WO2021117801A1 - 光学用ポリビニルアルコールフィルムの製造方法 - Google Patents

光学用ポリビニルアルコールフィルムの製造方法 Download PDF

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Publication number
WO2021117801A1
WO2021117801A1 PCT/JP2020/045996 JP2020045996W WO2021117801A1 WO 2021117801 A1 WO2021117801 A1 WO 2021117801A1 JP 2020045996 W JP2020045996 W JP 2020045996W WO 2021117801 A1 WO2021117801 A1 WO 2021117801A1
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Prior art keywords
film
roll
drying
drying roll
pva
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PCT/JP2020/045996
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English (en)
French (fr)
Japanese (ja)
Inventor
宏希 川嶋
涼平 梅本
勝啓 高藤
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株式会社クラレ
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Priority to CN202080085648.7A priority Critical patent/CN114761200B/zh
Priority to JP2021564022A priority patent/JP7375042B2/ja
Priority to KR1020227018278A priority patent/KR20220113932A/ko
Publication of WO2021117801A1 publication Critical patent/WO2021117801A1/ja

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D11/00—Producing optical elements, e.g. lenses or prisms
    • B29D11/0074—Production of other optical elements not provided for in B29D11/00009- B29D11/0073
    • B29D11/00788—Producing optical films
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C41/00—Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor
    • B29C41/24—Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor for making articles of indefinite length
    • B29C41/26—Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor for making articles of indefinite length by depositing flowable material on a rotating drum
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C41/00—Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor
    • B29C41/34—Component parts, details or accessories; Auxiliary operations
    • B29C41/46—Heating or cooling
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D7/00—Producing flat articles, e.g. films or sheets
    • B29D7/01—Films or sheets
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2029/00—Use of polyvinylalcohols, polyvinylethers, polyvinylaldehydes, polyvinylketones or polyvinylketals or derivatives thereof as moulding material
    • B29K2029/04—PVOH, i.e. polyvinyl alcohol

Definitions

  • the present invention relates to a method for producing an optical polyvinyl alcohol film (hereinafter, "polyvinyl alcohol” may be abbreviated as "PVA”). More specifically, the present invention relates to a method for producing a wide-width polyvinyl alcohol film for optics.
  • PVA optical polyvinyl alcohol film
  • a polarizing plate having a light transmitting and shielding function is a basic component of a liquid crystal display (LCD) together with a liquid crystal having a light switching function.
  • LCD liquid crystal display
  • the fields of application of this LCD range from small devices such as calculators and wristwatches in the early days of development to laptop computers, word processors, LCD projectors, in-vehicle navigation systems, LCD TVs, personal phones, and measurements used indoors and outdoors. It has spread widely to equipment. With the expansion of the application fields of LCDs, there is a demand for a neutral gray polarizing plate having higher polarization performance than conventional products and excellent hue in order to improve color display quality.
  • the polarizing plate is generally obtained by uniaxially stretching and dyeing a PVA film, or by dyeing and uniaxially stretching and then fixing with a boron compound (in some cases, two of dyeing, stretching and fixing treatment).
  • a protective film such as a cellulose triacetate (TAC) film or a cellulose acetic acid / butyrate (CAB) film is attached to the obtained polarizing film (which may be performed at the same time).
  • Patent Document 1 describes a method of using a drying roll in which the outer diameter of the central portion is larger than the outer diameters of both ends by a specific amount as the drying roll. According to the method, an unprecedented PVA film in which the amount of elongation in the length direction in water on both ends in the width direction is a specific amount larger than the amount of elongation in the central portion is smoothly and continuously produced. It is described that the PVA can be used to easily produce a polarizing film having less uneven transmittance between the central portion and the edge portion.
  • an object of the present invention is to provide a manufacturing method capable of manufacturing a wide-width optical PVA film.
  • a film-forming device having a plurality of drying rolls whose rotation axes are parallel to each other is used, and the film-forming device is located on the most upstream side of the film-forming device.
  • a film-forming stock solution containing PVA is discharged into a film on one drying roll to dry it, and the obtained film is further dried by a drying roll after the second drying roll following the downstream side of the first drying roll to further dry PVA.
  • the present invention [1] A method for producing an optical polyvinyl alcohol film, which uses a film-forming device including a plurality of drying rolls whose rotation axes are parallel to each other, and is placed on a first drying roll located on the most upstream side of the film-forming device.
  • the film-forming stock solution containing polyvinyl alcohol is discharged into a film and dried, and the obtained film is further dried by a drying roll after the second drying roll following the downstream side of the first drying roll, and the second drying At least one of the drying rolls after the roll is a different-diameter drying roll, and in at least a part of the region at a position of 50 mm or more and 250 mm or less from both ends in the width direction to the central part in the width direction of the film in contact with the different-diameter drying roll.
