WO2019054487A1 - Polyvinyl alcohol film and method for manufacturing same - Google Patents
Polyvinyl alcohol film and method for manufacturing same Download PDFInfo
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- WO2019054487A1 WO2019054487A1 PCT/JP2018/034204 JP2018034204W WO2019054487A1 WO 2019054487 A1 WO2019054487 A1 WO 2019054487A1 JP 2018034204 W JP2018034204 W JP 2018034204W WO 2019054487 A1 WO2019054487 A1 WO 2019054487A1
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- 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
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
- C08J5/18—Manufacture of films or sheets
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/30—Polarising elements
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2329/00—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal, or ketal radical; Hydrolysed polymers of esters of unsaturated alcohols with saturated carboxylic acids; Derivatives of such polymer
- C08J2329/02—Homopolymers or copolymers of unsaturated alcohols
- C08J2329/04—Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids
Definitions
- the present invention relates to a polyvinyl alcohol film (hereinafter sometimes referred to as “polyvinyl alcohol” may be abbreviated as "PVA”) and a method for producing the same.
- PVA polyvinyl alcohol film
- a polarizing plate having a light transmission and shielding function is an important component of a liquid crystal display (LCD).
- LCD liquid crystal display
- Liquid crystal display devices are used in a wide range of fields such as notebook computers, liquid crystal monitors, liquid crystal color projectors, liquid crystal televisions, car navigation systems, mobile phones, measuring instruments used indoors and outdoors.
- the polarizing plate is usually produced by coloring a PVA film unwound from a roll and uniaxially stretching it, and then preparing a polarizing film by a fixation treatment with a boron compound, etc. It is manufactured industrially by bonding together protective films, such as a cellulose acetate film and a acetic acid * cellulose butyrate film.
- Patent Document 1 describes a method for producing a PVA film, which uses (a) a film forming apparatus provided with a plurality of drying rolls whose rotating shafts are parallel to each other, and uses PVA on the first drying roll of the film forming apparatus.
- the film-forming stock solution is discharged and partially dried, and then further dried with a subsequent drying roll to form a film; and in that case, (b) the circumferential speed of the final drying roll relative to the peripheral speed (S 1 ) of the first drying roll.
- Patent Document 2 describes a method for producing a PVA film, which uses (a) a film forming apparatus provided with three or more drying rolls whose rotation axes are parallel to each other, and which is positioned most upstream among the drying rolls. (1) After the film-forming stock solution containing PVA is discharged onto the drying roll and partially dried, it is further dried by the subsequent drying roll to form a film; in that case, (b) PVA when peeled off from the first drying roll The volatile fraction of the film is set to 20 to 40% by mass; (c) the ratio (S 2 / S 1 ) of the peripheral speed (S 2 ) of the second drying roll to the peripheral speed (S 1 ) of the first drying roll is 1 (D) Of the second drying roll or the downstream drying roll, the drying roll (the xth drying roll) and the PVA film when the volatilization of the PVA film reaches 20% by mass.
- a film forming apparatus provided with three or more drying rolls whose rotation axes are parallel to each other, and which is positioned most
- the present invention has been made to solve the above problems, and provides a thin and wide PVA film having excellent stretchability and having a small variation in width after stretching, and a simple process for producing the same. With the goal.
- the subject is a PVA film with a width of 3 m or more, a length of 1,000 m or more, and a thickness of 15 to 65 ⁇ m, and the retardation value measured with the pitch in the length direction of 15 m and the pitch in the width direction of 10 mm
- the problem is solved by providing a PVA film characterized by satisfying (1) to (4).
- Re i (nm): Retardation value Re total (nm) of measurement point i (i 1 to n, n is an integer) at a position of 10 mm from the end: Average value of retardation of all measurement points.
- the said subject is a manufacturing method of the said PVA film, Comprising:
- the film forming apparatus provided with the several drying roll in which a rotating shaft is mutually parallel is used,
- the said several drying roll is the mth drying roll from the 1st drying roll ( m represents an integer of 3 or more, and after a film is prepared by discharging a film-forming stock solution containing PVA from the die onto the first drying roll and obtaining a film, the second to m-th drying rolls are used.
- the volatile fraction of the membrane-forming stock solution containing PVA is 60 to 75% by mass, and the peripheral speed (S 1 ) of the first drying roll is 8 to 25 m / min.
- the PVA film of the present invention has excellent stretchability even if it is thin and wide, and in addition, the variation in width after stretching is small. According to the production method of the present invention, such a PVA film can be produced conveniently. By using such a PVA film, a thin and wide optical film or the like excellent in optical performance can be produced with high productivity.
- the PVA film of the present invention has a width of 3 m or more, a length of 1,000 m or more, a thickness of 15 to 65 ⁇ m, and the retardation value measured with the pitch in the length direction of 15 m and the pitch in the width direction of 10 mm (1) to (4) are satisfied.
- Re i (nm): Retardation value Re total (nm) of measurement point i (i 1 to n, n is an integer) at a position of 10 mm from the end: average value of retardation of all measurement points, It is.
- the retardation Re (nm) of the film is represented by the following formula.
- the retardation is measured at 15 m pitch 5 in the lengthwise direction 4 of the PVA film 1 at positions of 10 mm from both ends 2 and 3 of the PVA film 1 respectively.
- the maximum value of retardation in all measurement points i at positions of 10 mm from both ends 2 and 3 of PVA film 1 is Re max , the minimum value is Re min , and the number average value is Re ave .
- Re max The maximum value of retardation in all measurement points i at positions of 10 mm from both ends 2 and 3 of PVA film 1
- Re min the minimum value
- Re ave the number average value
- the retardation of the entire PVA film 1 is measured in order to obtain Re total in the formula (3).
- measurement is performed so that positions of 10 mm are included from both ends 2 and 3 of the PVA film 1 respectively.
- Re i , Re max , Re min and Re ave are also determined along with Re total using the measurement value at this time.
- Both A in the above-mentioned formula (1) and B in the above-mentioned formula (2) become an index of spots of retardation in the lengthwise direction of the PVA film of the present invention.
- the PVA film of the present invention which satisfies the above formulas (1) and (2) and has a small unevenness of retardation in the lengthwise direction is excellent in stretchability and also has a small fluctuation in width after stretching.
- An optical film produced by stretching the PVA film has excellent optical performance.
- a in the above formula (1) exceeds 10 nm, the optical performance of the obtained optical film becomes insufficient.
- the stretchability and the uniformity of the film width after stretching are also reduced.
