KR102637761B1 - Package, storage or transport method for polyvinyl alcohol-based film, polyvinyl alcohol-based film, and polarizing film - Google Patents

Abstract

Provided is a polyvinyl alcohol-based film packaging body that can suppress deformation and deterioration of optical performance even during storage or transportation. The package 11 is made of a film roll 3 by wrapping a strip-shaped polyvinyl alcohol-based film around a core pipe 2, and protective pads 7 are attached to both ends of the film roll 3, respectively, for protection. This is achieved by wrapping the film roll (3) together with the pad (7) with a water vapor barrier film (4). A humidity control sheet 8 is attached to the protection pad 7 on the contact surface with the film roll 3, so the film roll 3 acts as a water vapor barrier together with the protection pad 7 to which the humidity control sheet 8 is attached. It is packaged with film (4). By packaging the humidity control sheet 8 together with the film roll 3 in this way, the humidity of the internal space where the film roll 3 is placed is controlled to 20 to 80%RH.

Description

Package, storage or transport method for polyvinyl alcohol-based film, polyvinyl alcohol-based film, and polarizing film

The present invention relates to a packaging body, a method of storing or transporting a polyvinyl alcohol-based film, a polyvinyl alcohol-based film, and a polarizing film. More specifically, the present invention provides a packaging body that is very suitable for storage or transportation of a polyvinyl alcohol-based film that has an excellent appearance and is free from optical stains and is useful as a raw material for obtaining a polarizing film, and a packaging body using the same to store or transport a polyvinyl alcohol-based film It relates to a transport method, a polyvinyl alcohol-based film stored and/or transported in this way, and a polarizing film manufactured using this polyvinyl alcohol-based film.

Conventionally, a polyvinyl alcohol-based film is made by dissolving a polyvinyl alcohol-based resin in a solvent such as water, forming it into a film using a solution casting method (casting method), and then using a metal heating roll (hereinafter referred to as a metal heating roll). It is manufactured by using and drying. The polyvinyl alcohol-based film produced in this way is a film with excellent transparency and dyeing properties and is used in many applications. One useful application is a polarizing film.

The polarizing film is a film obtained by dyeing the above polyvinyl alcohol-based film with a dye, and is used as a basic component of a liquid crystal display. Recently, it has been used in displays that require high quality and high reliability, especially large-screen liquid crystal TV sets, and further reduction of in-plane polarization uniformity and color unevenness is required.

In order to meet such demands, it is necessary to improve the physical properties of the polyvinyl alcohol-based film itself, but the packaging form during storage or transportation of the polyvinyl alcohol-based film after production is also important. This is because, if the moisture content of the polyvinyl alcohol-based film changes significantly during storage or transportation, or if the moisture content within the film plane becomes uneven, not only will the film be deformed, but the optical properties within the film plane will change, and the polarization degree of the resulting polarizing film will change. This is because spots (in-plane non-uniformity of polarization) or color unevenness occur.

As a technology to solve this problem, for example, in Patent Document 1, a technology for storing or transporting a roll of polyvinyl alcohol-based film by packaging it with a packaging film made of a vapor barrier resin packaging film and an aluminum material is proposed. There is (see paragraphs 0042 to 0044). Also, for example, Patent Document 2 proposes a package in which both ends of the packaging material are fixed to the core pipe, and then the excess portions of both ends are pushed into the core pipe (see paragraph 0014 and FIG. 3).

Patent Document 1 JP 2005-306483 A Patent Document 2 JP 2013-227073 A

However, even with the above disclosed technology, it is insufficient to suppress deformation of the polyvinyl alcohol-based film and deterioration of optical performance during transportation.

Generally, polyvinyl alcohol-based films are packaged with a moisture content of several percent. Even if moisture is prevented from entering from the outside by a vapor barrier resin packaging film, if moisture enters the inside of the package from the gap between the packaging film and the core pipe, deformation or optical staining will occur. In addition, if moisture absorption and desorption are repeated inside the package due to the moisture of the film itself, deformation or optical stains may occur. This phenomenon is more likely to occur as the polyvinyl alcohol-based film becomes significantly longer, and becomes more noticeable as it becomes thinner.

Therefore, the problem to be solved by the present invention is to provide a package of polyvinyl alcohol-based film that can reduce the occurrence of deformation and optical stains even during storage or transportation.

Therefore, as a result of diligent research by the present inventors to solve the above problem, they discovered that the above problem can be solved by controlling the humidity of the space inside the package to 20 to 80%RH. The invention was completed.

That is, the present invention is a package made by wrapping a film roll of a strip-shaped polyvinyl alcohol-based film wound around a core pipe with a vapor barrier film,

This package is characterized in that the humidity of the space inside the package is controlled to 20-80%RH.

In addition, it is preferable that the above packaged body is packaged with a humidity control sheet together with the above film roll.

Additionally, the humidity control sheet is preferably made of non-woven fabric with a thickness of 0.1 to 2 mm.

Moreover, it is preferable that the moisture absorption rate of the humidity control sheet at 30°C and 90%RH is 50% by weight or more.

The axial length of the core pipe is longer than the film width, and the end of the core pipe in the water vapor barrier film on the axial direction side is folded into the interior of the core pipe protruding from the film roll to surround the end of the core pipe. It is preferable that the core pipe is wound and an absorbent material is disposed inside the core pipe.

In addition, it is preferable that the above-mentioned package has a humidity indicator packaged together with the above-mentioned film roll.

The polyvinyl alcohol-based film is preferably 4 m or more in width and 4 km or more in length.

The thickness of the polyvinyl alcohol-based film is preferably 5 to 40 μm.

It is preferable that the polyvinyl alcohol-based film is a polyvinyl alcohol-based film for a polarizing film.

Additionally, the present invention is a method of storing or transporting a polyvinyl alcohol-based film, characterized in that the polyvinyl alcohol-based film is stored and/or transported using the packaging body.

Additionally, the present invention is a polyvinyl alcohol-based film characterized in that it is stored and/or transported using the above packaging.

Additionally, the present invention is a polarizing film manufactured using the above-mentioned polyvinyl alcohol-based film.

According to the present invention, deformation and deterioration of optical performance during storage and/or transportation of a strip-shaped polyvinyl alcohol-based film are suppressed, and deterioration of the film due to film roll misalignment, scratches, and blocking is prevented. can do. Additionally, the quality of the film roll in the width direction or longitudinal direction (from the outer periphery of the roll to the core portion) can be kept constant. In addition, a polarizing film with excellent in-plane uniformity can be obtained, and productivity can be increased by facilitating unwinding during the production of the polarizing film.

