WO2016093259A1 - Polyvinyl alcohol polymer film and method for producing same - Google Patents
Polyvinyl alcohol polymer film and method for producing same Download PDFInfo
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- WO2016093259A1 WO2016093259A1 PCT/JP2015/084464 JP2015084464W WO2016093259A1 WO 2016093259 A1 WO2016093259 A1 WO 2016093259A1 JP 2015084464 W JP2015084464 W JP 2015084464W WO 2016093259 A1 WO2016093259 A1 WO 2016093259A1
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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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- 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
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L29/00—Compositions 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; Compositions of hydrolysed polymers of esters of unsaturated alcohols with saturated carboxylic acids; Compositions of derivatives of such polymers
- C08L29/02—Homopolymers or copolymers of unsaturated alcohols
- C08L29/04—Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
- G02B1/08—Optical elements characterised by the material of which they are made; Optical coatings for optical elements made of polarising materials
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/30—Polarising elements
- G02B5/3025—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state
- G02B5/3033—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid
-
- 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 polymer film having a thickness of 50 ⁇ m or less (hereinafter, “polyvinyl alcohol polymer” may be abbreviated as “PVA”), a production method thereof, and a polarization produced from the PVA film.
- PVA polyvinyl alcohol polymer
- the present invention relates to an optical film such as a film.
- a polarizing plate having a light transmission and shielding function is an important component of a liquid crystal display (LCD) together with a liquid crystal having a light switching function.
- LCD liquid crystal display
- This LCD can be applied to small devices such as calculators and watches in the early days of development, notebook computers, liquid crystal monitors, liquid crystal color projectors, liquid crystal televisions, in-vehicle navigation systems, mobile phones, measuring devices used indoors and outdoors, etc.
- LCD liquid crystal display
- LCD liquid crystal having a light switching function
- a polarizing plate is a method in which a long PVA film wound in a roll is unwound and uniaxially stretched and then dyed using iodine or a dichroic dye, and the unrolled PVA film is dyed and uniaxially stretched.
- a polarizing film is produced by a method of performing a fixing treatment with a boron compound, a method of performing a fixing treatment simultaneously with dyeing in any of the above methods, and a cellulose triacetate film on one or both sides of the polarizing film obtained thereby. It is manufactured industrially by laminating a protective film such as an acetic acid / butyric acid cellulose film.
- the protective film thin, which occupies most of the thickness of the polarizing plate.
- the protective film If only the thin film is made thin, there is a problem that the entire polarizing plate is easily deformed. For this problem, it is conceivable to make the polarizing film itself thinner by using a thinner PVA film as a raw film.
- (TD) ratio in the direction of the degree of swelling (X TD) and machine direction (MD) degree of swelling (X MD) is known PVA film in the range of 1.000 to 1.020 (See Patent Document 1).
- a PVA film when immersed in water, it swells and extends in the length direction and width direction.
- a thin PVA film has a relatively thick PVA due to a high drying speed in the film forming process.
- the amount of elongation in the length direction during swelling is relatively smaller than the amount of elongation in the width direction during swelling compared to the film.
- by changing the crystallinity of the PVA film for example, by changing the heat treatment conditions, it is possible to increase or decrease both the amount of elongation in the length direction and the width direction during swelling.
- the amount of elongation in the length direction is set to a specific value or more in order to improve the stretchability, the amount of elongation in the width direction becomes too large.
- a polarizing film conventionally used When the polarizing film is manufactured by the manufacturing apparatus, the end of the swollen PVA film is likely to be in contact with the wall of the apparatus, and an abnormal end is likely to occur.
- the elongation in the width direction becomes too small and the stretchability is lowered. In some cases, the resulting polarizing film is dyed.
- the present invention provides a thin PVA film that can easily produce a thin PVA film that has excellent stretchability and is less likely to cause abnormal end portions during use, and preferably a thin polarizing film with reduced dyeing spots.
- an object of this invention is to provide optical films, such as a polarizing film manufactured from the said PVA film.
- the inventors of the present invention have a specific range of elongation in the length direction (MD) when immersed in water at 30 ° C. for 30 seconds in a thin PVA film. And adjusting the elongation in the width direction (TD) when immersed in water at 30 ° C. for 300 seconds to a specific range, it is excellent in stretchability even when it is a thin PVA film. It has been found that the PVA film can be easily produced as a thin polarizing film in which abnormal end portions are hardly generated and the dyeing spots are reduced.
- the inventors of the present invention when manufacturing a thin PVA film using a film forming apparatus including a plurality of drying rolls and a plurality of heat treatment rolls whose rotation axes are parallel to each other, By making the ratio of the peripheral speed between the heat treatment roll located on the most downstream side within a specific range and the surface temperature of the heat treatment roll within a specific range, the above PVA film can be produced smoothly and continuously with high productivity. Found that you can.
- the present inventors have further studied based on these findings and completed the present invention.
- a PVA film having a thickness of 50 ⁇ m or less, and when the sample of the PVA film is immersed in water at 30 ° C. for 30 seconds, an elongation amount W MD30 in a length direction in a portion having a length direction of 250 mm before immersion is A PVA film that is 35 mm or more and 60 mm or less, and has a width direction extension amount W TD300 of 53 mm or more and 65 mm or less in a 250 mm width portion before immersion when the PVA film sample is immersed in water at 30 ° C. for 300 seconds.
- the film-forming stock solution is discharged in a film form and dried, followed by further drying with a drying roll, and then heat treatment with a plurality of heat treatment rolls to produce a PVA film, where the heat treatment roll located on the most upstream side Is the heat treatment roll A, and the heat treatment roll located on the most downstream side is the heat treatment roll B, the volatile fraction of the PVA film immediately before contacting the heat treatment roll A is 3% by mass or more and 7% by mass or less.
- peripheral speed peripheral speed of the heat treatment roll B to (S a) of the roll a ratio (S B) (S B / S a) is 0.999 or less, from the heat treatment roll a to the heat treatment roll B of the heat treatment roll A production method wherein the surface temperature is 87 ° C.
- drying roll X When the drying roll when the volatile content ratio of the PVA film is 12% by mass is the drying roll X and the drying roll located immediately before the heat treatment roll A is the drying roll Y, the first drying roll The surface temperature of each drying roll up to the drying roll X is 70 ° C. or more, and the surface temperature of each drying roll from the drying roll located immediately after the drying roll X to the drying roll Y is 40 ° C. or more and 70 ° C.
- the production method of [6]; [8] When the drying roll located immediately before the heat treatment roll A is the drying roll Y, the front and back surfaces of the PVA film are alternately opposed to each drying roll between the first drying roll and the drying roll Y.
- a thin PVA film that is excellent in stretchability, hardly causes abnormal end portions during use, and can easily produce a thin polarizing film with reduced staining spots, and the PVA film.
- An optical film such as a produced polarizing film is provided.
- the manufacturing method of the PVA film which can manufacture the said PVA film continuously smoothly with sufficient productivity is provided.
- the present invention is described in detail below.
- the PVA film of the present invention has a thickness of 50 ⁇ m or less.
- elongation amount WMD30 of the length direction in the part of the length direction 250mm before immersion is 35 mm or more and 60 mm or less.
- the amount of elongation WTD300 in the width direction in the portion in the width direction 250 mm before immersion is more than 53 mm and not more than 65 mm.
- the thickness of the PVA film of the present invention is required to be 50 ⁇ m or less because a thin optical film can be obtained, and the thickness is preferably 45 ⁇ m or less, more preferably 40 ⁇ m or less. It is preferably 35 ⁇ m or less, particularly preferably 30 ⁇ m or less, and may be 20 ⁇ m or less. Thus, the effect of the present invention becomes more remarkable in a thin PVA film.
- the lower limit of the thickness of the PVA film is not particularly limited, but considering the handleability of the PVA film, the process passability during the production of the optical film, the optical performance of the resulting optical film (the polarizing performance of the polarizing film, etc.)
- the thickness is preferably 3 ⁇ m or more, more preferably 5 ⁇ m or more, further preferably 7 ⁇ m or more, and particularly preferably 10 ⁇ m or more.
- the thickness of the PVA film can be obtained as an average value obtained by measuring the thicknesses at arbitrary five locations.
- the PVA film of the present invention has a length (MD) elongation in a specific range when immersed in water at 30 ° C. for 30 seconds. Specifically, when the sample cut out from the PVA film of the present invention is immersed in water at 30 ° C. for 30 seconds, the elongation amount W MD30 in the length direction 250 mm before immersion is 35 mm or more and 60 mm or less. Is in range. When WMD30 is less than 35 mm, the PVA film is insufficiently swelled at the time of use, so that the plasticization of the film becomes insufficient and the stretchability is lowered. From this viewpoint, WMD30 is preferably 37 mm or more, more preferably 39 mm or more, and further preferably 42 mm or more.
- WMD30 exceeds 60 mm, the degree of swelling of the PVA film tends to be excessive, and the PVA film is wrinkled or broken due to the slackness of the PVA film generated thereby, and the breakage is based on this. It can happen.
- WMD30 is preferably 55 mm or less, more preferably 50 mm or less, further preferably 47 mm or less, and particularly preferably 46 mm or less.
- WMD30 the amount of elongation when a sample is immersed in water at 30 ° C. for 30 seconds is specified. This is a thin film when a thin PVA film is used to manufacture an optical film such as a polarizing film.