- As for A 9.5 nm or less is preferable.
- B in the above formula (2) exceeds 1.5 nm, the optical performance of the obtained optical film becomes insufficient. In addition, the stretchability and the uniformity of the film width after stretching are also reduced.
- B is preferably 1.2 nm or less. On the other hand, B is usually 0.1 nm or more.
- the Re total (nm) in the above equation (3) is the number of retardations at all measurement points when the retardation is measured for the entire PVA film with a pitch in the length direction of 15 m and a pitch in the width direction of 10 mm. It is an average value.
- the stretchability of the PVA film is improved by setting Re total in the range represented by the above formula (3).
- Re total is preferably 18 nm or less.
- the measurement is performed so that positions of 10 mm from each of the two ends 2 and 3 of the PVA film 1 are included.
- Re i , Re max , Re min and Re ave are also determined along with Re total using the measured value at this time.
- the formula (4) is obtained by defining the ratio of A (A / Re total) for Re total.
- A is the difference between the maximum value Re max and the minimum value Re min of retardation at a position of 10 mm from the end of the PVA film, and the smaller the difference, the better the optical properties of the obtained optical film, which seems to be preferable Be
- the present inventors have conducted extensive studies to improve the optical performance of the optical film obtained with stretching of the PVA film, surprisingly, the ratio of A to Re total of (A / Re total) By making it 0.3 or more, it has been found that the stretchability is significantly improved with almost no decrease in optical performance.
- the ratio (A / Re total ) is more preferably 0.4 or more.
- the ratio (A / Re total ) is preferably 2 or less, more preferably 1 or less.
- the thickness of the PVA film of the present invention is 15 to 65 ⁇ m, and the width is 3 m or more.
- the PVA film of the present invention satisfying the above formulas (1) to (4) has excellent stretchability even if it is thin and wide as described above, and the variation in width after stretching is small. By using such a PVA film, a thin and wide optical film excellent in optical performance can be produced with high productivity.
- the thickness of the PVA film is preferably 20 ⁇ m or more.
- the width of the PVA film is preferably 3.5 m or more.
- the uniform uniaxial stretching may become difficult if the width of the film is too wide, so the width of the PVA film is 8 m or less Is preferred.
- the length of the PVA film of the present invention is 1,000 m or more.
- the PVA film of the present invention is excellent in stretchability. Therefore, an optical film can be stably manufactured for a long time by using the said PVA film as a raw material of an optical film.
- the length of the PVA film is preferably 50,000 m or less, and more preferably 20,000 m or less.
- PVA used for the film of this invention what was manufactured by saponifying the polyvinyl ester obtained by polymerizing a vinyl ester can be used.
- the vinyl ester include vinyl formate, vinyl acetate, vinyl propionate, vinyl valerate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl pivalate, and vinyl versatate.
- vinyl esters vinyl acetate is preferable from the viewpoint of availability, cost, easiness of production of PVA, and the like.
- the polyvinyl ester described above is preferably obtained using only one or two or more vinyl esters as a monomer, and more preferably obtained using only one vinyl ester as a monomer However, it may be a copolymer of one or more vinyl esters with other monomers copolymerizable therewith.
- vinyl esters for example, ethylene; olefins having 3 to 30 carbon atoms such as propylene, 1-butene, isobutene ( ⁇ -olefin etc.), acrylic acid or a salt thereof Methyl acrylate, ethyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, i-butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate Acrylic acid esters such as octadecyl acrylate; methacrylic acid or salts thereof; methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, methacrylic acid t-
- the proportion of the structural unit derived from the other monomer in the polyvinyl ester is preferably 15 mol% or less, and 5 mol% or less, based on the number of moles of all structural units constituting the polyvinyl ester. It is more preferable that
- the above PVA may be one modified by one or more graft copolymerizable monomers.
- the graft copolymerizable monomers include unsaturated carboxylic acids or derivatives thereof; unsaturated sulfonic acids or derivatives thereof; and ⁇ -olefins having 2 to 30 carbon atoms.
- the proportion of structural units derived from graft copolymerizable monomers in PVA is preferably 5 mol% or less based on the number of moles of all structural units constituting PVA.
- a part of the hydroxyl groups may or may not be crosslinked.
- a part of the hydroxyl groups may be reacted with an aldehyde compound such as acetaldehyde or butyraldehyde to form an acetal structure, or not reacted with these compounds to form an acetal structure May be
- the polymerization degree of PVA is not particularly limited, but is preferably 500 or more, more preferably 1,000 or more, and preferably 1,500 or more from the viewpoint of film strength and durability of the obtained optical film. Is more preferable, and 2,000 or more is particularly preferable. On the other hand, when the degree of polymerization is too high, the polymerization degree of PVA is preferably 10,000 or less, since it tends to lead to an increase in production cost and poor processability during film formation. Some are more preferable, 8,000 or less is more preferable, and 7,000 or less is particularly preferable.
- the degree of polymerization of PVA referred to in the present specification means an average degree of polymerization measured in accordance with the description of JIS K 6726-1994.
- the degree of saponification of PVA is not particularly limited, the degree of saponification of PVA is preferably 95% by mole or more, and preferably 98% by mole or more, from the viewpoint of optical performance and durability of the optical film produced from the obtained PVA film. Is more preferably 99% by mol or more, and particularly preferably 99.2% by mol or more.
- the degree of saponification of PVA in the present specification refers to the total number of moles of structural units (typically, vinyl ester units) that can be converted into vinyl alcohol units by saponification and the vinyl alcohol units, which PVA has. It refers to the proportion (mol%) of the number of moles of vinyl alcohol units.
- the degree of saponification of PVA can be measured according to the description of JIS K6726-1994.
- the PVA film of the present invention As a raw material of the PVA film of the present invention, one type of PVA may be used alone, or two or more types of PVA having different types of modification, modification rate, degree of polymerization, degree of saponification, etc. may be used in combination.
- the PVA film when secondary processing is required for the PVA film of the present invention, such as when used as a raw fabric for producing an optical film, the PVA film has an acidic functional group such as a carboxyl group or a sulfonic acid group.
- the PVA film does not contain any of PVA having an acidic functional group, PVA having an acid anhydride group, PVA having a basic functional group and a neutralized product thereof.
- PVA PVA produced by saponifying polyvinyl ester obtained by using only vinyl ester as a monomer, and / or only vinyl ester and ethylene and / or only olefin having 3 to 30 carbon atoms It is more preferable to contain only PVA produced by saponifying polyvinyl ester obtained by using it for the body, and produced by saponifying polyvinyl ester obtained using only vinyl ester as a monomer as PVA. It is further preferable to contain only the PVA obtained by saponifying the obtained PVA and / or the polyvinyl ester obtained by using only the vinyl ester and ethylene as monomers.
