TW201508067A - Polyvinyl alcohol film roll and polarizing film using same - Google Patents

Abstract

Provided is a polyvinyl alcohol film roll which is suited to increase in the width and length of a polyvinyl alcohol film, which delivers a film of a uniform quality, and which is capable of providing a polarizing film that has excellent polarization performance and appearance characteristics. This polyvinyl alcohol film roll is obtained by winding a polyvinyl alcohol film for optical applications around a cylindrical core tube. The core tube is formed of an aluminum alloy, and the aluminum alloy has a copper content of 0.15-0.5% by weight, a manganese content of 0.04-0.8% by weight, a chromium content of 0.01-0.5% by weight and a zinc content of 0.01-0.5% by weight.

Description

Polyvinyl alcohol film roll and polarizing film using the film roll

The present invention relates to a polyvinyl alcohol film roll, and more particularly to a polyvinyl alcohol film roll having a wide and elongated strip of polyvinyl alcohol film, and the use of the film A polarizing film excellent in polarizing performance obtained by reeling.

Polyvinyl alcohol-based films have been used in various applications in the past, and useful examples thereof include optical films, particularly polarizing films.

In general, a polyvinyl alcohol-based film is wound up in a cylindrical core tube after film formation, whereby it is commercialized.

In recent years, in order to increase the size of the liquid crystal display device, it is required to increase the size of the polyvinyl alcohol-based film, in particular, to increase the width of the liquid crystal display device, and further, when a polarizing film is produced using a polyvinyl alcohol-based film, from the viewpoint of productivity. Look, it requires a strip of more than 5000m.

As a core tube of a polyvinyl alcohol-based film which is elongated in a wide strip shape, it is preferable to use a core tube of aluminum from the viewpoint of weight, strength, cost, etc. of the core tube (refer to, for example, Patent Document 1) And 2). [Practical Technical Literature] [Patent Literature]

Patent Document 1: Japanese Laid-Open Patent Publication No. 2004-106377 (Patent Document 2)

[Problems to be solved by the present invention]

In recent years, the large-screening of liquid crystal display devices has been further developed, for example, since 32 吋, and even 52 吋 has rapidly developed. Along with this phenomenon, the polyvinyl alcohol-based film must be further expanded in accordance with the width and the length of the film, and a core tube which is improved in strength and flexur resistance is required in order to be produced by winding it.

Further, the polyvinyl alcohol-based film roll wound around the core tube is usually stored in a suspended state by a core tube portion that supports the outer side of the roll end, but in this case, the core tube is supported. Due to the local force, there are also doubts such as core tube bending and true round deformation. From this point of view, it is more necessary to improve the large-sized core tube. In the case where the core tube is bent or deformed in a true circle, the extraction speed is unstable due to the eccentricity at the time of film extraction due to the deformation of the core tube, and defects such as cracks and dents of the film are caused. Due to this defect, it is also related to the occurrence of optical unequal defects. Further, if the deformation of the true circle is too large, it is impossible to install it in a state of being manufactured.

In view of the above, an object of the present invention is to provide a polyvinyl alcohol-based film roll which can obtain a polarizing film having excellent polarizing performance and appearance characteristics, and which also corresponds to the widening and lengthening of a polyvinyl alcohol film. The extracted film is a homogeneous film. [Technical means to solve the problem]

However, the inventors of the present invention have repeatedly conducted a thorough review in order to achieve this object, and as a result, have found the following contents, and have completed the present invention: attention is paid to the aluminum alloy used for the material of the core tube, if the aluminum alloy has a copper content of 0.15 to 0.5. When the weight %, the manganese content is 0.04 to 0.8% by weight, the chromium content is 0.01 to 0.5% by weight, and the zinc content is 0.01 to 0.5% by weight, the core tube is excellent in deformation resistance and flex resistance. Further, even if the polyvinyl alcohol-based film wound around the core tube is widened and elongated, the polyvinyl alcohol-based film roll composed of the same is excellent in deformation resistance and flex resistance; The film extracted from the polyvinyl alcohol film roll is a homogeneous film, and the polarizing film produced by the film is a polarizing film excellent in polarizing performance and appearance characteristics.