1 is a schematic cross-sectional view showing an enlarged portion of a package 11 according to the first embodiment of the present invention.
FIG. 2 is a perspective view showing the packaging sequence of the film roll 3 in the package 11.
Fig. 3 is a schematic cross-sectional view showing an enlarged portion of a package 21 according to the second embodiment of the present invention.
FIG. 4 is a perspective view showing the packaging sequence of the film roll 3 in the package 21.
Fig. 5 is an enlarged schematic cross-sectional view showing a part of the package 101 in the second embodiment when the absorbent material 6 is not disposed.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention will be described in detail with reference to the drawings. In addition, hereinafter, the same or equivalent elements are given the same reference numerals throughout all drawings, and overlapping descriptions thereof are omitted.

The package of the present invention is a package made by packaging a film roll with a strip-shaped polyvinyl alcohol-based film wound around a core pipe with a vapor barrier film, and the humidity of the inner space of the package where the film roll is placed is 20 to 80%RH. It is characterized by controlled humidity.

The humidity of the internal space of the package is preferably 30 to 70%RH, particularly preferably 35 to 65%RH. If the humidity is too low or too high, the polyvinyl alcohol-based film on the surface of the film roll tends to dry/absorb moisture and deform, and if the humidity is too low or too high and changes several times, the polyvinyl alcohol film The appearance and optical performance of the based film tend to deteriorate. Specifically, white haze may occur or optical staining may increase.

FIG. 1 is a schematic cross-sectional view showing an enlarged portion of a package 11 according to the first embodiment of the present invention, and FIG. 2 is a perspective view showing the packaging sequence of the film roll 3 in the package 11.

As shown in FIG. 2, the package 11 forms a film roll 3 by winding a strip-shaped polyvinyl alcohol-based film around a core pipe 2 whose axial length is longer than the film width. This is done by attaching protective pads (7) to both ends, and then wrapping the film roll (3) with the protective pads (7) with a vapor barrier film (4).

More specifically, as shown in Fig. 2(a), one end of the rectangular water vapor barrier film 4 is fixed at a predetermined winding start position on the outer periphery of the film roll 3. At this time, one side of the vapor barrier film (4) is arranged and fixed so that it is parallel to the axis direction of the core pipe (2).

Next, as shown in FIG. 2(b), after wrapping the water vapor barrier film 4 at least once along the outer periphery of the film roll 3, the other end of the water vapor barrier film 4 is wrapped, for example, with adhesive tape 5. ) to fix it. At this stage, the water vapor barrier film 4 is cylindrical. Thereafter, as shown in FIG. 2(c), the two ends of the water vapor barrier film 4 on the axial direction side of the core pipe 2 are connected to the film roll 3 (strictly as shown in FIG. 1). Likewise, each of the core pipes 2 protruding from the protection pad 7 is fixed to the outer peripheral portion thereof to complete the package 11 of the present embodiment.

Methods for fixing the end of the water vapor barrier film 4 and the outer periphery of the core pipe 2 include, for example, a method of wrapping a tape around the outside of the water vapor barrier film 4, a method of fixing with a double-sided adhesive tape, Examples include a method of fixing the end of the water vapor barrier film 4 to the outer surface of the adhesive tape attached to the outer periphery of the core pipe 2 with a heat seal, a method of using a rubber band, and a method of using a cotton fastener. Among them, a method of wrapping a tape around the outside of the water vapor barrier film 4 and fixing it, a method of fixing it with a double-sided adhesive tape, and a method of fixing the end of the water vapor barrier film 4 to the outer surface of the adhesive tape attached to the outer periphery of the core pipe 2. A method of fixing with a heat seal is preferable from the viewpoint of stably maintaining the humidity of the internal space of the package 11.

In addition, in FIG. 1, for ease of understanding, the water vapor barrier film 4 is drawn with a gap between the film roll 3 and the core pipe 2, but in reality, the water vapor barrier film 4 is a film roll ( 3) and is wound and fixed around the outer periphery of the core pipe (2) so as to be in close contact with the core pipe (2), and the film roll (3) is sealed with the water vapor barrier film (4).

In this way, in the package 11, the film roll 3 is placed in the internal space formed by the core pipe 2 and the water vapor barrier film 4. The present invention suppresses deformation and deterioration of optical performance of a strip-shaped polyvinyl alcohol-based film during storage or transportation by appropriately controlling the humidity of the internal space where the film roll 3 is disposed.

As shown in Fig. 1, a protective pad 7 is attached to the end of the film roll 3 before packaging. A humidity control sheet 8 is attached to the protection pad 7 on the contact surface with the film roll 3. Accordingly, the film roll 3 is attached with the protection pad 7 to which the humidity control sheet 8 is attached, It is packaged with a vapor barrier film (4). In this way, by packaging the humidity control sheet 8 together with the film roll 3, the humidity of the internal space of the package 11 where the film roll 3 is placed can be controlled to 20 to 80%RH. You can.

The strip-shaped polyvinyl alcohol-based film in the present invention is not particularly limited, and for example, a polyvinyl alcohol-based film manufactured by the method described later is used. The width of such a film is preferably 4 m or more from the viewpoint of increasing the area, particularly preferably 4.5 m or more from the viewpoint of newly increasing the area, and more preferably 4.5 to 6 m from the viewpoint of avoiding fracture.

The core pipe 2 wrapped with a strip-shaped polyvinyl alcohol-based film may be cylindrical in external shape, and is preferably hollow and cylindrical from the viewpoint of weight reduction. Moreover, if the core pipe 2 is cylindrical, a support bar can be inserted inside and the film roll 3 can be placed on a stand or processing device.

The material of the core pipe 2 includes metal, plastic, etc., and is not particularly limited. Examples of metals include carbon steel, high-strength steel, stainless steel, aluminum, aluminum alloys such as duralumin, copper, brass, and bronze. A resin layer of soft polyvinyl chloride or low-density polyethylene may be laminated on the surface or inner side of the metal core pipe 2, or may be plated with nickel, chromium, zinc, tin, or the like. Examples of plastic include hard polyvinyl chloride, polypropylene, high-density polyethylene, ultra-high molecular weight polyethylene, polycarbonate, and polyester.

The outer diameter of the core pipe 2 is preferably 7.5 cm or more, and particularly preferably 8.5 cm or more. If the outer diameter of the core pipe 2 is too small, wrinkles tend to occur in the film. When the core pipe 2 is cylindrical, the thickness of the core pipe 2 is preferably 1.5 to 20 mm, particularly preferably 2 to 15 mm, and still more preferably 3 to 10 mm. The size of the core pipe 2 is generally 11 to 31 cm in outer diameter and 10 to 30 cm in inner diameter.

The axial length (i.e., the length in the axial direction) of the core pipe 2 needs to be longer than the film width of the above-described strip-shaped polyvinyl alcohol-based film, and is 10 cm from both ends on the axial direction side of the film roll 3. It is desirable that it protrudes more than above. Specifically, the axial length of the core pipe 2 is preferably 4.1 m or more, particularly preferably 4.6 m or more from the viewpoint of increasing the area, and more preferably 4.6 to 4.6 m from the viewpoint of avoiding breakage of the polyvinyl alcohol-based film. It is 6.1m.