- the PVA film is produced using the PVA thus obtained.
- the manufacturing method of the PVA film of the present invention is not particularly limited, a film forming apparatus provided with a plurality of drying rolls whose rotation axes are parallel to each other is used, and the plurality of drying rolls are mth drying roll (m to m) Is an integer of 3 or more), and a film forming solution containing polyvinyl alcohol is discharged from the die onto the first drying roll and dried to obtain a film, and then the second to m-th drying rolls are produced.
- the ratio (S 2 / S 1) is 1.015 to 1.050 of the peripheral speed of the roll (S 2), the peripheral speed of the second drying roll against (S 2), the volatile fraction of the film is 11 mass %less than
- the ratio (S x / S 2 ) of the peripheral speed (S x ) of the drying roll (the x-th drying roll) which contacts for the first time is 0.970 to 0.995, and the second drying roll to the x-th drying roll It is preferred to produce by the process, the average of the roll temperature up to 63-81.degree.
- a solution obtained by mixing PVA with a liquid medium or a melt obtained by melting a PVA chip containing a liquid medium or the like is used. These can be prepared using a stirring mixer, a melt extruder, and the like.
- the liquid medium used at that time include water, dimethylsulfoxide, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, ethylenediamine, diethylenetriamine and the like.
- One of these liquid media may be used alone, or two or more thereof may be used in combination.
- water, dimethyl sulfoxide, or a mixture thereof is preferably used, and water is more preferably used.
- the film-forming solution preferably contains a plasticizer, from the viewpoint of further improving the stretchability of the obtained PVA film.
- a plasticizer polyhydric alcohols are preferably used and, for example, ethylene glycol, glycerin, diglycerin, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, trimethylolpropane and the like can be mentioned.
- the plasticizer may be used alone or in combination of two or more. Among them, one or more of glycerin, diglycerin and ethylene glycol are preferably used.
- the content of the plasticizer is preferably 0.1 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 content of the plasticizer is 30 parts by mass or less with respect to 100 parts by mass of PVA, the handleability of the obtained PVA film is improved.
- the film-forming solution preferably contains a surfactant from the viewpoint of improving the releasability from the drying roll when producing a PVA film, and the handleability of the obtained PVA film.
- a PVA film containing a surfactant can be obtained by using a film-forming solution containing a surfactant.
- the type of surfactant is not particularly limited, but anionic surfactants or nonionic surfactants are preferably used. These surfactants may be used alone or in combination of two or more.
- anionic surfactant for example, carboxylic acid type such as potassium laurate, sulfuric acid ester type such as octyl sulfate, and sulfonic acid type anionic surfactant such as dodecylbenzene sulfonate are preferable.
- nonionic surfactant for example, alkyl ether type such as polyoxyethylene oleyl ether, alkyl phenyl ether type such as polyoxyethylene octyl phenyl ether, alkyl ester type such as polyoxyethylene laurate, polyoxyethylene Alkyl amine type such as lauryl amino ether, alkyl amide type such as polyoxyethylene lauric acid amide, polypropylene glycol ether type such as polyoxyethylene polyoxypropylene ether, alkanolamide type such as lauric acid diethanolamide, oleic acid diethanolamide, Allylphenyl ether nonionic surfactants such as polyoxyalkylene allyl phenyl ether are preferred.
- alkyl ether type such as polyoxyethylene oleyl ether
- alkyl phenyl ether type such as polyoxyethylene octyl phenyl ether
- alkyl ester type such as polyoxyethylene laurate
- the content of the surfactant is preferably 0.01 to 1 part by mass, more preferably 0.02 to 0.5 parts by mass, and more preferably 0.05 to 0.3 based on 100 parts by mass of PVA. More preferably, it is part by weight.
- the content of the surfactant is 0.01 parts by mass or more with respect to 100 parts by mass of PVA, the stretchability and the dyeability are further improved.
- the handleability of a PVA film improves because content of surfactant is 1 mass part or less with respect to 100 mass parts of PVA.
- the membrane forming solution is a stabilizer (antioxidant, ultraviolet absorber, heat stabilizer etc.), compatibilizer, antiblocking agent, flame retardant, antistatic agent, lubricant, dispersant, fluidizer, antibacterial agent, etc. And various additives may be included. These additives may be used alone or in combination of two or more.
- the volatile fraction of the membrane-forming stock solution used for producing a PVA film is 60 to 75% by mass.
- the film-forming stock solution having a volatilization fraction of 60% by mass or more has an appropriate viscosity, so the film-forming property is improved. More preferably, the volatile fraction is 65% by mass or more.
- the uniformity of the thickness of the PVA film obtained improves because a volatile matter fraction is 75 mass% or less.
- the volatile fraction of the membrane-forming solution is determined by the following formula (i).
- Volatile fraction (mass%) ⁇ (Wa ⁇ Wb) / Wa ⁇ ⁇ 100 (i) [Wherein, Wa represents the mass (g) of the membrane-forming solution, Wb represents the mass (g) of the component remaining after drying the membrane-forming solution of Wa (g) in the electrothermal dryer at 105 ° C. for 16 hours. ]
- the surface of the drying roll is resistant to corrosion and preferably has a mirror gloss.
- the drying roll is preferably formed of a metal such as nickel, chromium, copper, iron, stainless steel or the like.
- a plated layer of nickel, chromium, nickel / chromium alloy or the like is formed in a single layer or a multilayer on the surface of the drying roll.
- the film forming apparatus used in the present invention may have a hot-air oven type hot-air drying apparatus, a heat treatment apparatus, a humidity control apparatus, and the like following the drying roll, as necessary.
- the number of drying rolls in the film forming apparatus is 3 or more, preferably 5 to 30.
- the film forming apparatus has a known discharge device (casting device) such as a T-shaped slit die, a hopper plate, an I-die, and a lip coater die.
- the film forming solution is discharged (casted) into a film form from the die of the apparatus onto the first drying roll.
- the film After a film is obtained by drying the film-forming stock solution discharged onto the first drying roll on the first drying roll, the film is peeled off from the first drying roll.
- the volatile fraction of the film at the time of peeling from the first drying roll needs to be 12 to 20% by mass.
- the volatile fraction of the film when peeled off the first drying roll is less than 12% by mass, the stretchability is significantly reduced.