In the first aspect of the present invention, a polyvinyl alcohol-based film roll is obtained by winding an optical polyvinyl alcohol film on a cylindrical core tube, and the core tube is made of an aluminum alloy. The copper content is 0.15 to 0.5% by weight, the manganese content is 0.04 to 0.8% by weight, the chromium content is 0.01 to 0.5% by weight, and the zinc content is 0.01 to 0.5% by weight; and the second object is a polarizing film. It is obtained by using the polyvinyl alcohol-based film extracted from this polyvinyl alcohol-based film roll. [Effect of the present invention]

The polyvinyl alcohol-based film reel of the present invention comprises a core tube made of an aluminum alloy, wherein the aluminum alloy has a copper content of 0.15 to 0.5% by weight, a manganese content of 0.04 to 0.8% by weight, and a chromium content of 0.01 to 0.5 by weight. %, the zinc content is 0.01 to 0.5% by weight. Therefore, even if the core tube is elongated, it is excellent in deformation resistance and flex resistance, and even if the polyvinyl alcohol-based film wound around the core tube is widened and elongated, it can be made Excellent resistance to deformation and flexing. As a result, in the polyvinyl alcohol-based film roll of the present invention, the extracted film can be a homogeneous film, and the polarizing film produced by the film can be a polarizing film excellent in polarizing performance and appearance characteristics.

In particular, when the amount of niobium contained in the aluminum alloy is 0.3 to 1.5% by weight, the deformation resistance and the flex resistance of the core tube can be further improved, and as a result, the polyvinyl alcohol-based film reel can be further improved. Resistance to deformation and flexing resistance.

Further, in the case where the iron content of the aluminum alloy is 0.04 to 0.8% by weight, the magnesium content is 0.2 to 1.5% by weight, and the titanium content is 0.01 to 0.5% by weight, the deformation resistance and the resistance of the core tube can be further improved. Flexibility, and deformation resistance and flex resistance of a polyvinyl alcohol film roll.

In the case where the 0.2% proof stress of the aluminum alloy is 175 N/mm ² or more, even if the core tube is elongated, the flexural resistance can be excellent; even if the polyvinyl alcohol is taken up in the core tube The film is wide and long, and it is still excellent in flex resistance. As a result, in the polyvinyl alcohol-based film roll of the present invention, the extracted film can be a homogeneous film, and the polarizing film produced by the film can be a polarizing film excellent in polarizing performance and appearance characteristics.

Further, since the polarizing film of the present invention uses a homogeneous film extracted from the polyvinyl alcohol film roll of the present invention, it is excellent in polarizing performance and appearance characteristics.

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

An embodiment of the polyvinyl alcohol-based film roll of the present invention comprises: a cylindrical core tube made of an aluminum alloy having a specific component; and a polyvinyl alcohol-based film wound up in the core tube. The outer perimeter.

The composition of the aluminum alloy of the material of the core tube is preferably a combination of copper content of 0.15 to 0.5% by weight, preferably 0.15 to 0.4% by weight; manganese content of 0.04 to 0.8% by weight, preferably It is 0.05 to 0.5% by weight; the chromium content is 0.01 to 0.5% by weight, preferably 0.04 to 0.35% by weight; and the zinc content is 0.01 to 0.5% by weight, preferably 0.04 to 0.25% by weight. The core tube is made into a core tube excellent in deformation resistance and flex resistance by making it a specific component for this purpose. Further, when these components are not contained, the strength of the core tube is lowered, and the deformation resistance and the flex resistance are lowered. Further, too much content of each component tends to make it difficult to obtain the effects of the present invention.

In particular, in the composition of the aluminum alloy, from the viewpoint of further improving the deformation resistance and the flex resistance of the core tube, the preferred aspect is that the amount of cerium is 0.3 to 1.5% by weight, preferably 0.4. ～0.9% by weight. Further, when the content of the monoterpene component is too small, the deformation resistance and the flex resistance of the core tube tend to be lowered, so the content thereof is particularly preferably more than 0.5% by weight.

Further, among the components of the above aluminum alloy, preferred embodiments are as follows: the iron content is 0.04 to 0.8% by weight, preferably 0.1 to 0.7% by weight; the magnesium content is 0.2 to 1.5% by weight, preferably 0.4 to 1.2% by weight; the amount of titanium is 0.01 to 0.5% by weight, preferably 0.04 to 0.15% by weight.