  • a method for producing an optical polyvinyl alcohol film wherein the outer diameter of the different-diameter drying roll is 1.0 mm to 3.0 mm larger than the outer diameter of the central portion in the width direction; [2] The method for producing an optical polyvinyl alcohol film according to the above [1], which obtains a polyvinyl alcohol film having a width of 2 m or more; [3] The method for producing an optical polyvinyl alcohol film according to the above [1] or [2], wherein the width of the region having a large outer diameter is 10 to 55 mm; [4] The polyvinyl alcohol film for optics according to the above [1] to [3], wherein the deformed drying roll is formed by attaching a fluorine-based resin tape to a metal roll to provide a region having a large outer diameter.
  • the film forming apparatus includes a plurality of different-diameter drying rolls having the same width, and the downstream side of the different-diameter drying roll has a region having a larger outer diameter located on the center side in the width direction.
  • a manufacturing method capable of smoothly and continuously manufacturing a wide optical PVA film.
  • PVA forming the PVA film examples include PVA (unmodified PVA) obtained by saponifying polyvinyl ester obtained by polymerizing vinyl ester, modified PVA obtained by graft-copolymerizing a comonome on the main chain of PVA, and vinyl.
  • PVA unmodified PVA
  • the amount of modification in PVA is preferably 15 mol% or less, and more preferably 5 mol% or less.
  • vinyl ester used in the production of PVA examples include vinyl acetate, vinyl formate, vinyl laurate, vinyl propionate, vinyl butyrate, vinyl pivalate, vinyl versatic acid, vinyl stearate, vinyl benzoate and the like. Can be mentioned. These vinyl esters can be used alone or in combination. Of these vinyl esters, vinyl acetate is preferable from the viewpoint of productivity.
  • Examples of the comonomer described above include olefins having 2 to 30 carbon atoms ( ⁇ -olefin and the like) such as ethylene, propylene, 1-butyl and isobutene; acrylate or a salt thereof; methyl acrylate, ethyl acrylate, etc.
  • Acrylic acid esters such as n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, i-butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, octadecyl acrylate, etc.
  • acrylic acid having 1 to 18 carbon atoms, etc. methacrylic acid or a salt thereof; methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, n-butyl methacrylate, i methacrylate.
  • -Methyl acrylates such as butyl, t-butyl methacrylate, 2-ethylhexyl methacrylate, dodecyl methacrylate, octadecyl methacrylate (for example, 1-18 alkyl esters of methacrylic acid); acrylamide, N-methylacrylamide , N-ethylacrylamide, N, N-dimethylacrylamide, diacetoneacrylamide, acrylamidepropanesulfonic acid or salts thereof, acrylamide propyldimethylamine or salts thereof, acrylamide derivatives such as N-methylolacrylamide or derivatives thereof; methacrylicamide, N- Methalamide derivatives such as methylmethacrylate, N-ethylmethacrylate, methacrylamide propanesulfonic acid or a salt thereof, methacrylatepropyldimethylamine or a salt thereof, N-methylolmethacrylate or a derivative thereof; N-vinylformamide
  • Vinyl 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; maleic acid, itaconic acid and the like.
  • Desaturated dicarboxylic acid, a salt thereof or a derivative thereof, such as an ester thereof; Lyl compounds; isopropenyl acetate; unsaturated sulfonic acids or derivatives thereof and the like can be mentioned.
  • ⁇ -olefins are preferable, and ethylene is particularly preferable.
  • the average degree of polymerization of PVA forming the PVA film is preferably 1000 or more, more preferably 1500 or more, and even more preferably 2000 or more, from the viewpoint of the polarization performance and durability of the obtained polarizing film.
  • the average degree of polymerization is preferably 8000 or less, and particularly preferably 6000 or less.
  • the "average degree of polymerization" of PVA in the present specification means the average degree of polymerization measured according to JIS K6726-1994, and is the limit measured in water at 30 ° C. after reseminating and purifying PVA. Obtained from the viscosity.
  • the degree of saponification of the PVA forming the PVA film is preferably 95.0 mol% or more, more preferably 98.0 mol% or more, and 99.0 mol% from the viewpoint of the polarization performance and durability of the obtained polarizing film.
  • the above is more preferable, and 99.3 mol% or more is most preferable.
  • the "degree of saponification" of PVA in the present specification refers to the vinyl with respect to the total number of moles of structural units (typically vinyl ester units) that can be converted into vinyl alcohol units by saponification and vinyl alcohol units. The ratio (mol%) of the number of moles of alcohol units.
  • the degree of saponification of PVA can be measured according to the description of JIS K6726-1994.
