KR20200003279A - Polyvinyl alcohol film roll - Google Patents

Abstract

A roll in which a PVA film having a thickness of 45 µm or less and a length of 2,000 m or more is wound, wherein an average interval between neighboring films is 5 µm or less; And as a manufacturing method of the roll in which the PVA film whose thickness is 45 micrometers or less and length is 2,000 m or more is wound, the touch winding system is employ | adopted and the pressure between a film roll and a contact roll is 1 m in the axial direction of the said film roll. It is 3-30 N per sugar, and it is set as the manufacturing method whose winding speed is 30 m / min or less. Thereby, even when the PVA film is thin and the winding length is long, wrinkles and eccentricity are hardly generated, and a roll of PVA film having a good appearance shape is provided.

Description

Polyvinyl Alcohol Film Roll {POLYVINYL ALCOHOL FILM ROLL}

The present invention relates to a roll of a polyvinyl alcohol film having a good appearance and a process for producing the roll.

A polarizing plate which is a basic component of a liquid crystal display (LCD) such as a liquid crystal television or a liquid crystal monitor is generally dyed in a polyvinyl alcohol film (hereinafter, “polyvinyl alcohol” may be abbreviated as “PVA”). After performing axial stretching and fixing treatment with a boron compound etc. as needed and manufacturing a polarizing film, bonding a protective film, such as a cellulose triacetate (TAC) film, to the surface of the obtained polarizing film, Are manufactured.

In recent years, LCDs have become larger and thinner. As a means of achieving thinning of the LCD, a method of thinning the glass used therein can be considered. In the case where the glass is thinned, the polarizing plate needs to be thinned to reduce the shrinkage stress of the polarizing plate. Therefore, it is required to manufacture a thin polarizing film using a thinner PVA film (for example, refer patent document 1).

The PVA film is usually stored or transported in the form of a roll in which a long PVA film is wound around a cylindrical core (see Patent Document 2, etc.). In order to continuously manufacture what is excellent in the uniformity of optical performance even in a large area polarizing plate continuously with favorable efficiency, the roll of the PVA film which is wider, the winding length is long, and is excellent in quality is calculated | required. PTL 2 is a method of winding a PVA film between the guide roll and the core pipe additionally formed in the cylindrical core pipe, and winding the PVA film into the cylindrical core pipe, wherein the guide roll and the cylindrical core pipe maintain a gap. The method of winding up in the installed non-contact state or the state where the said guide roll and the said cylindrical core pipe contacted through the said PVA film is described. However, when the PVA film was thinner and the winding length was long, fine wrinkles and eccentricity of the center of gravity of the roll were shifted to produce a roll having a good appearance. When using such a roll of PVA film as a raw material, the fluctuation | variation generate | occur | produced at the time of unwinding of a PVA film, and the uniformity of the said PVA film was impaired, and it became a problem.

International Publication No.2014 / 050697 Japanese Unexamined Patent Publication No. 2004-106376

This invention is made | formed in order to solve the said subject, Even if the PVA film is thin and the winding length is long, wrinkles and an eccentricity do not generate | occur | produce well, but it aims at providing the roll of PVA film with favorable external shape.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining in order to solve the said subject, the present inventors find out that the said subject is solved by making the space | interval (thickness of an air layer) between PVA films wound on a roll into a specific range, and based on the said knowledge further, As a result of repeated studies, the present invention was completed.

That is, the present invention,

[1] a roll in which a PVA film having a thickness of 45 µm or less and a length of 2,000 m or more is wound, wherein an average interval between neighboring films is 5 µm or less;

[2] the roll according to the above [1], wherein a width of the PVA film is 2 m or more;

[3] The roll according to the above [1] or [2], wherein the content rate of the plasticizer in the polyvinyl alcohol film is 1 to 30% by mass;

[4] The roll according to any one of the above [1] to [3], wherein the content rate of the surfactant in the polyvinyl alcohol film is 0.01 to 1.0 mass%;

[5] The roll according to any one of the above [1] to [4], wherein the polyvinyl alcohol film has a width of 2 m or more;

[6] the roll according to any one of the above [1] to [5], wherein the PVA film is a raw film for optical film production;

[7] The roll according to the above [6], wherein the optical film is a polarizing film;

[8] A method for producing a roll, in which a polyvinyl alcohol film having a thickness of 45 m or less and a length of 2,000 m or more is wound;

(a) In the winding-up process of a polyvinyl alcohol film, the polyvinyl alcohol film making contact with the outer peripheral surface of the film roll formed from the polyvinyl alcohol film wound up already, making the contact roll arrange | positioned substantially parallel with respect to the axial direction of the said film roll. Winding up,

(b) the pressure between the film roll and the contact roll is 3 to 30 N per 1 m in the axial direction of the film roll,

(c) the manufacturing method whose winding speed is 30 m / min or less;

[9] The method for producing the above [8], wherein the winding tension is 80 N or less per 1 m of the length in the axial direction of the film roll;

[10] The production method according to the above [8] or [9], wherein the parallelism A between the axis of the film roll and the axis of the contact roll obtained at the distance between the axis of the film roll and the axis of the contact roll is 0.7 mm or less;

[11] The parallelism B between the axis of the film roll and the axis of the contact roll when the film roll and the contact roll are viewed in the horizontal direction, which is determined from the horizontal degree of the axis of the film roll and the axis of the contact roll, is 0.2 mm or less. 8]-the manufacturing method in any one of [10];

[12] The production method according to any one of [8] to [11], wherein the average interval between neighboring films in the roll in which the polyvinyl alcohol film is wound is 5 µm or less;

It is about.

According to this invention, even if the PVA film is thin and a winding length is long, the roll of the PVA film with favorable external appearance shape is provided. According to the manufacturing method of this invention, such a roll can be manufactured efficiently.