Further, in the core tube used in the present invention, it is preferable to use an aluminum alloy having the above composition from the viewpoint of excellent deformation resistance and flex resistance of the core tube, and the 0.2% proof resistance of the aluminum alloy is 175 N/mm ² or more. . The above suitable range of 0.2% proof stress is 175 to 600 N/mm ² , and particularly preferably 200 to 400 N/mm ² .

The size of the above-mentioned core tube varies depending on the width of the polyvinyl alcohol-based film to be taken up, and the outer diameter thereof is generally in the range of 150 to 300 mm, preferably in the range of 160 to 260 mm, and the cylinder. The length (length in the axial direction) is generally in the range of 2 to 7 m, preferably in the range of 3 to 6 m. Further, the wall thickness of the core tube is generally preferably in the range of 3 to 40 mm, particularly preferably 5 to 30 mm, and more preferably 6 to 20 mm. Further, the mass of the above-mentioned core tube is generally in the range of 15 to 500 kg, particularly preferably in the range of 30 to 150 kg.

The core tube used in the present invention is an aluminum alloy containing the respective components as described above, and can be produced, for example, as follows. That is, the ingot of the aluminum alloy containing the above components is heated to a general temperature of 400 to 600 ° C, and then extruded from a die under a high pressure environment to form a cylinder. There is an aluminum alloy extruded at a high temperature, and after further returning to normal temperature, the temperature is again raised to 170 to 180 ° C, and the temperature is raised and stored for 5 to 10 hours to perform artificial age hardening treatment, or after high temperature extrusion. It is quenched (quenched) by means of artificial age hardening.

On the other hand, the above polyvinyl alcohol-based film is produced, for example, as follows. That is, the film is formed by casting using a polyvinyl alcohol-based resin aqueous solution.

As the polyvinyl alcohol-based resin, an undenatured polyvinyl alcohol-based resin, that is, a resin obtained by saponifying polyvinyl acetate obtained by polymerizing vinyl acetate, is generally used. If necessary, a resin obtained by saponifying a copolymer of vinyl acetate and a small amount (for example, 10 mol% or less, preferably 5 mol% or less) copolymerizable with vinyl acetate may be used. Examples of the component copolymerizable with vinyl acetate include an unsaturated carboxylic acid (including a salt, an ester, a guanamine, a nitrile, etc.) and an olefin having 2 to 30 carbon atoms (ethylene, propylene, n-butene, isobutylene, etc.). , vinyl ethers, unsaturated sulfonates, and the like.

Further, as the polyvinyl alcohol-based resin, a polyvinyl alcohol-based resin having a 1,2-alcohol bond in its side chain can be used. The polyvinyl alcohol-based resin having a 1,2-alcohol bond in the one side chain can be obtained, for example, by the following methods: (i) vinyl acetate and 3,4-diethyloxy-1-butane a method for saponifying a copolymer of an alkene; (ii) a method for saponifying and decarboxylating a copolymer of vinyl acetate and ethylene carbonate; (iii) a vinyl acetate with 2,2-dialkyl-4-ethylene- a method of saponification and deketalization of a copolymer of 1,3-dioxolane; (iv) a method of saponifying a copolymer of vinyl acetate and glycerol monoallyl ether.

The weight average molecular weight of the polyvinyl alcohol-based resin is preferably from 80,000 to 300,000, more preferably from 110,000 to 260,000, still more preferably from 130,000 to 200,000. When the weight average molecular weight is too small, when the polyvinyl alcohol-based resin is used as an optical film, sufficient optical performance tends not to be obtained. When the film is too large, stretching becomes difficult when the film is used as a polarizing film. It is difficult to carry out industrial production. Further, the weight average molecular weight of the polyvinyl alcohol-based resin is measured by the GPC-LALLS method.

Further, the average saponification degree of the polyvinyl alcohol-based resin is preferably 80 mol% or more, more preferably 85 to 100 mol%, particularly preferably 98 to 100 mol%. As described above, when the average degree of saponification is too small, it is difficult to obtain sufficient polarizing performance when it is used as a polarizing film.

The aqueous solution of the polyvinyl alcohol-based resin generally contains a plasticizer generally used such as glycerin, diglycerin, triglycerin, ethylene glycol, triethylene glycol, polyethylene glycol, or trimethylolpropane, and the content thereof is relatively The polyvinyl alcohol-based resin is preferably 30% by weight or less, particularly preferably 3 to 25% by weight, more preferably 5 to 20% by weight. If the amount of the above plasticizer is too large, the film strength tends to decrease.

