JP3826991B2 - Storage or transportation method of polyvinyl alcohol polymer film for polarizing film - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for storing or transporting a polyvinyl alcohol polymer film for a polarizing film that can be stably stretched and is useful as a raw material for producing a wide polarizing film.
[0002]
[Prior art]
A polarizing plate having a light transmission and shielding function is a basic component of a liquid crystal display (LCD) together with a liquid crystal having a light switching function. This LCD can be applied to small devices such as calculators and wristwatches in the early days of development, and in recent years, laptop computers, word processors, liquid crystal color projectors, in-vehicle navigation systems, liquid crystal televisions, personal phones, and indoor and outdoor measuring devices. As the liquid crystal display screen becomes larger, a wider polarizing plate than the conventional product is required.
[0003]
The polarizing plate is generally dyed by uniaxially stretching a polyvinyl alcohol polymer film (hereinafter, the polyvinyl alcohol polymer may be abbreviated as “PVA” and the polyvinyl alcohol polymer film as “PVA film”). After the dyeing, the film was uniaxially stretched, and then fixed with a boron compound (the dyeing and fixing processes may be performed simultaneously), the cellulose triacetate (TAC) film, and the acetic acid / cellulose butyrate (CAB) film. It is the structure which bonded protective films, such as.
[0004]
The uniaxial stretching of the PVA film often employs free-width uniaxial stretching from the viewpoint of improving the polarization performance. However, free-width uniaxial stretching tends to cause shrinkage in the width direction called neck-in along with stretching, and in that case, the width of the obtained polarizing film becomes narrow, which has been a major obstacle to enlargement of the liquid crystal display screen. .
[0005]
In addition, since the polarizing film is collected with the direction of approximately 45 ° from the stretching direction as the long or short side of the liquid crystal display screen, it is necessary to secure a wide polarizing film as the liquid crystal display screen becomes larger. It has become a very important item for improving the yield. In order to obtain such a wide polarizing film, a wide PVA film is required.
[0006]
[Problems to be solved by the invention]
However, due to the widening of the PVA film, the weight of the film roll around which the PVA film is wound increases, so that the handling difficulty increases. Therefore, both ends of the film roll are damaged during storage or transportation of the film roll. By sticking, there was a problem that the PVA film was cut during stretching, or the film roll was bent during long-term storage, and wrinkles were generated in the PVA film.
[0007]
An object of the present invention is to provide a method for storing or transporting a PVA film for a polarizing film that can be stably stretched and is useful as a raw material for producing a wide polarizing film.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the method for storing or transporting a PVA film for polarizing film according to the present invention is made of metal or plastic, or plastic coated metal or metal-coated plastic, and has an outer diameter of 10 cm or more. A film is formed by winding a polyvinyl alcohol polymer film having a film thickness of 40 μm to 100 μm, a film width of 2 m or more, and a film length of 1300 m or more around a cylindrical core having a length of 2 m or more and 2 cm to 30 cm longer than the film width. The film roll is doubled with a packaging film having a moisture permeability of 10 g / m ² / day or less, with both end faces of the core projecting from both end faces of the film roll within the core length range. Wrapped in a roll for storage or transportation.
[0009]
According to the present invention, it is possible to prevent the occurrence of scratches on the end face of the film roll during storage or transportation of the film roll, and the occurrence of wrinkles of the PVA film due to the bending of the core. Therefore, stable stretching is possible and a wide polarizing film is obtained. It is done.
Here, the outer diameter of the core means the diameter of the outer circumference circle when the core is cylindrical, and the diameter of the circumscribed circle when the core is a rectangular tube shape.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
PVA which comprises the PVA film used by this invention is manufactured by saponifying the polyvinyl ester obtained by superposing | polymerizing vinyl ester, for example. In addition, the PVA is grafted with an unsaturated carboxylic acid or a derivative thereof, an unsaturated sulfonic acid or a derivative thereof, an α-olefin having 2 to 30 carbon atoms or the like at a ratio of less than 15 mol%, or a vinyl ester and an unsaturated ester. Modified PVA produced by saponifying a modified polyvinyl ester obtained by copolymerizing saturated carboxylic acid or a derivative thereof, unsaturated sulfonic acid or a derivative thereof, an α-olefin having 2 to 30 carbon atoms or the like at a ratio of less than 15 mol%, Examples thereof include so-called polyvinyl acetal resins obtained by crosslinking a part of hydroxyl groups of unmodified or modified PVA with aldehydes such as formalin, butyraldehyde, and benzaldehyde.