Since the core pipe 2 has a protrusion, a bracket is installed on both ends of the protrusion, or both ends of the protrusion are placed on a stand, etc., so that the film roll 3 floats in the air without contacting the ground or other film rolls, etc. This can prevent the load of the entire package 11 from being applied to the entire film roll 3, and blocking or deterioration of the films can be prevented. Additionally, a vapor barrier film 4 or a packaging film can be fixed to both ends of the protrusion.

The water vapor barrier film 4 used in the present invention is not particularly limited, but one having a moisture permeability measured in accordance with JIS Z 0208 of 10 g/m2·day or less, preferably 1 g/m2·day or less, can be used. Specific examples include single-layer films such as high-density polyethylene, low-density polyethylene, polypropylene, polyester, polyvinylidene chloride coated polypropylene, and glass-evaporated polyester, or laminated films thereof, or laminations with split fabric, paper, or non-woven fabric. Film, etc. can be mentioned. Examples of the laminated film include a laminated film of glass or aluminum evaporated polyester and polyethylene, and a laminated film of polyvinylidene chloride coated polypropylene and polyethylene.

It is also preferable that such a water vapor barrier film 4 is treated to prevent static electricity from entering, and the antistatic agent may be kneaded into the film or coated on the surface. It is preferable to use an antistatic agent in an amount of about 0.01 to 5% by weight relative to the resin in the case of including paste, and in an amount of about 0.01 to 1 g/m2 in the case of surface coating.

The antistatic agent is not particularly limited as long as it does not adversely affect optical performance, and examples include alkyldiethanolamine, polyoxyethylenealkylamine, higher fatty acid alkanol amide, and sorbitan fatty acid ester.

It is also preferable to use a laminate in which a moisture-absorbing film is laminated to a moisture-absorbing film as such a vapor barrier film 4 from the viewpoint of controlling the humidity of the internal space of the package 11. Such moisture-absorbing films include, for example, dispersing an inorganic or organic desiccant such as calcium chloride, silica gel, zeolite, saccharide, or absorbent resin into a moldable material such as synthetic resin, natural cellulose, synthetic cellulose, glass cloth, or nonwoven fabric. Examples include those that are impregnated, applied and dried to form a moisture-absorbing layer, and those in which these inorganic or organic desiccants are sandwiched between thermoplastic resin films such as polyester film, polyethylene film, polypropylene film, and Teflon (registered trademark) film. When using such a laminate, it is packaged so that the moisture-absorbing film side is inside the package 11.

Before packaging the film roll 3 with the water vapor barrier film 4, it is also possible to wrap an interior film that also serves as a protective film around the film roll 3. By winding the interior film, contamination or damage to the film roll 3 can be prevented. Such an interior film is not particularly limited, but an inexpensive polyethylene film is very suitable.

After packaging the film roll (3) with the water vapor barrier film (4), it may be packaged again with a packaging film made of aluminum. Such packaging films include aluminum foil, a laminated film of aluminum foil and a moisture-resistant plastic film (e.g., a laminated film of aluminum foil and a polyolefin film), and a laminated film of an aluminum vapor-deposited film and a moisture-resistant plastic film (e.g., A laminated film of an aluminum vapor-deposited film and a polyolefin film), a laminated film of an aluminum vapor-deposited film and a moisture-resistant plastic film (for example, a laminated film of an aluminum-evaporated polyester film and a polyethylene film), etc.

In particular, in the present invention, a laminated film of an aluminum foil and a polyolefin film (for example, a laminated film of an aluminum foil and a polyethylene film), a laminated film of an aluminum vapor-deposited film and a polyolefin film (for example, a laminated film of an aluminum foil-deposited polyester film and a polyethylene film) Laminated films) are useful, and in particular, laminated films composed of stretched polypropylene film/polyethylene film/aluminum foil/polyethylene film, laminated films composed of stretched polypropylene film/low-density polyethylene film/aluminum foil, etc. are useful. .

Additionally, the package 11 of this embodiment can be stored and/or transported by packing the entire package with an insulating material. Naturally, the humidity of the internal space of the package 11 depends on the temperature. Recently, temperatures during storage and/or transportation have been managed from a quality assurance viewpoint, but actual conditions often fluctuate in the range of 0 to 80°C. In order to adjust the humidity of the internal space of the package 11 to the above range, temperature management of the package 11 is also important. The insulating material used in the present invention is not particularly limited, but an aluminum evaporated sheet is preferable from the viewpoint of insulating properties, and an aluminum evaporated felt is particularly preferable from the viewpoint of impact resistance. Additionally, it is desirable to recycle the insulation material.

As a method of adjusting the humidity of the internal space of the package 11 to the above range, a drying sheet containing a desiccant such as silica gel, calcium chloride, or zeolite sandwiched between thermoplastic films or paper is packaged together with the film roll 3. However, in the present invention, it is preferable to package the humidity control sheet (8) together with the film roll (3). Such a humidity control sheet 8 maintains the humidity of the internal space of the package 1 constant through moisture absorption and desorption. Drying with a drying sheet alone cannot control humidity, and if the interior space of the package 11 is too dry, deformation occurs in the polyvinyl alcohol-based film. In addition, with such dry sheets, once moisture is absorbed, moisture resistance is slow, so it is difficult to respond to repeated changes in humidity. In addition, such dry sheets have a problem in that they cannot respond to rapid environmental changes because the moisture absorption amount is small and the moisture absorption rate is slow.

The humidity control sheet 8 used in the present invention is preferably made of non-woven fabric from an environmental viewpoint. Generally, inorganic desiccants are industrial waste, but nonwovens can be incinerated. More preferably, a nonwoven fabric made of highly moisture-absorbing fibers from the viewpoint of moisture absorption rate or moisture absorption rate, particularly preferably a nonwoven fabric made of acrylic high moisture-absorbing fibers from the viewpoint of repeated durability, more preferably acrylic acid polymer partially sodium salt cross-linked fiber or acrylic acid. It is a non-woven fabric made of aggregate cross-linked fibers. Examples of the acrylic acid polymer partially sodium salt cross-linked fiber include “Bell Sunny” manufactured by Teijin Limited, and examples of the acrylic acid polymer partially cross-linked fiber include “Moss Fine” manufactured by Toyobo Company Limited. Additionally, polyethylene fibers, polyester fibers, etc. may be added to the nonwoven fabric to the extent that they do not impair hygroscopicity.

The thickness of the humidity control sheet 8 is preferably 0.1 to 2 mm, particularly preferably 0.2 to 1.5 mm, and still more preferably 0.3 to 1.0 mm. If the thickness is too small, moisture absorption tends to be insufficient, and conversely, if it is too large, processing or handling tends to be difficult.