Further, it is preferable to contain a nonionic, anionic or cationic surfactant, and it is particularly preferable to contain a nonionic surfactant such as polyoxyethylene alkylamine ether. The content of the surfactant is preferably 5% by weight or less, more preferably 0.001 to 3% by weight, particularly preferably 0.001 to 2% by weight based on the polyvinyl alcohol-based resin. If the amount of the above surfactant is too large, the appearance of the surface of the film tends to be poor.

The sodium acetate contained in the powder of the polyvinyl alcohol-based resin adversely affects the optical properties, so it is preferable to remove it (de-vinegar). The removal (de-vinegar) of the sodium monoacetate is generally carried out by adding water to the polyvinyl alcohol-based resin in a vinegar tank.

Next, the washed aqueous polyvinyl alcohol-based resin wet cake is dissolved to prepare a polyvinyl alcohol-based resin aqueous solution, and the desired high concentration cannot be obtained by directly dissolving the aqueous polyvinyl alcohol-based resin wet cake in water. The aqueous solution should be dehydrated first. The dehydration method is not particularly limited, but is generally a method using centrifugal force. In a preferred embodiment, the aqueous polyvinyl alcohol-based resin wet cake having a water content of 50% by weight or less, preferably 30 to 45% by weight, is prepared by the above-mentioned washing and dehydration. If the water content is too high, there is a tendency that it becomes difficult to become a desired aqueous solution concentration.

Then, in the dissolution tank, water vapor (about 110 to 160 ° C) is blown into the cake-shaped polyvinyl alcohol-based resin, and the mixture is pressurized and dissolved to prepare a polyvinyl alcohol-based resin aqueous solution. At this time, a plasticizer or an additive is added as necessary. Thereby, a polyvinyl alcohol-based resin aqueous solution having a water content of about 60 to 80% by weight is obtained.

Then, the obtained polyvinyl alcohol-based resin aqueous solution was filtered to remove impurities, and then degassed. As the degassing treatment method, a degassing treatment method or the like produced by using a static degassing or a multiaxial extruder is preferably a degassing treatment method using a multiaxial extruder.

Next, the degassed polyvinyl alcohol-based resin aqueous solution was again filtered, and then supplied to a T-slot die, which was extruded from a T-slot die and slid down on a screen.

Thereafter, the polyvinyl alcohol-based resin aqueous solution which is extruded from the T-slot die is cast, formed, and dried on the outer peripheral surface of the rotating drum roll to form a film. Further, in order to form and dry the above film, the drum type drum usually has a high temperature (about 80 to 100 ° C).

Next, the film is peeled off from the outer peripheral surface of the drum reel so that the surface and the back surface of the film are passed through a plurality of drying rolls (about 60 to 100 ° C), and a heat treatment machine (100 ~) is preferably used. 140 ° C degree). Then, use the humidity regulator as necessary. The moisture content of the film is preferably 5% by weight or less, particularly preferably from 1 to 4% by weight. When the water content is too high, there is a tendency that the appearance is poor when the film is stored. Thus, a polyvinyl alcohol-based film required for the purpose was obtained. The size of the obtained polyvinyl alcohol-based film is generally set to a width of 1.5 to 6 m and a length of 5,000 to 20,000 m.

Thereafter, the core tube made of an aluminum alloy having a specific composition was attached to a coiler. Next, the coiler was driven to rotate the core tube, and the obtained polyvinyl alcohol-based film was wound up on the outer peripheral surface of the core tube. Here, the core tube is made of an aluminum alloy made of an aluminum alloy having a specific component and having an endurance of 175 N/mm ² or more as described above, and has high strength, deformation resistance, and flex resistance. Since the core tube is excellent in rotation, when the core tube is rotated by the above-mentioned coiler, the rotation vibration of the core tube is small, and the polyvinyl alcohol-based film can be wound up in a homogeneous state such as wrinkle-free. Then, if necessary, the coiled polyvinyl alcohol film was cut by the slitter at the product width width, and was again taken up in the core tube. Thus, the polyvinyl alcohol-based film roll of the present embodiment can be obtained. Further, in the present invention, in the state of being stored and transported as a product, it is preferable to use the core tube as a core tube of a polyvinyl alcohol-based film roll, and to have a step of rewinding after the slitter, In the conventional coiling, if the core tube having high strength, high deformation resistance, and high flex resistance is used, it is not necessary to use the above-mentioned core tube, and it is possible to appropriately use the aluminum tube different from the above. Core tube or iron core tube, etc.

