KR102375984B1 - Polyvinyl alcohol film roll - Google Patents

Abstract

A roll formed by winding a PVA film having a thickness of 45 µm or less and a length of 2,000 m or more, wherein the average spacing between adjacent films is 5 µm or less; And, as a method of manufacturing 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, a touch winding method is employed, and the pressure between the film roll and the contact roll is 1 m in the axial direction of the film roll. Sugar is 3 to 30 N, and the winding speed is set to a manufacturing method of 30 m/min or less. Thereby, even if it is a case where a PVA film is thin and winding length is long, wrinkles and eccentricity do not generate|occur|produce easily, and the roll of a PVA film with a favorable external appearance 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 external shape, and a method 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 liquid crystal monitor, is generally dyed with a polyvinyl alcohol film (hereinafter, “polyvinyl alcohol” may be abbreviated as “PVA”), 1 By bonding protective films, such as a cellulose triacetate (TAC) film, to the surface of the obtained polarizing film after performing axial stretching and the fixing process by a boron compound etc. further as needed and manufacturing a polarizing film is manufactured

In recent years, LCDs are being made larger or thinner. As a means for achieving thinning of LCD, the method of thinning the glass used for it can be considered. When thinning glass, it is necessary to also thin a polarizing plate and to reduce the shrinkage stress of the said polarizing plate. Therefore, it is calculated|required to manufacture a thin-shaped polarizing film using a thinner PVA film (for example, refer patent document 1 etc.).

A PVA film is usually stored or transported in the form of a roll in which a long PVA film was wound around a cylindrical core (for example, refer patent document 2 etc.). A roll of a PVA film having a wider width, a longer winding length, and higher quality is required in order to continuously produce a polarizing plate with a large area having excellent uniformity in optical performance with good efficiency. Patent Document 2 discloses a method of winding a PVA film on the cylindrical core by passing a PVA film between the guide roll and the core pipe additionally formed on the cylindrical core, wherein the guide roll and the cylindrical core are spaced apart from each other. A method of winding in an installed non-contact state or in a state in which the guide roll and the cylindrical core tube are in contact with the PVA film interposed therebetween is described. However, when the PVA film was thinner and the winding length was long, fine wrinkles or eccentricity in which the center of gravity of the roll was shifted occurred, and a roll having a good external appearance was not obtained. When such a roll of a PVA film was used as a raw material, fluctuation|variation generate|occur|produced at the time of unwinding of a PVA film, the uniformity of the said PVA film was inhibited, and it had become a problem.

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

The present invention has been made in order to solve the above problems, and an object of the present invention is to provide a roll of a PVA film having a thin PVA film and a long winding length, which does not easily generate wrinkles or eccentricity, and has a good appearance shape.

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

That is, the present invention is

[1] A roll formed by winding a PVA film having a thickness of 45 µm or less and a length of 2,000 m or more, wherein the average spacing between adjacent films is 5 µm or less;

[2] The roll according to the above [1], wherein the 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 mass%;

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

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

[6] The roll as described in any one of said [1]-[5] whose PVA film is a raw film for optical film manufacture;

[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 μm or less and a length of 2,000 m or more is wound,

(a) In the winding process of the polyvinyl alcohol film, the outer peripheral surface of the film roll formed of the already wound polyvinyl alcohol film is brought into contact with a contact roll arranged substantially parallel to the axial direction of the film roll, while contacting the polyvinyl alcohol film wind 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) a manufacturing method whose winding speed is 30 m/min or less;

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

[10] The manufacturing 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 from 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 is viewed in the horizontal direction, obtained from the horizontality of the axis of the film roll and the horizontality of the axis of the contact roll, is 0.2 mm or less, the [ 8] - the manufacturing method in any one of [10];

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

is about

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

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

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail. In the roll of the present invention, a PVA film having a thickness of 45 µm or less and a length of 2,000 m or more is wound. And in the roll of this invention, the average space|interval between adjacent 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 on a cylindrical core from viewpoints, such as the quality of the roll obtained, handleability, etc. There is no restriction|limiting in particular in the kind of cylindrical core, For example, a metal thing, a plastic thing, a paper thing, a wooden thing, etc. are mentioned. In addition, composite cores such as those in which both metal and plastic are used, those in which both metal and paper are used, and those in which both plastics and paper are used can also be used. Among these, strength is high, and while the effect of this invention is acquired more remarkably, in manufacture of optical films, such as a polarizing film, there is also little dusting which tends to become a problem, etc. from a metal and/or plastic A core of is preferable, and a metal core is more preferable at the point that it is not easily affected by abrasion etc. even if it uses repeatedly. The ratio of the mass of metal and plastic to the total mass of the cylindrical core is preferably 50 mass% or more, more preferably 80 mass% or more, still more preferably 95 mass% or more, and 100 mass% Especially preferred.