The moisture absorption rate of the humidity control sheet 8 is preferably 50% by weight or more relative to its own weight (weight in a dry state) at 30°C and 90%RH, particularly preferably 70% by weight or more, and even more preferably 80% by weight. It is more than %. If the moisture absorption rate is too low, the amount of moisture absorption tends to be insufficient.

The installation position of the humidity control sheet 8 is not particularly limited as long as it is within the internal space of the package 11, but it is preferably attached to the protection pads 7 mounted on both ends of the film roll 3. The protection pad 7 is a disk-shaped plastic sheet with a core through hole formed in the center, and is installed to prevent winding misalignment or protect the end of the film roll 3 from impact.

Additionally, it is preferable that the protective pad 7 and the humidity control sheet 8 are substantially the same size as the end surface of the roll 3.

FIG. 3 is a schematic cross-sectional view showing an enlarged portion of a package 21 according to the second embodiment of the present invention, and FIG. 4 is a perspective view showing the packaging sequence of the film roll 3 in the package 21.

In this embodiment, as shown in FIG. 4(c), the two ends of the core pipe 2 in the water vapor barrier film 4 on the axial direction side are the ends of the core pipe 2 protruding from the film roll 3. By inserting each inside from above, the water vapor barrier film 4 is wound so as to surround the end of the core pipe 2 and is fixed to the core pipe 2. Additionally, the absorbent material 6 is disposed inside the core pipe 2, and the package 21 of this embodiment is completed.

In addition, in FIG. 3, for ease of understanding, the space between the water vapor barrier film 4, the film roll 3, and the core pipe 2 is drawn with an empty space, but in reality, the water vapor barrier film 4 is connected to the film roll 3. and is wound so as to be in close contact with the core pipe (2).

An absorbent material (6) is disposed inside the core pipe (2), and moisture condensed on the inner periphery of the core pipe (2) is absorbed by the absorbent material (6), thereby forming a structure of the core pipe (2) and the water vapor barrier film (4). It is possible to suppress moisture from entering the internal space from the inside of the core pipe 2. Moreover, by folding the end of the water vapor barrier film 4 into the inside of the core pipe 2 and wrapping it so as to surround the end of the core pipe 2, there is a gap between the inner peripheral surface of the core pipe 2 and the water vapor barrier film 4. It is possible to prevent moisture from entering the internal space. With the above configuration, the humidity of the internal space where the film roll 3 is disposed can be controlled to 20 to 80%RH.

Fig. 5 is an enlarged schematic cross-sectional view showing a part of the package 101 in the second embodiment when the absorbent material 6 is not disposed. In the package 101 shown in FIG. 5, since the absorbent material 6 is not disposed, the end of the water vapor barrier film 4 may float away from the inner peripheral surface of the core pipe 2, creating a gap, and the core pipe 2 may have a gap. There is a risk of moisture entering through this gap on the inside of the.

However, in this embodiment, as shown in FIG. 3, the absorbent material 6 is disposed inside the core pipe 2 so as to be in close contact with the inner peripheral portion of the core pipe 2, so that the end portion of the water vapor barrier film 4 is It is in close contact with the inner peripheral surface of the core pipe 2, and it becomes more difficult to create a gap between the inner peripheral surface of the core pipe 2 and the water vapor barrier film 4, making it possible to more reliably prevent moisture from entering the internal space.

The absorbent material 6 used in this embodiment is preferably cylindrical or cylindrical with an outer diameter of 10 to 30 cm, and is an absorbent material ( 6) is selected. Particularly preferably, the outer diameter is 13 to 25 cm, and even more preferably, the outer diameter is 15 to 22 cm. If the outer diameter is too small, the absorption effect tends to be insufficient, and if it is too large, the weight of the package 21 tends to increase. Naturally, it is desirable that the absorbent material 6 is of such a size that it can be smoothly inserted during storage or transportation and can be smoothly removed other than during storage or transportation. The absorbent material 6 may be installed only at both ends inside the core pipe 2, or may be installed along the entire axial direction of the core pipe 2, and the number of absorbers 6 to be installed may be one or multiple. .

In the case where the absorbent material 6 is provided at both ends inside the core pipe 2, the length of the absorbent material 6 in the axial direction is the both ends of the core pipe 2 of the water vapor barrier film 4 folded into the core pipe 2. It is preferable that it is more than the length from the tip to the tip, and it is especially preferable that it exceeds this length.

The material of the absorbent material 6 is preferably made of resin from the viewpoint of strength, and the weight is preferably 20 kg or less from the viewpoint of reducing the weight of the package 21. Also, from the viewpoint of reducing the weight and not damaging the inner peripheral part of the core pipe 2, it is preferable that the sponge be in the form of a sponge with pores in the micron unit, and polyvinyl alcohol sponge or urethane sponge is particularly preferable.

Examples of sponges having pores in the micron unit include those with an apparent density of 0.01 to 0.5 g/cm3.

The humidity of the internal space of the packages 11 and 21 of the above embodiments 1 and 2 can be measured with a hygrometer by installing an opening in the water vapor barrier film 4, but in the present invention, it is possible to simply check the humidity history during transportation. From a safety standpoint, it is desirable to use an electronically recordable card type or seal type humidity indicator.

Examples of such electronically recordable card type humidity indicators include “Ondotori” manufactured by T&D Corporation, “WATCH LOGGER” manufactured by Fujita Electronics Ltd., and “Midi LOGGER” manufactured by Graphtech.

Additionally, seal-type humidity indicators include those using compounds such as cobalt bromide, which irreversibly develop color when exposed to high humidity or low humidity for a predetermined period of time. For example, a plurality of labels with a diameter of about 5 mm are lined up on the surface of the film, and these labels are 50%RH detection label, 60%RH detection label, 70%RH detection label, 80%RH detection label, and 90%RH detection label. It is a label, and the maximum achieved humidity is confirmed by the label corresponding to the achieved humidity changing color from blue to pink, changing color from white to blue, or becoming blue. Humidity indicators ranging from 5%RH on the low humidity side to 90%RH on the high humidity side are commercially available. The measurement accuracy is approximately ±5%RH.

In the present invention, the humidity indicator can be packaged together with the film roll 3, and specifically, the humidity indicator can be packaged by attaching it to the outermost layer of the film roll 3 or the inside of the water vapor barrier film 4.

Hereinafter, the polyvinyl alcohol-based film used in the present invention will be described. The polyvinyl alcohol-based film of the present invention can be obtained by forming a film by casting an aqueous solution of polyvinyl alcohol-based resin into a cast mold and continuously drying it using a metal heating roll.