- the volatilization fraction of the film at the time of peeling from the first drying roll exceeds 20% by mass, the peelability of the film from the first drying roll is deteriorated, and thickness unevenness in the flow direction becomes large.
- the volatile fraction is preferably 19% by mass or less, more preferably 18% by mass or less, and still more preferably 16% by mass or less.
- the volatile fraction of the film is determined by the following formula (ii) after collecting the film immediately after peeling from the first drying roll.
- Volatile fraction (mass%) ⁇ (Wc ⁇ Wd) / Wc ⁇ ⁇ 100 (ii) [Wherein, Wc represents the mass (g) of the collected film, and Wd represents the mass (g) of the film after the film Wc (g) was dried in a dryer at a temperature of 105 ° C. for 16 hours. ]
- the surface temperature of the first drying roll is preferably 80 to 120 ° C. in terms of the uniformity of drying, the drying speed and the like. If the surface temperature is less than 80 ° C., drying on the first drying roll tends to be insufficient, which tends to cause peeling failure.
- the surface temperature is more preferably 85 ° C. or more. On the other hand, when the surface temperature exceeds 120 ° C., the film tends to foam easily.
- the surface temperature is more preferably 105 ° C. or less, and still more preferably 99 ° C. or less.
- the circumferential speed (S 1 ) of the first drying roll is preferably 8 to 25 m / min from the viewpoint of the uniformity of drying, the drying speed, the productivity, and the like. If the circumferential speed (S 1 ) is less than 8 m / min, the productivity may be reduced.
- the circumferential speed (S 1 ) is more preferably 10 m / min or more, further preferably 12 m / min or more.
- the circumferential speed (S 1 ) exceeds 25 m / min, the drying on the first drying roll tends to be insufficient. Moreover, it is more preferable that it is 23 m / min or less, and it is still more preferable that it is 22 m / min or less.
- the film-forming stock solution discharged onto the first drying roll may be dried using only the first drying roll, by blowing hot air onto the film surface not in contact with the first drying roll. And heat may be applied from both sides of the film for drying. This further improves the uniformity of drying and the drying speed.
- the velocity of the hot air is preferably 1 to 10 m / sec, more preferably 2 to 8 m / sec, and still more preferably 3 to 8 m / sec.
- the temperature of the hot air is preferably 50 to 150 ° C., more preferably 70 to 120 ° C., and still more preferably 80 to 95 ° C. from the viewpoint of drying efficiency, uniformity of drying, and the like. Further, the dew point temperature of the hot air is preferably 10 to 15 ° C. When the temperature of the hot air is too low, the drying efficiency, the uniformity of drying, and the like are likely to be reduced. On the other hand, when the temperature of the hot air is too high, foaming tends to occur.
- the film dried to a volatile content of 12 to 20% by mass by the first drying roll is peeled off from the roll, and the film is further dried by the second drying roll.
- the ratio (S 2 / S 1 ) of the peripheral speed (S 2 ) of the second drying roll to the peripheral speed (S 1 ) of the first drying roll is preferably 1.015 to 1.050. If the ratio (S 2 / S 1) is less than 1.015, the film from the first drying roll is difficult peeling, the uniformity of the width direction of the obtained PVA film may be lowered. On the other hand, when the ratio (S 2 / S 1 ) exceeds 1.050, tension unevenness applied to the film between the first drying roll and the second drying roll becomes large, and the uniformity of the obtained PVA film is increased. There is a risk of loss of
- the ratio (S a + 1 / S) of the peripheral speed (S a + 1 ) of the downstream drying roll to the peripheral speed (S a ) of the upstream drying roll of the two adjacent drying rolls a ) is preferably 0.975 to 1.
- the ratio (S a + 1 / S a ) in all two adjacent drying rolls is 0.975 to 1.
- the average of the roll temperature of the second drying roll to the xth drying roll is 63 to 81.degree.
- the optical performance of the obtained optical film may be insufficient when A and B exceed the upper limit.
- the stretchability of the PVA film and the uniformity of the film width after stretching may also be reduced.
- all the roll temperatures of the second drying roll to the x-th drying roll be 50 to 95.degree.
- the roll temperature is less than 50 ° C. or more than 95 ° C.
- the optical performance of the obtained optical film may be insufficient when A and B exceed the respective upper limits.
- the stretchability and the uniformity of the film width may be reduced.
- a further drying roll is disposed downstream of the x-th drying roll, downstream of the peripheral speed (S b ) of the drying roll upstream of the two adjacent drying rolls in the x-th drying roll to the m-th drying roll
- the ratio (S b + 1 / S b ) of the peripheral speed (S b + 1 ) of the drying roll is preferably 0.975 to 1. It is preferable that the roll temperatures of the (x + 1) th to the (m) th drying rolls are all 50 to 130 ° C.
- the surface temperature of at least a part of the drying rolls may be increased. Thereby, drying and heat treatment of a PVA film can be performed simultaneously.
- the roll temperature at this time is preferably 90 to 140 ° C., and more preferably 95 to 130 ° C.
- the ratio (S m / S 1 ) of the peripheral speed (S m ) of the mth drying roll to the peripheral speed (S 1 ) of the first drying roll is not particularly limited, but is in the range of 0.900 to 1.100 Are more preferably in the range of 0.950 to 1.050, still more preferably in the range of 0.980 to 1.020, and in the range of 0.990 to 1.010. Is particularly preferred.
- the ratio (W T / W 1 ) of the film width (W T ) after both ends (ears) are cut to the film width (W 1 ) when discharged from the die is 0.6 or more It is preferably present, and more preferably 0.7 or more.
- the edge part of the PVA film formed into a film by the conventional method had a high retardation value, and such a PVA film had inadequate ductility.
- the stretchability is improved by cutting the end of the PVA film wider, the width of the obtained PVA film is narrowed, and the cost is also increased due to an increase in the discarded portion, which causes a problem. It had become.
- the manufacturing method of the present invention since the retardation value of the PVA film end after film formation can be reduced, there is no need to cut the end widely, and a wide PVA film excellent in stretchability Is obtained.
- the dried PVA film may be subjected to a humidity control process, etc., as required, and may be wound into a roll.
- the volatile fraction of the PVA film finally obtained is preferably 1 to 5% by mass, and more preferably 2 to 4% by mass. Moreover, it is preferable that it is 50 mass% or more, and, as for content of PVA in the said PVA film, it is more preferable that it is 80 mass% or more.
- the PVA film of the present invention has excellent stretchability even if it is thin and wide, and the variation in width after stretching is small.