As said metal, iron, stainless steel, aluminum etc. are mentioned, for example, Among these, 1 type may be used independently and 2 or more types may be used together. Among these, from the viewpoints of strength, lightness, price, and the like, aluminum and iron are preferable.

In addition, as the plastic, for example, polyvinyl chloride, polyvinylidene chloride, polyester, polycarbonate, polyamide, epoxy resin, polyurethane, polyurea, silicone resin, etc. are mentioned, one of them 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 plastics are fiber reinforced plastics (FRP), such as a carbon fiber reinforced plastics, from viewpoints, such as intensity|strength.

There is no particular limitation on the length of the cylindrical core, but from the viewpoint of handleability, etc., it is preferable that it is longer than the width of the PVA film to be wound within the range of 5 to 100 cm, and the length within the range of 10 to 45 cm is more It is preferable, and it is more preferable that it is long within the range of 15-30 cm.

Although there is no restriction|limiting in particular in the diameter of the cylindrical core, It is preferable that it exists in the range of 50-800 mm, and it is more preferable that it exists in the range of 80-500 mm, from a viewpoint of strength, handleability, etc., 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. Further, 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, and furthermore in the range of 4 to 10 mm from the viewpoints of strength and handleability. desirable.

As PVA constituting the PVA film used in the present invention, for example, unmodified PVA obtained by saponifying polyvinyl ester obtained by polymerizing vinyl ester, modified PVA obtained by graft copolymerizing a comonomer to the main chain of PVA, vinyl Modified PVA obtained by saponifying a modified polyvinyl ester obtained by copolymerizing an ester and a comonomer, or a so-called polyvinyl acetal resin in which a part of the hydroxyl groups of unmodified PVA or modified PVA are crosslinked with aldehydes such as formalin, butyraldehyde, benzaldehyde, etc. can When PVA which comprises a PVA film is modified PVA, it is preferable that it is 15 mol% or less, and, as for the modified amount in PVA, it is more preferable that it is 5 mol% or less.

Examples of the vinyl ester used in the production of PVA include vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl valerate, vinyl pivalate, vinyl laurate, vinyl stearate, vinyl benzoate, versat. vinyl acid; and the like. 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, and isobutene; Acrylic acid or its salt; Acrylic acid 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 alkylester of acrylic acid, etc.); methacrylic acid or its salt; Methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, 2- methacrylic acid methacrylic acid esters such as ethylhexyl, dodecyl methacrylate, and octadecyl methacrylate (eg, alkyl esters having 1 to 18 carbon atoms of methacrylic acid, etc.); acrylamide; N-methylacrylamide, N-ethylacrylamide, N,N-dimethylacrylamide, diacetoneacrylamide, acrylamidepropanesulfonic acid or a salt thereof, acrylamidepropyldimethylamine or a salt thereof, N-methylolacrylamide or its salt acrylamide derivatives such as derivatives; methacrylamide; methacrylamide derivatives such as N-methylmethacrylamide, N-ethylmethacrylamide, methacrylamidepropanesulfonic acid or a salt thereof, methacrylamidepropyldimethylamine or a salt thereof, N-methylolmethacrylamide or a derivative thereof; N-vinylamides, such as N-vinylformamide, N-vinylacetamide, and N-vinylpyrrolidone; Vinyls 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, and 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, its salt, or its ester; vinylsilyl compounds such as vinyl trimethoxysilane; isopropenyl acetate; Unsaturated sulfonic acid or its derivative(s), etc. are mentioned. Either of these comonomers may be used individually by 1 type, or may use 2 or more types together. Among these comonomers, ?-olefin is preferable, and ethylene is particularly preferable.