Here, when a polyvinyl alcohol-based film is wound up to produce a film roll, a preferred embodiment is, for example, a coiling speed of the core tube of 30 to 100 m/min, preferably 40 to 80 m/min; For the fixed tension control mode; the torque is 20 ~ 200N / m.

The polyvinyl alcohol-based film roll thus obtained is moved to the support table to support the left and right end portions of the core tube. Since the core tube is excellent in deformation resistance and flex resistance as described above, the polyvinyl alcohol-based film reel is formed by winding the polyvinyl alcohol-based film on the core tube, and the deformation resistance and the flex resistance are also improved. It is excellent, supported, stored or transported in a state free from deformation, deflection, or deformation and deflection.

Further, the polyvinyl alcohol-based film of the polyvinyl alcohol-based film roll is very useful as an optical film, particularly a material for forming a polarizing film. Therefore, an example of a method for producing a polarizing film using the polyvinyl alcohol-based film will be described below.

First, the polyvinyl alcohol film roll is attached to the polarizing film manufacturing apparatus from the above-mentioned support stand. Then, the polyvinyl alcohol-based film was taken out from the polyvinyl alcohol-based film roll. At this time, as described above, deformation or deflection of the polyvinyl alcohol-based film roll does not occur. Therefore, when the polyvinyl alcohol-based film is taken out, the rotational vibration of the polyvinyl alcohol-based film roll is small, and the poly-copolymer can be aggregated. The vinyl alcohol-based film is taken out in a homogeneous state such as wrinkle-free or fracture. Then, the polyvinyl alcohol-based film was subjected to dyeing, uniaxial stretching, and boride treatment.

The dyeing is carried out by bringing the polyvinyl alcohol-based film into contact with a liquid containing iodine or a dichroic dye. In general, using an aqueous solution of iodine-potassium iodide, the concentration of iodine is preferably 0.1 to 20 g/L, the concentration of potassium iodide is 10 to 70 g/L, and the weight ratio of potassium iodide to iodine is potassium iodide/iodine = 10 to 100. . Further, the dyeing time is practically about 30 to 500 seconds, and the temperature of the dyeing treatment bath is preferably 5 to 60 °C. In addition to the aqueous solvent, a small amount of an organic solvent compatible with water may be used. Further, as the contact means, any means such as dipping, coating, spraying, or the like can be applied.

The above uniaxial extension is preferably extended to 3 to 10 times, more preferably 3.5 to 6 times. At this time, it is also possible to perform a plurality of extensions in the direction perpendicular to the uniaxial extension (prevention of the extent of the contraction in the width direction or the extension thereof). The temperature condition at the time of uniaxial stretching should be set to a range of 40 to 170 °C. Further, the uniaxial stretching ratio may be finally set to the above range, and the uniaxial stretching operation may be carried out not only in a single stage but also in any stage of the process.

Further, the dyeing may be carried out before the uniaxial stretching, and may be carried out simultaneously with the uniaxial stretching or after the uniaxial stretching, but the polyvinyl alcohol-based film is deteriorated in dyeability due to crystallization by uniaxial stretching. Therefore, the above dyeing should be carried out before or at the same time as the uniaxial stretching.

The boride treatment is used for the treatment of strengthening the dyeing, after the dyeing and uniaxial stretching, or simultaneously with dyeing or simultaneously with uniaxial stretching. As the above boride, boric acid and borax are actually used. The monoboride is used as an aqueous solution or a water-organic solvent mixture at a concentration of 0.3 to 2 mol/L, and it is practically preferable to coexist a small amount of potassium iodide in the liquid. As a treatment method for the above-described boride, it is preferably a dipping method, and a coating method or a spraying method may be applied. Further, as the processing conditions, it is preferred to have a temperature of about 40 to 70 ° C and a treatment time of 2 to 20 minutes, and it is also necessary to carry out the stretching operation during the treatment as necessary.