1 is a schematic view showing an example of a touch winding system.
2 is a schematic view showing an example of a near winding method.
FIG. 3 shows the film roll 1 viewed from the direction 11 of the tangential line 10 of the contact roll 2 in the position where the contact roll 2 is in contact with the film roll 1 in FIG. 1. It is an example of schematic diagram of the contact roll 2.
FIG. 4 is an example of a schematic diagram of the film roll 1 and the contact roll 2 viewed in the horizontal direction 12 in FIG. 1.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail. As for the roll of this invention, the PVA film whose thickness is 45 micrometers or less and whose length is 2,000 m or more is wound up. And in the roll of this invention, the average space | interval between neighboring films is 5 micrometers or less.

When winding up a PVA film and obtaining the roll of this invention, it is preferable to wind up a PVA film in a cylindrical core from a viewpoint of the quality, handleability, etc. of the roll obtained. There is no restriction | limiting in particular in the kind of cylindrical core, For example, a thing made of metal, a thing made of plastic, a thing made of paper, a thing made of wood, etc. are mentioned. The core of the composite can also be used, such as both metal and plastic used, both metal and paper used, and both plastic and paper used. Among them, metals and / or plastics have high strength, the effect of the present invention is more remarkably obtained, and the degree of oscillation that tends to be a problem in the production of optical films such as polarizing films is also low. The core of metal is preferable, and the metal core is more preferable at the point which is hardly affected by abrasion etc. even if it uses repeatedly. It is preferable that the ratio which the mass of a metal and a plastic occupies with respect to the total mass of a cylindrical core is 50 mass% or more, It is more preferable that it is 80 mass% or more, It is further more preferable that it is 95 mass% or more, It is 100 mass% Particularly preferred.

As said metal, iron, stainless steel, aluminum etc. are mentioned, for example, You may use individually by 1 type and may use 2 or more types together. Among these, aluminum and iron are preferable from a viewpoint of strength, light weight, price, and the like.

Moreover, as said plastic, polyvinyl chloride, polyvinylidene chloride, polyester, a polycarbonate, a polyamide, an epoxy resin, a polyurethane, a polyurea, a silicone resin etc. are mentioned, for example, 1 type of these is mentioned. May be used independently and may use 2 or more types together. Among these, polyvinyl chloride is preferable. It is also preferable that the said plastic is fiber reinforced plastics (FRP), such as carbon fiber reinforced plastics, from a viewpoint of strength.

Although there is no restriction | limiting in particular in the length of a cylindrical core, From a viewpoint of handleability etc., it is preferable that a winding is longer in the range of 5-100 cm than the width of a PVA film, and it is longer in the range of 10-45 cm It is preferable and it is more preferable that it is long in the range of 15-30 cm.

Although there is no restriction | limiting in particular in the diameter of a cylindrical core, From an viewpoint of strength, handleability, etc., it is preferable that the outer diameter exists in the range of 50-800 mm, It is more preferable to exist in the range of 80-500 mm, More preferably, it is 100-300 It is more preferable to exist in the range of mm, and it is especially preferable to exist in the range of 150-250 mm. In addition, the thickness of the cylindrical core is preferably in the range of 2 to 50 mm, more preferably in the range of 3 to 20 mm, more preferably in the range of 4 to 10 mm from the viewpoint of strength, handleability, and the like. desirable.

As PVA constituting the PVA film used in the present invention, for example, modified PVA obtained by saponifying a polyvinyl ester obtained by polymerizing a vinyl ester, modified PVA obtained by graft copolymerization of a comonomer to the main chain of PVA, vinyl So-called polyvinyl acetal resins obtained by crosslinking a hydroxyl group of modified PVA, unmodified PVA, or modified PVA obtained by saponifying a modified polyvinyl ester obtained by copolymerizing an ester and a comonomer with aldehydes such as formalin, butylaldehyde, and benzaldehyde, etc. Can be. When PVA which comprises a PVA film is modified PVA, it is preferable that it is 15 mol% or less, and, as for the modification amount in PVA, it is more preferable that it is 5 mol% or less.

As said vinyl ester used for manufacture of PVA, a vinyl formate, a vinyl acetate, a vinyl propionate, a vinyl butyrate, a vinyl valerate, a vinyl pivalate, a vinyl laurate, a vinyl stearate, a vinyl benzoate, a versacet, Vinyl acid etc. are mentioned. These vinyl esters can be used individually or in combination. Among these vinyl esters, vinyl acetate is preferable from the viewpoint of productivity.

Moreover, as said comonomer, For example, C2-C30 olefins (alpha-olefin etc.), such as ethylene, propylene, 1-butene, isobutene; Acrylic acid or a salt thereof; Acrylic esters such as methyl acrylate, ethyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, i-butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, and octadecyl acrylate ( For example, C1-C18 alkyl ester of acrylic acid, etc.); Methacrylic acid or salts thereof; Methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, 2-methacrylate Methacrylic acid esters such as ethylhexyl, dodecyl methacrylate and octadecyl methacrylate (for example, C1-C18 alkyl ester of methacrylic acid); Acrylamide; N-methyl acrylamide, N-ethyl acrylamide, N, N-dimethyl acrylamide, diacetone acrylamide, acrylamide propanesulfonic acid or its salt, acrylamide propyl dimethylamine or its salt, N-methylol acrylamide or its Acrylamide derivatives such as derivatives; Methacrylamide; Methacrylamide derivatives such as N-methyl methacrylamide, N-ethyl methacrylamide, methacrylamide propanesulfonic acid or salts thereof, methacrylamidepropyldimethylamine or salts thereof, N-methylol methacrylamide or derivatives thereof; N-vinylamides, such as N-vinylformamide, N-vinylacetamide, and N-vinylpyrrolidone; Vinyl such as methyl vinyl ether, ethyl vinyl 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 Ethers; Nitriles such as acrylonitrile and methacrylonitrile; Vinyl halides such as vinyl chloride, vinylidene chloride, vinyl fluoride and vinylidene fluoride; Allyl compounds such as allyl acetate and allyl chloride; Derivatives such as unsaturated dicarboxylic acids such as maleic acid and itaconic acid, salts thereof or esters thereof; Vinyl silyl compounds such as vinyl trimethoxysilane; Isopropenyl acetate; Unsaturated sulfonic acid or derivatives thereof; and the like. These comonomers may be used individually by 1 type, or may use 2 or more types together. Among these comonomers, α-olefins are preferable, and ethylene is particularly preferable.