From viewpoints, such as the polarization performance and durability of the polarizing film obtained, it is preferable that it is 1,000 or more, It is more preferable that it is 1,500 or more, It is more preferable that the polymerization degree of PVA is 2,000 or more. Moreover, it is preferable that it is 8,000 or less, and, as for the polymerization degree of PVA from viewpoints of the ease of manufacture for setting it as a homogeneous PVA film, ductility, etc., 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 after resaponifying and refine|purifying PVA, it calculates|requires from the intrinsic viscosity measured in 30 degreeC water.

It is preferable that it is 95 mol% or more from viewpoints, such as polarization performance and durability of the polarizing film obtained, as for the saponification degree of PVA, it is more preferable that it is 98 mol% or more, It is still more preferable that it is 99 mol% or more. The degree of saponification of PVA in the present specification refers to the ratio of the number of moles of the vinyl alcohol unit to the total number of moles of a structural unit (typically a vinyl ester unit) that can be converted to a vinyl alcohol unit by saponification and a vinyl alcohol unit ( 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 from which 1 or 2 or more differ among a polymerization degree, a saponification degree, a denaturation degree, etc. may be sufficient as it. It is preferable to exist in the range of 50-100 mass %, as for the content rate of PVA in a PVA film, it is more preferable to exist in the range of 80-100 mass %, It is more preferable to exist in the range of 85-100 mass %.

Mechanical properties such as impact strength can be improved, process passability and stretchability can also be improved during secondary processing, and the roll of the present invention can be obtained more efficiently, etc., so that the PVA film contains a plasticizer. it is preferable A polyhydric alcohol is mentioned as a preferable plasticizer, ethylene glycol, glycerol, diglycerol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, trimethylol propane, etc. are mentioned specifically,. A PVA film can contain the 1 type(s) or 2 or more types of these plasticizers. Among these plasticizers, one or two or more of glycerin, diglycerin, and ethylene glycol are preferably used, and glycerin is more preferably used from the viewpoints of the effect of improving stretchability when stretching and using a PVA film.

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 softness|flexibility of a film is insufficient, it is easy to raise the problem that a film cracks at the time of winding-up, or the stretchability at the time of polarizing plate manufacture is inferior. From such a viewpoint, it is more preferable that the said content rate is 5 mass % or more, 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 occurs during storage of a roll, and physical property nonuniformity arises in the surface of a PVA film, uniformity is inhibited, or agglutination of a film prone to causing 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 viewpoints, such as the improvement of the handleability and the peelability from the film forming apparatus at the time of manufacturing a PVA film. There is no restriction|limiting in particular in the kind of surfactant, Anionic surfactant, nonionic surfactant, etc. are mentioned.

As anionic surfactant, Carboxylic acid types, such as potassium laurate; Sulfuric acid ester types, such as octyl sulfate; Sulfonic acid types, such as dodecylbenzenesulfonate, etc. are mentioned.

As a nonionic surfactant, For example, alkyl ether types, such as polyoxyethylene lauryl ether and polyoxyethylene oleyl ether; Alkylphenyl ether types, such as polyoxyethylene octylphenyl ether; Alkyl ester types, such as polyoxyethylene laurate; Alkylamine types, such as polyoxyethylene laurylamino ether; Alkylamide types, such as polyoxyethylene lauric acid amide; polypropylene glycol ether types such as polyoxyethylene polyoxypropylene ether; Alkanolamide types, such as lauric-acid diethanolamide and oleic-acid diethanolamide; Allylphenyl ether types, such as polyoxyalkylene allylphenyl ether, etc. are mentioned.

The PVA film can contain 1 type(s) or 2 or more types of these surfactant. Among these surfactants, nonionic surfactants are preferable, and especially alkanolamide-type surfactants are more preferable, and aliphatic carboxylic acids (for example, having 8 carbon atoms) Dialkanolamides (eg, diethanolamide, etc.) of -30 saturated or unsaturated aliphatic carboxylic acid etc.) are more preferable.