- the PVA film of the present invention has a specific range of elongation in the width direction (TD) when immersed in water at 30 ° C. for 300 seconds. Specifically, when the sample cut out of the PVA film of the present invention is immersed in water at 30 ° C. for 300 seconds, the width extension amount W TD300 in the width direction 250 mm portion before immersion is in the range of 53 mm to 65 mm. It is in. When WTD300 is less than 53 mm, stained spots are likely to occur in the obtained polarizing film. In this respect, W TD300 is preferably 54 mm or more, more preferably 55 mm or more, and further preferably 57 mm or more.
- WTD300 exceeds 65 mm, the PVA film is excessively spread in the width direction at the time of use, and end abnormalities such as film breakage tend to occur.
- W TD300 is preferably 62 mm or less, and more preferably 60 mm or less.
- WTD300 defines the amount of elongation when a sample is immersed in water at 30 ° C. for 300 seconds, and this correlates with the WMD300 and abnormal end portions at the time of use and staining spots of the obtained polarizing film. Because there is.
- Said WMD30 can be calculated
- TD width direction
- MD length direction
- the outer part from the marked lines at both ends is sandwiched between commercially available clips (chuck width 40 mm, mass 7.8 g (weight in water 7.3 g)), and one clip is fixed with a rod-shaped jig such as a number wire.
- a rod-shaped jig such as a number wire.
- a metal ruler is immersed in water, and the distance between marked lines is measured 30 seconds after the immersion of the sample.
- the elongation (W MD30 ) (unit: mm) is calculated by subtracting the original distance between marked lines (250 mm) from the measured value read in 0.5 mm increments.
- the WTD 300 can be obtained by the following method. That is, first, a rectangular sample of width direction (TD) 270 mm ⁇ length direction (MD) 40 mm is cut out from the PVA film to be measured. Here, for example, the sample may be cut out from the center in the width direction of the target PVA film. Next, a marked line is put with an oily magic (line thickness is 0.3 mm) inward by 10 mm from both ends of the 270 mm length of the sample. The outer part from the marked lines at both ends is sandwiched between commercially available clips (chuck width 40 mm, mass 7.8 g (weight in water 7.3 g)), and one clip is fixed with a rod-shaped jig such as a number wire.
- chuck width 40 mm, mass 7.8 g weight in water 7.3 g
- the PVA constituting the PVA film of the present invention those produced by saponifying a polyvinyl ester polymer obtained by polymerizing a vinyl ester can be used.
- the vinyl ester include vinyl formate, vinyl acetate, vinyl propionate, vinyl valelate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl pivalate, vinyl versatate, and the like.
- vinyl esters vinyl acetate is preferable from the viewpoints of availability, cost, ease of production of PVA, and the like.
- the above-mentioned polyvinyl ester polymer is preferably obtained using only one or two or more kinds of vinyl esters as a monomer, and obtained using only one kind of vinyl ester as a monomer. Is more preferable, but it may be a copolymer of one or more vinyl esters and other monomers copolymerizable therewith.
- Examples of such other monomers copolymerizable with vinyl ester include ethylene; olefins having 3 to 30 carbon atoms such as propylene, 1-butene and isobutene ( ⁇ -olefins); acrylic acid or a salt thereof.
- 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-butyl, 2-ethylhexyl methacrylate, methacryl Methacrylic acid esters such as dodecyl and octadecyl methacrylate; acrylamide; N-methyl acrylamide, N-ethyl
- the proportion of structural units derived from the other monomers in the polyvinyl ester polymer is 15 mol% or less based on the number of moles of all structural units constituting the polyvinyl ester polymer. Preferably, it is 10 mol% or less, more preferably 5 mol% or less.
- the above PVA may be modified with one or two or more types of graft copolymerizable monomers.
- the graft copolymerizable monomer include unsaturated carboxylic acids or derivatives thereof; unsaturated sulfonic acids or derivatives thereof; ⁇ -olefins having 2 to 30 carbon atoms, and the like.
- the proportion of structural units derived from the graft copolymerizable monomer in PVA is preferably 5 mol% or less based on the number of moles of all structural units constituting PVA.
- the above PVA may have a part of its hydroxyl group cross-linked or not cross-linked. Moreover, said PVA may react with aldehyde compounds, such as acetaldehyde and a butyraldehyde, etc. to form an acetal structure, and the said PVA does not react with these compounds and does not form an acetal structure. May be.
- aldehyde compounds such as acetaldehyde and a butyraldehyde, etc.
- the degree of polymerization of PVA is not particularly limited, but from the viewpoint of the strength of the PVA film and the durability of the optical film produced from the PVA film, it is preferably 500 or more, more preferably 1,000 or more, It is more preferably 1,500 or more, and particularly preferably 2,000 or more. On the other hand, if the degree of polymerization is too high, it tends to lead to an increase in production cost and poor processability during film formation. Therefore, the degree of polymerization of PVA is preferably 10,000 or less, and is 9,000 or less. More preferably, it is more preferably 8,000 or less, and particularly preferably 7,000 or less. In this specification, the degree of polymerization of PVA means the average degree of polymerization measured according to the description of JIS K6726-1994.
- the saponification degree of PVA is not particularly limited, but is preferably 90 mol% or more, more preferably 95 mol% or more, from the viewpoint of optical performance or durability of an optical film produced from a PVA film, It is further preferably 98 mol% or more, particularly preferably 99 mol% or more, and may be 99.2 mol% or more.
- the saponification degree of PVA is preferably 99.99 mol% or less.
- the degree of saponification of PVA 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 of PVA. The proportion (mol%) occupied by 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 is acidic such as carboxyl group and sulfonic acid group.
- PVA having a functional group PVA having an acid anhydride group
- PVA having a basic functional group such as an amino group
- PVA having a functional group that promotes a crosslinking reaction such as a neutralized product thereof.
- the secondary processability of the PVA film may decrease due to the crosslinking reaction.
- the PVA film preferably contains neither PVA having an acidic functional group, PVA having an acid anhydride group, PVA having a basic functional group, or a neutralized product thereof.
- PVA produced by saponifying a polyvinyl ester polymer obtained by using only vinyl ester as a monomer, and / or only vinyl ester and ethylene and / or olefin having 3 to 30 carbon atoms It is more preferable to include only PVA produced by saponifying a polyvinyl ester polymer obtained using a monomer, and as a PVA, a polyvinyl ester system obtained using only a vinyl ester as a monomer PVA produced by saponifying the polymer and / or vinyl ester and ethyl That is more preferably containing only PVA produced by saponifying a polyvinyl ester polymer obtained by using a monomer N'nomi.
- the PVA content in the PVA film is preferably in the range of 50 to 100% by mass, more preferably in the range of 80 to 100% by mass, and in the range of 85 to 100% by mass. Further preferred.
- the PVA film of the present invention preferably contains a plasticizer because it can improve mechanical properties such as impact strength and process passability during secondary processing.
- a plasticizer polyhydric alcohol is preferably used, and examples thereof include ethylene glycol, glycerin, diglycerin, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, and trimethylolpropane.
- the PVA film of the present invention can contain one or more of these plasticizers.
- these plasticizers one or more of glycerin, diglycerin and ethylene glycol are preferred from the viewpoint of excellent stretchability when the PVA film of the present invention is stretched and used.
- the content of the plasticizer in the PVA film is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and more preferably 5 parts by mass or more with respect to 100 parts by mass of PVA contained in the PVA film. More preferably, it is preferably 30 parts by mass or less, more preferably 25 parts by mass or less, and further preferably 20 parts by mass or less.
- the content is 1 part by mass or more, the stretchability of the PVA film can be further improved.
- the content is 30 parts by mass or less, the handleability of the PVA film is improved.
- the PVA film of the present invention preferably contains a surfactant from the viewpoint of its handleability and the improvement of peelability from the film forming apparatus when the PVA film is produced.
- a surfactant from the viewpoint of its handleability and the improvement of peelability from the film forming apparatus when the PVA film is produced.
- surfactant for example, anionic surfactant, nonionic surfactant, etc. are mentioned.
- anionic surfactant examples include carboxylic acid types such as potassium laurate; sulfate ester types such as octyl sulfate; and sulfonic acid types such as dodecylbenzene sulfonate.
- Nonionic surfactants include, for example, alkyl ether types such as polyoxyethylene oleyl ether; alkylphenyl ether types such as polyoxyethylene octylphenyl ether; alkyl ester types such as polyoxyethylene laurate; polyoxyethylene laurylamino Alkylamine type such as 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; polyoxy Examples include allyl phenyl ether type such as alkylene allyl phenyl ether.
- the PVA film of the present invention can contain one or more of these surfactants.
- these surfactants nonionic surfactants are preferred because of their excellent effect of reducing film surface abnormalities during film formation, and alkanolamide type surfactants are particularly preferred, and aliphatic carboxylic acids (for example, Further, dialkanolamides (for example, diethanolamides, etc.) of C8-30 saturated or unsaturated aliphatic carboxylic acids) are more preferred.
- the content of the surfactant in the PVA film is such that the handleability of the PVA film and the peelability from the film forming apparatus when producing the PVA film can be further improved, and the occurrence of blocking can be reduced. It is preferably 0.01 parts by mass or more, more preferably 0.02 parts by mass or more, further preferably 0.05 parts by mass or more, relative to 100 parts by mass of PVA contained in the PVA film. Moreover, it is preferable that it is 1 mass part or less, It is more preferable that it is 0.5 mass part or less, It is further more preferable that it is 0.3 mass part or less.
- the PVA film of the present invention is optionally provided with stabilizers (antioxidants, ultraviolet absorbers, heat stabilizers, etc.), compatibilizers, antiblocking agents, flame retardants, antistatic agents, lubricants, dispersants, Various additives such as a fluidizing agent and an antibacterial agent may be included.
- stabilizers antioxidants, ultraviolet absorbers, heat stabilizers, etc.