- a thin and wide optical film excellent in optical performance, particularly a polarizing film can be produced with high productivity.
- the screen size of liquid crystal televisions and monitors has been increasing.
- weight reduction of notebook computers, mobile phones, etc. is also in progress.
- the PVA film of the present invention is suitably used as a raw material of an optical film used for these.
- the said optical film can be manufactured by the manufacturing method which has the process of uniaxially stretching using the PVA film of this invention.
- Examples of a method of producing a polarizing film using the PVA film of the present invention as a raw fabric include a method of dyeing, uniaxial stretching, fixing treatment, drying treatment, and heat treatment if necessary, using the PVA film of the present invention.
- the order of dyeing and uniaxial stretching is not particularly limited, and dyeing may be performed before uniaxial stretching, may be performed simultaneously with uniaxial stretching, or may be performed after uniaxial stretching. In addition, the steps such as uniaxial stretching and dyeing may be repeated multiple times.
- dyes used for dyeing of PVA film iodine or dichroic organic dyes (for example, DirectBlack 17, 19, 154; Direct Brown 44, 106, 195, 210, 223; Direct Red 2, 23, 28, 31, 37, 39 79, 81, 240, 242, 247; DirectBlue 1, 15, 22, 78, 90, 98, 151, 168, 236, 249, 270; Direct Violet 9, 12, 51, 98; DirectGreen 1, 85; DirectYellow 8, 12, 44, 86, 87; dichroic dyes such as DirectOrange 26, 39, 106, 107, etc. can be used. These dyes may be used alone or in combination of two or more. Dyeing can be usually carried out 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 of the PVA film may be performed by either a wet stretching method or a dry heat stretching method.
- uniaxial stretching may be performed in warm water containing boric acid, uniaxial stretching may be performed in a solution containing the above-described dye or in a fixing treatment bath described later, or after water absorption
- the film may be uniaxially stretched in air using a PVA film of or any other method.
- the stretching temperature in uniaxial stretching is not particularly limited, but preferably 30 to 90 ° C., more preferably 40 to 70 ° C., still more preferably 45 to 65 ° C.
- the stretching ratio of uniaxial stretching is specifically 4 times or more Is preferably 5 times or more, more preferably 5.5 times or more.
- the upper limit of the draw ratio is not particularly limited as long as the film does not break, but in order to perform uniform drawing, it is preferably 8.0 times or less.
- the draw ratio in this specification is based on the length of the film before extending
- the thickness of the film (polarizing film) after stretching is preferably 5 to 35 ⁇ m, particularly 20 to 30 ⁇ m.
- uniaxial stretching in the case of uniaxially stretching a long PVA film there is no particular limitation on the direction of uniaxial stretching in the case of uniaxially stretching a long PVA film, and uniaxial stretching in the longitudinal direction or transverse uniaxial stretching can be adopted, but a polarizing film having excellent polarization performance can be obtained.
- Uniaxial stretching in the longitudinal direction is preferred. Uniaxial stretching in the longitudinal direction can be performed by changing the circumferential speed between the rolls using a stretching apparatus comprising a plurality of rolls parallel to one another.
- transverse uniaxial stretching can be performed using a tenter-type stretching machine.
- a fixing treatment in order to strengthen the adsorption of the dye onto the uniaxially stretched film.
- a fixing process the method of immersing a film in the fixed process bath which added boron compounds, such as a boric acid and borax, is mentioned. At this time, if necessary, an iodine compound may be added to the fixing treatment bath.
- the temperature of the drying treatment is preferably in the range of 30 to 150 ° C., particularly preferably in the range of 50 to 140 ° C.
- the temperature of the drying treatment (heat treatment) is too low, the dimensional stability of the obtained polarizing film is likely to be reduced, while when it is too high, the polarization performance is apt to be degraded due to the decomposition of the dye.
- a protective film having optical transparency and mechanical strength can be bonded to both surfaces or one surface of the polarizing film obtained as described above to make a polarizing plate.
- a protective film in that case, a cellulose triacetate (TAC) film, a cellulose acetate / butyrate (CAB) film, an acrylic film, a polyester film, etc. are used.
- a PVA-type adhesive agent, a urethane type adhesive agent, etc. are mentioned, Among these, a PVA-type adhesive agent is preferable.
- the polarizing plate obtained as described above can be used as a component of a liquid crystal display device after being coated with an acrylic or other pressure-sensitive adhesive and then bonded to a glass substrate.
- a retardation film, a viewing angle improving film, a brightness improving film, or the like may be bonded.
- the retardation value of the PVA film just before being taken up through the drying step was measured.
- the retardation value in the thickness direction of the film at 25 ° C. was measured based on the light having a wavelength of 590 nm using a plurality of retardation measurement devices arranged in the vertical direction with respect to the flow direction of the film.
- the number average value Re total of the retardation of all measurement points was determined.
- Example 1 Production of PVA film 100 parts by mass of PVA (saponified product of homopolymer of vinyl acetate, polymerization degree 2,400, degree of saponification 99.9 mol%), glycerin 12 parts by mass, lauric acid diethanolamide 0.1 mass A film-forming stock solution with a volatile fraction of 66% by mass, consisting of 1 part and water, was used.
- a film forming apparatus one provided with a T-shaped slit die (width 4.9 m) and 18 drying rolls whose rotation axes are parallel to each other was used.
- the casting dope first drying roll (surface temperature 93.5 ° C., a peripheral speed (S 1) 14.5 m / min) from a T-slit die was discharged onto a film.
- hot air (temperature 90 ° C., dew point temperature 10 ° C.) was uniformly blown over the film on the first drying roll at a wind speed of 5 m / sec.
- the film is peeled off from the first drying roll (the volatile fraction of the film immediately after peeling off from the first drying roll is 18.2% by mass), and the film surface not in contact with the first drying roll is the second drying roll It was dried by contacting with The film was dried by sequentially contacting the third drying roll to the eighteenth drying roll so that one side and the other side of the film alternately contact each drying roll. Then, after cutting both ends (ears) of the film, it was wound up in a roll to obtain a PVA film (thickness 60 ⁇ m, width 4 m, length 5,000 m, volatile fraction 3% by mass). After cutting both ends of the film, the retardation value of the PVA film was measured by the above method before winding.
- the volatile fraction of the film was determined as follows. Immediately after the film was peeled off from the first drying roll, a sample was taken from the center of the film. In addition, samples were collected from the center of the film immediately before contacting the second to eighteenth drying rolls. Each sample was dried in a dryer at 105 ° C. for 16 hours, and then the volatile fraction was determined from the mass of the film before and after drying.