[0011]
Examples of the vinyl ester include vinyl acetate, vinyl formate, vinyl propionate, vinyl butyrate, vinyl pivalate, vinyl versatate, vinyl laurate, vinyl stearate, vinyl benzoate and the like.
[0012]
On the other hand, the comonomer used in the modified PVA is copolymerized mainly for the purpose of modifying the PVA, and is used within a range not impairing the gist of the present invention. Examples of such comonomers include olefins such as ethylene, propylene, 1-butene, and isobutene; acrylic acid and salts thereof; methyl acrylate, ethyl acrylate, n-propyl acrylate, i-propyl acrylate, and n-acrylate. -Acrylic esters such as butyl, i-butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, octadecyl acrylate; methacrylic acid and salts thereof; methyl methacrylate, ethyl methacrylate Methacrylic acid such as n-propyl methacrylate, i-propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, dodecyl methacrylate, octadecyl methacrylate ester Acrylamides such as acrylamide, N-methyl acrylamide, N-ethyl acrylamide, N, N-dimethyl acrylamide, diacetone acrylamide, acrylamide propane sulfonic acid and salts thereof, acrylamide propyl dimethylamine and salts thereof, N-methylol acrylamide and derivatives thereof; Derivatives; Methacrylamide derivatives such as methacrylamide, N-methyl methacrylamide, N-ethyl methacrylamide, methacrylamide propane sulfonic acid and salts thereof, methacrylamide propyl dimethylamine and salts thereof, N-methylol methacrylamide and derivatives thereof; N -N-vinylamides such as vinylformamide, N-vinylacetamide, N-vinylpyrrolidone; methyl vinyl ether, Vinyl ethers such as ruvinyl ether, n-propyl vinyl ether, i-propyl vinyl ether, n-butyl vinyl ether, i-butyl vinyl ether, t-butyl vinyl ether, dodecyl vinyl ether, stearyl vinyl ether; nitriles such as acrylonitrile and methacrylonitrile; vinyl chloride , Vinyl halides such as vinylidene chloride, vinyl fluoride and vinylidene fluoride; allyl compounds such as allyl acetate and allyl chloride; maleic acid and salts thereof or esters thereof; itaconic acid and salts thereof or esters thereof; vinyltrimethoxysilane And vinyl silyl compounds such as isopropenyl acetate. Of these, α-olefins are preferable, and ethylene is particularly preferable.
[0013]
The modified amount of the modified PVA is preferably less than 15 mol%.
[0014]
The saponification degree of PVA is preferably 95 mol% or more, more preferably 98 mol% or more, further preferably 99 mol% or more, and most preferably 99.5 mol% or more from the viewpoint of polarization performance and durability.
[0015]
The saponification degree indicates the ratio of units that are actually saponified to vinyl alcohol units among units that can be converted to vinyl alcohol units by saponification. The saponification degree of PVA was measured by the method described in JIS.
[0016]
The polymerization degree of PVA is preferably 500 or more, more preferably 1500 or more, and most preferably 2500 or more from the viewpoint of polarization performance and durability. The upper limit of the degree of PVA polymerization is preferably 8000 or less, and more preferably 6000 or less.
[0017]
The degree of polymerization of PVA is measured according to JIS K 6726. That is, it is calculated | required from the intrinsic viscosity measured in 30 degreeC water after re-saponifying and refine | purifying PVA.
[0018]
As a method for producing the PVA film, for example, using a PVA solution in which PVA is dissolved in a solvent, a casting film forming method, a wet film forming method (discharging into a poor solvent), a dry and wet film forming method, Gel film forming method (a method of obtaining a PVA film by extracting and removing a solvent after cooling and gelling a PVA aqueous solution once), a method based on a combination thereof, and a hydrous PVA (which may contain an organic solvent, etc.) A melt extrusion film forming method performed by melting can be employed. Among these, the casting film forming method and the melt extrusion film forming method are preferable because a highly transparent PVA film can be obtained.