It is preferable that it is 1,000 or more from a viewpoint of the polarization performance, durability, etc. of the polarizing film obtained, as for the polymerization degree of PVA, It is more preferable that it is 1,500 or more, It is more preferable that it is 2,000 or more. Moreover, it is preferable that the polymerization degree of PVA is 8,000 or less, and, as for a polymerization degree of PVA from a viewpoint of the ease of manufacture, stretchability, etc. to make a homogeneous PVA film, it is more preferable that it is 6,000 or less. The polymerization degree of PVA in this specification means the average degree of polymerization measured according to description of JISK6726-1994, and is calculated | required from the intrinsic viscosity measured in 30 degreeC water after re-soaping and refine | purifying PVA.

It is preferable that it is 95 mol% or more from a viewpoint of the polarization performance, durability, etc. of the polarizing film obtained, as for the saponification degree of PVA, it is more preferable that it is 98 mol% or more, and it is still more preferable that it is 99 mol% or more. The saponification degree of PVA in the present specification is the ratio of the mole number of the vinyl alcohol unit to the total mole number of the structural unit (typically a vinyl ester unit) and the vinyl alcohol unit that can be converted to vinyl alcohol units by saponification ( Mol%). The saponification degree of PVA can be measured according to description of JISK6726-1994.

1 type of PVA may be sufficient as PVA which comprises a PVA film, and 2 or more types of PVA in which 1 or 2 or more differ from polymerization degree, saponification degree, modification degree, etc. may be sufficient. It is preferable that the content rate of PVA in a PVA film exists in the range of 50-100 mass%, It is more preferable to exist in the range of 80-100 mass%, It is still more preferable to exist in the range of 85-100 mass%.

PVA film contains a plasticizer in that mechanical properties such as impact strength can be improved, process passability and stretchability during secondary processing can be improved, and the roll of the present invention can be obtained more efficiently. It is preferable. Preferred plasticizers include polyhydric alcohols, and specific examples thereof include ethylene glycol, glycerin, diglycerin, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol and trimethylolpropane. A PVA film can contain 1 type, or 2 or more types of these plasticizers. Among these plasticizers, one or two or more of glycerin, diglycerine, and ethylene glycol are preferably used, and glycerin is more preferably used from the viewpoint of the effect of improving the stretchability when the PVA film is stretched and used.

It is preferable that the content rate of the plasticizer in a PVA film exists in the range of 1-30 mass%. When the content rate of the plasticizer in a PVA film is less than 1 mass%, since the flexibility of a film is inadequate, it will be easy to produce the problem which a film cracks at the time of winding and inferior the elongation at the time of polarizing plate manufacture. It is more preferable that it is 5 mass% or more from such a viewpoint, and it is still more preferable that it is 10 mass% or more. Moreover, when the content rate of the plasticizer in a PVA film exceeds 30 mass%, bleed out will generate | occur | produce during storage of a roll, the nonuniformity of a physical property will arise in the surface of a PVA film, and uniformity will be inhibited, or a film may be stuck. It is easy to cause problems. From such a viewpoint, it is more preferable that the said content rate is 20 mass% or less, and it is still more preferable that it is 15 mass% or less.

It is preferable that a PVA film contains surfactant from a viewpoint of the handleability, the peelability from the film forming apparatus at the time of manufacturing a PVA film, etc. There is no restriction | limiting in particular in the kind of surfactant, Anionic surfactant, Nonionic surfactant, etc. are mentioned.

As an anionic surfactant, Carboxylic acid types, such as potassium laurate; Sulfate ester types such as octyl sulfate; Sulfonic acid types such as dodecylbenzenesulfonate, and the like.

As nonionic surfactant, For example, Alkyl ether type, such as polyoxyethylene lauryl ether and polyoxyethylene oleyl ether; Alkyl phenyl ether types, such as polyoxyethylene octyl phenyl ether; Alkyl ester types such as polyoxyethylene laurate; Alkyl amine types, such as polyoxyethylene lauryl amino ether; Alkyl amide type, such as polyoxyethylene lauric acid amide; Polypropylene glycol ether types such as polyoxyethylene polyoxypropylene ether; Alkanolamide types such as lauric acid ethanolamide and oleic acid ethanolamide; And allyl phenyl ether types such as polyoxyalkylene allyl phenyl ether.

PVA film can contain 1 type (s) or 2 or more types of these surfactant. Among these surfactants, nonionic surfactants are preferred from the viewpoint of excellent effect of reducing the film surface abnormality at the time of film forming, and particularly preferred are alkanolamide type surfactants, and aliphatic carboxylic acids (eg, having 8 carbon atoms). More preferred is a dialkananamide (for example, diethanolamide, etc.) of saturated or unsaturated aliphatic carboxylic acid of from 30 to 30;

In this invention, it is preferable that the content rate of surfactant in a PVA film exists in the range of 0.01-1 mass%. When the content rate of surfactant is too small, the handleability of PVA film, the peelability from the film forming apparatus at the time of manufacturing a PVA film may worsen, or blocking may arise. From this viewpoint, it is more preferable that it is 0.02 mass% or more, and, as for the content rate of surfactant, it is still more preferable that it is 0.05 mass% or more. On the other hand, when the content rate of surfactant is too high, it will bleed out and it will be easy to produce the problem that an optical nonuniformity arises in the polarizing plate obtained or the transparency of a film deteriorates. From this viewpoint, it is more preferable that it is 0.5 mass% or less, and, as for the content rate of surfactant, it is still more preferable that it is 0.3 mass% or less.