  • the method for producing an optical PVA film of the present invention includes a plurality of drying rolls whose rotation axes are parallel to each other (referred to as a first drying roll, a second drying roll, and so on, sequentially from the most upstream side to the downstream side).
  • the film-forming apparatus provided with the above-mentioned film forming apparatus is used, and a film-forming stock solution containing PVA is discharged into a film on a first drying roll located on the most upstream side of the film-forming apparatus and dried, and the obtained film is produced by the first drying roll.
  • Further drying is performed by the drying rolls after the second drying roll following the downstream side of the drying roll, and at least one of the drying rolls after the second drying roll is a different diameter drying roll, and the film is in contact with the different diameter drying roll.
  • the outer diameter of the different diameter drying roll in at least a part of the region at a position of 50 mm or more and 250 mm or less from both ends in the width direction to the center portion in the width direction is 1.0 mm to 3.0 mm larger than the outer diameter of the center portion in the width direction. It is a thing. According to the manufacturing method of the present invention, an optical PVA film can be smoothly and continuously manufactured.
  • a film-forming device including a plurality of drying rolls whose rotation axes are parallel to each other is used, and a film-forming stock solution containing PVA is placed on a first drying roll located on the most upstream side of the film-forming device.
  • the PVA film is formed by discharging the film into a film and drying it, and further drying the obtained film with a drying roll after the second drying roll following the downstream side of the first drying roll.
  • the number of drying rolls (the number of drying rolls including the first drying roll (cast roll)) is preferably 9 to 30, and more preferably 12 to 26.
  • the drying roll referred to in the present invention is a roll that heats a film in contact with the dry roll. It is distinguished from guide rolls that do not have a heating function and take-up rolls for winding film.
  • the dry roll is preferably formed of, for example, a metal such as nickel, chromium, copper, iron, or stainless steel, and in particular, the surface of the dry roll is formed of a metal material that is resistant to corrosion and has a mirror gloss. Is more preferable. Further, in order to enhance the durability of the dry roll, a dry roll formed by plating a single layer or a combination of two or more nickel layers, a chromium layer, a nickel / chromium alloy layer and the like may be used.
  • the heating direction when drying the film in the process from the first drying roll to the final drying roll is not particularly limited, but since the film can be dried more uniformly, the first drying can be performed on any part of the film.
  • a film surface that comes into contact with the roll hereinafter, may be referred to as a "first dry roll contact surface”
  • a film surface that does not come into contact with the first dry roll hereinafter, may be referred to as a "first dry roll non-contact surface”
  • a film-forming stock solution containing PVA onto the first drying roll (cast roll) of the film-forming device in the form of a film for example, a T-shaped slit die, a hopper plate, an I-die, a lip coater die, or the like is used.
  • a known film-like discharge device film-like flow device may be used to discharge (spread) the film-forming stock solution containing PVA onto the first drying roll in the form of a film.
  • the membrane-forming stock solution containing PVA film can be prepared by mixing PVA with a liquid medium to make a solution, or melting PVA pellets containing a liquid medium or the like to make a melt.
  • the liquid medium used at that time include water, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, ethylenediamine, diethylenetriamine, etc., and one of these liquid media is used alone. Or two or more of them may be used in combination. Among these, water, dimethyl sulfoxide, or a mixture of both is preferably used, and water is more preferably used.
  • a plasticizer to the film-forming stock solution from the viewpoints of promoting dissolution and melting of PVA in a liquid medium, improving process passability during PVA film production, and improving the stretchability of the obtained PVA film.
  • Polyhydric alcohols are preferably used as the plasticizer, and examples thereof include ethylene glycol, glycerin, diglycerin, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, and trimethylolpropane.
  • One type may be used alone, or two or more types may be used in combination.
  • one or more of glycerin, diglycerin and ethylene glycol are preferable from the viewpoint of excellent effect of improving stretchability.
  • the amount of the plasticizer added is preferably 0 to 30 parts by mass, more preferably 3 to 25 parts by mass, and particularly preferably 5 to 20 parts by mass with respect to 100 parts by mass of PVA.
  • the amount of the plasticizer added is 30 parts by mass or less with respect to 100 parts by mass of PVA, the obtained PVA film does not become too soft and it is possible to suppress deterioration of handleability.
  • a surfactant to the film-forming stock solution from the viewpoints of improving the releasability from the dry roll when producing the PVA film and the handleability of the obtained PVA film.
  • the type of the surfactant is not particularly limited, but an anionic surfactant or a nonionic surfactant is preferably used.
  • anionic surfactant for example, a carboxylic acid type such as potassium laurate, a sulfate ester type such as octyl sulfate, and a sulfonic acid type such as dodecylbenzene sulfonate are suitable.