[0019]
Examples of the solvent for dissolving PVA used in producing the PVA film include dimethyl sulfoxide, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, ethylene glycol, glycerin, propylene glycol, diethylene glycol, triethylene glycol, and tetraethylene. Glycol, trimethylolpropane, ethylenediamine, diethylenetriamine, glycerin, water and the like can be mentioned, and one or more of these can be used. Among these, dimethyl sulfoxide, water, or a mixed solvent of glycerin and water is preferably used.
[0020]
The PVA concentration of the PVA solution or water-containing PVA used in producing the PVA film is preferably 10 to 70% by weight, more preferably 10 to 60% by weight, and further preferably 13 to 55% by weight. Yes, 15 to 50% by weight is most preferred. The PVA solution or the hydrous PVA may contain a plasticizer, a surfactant, a dichroic dye, or the like as necessary.
[0021]
When producing a PVA film, it is preferable to add a polyhydric alcohol as a plasticizer. Examples of the polyhydric alcohol include ethylene glycol, glycerin, propylene glycol, diethylene glycol, diglycerin, triethylene glycol, tetraethylene glycol, trimethylolpropane, etc., and one or more of these are used. can do. Among these, diglycerin, ethylene glycol, and glycerin are preferably used because of the effect of improving stretchability.
[0022]
The addition amount of the polyhydric alcohol is preferably 1 to 30 parts by weight, more preferably 3 to 25 parts by weight, and most preferably 5 to 20 parts by weight with respect to 100 parts by weight of PVA. If the amount is less than 1 part by weight, the dyeability and stretchability may be lowered. If the amount is more than 30 parts by weight, the PVA film may be too soft and the handleability may be lowered.
[0023]
When producing a PVA film, it is preferable to add a surfactant. The type of the surfactant is not particularly limited, but an anionic or nonionic surfactant is preferable. As the anionic surfactant, for example, a carboxylic acid type such as potassium laurate, a sulfate type such as octyl sulfate, and a sulfonic acid type anionic surfactant such as dodecylbenzenesulfonate are suitable. Nonionic surfactants include, for example, alkyl ether types such as polyoxyethylene oleyl ether, alkylphenyl ether types such as polyoxyethylene octylphenyl ether, alkyl ester types such as polyoxyethylene laurate, and polyoxyethylene laurylamino. Alkylamine type such as ether, alkylamide type such as polyoxyethylene lauric acid amide, polypropylene glycol ether type such as polyoxyethylene polyoxypropylene ether, alkanolamide type such as oleic acid diethanolamide, polyoxyalkylene allyl phenyl ether, etc. Nonionic surfactants such as allyl phenyl ether type are preferred. These surfactants can be used alone or in combination of two or more.
[0024]
The addition amount of the surfactant is preferably 0.01 to 1 part by weight, more preferably 0.02 to 0.5 part by weight, and most preferably 0.05 to 0.3 part by weight with respect to 100 parts by weight of PVA. . If the amount is less than 0.01 part by weight, the effect of improving stretchability and dyeing property is hardly exhibited, and if the amount is more than 1 part by weight, it may elute on the surface of the PVA film and cause blocking, and the handleability may be reduced. .
[0025]
In the present invention, when the PVA film is formed, it is preferably dried with two or more multistage rolls. When dried with only a single roll or metal belt, curling in water becomes intense and it is difficult to perform uniform stretching.
[0026]
As each drying surface of the multi-stage roll of two or more stages, one heated by steam, a heating medium, hot water, an electric heater or the like can be used. In addition, means such as blowing warm air or cold air on the PVA film or sucking air or steam around the PVA film may be used as an auxiliary. Furthermore, in the case of the third and subsequent drying, not only roll drying but also a floating dryer such as a tenter method or a free method can be used.