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 there is too little content rate of surfactant, there exists a possibility that the handleability of a PVA film and the peelability from the film forming apparatus at the time of manufacturing a PVA film may deteriorate more or blocking may generate|occur|produce. From this viewpoint, it is more preferable that the content rate of surfactant is 0.02 mass % or more, and 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 impair the uniformity of a film, and it will become easy to generate|occur|produce the problem which produces optical nonuniformity in the polarizing plate obtained for that reason, 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 antioxidant, a ultraviolet absorber, a lubricant, a coloring agent, a preservative, a mildew-proof agent, other high molecular compounds other than the above-mentioned component, and water|moisture content as needed. The PVA film may 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 in which the thickness and width|variety of the film after film forming become more uniform can be employ|adopted preferably, For example, above-mentioned PVA which comprises a PVA film, and a plasticizer further as needed. , a surfactant and one or two or more of the above other components dissolved in a liquid medium, a film forming stock solution or PVA, and, if necessary, additionally a plasticizer, a surfactant, one or two or more of the above other components and a liquid medium It can be prepared using a film forming undiluted solution containing molten PVA. When the said film forming undiluted|stock solution contains at least 1 sort(s) of a plasticizer, surfactant, and said other component, it is preferable that these components are mixed uniformly.

Examples of the liquid medium used for preparing the film forming stock solution include 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, Among these, 1 type, or 2 or more types can be used. Among these, water and dimethyl sulfoxide are preferable, and water is more preferable.

The volatile fraction of the film forming undiluted solution (the content ratio in the film forming undiluted solution of volatile components such as a liquid medium removed by volatilization or evaporation during film forming) also varies depending on the polymerization degree of PVA, the film forming method, the film forming conditions, etc., but 20 mass % or more, more preferably 25 mass% or more, still more preferably 30 mass% or more, particularly preferably 40 mass% or more, and more preferably 95 mass% or less, more preferably 90 mass% or less and 85 mass% or less is more preferable, and it is especially preferable that it is 70 mass% or less. When the volatile fraction of the film forming undiluted solution is equal to or greater than the lower limit, the viscosity of the film forming undiluted solution does not become excessively high, filtration and defoaming during preparation of the film forming undiluted solution are performed smoothly, and the production of a PVA film with few foreign substances and defects becomes easy. On the other hand, when the volatile fraction of the film-forming undiluted solution is below the said upper limit, the density|concentration of the film-forming undiluted|stock solution does not become low too much, and manufacture of an industrial PVA film becomes easy.

As a film forming method at the time of forming a PVA film into a film using the above-mentioned 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. These film forming methods may employ|adopt only 1 type, and may employ|adopt them 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 a viewpoint of obtaining a favorable PVA film.

As an example of a specific manufacturing method for a PVA film, for example, using a known membrane discharging device (membrane casting device) such as a T-type slit die, a hopper plate, an I-die, and a lip coater die, the above film forming stock solution is transferred to the uppermost A volatile component from one side of a film that is uniformly discharged or cast on the peripheral surface of a rotating heated roll (or belt) and is discharged or cast on the peripheral surface of this first roll (or belt). A method of evaporating to dryness, then further drying on the peripheral surface of one or a plurality of rotating heated rolls arranged on the downstream side thereof, or passing through a hot air drying apparatus is industrially preferable. can You may perform drying by the heated roll and drying by a hot-air drying apparatus combining 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, by using such a thin polarizing film, a thin polarizing plate can be manufactured efficiently. Conventionally, when a PVA film is thin and the winding length is long, there existed a problem that fine wrinkles and eccentricity generate|occur|produced and a roll with a favorable external shape was not obtained. On the other hand, according to this invention, even if it is a case where a PVA film is thin and winding length is long, wrinkles and eccentricity do not generate|occur|produce easily, and the roll of a PVA film with a favorable external shape is obtained. Therefore, when the thickness of a PVA film is 45 micrometers or less, the effect of this invention is acquired remarkably. From the above viewpoints, 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 very thin, there exists a tendency for secondary processing of the film processed into 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 still 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 to be manufactured, have a large area, the thing 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 fine wrinkles and eccentricity were generated, and a roll with a favorable external shape was not obtained. On the other hand, according to this invention, even if it is a case where a PVA film is thin and a winding length is long, wrinkles and eccentricity do not generate|occur|produce easily, and the roll of a PVA film with a favorable external 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. From the above viewpoint, 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 the upper limit of the length of a PVA film, It is preferable that it is 30,000 m or less, and it is more preferable that it is 22,000 m or less from the point etc. which a roll of a PVA film better than an external thing can be easily obtained. The length of a PVA film may be 18,000 m or less, Furthermore, 15,000 m or less may be sufficient as it.