  • a carboxylic acid type such as potassium laurate
  • a sulfate ester type such as octyl sulfate
  • a sulfonic acid type such as dodecylbenzene sulfonate
  • nonionic surfactant examples include an alkyl ether type such as polyoxyethylene oleyl ether, an alkylphenyl ether type such as polyoxyethylene octylphenyl ether, an alkyl ester type such as polyoxyethylene laurate, and polyoxyethylene.
  • Alkylamine type such as laurylamino ether
  • alkylamide type such as polyoxyethylene lauric acid amide
  • polypropylene glycol ether type such as polyoxyethylene polyoxypropylene ether
  • alkanolamide type such as lauric acid diethanolamide and oleic acid diethanolamide
  • Nonionic surfactants such as allylphenyl ether type such as polyoxyalkylene allylphenyl ether are suitable. These surfactants may be used alone or in combination of two or more.
  • the amount of the surfactant added is preferably 0.01 to 1 part by mass, more preferably 0.02 to 0.5 part by mass, and particularly preferably 0.05 to 0.3 part by mass with respect to 100 parts by mass of PVA.
  • the amount of the surfactant added is 0.01 parts by mass or more with respect to 100 parts by mass of PVA, the effect of improving film-forming property, peelability and the like is likely to appear.
  • it exceeds 1 part by mass the surfactant elutes on the film surface and causes blocking, or the handleability tends to be deteriorated.
  • the film-forming stock solution contains various additives such as stabilizers (antioxidants, ultraviolet absorbers, heat stabilizers, etc.), compatibilizers, antiblocking agents, flame retardants, antistatic agents, etc. It may contain a lubricant, a dispersant, a fluidizing agent, an antibacterial agent and the like. These additives may be used alone or in combination of two or more.
  • the volatile fraction of the film-forming stock solution used for producing the PVA film is preferably 50 to 90% by mass, more preferably 55 to 80% by mass, further preferably 60 to 75% by mass, and particularly preferably 65 to 70% by mass.
  • the volatile fraction of the film-forming stock solution is less than 50% by mass, the viscosity of the film-forming stock solution becomes too high, which may make filtration or defoaming difficult, or the film-forming itself may become difficult.
  • the volatile content of the film-forming stock solution exceeds 90% by mass, the viscosity may become too low and the uniformity of the thickness of the PVA film may be impaired.
  • the "volatile fraction of the film-forming stock solution" in the present invention means the volatile fraction obtained by the following formula (I).
  • the roll surface temperature of the first drying roll is preferably 80 to 120 ° C., more preferably 85 to 105 ° C. from the viewpoint of uniform drying property, drying speed and the like. ..
  • the film-forming stock solution discharged in the form of a film may be dried only by heating from the first drying roll, but at the same time as heating by the first drying roll, the non-contact surface of the first drying roll It is preferable to blow hot air on the film and apply heat from both sides of the film to dry the film from the viewpoints of uniform drying property and drying speed.
  • the temperature of the hot air blown onto the non-contact surface of the first drying roll of the film is preferably 50 to 150 ° C., more preferably 70 to 120 ° C., and 80. It is more preferably ⁇ 95 ° C. If the temperature of the hot air blown onto the non-contact surface of the first drying roll of the film is too low, dew condensation such as water vapor may occur, and the water droplets may fall on the film to cause defects in the finally obtained PVA film. On the other hand, if the temperature is too high, dry spots may occur along the direction of the hot air, and the thickness spots of the finally obtained PVA film may occur.
  • the dew point temperature of the hot air blown onto the non-contact surface of the first drying roll of the film is preferably 5 to 20 ° C, more preferably 10 to 15 ° C, and even more preferably 11 to 13 ° C. If the dew point temperature of the hot air blown onto the non-contact surface of the first drying roll of the film is too low, the drying efficiency and uniform drying property tend to decrease, while if the dew point temperature is too high, foaming tends to occur.
  • the method for blowing hot air onto the non-contact surface of the first dry roll of the film is not particularly limited, and hot air having a uniform wind speed and a uniform temperature is uniformly applied to the non-contact surface of the first dry roll of the film, preferably the entire surface.
  • Any of the sprayable methods can be adopted, and among them, the nozzle method, the straightening vane method, or a combination thereof and the like are preferably adopted.
  • the direction of blowing hot air onto the non-contact surface of the first dry roll of the film is substantially along the circumferential shape of the non-contact surface of the first dry roll of the film even in the direction facing the non-contact surface of the first dry roll. It may be in a direction (a direction substantially along the circumference of the roll surface of the first drying roll) or in any other direction.
  • the film when the film is dried on the first drying roll, it is preferable to exhaust the volatile matter generated from the film by drying and the hot air after blowing.
  • the exhaust method is not particularly limited, but it is preferable to adopt an exhaust method in which the wind speed unevenness and the temperature unevenness of the hot air blown on the non-contact surface of the first drying roll of the film do not occur.