[0027]
In the present invention, the PVA film has a film width of 2 m or more, preferably 2.3 m or more, more preferably 2.6 m or more, further preferably 3 m or more, and most preferably 3.3 m or more. When the film width is narrower than 2 m, the influence of neck-in extends to the vicinity of the central portion of the PVA film, and a wide polarizing film with good polarization performance cannot be obtained. Moreover, when the film width of a PVA film exceeds 6 m, since it may be difficult to stretch uniformly by uniaxial stretching, the film width is preferably 6 m or less, and more preferably 5 m or less.
[0028]
The thickness of the PVA film is 40 to 100 μm, preferably 45 to 90 μm, and more preferably 50 to 80 μm. If the thickness of the PVA film is less than 40 μm, the draw ratio cannot be increased, and the polarizing performance of the obtained polarizing film is lowered. On the other hand, when the thickness of the PVA film exceeds 100 μm, the polarization performance is not improved and it is not economical, and it is necessary to increase the tension for stretching.
[0029]
The length of the PVA film is 1000 m or more, preferably 1300 m or more, more preferably 2000 m or more, and most preferably 2300 m or more. The upper limit of the length is not particularly limited, but is preferably 10,000 m or less from the viewpoint of handleability. If the length is less than 1000 m, the resulting polarizing film has many seams and the loss increases. Furthermore, although the unwinding part and the core part of the film roll are lost because the stretching conditions are not stable, the loss part is constant regardless of the length of the film, so the length yield is also reduced.
[0030]
The cylindrical core around which the PVA film is wound is, for example, cylindrical, and has an outer diameter of 10 cm or more, and most preferably 15 cm or more. When the outer diameter of the core is less than 10 cm, the core is bent and the PVA film tends to be wrinkled. Further, although there is no particular upper limit on the outer diameter of the core, the film roll diameter becomes larger as the core becomes larger, and an unwinding device larger than necessary is required.
[0031]
Usually, in the PVA film and other plastic films, the length of the core is the same as the film width, but the length of the core around which the PVA film of the present invention is wound is 2 m or more, and it is important that the length is longer than the PVA film width. It is. The length of the core is 2 to 30 cm longer than the PVA film width. When the length of the core is less than 2 cm than the width of the PVA film, the end of the film roll is easily damaged during storage or transportation, and the PVA film is torn from the scratched part during stretching, so stable stretching cannot be performed. . In addition, when the length of the core is longer than 30 cm longer than the width of the PVA film, depending on the material of the core, the film roll tends to bend easily and the PVA film tends to be wrinkled. Necessary. Ideally, the PVA film is wound around the central portion in the length direction of the core, but it may be shifted to one side and wound due to the device. However, both end surfaces of the core need to protrude outside the both end surfaces of the film roll. A jig such as a protective plate may be attached to the end face of the film roll for protecting the end face.
[0032]
Furthermore, it is important that the material of the core is metal or plastic. Examples of the metal include iron and iron alloys such as carbon steel, high-tensile steel, and stainless steel, aluminum and aluminum alloys such as aluminum and duralumin, copper and copper alloys such as copper, brass, and bronze. In addition, a core obtained by laminating soft polyvinyl chloride, low density polyethylene, or the like on these metal cores, or a core plated with nickel, chromium, zinc, tin, or the like can be given. Examples of the plastic include rigid polyvinyl chloride, polypropylene, high density polyethylene, ultrahigh molecular weight polyethylene, polycarbonate, polyester, and polysulfone. Also, films coated with hard polyvinyl chloride, soft polyvinyl chloride, polypropylene, low density polyethylene, high density polyethylene, ultra high molecular weight polyethylene, polycarbonate, polyester, polysulfone, polyvinylidene chloride, aluminum vapor deposition film, alumina vapor deposition film, Examples include a film such as a glass vapor deposition film laminated on the outer surface of various cores (the coated surface or vapor deposition surface may be on the core side or on the anti-core side). When the core in contact with the film is wood, paper or cloth, moisture or plasticizer in the PVA film moves to the core during storage or transportation, the core bends, and wrinkles occur in the PVA film. And since the quantity of the water | moisture content in a PVA film and a plasticizer is reducing, so that it becomes close to a core part, stable extending | stretching cannot be performed.