The PVA film may further contain other components, such as an antioxidant, a ultraviolet absorber, a lubricating agent, a coloring agent, a preservative, a preservative, a high molecular compound other than the above-mentioned component, and water, as needed. A PVA film can contain 1 type, or 2 or more types of these other components.

The manufacturing method of a PVA film is not specifically limited, The manufacturing method by which the thickness and width of a film after film forming become more uniform can be employ | adopted preferably, For example, the above-mentioned PVA which comprises a PVA film, and a plasticizer further as needed. 1 type or 2 types or more of surfactant, and the said film forming stock solution which melt | dissolved in the liquid medium, PVA, and also a plasticizer, surfactant, the said other component, and the said liquid medium, 1 or 2 or more types as needed. It can contain and can manufacture using the film forming undiluted | stock solution which PVA melt | dissolves. When the said film forming undiluted | stock solution contains at least 1 sort (s) of a plasticizer, surfactant, and the said other component, it is preferable that the components are mixed uniformly.

As said liquid medium used for preparation of a film forming undiluted | stock solution, For example, water, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, ethylene glycol, glycerin, propylene glycol, diethylene glycol, Triethylene glycol, tetraethylene glycol, trimethylol propane, ethylenediamine, diethylenetriamine, etc. are mentioned, One or two or more of these can be used. Among these, water and dimethyl sulfoxide are preferable and water is more preferable.

The volatilization fraction of the undiluted film forming solution (content ratio in the undiluted stock solution of volatile components such as a liquid medium removed by volatilization or evaporation at the time of film forming) also varies depending on the degree of polymerization of PVA, the film forming method, the film forming conditions, and the like. It is preferable that it is% or more, It is more preferable that it is 25 mass% or more, It is more preferable that it is 30 mass% or more, It is especially preferable that it is 40 mass% or more, It is preferable that it is 95 mass% or less, It is more preferable that it is 90 mass% or less It is more preferable that it is 85 mass% or less, and it is especially preferable that it is 70 mass% or less. When the volatilization fraction of a film forming undiluted | stock solution is more than the said minimum, the viscosity of a film forming undiluted | stock solution does not become high too much, filtration and defoaming at the time of preparation of a undiluted film undiluted | stock solution are performed smoothly, and manufacture of a PVA film with few foreign substances and a fault becomes easy. On the other hand, when the volatilization fraction of a film forming undiluted | stock solution is below the said upper limit, the density | concentration of a film forming undiluted | stock solution does not become low too much, and manufacture of industrial PVA film becomes easy.

As a film forming method at the time of forming a PVA film using said film forming undiluted | stock solution, the cast film forming method, the extrusion film forming method, the wet film forming method, the gel film forming method, etc. are mentioned, for example. Only 1 type may be employ | adopted for these film forming methods, and may be employ | adopted in combination of 2 or more type. Among these film forming methods, the cast film forming method and the extrusion film forming method are preferable from the viewpoint of obtaining a good PVA film.

As an example of the specific manufacturing method of a PVA film, the said film forming undiluted | stock solution is the most upstream side using the well-known film discharge apparatus (film casting apparatus), such as a T-type slit die, a hopper plate, an I-die, a lip coater die, for example. Volatile components from one side of the film uniformly discharged or pliable on the peripheral surface of the rotating heated first roll (or belt) located at and positioned on the peripheral surface of the first roll (or belt) Industrially preferably employ a method of evaporating to dry, drying further on the peripheral surface of one or more rotating heated rolls arranged downstream thereof, or passing through a hot air drying apparatus. Can be. You may perform drying by a heated roll and the drying by a hot air drying apparatus in combination suitably.

The thickness of the PVA film in the roll of this invention needs to be 45 micrometers or less. When the thickness of a PVA film is 45 micrometers or less, a thin polarizing film can be manufactured efficiently. And a thin polarizing plate can be manufactured efficiently by using such a thin polarizing film. Conventionally, when the PVA film is thin and the winding length is long, fine wrinkles and eccentricity are generated and there is a problem that a roll having a good appearance shape cannot be obtained. In contrast, according to the present invention, even when the PVA film is thin and the winding length is long, wrinkles and eccentricity are hardly generated and a roll of PVA film having a good appearance shape is obtained. Therefore, the effect of this invention is acquired remarkably when the thickness of a PVA film is 45 micrometers or less. From the above point of view, the thickness of the PVA film is preferably 40 µm or less, more preferably 35 µm or less, still more preferably 30 µm or less, particularly preferably 25 µm or less, and most preferably 20 µm or less. On the other hand, when the thickness of a PVA film is too thin, there exists a tendency for the secondary processing of the film processed by optical films, such as a polarizing film, to become difficult. Therefore, it is preferable that the said thickness is 1 micrometer or more, It is more preferable that it is 3 micrometers or more, It is more preferable that it is 5 micrometers or more, It is especially preferable that it is 10 micrometers or more.