  • the film-forming stock solution discharged in the form of a film on the first drying roll is dried on the first drying roll, and the obtained film is peeled off from the first drying roll. If the volatile fraction of the film at the time of peeling from the first drying roll is too low, the productivity of the PVA film tends to decrease. On the other hand, if the volatile fraction of the film at the time of peeling from the first dry roll is too high, peeling from the first dry roll tends to be difficult, and in some cases, breakage or spots are likely to occur. ..
  • the volatile content of the film at the time of peeling from the first dry roll is preferably 10% by mass or more, more preferably 15% by mass or more, and 18% by mass or more. Is more preferably 30% by mass or less, more preferably 29% by mass or less, further preferably 28% by mass or less, and particularly preferably 27% by mass or less.
  • the "volatile fraction of the film" in the present specification means the volatile fraction obtained by the following formula (II).
  • M (mass%) ⁇ (Wc-Wd) / Wc ⁇ x 100 (II) (Here, M is the volatile fraction (mass%) of the film, Wc is the mass (g) of the sample collected from the film, and Wd is the vacuum drying of the sample Wc (g) at a temperature of 50 ° C. and a pressure of 0.1 kPa or less. The mass (g) after being put in the machine and dried for 4 hours is shown.)
  • a film formed from a film-forming stock solution prepared using a polyhydric alcohol (plasticizer) such as PVA or glycerin, a surfactant, and water the above-mentioned "temperature 50 ° C., pressure 0.1 kPa or less for 4 hours".
  • a polyhydric alcohol such as PVA or glycerin
  • a surfactant such as water
  • water water
  • the volatile content of the film is the water content contained in the film. It can be obtained by measuring the amount (moisture content).
  • the film dried on the first drying roll is peeled off from the first drying roll, and then the non-contact surface of the first drying roll of the film is made to face the second drying roll, and the film is dried by the second drying roll. Further, if necessary, the film is dried with a drying roll after the third drying roll. At this time, it is preferable to dry the film by making the non-contact surface of the film in the immediately preceding drying roll face the drying roll to be contacted next.
  • FIG. 1 is a schematic view of an example of a different diameter drying roll 1 and a film 2 in contact with the different diameter drying roll 1.
  • the different diameter drying roll 1 is located at a position 3 (hatched portion in FIG. 1) of 50 mm or more and 250 mm or less from both ends of the film 2 in contact with the different diameter drying roll 1 toward the central portion in the width direction.
  • a drying roll in which the outer diameter t 1 of the different diameter drying roll 1 in at least a part of the region 4 is 1.0 mm to 3.0 mm larger than the outer diameter t 2 in the central portion in the width direction is used.
  • the drying roll a cylindrical drying roll (flat roll) having the same outer diameter at the central portion and the outer diameter at both ends is used.
  • the PVA film of the present invention can be smoothly produced by using the different diameter drying roll 1 as described above.
  • the present invention is not limited in any way, but the reason for this is that when the outer diameter t 1 of the deformed drying roll 1 is large from both ends of the film 2 in contact with the deformed drying roll 1 to the central portion in the width direction, the film. Both ends of 2 are lifted.
  • the width t 3 of the region 4 having a large outer diameter t 1 is preferably 10 to 55 mm. Within this range, the effect of the present invention is particularly high.
  • the preferred width t 3 of the region 4 having a large outer diameter t 1 is 10 to 40 mm.
  • the different diameter drying roll 1 is a metal roll having a uniform outer diameter, and is fluorine-based in at least a part of a region at a position of 50 mm or more and 250 mm or less from both ends of the PVA film in contact with the metal roll toward the center in the width direction. It is preferable that a region having a large outer diameter is provided by attaching a resin tape. Thus, it is preferable to provide an outer diameter t 1 is larger region 4 by affixing a fluorine resin tape in place of the metal roll. According to this method, the position of the outer diameter t 1 is larger region 4, the width, and the outer diameter t 1 can be easily adjusted.
  • the different diameter drying roll of the present invention is used for at least one of the drying rolls after the second drying roll.
  • only one of the second to final drying rolls may be the different diameter drying roll of the present invention, or two or more may be the different diameter drying roll of the present invention.
  • the second drying roll is preferably the different diameter drying roll of the present invention, and one or more of the second drying roll and the drying roll from the third drying roll to the final drying roll, a total of two or more, have different diameters of the present invention. More preferably, it is a dry roll. It is also preferable that all the drying rolls from the second drying roll to the final drying roll are the different diameter drying rolls of the present invention.
  • the shape of the first drying roll is preferably a normal cylindrical shape, that is, the outer diameter of the central portion and the outer diameter of both end portions are the same.
  • the film shrinks toward the center in the width direction as the drying progresses.
