WO2021070622A1 - Film pour la production d'un film optique, procédé de production d'un film optique, et film optique - Google Patents

Film pour la production d'un film optique, procédé de production d'un film optique, et film optique Download PDF

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Publication number
WO2021070622A1
WO2021070622A1 PCT/JP2020/036028 JP2020036028W WO2021070622A1 WO 2021070622 A1 WO2021070622 A1 WO 2021070622A1 JP 2020036028 W JP2020036028 W JP 2020036028W WO 2021070622 A1 WO2021070622 A1 WO 2021070622A1
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Prior art keywords
film
optical film
group
pva
producing
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PCT/JP2020/036028
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English (en)
Japanese (ja)
Inventor
さやか 清水
喬士 練苧
慎二 中井
匡希 中谷
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株式会社クラレ
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Priority to KR1020227007705A priority Critical patent/KR20220074860A/ko
Priority to CN202080070727.0A priority patent/CN114450329A/zh
Priority to JP2021551156A priority patent/JPWO2021070622A1/ja
Publication of WO2021070622A1 publication Critical patent/WO2021070622A1/fr

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Classifications

    • 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
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/18—Manufacture of films or sheets
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F216/00—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
    • C08F216/02—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 by an alcohol radical
    • C08F216/04—Acyclic compounds
    • C08F216/06—Polyvinyl alcohol ; Vinyl alcohol
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • 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
    • G02B5/3041—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 comprising multiple thin layers, e.g. multilayer stacks
    • G02B5/305—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 comprising multiple thin layers, e.g. multilayer stacks including organic materials, e.g. polymeric layers
    • 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 film for producing an optical film, a method for producing an optical film, and an optical film.
  • a polarizing plate having a function of transmitting and shielding light is a basic component of a liquid crystal display (LCD) together with a liquid crystal that changes the polarization state of light.
  • LCD liquid crystal display
  • Many polarizing plates have a structure in which a protective film such as a cellulose triacetate (TAC) film is bonded to the surface of a polarizing film.
  • TAC cellulose triacetate
  • the polarizing film a polyvinyl alcohol film (hereinafter, the "polyvinyl alcohol” may be abbreviated as "PVA”.)
  • Matrix produced by uniaxially stretching a (stretched film) to iodine dye (I 3 - and I 5 - Etc.) and dichroic dyes such as dichroic organic dyes are mainly adsorbed.
  • LCDs are widely used in small devices such as calculators and wristwatches, smartphones, laptop computers, LCD monitors, LCD color projectors, LCD TVs, in-vehicle navigation systems, mobile phones, and measuring devices used indoors and outdoors. In recent years, these devices have been required to improve display quality.
  • the polarizing film is also required to have high performance, and specifically, a polarizing film having excellent optical performance such as polarization degree and transmittance is required. Durability is also important for polarizing films, and it is required that good performance be maintained even in a high temperature and high humidity environment, for example. Optical performance and durability are also required for optical films other than polarizing films.
  • Patent Document 1 a polarizing film using PVA having a high degree of polymerization is known (Patent Document 1).
  • film formation is performed using a PVA film formation solution in which PVA having a high degree of polymerization is dissolved in a solvent containing dimethyl sulfoxide as a main component.
  • PVA aqueous solution in which water is used as a solvent as a film-forming solution in consideration of environmental aspects, economic efficiency, and the like.
  • PVA having a high degree of polymerization has poor film-forming property because the viscosity of the aqueous solution increases, which is not preferable for industrial production. Therefore, a method for improving the optical performance and moisture heat resistance of the optical film is desired other than the method for increasing the degree of polymerization of PVA.
  • the present invention has been made based on the above circumstances, and an object thereof is optical performance and moisture heat resistance as compared with the case of using non-modified PVA having good productivity and the same degree of polymerization. It is an object of the present invention to provide a film for producing an optical film capable of obtaining an excellent optical film, a method for producing an optical film using such a film for producing an optical film, and an optical film.
  • a group containing polyvinyl alcohol having a silicon-containing group, and the silicon-containing group can be converted into a silanol group or a silanol group in the presence of water, and the viscosity average degree of polymerization of the polyvinyl alcohol is 1,000 or more.