As the polyvinyl alcohol-based resin, an unmodified polyvinyl alcohol-based resin is usually used, that is, a resin produced by saponifying polyvinyl acetate obtained by polymerizing vinyl acetate. If necessary, a resin obtained by saponifying a copolymer of vinyl acetate and a small amount (usually 10 mol% or less, preferably 5 mol% or less) of a component copolymerizable with vinyl acetate may be used. Components that can be copolymerized with vinyl acetate include, for example, unsaturated carboxylic acids (including, for example, salts, esters, amides, nitriles, etc.), olefins having 2 to 30 carbon atoms (for example, ethylene, propylene, n- butene, isobutene, etc.), vinyl ethers, unsaturated sulfonates, etc. Additionally, a modified polyvinyl alcohol-based resin obtained by chemically modifying the hydroxyl group after saponification can also be used.

Additionally, as the polyvinyl alcohol-based resin, a polyvinyl alcohol-based resin having a 1,2-diol structure in the side chain can also be used. Such a polyvinyl alcohol-based resin having a 1,2-diol structure in the side chain is, for example, (i) saponifying a copolymer of vinyl acetate and 3,4-diacetoxy-1-butene, (ii) ) Method of saponifying and decarboxylating a copolymer of vinyl acetate and vinylethylene carbonate; (iii) Saponifying and decarboxylating a copolymer of vinyl acetate and 2,2-dialkyl-4-vinyl-1,3-dioxolone It can be obtained by deoxidation, (iv) saponification of a copolymer of vinyl acetate and glycerin monoallyl ether, etc.

The weight average molecular weight of the polyvinyl alcohol-based resin is preferably 100,000 to 300,000, particularly preferably 110,000 to 280,000, and even more preferably 120,000 to 260,000.

If this weight average molecular weight is too small, it tends to be difficult to obtain sufficient optical performance when producing an optical film from polyvinyl alcohol-based resin, and if it is too large, it is difficult to obtain sufficient optical performance when stretching a polyvinyl alcohol-based film to form a polarizing film. Stretching becomes difficult, which tends to make industrial production difficult.

In addition, the weight average molecular weight of the polyvinyl alcohol-based resin is the weight average molecular weight measured by the GPC-MALS method.

The average degree of saponification of the polyvinyl alcohol-based resin used in the present invention is preferably 98 mol% or more, particularly preferably 99 mol% or more, more preferably 99.5 mol% or more, and particularly preferably 99.8 mol% or more. . If this average degree of saponification is too small, sufficient optical performance tends not to be obtained when forming a polarizing film from a polyvinyl alcohol-based film.

Here, the average degree of saponification in the present invention is measured according to JIS K 6726.

As the polyvinyl alcohol-based resin used in the present invention, two or more types of different types, such as modified species, modified amount, weight average molecular weight, and average degree of saponification, may be used in combination.

An aqueous polyvinyl alcohol-based resin solution is prepared using such a polyvinyl alcohol-based resin. It is preferable to wash the polyvinyl alcohol-based resin with water and dehydrate it using a centrifuge or the like to obtain a polyvinyl alcohol-based resin wet cake with a water content of 50% by weight or less. If the water content of such a wet cake is too large, it tends to be difficult to adjust it to the desired aqueous solution concentration.

Such a polyvinyl alcohol-based resin wet cake is dissolved in warm water or hot water to prepare an aqueous polyvinyl alcohol-based resin solution.

The method for preparing the polyvinyl alcohol-based resin aqueous solution is not particularly limited. For example, it can be prepared using a heated multi-screw extruder, or the polyvinyl alcohol described above can be placed in a dissolution can equipped with a stirring blade for generating an upward and downward circulation flow. An alcohol-based resin wet cake can be added and dissolved by blowing steam into the can to prepare an aqueous solution of desired concentration.

In addition to polyvinyl alcohol-based resin, the polyvinyl alcohol-based resin aqueous solution contains commonly used plasticizers such as glycerin, diglycerin, triglycerin, ethylene glycol, triethylene glycol, polyethylene glycol, and trimethyolpropane, and nonionic and anionic plasticizers. It is preferable from the viewpoint of film forming properties of the polyvinyl alcohol-based film to contain at least one type of surfactant selected from the group consisting of a cationic surfactant and a cationic surfactant.

The resin concentration of the polyvinyl alcohol-based resin aqueous solution thus obtained is preferably 15 to 60% by weight, particularly preferably 17 to 55% by weight, and even more preferably 20 to 50% by weight.

If the resin concentration of such an aqueous solution is too low, the drying load increases and production capacity tends to decrease, and if it is too high, the viscosity tends to become too high, making uniform dissolution difficult.

The polyvinyl alcohol-based film of the present invention is prepared by using the above-mentioned polyvinyl alcohol-based resin to prepare a polyvinyl alcohol-based resin aqueous solution, discharging and casting this aqueous solution into a casting mold, and forming a film by the casting method. , it can be manufactured continuously by drying, for example, by the following processes (A) to (D).

(A) Process of forming a film by casting method

(B) Process of heating and drying the formed film

(C) Process of obtaining a film roll by slitting the dried film and then winding it into a roll.

(D) A process of packaging a film roll with a vapor barrier film (repackaging film if necessary) to form a packaging body.

Here, examples of the cast type include cast drums (drum-type rolls) and endless belts, but cast drums are preferable from the viewpoints of widening, lengthening, and excellent film thickness uniformity. Hereinafter, the case of a cast drum will be described.

Hereinafter, the above steps (A) to (D) will be explained in order.

[Process (A)]

In step (A), first, the polyvinyl alcohol-based resin aqueous solution is usually subjected to a defoaming treatment. Examples of the defoaming method include static defoaming and defoaming using a multi-screw extruder with a vent. As a multi-screw extruder with a vent, a twin-screw extruder with a vent is usually used.

After the degassing treatment, a certain amount of the polyvinyl alcohol-based resin aqueous solution is introduced into a T-shaped slit die and cast into a cast mold to form a film.

The temperature of the polyvinyl alcohol-based resin aqueous solution at the outlet of the T-shaped slit die is preferably 80 to 100°C, and particularly preferably 85 to 98°C.

If the temperature of such aqueous polyvinyl alcohol resin solution is too low, it tends to flow poorly, and if it is too high, it tends to foam.

The viscosity of such aqueous polyvinyl alcohol-based resin solution is preferably 50 to 200 Pa·s at the time of discharge, and particularly preferably 70 to 150 Pa·s.

If the viscosity of such an aqueous solution is too low, it tends to flow poorly, and if it is too high, casting tends to be difficult.

The discharge speed of the polyvinyl alcohol-based resin aqueous solution discharged from the T-type slit die to the cast drum is preferably 0.1 to 5 m/min, particularly preferably 0.2 to 4 m/min, and even more preferably 0.3 to 3 m/min. If this discharge speed is too low, productivity tends to decrease, and if it is too high, casting tends to become difficult.

The diameter of such a cast drum is preferably 2 to 5 m, particularly preferably 2.4 to 4.5 m, and even more preferably 2.8 to 4 m. If this diameter is too small, the drying length is insufficient and the transport speed of the film formed on the drum tends to be low, and if it is too large, transportability tends to be reduced.