  • the position of the region where the outer diameter of the different diameter drying roll is large is defined by the distance from the edge of the film. Therefore, when a plurality of different diameter drying rolls of the present invention are used and the widths of all the different diameter drying rolls are the same, the position of the region having a large outer diameter with respect to the end of the different diameter drying roll is the film flow direction. It is preferable that the dry roll on the downstream side of the roll is closer to the center side in the width direction.
  • the surface temperature of the drying rolls after the second drying roll is preferably 50 to 100 ° C., more preferably 60 to 95 ° C. from the viewpoint of ensuring the transportability of the PVA film of the present invention during production and the rigidity of the product.
  • the drying rolls after the second drying roll only the final drying roll, or one or more drying rolls closer to the final drying roll than the first drying roll and the final drying roll have different surface temperatures. It may be higher than the roll and used as a heat treatment roll. That is, the drying roll in the above-mentioned film forming apparatus includes the heat treatment roll when the heat treatment roll is used.
  • the surface temperature of the dry roll is preferably 90 to 120 ° C, more preferably 100 to 110 ° C.
  • the peripheral speed (S1) of the first drying roll is preferably 5 to 30 m / min, more preferably 7 to 25 m / min, from the viewpoints of uniform drying property, drying rate, productivity of PVA film, and the like. preferable. If the peripheral speed (S1) of the first drying roll is less than 5 m / min, the productivity tends to decrease and the stretchability of the obtained PVA film tends to decrease. On the other hand, when the peripheral speed (S1) of the first drying roll exceeds 30 m / min, the peeling from the first drying roll tends to be non-uniform and defects tend to occur.
  • the ratio (ST / S1) of the peripheral speed (ST) of the final drying roll to the peripheral speed (S1) of the first drying roll is 0.960 to 1.100. Is preferable. If the ratio (ST / S1) is too low, the film tends to sag between the drying rolls, and if it is too high, the retardation tends to increase and the retardation spots in the width direction tend to increase. On the other hand, the ratio (ST / S1) is more preferably 1.050 or less, and further preferably 1.030 or less.
  • the film forming apparatus may have a hot air furnace type hot air drying apparatus, a heat treatment apparatus, a humidity control apparatus, and the like. For example, after drying with the drying roll (including heat treatment with the heat treatment roll), these may be provided. Humidity control treatment can be performed using the device of. Further, both ends (ears) of the film may be cut if necessary.
  • the volatile fraction (typically the water content) of the PVA film finally obtained by the above series of treatments is usually in the range of 1 to 5% by mass. If the volatile fraction is too high, the amount of dimensional change in water tends to be high.
  • the obtained PVA film is preferably wound into a roll with a predetermined length.
  • the PVA film further contains, for example, the above-mentioned amount of a plasticizer, a surfactant, and various other additives as described above as those used in the production method of the present invention. May be good.
  • the PVA film obtained by the production method of the present invention is suitably used as a raw material for optics, particularly for producing a polarizing film.
  • the thickness of the PVA film is not particularly limited, but is preferably 5 to 80 ⁇ m.
  • a PVA film having such a thickness is suitably used as a raw fabric or the like for producing a polarizing film.
  • a more suitable thickness is 20 to 80 ⁇ m.
  • the width of the PVA film is not particularly limited, but since liquid crystal televisions and monitors have become larger in recent years, the width is preferably 2 m or more and 3 m in order to be able to be effectively used for these purposes. It is more preferably 4 m or more, and further preferably 4 m or more. The wider the width of the PVA film, the more remarkable the effect of the present invention becomes, and it is preferable because a large-area polarizing film can be obtained. On the other hand, when manufacturing a polarizing plate with a realistic production machine, if the width of the film is too wide, uniform uniaxial stretching may be difficult, so the width of the PVA film is preferably 7.5 m or less. , 7 m or less is more preferable.
  • the length of the PVA film is not particularly limited, and can be, for example, 50 to 30,000 m.
  • the retardation value of the PVA film is not particularly limited, but it is preferably 40 nm or less from the viewpoint that the smaller the retardation value, the more the phase difference unevenness in the width direction of the obtained polarizing film tends to improve.
  • the PVA film may be dyed, uniaxially stretched, fixed, dried, and heat-treated if necessary.
  • the order of dyeing and uniaxial stretching is not particularly limited, and the dyeing treatment may be performed before the uniaxial stretching treatment, the dyeing treatment may be performed at the same time as the uniaxial stretching treatment, or the dyeing treatment may be performed after the uniaxial stretching treatment. You may go. Further, steps such as uniaxial stretching and dyeing may be repeated a plurality of times. In particular, it is preferable to divide the uniaxial stretching into two or more stages because uniform stretching can be easily performed.