In the polarizing film obtained as described above, the polyvinyl alcohol-based film which is a material of the polarizing film is extracted from the polyvinyl alcohol-based film roll in a homogeneous state such as no wrinkles or breakage, and thus the polarizing property, Excellent appearance.

Then, the polarizing film may be laminated and bonded as a polarizing plate by laminating an optically isotropic polymer film or sheet as a protective film on one or both sides. Examples of the protective film include cellulose triacetate, cellulose diacetate, polycarbonate, polymethyl methacrylate, polystyrene, polyether oxime, polyaryl aryl ester, and poly-4-methyl pentane. A film or sheet of a polyolefin such as an alkene, a polyphenylene ether, a ring system or a norbornene-based polyolefin. In addition, in order to reduce the thickness of the protective film, the protective film may be replaced with a curable resin such as a urethane resin, an acrylic resin or a urea resin on one or both sides of the polarizing film and stacked thereon. .

Further, the polarizing film (or a film having a protective film or a curable resin laminated on at least one side thereof) may have a transparent pressure-sensitive adhesive layer formed by a general method on one surface thereof. The actual application situation. As the pressure-sensitive adhesive layer, for example, an acrylate such as butyl acrylate, ethyl acrylate, methyl acrylate or 2-ethylhexyl acrylate, and acrylic acid, maleic acid, itaconic acid, or methacrylic acid are used. An adhesive layer mainly composed of a copolymer of an α-monoolefin carboxylic acid such as crotonic acid (a copolymer containing an ethylene monomer such as acrylonitrile, vinyl acetate or styrene), which does not hinder the polarizing property of the polarizing film. Particularly suitable. In addition, it can be used as a pressure-sensitive adhesive having transparency, and for example, a polyvinyl ether type or a rubber type can be used.

The polarizing film thus obtained can be used, for example, in a liquid crystal display device such as a liquid crystal display (electronic desktop computer, electronic timepiece, word processor, personal computer, portable information terminal, automobile, or mechanical type). ), sunglasses, anti-glare glasses, 3D glasses, display elements (CRT, LCD, etc.) for reducing reflective layers, medical equipment, building materials, toys, etc. [Examples]

In the following, the present invention will be more specifically described by the examples, and the present invention is not limited by the following examples without departing from the scope of the invention. In addition, the "parts" and "%" in the examples refer to the weight basis.

[Example 1] After the core tube and the polyvinyl alcohol-based film were produced as described below, a polyvinyl alcohol-based film was wound around the outer surface of the core tube to prepare a polyvinyl alcohol-based film roll. Next, a polyvinyl alcohol-based film of the polyvinyl alcohol-based film roll was used to prepare a polarizing film.

[Core tube] As an aluminum alloy having a specific component as described in the above embodiment and an endurance of 0.2%, A6N01 specified in JIS was selected and used as a material to prepare a cylindrical core tube. The chemical composition of the aluminum alloy A6N01 is shown in the following Table 1, and the above-mentioned 0.2% proof is shown in Table 2 below. The size of the core tube is 215 mm in outer diameter, 3500 mm in cylinder length, and 6 mm in wall thickness. In addition, the core tube has a mass of 37 kg.

[0.2% endurance test] In addition, the above 0.2% proof stress was obtained as follows. That is, the measurement of 0.2% endurance is based on JIS Z2241 "Metal Material Tensile Test Method". Further, the test piece was produced by cutting a test piece classified into No. 14 No. B from a cylindrical core tube in accordance with JIS Z2201 "Metal Material Tensile Test Piece". The tensile test was carried out using an AUTOGRAPH AG-X (100 kN) manufactured by Shimadzu Corporation at a tensile speed of 5 mm/min. According to the measurement data, the stress at the strain of 0.2% applied to the self-stress strain curve was 0.2%.

[Polyvinyl alcohol-based film] 100 parts of polyvinyl alcohol having a weight average molecular weight of 135,000 and a degree of saponification of 99.7 mol%, 12 parts of glycerin as a plasticizer, and a polyoxyethylene alkylamino ether as a surfactant (release agent) 0.1 part, and a 35% aqueous solution of polyvinyl alcohol (plasticizer, release agent is also contained as a solid component) is prepared, and then a film is cast from a T-slot die by a drum type roll, and drying and heat treatment are performed. A polyvinyl alcohol-based film having a water content of 4%, a width of 3000 mm, and a thickness of 75 μm was produced by adjusting the humidity.