The width of such a cast drum is preferably 4 m or more, particularly preferably 4.5 m or more, more preferably 5 m or more, and particularly preferably 5 to 7 m. If the width of the cast drum is too small, productivity tends to decrease.

The rotation speed of such a cast drum is preferably 3 to 50 m/min, particularly preferably 4 to 40 m/min, and even more preferably 5 to 35 m/min.

The surface temperature of such a cast drum is preferably 40 to 99°C, and particularly preferably 60 to 95°C.

If this surface temperature is too low, it tends to dry poorly, and if it is too high, it tends to foam.

[Process (B)]

Next, the above step (B) is explained.

Process (B) is a process of heating and drying the formed polyvinyl alcohol-based film.

Drying of the film formed with a cast drum is carried out by alternately contacting the front and back surfaces of the film with a plurality of metal heating rolls. The surface temperature of the metal heating roll is usually 40 to 150°C, preferably 50 to 140°C. If this surface temperature is too low, it tends to dry poorly, and if it is too high, it tends to dry too much, causing appearance defects such as waves. In addition, the metal heating roll is, for example, a roll with a diameter of 0.2 to 2 m whose surface is hard chrome plated or mirror-finished, and drying can be carried out using usually 2 to 30 rolls, preferably 10 to 25 rolls. there is.

In the present invention, it is preferable to heat-treat the film after drying with a metal heating roll. The heat treatment temperature is preferably 60 to 150°C, and particularly preferably 70 to 140°C. If the heat treatment temperature is too low, the water resistance of the polyvinyl alcohol-based film tends to be insufficient or it tends to cause phase difference, and if it is too high, the stretchability during production of the polarizing film tends to decrease. Such heat treatment methods include, for example, a method using a floating dryer, a method of once cooling to room temperature after drying, and then contacting a high-temperature metal heating roll again, or irradiating near-infrared rays to both sides of the film using an infrared lamp. How to do it, etc.

In addition, the above described a method of preparing a polyvinyl alcohol-based resin aqueous solution, casting this aqueous solution into a cast mold, forming a film by the casting method, and drying to produce a polyvinyl alcohol-based film, but the polyvinyl alcohol-based resin solution It is also possible to produce a polyvinyl alcohol-based film by casting it on a resin film or a metal belt, forming it into a film, and drying it.

[Process (C)]

Drying is performed in step (B), and the film to which heat treatment has been applied as necessary goes through step (C) to become a product (polyvinyl alcohol-based film of the present invention).

In step (C), the dried film is cut with slits at both ends and wound on a core pipe (hereinafter referred to as a roll) whose axial length is longer than the film width, and the strip-shaped polyvinyl alcohol-based film is wound into a roll. It is a process that is taken.

By the above-described method, a film roll in which a polyvinyl alcohol-based film is wound around the roll is produced.

The length of the polyvinyl alcohol-based film is preferably 4 km or more from the viewpoint of increasing the area, particularly preferably 4.5 km or more from the viewpoint of further increasing the area, and more preferably 5 to 50 km from the viewpoint of transport weight.

Moreover, the thickness of the polyvinyl alcohol-based film of the present invention is preferably 60 μm or less from the viewpoint of thinning the polarizing film, particularly preferably 50 μm or less from the viewpoint of further thinning, and even more preferably from the viewpoint of fracture avoidance. It is 5 to 40㎛.

Such a polyvinyl alcohol-based film is very suitably used as an optical polyvinyl alcohol-based film, and is also particularly preferably used as a disk for a polarizing film.

〔Process (D)〕

The obtained film roll becomes a package through the above step (D).

As described above, step (D) is a step of packaging the film roll with a water vapor barrier film and, if necessary, packaging it again with a packaging film to form a package. After storage, the obtained package is transported toward the shipping location and is used, for example, to manufacture a polarizing film.

[Storage and/or transportation]

The package consisting of film rolls is supported in a so-called floating state for storage or transportation without contacting the floor by installing brackets (support plates) on the protrusions at both ends of the core pipe or placing the protrusions at both ends on a stand. When the width of the film is relatively small, a bracket is usually used, and when the width of the film is relatively large, a stand is usually used.

In the case of wide film rolls, a stand is usually used. The stand is made up of a pair of supports on both sides connected by a connecting plate. The support straddles the frame portion horizontally between supports at both ends of the base, and the protrusion of the core pipe is placed on the frame portion of the support.

When storing and/or transporting packaged film rolls, it is desirable to avoid extreme high or low temperature, low humidity, or high humidity conditions, and specifically, the temperature is 10 to 30°C and humidity is 40 to 75%RH.

However, the main feature of the package of the present invention is that there is no concern about winding misalignment of the film roll even when exposed for a long time in a harsh atmosphere that deviates from such conditions, and a remarkable effect is exhibited.

Hereinafter, a method for manufacturing a polarizing film that can be obtained using the polyvinyl alcohol-based film of the present invention will be described.

The polarizing film of the present invention is manufactured by unwinding the polyvinyl alcohol-based film from a roll, transferring it in the horizontal direction, and going through processes such as swelling, dyeing, boric acid crosslinking, stretching, washing, and drying.

The swelling process is performed before the dyeing process. In addition to being able to clean dirt on the surface of the polyvinyl alcohol-based film through the swelling process, swelling the polyvinyl alcohol-based film also has the effect of preventing staining, etc. Water is usually used as a treatment liquid in the swelling process. If the main component of the treatment liquid is water, it may contain small amounts of additives such as iodinated compounds, surfactants, and alcohol. The temperature of the swelling bath is usually about 10 to 45°C, and the immersion time in the swelling bath is usually about 0.1 to 10 minutes.

The dyeing process is carried out by contacting the film with a liquid containing iodine or a dichroic dye. Usually, an aqueous solution of iodine-potassium iodide is used, and the appropriate concentration of iodine is 0.1 to 2 g/L and the concentration of potassium iodide is 1 to 100 g/L. The practical dyeing time is about 30 to 500 seconds. The temperature of the treatment bath is preferably 5 to 50°C. The aqueous solution may contain a small amount of an organic solvent compatible with water in addition to the water solvent.

The boric acid crosslinking process is carried out using boron compounds such as boric acid or borax. The boron compound is used in the form of an aqueous solution or a water-organic solvent mixture at a concentration of about 10 to 100 g/L, and it is preferable to coexist potassium iodide in the solution from the viewpoint of stabilizing polarization performance. The temperature during treatment is preferably about 30 to 70°C, and the treatment time is preferably about 0.1 to 20 minutes, and stretching can also be performed during treatment if necessary.

The stretching process is performed 3 to 10 times, preferably 3.5 to 6 times, in the uniaxial direction. At this time, a slight stretching (stretching to the extent of preventing shrinkage in the width direction or more) may be performed in a direction perpendicular to the stretching direction. The temperature during stretching is preferably 30 to 170°C. Additionally, the stretching ratio may be ultimately set within the above range, and the stretching operation can be performed not only in the first stage but also in any range of stages in the manufacturing process.