- compatibilizers antiblocking agents, flame retardants, antistatic agents, lubricants, dispersants
- Various additives such as a fluidizing agent and an antibacterial agent may be included.
- the PVA film of the present invention can contain one or more of these additives.
- the volatile content of the PVA film is preferably in the range of 1% by mass or more and 5% by mass or less from the viewpoint of handleability, and the volatile content is more preferably 2% by mass or more. More preferably, it is 4 mass% or less.
- the volatile content of the PVA film can be determined in the same manner as the volatile content of the PVA film described later.
- the shape of the PVA film of the present invention is not particularly limited, but a more uniform PVA film can be continuously and smoothly manufactured, and is also continuous when an optical film such as a polarizing film is manufactured using the PVA film. It is preferable that the film is a long film.
- the long film is preferably in the form of a film roll by winding it around a cylindrical core.
- the length of the PVA film (length in the length direction (MD)) is not particularly limited and can be set as appropriate according to the use, etc., but is continuously wound from the film roll.
- the length is preferably 5 m or more, and more preferably 100 m or more. , 500 m or more, more preferably 1,000 m or more, 5,000 m or more, and even 8,000 m or more.
- the said length can be 50,000 m or less, for example, Furthermore, it can be 20,000 m or less.
- the width of the PVA film of the present invention is not particularly limited, and can be set as appropriate according to the use of the PVA film or an optical film such as a polarizing film produced from the PVA film. In view of the progress of screen formation, it is suitable for these uses when the width of the PVA film is 2 m or more, more preferably 3 m or more, and further preferably 4 m or more. On the other hand, if the width of the PVA film is too wide, it is difficult to uniformly carry out uniaxial stretching itself when producing an optical film with a device that has been put to practical use, so the width of the PVA film should be 8 m or less. Is preferably 7 m or less, and may be 6 m or less.
- the manufacturing method of the PVA film of this invention is not specifically limited, According to the manufacturing method of the following this invention, the PVA film of this invention can be manufactured smoothly with sufficient productivity.
- the manufacturing method of the present invention for manufacturing a PVA film having a thickness of 50 ⁇ m or less uses a film forming apparatus including a drying roll and a heat treatment roll whose rotation axes are parallel to each other, and the first drying roll of the film forming apparatus.
- a film-forming stock solution containing PVA is discharged into a film and dried, followed by further drying with a drying roll, and then heat treatment with a plurality of heat treatment rolls to produce a PVA film.
- the heat treatment roll located is heat treatment roll A and the heat treatment roll located on the most downstream side is heat treatment roll B
- the volatile fraction of the PVA film immediately before contacting the heat treatment roll A is 3 mass% or more and 7 mass% or less.
- the ratio (S B / S A ) of the peripheral speed (S B ) of the heat treatment roll B to the peripheral speed (S A ) of the heat treatment roll A is 0.999 or less, and the heat treatment roll A to the heat treatment roll B
- Each of the heat treatment rolls has a surface temperature of 87 ° C. or higher and 121 ° C. or lower.
- a more uniform PVA film can be obtained, and the number of drying rolls may be 4 or more. Preferably, it is 5 or more, more preferably 6 or more, particularly preferably 8 or more, preferably 30 or less, more preferably 20 or less. preferable.
- the drying roll drying roll which discharges film forming undiluted
- drying roll Y the drying roll when the volatile content of the PVA film during film formation becomes 12% by mass (or the drying roll on the downstream side when it becomes 12% by mass between two drying rolls) is “dried”
- drying roll Y The drying roll positioned immediately before the heat treatment roll is referred to as “drying roll Y”.
- the number of heat treatment rolls is not particularly limited as long as it is 2 or more. However, from the viewpoint of uniformly heat-treating both the front and back surfaces of the PVA film, the number of heat treatment rolls is 3 or more. Preferably, it is 4 or more, more preferably 10 or less, and even more preferably 8 or less.
- the heat treatment roll located on the most upstream side of the heat treatment rolls is referred to as “heat treatment roll A”, and the heat treatment roll located on the most downstream side is referred to as “heat treatment roll B”.
- the drying roll and / or heat treatment roll is preferably made of a metal such as nickel, chromium, copper, iron, stainless steel, and the like, and in particular, the surface of the roll is hard to corrode and has a specular gloss. More preferably, it is formed from.
- a roll plated with a single layer or a combination of two or more nickel layers, chromium layers, nickel / chromium alloy layers, etc. is used as the drying roll and / or heat treatment roll. It is preferable to use it.
- the PVA film In drying the PVA film using a plurality of drying rolls, the PVA film can be dried more uniformly, and in particular during the secondary processing of the PVA film obtained by reducing the physical property difference between the front and back surfaces of the PVA film. Since the film can be prevented from curling, it is preferable that the front and back surfaces of the PVA film are alternately opposed to each drying roll between the first drying roll and the drying roll Y.
- the film surface (first drying roll contact surface) that contacts the first drying roll and the first drying in any part of the PVA film It is preferable to dry so that the film surface that does not contact the roll (first drying roll non-contact surface) alternately faces each drying roll from the first drying roll to the drying roll Y.
- the PVA film when heat-treating a PVA film using a plurality of heat treatment rolls, the PVA film can be applied to each heat treatment roll between the heat treatment roll A and the heat treatment roll B because the heat treatment can be performed more uniformly. It is preferable that both the front and back sides of the front and back are alternately opposed.
- a film-forming stock solution containing PVA is discharged into a film shape on the first drying roll of the film-forming apparatus and dried.
- a known film-forming device such as a T-shaped slit die, a hopper plate, an I-die, or a lip coater die is used. May be discharged (cast) into a film on the first drying roll. At this time, the thickness of the obtained PVA film can be adjusted by adjusting the discharge amount by adjusting the film-like discharge device.
- the film-forming stock solution containing PVA can be prepared by mixing PVA with a liquid medium to form a solution, or melting a PVA chip containing the liquid medium or the like to form a melt.
- the film-forming stock solution can be prepared using a stirring mixer, a melt extruder, or the like.
- the liquid medium include water, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, ethylenediamine, and diethylenetriamine. These liquid media may be used alone. Or you may use 2 or more types together. Among these, water, dimethyl sulfoxide, or a mixture of both is preferably used, and water is particularly preferably used.
- the film-forming stock solution is preferably mixed with one or more of the plasticizers, surfactants, various additives and the like as described above in the description of the PVA film in the above-mentioned amounts.
- the volatile fraction of the film-forming stock solution is preferably in the range of 50% by mass or more and 90% by mass or less, and the volatile fraction is more preferably 55% by mass or more and 80% by mass or less. It is more preferable. If the volatile content is too low, the viscosity of the film-forming stock solution may become too high, making film formation difficult. On the other hand, if the volatile content is too high, the uniformity of the thickness of the obtained PVA film may be impaired.
- the volatile matter rate of the film-forming stock solution in this specification refers to the volatile matter rate obtained by the following formula (1).
- Volatile fraction (mass%) of the film-forming stock solution 100 ⁇ (W a ⁇ W b ) / W a (1) (Where, W a represents a film-forming stock solution mass (g), W b is W a (g) mass when a film-forming solution was dried 16 hours in a 105 ° C. of the heating dryer of (g) To express.)
- the surface temperature of the first drying roll is preferably in the range of 80 ° C. or higher and 120 ° C. or lower from the viewpoint of uniformity of drying of the PVA film, productivity, and the like, and the surface temperature is 85 ° C. or higher. Is more preferably 90 ° C. or higher, particularly preferably 93 ° C. or higher, more preferably 105 ° C. or lower, and further preferably 99 ° C. or lower.
- the surface temperature is 80 ° C. or higher, the drying efficiency on the first drying roll is improved.
- the surface temperature is 120 ° C. or lower, foaming of the PVA film can be more effectively suppressed.
- the film-forming stock solution discharged in the form of a film may be dried on the first drying roll only by the heat from the first drying roll, but at the same time as the first drying roll is heated, the first drying roll is not contacted. It is possible to apply heat from both sides of the PVA film by spraying hot air on the surface or by heating with an infrared heater from the first drying roll non-contact surface side. It is preferable from the point.
- the PVA film can also be heated by a dielectric heating device.
- the peripheral speed (S 1 ) of the first drying roll is preferably 8 m / min or more and 30 m / min or less from the viewpoint of the uniformity of drying of the PVA film, the drying speed, the productivity of the PVA film, and the like. It is more preferably from 27 to 27 m / min, even more preferably from 12 to 25 m / min.
- 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 peeled off from the first drying roll. If the volatile content of the PVA film at the time of peeling from the first drying roll is too low, the productivity of the PVA film tends to decrease, while the volatile content of the PVA film at the time of peeling from the first drying roll. If the rate is too high, peeling from the first drying roll is likely to be difficult, and in some cases, breakage or spots are likely to occur. From the above viewpoint, the volatile fraction of the PVA film at the time of peeling from the first drying roll is preferably 13% by mass or more, more preferably 14% by mass or more, and 15% by mass or more.
- the PVA film dried on the first drying roll is peeled off from the first drying roll, and this time, it is further dried by a drying roll after the second drying roll following the first drying roll.
- a drying roll In drying with the second drying roll, it is preferable that the first drying roll non-contact surface of the PVA film is opposed to the second drying roll.
- the surface temperature of each drying roll is not particularly limited, but the surface temperature of each drying roll from the first drying roll to the drying roll X is the same as that of the present invention described above.
- all are preferably 70 ° C. or higher, more preferably 72 ° C. or higher, further preferably 73 ° C. or higher, and 120 ° C. More preferably, it is 105 degrees C or less, More preferably, it is 99 degrees C or less.