There is no restriction|limiting in particular in the width|variety of a PVA film, For example, it can be 50 cm or more. By the way, in general, in the roll obtained, it exists in the tendency which wrinkles and eccentricity generate|occur|produce easily, so that the width|variety of a PVA film is wide. On the other hand, according to this invention, since generation|occurrence|production of wrinkles and eccentricity is reduced even if it is a case where the width|variety of a PVA film is wide, the effect of this invention is acquired more notably in such a case. Moreover, the wide polarizing film which can respond to the enlargement of LCD by using a wide PVA film can be manufactured. From these points, 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 may be 3.5 m or more. The upper limit of the width of the PVA film is not particularly limited, but from the viewpoint of easily obtaining a roll of a PVA film having a better external shape, the width is preferably 6 m or less, more preferably 5 m or less, more preferably 4.2 m or less desirable. It is preferable that it is 4 m or less at the point from which the PVA film which was especially excellent in an external shape is obtained, and it is more preferable that it is 3.8 m or less.

In the roll of this invention, the average space|interval between adjacent films (between the PVA films adjacent to 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 it is a case where a PVA film is thin and winding length is long, wrinkles and eccentricity do not generate|occur|produce easily, and the roll with a favorable external appearance is obtained. From such a viewpoint, 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 still more preferable that it is 4.2 micrometers or less, 4 micrometers or less, Furthermore, 3.8 micrometers or less may be sufficient. In addition, when the average interval between adjacent films is less than 2 μm, blocking occurs and fluctuations occur during unwinding of the PVA film, or appearance abnormalities such as wrinkles occur in the film due to tightly winding the PVA film roll. It is easy to cause the problem that uniformity is impaired. From such a viewpoint, the average spacing is preferably 2 µm or more, more preferably 2.5 µm or more, still more preferably 3 µm or more, and particularly preferably 3.5 µm or more.

The average distance between the adjacent films can be obtained by the following method. That is, in an outer diameter H (m) roll formed by winding a PVA film having a length L (m) and a thickness M (µm) on a cylindrical core having an outer diameter D (m), the average spacing N (µm) between the adjacent films. ) is the following formula:

N = {(π/4)(H ² - D ² )/L} × 10 ⁶ - M

can be calculated 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 this invention below, since the said roll can be manufactured efficiently, it is preferable. That is, the manufacturing method of the present invention is a manufacturing method of 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,

(a) In the winding process of the PVA film, the PVA film is brought into contact with the outer peripheral surface of the film roll (film state part) formed of the already wound PVA film, with the contact roll arranged substantially parallel to the axial direction of the film roll. wind 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 winding speed is 30 m/min or less, it is a manufacturing method.

The manufacturing method of this invention WHEREIN: As a PVA film used for manufacture of a roll, the thing mentioned above can be used as a PVA film used for manufacture of the roll of this invention.

In the manufacturing method of this invention, in the winding-up process of a PVA film, while making the contact roll arrange|positioned substantially parallel to the axial direction of the said film roll contact with the outer peripheral surface of the film roll formed with the already wound PVA film, a PVA film Adopt a touch winding method to wind the 1 is a schematic diagram showing an example of the touch winding method. As shown in FIG. 1, on the outer peripheral surface of the film roll 1 formed of the PVA film 3 already wound, the contact roll 2 arrange|positioned substantially parallel with respect to the axial direction of the said film roll 1 is A roll is produced by further winding the PVA film 3 in a state 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) where the PVA film (3) is wound on the film roll (1), it is preferable that the film roll (1) and the contact roll (2) are in contact over the entire axial direction of the film roll (1). Do. Also, as a method separate from the touch winding method, a near winding method shown schematically 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) between the outer peripheral surface of the film roll 1 formed of the already wound PVA film and the contact roll 2 is has been maintained

The length of the contact roll 2 is not particularly limited, but it is preferably longer than the width of the film roll 1 within the range of 3 to 200 cm, more preferably within the range of 5 to 100 cm, and more preferably from 10 to More preferably, it is long within the range of 50 cm.