[0033]
The thickness of the core is 1.5 mm to 20 mm, preferably 2 mm to 15 mm, and most preferably 3 mm to 10 mm. If the thickness of the core is less than 1.5 mm, the film roll may bend due to insufficient strength depending on the material of the core, and the PVA film may be wrinkled, or the core may be deformed and cannot withstand repeated use over a long period of time. On the other hand, when the thickness exceeds 20 mm, the core weight increases depending on the material of the core, and handling difficulty may increase.
[0034]
It is also important to wrap the film roll with a packaging film having a moisture permeability of 10 g / m ² / day or less. The moisture permeability is measured by a method defined in JIS Z 0208. That is, it is a value at a humidity difference of 90% RH and 0% RH at 40 ° C. Moisture permeability of the packaging film is not more than 10 g / m ² / day, preferably 8 g / m ² / day or less, more preferably less 5 g / m ² / day or less, and most preferably 3 g / m ² / day. When the moisture permeability of the packaging film exceeds 10 g / m ² / day, the moisture and plasticizer in the PVA film volatilize or absorb outside air moisture during storage, and the film roll surface and winding cores Since the composition changes, stable stretching cannot be performed.
[0035]
As the packaging film, a laminated film of polyester, aluminum foil and polyethylene, a laminated film of aluminum-deposited polyester and polyethylene, a laminated film of alumina-deposited polyester and polyethylene, a laminated film of glass-deposited polyester and polyethylene, a polyvinylidene chloride-coated polypropylene, Examples thereof include a polyethylene laminated film, a polypropylene film, a high-density polyethylene film, and a low-density polyethylene film. Moreover, the laminated product of these films, a burif, paper, a nonwoven fabric, etc. can be illustrated. Furthermore, the outside of these films and laminates may be packaged with paper or the like, or may be accommodated in a carton box, a wooden box, a metal case, a frame, or the like.
[0036]
When storing or transporting the packaged PVA film roll, it is preferable to avoid extreme high temperature or low temperature conditions or high humidity or low humidity conditions. Specifically, the temperature is 5 to 40 ° C. and the humidity is 30 to 90%. RH is more preferable, temperature is 10 to 30 ° C., and humidity is 40 to 75% RH.
[0037]
In order to produce a polarizing film from the PVA film of the present invention, for example, the PVA film may be dyed, uniaxially stretched, fixed, and dried, and further subjected to heat treatment as necessary. Dyeing, uniaxially stretched, fixed There are no particular restrictions on the order of processing operations. Further, a specific operation may be performed twice or more.
[0038]
Dyeing can be performed before uniaxial stretching, at the time of uniaxial stretching, or after uniaxial stretching. As dyes used for dyeing, iodine-potassium iodide; direct black 17, 19, 154; direct brown 44, 106, 195, 210, 223; direct red 2, 23, 28, 31, 37, 39, 79, 81 , 240, 242, 247; Direct Blue 1, 15, 22, 78, 90, 98, 151, 168, 202, 236, 249, 270; Direct Violet 9, 12, 51, 98; Direct Green 1, 85; Direct Dichroic dyes such as yellow 8, 12, 44, 86, 87; direct orange 26, 39, 106, 107 can be used in one kind or a mixture of two or more kinds. Ordinary dyeing is generally performed by immersing the PVA film in a solution containing the above-mentioned dye, but the processing conditions and processing method are particularly limited, such as mixing with the PVA film to form a film. is not.
[0039]
Uniaxial stretching can be performed by wet stretching or dry heat stretching, and can be performed in the air using warm water (in a solution containing the dye or in a fixing treatment bath described later) or a PVA film after water absorption. The stretching temperature is not particularly limited, but is preferably 30 to 90 ° C. when the PVA film is stretched (wet stretching) in warm water, and 50 to 180 ° C. when it is dry heat stretched. Further, the stretching ratio of uniaxial stretching (total stretching ratio in the case of multi-stage uniaxial stretching) is preferably 4 times or more, more preferably 4.5 times or more, and further preferably 5 times or more from the viewpoint of polarization performance. The upper limit of the stretching ratio is not particularly limited, but it is preferably 8 times or less because uniform stretching is easily obtained. The thickness of the film after stretching is preferably from 3 to 75 μm, more preferably from 5 to 50 μm.