The cleaning process is performed, for example, by immersing the polyvinyl alcohol-based film in water or an aqueous iodide solution such as potassium iodide, and this process can remove precipitates that occur on the surface of the film. When using an aqueous potassium iodide solution, the potassium iodide concentration is preferably about 1 to 80 g/L. The temperature during washing treatment is usually 5 to 50°C, preferably 10 to 45°C. The processing time is usually 1 to 300 seconds, preferably 10 to 240 seconds. Additionally, washing with water and washing with an aqueous potassium iodide solution may be performed in appropriate combination.

The drying process may be performed in the air at 40 to 80°C for 1 to 10 minutes.

Moreover, the polarization degree of the polarizing film is preferably 99.8% or more, particularly preferably 99.9% or more. If the degree of polarization is too low, there is a tendency that contrast in the liquid crystal display cannot be secured.

In addition, the degree of polarization is generally determined by the light transmittance (H ₁₁ ) measured for the wavelength λ in a state in which two polarizing films are overlapped so that their orientation directions are in the same direction, and the direction in which the orientation directions of the two polarizing films are orthogonal to each other. It is calculated according to the following formula from the light transmittance (H ₁ ) measured for the wavelength λ in a state of overlapping as much as possible.

[(H ₁₁ -H ₁ )/(H ₁₁ +H ₁ )] ^{1 /2}

Furthermore, the single transmittance of the polarizing film of the present invention is preferably 42% or more, particularly preferably 43% or more.

If this single transmittance is too low, there is a tendency that high brightness of the liquid crystal display cannot be achieved.

The single transmittance is a value obtained by measuring the light transmittance of the polarizing film alone using a spectrophotometer.

The polarizing film obtained in this way becomes a polarizing plate by attaching an optically isotropic resin film as a protective film to one or both sides of the polarizing film using an adhesive. As a protective film, for example, cellulose triacetate, cellulose diacetate, polycarbonate, polymethyl methacrylate, cycloolefin polymer, cycloolefin copolymer, polystyrene, polyether sulfone, polyarylene ester, poly-4-methyl. Films or sheets of pentene, polyphenylene oxide, etc. can be mentioned.

Bonding is performed by a known method; for example, a liquid adhesive composition is uniformly applied to a polarizing film, a protective film, or both, then the two are bonded together and pressed, and then heated or irradiated with active energy rays. It is carried out by doing.

In addition, for the purpose of thinning the polarizing film, instead of the protective film, a curable resin such as urethane resin, acrylic resin, or urea resin can be applied to one or both sides and cured to form a polarizing plate.

The polarizing film obtained by the present invention has no defects and is excellent in in-plane uniformity of polarization performance, and is used in liquid crystals of portable information terminals, PCs, televisions, projectors, signage, electronic desk calculators, electronic watches, word processors, automobiles and machinery instruments, etc. It is preferably used in display devices, sunglasses, anti-glare glasses, three-dimensional glasses, wearable displays, anti-reflection layers for display elements (CRT, LCD, organic EL, electronic paper, etc.), optical communication devices, medical devices, building materials, toys, etc.

(Example)

Hereinafter, the present invention will be described in detail by way of examples, but the present invention is not limited to the following examples as long as it does not exceed the gist of the present invention.

＜Measurement conditions＞

(1) Optical staining of polyvinyl alcohol-based film

Cut a test piece of polyvinyl alcohol-based film measuring 30 cm in length Optical stains were observed in transmission mode using a light box at 14,000 lx and evaluated based on the following criteria.

○···Lightness and darkness cannot be seen within the surface.

×···The joke can be seen on the front page.

(2) Polarization degree of polarizing film (%), single transmittance (%)

Centering on the longitudinal center of the obtained polarizing film, a total of 9 test pieces were cut at 3 points in the longitudinal direction and 3 points each in the width direction of 4 cm in length ) was used to measure the polarization degree and single transmittance, and each average value was taken as the polarization degree and single transmittance of the polarizing film.

(3) Stains on the polarizing film

From the obtained polarizing film, a test piece with a length of 30 cm The stains were observed in transmission mode using an in-light box and evaluated according to the following criteria.

○ ···No stains

△···Slight stains

×···Stained

<Example 1>

(Manufacture of film rolls)

Add 1,000 kg of polyvinyl alcohol-based resin with a weight average molecular weight of 142,000 and a degree of saponification of 99.8 mol%, 2,500 kg of water, and 100 kg of glycerin as a plasticizer, raise the temperature to 140°C while stirring, and adjust the concentration to 25% by weight of the resin to make it uniform. A well-dissolved aqueous solution of polyvinyl alcohol-based resin was obtained.

Next, the polyvinyl alcohol-based resin aqueous solution was supplied to a twin-screw extruder and degassed, the temperature of the aqueous solution was set to 95°C, and the film was formed by discharging and casting from the T-slit die discharge port onto a cast drum with a surface temperature of 90°C.

Next, the obtained film was dried with a plurality of metal heating rolls, heat treated using a floating dryer, and cut into slits 4 m wide. Finally, by winding and unwinding an aluminum core pipe with an outer diameter of 17 cm, an inner diameter of 16 cm, and a length of 4.4 m, a strip-shaped polyvinyl alcohol-based film (width 4 m, length 5 km, thickness 40 ㎛) with a water content of 4% by weight is wrapped around the core pipe. A coiled film roll was obtained. A test piece of the polyvinyl alcohol-based film was cut from the tip of the obtained film roll, and optical staining was observed. The results are as shown in Table 1.

(Manufacture of packaging)

First, two sheets of disk-shaped polystyrene foam (diameter of through hole 18 cm) with a diameter of 60 cm and a thickness of 4 mm were prepared as a protection pad, and on the contact surface with the end of the film roll of the protection pad, a “Bel” manufactured by Teijin Corporation was placed as a humidity control sheet. After attaching “Sunny F” (diameter 60 cm, thickness 0.8 mm, through hole diameter 18 cm), the protective pad was passed through the core pipe and attached to both ends of the film roll. The moisture absorption rate of the moisture control sheet at 30°C and 90%RH is 100% by weight. Next, a laminated film of aluminum-deposited polyester film (polyethylene terephthalate film with 50 nm of aluminum deposited on it, 12㎛ thick) and polyethylene film (25㎛ thick) was prepared as a water vapor barrier film, and humidity was applied to the polyethylene side, which is the inner surface of the package. An indicator (manufactured by Fujita Electronics Seisakusho, “WATCHLOGGERKT-275”) was attached.

Finally, in an environment of 23°C and 50%RH, the vapor barrier film was double wound around the obtained film roll, and the excess portion on the axial direction side of the core pipe was wrapped around the core pipe with tape to seal the film roll, thereby obtaining a package. .