The winding length of the PVA film in the roll of this invention, ie, the length of the PVA film wound up, needs to be 2,000 m or more. When the length of a PVA film is 2,000 m or more, even if optical films, such as a polarizing film manufactured, are large area, what is excellent in the uniformity of optical performance can be manufactured continuously with favorable efficiency. Moreover, conventionally, when a PVA film was thin and a winding length was long, there existed a problem that a fine wrinkle and eccentricity generate | occur | produce and the roll with a favorable external shape is not obtained. In contrast, according to the present invention, even when the PVA film is thin and the winding length is long, wrinkles and eccentricity are hardly generated and a roll of PVA film having a good appearance shape is obtained. Therefore, when the length of a PVA film is 2,000 m or more, the effect of this invention is acquired remarkably. In view of the above, the length of the PVA film is preferably 3,000 m or more, more preferably 4,000 m or more, still more preferably 5,000 m or more, particularly preferably 8,000 m or more, and most preferably 12,000 m or more. Although there is no restriction | limiting in particular as an upper limit of the length of a PVA film, It is preferable that the said length is 30,000 m or less, and it is more preferable that it is 22,000 m or less from the point which the roll of a PVA film better than an external shape is easily obtained. The length of a PVA film may be 18,000 m or less, Furthermore, 15,000 m or less.

There is no restriction | limiting in particular in the width of a PVA film, For example, it can be 50 cm or more. By the way, normally, the width | variety of a PVA film tends to produce wrinkles and eccentricity easily in the roll obtained. On the other hand, according to this invention, since generation | occurrence | production of a wrinkle and an eccentricity are reduced even if the width | variety of a PVA film is wide, the effect of this invention is acquired more remarkably in such a case. Moreover, by using a wide PVA film, the wide polarizing film which can respond to the large screen of LCD can be manufactured. In these respects, the width of the PVA film is preferably 2 m or more, more preferably 2.5 m or more, still more preferably 2.7 m or more, particularly preferably 3 m or more, and 3.5 m or more. Although there is no restriction | limiting in particular as an upper limit of the width | variety of a PVA film, From the point which the roll of a PVA film with a favorable external shape is easily obtained, it is preferable that the said width is 6 m or less, It is more preferable that it is 5 m or less, It is more preferable that it is 4.2 m or less desirable. It is preferable that it is 4 m or less, and, as for the point which the PVA film which is especially excellent in external shape is obtained, it is more preferable that it is 3.8 m or less.

In the roll of this invention, the average space | interval between neighboring films (between neighboring PVA films in the radial direction of a roll) needs to be 5 micrometers or less. The said average space | interval corresponds to the thickness of the air layer between films. When the said average space | interval is 5 micrometers or less, even if a PVA film is thin and a winding length is long, wrinkles and an eccentricity do not generate | occur | produce well and the roll with a favorable external shape is obtained. From such a viewpoint, the average interval is preferably 4.9 µm or less, more preferably 4.5 µm or less, still more preferably 4.2 µm or less, further 4 µm or less, or even 3.8 µm or less. Moreover, when the average distance between neighboring films is less than 2 micrometers, blocking will generate | occur | produce, a fluctuation will arise at the time of unwinding of a PVA film, or an abnormality in appearance, such as a wrinkle, may arise in a film by winding a PVA film roll tightly, It is easy to cause the problem that uniformity is impaired. It is preferable that it is 2 micrometers or more from this viewpoint, It is more preferable that it is 2.5 micrometers or more, It is further more preferable that it is 3 micrometers or more, 3.5 micrometers or more are especially preferable.

The average spacing between the neighboring films can be obtained by the following method. That is, the average space | interval N (micrometer) between the said neighboring films in the outer diameter H (m) roll by which the PVA film of length L (m) and thickness M (micrometer) is wound up to the cylindrical core of outer diameter D (m). ) Is the following formula:

N = {(π / 4) (H ² -D ² ) / L} × 10 ⁶ -M

It can calculate by

Although there is no restriction | limiting in particular in the manufacturing method of the roll of this invention, According to the manufacturing method of the following this invention, since the said roll can be manufactured efficiently, it is preferable. That is, the manufacturing method of this invention is a manufacturing method of the roll by which the PVA film whose thickness is 45 micrometers or less and length is 2,000 m or more is wound up,

(a) In the winding-up process of a PVA film, a PVA film is made to contact the outer peripheral surface of the film roll (film state part) formed with the PVA film already wound up, making the contact roll arrange | positioned substantially parallel with respect to the axial direction of the said film roll. Winding up,

(b) the pressure between the film roll and the contact roll is 3 to 30 N per 1 m in the axial direction of the film roll,

(c) It is a manufacturing method whose winding speed is 30 m / min or less.

In the manufacturing method of this invention, what was mentioned above can be used as a PVA film used for manufacture of the roll of this invention as a PVA film used for manufacture of a roll.

In the manufacturing method of this invention, in the winding-up process of a PVA film, a PVA film is made to contact the outer peripheral surface of the film roll formed with the PVA film already wound, making the contact roll arrange | positioned substantially parallel with respect to the axial direction of the said film roll. Adopt a touch winding method to wind up. 1 is a schematic view showing an example of the touch winding method. As shown in FIG. 1, the contact roll 2 arrange | positioned substantially parallel to the axial direction of the said film roll 1 in the outer peripheral surface of the film roll 1 formed of the PVA film 3 wound up already is The roll is manufactured by winding up the PVA film 3 further in direct contact. As the contact roll 2 used, the thing longer than the length of the axial direction of the film roll 1 can be used. In the position 5 at which the PVA film 3 is wound on the film roll 1, the film roll 1 and the contact roll 2 are preferably in contact with each other over the entire axial direction of the film roll 1. Do. In addition, as a method other than the touch winding method, a near winding method shown in FIG. 2 is known. As shown in FIG. 2, in the near winding method, when the PVA film 3 is wound, a space (gap) is formed between the outer circumferential surface of the film roll 1 formed of the PVA film already wound and the contact roll 2. Maintained.