Although there is no restriction|limiting in particular in the diameter of the contact roll 2, From a viewpoint of intensity|strength, handleability, etc., it is preferable that the outer diameter exists in the range of 50-1000 mm, It is more preferable that it exists in the range of 75-800 mm, It is 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 the present invention, when the PVA film 3 is wound, the pressure between the film roll 1 and the contact roll 2 (pressure to press the contact roll 2 to the film roll 1) is applied to the film roll (1) It is set in the range of 3-30 N per 1 m of length in the axial direction. Hereinafter, the said pressure may be called "winding contact pressure", and "N/m" may be used as a unit for indicating that it is the pressure per 1 m of length in the axial direction of a film roll. The roll of this invention can be manufactured efficiently by making a winding contact pressure into the said range. 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 more preferable that it is 8 N/m or less. From a viewpoint of being able to manufacture the roll of this invention more efficiently, it is preferable that it is 3.5 N/m or more, 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 shall be 30 m/min or less. By setting the winding speed to 30 m/min or less, the roll of the present invention can be efficiently manufactured. From this viewpoint, it is preferable that the said winding speed is 25 m/min or less. From a viewpoint of being able to manufacture the roll of this invention more efficiently, it is preferable that it is 9 m/min or more, and, as for the said winding speed, it is more preferable that it is 15 m/min or more.

In the manufacturing method of this invention, the winding tension at the time of winding up the PVA film 3 (tension applied in the longitudinal direction of the PVA film 3 when winding up a PVA film) is the film formed from the PVA film already wound. It is preferable to set it as 80 N or less per 1 m of length in the axial direction of the roll 1 . Hereinafter, "N/m" may be used as a unit for indicating that it is a winding tension per 1 m of length in the axial direction of the film roll 1 . The roll of this invention can be manufactured more efficiently by making winding tension|tensile_strength into the said range. From this viewpoint, it is more preferable that the said winding tension is 75 N/m or less, and it is still more preferable that it is 70 N/m or less. From the viewpoint of more efficiently manufacturing the roll of the present invention, 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, and 50 N /m or more is particularly preferred.

3 is a film roll 1 viewed from the direction 11 of the tangent line 10 of the contact roll 2 at a position where the contact roll 2 is in contact with the film roll 1 in FIG. 1 ; It is an example of the schematic of the contact roll 2 . In the manufacturing method of the present invention, the parallelism (A) between the axis of the film roll 1 and the axis of the contact roll 2 obtained from the distance between the axis of the film roll 1 and the axis of the contact roll 2 is 0.7 mm It is preferable that it is below. Thereby, in the position 5 where the PVA film 3 is wound around 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 Therefore, the roll of the present invention having a good external shape can be manufactured with better efficiency. The parallelism (A) is more preferably 0.5 mm or less, and still more preferably 0.2 mm or less. In the present invention, the parallelism (A) is the distance (b - a) from one end (b) of the axis (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). to the nearest location. Distances (b - a) and distances (b' - a') can be measured using a dial gauge.

4 : is an example of the schematic of the film roll 1 and the contact roll 2 seen from the horizontal direction 12 in FIG. In the manufacturing method of the present invention, a film obtained from the horizontality of the axis of the film roll 1 and the horizontality of the axis of the contact roll 2 when viewed from the horizontal direction of the film roll 1 and 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 where the PVA film 3 is wound around 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 Therefore, the roll of the present invention having a good external shape can be manufactured with better efficiency. The parallelism (B) is more preferably 0.15 mm or less, and still more preferably 0.1 mm or less. The parallelism (B) in this invention is demonstrated concretely below. The axis 7 of the contact roll 2 is projected on a plane comprising the axis 6 of the film roll 1 and also perpendicular to the horizontal plane. And the distance (d-c) from the one end d of the axis 7 of the contact roll 2 to the axis 6 of the film roll 1 in a projection surface, and the axis|shaft of the contact roll 2 Let the difference of the distance (d'-c') from the other end (d') of (7) to the axis|shaft 6 of the film roll 1 be 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). to the nearest location. Parallelism (B) can be calculated|required by measuring the horizontality of the axial direction of the film roll 1 and the contact roll 2 using a level, respectively.

The roll obtained in this way WHEREIN: It is preferable that the average space|interval between adjacent films is 5 micrometers or less. When the said average space|interval is 5 micrometers or less, even if it is a case where a PVA film is thin and winding length is long, wrinkles and eccentricity do not generate|occur|produce easily, and the roll with a favorable external appearance is obtained. According to the manufacturing method of this invention, it is possible to control the said average space|interval easily. 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 still 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 spacing is 2 micrometers or more, It is more preferable that it is 2.5 micrometers or more, It is still more preferable that it is 3 micrometers or more, and its 3.5 micrometers or more are especially preferable.