[0040]
Fixing treatment is often performed for the purpose of strengthening the adsorption of the dye to the film. Usually, boric acid and / or boron compounds are added to the treatment bath used for the fixing treatment. Moreover, you may add an iodine compound in a processing bath as needed.
[0041]
The drying treatment (heat treatment) of the PVA film is preferably performed at 30 to 150 ° C, more preferably 50 to 150 ° C.
[0042]
The polarizing film of the present invention obtained as described above is usually used as a polarizing plate by attaching a protective film optically transparent and having mechanical strength on both sides or one side. As the protective film, a cellulose triacetate (TAC) film, an acetic acid / cellulose butyrate (CAB) film, an acrylic film, a polyester film, or the like is used. Examples of the adhesive for bonding include PVA adhesives and urethane adhesives. Among them, PVA adhesives are preferable.
[0043]
【Example】
Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, the dichroic ratio in an Example was evaluated with the following method.
[0044]
Dichroic ratio:
The dichroic ratio was used as an index for evaluating the polarization performance of the obtained polarizing film. This dichroic ratio is a transmittance Ts obtained by measuring and calculating in a C light source and a two-degree field of view using a spectrophotometer in accordance with the Japan Electronic Machinery Manufacturers Association (EIAJ) LD-201-1983. (%) And polarization degree P (%) were used to obtain the following formula.
Dichroic ratio = log (Ts / 100-Ts / 100 × P / 100)
/ Log (Ts / 100 + Ts / 100 × P / 100)
[0045]
Example 1
An aqueous solution containing 100 parts by weight of PVA having a degree of saponification of 99.9 mol% and a degree of polymerization of 1750 and 10 parts by weight of glycerin and having a PVA concentration of 15% by weight was cast to form a film having a width of 2.3 m and a film thickness. A 75 μm thick PVA film was 2200 m long, wound around a cylindrical rigid polyvinyl chloride core having a length of 2.35 m, an outer diameter of 11.4 cm, and a wall thickness of 7 mm to form a film roll. Further, the film roll is double-wrapped with a biaxially stretched polypropylene film (moisture permeability, 7 g / m ² / day) having a thickness of 3.3 m and a thickness of 20 μm as a packaging film, and the remaining portion in the width direction is formed. The package was pushed into the core. The end surface of the package was rubbed against a concrete wall.
[0046]
After the PVA film was stored in a warehouse for six months, a polarizing film was prepared by processing in the order of pre-swelling, dyeing, uniaxial stretching, fixing treatment, drying, and heat treatment. That is, the PVA film was pre-swelled by immersing it in water at 30 ° C. for 5 minutes, and immersed in an aqueous solution at 35 ° C. having an iodine concentration of 0.4 g / liter and a potassium iodide concentration of 40 g / liter for 3 minutes. Subsequently, uniaxial stretching was performed 5.6 times in a 40 ° C. aqueous solution with a boric acid concentration of 4%, and a potassium iodide concentration of 40 g / liter, a boric acid concentration of 40 g / liter, and a zinc chloride concentration of 10 g / liter at 30 ° C. Fixing was performed by immersing in an aqueous solution for 5 minutes. The film was taken out, dried with hot air at 40 ° C. under a constant length, and further heat-treated at 100 ° C. for 5 minutes.
[0047]
The thickness of the obtained polarizing film was 22 μm, and stretching was also smooth. Further, the transmittance was 43.1%, the polarization degree was 98.9%, and the dichroic ratio was 34.7.
[0048]
Example 2
100 parts by weight of PVA having a saponification degree of 99.9 mol% and a polymerization degree of 4000, 10 parts by weight of glycerin and 110 parts by weight of water are melt-kneaded in an extruder, formed into an extrusion film, and dried with a multistage metal roll. As a result, a PVA film having a film width of 2.7 m and a film thickness of 75 μm is made 2600 m in length, wound around a cylindrical stainless steel core having a length of 2.72 m, an outer diameter of 16.52 cm, and a wall thickness of 3.4 mm. It was a roll. Further, the film roll is double-wrapped with a biaxially stretched polypropylene film (moisture permeability, 7 g / m ² / day) of 3.8 m wide and 20 μm thick as a packaging film, and the remaining part in the width direction is The package was pushed into the core. The end surface of the package was rubbed against a concrete wall.