[Preparation of a polyvinyl alcohol-based film roll] Then, the polyvinyl alcohol-based film 10000 m was wound up on the outer peripheral surface of the above-mentioned core tube. At this time, the winding tension (the tensile force per width of 1 m of the polyvinyl alcohol-based film) was 130 N/m, and the winding speed was 80 m/min. The quality of the wound polyvinyl alcohol film roll was 3000 kg.

[Preparation of polarizing film] After that, the wound polyvinyl alcohol film was taken out at a rate of 1.23 m/min, and swelled in a water washing tank (24 ° C), and then iodine (20 ° C, iodine 0.17 g / L) A 1.8-fold uniaxial extension was performed, and a uniaxial extension of 2.0 times was carried out in a boric acid tank (50 ° C, iodine 8 ppm, boric acid 47 g/L), and a 5.2-fold uniaxial extension was further performed at a take-up speed of 6.4 m/min. , and made a polarizing film.

[Example 2] In the above Example 1, the thickness of the core tube was set to 8 mm. The core tube has a mass of 50 kg. Other than this, it is the same as the above-described first embodiment.

[Example 3] As an aluminum alloy having the specific component of the above-described embodiment and an endurance of 0.2%, A6061 specified in JIS was selected and used as a material to prepare a cylindrical core tube. This 0.2% proof stress was obtained in the same manner as in the above Example 1. Further, the chemical composition of the aluminum alloy A6061 is shown in Table 1 below, and the above-mentioned 0.2% proof is shown in Table 2 below. The size of the core tube is 233 mm in outer diameter, 4800 mm in cylinder length, and 15 mm in wall thickness. Further, the core tube has a mass of 133 kg. A polyvinyl alcohol-based film having a width of 4,500 mm and a thickness of 60 μm was produced as a polyvinyl alcohol-based film wound around the core tube. Further, the quality of the polyvinyl alcohol film roll was 3,600 kg. Other than the above, the same as the above-described first embodiment

[Comparative Example 1] In the above-described Example 1, a core tube made of aluminum alloy A6063 prescribed by JIS was prepared. The chemical composition of the aluminum alloy A6063 is shown in Table 1 below, and the above-mentioned 0.2% proof is shown in Table 2 below. This 0.2% proof stress was obtained in the same manner as in the above Example 1. In addition, the core tube has a mass of 37 kg. Further, the mass of the polyvinyl alcohol film roll was 3,000 kg. Other than this, it is the same as the above-described first embodiment.

[Comparative Example 2] In the above-described Example 3, a core tube made of aluminum alloy A6063 prescribed by JIS was prepared. The chemical composition of the aluminum alloy A6063 is shown in Table 1 below, and the above-mentioned 0.2% proof is shown in Table 2 below. This 0.2% proof stress was obtained in the same manner as in the above Example 1. Further, the core tube has a mass of 133 kg. In addition, the mass of the polyvinyl alcohol film roll was 3,600 kg. Other than this, it is the same as Embodiment 3 described above.

[Flexing of the self-weight of the polyvinyl alcohol-based film roll] The deflection of the self-weight of the polyvinyl alcohol-based film roll of the above Examples 1 to 3 and Comparative Examples 1 and 2 (the deflection of the center portion when the both ends of the pin are supported) ). This result is recorded in Table 2 below.

[Presence or absence of wrinkles in the case of winding a polyvinyl alcohol-based film] The presence or absence of wrinkle formation of each polyvinyl alcohol-based film at the time of winding was visually observed. As a result, the person who did not confirm the wrinkles was evaluated as having a good homogeneity, and was evaluated as ○, and it was confirmed that the crease was formed to be poor in homogeneity, and was evaluated as ×, and recorded in Table 2 below. .

[Scratch of the polarizing film and presence or absence of uneven dyeing] The scratch of the polarizing film and the uneven dyeing were visually observed. As a result, those who did not confirm the scratches and the dyeing unevenness were excellent in appearance characteristics, and were evaluated as ○, and it was confirmed that the product of either of them was evaluated as ×, and was recorded as Table 2 below.