There is no particular limitation on the use of the PVA film in the roll of the present invention, for example, a film for drug packaging, a base film for hydraulic transfer, a substrate film for embroidery, a release film for artificial marble molding, a film for seed packaging, and a waste receiving bag It can be used for the use of various water-soluble films, such as a film for use. ADVANTAGE OF THE INVENTION According to this invention, even when a PVA film is thin and a winding length is long, wrinkles and eccentricity do not generate|occur|produce easily, and the roll with a favorable external shape is provided. If such a roll is used, even if it is a large area, the optical film excellent in the uniformity of optical performance can be manufactured continuously with favorable efficiency. 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 in particular at the time of manufacturing a polarizing film using a PVA film is not restrict|limited, Any conventionally known method may be employ|adopted. In such a method, for example, using the PVA film unwound from the roll of this invention, dyeing and uniaxial stretching are performed, or uniaxial stretching with respect to the PVA film containing the dye unwound from the roll of this invention. and methods of carrying out As a more specific method for manufacturing the polarizing film, swelling, dyeing, uniaxial stretching, and, if necessary, 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 it In this case, the order of each treatment such as swelling, dyeing, crosslinking treatment, uniaxial stretching, and fixing treatment is not particularly limited, and one or two or more treatments may be performed simultaneously. In addition, one or two or more of each treatment may be performed twice or more.

The manufactured polarizing film is normally optically transparent on the single side|surface or both surfaces, and it bonds together the protective film which has mechanical strength, It sets it as the form of a polarizing plate, and is used. As the protective film, a cellulose triacetate (TAC) film, a cycloolefin polymer (COP) film, a cellulose acetate/butyrate (CAB) film, an acrylic film, a polyester film, or the like is used. Moreover, as an adhesive agent for adhesion, a PVA type adhesive agent, a urethane type adhesive agent, etc. are mentioned, Especially, PVA type adhesive agent is preferable.

After coating adhesives, such as an acrylic type, the polarizing plate obtained by making it above can be bonded together to a glass substrate and can be used as an LCD component. Simultaneously, you may bond together retardation film, a viewing angle improvement film, a brightness improvement film, etc.

[Example]

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

[Evaluation of appearance shape]

The appearance shape of the roll was evaluated according to the following criteria.

A: No wrinkles or eccentricity, so the appearance is good

B: Very few wrinkles are observed, but eccentricity is not generated, and the appearance shape is good.

C: The appearance is poor due to the occurrence of fine wrinkles or eccentricity.

[Evaluation of optical non-uniformity]

Sample films of 15 cm x 5 cm were sampled from the center and both ends of the film rolls obtained in Examples and Comparative Examples below. About the said PVA film, the polarizing film was manufactured by performing a swelling process, a dyeing|staining process, a bridge|crosslinking process, an extending|stretching process, a fixed treatment process, and a drying process. Four sample films were mounted on a stretching jig. While being immersed in water with a temperature of 30 degreeC for 1 minute, it uniaxially stretched (1st stage|stage extending|stretching) to the longitudinal direction (MD) at 2.2 times of the original length. Thereafter, uniaxial stretching in the longitudinal direction (MD) to 3.2 times the original length ( 2nd stage stretching) was carried out. Subsequently, while immersing in a crosslinking bath having a temperature of 30°C containing boric acid at a concentration of 3.0% by mass and potassium iodide at a concentration of 3.0% for 2 minutes, uniaxial stretching in the longitudinal direction (MD) to 3.6 times the original length (3rd stage stretching) ) was done. Further, uniaxial stretching (4th stage stretching) is carried out while immersing in a stretching bath having a temperature of 55°C containing boric acid at a concentration of 4.0 mass% and potassium iodide at a concentration of 5.0 mass%, and when 2 sheets of the 4 films are cut 2 uncut sheets were taken out of the stretching bath. Thereafter, the film is washed by immersion for 5 seconds in a fixed treatment bath at a temperature of 22°C containing boric acid at a concentration of 1.5% by mass and potassium iodide at a concentration of 5% by mass, followed by drying for 240 seconds with a dryer at 60°C, 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 1 sheet of polarizing plate (43.5% of single transmittance, and 99.9% of polarization degree). Using a backlight with a luminance of 15000 candela, the difference in light and shade resulting from the non-uniformity in transmittance (optical non-uniformity) between the film sampled from the center portion of the film roll and the film sampled from the edge portion was observed, and the optical non-uniformity was evaluated based on the following criteria. .