[0049]
After the PVA film was stored in a warehouse for six months, a polarizing film was prepared by processing in the order of pre-swelling, dyeing, uniaxial stretching, fixing treatment, drying, and heat treatment. That is, the PVA film was pre-swelled by immersing it in water at 30 ° C. for 5 minutes, and immersed in an aqueous solution at 35 ° C. having an iodine concentration of 0.4 g / liter and a potassium iodide concentration of 40 g / liter for 3 minutes. Subsequently, uniaxial stretching was performed 5.6 times in a 40 ° C. aqueous solution with a boric acid concentration of 4%, and a potassium iodide concentration of 40 g / liter, a boric acid concentration of 40 g / liter, and a zinc chloride concentration of 10 g / liter at 30 ° C. Fixing was performed by immersing in an aqueous solution for 5 minutes. The film was taken out, dried with hot air at 40 ° C. under a constant length, and further heat-treated at 100 ° C. for 5 minutes.
[0050]
The thickness of the obtained polarizing film was 22 μm, and stretching was also smooth. Further, the transmittance was 43.0%, the polarization degree was 99.7%, and the dichroic ratio was 43.7.
[0051]
Example 3
An aqueous solution containing 100 parts by weight of PVA having a degree of saponification of 99.9 mol% and a degree of polymerization of 1750 and 10 parts by weight of glycerin and having a PVA concentration of 15% by weight was cast to form a film having a width of 2.0 m and a film thickness. A PVA film having a thickness of 50 μm was made 1300 m long, wound around a cylindrical rigid polyvinyl chloride core having a length of 2.005 m, an outer diameter of 11.4 cm, and a thickness of 7 mm to form a film roll. Further, the film roll is double wrapped with a biaxially stretched polypropylene film (moisture permeability, 7 g / m ² / day) having a thickness of 3 m and a thickness of 20 μm as a packaging film, and the remaining portion in the width direction is used as a core. A package was formed by pressing. The end surface of the package was rubbed against a concrete wall.
[0052]
The PVA film was treated in the same manner as in Example 1 to prepare a polarizing film. A single cut occurred during stretching. The thickness of the obtained polarizing film was 15 μm, the transmittance was 45.6%, the polarization degree was 95.5%, and the dichroic ratio was 33.8.
[0053]
Comparative Example 1
In Example 1, except that the length of the core was the same as the film width of the PVA film, processing was performed in the same manner as in Example 1 to obtain a package. The end surface of the package was rubbed against a concrete wall.
[0054]
After the PVA film was stored in a warehouse for six months, it was treated in the same manner as in Example 1. However, the PVA film was frequently cut during the stretching operation and could not be stably stretched.
[0055]
Comparative Example 2
In Example 1, except that the packaging film was a biaxially stretched nylon film having a thickness of 15 μm (moisture permeability, 260 g / m ² / day), a treatment was performed in the same manner as in Example 1 to obtain a package. The end surface of the package was rubbed against a concrete wall.
[0056]
After storing the PVA film in a warehouse for six months, the treatment was performed in the same manner as in Example 1. However, the moisture content changed between the surface portion and the core portion of the film roll, and stable stretching could not be performed.
[0057]
Comparative Example 3
In Example 1, except having changed the width | variety of the PVA film into 1.5 m, it processed similarly to Example 1 and was set as the package. The end surface of the package was rubbed against a concrete wall.
[0058]
After storing the PVA film in a half-year warehouse, the same processing as in Example 1 was performed. The thickness of the obtained polarizing film was 23 μm. The central part of the polarizing film had a transmittance of 42.8%, a polarization degree of 98.7%, and a dichroic ratio of 32.0. When the polarizing film was inserted at 45 ° between polarizing plates in a crossed Nicol state and the transmitted light was visually observed, large optical spots were observed.