- the surface temperature of each drying roll from the second drying roll to the drying roll X can obtain the above-described PVA film of the present invention more efficiently, it is 90 ° C. or lower, 85 ° C. or lower, and further 80 ° C. or lower. It may be.
- each drying roll from the drying roll located immediately after the drying roll X to the drying roll Y can improve the uniformity of drying while maintaining an appropriate drying temperature. It is preferable that both are 40 degreeC or more and less than 70 degreeC from the ability to obtain the PVA film of more efficiently, and the said surface temperature is more preferable that all are 45 degreeC or more, and 50 degreeC or more More preferably, it may be 55 ° C. or higher, more preferably 65 ° C. or lower, and further preferably 63 ° C. or lower.
- the PVA film dried by the drying roll is then heat treated by a plurality of heat treatment rolls.
- the PVA film immediately before being subjected to the heat treatment that is, the volatile content ratio of the PVA film immediately before contacting the heat treatment roll located on the most upstream side (heat treatment roll A) can effectively perform the heat treatment, etc. It is necessary that it is 3 mass% or more and 7 mass% or less, and it is preferable that the said volatile fraction is 4 mass% or more, and it is preferable that it is 6 mass% or less. Note that the volatile content of the PVA film may change during the heat treatment.
- the ratio (S B / S A ) of the peripheral speed (S B ) of the heat treatment roll B to the peripheral speed (S A ) of the heat treatment roll A is 0.999 or less. It is necessary to be. When the ratio (S B / S A ) exceeds 0.999, W MD30 of the obtained PVA film is lowered. Since the PVA film of the present invention can be obtained more efficiently, the ratio (S B / S A ) is preferably 0.995 or less, and more preferably 0.993 or less. In addition, from the viewpoint of effectively preventing wrinkles from being generated in the obtained PVA film, the ratio (S B / S A ) is preferably 0.985 or more, and 0.988 or more. More preferably.
- the surface temperature of each heat treatment roll from the heat treatment roll A to the heat treatment roll B must be 87 ° C. or more and 121 ° C. or less.
- the surface temperature is preferably 92 ° C. or higher, more preferably 93 ° C. or higher, and 119 ° C. or lower because the PVA film of the present invention can be obtained more efficiently.
- the temperature is preferably 117 ° C. or lower, more preferably 114 ° C. or lower.
- the surface temperatures of the heat treatment rolls from the heat treatment roll A to the heat treatment roll B may be the same or may be partially or entirely different from each other.
- the surface temperatures of the heat treatment roll A and the heat treatment roll B may be the same or different from each other, but the surface temperature of the heat treatment roll B should be 5 ° C. higher than the surface temperature of the heat treatment roll A. It is preferably 10 ° C. or higher, more preferably 12 ° C. or higher, even more preferably 15 ° C. or higher, particularly preferably 25 ° C. or lower, more preferably 20 ° C. or lower, more preferably 18 ° C. or higher. More preferably, the temperature is higher than or equal to ° C.
- the ratio (S B / S 1 ) of the peripheral speed (S B ) of the heat treatment roll B to the peripheral speed (S 1 ) of the first drying roll can obtain the above-described PVA film of the present invention more efficiently.
- the ratio (S B / S 1 ) is more preferably 0.920 or more, and further preferably 0.940 or more.
- it is 0.950 or more, more preferably 1.020 or less, still more preferably 1.010 or less, and particularly preferably 1.000 or less.
- the PVA film that has been heat-treated as described above can be subjected to a humidity control treatment, if necessary, and wound into a roll with a predetermined length to obtain the PVA film of the present invention.
- a humidity control treatment if necessary, and wound into a roll with a predetermined length to obtain the PVA film of the present invention.
- both ends (ears) in the width direction of the PVA film are cut and removed. May be.
- the volatile content of the PVA film finally obtained by the above-described series of treatments is preferably in the range of 1% by mass to 5% by mass, and the volatile content is more preferably 2% by mass or more. Moreover, it is more preferable that it is 4 mass% or less.
- the PVA film of this invention should be used as an original film at the time of manufacturing an optical film.
- the optical film include a polarizing film and a retardation film.
- the PVA film of the present invention since a thin polarizing film with reduced dyeing spots can be easily produced, the PVA film of the present invention is more preferably used as a raw film for producing a polarizing film. preferable.
- the optical film can be produced by a production method having a step of uniaxially stretching using the PVA film of the present invention. Specifically, the PVA film of the present invention itself or a swelling treatment described later is applied. PVA films derived from the PVA film of the present invention (hereinafter referred to as “PVA film of the present invention” and “PVA film derived from the PVA film of the present invention” collectively referred to as “PVA film based on the present invention”) Can be produced by a method having a step of uniaxial stretching.
- the method for producing a polarizing film using the PVA film of the present invention as a raw film is not particularly limited, and any conventionally employed method may be employed.
- a method for example, there is a method of dyeing and uniaxially stretching a PVA film based on the present invention, or uniaxially stretching a PVA film based on the present invention containing a dichroic dye.
- the PVA film based on the present invention is subjected to swelling, dyeing, uniaxial stretching, and further, if necessary, fixing treatment, drying treatment, heat treatment, etc. Is mentioned.
- the order of each treatment such as swelling, dyeing, uniaxial stretching, and fixing treatment is not particularly limited, and one or two or more treatments can be performed simultaneously. Also, one or more of each process can be performed twice or more.
- Swelling can be performed by immersing the PVA film according to the present invention in water.
- the temperature of the water when immersed in water is preferably within a range of 20 ° C. or higher and 40 ° C. or lower, more preferably 22 ° C. or higher, and further preferably 25 ° C. or higher. Moreover, it is more preferable that it is 38 degrees C or less, and it is still more preferable that it is 35 degrees C or less. Moreover, as time to immerse in water, it is preferable that it is 0.1 minute or more, for example, it is more preferable that it is 0.3 minute or more, and it is preferable that it is 5 minutes or less, It is 3 minutes or less. More preferably.
- the water at the time of immersing in water is not limited to pure water, The aqueous solution in which various components melt
- Dyeing can be performed by bringing a dichroic dye into contact with the PVA film according to the present invention.
- the dyeing time may be any stage before uniaxial stretching, during uniaxial stretching, or after uniaxial stretching.
- Dyeing is generally performed by immersing the PVA film in a solution (particularly an aqueous solution) containing iodine-potassium iodide which is a dyeing bath, and such a dyeing method is also suitably employed in the present invention.
- the concentration of iodine in the dyeing bath is preferably in the range of 0.01% by mass to 0.5% by mass, and the concentration of potassium iodide is in the range of 0.01% by mass to 10% by mass. Is preferred.
- the temperature of the dyeing bath is preferably 20 ° C. or more and 50 ° C. or less, and particularly preferably 25 ° C. or more and 40 ° C. or less.
- dichroic dye examples include iodine-based dyes and dichroic organic dyes (for example, 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; DirectViolet 9, 12, 51, 98; DirectGreen 1, 85 Direct Yellow 8, 12, 44, 86, 87; Direct Orange 26, 39, 106, 107, etc.), and iodine dyes are preferred.
- the iodine dye can be generated, for example, by bringing iodine (I 2 ) into contact with potassium iodide (KI).
- KI potassium iodide
- the uniaxial stretching of the PVA film according to the present invention may be performed by either a wet stretching method or a dry heat stretching method.
- a wet stretching method it can be carried out in an aqueous solution containing boric acid, or can be carried out in the dyeing bath described above or in a fixing treatment bath described later.
- the dry heat stretching method the PVA film after water absorption can be used in the air.
- the wet stretching method is preferable, and uniaxial stretching is more preferable in an aqueous solution containing boric acid.
- the concentration of boric acid in the boric acid aqueous solution is preferably in the range of 0.5% by mass or more and 6.0% by mass or less, and the concentration is more preferably 1.0% by mass or more.
- the content is more preferably at least mass%, more preferably at most 5.0 mass%, further preferably at most 4.0 mass%.
- the boric acid aqueous solution may contain potassium iodide, and the concentration of potassium iodide is preferably in the range of 0.01 mass% to 10 mass%.
- the stretching temperature in uniaxial stretching is not particularly limited, in the case of a wet stretching method, it is preferably within a range of 30 ° C. or higher and 90 ° C. or lower, and the stretching temperature is more preferably 40 ° C. or higher, and 45 ° C. More preferably, it is more preferably 70 ° C. or less, and further preferably 65 ° C. or less. In the case of the dry heat stretching method, it is preferably in the range of 50 ° C. or higher and 180 ° C. or lower.
- the stretching ratio in uniaxial stretching (the total stretching ratio obtained by multiplying the stretching ratios when performing uniaxial stretching in multiple stages) is preferably stretched as much as possible from the point of polarization performance until just before the film is cut. It is preferably 4 times or more, more preferably 5 times or more, and even more preferably 5.5 times or more.
- the upper limit of the draw ratio is not particularly limited as long as the film is not broken, but is preferably 8 times or less in order to perform uniform drawing.
- the draw ratio in this specification is based on the length of the film before extending
- the thickness of the stretched film (polarizing film) is preferably 25 ⁇ m or less, more preferably 23 ⁇ m or less, further preferably 20 ⁇ m or less, particularly preferably 18 ⁇ m or less, 15 ⁇ m or less, Furthermore, it may be 10 ⁇ m or less.
- the lower limit of the thickness of the stretched film (polarizing film) is not particularly limited, and may be, for example, 1 ⁇ m or more, 2 ⁇ m or more, 3 ⁇ m or more, and further 5 ⁇ m or more.