  • a film for producing an optical film which has a saponification degree of 98.7 mol% or more and a silicon-containing group content of 0.01 mol% or more and 1.0 mol% or less with respect to all structural units; [2] The film for producing an optical film according to [1], which has a saponification degree of 99.5 mol% or more; [3] The film for producing an optical film according to [1] or [2], wherein the product of the viscosity average degree of polymerization and the content of the silicon-containing group is 100 mol% or more and 2,000 mol% or less; [4] A film for producing an optical film according to any one of [1] to [3], which has an average thickness of 1 ⁇ m or more and 75 ⁇ m or less; [5] A film for producing an optical film according to any one of [1] to [4], which has a swelling degree of 140% or more and 400% or less.
  • [6] The film for producing an optical film according to any one of [1] to [5], wherein the optical film is a polarizing film; [7] A film for producing an optical film according to any one of [1] to [6], which is a non-stretched film; [8] A method for producing an optical film, comprising a step of uniaxially stretching the film for producing an optical film according to any one of [1] to [7]; [9] The method for producing an optical film according to [8], wherein the optical film is a polarizing film; [10] A group containing polyvinyl alcohol having a silicon-containing group, and the silicon-containing group can be converted into a silanol group or a silanol group in the presence of water, and the viscosity average degree of polymerization of the polyvinyl alcohol is 1,000 or more.
  • an optical film manufacturing film capable of obtaining an optical film having good productivity and excellent optical performance and moisture heat resistance as compared with the case of using non-modified PVA having the same degree of polymerization, It is possible to provide an optical film manufacturing method and an optical film using such an optical film manufacturing film.
  • the film for producing an optical film of the present invention contains polyvinyl alcohol having a silicon-containing group (hereinafter, may be referred to as "silanol-modified PVA").
  • the silanol-modified PVA is a polymer having a vinyl alcohol unit (-CH 2- CH (OH)-) as a structural unit, and has a silicon-containing group.
  • the silanol-modified PVA may contain a structural unit containing a silicon-containing group, and may further have a vinyl ester unit such as a vinyl acetate unit or another structural unit.
  • the lower limit of the viscosity average degree of polymerization of silanol-modified PVA is 1,000, preferably 2,000, and more preferably 2,500.
  • the film for producing an optical film of the present invention has excellent stretchability, and an optical film having excellent optical performance and moisture heat resistance can be obtained. it can.
  • the upper limit of the viscosity average degree of polymerization is 6,000, preferably 5,000, and more preferably 4,000.
  • the lower limit of the saponification degree of silanol-modified PVA is 98.7 mol%, preferably 99.0 mol%, more preferably 99.5 mol%, further preferably 99.8 mol%, and 99.9 mol%. Especially preferable.
  • the saponification degree is at least the above lower limit, an optical film having excellent optical performance and moisture heat resistance can be obtained.
  • the upper limit of the saponification degree is not particularly limited, but is preferably 99.99 mol% or less from the viewpoint of productivity of silanol-modified PVA.
  • the degree of saponification of PVA is the ratio of the number of moles of vinyl alcohol units to the total number of moles of structural units (typically vinyl ester units) and vinyl alcohol units that can be converted into vinyl alcohol units by saponification (PVA). Mol%).
  • the degree of saponification of PVA can be measured according to the description of JIS K6726-1994.
  • Silanol-modified PVA has a silicon-containing group.
  • This silicon-containing group is a silanol group or a group that can be converted to a silanol group in the presence of water.
  • the silanol group refers to a group having a silicon atom and at least one hydroxy group bonded to the silicon atom.
  • the number of hydroxy groups contained in the silanol group is usually any one of 1 to 3, and is preferably 3.
  • the hydroxy group contained in the silanol group may exist in the state of a salt (for example, -ONa, -OK, etc.).
  • a group that can be converted to a silanol group in the presence of water means a group that can be converted to a silanol group when PVA is hydrolyzed in water under conditions of a reaction time of 2 hours and a reaction temperature of 150 ° C.
  • Examples of the group that can be converted to a silanol group in the presence of water include a group in which at least one alkoxy group or an acyloxy group is bonded to a silicon atom, and specifically, a trimethoxysilyl group and a triethoxysilyl group.
  • Triisopropoxysilyl group dimethoxymethylsilyl group, diethoxymethylsilyl group, methoxydimethylsilyl group, ethoxydimethylsilyl group, triacetoxysilyl group and the like.