[Optical Characteristics of Polarizing Film] The optical characteristics (single transmittance and degree of polarization) of the polarizing film were measured using "VAP-7070" manufactured by JASCO Corporation. In this measurement, five points were measured at equal intervals in the width direction of the polarizing film, and the maximum value, the minimum value, and the average value thereof were recorded in Table 2 below. Further, in the polyvinyl alcohol films of Comparative Examples 1 and 2, wrinkles were generated, and when the polarizing film was used, uneven dyeing occurred. Therefore, in the film surface, there is a case where the transmittance and the degree of polarization of the monomer are high or low, and it is impossible to form a uniform film.

【Table 2】

From the results of the above Table 2, in Examples 1 to 3, the polyvinyl alcohol-based film did not wrinkle, and the polarizing film did not cause scratches or uneven dyeing. On the other hand, in Comparative Examples 1 and 2, the polyvinyl alcohol-based film was wrinkled, and the extraction of the polyvinyl alcohol-based film was unstable, and uniform stretching was not possible. Therefore, uneven dyeing occurs. It is understood that the reason is due to the self-weight deflection of the polyvinyl alcohol-based film roll of the comparative example, which is larger than that of Examples 1 to 3. Further, in the optical characteristics (single transmittance and degree of polarization) of the polarizing film, in Examples 1 to 3, the difference in the width direction was small, and the in-plane uniformity was excellent. This result can increase the yield and can correspond to the quality of the wide product. On the other hand, in Comparative Examples 1 and 2, since the difference in the width direction was large, the yield was lowered and it was not possible to correspond to a wide product. For this reason, the self-weight deflection of the polyvinyl alcohol-based film roll of Comparative Examples 1 and 2 was also larger than that of Examples 1 to 3.

[Compression test] A test piece composed of an aluminum alloy constituting the core tubes of the above-described Examples 1 and 2 and Comparative Example 1 (width: 40 mm, thickness is the wall thickness of each example (Example 1 and Comparative Example 1: 6 mm; Example 2: 8 mm)] Three samples were prepared, and each test piece was subjected to a compression test under the following conditions using a tensile compression tester (100KN manufactured by INSTRON Co., Ltd.). Then, the load at a displacement of 50 mm was measured, and the average value of the three test pieces was calculated. Bending speed: 10mm/min Test temperature: 23°C Using force side: 100kN Compression distance: 80mm

As a result, the average value of the load at the time of the displacement of 50 mm was: 3873 N for the test piece of Example 1, 6357 N for the test piece of Example 2, and 1797 N for the test piece of Comparative Example 1. That is, the compression strength at the time of the above displacement of 50 mm was found to be about 2.2 times that of the test piece of Comparative Example 1 and the test piece of Example 2 was about 3.5 times.

In the above embodiments, the specific embodiments of the present invention are shown, but the above embodiments are merely illustrative and not intended to be limiting. Various modifications apparent to those skilled in the art are intended to be within the scope of the invention. [Industrial use]

In the present invention, even when the polyvinyl alcohol-based film is made wider and longer, it is possible to obtain a polarizing film having excellent polarizing performance and appearance characteristics from the film.

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Claims (6)

A polyvinyl alcohol-based film roll comprising a polyvinyl alcohol-based film for optical winding in a cylindrical core tube, wherein the core tube is made of an aluminum alloy, and the copper content of the aluminum alloy is 0.15 to 0.5% by weight; manganese content is 0.04 to 0.8% by weight; chromium content is 0.01 to 0.5% by weight; and zinc content is 0.01 to 0.5% by weight. The polyvinyl alcohol-based film reel according to claim 1, wherein the aluminum alloy has a cerium content of 0.3 to 1.5% by weight. The polyvinyl alcohol-based film reel according to claim 1 or 2, wherein the aluminum alloy has an iron content of 0.04 to 0.8% by weight; the magnesium content is 0.2 to 1.5% by weight; and the titanium content is 0.01 to 0.5% by weight or less. A polyvinyl alcohol-based film roll according to claim 1 or 2, wherein the aluminum alloy has a 0.2% proof stress of 175 N/mm ² or more. The polyvinyl alcohol-based film reel according to claim 1 or 2, wherein the core tube has an outer diameter of 150 to 300 mm, and the core tube has a cylinder length of 2 to 7 m. A polarizing film obtained by using a polyvinyl alcohol-based film obtained by a polyvinyl alcohol-based film roll according to any one of claims 1 to 5.