- uniaxial stretching in the length direction and uniaxial stretching in the lateral direction there is no particular limitation on the direction of uniaxial stretching, and uniaxial stretching in the length direction and uniaxial stretching in the lateral direction can be adopted. Since it is obtained, uniaxial stretching in the length direction is preferable. Uniaxial stretching in the length direction can be performed by changing the peripheral speed between the rolls using a stretching apparatus including a plurality of rolls parallel to each other. On the other hand, uniaxial stretching in the transverse direction can be performed using a tenter type stretching machine.
- the fixing treatment can be performed by immersing the film in a fixing treatment bath.
- a fixing treatment bath used for the fixing treatment an aqueous solution containing one or more of boron compounds such as boric acid and borax can be used.
- the concentration of the boron compound in the fixed treatment bath is generally preferably in the range of 2% by mass to 15% by mass, particularly preferably in the range of 3% by mass to 10% by mass.
- the temperature of the fixing treatment bath is preferably in the range of 15 ° C. or higher and 60 ° C. or lower, particularly in the range of 25 ° C. or higher and 40 ° C. or lower.
- the drying treatment is in the range of 30 ° C. or higher and 150 ° C. or lower, particularly in the range of 50 ° C. or higher and 140 ° C. or lower, in order to improve the dimensional stability of the obtained polarizing film and to suppress the decrease in polarizing performance It is preferable to carry out with.
- the polarizing film obtained as described above is usually used as a polarizing plate by laminating a protective film that is optically transparent and has mechanical strength on both sides or one side.
- a protective film a cellulose triacetate (TAC) film, a cycloolefin polymer (COP) film, an acetic acid / cellulose butyrate (CAB) film, an acrylic film, a polyester film, or the like is used.
- the adhesive for attaching the protective film include PVA adhesives, urethane adhesives, acrylate adhesives, etc. Among them, PVA adhesives are preferable.
- the polarizing plate obtained as described above can be used as an LCD component after being coated with an acrylic adhesive or the like and bonded to a glass substrate. At this time, a retardation film, a viewing angle improving film, a brightness improving film, and the like may be further bonded.
- the sample with the clip is quickly put into the pure water adjusted to 30 ° C stored in a cylindrical transparent water tank so that the entire sample enters the water.
- the long side was immersed vertically.
- a rod-shaped jig was hooked on the upper part of the water tank, and the long side of the sample was fixed so as to be vertical (vertical).
- a metal ruler was immersed in water, and the distance between the marked lines was measured 30 seconds after the immersion of the sample.
- the elongation (W MD30 ) (unit: mm) was calculated by subtracting the original distance between marked lines (250 mm) from the measured value read in 0.5 mm increments.
- the sample with the clip is quickly put into the pure water adjusted to 30 ° C stored in a cylindrical transparent water tank so that the entire sample enters the water.
- the long side was immersed vertically.
- a rod-shaped jig was hooked on the upper part of the water tank, and the long side of the sample was fixed so as to be vertical (vertical).
- a metal ruler was immersed in water, and the distance between marked lines was measured 300 seconds after the immersion of the sample.
- the amount of elongation (W TD300 ) (unit: mm) was calculated by subtracting the original distance between marked lines (250 mm) from the measured value read in 0.5 mm increments.
- PVA ethylene-modified PVA obtained by saponifying ethylene-modified polyvinyl acetate obtained by copolymerizing ethylene and vinyl acetate, ethylene unit content of 2.0 mol%, polymerization degree 2,400, saponification Degree of 99.9 mol%) 100 parts by mass, glycerin 10 parts by mass, lauric acid diethanolamide 0.1 parts by mass, and a volatile fraction of 66% by mass of a film-forming stock solution from the T-type slit die to each other with the rotation axis
- a first drying roll surface temperature 93.5 ° C., peripheral speed (S 1 ) 14.5 m / min) of a film forming apparatus including a plurality of parallel drying rolls and a plurality of heat treatment rolls is discharged into a film shape, While drying 90 ° C hot air at a wind speed of 5 m / second on the entire surface of the first drying roll non-contact on one drying roll, it is dried to
- the PVA membrane was further dried until its volatile content was 5% by mass.
- membrane becomes 12 mass% is a 5th drying roll, and surface temperature of each drying roll from a 2nd drying roll to a 5th drying roll is set.
- the surface temperature of each drying roll after the sixth drying roll was set to 60 ° C.
- the PVA film was subjected to heat treatment with a plurality of heat treatment rolls while the front and back surfaces of the PVA film were alternately opposed to each heat treatment roll.
- the ratio of the peripheral speed (S B ) of the heat treatment roll (heat treatment roll B) located on the most downstream side to the peripheral speed (S A ) of the heat treatment roll (heat treatment roll A) located on the most upstream side (S B / S A ) is 0.991, and the surface temperature of each heat treatment roll is 99 to 115 ° C. (the surface temperature of heat treatment roll A is 99 ° C., the surface temperature of heat treatment roll B is 115 ° C.).
- the ratio (S B / S 1 ) of the peripheral speed (S B ) of the heat treatment roll B to the peripheral speed (S 1 ) of the first drying roll was 0.965.
- the PVA film obtained above was unwound from a roll and slit to continuously cut out a portion having a width of 650 mm from the central portion in the width direction, and then subjected to each treatment to continuously produce a polarizing film.
- the PVA film was immersed in a swelling bath (water temperature 30 ° C.), followed by a dyeing bath (water temperature 32 ° C., an aqueous solution containing 0.07 mass% iodine and 1.6 mass% potassium iodide), Fixed treatment bath (water temperature 32 ° C., aqueous solution containing 2.6% by mass of boric acid), stretching bath (water temperature 58 ° C., aqueous solution containing 2.8% by mass of boric acid and 5.0% by mass of potassium iodide)
- the film is immersed in a washing bath (water temperature 22 ° C., aqueous solution containing 1.5% by mass of boric acid and 5.0% by mass of potassium iodide) and dried in a drying furnace (temperature 40 ° C.) to obtain a polarizing film.
- Examples 2 and 3 and Comparative Examples 1 to 3 A PVA film was produced in the same manner as in Example 1 except that the production conditions of the PVA film were as shown in Table 1, and a polarizing film was produced in the same manner as in Example 1. Each evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.
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Abstract
Description
[1]厚みが50μm以下のPVAフィルムであって、当該PVAフィルムのサンプルを30℃の水に30秒間浸漬したときの浸漬前の長さ方向250mmの部分における長さ方向の伸び量WMD30が35mm以上60mm以下であり、当該PVAフィルムのサンプルを30℃の水に300秒間浸漬したときの浸漬前の幅方向250mmの部分における幅方向の伸び量WTD300が53mm以上65mm以下である、PVAフィルム;
[2]幅が2m以上である、上記[1]のPVAフィルム;
[3]光学フィルム製造用原反フィルムである、上記[1]または[2]のPVAフィルム;
[4]光学フィルムが偏光フィルムである、上記[3]のPVAフィルム;
[5]厚みが50μm以下のPVAフィルムの製造方法であって、回転軸が互いに平行な乾燥ロールと熱処理ロールを備える製膜装置を使用し、当該製膜装置の第1乾燥ロール上にPVAを含む製膜原液を膜状に吐出して乾燥し、それに続く乾燥ロールで更に乾燥し、その後、複数の熱処理ロールで熱処理してPVAフィルムを製造し、ここで、最上流側に位置する熱処理ロールを熱処理ロールAとし、最下流側に位置する熱処理ロールを熱処理ロールBとした際に、熱処理ロールAに接触する直前のPVA膜の揮発分率が3質量%以上7質量%以下であり、熱処理ロールAの周速(SA)に対する熱処理ロールBの周速(SB)の比(SB/SA)が0.999以下であり、熱処理ロールAから熱処理ロールBまでの各熱処理ロールの表面温度がいずれも87℃以上121℃以下である、製造方法;
[6]PVA膜の揮発分率が12質量%になったときの乾燥ロールを乾燥ロールXとし、熱処理ロールAの直前に位置する乾燥ロールを乾燥ロールYとした際に、第1乾燥ロールから乾燥ロールXまでの各乾燥ロールの表面温度がいずれも70℃以上であり、乾燥ロールXの直後に位置する乾燥ロールから乾燥ロールYまでの各乾燥ロールの表面温度がいずれも40℃以上70℃未満である、上記[5]の製造方法;
[7]第1乾燥ロールの周速(S1)に対する熱処理ロールBの周速(SB)の比(SB/S1)が0.900以上1.050以下である、上記[5]または[6]の製造方法;
[8]熱処理ロールAの直前に位置する乾燥ロールを乾燥ロールYとした際に、第1乾燥ロールから乾燥ロールYまでの間において、各乾燥ロールに対してPVA膜の表裏両面を交互に対向させる、上記[5]~[7]のいずれか1つの製造方法;
[9]光学フィルム製造用原反フィルムの製造方法である、上記[5]~[8]のいずれか1つの製造方法;
[10]光学フィルムが偏光フィルムである、上記[9]の製造方法;
[11]上記[3]のPVAフィルムから製造した光学フィルム;
[12]上記[4]のPVAフィルムから製造した偏光フィルム;
に関する。 That is, the present invention
[1] A PVA film having a thickness of 50 μm or less, and when the sample of the PVA film is immersed in water at 30 ° C. for 30 seconds, an elongation amount W MD30 in a length direction in a portion having a length direction of 250 mm before immersion is A PVA film that is 35 mm or more and 60 mm or less, and has a width direction extension amount W TD300 of 53 mm or more and 65 mm or less in a 250 mm width portion before immersion when the PVA film sample is immersed in water at 30 ° C. for 300 seconds. ;
[2] The PVA film of the above [1], having a width of 2 m or more;
[3] The PVA film of the above [1] or [2], which is a raw film for producing an optical film;
[4] The PVA film of the above [3], wherein the optical film is a polarizing film;
[5] A method for producing a PVA film having a thickness of 50 μm or less, wherein a film forming apparatus including a drying roll and a heat treatment roll having rotation axes parallel to each other is used, and PVA is applied to the first drying roll of the film forming apparatus. The film-forming stock solution is discharged in a film form and dried, followed by further drying with a drying roll, and then heat treatment with a plurality of heat treatment rolls to produce a PVA film, where the heat treatment roll located on the most upstream side Is the heat treatment roll A, and the heat treatment roll located on the most downstream side is the heat treatment roll B, the volatile fraction of the PVA film immediately before contacting the heat treatment roll A is 3% by mass or more and 7% by mass or less. peripheral speed peripheral speed of the heat treatment roll B to (S a) of the roll a ratio (S B) (S B / S a) is 0.999 or less, from the heat treatment roll a to the heat treatment roll B of the heat treatment roll A production method wherein the surface temperature is 87 ° C. or higher and 121 ° C. or lower;
[6] When the drying roll when the volatile content ratio of the PVA film is 12% by mass is the drying roll X and the drying roll located immediately before the heat treatment roll A is the drying roll Y, the first drying roll The surface temperature of each drying roll up to the drying roll X is 70 ° C. or more, and the surface temperature of each drying roll from the drying roll located immediately after the drying roll X to the drying roll Y is 40 ° C. or more and 70 ° C. The production method of the above-mentioned [5], which is less than
[7] The above [5], wherein the ratio (S B / S 1 ) of the peripheral speed (S B ) of the heat treatment roll B to the peripheral speed (S 1 ) of the first drying roll is 0.900 or more and 1.050 or less. Or the production method of [6];
[8] When the drying roll located immediately before the heat treatment roll A is the drying roll Y, the front and back surfaces of the PVA film are alternately opposed to each drying roll between the first drying roll and the drying roll Y. Any one of the production methods of [5] to [7] above;
[9] The method for producing any one of the above [5] to [8], which is a method for producing an original film for producing an optical film;
[10] The method according to [9] above, wherein the optical film is a polarizing film;
[11] An optical film produced from the PVA film of [3] above;
[12] A polarizing film produced from the PVA film of [4] above;
About.