  • Examples of the silicon-containing group that is, a silanol group or a group that can be converted to a silanol group in the presence of water, include a group represented by any of the following formulas (1) to (3). Among these, the group represented by the following formula (1) is preferable.
  • R 1 is independently a hydrogen atom, a substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms, or a substituted or unsubstituted acyl group having 1 to 20 carbon atoms. It is a group.
  • R 2 is an independently substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms.
  • Examples of the hydrocarbon group having 1 to 20 carbon atoms represented by R 1 and R 2 include an aliphatic hydrocarbon group, an alicyclic hydrocarbon group (cyclohexyl group, etc.), an aromatic hydrocarbon group (phenyl group, etc.) and the like.
  • the aliphatic hydrocarbon group is preferable.
  • Examples of the aliphatic hydrocarbon group include an alkyl group such as a methyl group, an ethyl group and a propyl group, an alkenyl group such as a vinyl group and an alkynyl group such as an ethynyl group, and an alkyl group is preferable.
  • the number of carbon atoms of the hydrocarbon group represented by R 1 and R 2 is preferably 1 to 6, and more preferably 1 to 3. At least a part of the hydrogen atom contained in the hydrocarbon group represented by R 1 and R 2 may be substituted with a halogen atom, a carboxy group, an alkoxy group (methoxy group, ethoxy group, etc.) and the like.
  • Examples of the acyl group having 1 to 20 carbon atoms represented by R 1 include a group in which a carbonyl group ( ⁇ CO ⁇ ) is bonded to the above-mentioned hydrocarbon group having 1 to 20 carbon atoms. Specific examples thereof include an acetyl group, a propionyl group, and a benzoyl group.
  • the number of carbon atoms of the acyl group represented by R 1 is preferably 1 to 6, and more preferably 1 to 3.
  • At least a part of the hydrogen atom of the acyl group represented by R 1 may be substituted with a halogen atom, a carboxy group, an alkoxy group (methoxy group or the like) or the like.
  • R 1 when at least one of R 1 is a hydrogen atom, this group is a silanol group. Further, in the group represented by any of the above formulas (1) to (3), when all R 1s are not hydrogen atoms, this group is a group that can be converted into a silanol group in the presence of water.
  • R 1 is preferably a hydrogen atom or a substituted or unsubstituted hydrocarbon group having 1 to 20 carbon atoms.
  • the silicon-containing group is directly bonded to the carbon atom in the polymer main chain by the silicon-carbon bond.
  • the content of silicon-containing groups with respect to all structural units of silanol-modified PVA is 0.01 mol% or more and 1.0 mol% or less.
  • silanol-modified PVA having a predetermined amount of silicon-containing groups the optical performance and moist heat resistance of the obtained optical film can be obtained by using non-modified PVA having the same degree of polymerization. Significantly improved compared to film.
  • the non-modified PVA is PVA obtained by saponifying a homopolymer of vinyl ester.
  • the silanol-modified PVA has a lower viscosity of the aqueous solution at a high temperature (for example, 80 ° C.) than the PVA having a high degree of polymerization having the same optical performance of the obtained optical film. Therefore, by using silanol-modified PVA, the optical performance and moist heat resistance of the obtained optical film can be improved while the film for producing the optical film has good productivity (film forming property). Alternatively, by using silanol-modified PVA, the productivity (film-forming property) of the optical film-making film can be improved while the obtained optical film exhibits excellent optical performance and moisture-heat resistance.
  • the lower limit of the content of silicon-containing groups with respect to all structural units of silanol-modified PVA is 0.01 mol%, preferably 0.05 mol%, more preferably 0.1 mol%, further 0.25 mol%. preferable.
  • the upper limit of the content of the silicon-containing group with respect to all the structural units of the silanol-modified PVA is 1.0 mol%, preferably 0.8 mol%, and more preferably 0.6 mol%.
  • the content of the silicon-containing group By setting the content of the silicon-containing group to the above upper limit or less, the water solubility of the silanol-modified PVA and the viscosity stability of the aqueous solution are improved, and the film productivity (film-forming property) can be improved.
  • the content (mol%) of silicon-containing groups can be determined, for example, by proton NMR of the vinyl ester polymer before saponification.
  • the vinyl ester polymer is reprecipitated and purified with hexane-acetone to completely remove unreacted monomers from the polymer, and then at 90 ° C. After drying under reduced pressure for 2 days, it is dissolved in a CDCl 3 solvent and subjected to analysis.