- the surface temperature of each drying roll is shown in Table 2, and the peripheral speed ratio of adjacent drying rolls is shown in Table 3.
- the ratio (S 7 / S 2 ) of the peripheral speed (S 7 ) of the seventh drying roll to the peripheral speed (S 2 ) of the second drying roll is 0.971, and the peripheral speed (S 1 ) of the first drying roll
- the ratio (S 2 / S 1 ) of the peripheral speed (S 2 ) of the second drying roll to the above was 1.050.
- the average of the roll surface temperature of the second to x-th drying rolls was 80 ° C. The results are shown in Table 1. Also, calculated A, B, Re total and A / Re total using retardation values of the PVA film are shown in Table 1.
- a film roll of the obtained PVA film was continuously subjected to swelling treatment, dyeing, uniaxial stretching, and drying treatment in this order to produce a polarizing film.
- the PVA film was immersed in distilled water for 1 minute as swelling treatment. Subsequently, it was immersed in an aqueous solution containing an iodine dye (iodine concentration: 0.3% by mass, potassium iodide concentration: 2.1% by mass, temperature 30 ° C.) for 1 minute to contain the iodine dye.
- an iodine dye iodine concentration: 0.3% by mass, potassium iodide concentration: 2.1% by mass, temperature 30 ° C.
- the width of the obtained polarizing film was measured every 100 m, and the difference ⁇ (cm) between the maximum value and the minimum value was calculated.
- the percentage (100 ⁇ ⁇ / ⁇ ) of the difference ⁇ (cm) to the PVA film width ⁇ (cm) of the raw fabric was calculated.
- the percentage is less than 0.5%, the evaluation of the width fluctuation is A, and when the percentage is 0.5% or more and less than 1.0%, the evaluation of the width fluctuation is B, and the width is 1.0% or more Evaluation of fluctuation is C.
- the PVA film of the present invention satisfying the above formulas (1) to (4) is excellent in excellent stretchability, and the width at the time of stretching is also uniform.
- the ratio of the peripheral speed of the x drying roll (S x) (S x / S 2) is less than 0.970, the x drying roll from the second drying roll When the average roll temperature exceeds 81 ° C.
- a and B of the obtained PVA film exceed the upper limits defined by the above formulas (1) and (2), and the stretchability is And the uniformity of the width at the time of stretching decreased.
- a and B are indices of retardation spots in the lengthwise direction of the PVA film, and the PVA films of Comparative Examples 1 and 2 having large values of these are considered to have insufficient optical performance of the obtained optical film Be
- a and B of the resulting PVA film are defined by the above formulas (1) and (2)
- the PVA film of Comparative Example 3 in which A and B are large is considered to be insufficient in the optical performance of the resulting optical film.
- the ratio (S x ) of the peripheral speed (S x ) of the xth drying roll to the peripheral speed (S 2 ) of the second drying roll is lower than 63 ° C.
- Reference Example 1 is an example in which, when cutting both ends of a PVA film formed in the same manner as Comparative Example 3, the end portion is cut wider than in Comparative Example 3. Although the performance of the obtained PVA film was sufficient, since the width was narrow, there was a problem in practical use.
- Reference Example 2 is an example of a conventional thick (75 ⁇ m) PVA film.
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Abstract
Description
Remax(nm):端から10mmの位置におけるレターデーションの最大値
Remin(nm):端から10mmの位置におけるレターデーションの最小値
Reave(nm):端から10mmの位置におけるレターデーションの平均値
Rei(nm):端から10mmの位置における測定点i(i=1~n、nは整数)のレターデーション値
Retotal(nm):全測定点のレターデーションの平均値
である。 During the ceremony
Re max (nm): maximum retardation Re min (nm) at a
Remax(nm):端から10mmの位置におけるレターデーションの最大値
Remin(nm):端から10mmの位置におけるレターデーションの最小値
Reave(nm):端から10mmの位置におけるレターデーションの平均値
Rei(nm):端から10mmの位置における測定点i(i=1~n、nは整数)のレターデーション値
Retotal(nm):全測定点のレターデーションの平均値、
である。 During the ceremony
Re max (nm): maximum retardation Re min (nm) at a
It is.
Re=d×Δn
[式中、dはフィルム厚み(nm)、Δnはフィルムの複屈折である。] In the PVA film of the present invention, the retardation value measured with the pitch in the length direction being 15 m and the pitch in the width direction being 10 mm, the above formulas (1) to (4) are satisfied. Here, the retardation Re (nm) of the film is represented by the following formula. Specifically, the retardation Re (nm) of the PVA film can be measured by the method described in the examples.
Re = d × Δn
[Wherein, d is the film thickness (nm) and Δn is the birefringence of the film. ]
[式中、Waは製膜原液の質量(g)、WbはWa(g)の製膜原液を105℃の電熱乾燥機中で16時間乾燥した後に残存する成分の質量(g)を示す。] Volatile fraction (mass%) = {(Wa−Wb) / Wa} × 100 (i)
[Wherein, Wa represents the mass (g) of the membrane-forming solution, Wb represents the mass (g) of the component remaining after drying the membrane-forming solution of Wa (g) in the electrothermal dryer at 105 ° C. for 16 hours. ]
[式中、Wcは採取されたフィルムの質量(g)、Wdは前記フィルムWc(g)を温度105℃の乾燥機中で16時間乾燥させた後のフィルムの質量(g)を示す。] Volatile fraction (mass%) = {(Wc−Wd) / Wc} × 100 (ii)
[Wherein, Wc represents the mass (g) of the collected film, and Wd represents the mass (g) of the film after the film Wc (g) was dried in a dryer at a temperature of 105 ° C. for 16 hours. ]
乾燥工程を経て巻き取られる直前のPVAフィルムのレターデーション値を測定した。フィルムの流れ方向に対して、垂直方向に複数並べられたレターデーション測定装置を用いて、波長590nmの光に基づいて、25℃における、フィルムの厚み方向のレターデーション値を測定した。フィルムの長さ方向(流れ方向)のピッチを15m、幅方向のピッチを10mmとしてフィルム全面のレターデーション値を測定した後、全測定点のレターデーションの数平均値Retotalを求めた。さらに、PVAフィルムの端から10mmの位置における測定点i(i=1~n、nは整数)のレターデーション(Rei)から、その最大値(Remax)、最小値(Remin)、数平均値(Reave)を上記の方法により求めた後、上記式(1)、(2)に導入してA及びBを算出した。 Measurement of Retardation Value The retardation value of the PVA film just before being taken up through the drying step was measured. The retardation value in the thickness direction of the film at 25 ° C. was measured based on the light having a wavelength of 590 nm using a plurality of retardation measurement devices arranged in the vertical direction with respect to the flow direction of the film. After measuring the retardation value of the whole film surface by setting the pitch in the length direction (flow direction) of the film to 15 m and the pitch in the width direction to 10 mm, the number average value Re total of the retardation of all measurement points was determined. Furthermore, from the retardation (Re i ) of the measurement point i (i = 1 to n, n is an integer) at a position of 10 mm from the end of the PVA film, its maximum value (Re max ), minimum value (Re min ), number After the average value (Re ave ) was determined by the above method, A and B were calculated by introducing them into the above formulas (1) and (2).