〔PVAフィルム〕
本発明のPVAフィルムは厚みが50μm以下である。そして本発明のPVAフィルムは、そのサンプルを30℃の水に30秒間浸漬したときの浸漬前の長さ方向250mmの部分における長さ方向の伸び量WMD30が35mm以上60mm以下である。さらに本発明のPVAフィルムは、そのサンプルを30℃の水に300秒間浸漬したときの浸漬前の幅方向250mmの部分における幅方向の伸び量WTD300が53mmを超え65mm以下である。 The present invention is described in detail below.
[PVA film]
The PVA film of the present invention has a thickness of 50 μm or less. And as for the PVA film of this invention, when the sample is immersed in 30 degreeC water for 30 second, elongation amount WMD30 of the length direction in the part of the length direction 250mm before immersion is 35 mm or more and 60 mm or less. Furthermore, in the PVA film of the present invention, when the sample is immersed in water at 30 ° C. for 300 seconds, the amount of elongation WTD300 in the width direction in the portion in the width direction 250 mm before immersion is more than 53 mm and not more than 65 mm.
本発明のPVAフィルムの製法は特に限定されないが、以下の本発明の製造方法によれば、本発明のPVAフィルムを生産性よく円滑に連続して製造することができる。 [Production method of PVA film]
Although the manufacturing method of the PVA film of this invention is not specifically limited, According to the manufacturing method of the following this invention, the PVA film of this invention can be manufactured smoothly with sufficient productivity.
製膜原液の揮発分率(質量%)= 100×(Wa-Wb)/Wa (1)
(ここで、Waは製膜原液の質量(g)を表し、WbはWa(g)の製膜原液を105℃の電熱乾燥機中で16時間乾燥した時の質量(g)を表す。) The volatile fraction of the film-forming stock solution is preferably in the range of 50% by mass or more and 90% by mass or less, and the volatile fraction is more preferably 55% by mass or more and 80% by mass or less. It is more preferable. If the volatile content is too low, the viscosity of the film-forming stock solution may become too high, making film formation difficult. On the other hand, if the volatile content is too high, the uniformity of the thickness of the obtained PVA film may be impaired. In addition, “the volatile matter rate of the film-forming stock solution” in this specification refers to the volatile matter rate obtained by the following formula (1).
Volatile fraction (mass%) of the film-forming stock solution = 100 × (W a −W b ) / W a (1)
(Where, W a represents a film-forming stock solution mass (g), W b is W a (g) mass when a film-forming solution was dried 16 hours in a 105 ° C. of the heating dryer of (g) To express.)
ここで、本明細書における「PVA膜の揮発分率」とは、下記式(2)により求めた揮発分率をいう。
PVA膜の揮発分率(質量%) = 100 × (Wc-Wd)/Wc} (2)
(ここで、WcはPVA膜から採取したサンプルの質量(g)を表し、Wdは前記サンプルWc(g)を温度50℃、圧力0.1kPa以下の真空乾燥機中に入れて4時間乾燥した時の質量(g)を示す。) 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 peeled off from the first drying roll. If the volatile content of the PVA film at the time of peeling from the first drying roll is too low, the productivity of the PVA film tends to decrease, while the volatile content of the PVA film at the time of peeling from the first drying roll. If the rate is too high, peeling from the first drying roll is likely to be difficult, and in some cases, breakage or spots are likely to occur. From the above viewpoint, the volatile fraction of the PVA film at the time of peeling from the first drying roll is preferably 13% by mass or more, more preferably 14% by mass or more, and 15% by mass or more. More preferably, it is preferably 30% by mass or less, more preferably 27% by mass or less, and further preferably 25% by mass or less.
Here, “the volatile content of the PVA film” in this specification refers to the volatile content determined by the following formula (2).
Volatile content (% by mass) of PVA film = 100 × (W c −W d ) / W c } (2)
(Here, W c represents the mass (g) of the sample taken from PVA film, W d is placed in the sample W c (g) of temperature 50 ° C., a pressure 0.1kPa following vacuum dryer 4 (The mass (g) when dried for hours is shown.)
本発明のPVAフィルムの用途に特に制限はないが、延伸性に優れると共に、使用時に端部異常が生じにくいことから、本発明のPVAフィルムは光学フィルムを製造する際の原反フィルムとして用いることが好ましい。光学フィルムとしては、偏光フィルム、位相差フィルムなどが挙げられる。特に本発明のPVAフィルムによれば染色斑が低減された薄型の偏光フィルムを容易に製造することができることから、本発明のPVAフィルムは偏光フィルムを製造する際の原反フィルムとして用いることがより好ましい。 [Use of PVA film]
Although there is no restriction | limiting in particular in the use of the PVA film of this invention, since it is excellent in extending | stretching and an end part abnormality does not arise easily at the time of use, the PVA film of this invention should be used as an original film at the time of manufacturing an optical film. Is preferred. Examples of the optical film include a polarizing film and a retardation film. In particular, according to the PVA film of the present invention, since a thin polarizing film with reduced dyeing spots can be easily produced, the PVA film of the present invention is more preferably used as a raw film for producing a polarizing film. preferable.
PVAフィルムの幅方向中央部から幅方向(TD)40mm×長さ方向(MD)270mmの矩形のサンプルを切り出した。次に、当該サンプルの270mm長の両端から10mmずつ内側に油性マジック(線の太さが0.3mm)で標線を入れた。両端の標線から外側の部分を市販のクリップ(チャック幅40mm、質量7.8g(水中での重量7.3g))で挟み、一方のクリップは棒状冶具で固定した。標線間距離が250mmであることを確認後、円筒状の透明な水槽に蓄えた30℃に調温した純水に、クリップが付いたサンプルをサンプル全体が水中に入るように、速やかにサンプル長辺を垂直(鉛直)に浸漬した。浸漬直後に水槽上部に棒状冶具を引っ掛けてサンプル長辺を垂直(鉛直)になるように固定した。その後、金属製の物差しを水中に浸漬して、サンプルの浸漬から30秒後に標線間距離を測定した。0.5mm刻みで読み取った当該測定値から元の標線間距離(250mm)を引いて伸び量(WMD30)(単位はmm)を算出した。 [Measurement of W MD30 ]
A rectangular sample having a width direction (TD) of 40 mm × a length direction (MD) of 270 mm was cut out from the center in the width direction of the PVA film. Next, a marked line was put with oily magic (the thickness of the line was 0.3 mm) on the inner side by 10 mm from both ends of the 270 mm length of the sample. The outer part from the marked lines at both ends was sandwiched between commercially available clips (chuck width 40 mm, mass 7.8 g (weight 7.3 g in water)), and one clip was fixed with a rod-shaped jig. After confirming that the distance between the marked lines is 250 mm, the sample with the clip is quickly put into the pure water adjusted to 30 ° C stored in a cylindrical transparent water tank so that the entire sample enters the water. The long side was immersed vertically. Immediately after the immersion, a rod-shaped jig was hooked on the upper part of the water tank, and the long side of the sample was fixed so as to be vertical (vertical). Thereafter, a metal ruler was immersed in water, and the distance between the marked lines was measured 30 seconds after the immersion of the sample. The elongation (W MD30 ) (unit: mm) was calculated by subtracting the original distance between marked lines (250 mm) from the measured value read in 0.5 mm increments.