  • Dyes used for dyeing PVA films include iodine or dichroic organic dyes (eg, DirectBlack 17, 19, 154; DirectBrown 44, 106, 195, 210, 223; DirectRed 2, 23, 28, 31, 37, 39; , 79, 81, 240, 242, 247; DirectBlue 1, 15, 22, 78, 90, 98, 151, 168, 202, 236, 249, 270; Direct Violet 9, 12, 51, 98; Direct Green 1, 85; Direct Yellow 8, 12, 44, 86, 87; dichroic dyes such as Direct Orange 26, 39, 106, 107) and the like can be used. These dyes can be used alone or in combination of two or more. Dyeing can usually be performed by immersing the PVA film in a solution containing the above dye, but the treatment conditions and treatment method are not particularly limited.
  • the uniaxial stretching method for stretching the PVA film in the length direction (MD) or the like may be performed by either a wet stretching method or a dry heat stretching method, but from the viewpoint of the performance and quality stability of the obtained polarizing film, the wet stretching method is used.
  • the method is preferred.
  • the wet stretching method include a method of stretching a PVA film in an aqueous solution containing various components such as pure water, additives and an aqueous medium, or an aqueous dispersion in which various components are dispersed, and uniaxial stretching by the wet stretching method.
  • the method include a method of uniaxial stretching in warm water containing boric acid, a method of uniaxial stretching in a solution containing the above-mentioned dye, and a method of uniaxial stretching in a fixing treatment bath described later.
  • the PVA film after water absorption may be used for uniaxial stretching in the air, or uniaxial stretching may be performed by other methods.
  • the stretching temperature during uniaxial stretching is not particularly limited, but in the case of wet stretching, a temperature in the range of preferably 20 to 90 ° C, more preferably 25 to 70 ° C, still more preferably 30 to 65 ° C is adopted, and drying is performed. In the case of heat stretching, a temperature in the range of 50 to 180 ° C. is preferably adopted.
  • the stretch ratio of the uniaxial stretching treatment (the total stretching ratio in the case of uniaxial stretching in multiple stages) is preferably stretched as much as possible until just before the film is cut from the viewpoint of polarization performance, and specifically, it should be 4 times or more. Is preferable, 5 times or more is more preferable, and 5.5 times or more is further preferable.
  • the upper limit of the draw ratio is not particularly limited as long as the film is not broken, but it is preferably 8.0 times or less in order to perform uniform stretching.
  • fixing treatment is often performed in order to strengthen the adsorption of dyes on the uniaxially stretched film.
  • a method of immersing the film in a treatment bath to which a boric acid and / or a boron compound is added is generally widely adopted. At that time, an iodine compound may be added to the treatment bath if necessary.
  • the film subjected to the uniaxial stretching treatment or the uniaxial stretching treatment and the fixing treatment is then dried (heat treated).
  • the temperature of the drying treatment (heat treatment) is preferably 30 to 150 ° C., particularly preferably 50 to 140 ° C. If the temperature of the drying treatment (heat treatment) is too low, the dimensional stability of the obtained polarizing film tends to decrease, while if it is too high, the polarization performance tends to decrease due to decomposition of the dye or the like.
  • a protective film that is optically transparent and has mechanical strength can be attached to both sides or one side of the polarizing film obtained as described above to form a polarizing plate.
  • a cellulose triacetate (TAC) film, a cellulose acetate / butyrate (CAB) film, an acrylic film, a polyester film, or the like is used.
  • a PVA-based adhesive, a urethane-based adhesive, or the like is generally used, and among them, the PVA-based adhesive is preferably used.
  • the polarizing plate obtained as described above can be used as a component of a liquid crystal display device by coating it with an adhesive such as an acrylic material and then attaching it to a glass substrate.
  • an adhesive such as an acrylic material
  • a retardation film, a viewing angle improving film, a brightness improving film, or the like may be attached at the same time.
  • the present invention will be specifically described with reference to Examples, but the present invention is not limited to the following Examples.
  • the product effective width of the PVA film was measured or evaluated by the following method.
  • the effective width of the product is the width of the part excluding the traces of the fluororesin tape existing at both ends of the PVA film, the adhesion traces generated by the adhesion, and the parts where defects such as polarization spots are generated. did. When the effective width of the product was 80% or more of the casting width of the film-forming stock solution of the PVA-based polymer film on the drying roll, it was accepted.
  • Example 1 It consists of 100 parts by mass of PVA (saponification degree 99.9 mol%, average degree of polymerization 2400) obtained by saponification of polyvinyl acetate, 10.5 parts by mass of glycerin, 0.04 parts by mass of diethanolamide laurate and water. A film-forming stock solution having a volatile content of 67% by mass was prepared. Next, from the T-die (cast width 6380 mm), the first drying roll of the film forming apparatus (surface temperature 93 ° C., peripheral speed (S1)) 14. The film-forming stock solution is discharged in the form of a film on 5 m / min), and the volatile fraction is blown on the first drying roll with hot air at 90 ° C.