(1)PVAフィルムの製造
PVA(酢酸ビニルの単独重合体のけん化物、重合度2,400、けん化度99.9モル%)100質量部、グリセリン12質量部、ラウリン酸ジエタノールアミド0.1質量部および水からなる揮発分率66質量%の製膜原液を用いた。製膜装置として、T型スリットダイ(幅4.9m)と、回転軸が互いに平行な18個の乾燥ロールを備えるものを用いた。前記製膜原液をT型スリットダイから第1乾燥ロール(表面温度93.5℃、周速(S1)14.5m/分)上にフィルム状に吐出した。このとき、第1乾燥ロール上のフィルムに熱風(温度90℃、露点温度10℃)を5m/秒の風速でフィルム全体に均一に吹き付けた。次いで第1乾燥ロールからフィルムを剥離して(第1乾燥ロールから剥離した直後のフィルムの揮発分率は18.2質量%)、第1乾燥ロールと接触しなかったフィルム面を第2乾燥ロールに接触させて乾燥を行った。フィルムの一面と他面が交互に各乾燥ロールに接するように、当該フィルムを第3乾燥ロールから第18乾燥ロールに順次接触させることにより乾燥を行った。その後、フィルムの両端部(耳)を切断した後、ロール状に巻き取って、PVAフィルム(厚み60μm、幅4m、長さ5,000m、揮発分率3質量%)を得た。フィルムの両端部を切断した後、巻き取る前に上記方法によりPVAフィルムのレターデーレーション値を測定した。フィルムの揮発分率は次のように求めた。第1乾燥ロールからフィルムが剥離した直後にフィルムの中央部からサンプルを採取した。また、第2~第18乾燥ロールに接触する直前のフィルムの中心部からサンプルをそれぞれ採取した。各サンプルを105℃の乾燥機中で16時間乾燥させた後、乾燥前後のフィルムの質量から揮発分率を求めた。各乾燥ロールの表面温度を表2に示し、隣接する乾燥ロールの周速比を表3に示す。 Example 1
(1) Production of PVA film 100 parts by mass of PVA (saponified product of homopolymer of vinyl acetate, polymerization degree 2,400, degree of saponification 99.9 mol%), glycerin 12 parts by mass, lauric acid diethanolamide 0.1 mass A film-forming stock solution with a volatile fraction of 66% by mass, consisting of 1 part and water, was used. As a film forming apparatus, one provided with a T-shaped slit die (width 4.9 m) and 18 drying rolls whose rotation axes are parallel to each other was used. The casting dope first drying roll (surface temperature 93.5 ° C., a peripheral speed (S 1) 14.5 m / min) from a T-slit die was discharged onto a film. At this time, hot air (temperature 90 ° C.,
以下のとおり、得られたPVAフィルムのフィルムロールを連続的に膨潤処理、染色、一軸延伸、乾燥処理をこの順で施して偏光フィルムを製造した。膨潤処理としてPVAフィルムを蒸留水に1分間浸漬した。次いで、ヨウ素系色素を含有する水溶液(ヨウ素濃度:0.3質量%、ヨウ化カリウム濃度:2.1質量%、温度30℃)に1分間浸漬してヨウ素系色素を含有させた。続いて、ホウ酸水溶液(ホウ酸濃度:4質量%、ヨウ化カリウム濃度:6質量%、温度:60℃)中で流れ方向に6.2倍に延伸した。その後、60℃で1分間乾燥させ、偏光フィルムを得た。上記条件で1,000mのPVAフィルムロールを延伸した際の破断発生回数が0回の場合に延伸性の評価をAとし、1~3回の場合に延伸性の評価をBとし、4回以上の場合に延伸性の評価をCとした。 Evaluation of Stretchability As described below, a film roll of the obtained PVA film was continuously subjected to swelling treatment, dyeing, uniaxial stretching, and drying treatment in this order to produce a polarizing film. The PVA film was immersed in distilled water for 1 minute as swelling treatment. Subsequently, it was immersed in an aqueous solution containing an iodine dye (iodine concentration: 0.3% by mass, potassium iodide concentration: 2.1% by mass, temperature 30 ° C.) for 1 minute to contain the iodine dye. Subsequently, it was stretched 6.2 times in the flow direction in a boric acid aqueous solution (boric acid concentration: 4% by mass, potassium iodide concentration: 6% by mass, temperature: 60 ° C.). Then, it was made to dry at 60 degreeC for 1 minute, and the polarizing film was obtained. Evaluation of the stretchability is A when the number of breakage occurrence when stretching a 1,000 m PVA film roll is 0 under the above conditions is A, and the stretchability evaluation is B when it is 1 to 3 times, 4 or more times The evaluation of stretchability was C in the case of.
得られた偏光フィルムの幅を100mおきに測定し、その最大値と最小値の差α(cm)を算出した。原反のPVAフィルム幅β(cm)に対する前記差α(cm)の百分率(100×α/β)を算出した。当該百分率が0.5%未満の場合に幅変動の評価をAとし、0.5%以上~1.0%未満の場合に幅変動の評価をBとし、1.0%以上の場合に幅変動の評価をCとした。 Evaluation of Width Variation The width of the obtained polarizing film was measured every 100 m, and the difference α (cm) between the maximum value and the minimum value was calculated. The percentage (100 × α / β) of the difference α (cm) to the PVA film width β (cm) of the raw fabric was calculated. When the percentage is less than 0.5%, the evaluation of the width fluctuation is A, and when the percentage is 0.5% or more and less than 1.0%, the evaluation of the width fluctuation is B, and the width is 1.0% or more Evaluation of fluctuation is C.