PVAフィルムの幅方向中央部から幅方向(TD)270mm×長さ方向(MD)40mmの矩形のサンプルを切り出した。次に、当該サンプルの270mm長の両端から10mmずつ内側に油性マジック(線の太さが0.3mm)で標線を入れた。両端の標線から外側の部分を市販のクリップ(チャック幅40mm、質量7.8g(水中での重量7.3g))で挟み、一方のクリップは棒状冶具で固定した。標線間距離が250mmであることを確認後、円筒状の透明な水槽に蓄えた30℃に調温した純水に、クリップが付いたサンプルをサンプル全体が水中に入るように、速やかにサンプル長辺を垂直(鉛直)に浸漬した。浸漬直後に水槽上部に棒状冶具を引っ掛けてサンプル長辺を垂直(鉛直)になるように固定した。その後、金属製の物差しを水中に浸漬して、サンプルの浸漬から300秒後に標線間距離を測定した。0.5mm刻みで読み取った当該測定値から元の標線間距離(250mm)を引いて伸び量(WTD300)(単位はmm)を算出した。 [Measurement of WTD300 ]
A rectangular sample having a width direction (TD) of 270 mm and a length direction (MD) of 40 mm was cut out from the center in the width direction of the PVA film. Next, a marked line was put with oily magic (the thickness of the line was 0.3 mm) on the inner side by 10 mm from both ends of the 270 mm length of the sample. The outer part from the marked lines at both ends was sandwiched between commercially available clips (chuck width 40 mm, mass 7.8 g (weight 7.3 g in water)), and one clip was fixed with a rod-shaped jig. After confirming that the distance between the marked lines is 250 mm, the sample with the clip is quickly put into the pure water adjusted to 30 ° C stored in a cylindrical transparent water tank so that the entire sample enters the water. The long side was immersed vertically. Immediately after the immersion, a rod-shaped jig was hooked on the upper part of the water tank, and the long side of the sample was fixed so as to be vertical (vertical). Thereafter, a metal ruler was immersed in water, and the distance between marked lines was measured 300 seconds after the immersion of the sample. The amount of elongation (W TD300 ) (unit: mm) was calculated by subtracting the original distance between marked lines (250 mm) from the measured value read in 0.5 mm increments.
PVAフィルムの延伸性の指標として、延伸浴における延伸時の張力を測定し、以下の基準に従って延伸性を評価した。
◎:10MPa以上12MPa以下
○:12MPaを超え15MPa以下
△:15MPaを超え18MPa以下
×:10MPa未満または18MPaを超える [Evaluation of stretchability of PVA film]
As an index of the stretchability of the PVA film, the tension during stretching in the stretching bath was measured, and the stretchability was evaluated according to the following criteria.
◎: 10 MPa or more and 12 MPa or less ○: More than 12 MPa and 15 MPa or less Δ: More than 15 MPa and 18 MPa or less ×: Less than 10 MPa or more than 18 MPa
膨潤浴を通過した直後のロールにおけるフィルムの端部異常を、以下の基準に従って評価した。
○:端部異常が全く確認できない
△:端部異常がわずかに確認できる
×:端部異常がはっきり確認できる [Evaluation of edge abnormalities]
The abnormal end of the film in the roll immediately after passing through the swelling bath was evaluated according to the following criteria.
○: Edge abnormalities cannot be confirmed at all △: Edge abnormalities can be slightly confirmed ×: Edge abnormalities can be clearly confirmed
クロスニコル状態の2枚の偏光板(単体透過率42.3%、偏光度99.99%)の間に作製した偏光フィルムを挟んだ後、暗室にて、輝度10,000cd/m2のライトボックスを用いて光を透過させた時の染色斑を観察し、以下の基準に従って評価した。
◎:染色斑が全く確認できない
○:染色斑がわずかに確認できる
△:染色斑が比較的明瞭に確認できる
×:染色斑がはっきりと確認できる [Evaluation of stained spots on polarizing film]
A light having a luminance of 10,000 cd / m 2 in a dark room after sandwiching the produced polarizing film between two polarizing plates in a crossed Nicol state (single transmittance 42.3%, polarization degree 99.99%) The stained spots when light was transmitted using a box were observed and evaluated according to the following criteria.
◎: Stained spots cannot be confirmed at all ○: Stained spots can be confirmed slightly △: Stained spots can be confirmed relatively clearly ×: Stained spots can be confirmed clearly
《PVAフィルムの製造》
PVA(エチレンと酢酸ビニルを共重合することにより得られたエチレン変性ポリ酢酸ビニルをけん化することにより得られたエチレン変性PVA、エチレン単位の含有率2.0モル%、重合度2,400、けん化度99.9モル%)100質量部、グリセリン10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、T型スリットダイから回転軸が互いに平行な複数の乾燥ロールと複数の熱処理ロールを備える製膜装置の第1乾燥ロール(表面温度93.5℃、周速(S1)14.5m/分)上に膜状に吐出し、第1乾燥ロール上で、第1乾燥ロール非接触面の全体に90℃の熱風を5m/秒の風速で吹きつけながら揮発分率15質量%になるまで乾燥し、第1乾燥ロールから剥離した。
次いで、PVA膜の第1乾燥ロール非接触面が第2乾燥ロールに対向するようにして各乾燥ロールに対してPVA膜の表裏両面を交互に対向させながら、第2乾燥ロール以降の乾燥ロールでPVA膜をその揮発分率が5質量%になるまでさらに乾燥した。なお、PVA膜の揮発分率が12質量%になったときの乾燥ロール(乾燥ロールX)は第5乾燥ロールであり、第2乾燥ロールから第5乾燥ロールまでの各乾燥ロールの表面温度を75℃とし、第6乾燥ロール以降の各乾燥ロールの表面温度を60℃とした。
その後、各熱処理ロールに対してPVA膜の表裏両面を交互に対向させながら、複数の熱処理ロールでPVA膜に熱処理を施した。この際に、最上流側に位置する熱処理ロール(熱処理ロールA)の周速(SA)に対する最下流側に位置する熱処理ロール(熱処理ロールB)の周速(SB)の比(SB/SA)を0.991とし、各熱処理ロールの表面温度を99~115℃とした(熱処理ロールAの表面温度99℃、熱処理ロールBの表面温度115℃)。第1乾燥ロールの周速(S1)に対する熱処理ロールBの周速(SB)の比(SB/S1)は0.965であった。
上記のようにして熱処理を施した後、巻き取って、ロール状のPVAフィルム(厚み45μm、幅3m、長さ5,000m、揮発分率3質量%)を得た。
得られたPVAフィルムについて、上記した方法にしたがってWMD30およびWTD300を測定した。結果を表1に示した。 [Example 1]
<< Manufacture of PVA film >>
PVA (ethylene-modified PVA obtained by saponifying ethylene-modified polyvinyl acetate obtained by copolymerizing ethylene and vinyl acetate, ethylene unit content of 2.0 mol%, polymerization degree 2,400, saponification Degree of 99.9 mol%) 100 parts by mass, glycerin 10 parts by mass, lauric acid diethanolamide 0.1 parts by mass, and a volatile fraction of 66% by mass of a film-forming stock solution from the T-type slit die to each other with the rotation axis A first drying roll (surface temperature 93.5 ° C., peripheral speed (S 1 ) 14.5 m / min) of a film forming apparatus including a plurality of parallel drying rolls and a plurality of heat treatment rolls is discharged into a film shape, While drying 90 ° C hot air at a wind speed of 5 m / second on the entire surface of the first drying roll non-contact on one drying roll, it is dried to a volatile content of 15% by mass and peeled off from the first drying roll. .
Next, with the first drying roll non-contact surface of the PVA film facing the second drying roll, while the front and back surfaces of the PVA film are alternately opposed to each drying roll, The PVA membrane was further dried until its volatile content was 5% by mass. In addition, the drying roll (drying roll X) when the volatile content rate of a PVA film | membrane becomes 12 mass% is a 5th drying roll, and surface temperature of each drying roll from a 2nd drying roll to a 5th drying roll is set. The surface temperature of each drying roll after the sixth drying roll was set to 60 ° C.
Thereafter, the PVA film was subjected to heat treatment with a plurality of heat treatment rolls while the front and back surfaces of the PVA film were alternately opposed to each heat treatment roll. At this time, the ratio of the peripheral speed (S B ) of the heat treatment roll (heat treatment roll B) located on the most downstream side to the peripheral speed (S A ) of the heat treatment roll (heat treatment roll A) located on the most upstream side (S B / S A ) is 0.991, and the surface temperature of each heat treatment roll is 99 to 115 ° C. (the surface temperature of heat treatment roll A is 99 ° C., the surface temperature of heat treatment roll B is 115 ° C.). The ratio (S B / S 1 ) of the peripheral speed (S B ) of the heat treatment roll B to the peripheral speed (S 1 ) of the first drying roll was 0.965.
After heat-treating as described above, it was wound up to obtain a roll-like PVA film (thickness 45 μm, width 3 m, length 5,000 m, volatile content 3 mass%).
About the obtained PVA film, WMD30 and WTD300 were measured according to the above-mentioned method. The results are shown in Table 1.