A: The difference in light and shade due to the difference in transmittance between the film sampled from the central portion and the film sampled from both ends is not seen and is uniform.

B: There is a slight difference in light and shade due to the difference in transmittance between the film sampled from the central portion and the film sampled from both ends.

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

Example 1

PVA film composed of PVA with a degree of polymerization of 2,400 and a degree of saponification of 99 mol% or more (30 µm in thickness, 20,000 m in length, 4.2 m in width, contains 10% by mass of glycerin as a plasticizer, and 0.1% by mass of diethanolamide lauric acid as a surfactant contains) was wound around a cylindrical core to prepare a roll. In addition, as a winding method, a contact roll (outer diameter: 210 mm, roll length: 4950 mm) arranged substantially parallel to the axial direction of the film roll on the outer peripheral surface of the film roll formed of the already wound PVA film is brought into contact with A touch winding method of winding a PVA film was adopted. Specific conditions are shown in Table 1.

The average space|interval between adjacent films in the obtained roll was 4.15 micrometers. About the roll, the external shape was evaluated by the said method. Moreover, by the said method, manufacture of a polarizing film and evaluation of optical nonuniformity were performed. Table 1 shows the above results.

Examples 2 to 8, Comparative Examples 2 to 5

A roll was manufactured and evaluated 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 production conditions of the roll were changed as shown in Table 1. did The results are shown in Table 1.

[Comparative Example 1]

PVA film composed of PVA with a degree of polymerization of 2,400 and a degree of saponification of 99 mol% or more (30 µm in thickness, 20,000 m in length, 3.3 m in width, contains 10% by mass of glycerin as a plasticizer, and 0.1% by mass of diethanolamide lauric acid as a surfactant contains) was wound around a cylindrical core to prepare a roll. In addition, as a winding system, the near winding system was employ|adopted. Specific conditions are shown below.

[Contact Roll]

Shaft diameter: 210 mm

Roll Length: 4950 mm

[winding conditions]

Winding contact 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]

A PVA film composed of PVA with a degree of polymerization of 2,400 and a degree of saponification of 99 mol% or more (60 µm in thickness, 9,600 m in length, 4.2 m in width, contains 10% by mass of glycerin as a plasticizer, and 0.1% by mass of diethanolamide lauric acid as a surfactant contains) was wound around a cylindrical core to prepare a roll. In addition, as a winding method, the near winding method was employ|adopted. Specific conditions are shown below.

[Contact Roll]

Shaft diameter: 210 mm

Roll Length: 4950 mm

[winding conditions]

Winding contact 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: the axis of the film roll
7: the axis of the contact roll
8, 9: the end of the PVA film
10: tangent
11, 12: direction

Claims (10)

A method for producing a roll in which a polyvinyl alcohol film having a thickness of 35 μm or less and a length of 2,000 m or more is wound,
(a) In the winding process of the polyvinyl alcohol film, the outer peripheral surface of the film roll formed of the already wound polyvinyl alcohol film is brought into contact with a contact roll arranged parallel to the axial direction of the film roll, while the polyvinyl alcohol film is applied wind 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 winding speed is 30 m/min or less,
In the roll on which the polyvinyl alcohol film is wound, the average interval between adjacent films is 2 µm or more and 5 µm or less, and the plasticizer content in the polyvinyl alcohol film is 5 to 30 mass%, and the polyvinyl alcohol film is A method for producing a roll in which the vinyl alcohol film is a raw film for polarizing film production. delete The method of claim 1,
The manufacturing method of the roll whose content rate of the surfactant in a polyvinyl alcohol film is 0.01-1.0 mass %. The method of claim 1,
The manufacturing method of the roll whose width|variety of a polyvinyl alcohol film is 2 m or more. delete delete delete The method of claim 1,
A method for producing a roll, wherein the winding tension is 80 N or less per 1 m of the length in the axial direction of the film roll. The method of claim 1,
The manufacturing method of a roll whose parallelism A of the axis|shaft of a film roll and the axis|shaft of a contact roll calculated|required from the distance between the axis|shaft of a film roll and the axis|shaft of a contact roll is 0.7 mm or less. The method of claim 1,
A method for producing a roll, wherein 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 is viewed in the horizontal direction, obtained from the horizontality of the axis of the film roll and the horizontality of the axis of the contact roll, is 0.2 mm or less.

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