Although there is no restriction | limiting in particular in the length of the contact roll 2, It is preferable that it is long in the range of 3-200 cm than the width of the film roll 1, It is more preferable that it is long in the range of 5-100 cm, 10-10 It is more preferable that it is long in the range of 50 cm.

Although there is no restriction | limiting in particular in the diameter of the contact roll 2, From an viewpoint of strength, handleability, etc., it is preferable that the outer diameter exists in the range of 50-1000 mm, It is more preferable to exist in the range of 75-800 mm, 100- It is more preferable to exist in the range of 500 mm, and it is especially preferable to exist in the range of 125-350 mm. The material of the surface layer of the contact roll 2 is not specifically limited, Rubber, resin, a metal, etc. are mentioned, Especially, rubber is preferable.

In the manufacturing method of this invention, when winding up the PVA film 3, the pressure (pressure which presses the contact roll 2 to the film roll 1) between the film roll 1 and the contact roll 2 is a film roll. It is in the range of 3-30 N per 1 m of length of the axial direction of (1). Hereinafter, the said pressure may be called "winding contact pressure", and "N / m" may be used as a unit for showing that it is the pressure per length 1m of the axial direction of a film roll. By carrying out a winding contact pressure in the said range, the roll of this invention can be manufactured efficiently. From this viewpoint, it is preferable that the said winding contact pressure is 20 N / m or less, It is more preferable that it is 10 N / m or less, It is further more preferable that it is 8 N / m or less. It is preferable that it is 3.5 N / m or more from a viewpoint which can manufacture the roll of this invention with more favorable efficiency, and it is more preferable that it is 4 N / m or more.

In the manufacturing method of this invention, the winding speed at the time of winding up the PVA film 3 is made into 30 m / min or less. The roll of this invention can be manufactured efficiently by making a winding speed into 30 m / min or less. It is preferable that this winding speed is 25 m / min or less from this viewpoint. From the viewpoint of producing the roll of the present invention more efficiently, the winding speed is preferably 9 m / min or more, and more preferably 15 m / min or more.

In the manufacturing method of this invention, the film | membrane formed by the PVA film already wound up the winding tension (tension which is applied to the longitudinal direction of the PVA film 3 when winding up a PVA film) when winding up a PVA film 3 It is preferable to set it as 80 N or less per 1 m of lengths in the axial direction of the roll 1. Hereinafter, "N / m" may be used as a unit for showing that it is the winding tension per 1 m of lengths in the axial direction of the film roll 1. By carrying out a winding tension in the said range, the roll of this invention can be manufactured more efficiently. From this viewpoint, it is more preferable that it is 75 N / m or less, and it is still more preferable that it is 70 N / m or less. From the viewpoint of producing the roll of the present invention more efficiently, the winding tension is preferably 20 N / m or more, more preferably 40 N / m or more, still more preferably 45 N / m or more, 50 N It is especially preferable that it is / m or more.

FIG. 3 shows the film roll 1 viewed from the direction 11 of the tangential line 10 of the contact roll 2 in the position where the contact roll 2 is in contact with the film roll 1 in FIG. 1. It is an example of schematic diagram of the contact roll 2. In the manufacturing method of this invention, the parallelism (A) of the axis | shaft of the film roll 1 and the axis | shaft of the contact roll 2 calculated | required from the distance of the axis | shaft of the film roll 1 and the axis | shaft of the contact roll 2 is 0.7 mm. It is preferable that it is the following. Thereby, in the position 5 in which the PVA film 3 is wound by the film roll 1, the film roll 1 and the contact roll 2 are easy to contact over the whole axial direction of the film roll 1 Since it loses, the roll of this invention with a favorable external shape can be manufactured more efficiently. It is more preferable that it is 0.5 mm or less, and, as for the parallelism (A), it is still more preferable that it is 0.2 mm or less. In the present invention, the parallelism (A) is a distance (b-a) from one end (b) of the shaft (7) of the contact roll (2) to the axis (6) of the film roll (1) and the contact roll ( The difference of the distance (b'-a ') from the other end b' of the axis | shaft 7 of 2) to the axis | shaft 6 of the film roll 1 is shown. One end b of the shaft 7 of the contact roll 2 is positioned closest to the end 8 of the PVA film 3, and the other end b 'is from the end 9 of the PVA film 3. It is the closest position. Distance (b-a) and distance (b '-a') can be measured using a dial gauge.

FIG. 4 is an example of a schematic view of the film roll 1 and the contact roll 2 viewed in the horizontal direction 12 in FIG. 1. In the manufacturing method of this invention, the film in the case of looking at the film roll 1 and the contact roll 2 in the horizontal direction calculated | required from the horizontality of the axis of the film roll 1, and the horizontality of the axis of the contact roll 2. It is preferable that the parallelism (B) of the axis | shaft of the roll 1 and the axis | shaft of the contact roll 2 is 0.2 mm or less. Thereby, in the position 5 in which the PVA film 3 is wound by the film roll 1, the film roll 1 and the contact roll 2 are easy to contact over the whole axial direction of the film roll 1 Since it loses, the roll of this invention with a favorable external shape can be manufactured more efficiently. It is more preferable that it is 0.15 mm or less, and, as for the parallelism (B), it is still more preferable that it is 0.1 mm or less. The parallelism (B) in the present invention will be specifically described below. The axis 7 of the contact roll 2 is projected on a plane which comprises the axis 6 of the film roll 1 and which is perpendicular to the horizontal plane. And the distance d-c from the one end d of the axis | shaft 7 of the contact roll 2 to the axis | shaft 6 of the film roll 1 in the projection surface, and the axis | shaft of the contact roll 2 The difference of the distance d'-c 'from the other end d' of (7) to the axis | shaft 6 of the film roll 1 is made into the parallelism B. One end d of the shaft 7 of the contact roll 2 is positioned closest to the end 8 of the PVA film 3, and the other end d 'is from the end 9 of the PVA film 3. It is the nearest position. Parallelism (B) can be calculated | required by measuring the horizontal degree of the axial direction of the film roll 1 and the contact roll 2 using a leveler, respectively.