上記で得られたPVAフィルムをロールから巻き出し、スリットして幅方向中央部から幅650mmの部分を連続的に切り出し、次いで、各処理を施して偏光フィルムを連続的に製造した。
すなわち、PVAフィルムを、膨潤浴(水温30℃)中に浸漬し、続いて、染色浴(水温32℃、ヨウ素を0.07質量%およびヨウ化カリウムを1.6質量%含有する水溶液)、固定処理浴(水温32℃、ホウ酸を2.6質量%含有する水溶液)、延伸浴(水温58℃、ホウ酸を2.8質量%およびヨウ化カリウムを5.0質量%含有する水溶液)、洗浄浴(水温22℃、ホウ酸を1.5質量%およびヨウ化カリウムを5.0質量%含有する水溶液)に順次浸漬し、さらに乾燥炉(温度40℃)で乾燥して偏光フィルムを製造した。なお、膨潤浴に浸漬する時間としては、薄型のPVAフィルムに対応させるため、比較的短い40秒間を採用した。また、総延伸倍率は6.3倍とした。
当該偏光フィルムの製造において、上記した方法にしたがって使用したPVAフィルムの延伸性を評価すると共に端部異常の評価を行った。また得られた偏光フィルムについて、上記した方法にしたがって染色斑を評価した。結果を表1に示した。 <Manufacture of polarizing film>
The PVA film obtained above was unwound from a roll and slit to continuously cut out a portion having a width of 650 mm from the central portion in the width direction, and then subjected to each treatment to continuously produce a polarizing film.
That is, the PVA film was immersed in a swelling bath (water temperature 30 ° C.), followed by a dyeing bath (water temperature 32 ° C., an aqueous solution containing 0.07 mass% iodine and 1.6 mass% potassium iodide), Fixed treatment bath (water temperature 32 ° C., aqueous solution containing 2.6% by mass of boric acid), stretching bath (water temperature 58 ° C., aqueous solution containing 2.8% by mass of boric acid and 5.0% by mass of potassium iodide) The film is immersed in a washing bath (water temperature 22 ° C., aqueous solution containing 1.5% by mass of boric acid and 5.0% by mass of potassium iodide) and dried in a drying furnace (temperature 40 ° C.) to obtain a polarizing film. Manufactured. In addition, as time to immerse in a swelling bath, in order to respond | correspond to a thin PVA film, the comparatively short 40 second was employ | adopted. The total draw ratio was 6.3 times.
In manufacture of the said polarizing film, while extending | stretching the PVA film used according to the above-mentioned method, evaluation of edge part abnormality was performed. Further, the obtained polarizing film was evaluated for stained spots according to the method described above. The results are shown in Table 1.
PVAフィルムの製造条件を表1のようにしたこと以外は実施例1と同様にしてPVAフィルムを製造するとともに実施例1と同様にして偏光フィルムを製造した。そして、実施例1と同様にして各評価を行った。結果を表1に示した。 << Examples 2 and 3 and Comparative Examples 1 to 3 >>
A PVA film was produced in the same manner as in Example 1 except that the production conditions of the PVA film were as shown in Table 1, and a polarizing film was produced in the same manner as in Example 1. Each evaluation was performed in the same manner as in Example 1. The results are shown in Table 1.
Claims (12)
- 厚みが50μm以下のポリビニルアルコール系重合体フィルムであって、当該ポリビニルアルコール系重合体フィルムのサンプルを30℃の水に30秒間浸漬したときの浸漬前の長さ方向250mmの部分における長さ方向の伸び量WMD30が35mm以上60mm以下であり、当該ポリビニルアルコール系重合体フィルムのサンプルを30℃の水に300秒間浸漬したときの浸漬前の幅方向250mmの部分における幅方向の伸び量WTD300が53mm以上65mm以下である、ポリビニルアルコール系重合体フィルム。 A polyvinyl alcohol polymer film having a thickness of 50 μm or less, and a sample of the polyvinyl alcohol polymer film in the length direction at a portion of 250 mm in the length direction before immersion when immersed in water at 30 ° C. for 30 seconds. Elongation amount W MD30 is 35 mm or more and 60 mm or less, and when the sample of the polyvinyl alcohol polymer film is immersed in water at 30 ° C. for 300 seconds, the elongation amount W TD300 in the width direction in the width direction 250 mm portion before immersion is A polyvinyl alcohol polymer film having a thickness of 53 mm or more and 65 mm or less.
- 幅が2m以上である、請求項1に記載のポリビニルアルコール系重合体フィルム。 The polyvinyl alcohol polymer film according to claim 1, wherein the width is 2 m or more.
- 光学フィルム製造用原反フィルムである、請求項1または2に記載のポリビニルアルコール系重合体フィルム。 The polyvinyl alcohol polymer film according to claim 1 or 2, which is a raw film for producing an optical film.
- 光学フィルムが偏光フィルムである、請求項3に記載のポリビニルアルコール系重合体フィルム。 The polyvinyl alcohol polymer film according to claim 3, wherein the optical film is a polarizing film.
- 厚みが50μm以下のポリビニルアルコール系重合体フィルムの製造方法であって、回転軸が互いに平行な乾燥ロールと熱処理ロールを備える製膜装置を使用し、当該製膜装置の第1乾燥ロール上にポリビニルアルコール系重合体を含む製膜原液を膜状に吐出して乾燥し、それに続く乾燥ロールで更に乾燥し、その後、複数の熱処理ロールで熱処理してポリビニルアルコール系重合体フィルムを製造し、ここで、最上流側に位置する熱処理ロールを熱処理ロールAとし、最下流側に位置する熱処理ロールを熱処理ロールBとした際に、熱処理ロールAに接触する直前のポリビニルアルコール系重合体膜の揮発分率が3質量%以上7質量%以下であり、熱処理ロールAの周速(SA)に対する熱処理ロールBの周速(SB)の比(SB/SA)が0.999以下であり、熱処理ロールAから熱処理ロールBまでの各熱処理ロールの表面温度がいずれも87℃以上121℃以下である、製造方法。 A method for producing a polyvinyl alcohol polymer film having a thickness of 50 μm or less, wherein a film forming apparatus comprising a drying roll and a heat treatment roll having rotation axes parallel to each other is used, and polyvinyl on the first drying roll of the film forming apparatus A film-forming stock solution containing an alcohol polymer is discharged into a film and dried, followed by further drying with a drying roll, and then heat treatment with a plurality of heat treatment rolls to produce a polyvinyl alcohol polymer film, where When the heat treatment roll located on the most upstream side is the heat treatment roll A and the heat treatment roll located on the most downstream side is the heat treatment roll B, the volatile fraction of the polyvinyl alcohol polymer film immediately before contacting the heat treatment roll A There is at most 3 mass% or more and 7 wt%, the ratio (S B / S of the peripheral speed of the heat treatment roll a peripheral speed of the heat treatment roll B to (S a) (S B) ) Is 0.999 or less, the surface temperature of each heat treatment roll from the heated rollers A to the heat treatment roll B is 121 ° C. or less all of which are 87 ° C., the manufacturing method.
- ポリビニルアルコール系重合体膜の揮発分率が12質量%になったときの乾燥ロールを乾燥ロールXとし、熱処理ロールAの直前に位置する乾燥ロールを乾燥ロールYとした際に、第1乾燥ロールから乾燥ロールXまでの各乾燥ロールの表面温度がいずれも70℃以上であり、乾燥ロールXの直後に位置する乾燥ロールから乾燥ロールYまでの各乾燥ロールの表面温度がいずれも40℃以上70℃未満である、請求項5に記載の製造方法。 When the drying roll when the volatile fraction of the polyvinyl alcohol polymer film is 12% by mass is the drying roll X and the drying roll located immediately before the heat treatment roll A is the drying roll Y, the first drying roll The surface temperature of each drying roll from the drying roll X to the drying roll X is 70 ° C. or more, and the surface temperature of each drying roll from the drying roll located immediately after the drying roll X to the drying roll Y is 40 ° C. to 70 ° C. The manufacturing method of Claim 5 which is less than degreeC.
- 第1乾燥ロールの周速(S1)に対する熱処理ロールBの周速(SB)の比(SB/S1)が0.900以上1.050以下である、請求項5または6に記載の製造方法。 The ratio (S B / S 1 ) of the peripheral speed (S B ) of the heat treatment roll B to the peripheral speed (S 1 ) of the first drying roll is 0.900 or more and 1.050 or less. Manufacturing method.
- 熱処理ロールAの直前に位置する乾燥ロールを乾燥ロールYとした際に、第1乾燥ロールから乾燥ロールYまでの間において、各乾燥ロールに対してポリビニルアルコール系重合体膜の表裏両面を交互に対向させる、請求項5~7のいずれか1項に記載の製造方法。 When the drying roll located immediately before the heat treatment roll A is the drying roll Y, between the first drying roll and the drying roll Y, the front and back surfaces of the polyvinyl alcohol polymer film are alternately placed on each drying roll. The production method according to any one of claims 5 to 7, which is opposed to each other.
- 光学フィルム製造用原反フィルムの製造方法である、請求項5~8のいずれか1項に記載の製造方法。 The production method according to any one of claims 5 to 8, which is a production method of a raw film for producing an optical film.
- 光学フィルムが偏光フィルムである、請求項9に記載の製造方法。 The manufacturing method according to claim 9, wherein the optical film is a polarizing film.
- 請求項3に記載のポリビニルアルコール系重合体フィルムから製造した光学フィルム。 An optical film produced from the polyvinyl alcohol polymer film according to claim 3.
- 請求項4に記載のポリビニルアルコール系重合体フィルムから製造した偏光フィルム。
A polarizing film produced from the polyvinyl alcohol polymer film according to claim 4.
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WO2018199140A1 (en) * | 2017-04-26 | 2018-11-01 | 日本合成化学工業株式会社 | Polyvinyl alcohol film, polarizing film and polarizing plate, and polyvinyl alcohol film production method |
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