water vapor is 95% RH have a better effect of causing the film raw material to contain moisture than Examples 1 to 3 in which the humidity of the water vapor is 80% RH.

[0201] Description of Reference Numerals

[0202] 1 Film raw materials

[0203] 1a Optical Film

[0204] 2 Polarizer

[0205] 31 First Film

[0206] 32 Second Film

[0207] 62 Chamber

[0208] 7 Blowing Section

[0209] 711 Arc Face

[0210] 721, 722, 723 Water vapor outlet

[0211] A. Optical thin film manufacturing device

[0212] B Polarizing plate manufacturing device

[0213] C stacking device

[0214] D Humidifier

Claims

1. A method for producing an optical film, by humidifying the film raw material containing a polarizing plate, the moisture-regulated optical film is characterized in that The film raw material with the polarizing plate was sprayed with a water vapor of 35°C or more and 80% RH or more at a pressure of 0.5 kPa or more.

2. The method for producing an optical film according to claim 1, wherein: The polarizing plate is a dyed and stretched hydrophilic polymer film.

3. The method for producing an optical film according to claim 1 or 2, characterized in that: The film raw material includes the polarizing plate and a protective film laminated on the polarizing plate.

4. The method for producing an optical film according to claim 1 or 2, characterized in that: The time for the film raw material to be sprayed with the pressure water vapor is 10 seconds or more.

5. The method for producing an optical film according to claim 1 or 2, characterized in that: The film raw material is directed into a chamber adjusted to a predetermined ambient temperature, In the chamber, during transport of the film feedstock, the pressure of water vapor is blown to the film feedstock.

6. The method for manufacturing an optical film according to claim 5, characterized in that: The ambient temperature in the chamber is a range from a temperature of -5°C or more and a temperature of +20°C or less.

7. The method for producing an optical film according to claim 6, wherein: The film raw material is transported in the chamber for more than 3 seconds before the water vapor is sprayed into the film raw material.

8. The method of manufacturing an optical film according to claim 5, characterized in that A blowing part having an arc-shaped surface is arranged in the chamber, and a plurality of discharge holes are formed on the arc-shaped surface. While the film material is being conveyed along the arc-shaped surface in a tensioned state, the water vapor is sprayed toward the film material from the discharge hole, so that the tension of the film material and the blowing pressure of the water vapor balance each other, and the film material leaves the arc-shaped surface and is conveyed along the arc-shaped surface.

9. The method of manufacturing an optical film according to claim 5, characterized in that A blowing part having a flat face is arranged in the chamber, and a plurality of dot-shaped discharge holes are formed on the flat face. During transporting the film raw material along the blowing portion in a tensioned state, the water vapor is sprayed vertically from the discharge hole with respect to one side of the film raw material.

10. The method for manufacturing an optical film according to claim 1 or 2, characterized in that The film raw material includes the polarizing plate, the first film and the second film respectively laminated on one side of the polarizing plate and the opposite side thereof. The moisture permeability of the first film is higher than the moisture permeability of the second film, The water vapor is sprayed from at least the first film side.

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