(keep)

The protrusion from the film roll of the core pipe is placed on a stand, and the obtained package is suspended in the air without being grounded, and stored at 60°C and 90%RH for 10 days, then at 10°C and 10%RH for 10 days, and then at 25°C. , stored at 50%RH for 10 days. The package after storage was defrosted and the humidity history of the internal space of the package was checked using a humidity indicator. The minimum humidity was 40%RH and the maximum humidity was 60%RH. No winding misalignment occurred in the film roll after storage. Additionally, when the film was rolled 20 m from the film roll and the deformation and optical staining of the film were observed, no differences compared to before storage could be confirmed.

(Manufacture of polarizing film)

A test piece of polyvinyl alcohol-based film with a width (TD direction) of 30 cm did. Next, it was immersed in an aqueous solution of 0.5 g/L of iodine and 30 g/L of potassium iodide at 28°C, stretched 1.6 times while dyed, and then continuously immersed in an aqueous solution of 40 g/L of boric acid and 30 g/L of potassium iodide (55°C). It was immersed, uniaxially stretched 2.1 times, and treated with boric acid. Afterwards, it was washed with an aqueous potassium iodide solution and dried to obtain a polarizing film with a total stretching ratio of 5.8 times. The polarization characteristics of the obtained polarizing film are shown in Table 2.

<Example 2>

The packaging was manufactured and stored in the same manner as in Example 1, except that a moisture-absorbing film laminated layer (NS-APP, manufactured by Nisshin Seal Industry Co., Ltd.) was used as a vapor barrier film and a humidity control sheet was not used. , the production of a polarizing film was carried out. The results are shown in Tables 1 and 2.

<Example 3>

As a vapor barrier film, prepare a laminated film of aluminum-deposited polyester film (polyethylene terephthalate film with 50 nm of aluminum deposited, 12㎛ thick) and polyethylene film (25㎛ thick), and place a humidity indicator on the polyethylene side, which becomes the inner surface of the package. (manufactured by Fujita Electronics Seisakusho, “WATCHLOGGERKT-275”) was attached. Next, in an environment of 23°C and 50%RH, the water vapor barrier film was double wound around the film roll of Example 1 with the polyethylene film on the inside. The axial end of the core pipe in the water vapor barrier film is fixed to the outer periphery of the end of the core pipe protrusion (0.2 m on both ends) using a rubber band, and the excess portion of the water vapor barrier film is placed inside the core pipe to cover the ends of the core pipe. folded into Additionally, the length of the water vapor barrier film portion folded from one end of the core pipe is 0.4 m.

Finally, two cylindrical polyvinyl alcohol sponges (PVA sponges manufactured by Aion) with an outer diameter of 16 cm, an inner diameter of 10 cm, and a length of 0.5 m as absorbents are inserted into the inner pipes from both ends of the core pipe, so that the cross section of the absorbent material matches the end of the core pipe. got a sieve The weight of one such absorbent material is 1.4 kg.

Using the obtained package, storage and production of a polarizing film were carried out in the same manner as in Example 1. The results are shown in Tables 1 and 2.

<Example 4>

Production and storage of the package, and production of the polarizing film were carried out in the same manner as in Example 3, except that a cylindrical urethane sponge (polyurethane sponge manufactured by Aion Corporation) with an outer diameter of 16 cm, an inner diameter of 10 cm, and a length of 0.5 m was used as the absorbent material. . The weight of one such absorbent material is 1.3 kg. The results are shown in Tables 1 and 2.

<Comparative Example 1>

The packaging was manufactured and stored, and the polarizing film was manufactured in the same manner as in Example 3, except that no absorbent material was used. The results are shown in Tables 1 and 2.

From the results of Examples 1 to 4, the polyvinyl alcohol-based film stored in the package of the present invention is not deformed during storage because the humidity of the internal space where the film roll is placed is controlled to 20 to 80% RH during storage. It can be seen that stains are unlikely to occur, and optical stains remain small even after storage, unchanged from the initial stage. In addition, since the polarizing film produced from the package of the present invention is suppressed from deformation of the polyvinyl alcohol-based film used for production and deterioration of optical performance, the degree of polarization and single transmittance are high, and color unevenness is unlikely to occur.

The polarizing film manufactured from the package of the present invention has excellent polarization performance and can be used in portable information terminals, PCs, televisions, projectors, signage, electronic desk calculators, electronic watches, word processors, electronic papers, game machines, videos, cameras, photo albums, and thermometers. , liquid crystal displays for audio, automotive and machinery instruments, sunglasses, anti-glare glasses, 3D glasses, wearable displays, anti-reflection layers for display elements (CRT, LCD, organic EL, electronic paper, etc.), optical communication devices, medical devices, and architecture. It is preferably used in materials, toys, etc.

11, 21: packaging body, 2: core pipe,
3: Film roll, 4: Water vapor barrier film,
5: Adhesive tape, 6: Absorbent material,
7: Protection pad, 8: Humidity control sheet

Claims (12)

A package consisting of a film roll wrapped with a strip-shaped polyvinyl alcohol-based film wrapped around a core pipe and wrapped with a vapor barrier film,
The thickness of the polyvinyl alcohol-based film is 5 to 40 μm,
Protective pads with humidity control sheets attached to the contact surface with the film roll are mounted on both ends of the film roll,
The vapor barrier film is wound and fixed to the outer periphery of the core pipe so as to be in close contact with the film roll and the core pipe,
A package characterized in that the humidity of the interior space of the package is controlled to 20 to 80%RH. delete In claim 1,
A package characterized in that the humidity control sheet is a non-woven fabric with a thickness of 0.1 to 2 mm. In claim 1,
A package wherein the humidity control sheet has a moisture absorption rate of 50% by weight or more at 30°C and 90%RH. In claim 1,
The axial length of the core pipe is longer than the width of the polyvinyl alcohol-based film, and the end of the core pipe in the water vapor barrier film on the axial direction side is folded into the interior of the core pipe protruding from the film roll, thereby forming the core pipe. It is wound to cover the end,
In addition, the package is characterized in that a sponge-shaped absorbent material having micron-scale pores is disposed inside the core pipe. The method of any one of claims 1 and 3-5,
The package is characterized in that a humidity indicator is packaged together with the film roll. The method of any one of claims 1 and 3-5,
A packaging material characterized in that the polyvinyl alcohol-based film has a width of 4 m or more and a length of 4 km or more. delete The method of any one of claims 1 and 3-5,
A package characterized in that the polyvinyl alcohol-based film is a polyvinyl alcohol-based film for a polarizing film. A method for storing or transporting a polyvinyl alcohol-based film, comprising storing and/or transporting the polyvinyl alcohol-based film using the package according to any one of claims 1 and 3-5. A polyvinyl alcohol-based film characterized in that it is stored and/or transported using the package according to any one of claims 1 and 3-5. A polarizing film manufactured using the polyvinyl alcohol-based film according to claim 11.

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