[0059]
Comparative Example 4
In Example 2, except that the core was changed to paper, processing was performed in the same manner as in Example 2 to obtain a package. The end surface of the package was rubbed against a concrete wall.
[0060]
The PVA film was stored in a half-year warehouse and then processed in the same manner as in Example 2. Due to the bending of the film roll, wrinkles entered the PVA film and the feeding was not constant. In addition, as the film roll approaches the winding core, the plasticizer has moved to the paper, and the amount of swelling has also overlapped, and stable stretching has not been possible.
[0061]
Comparative Example 5
In Example 2, except that the core was changed to a hard polyvinyl chloride core having an outer diameter of 5 cm and a wall thickness of 3 mm, the same treatment as in Example 2 was performed to obtain a package. The end surface of the package was rubbed against a concrete wall.
[0062]
The PVA film was stored in a half-year warehouse and then processed in the same manner as in Example 2. Due to the bending of the film roll, wrinkles entered the PVA film and the feeding was not constant, and stable stretching could not be performed.
[0063]
Comparative Example 6
In Comparative Example 3, except that the length of the core was changed to 1.45 m, the same process as in Comparative Example 3 was performed to obtain a package. The end surface of the package was rubbed against a concrete wall.
[0064]
After the PVA film was stored in a warehouse for six months, it was treated in the same manner as in Example 1. However, the PVA film was frequently cut during the stretching operation and could not be stably stretched.
[0065]
Comparative Example 7
In Example 3, except that the thickness of the PVA film was changed to 30 μm, the same treatment as in Example 3 was performed to obtain a package. The end surface of the package was rubbed against a concrete wall.
[0066]
The PVA film was processed in the same manner as in Example 3 except that cutting was frequently caused in the uniaxial stretching of 5.6 times in Example 3, so that a polarizing film was prepared in the same manner as in Example 3. The thickness of the obtained polarizing film was 15 μm, the transmittance was 44.6%, the polarization degree was 92.7%, and the dichroic ratio was 22.6.
[0067]
Comparative Example 8
In Example 1, except that the thickness of the PVA film was changed to 150 μm, the same treatment as in Example 1 was performed to obtain a package. The end surface of the package was rubbed against a concrete wall.
[0068]
The PVA film was treated in the same manner as in Example 1 except that the tension of the apparatus was insufficient to perform uniaxial stretching of 5.6 times in Example 1, except that the uniaxial stretching was changed to 4.8 times. A polarizing film was prepared. The thickness of the obtained polarizing film was 45 μm, the transmittance was 41.7%, the polarization degree was 99.4%, the dichroic ratio was 32.5, and there was no effect of improving the polarization performance. .
[0069]
Comparative Example 9
In Example 3, except that the length of the PVA film was changed to 400 m, the same treatment as in Example 3 was performed to obtain a package. The end surface of the package was rubbed against a concrete wall.
[0070]
The PVA film was processed in the same manner as in Example 3 to prepare a polarizing film. The thickness of the obtained polarizing film was 15 μm, the transmittance was 45.6%, the polarization degree was 95.5%, and the dichroic ratio was 33.8. The loss of the unwinding part and the winding core part was uneconomical.
[0071]
【The invention's effect】
As described above, according to the present invention, a PVA film for polarizing film that can be stably stretched and is useful as a raw material for producing a wide polarizing film can be obtained.

Claims (2)

The material is made of metal or plastic, or plastic coated metal or metal-coated plastic. The outer diameter is 10 cm or more, the length is 2 m or more, and the length of the film is 2 cm to 30 cm longer than the film width. A polyvinyl alcohol polymer film having a thickness of 40 μm to 100 μm, a film width of 2 m or more, and a film length of 1300 m or more is wound to form a film roll, and both end faces of the core protrude from both end faces of the film roll within the core length range, respectively. In this state, the film roll is wrapped in a double roll with a packaging film having a moisture permeability of 10 g / m ² / day or less, and stored or transported for a polyvinyl alcohol polymer film for polarizing film that is stored or transported. Method.   The method for storing or transporting a polyvinyl alcohol polymer film for a polarizing film according to claim 1, wherein the core has a thickness of 1.5 mm to 20 mm.