PVAフィルムの製造条件を表1~3のとおりにしたこと以外は実施例1と同様にしてPVAフィルムの製造及び評価を行った。結果を表1に示した。
Examples 2, 3 Comparative Examples 1 to 4, Reference Examples 1 and 2
The production and evaluation of a PVA film were carried out in the same manner as in Example 1 except that the production conditions of the PVA film were as shown in Tables 1 to 3. The results are shown in Table 1.
2、3 端
4 長さ方向
5 ピッチ
6 幅方向
1
Claims (3)
- 幅3m以上、長さ1,000m以上、厚み15~65μmのポリビニルアルコールフィルムであって、
長さ方向のピッチを15m、幅方向のピッチを10mmとして測定されたレターデーション値が下記式(1)~(4)を満足することを特徴とするポリビニルアルコールフィルム。
式中、
Remax(nm):端から10mmの位置におけるレターデーションの最大値
Remin(nm):端から10mmの位置におけるレターデーションの最小値
Reave(nm):端から10mmの位置におけるレターデーションの平均値
Rei(nm):端から10mmの位置における測定点i(i=1~n、nは整数)のレターデーション値
Retotal(nm):全測定点のレターデーションの平均値
である。 A polyvinyl alcohol film with a width of 3 m or more, a length of 1,000 m or more, and a thickness of 15 to 65 μm,
A polyvinyl alcohol film characterized in that a retardation value measured by setting a pitch in the length direction to 15 m and a pitch in the width direction to 10 mm satisfies the following formulas (1) to (4).
During the ceremony
Re max (nm): maximum retardation Re min (nm) at a position 10 mm from the edge: minimum retardation Re ave (nm) at a position 10 mm from the edge: average retardation at a position 10 mm from the edge Value Re i (nm): Retardation value Re total (nm) of measurement point i (i = 1 to n, n is an integer) at a position of 10 mm from the end: Average value of retardation of all measurement points. - 請求項1に記載のポリビニルアルコールフィルムの製造方法であって、
回転軸が互いに平行な複数の乾燥ロールを備える製膜装置を使用し、
前記複数の乾燥ロールが、第1乾燥ロールから第m乾燥ロール(mは3以上の整数を示す)からなり、
ダイから第1乾燥ロール上にポリビニルアルコールを含む製膜原液を吐出して乾燥させることによってフィルムを得た後に、第2乾燥ロール~第m乾燥ロールを用いて前記フィルムをさらに乾燥させる工程を有し、
第1乾燥ロールから剥離するときのフィルムの揮発分率が12~20%であり、
第1乾燥ロールの周速(S1)に対する第2乾燥ロールの周速(S2)の比(S2/S1)が1.015~1.050であり、
第2乾燥ロールの周速(S2)に対する、前記フィルムの揮発分率が11質量%以下になってから初めて接触する乾燥ロール(第x乾燥ロール)の周速(Sx)の比(Sx/S2)が0.970~0.995であり、
第2乾燥ロールから第x乾燥ロールまでのロール温度の平均が63~81℃である、ポリビニルアルコールフィルムの製造方法。 The method for producing a polyvinyl alcohol film according to claim 1,
Using a film forming apparatus comprising a plurality of drying rolls whose rotation axes are parallel to one another
The plurality of drying rolls consist of a first drying roll to an m-th drying roll (m represents an integer of 3 or more),
After a film is obtained by discharging a film-forming solution containing polyvinyl alcohol onto a first drying roll from a die and drying, a step of further drying the film using a second drying roll to a m-th drying roll is included. And
The volatile fraction of the film when peeled off from the first drying roll is 12 to 20%,
The ratio (S 2 / S 1 ) of the peripheral speed (S 2 ) of the second drying roll to the peripheral speed (S 1 ) of the first drying roll is 1.015 to 1.050,
Ratio (S x ) of the peripheral speed (S x ) of the drying roll (Xth drying roll) to be contacted only after the volatile fraction of the film becomes 11% by mass or less with respect to the peripheral speed (S 2 ) of the second drying roll x / S 2 ) is 0.970 to 0.995,
A method for producing a polyvinyl alcohol film, wherein the average roll temperature from the second drying roll to the x-th drying roll is 63 to 81 ° C. - ポリビニルアルコールを含む製膜原液の揮発分率が60~75質量%であり、第1乾燥ロールの周速(S1)が8~25m/分である、請求項2に記載のポリビニルアルコールフィルムの製造方法。 The polyvinyl alcohol film according to claim 2, wherein the volatile content of the membrane-forming solution containing polyvinyl alcohol is 60 to 75% by mass, and the peripheral speed (S 1 ) of the first drying roll is 8 to 25 m / min. Production method.
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PCT/JP2018/034204 WO2019054487A1 (en) | 2017-09-15 | 2018-09-14 | Polyvinyl alcohol film and method for manufacturing same |
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JP (1) | JP7157751B2 (en) |
KR (1) | KR102599701B1 (en) |
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JP2022022085A (en) * | 2020-07-22 | 2022-02-03 | 住友化学株式会社 | Method for manufacturing polarization film and polyvinyl alcohol film |
WO2022113959A1 (en) * | 2020-11-26 | 2022-06-02 | 株式会社クラレ | Polyvinyl alcohol film, polarizing film using same, and polarizing plate |
WO2023074639A1 (en) * | 2021-10-25 | 2023-05-04 | 株式会社クラレ | Polyvinyl alcohol film |
WO2023127874A1 (en) * | 2021-12-28 | 2023-07-06 | 株式会社クラレ | Polyvinyl alcohol film and method for producing polyvinyl alcohol film |
WO2023182249A1 (en) * | 2022-03-22 | 2023-09-28 | 三菱ケミカル株式会社 | Polyvinyl alcohol film, polarizing film using same, and polarizing plate |
WO2023182250A1 (en) * | 2022-03-22 | 2023-09-28 | 三菱ケミカル株式会社 | Polyvinyl alcohol-based film, and polarizing film and polarizing plate using same |
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- 2018-09-14 WO PCT/JP2018/034204 patent/WO2019054487A1/en active Application Filing
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TW201920393A (en) | 2019-06-01 |
KR20200053523A (en) | 2020-05-18 |
TWI765093B (en) | 2022-05-21 |
JPWO2019054487A1 (en) | 2020-10-29 |
CN111405972B (en) | 2022-09-02 |
KR102599701B1 (en) | 2023-11-07 |
CN111405972A (en) | 2020-07-10 |
JP7157751B2 (en) | 2022-10-20 |
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