In the roll obtained in this way, it is preferable that the average space | interval between neighboring films is 5 micrometers or less. When the said average space | interval is 5 micrometers or less, even if a PVA film is thin and a winding length is long, wrinkles and an eccentricity do not generate | occur | produce well and the roll with a favorable external shape is obtained. According to the manufacturing method of this invention, it is possible to easily control the said average space | interval. It is preferable that the said average space | interval is 4.9 micrometers or less, It is more preferable that it is 4.5 micrometers or less, It is further more preferable that it is 4.2 micrometers or less, 4 micrometers or less, Furthermore, 3.8 micrometers or less may be sufficient. On the other hand, it is preferable that the said average space | interval is 2 micrometers or more, It is more preferable that it is 2.5 micrometers or more, It is further more preferable that it is 3 micrometers or more, 3.5 micrometers or more are especially preferable.

There is no restriction | limiting in particular in the use of the PVA film in the roll of this invention, For example, a film for pharmaceutical packaging, a base film for hydraulic transfer, a base film for embroidery, a release film for artificial marble molding, a film for seed packaging, a waste accommodation bag It can be used for the use of various water-soluble films, such as a film for use. According to the present invention, even when the PVA film is thin and the winding length is long, wrinkles and eccentricity are hardly generated, and a roll having a good appearance shape is provided. When such a roll is used, the optical film excellent in the uniformity of optical performance can be manufactured continuously with favorable efficiency, even if it is large area. Therefore, it is preferable to use the said PVA film as a raw film for manufacturing an optical film. As such an optical film, a polarizing film, retardation film, etc. are mentioned, for example, A polarizing film is preferable. Such an optical film can be manufactured by performing processes, such as uniaxial stretching, using the said PVA film, for example.

The method at the time of manufacturing a polarizing film using a PVA film is not restrict | limited, You may employ | adopt any method conventionally known. As such a method, for example, dyeing and uniaxial stretching are performed using the PVA film unwound from the roll of this invention, or uniaxial stretching with respect to the PVA film containing the dye unwound from the roll of this invention. Or a method of carrying out this procedure. As a more specific method for manufacturing a polarizing film, swelling, dyeing, uniaxial stretching, and further crosslinking treatment, fixing treatment, drying, heat treatment, etc. are performed on the PVA film unwound from the roll of the present invention. How to do this. In this case, the order of each treatment such as swelling, dyeing, crosslinking treatment, uniaxial stretching, fixing treatment, etc. is not particularly limited, and one or two or more treatments may be performed at the same time. In addition, one or two or more of each processing may be performed two or more times.

The produced polarizing film is usually optically transparent on one or both surfaces thereof, and a protective film having mechanical strength is bonded together and used in the form of a polarizing plate. As the protective film, a cellulose triacetate (TAC) film, a cycloolefin polymer (COP) film, an acetic acid butyric acid cellulose (CAB) film, an acrylic film, a polyester film, or the like is used. Moreover, as an adhesive agent for adhesion | attachment, a PVA-type adhesive agent, a urethane type adhesive agent, etc. are mentioned, Especially, a PVA-type adhesive agent is preferable.

The polarizing plate obtained as mentioned above can be used as an LCD component, after bonding an adhesive, such as an acryl type, to a glass substrate. At the same time, you may bond together a retardation film, a viewing angle improvement film, a brightness improving film, etc.

EXAMPLE

Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited at all by these Examples.

[Evaluation of Appearance Shape]

The outer shape of the roll was evaluated based on the following criteria.

A: No appearance of wrinkles or eccentricity and the appearance is good.

B: Very few wrinkles are confirmed, but no eccentricity is generated and the appearance is good.

C: Fine wrinkles or eccentricity have occurred and appearance is bad.

[Evaluation of Optical Nonuniformity]

The sample film of 15 cm x 5 cm was extract | collected from the center part and both ends of the film roll obtained by the following example and the comparative example. About the said PVA film, the polarizing film was manufactured by performing a swelling process, a dyeing process, a bridge | crosslinking process, an extending process, the fixing process, and a drying process. Four sample films were attached to the stretching jig. While immersing in water of temperature 30 degreeC for 1 minute, it uniaxially stretched (stage 1st stage) in the longitudinal direction MD at 2.2 times the original length. Then, uniaxially stretched in the longitudinal direction (MD) to 3.2 times the original length while immersing for 2 minutes in a dye bath at a temperature of 30 ° C. containing iodine at a concentration of 0.03% by mass and potassium iodide at a concentration of 3.0% by mass ( 2nd stage extension). Subsequently, uniaxially stretching in the longitudinal direction (MD) to 3.6 times the original length while immersing in a crosslinking bath at a temperature of 30 ° C. containing 3.0 mass% of boric acid and 3.0% by weight of potassium iodide at a concentration of 2% (3rd stage stretching). ). Further, uniaxial stretching (fourth stage stretching) was performed while immersing in a stretching bath at a temperature of 55 ° C. containing boric acid at a concentration of 4.0% by mass and potassium iodide at a concentration of 5.0% by mass, and at the time when two of the four films were cut. Two uncut sheets were removed from the stretch bath. Thereafter, the film was washed by immersion for 5 seconds in a fixed treatment bath at a temperature of 22 ° C. containing 1.5% by mass of boric acid and 5% by mass of potassium iodide, followed by drying for 240 seconds with a 60 ° C. dryer. A polarizing film was prepared.