  • PVA ponification degree 99.9 mol%, average degree of polymerization 2400
  • the film obtained from the first drying roll is peeled off so that the front and back surfaces of any portion of the film alternately contact each drying roll after the second drying roll.
  • the drying was carried out with a drying roll.
  • the fluororesin is located at a position (the distance from the roll end to the tape end is shown in Table 1) on the width direction center side of both ends of the dry roll (metal roll) having a constant outer diameter in the width direction.
  • a tape width 40 mm
  • the position where the tape was applied was adjusted for each different diameter drying roll so that the distance from the end of the film to the end of the roll of the tape was 85 mm.
  • the outer diameter of the drying roll was 2.52 mm larger than that at the position where the tape was not applied.
  • Example 2 In Example 1, the cast width (4900 mm) of the T-die and the number of drying rolls were set to 24, and the drying rolls to which the fluorine-based resin tape was attached were set to 16 from the second drying roll to the 17th drying roll. The width and sticking position of the tape were changed as shown in Table 2 below, the surface temperature of the 2nd to 19th and 22nd to 23rd drying rolls was set to 75 to 95 ° C., and the 20th drying roll and the 21st drying roll were set to 75 to 95 ° C. Example 1 except that the surface temperature was set to 105 ° C.
  • Example 1 Comparative Example 1 In Example 1, a PVA film was obtained in the same manner except that the fluororesin tape was not attached to the drying roll. Since the effective product width of this PVA film is 4720 mm, which is 74% of the cast width, it was judged to be unacceptable.
  • the PVA film manufacturing method of the present invention it was possible to manufacture a PVA film having a wide product effective width.
  • the PVA film is particularly useful as a raw film for producing a large-area polarizing film.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Health & Medical Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Ophthalmology & Optometry (AREA)
  • Moulding By Coating Moulds (AREA)
  • Polarising Elements (AREA)
  • Manufacture Of Macromolecular Shaped Articles (AREA)
PCT/JP2020/045996 2019-12-11 2020-12-10 光学用ポリビニルアルコールフィルムの製造方法 WO2021117801A1 (ja)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012114820A1 (ja) * 2011-02-21 2012-08-30 コニカミノルタオプト株式会社 フィルムの製造方法、およびフィルムの製造装置
WO2012127893A1 (ja) * 2011-03-24 2012-09-27 コニカミノルタアドバンストレイヤー株式会社 光学フィルムの製造方法
WO2014208537A1 (ja) * 2013-06-28 2014-12-31 株式会社クラレ ポリビニルアルコール系重合体フィルムおよびその製造方法
JP2017101216A (ja) * 2015-11-25 2017-06-08 日本合成化学工業株式会社 ポリビニルアルコール系フィルムの製造方法、およびポリビニルアルコール系フィルム

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005279341A (ja) * 2004-03-26 2005-10-13 Fuji Photo Film Co Ltd 支持体の搬送方法、塗布装置、及び光学フィルム
JP5904725B2 (ja) * 2010-07-21 2016-04-20 日本合成化学工業株式会社 ポリビニルアルコール系フィルムの製造方法、ポリビニルアルコール系フィルム、偏光フィルム及び偏光板
JP2013091195A (ja) * 2011-10-25 2013-05-16 Konica Minolta Advanced Layers Inc 光学フィルムの製造方法及びそれにより製造された光学フィルム
WO2013146146A1 (ja) 2012-03-30 2013-10-03 株式会社クラレ ポリビニルアルコール系重合体フィルムおよび偏光フィルム
KR102387497B1 (ko) * 2014-12-12 2022-04-15 주식회사 쿠라레 폴리비닐알코올 필름
TWI721171B (zh) * 2016-05-27 2021-03-11 日商三菱化學股份有限公司 聚乙烯醇系薄膜、與利用該聚乙烯醇系薄膜的偏光膜

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012114820A1 (ja) * 2011-02-21 2012-08-30 コニカミノルタオプト株式会社 フィルムの製造方法、およびフィルムの製造装置
WO2012127893A1 (ja) * 2011-03-24 2012-09-27 コニカミノルタアドバンストレイヤー株式会社 光学フィルムの製造方法
WO2014208537A1 (ja) * 2013-06-28 2014-12-31 株式会社クラレ ポリビニルアルコール系重合体フィルムおよびその製造方法
JP2017101216A (ja) * 2015-11-25 2017-06-08 日本合成化学工業株式会社 ポリビニルアルコール系フィルムの製造方法、およびポリビニルアルコール系フィルム

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