The sample film of 5 cm x 5 cm was sampled from the center part of the obtained polarizing film, and it installed so that it might become a cross nicol state on one polarizing plate (43.5% of single transmittances, 99.9% of polarization degree). Using a backlight with a brightness of 15000 candela, the difference in contrast resulting from the nonuniformity (optical nonuniformity) of the transmittance between the film taken from the center portion of the film roll and the film taken from the end portion was observed, and the optical nonuniformity was evaluated based on the following criteria. .

A: The difference in contrast between the film taken from the center and the film taken from both ends is not seen and is uniform.

B: There is a slight difference in contrast due to the difference in transmittance between the film taken from the center and the film taken from both ends.

C: There is a clear contrast between the film taken from the center and the film taken from both ends.

Example 1

PVA film composed of PVA having a degree of polymerization of 2,400, saponification degree of 99 mol% or more (thickness 30 µm, length 20,000 m, width 4.2 m, 10 mass% of glycerin as a plasticizer, and 0.1 mass% of lauric acid ethanolamide as a surfactant) Containing) into a cylindrical core to produce a roll. Moreover, as a winding system, the contact roll (outer diameter: 210 mm, roll length: 4950 mm) arrange | positioned substantially parallel to the axial direction of the said film roll is made to contact the outer peripheral surface of the film roll formed from the PVA film already wound up. The touch winding system which winds up a PVA film was employ | adopted. Specific conditions are shown in Table 1.

The average space | interval between neighboring films in the obtained roll was 4.15 micrometers. The external shape of the roll was evaluated by the above method. Moreover, the manufacturing and polarization evaluation of the polarizing film were performed by the said method. The above results are shown in Table 1.

Examples 2-8, Comparative Examples 2-5

Production and evaluation of the rolls were carried out in the same manner as in Example 1 except that the thickness, length, width, plasticizer content and surfactant content of the PVA film used for the roll, and the manufacturing conditions of the roll were changed as shown in Table 1. It was. The results are shown in Table 1.

Comparative Example 1

PVA film composed of PVA having a degree of polymerization of 2,400, saponification degree of 99 mol% or more (thickness 30 μm, length 20,000 m, width 3.3 m, glycerin as a plasticizer, 10 mass%, and surfactant 0.1% by weight of lauric acid ethanolamide) Containing) into a cylindrical core to produce a roll. Moreover, the near winding system was employ | adopted as a winding system. Specific conditions are shown below.

[Contact roll]

Shaft Diameter: 210 mm

Roll Length: 4950 mm

[Coiling condition]

Winding pressure: None (near winding method)

Winding Speed: 24 m / min

Winding tension: 100 N / m

Parallelism A: 0.8 mm

Parallelism B: 0.2 mm

The obtained roll was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Reference Example 1

PVA film composed of PVA having a degree of polymerization of 2,400 and a saponification degree of 99 mol% or more (thickness 60 μm, length 9,600 m, width 4.2 m, 10 mass% of glycerin as a plasticizer, and 0.1 mass% of lauric acid ethanolamide as a surfactant) Containing) into a cylindrical core to produce a roll. Moreover, the near winding system was employ | adopted as a winding system. Specific conditions are shown below.

[Contact roll]

Shaft Diameter: 210 mm

Roll Length: 4950 mm

[Coiling condition]

Winding pressure: None (near winding method)

Winding Speed: 12 m / min

Winding Tension: 52 N / m

Parallelism A: 0.8 mm

Parallelism B: 0.2 mm

The obtained roll was evaluated in the same manner as in Example 1. The results are shown in Table 1.

1: film roll
2: contact roll
3: PVA film
4: cylindrical core
5: position where the PVA film is wound
6: axis of film roll
7: axis of contact roll
8, 9: end of PVA film
10: tangent
11, 12: direction

Claims (10)

A roll in which a polyvinyl alcohol film having a thickness of 45 µm or less and a length of 2,000 m or more is wound, wherein an average interval between neighboring films is 2 µm or more and 5 µm or less. The method of claim 1,
The roll whose content rate of the plasticizer in a polyvinyl alcohol film is 1-30 mass%. The method of claim 1,
The roll which is 0.01-1.0 mass% of content rate of surfactant in a polyvinyl alcohol film. The method of claim 1,
The roll whose polyvinyl alcohol film has a width of 2 m or more. The method of claim 1,
The roll in which a polyvinyl alcohol film is a raw film for optical film manufacture. The method of claim 5,
The roll in which an optical film is a polarizing film. As a manufacturing method of the roll of any one of Claims 1-6,
(a) In the winding-up process of a polyvinyl alcohol film, the polyvinyl alcohol film is made to contact the outer peripheral surface of the film roll formed with the polyvinyl alcohol film wound up already, making contact roll arrange | positioned parallel to the axial direction of the said film roll. Winding up,
(b) the pressure between the film roll and the contact roll is 3 to 30 N per 1 m in the axial direction of the film roll,
(c) The manufacturing method of the roll whose winding speed is 30 m / min or less. The method of claim 7, wherein
The manufacturing method of the roll whose winding tension is 80 N or less per 1 m of lengths in the axial direction of a film roll. The method of claim 7, wherein
The parallelism A of the axis | shaft of a film roll and the axis | shaft of a contact roll calculated | required from the distance of the axis | shaft of a film roll and the axis of a contact roll is a manufacturing method of the roll. The method of claim 7, wherein
The parallelism B of the film roll axis | shaft and the contact roll axis | shaft at the time of looking at the film roll and a contact roll in the horizontal direction calculated | required from the horizontality of the axis of a film roll and the axis of a contact roll is 0.2 mm or less.

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