  • the lower limit of the product of the viscosity average degree of polymerization of silanol-modified PVA and the content of silicon-containing groups is preferably 100 mol%, more preferably 300 mol%, further preferably 500 mol%, and particularly preferably 700 mol%.
  • the upper limit of the product is preferably 2,000 mol%, more preferably 1,500, and even more preferably 1,200.
  • the water solubility of the silanol-modified PVA can be further increased, and the productivity of the film for producing the optical film can be further increased.
  • the silanol-modified PVA preferably has a structural unit having a silicon-containing group.
  • Examples of the structural unit having a silicon-containing group include a structural unit represented by the following formula (4).
  • R 3 is a hydrogen atom or a methyl group.
  • R 4 is a single bond or divalent linking group.
  • R 5 is a silicon-containing group.
  • R 3 a hydrogen atom is preferred.
  • R 7 is a group represented by- (CH 2 ) n- above, or a divalent hydrocarbon group containing at least one of an oxygen atom and a nitrogen atom.) The group represented by can be mentioned.
  • Examples of the divalent hydrocarbon group containing at least one oxygen atom and a nitrogen atom -CH 2 CH 2 NHCH 2 CH 2 CH 2 -, - CH 2 CH 2 NHCH 2 CH 2 -, - CH 2 CH 2 NHCH 2 -, -CH 2 CH 2 N (CH 3 ) CH 2 CH 2- , -CH 2 CH 2 N (CH 3 ) CH 2- , -CH 2 CH 2 OCH 2 CH 2 CH 2- , -CH 2 CH 2 OCH 2 CH 2- , -CH 2 CH 2 OCH 2-, etc.
  • the number of carbon atoms of the divalent hydrocarbon group containing at least one of an oxygen atom and a nitrogen atom can be, for example, 2 or more and 6 or less.
  • R 4 is preferably a single bond.
  • silicon-containing group represented by R 5 are as described above, and a group represented by any of the above formulas (1) to (3) can be mentioned, and the above formula (1) can be used.
  • the group represented is preferred.
  • the number of silicon-containing groups contained in the structural unit having silicon-containing groups is not particularly limited, but may be 1.
  • the range of the content of the structural unit having a silicon-containing group with respect to all the structural units of the silanol-modified PVA may be the range of the content of the silicon-containing group with respect to all the structural units described above.
  • the range of the product of the viscosity average degree of polymerization of silanol-modified PVA and the content of the structural unit having a silicon-containing group may be the range of the product of the above-mentioned viscosity average degree of polymerization and the content of the silicon-containing group. ..
  • the silanol-modified PVA may have other structural units other than the vinyl alcohol unit, the vinyl ester unit, and the structural unit having a silicon-containing group.
  • the content of the above other structural units with respect to all the structural units of silanol-modified PVA is preferably 15 mol% or less, more preferably 5 mol% or less, further preferably 1 mol% or less, and 0.1 mol% or less. It may be even more preferable.
  • the silanol-modified PVA is substantially composed of a vinyl alcohol unit, a vinyl ester unit, and a structural unit having a silicon-containing group, the effects of the present invention may be more fully exhibited.
  • the film for producing an optical film may contain one kind of silanol-modified PVA alone, or contains two or more kinds of silanol-modified PVA having different degrees of polymerization, saponification, silicon-containing group content and the like. May be good.
  • the lower limit of the content of silanol-modified PVA in the film for producing an optical film is not particularly limited, but is preferably 50% by mass, more preferably 80% by mass, and even more preferably 85% by mass.
  • the upper limit of this content is not particularly limited, and may be 100% by mass, preferably 99% by mass, and more preferably 95% by mass.
  • the method for producing silanol-modified PVA is not particularly limited. For example, it can be produced by copolymerizing a vinyl ester monomer and a monomer having a silicon-containing group and saponifying the obtained vinyl ester polymer.
  • vinyl ester monomer examples include vinyl formate, vinyl acetate, vinyl propionate, vinyl valerianate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl pivalate, vinyl versatic acid and the like. it can. Among these, vinyl acetate is preferable.
  • Examples of the monomer having a silicon-containing group include vinyltrimethoxysilane, vinylmethyldimethoxysilane, vinyldimethylmethoxysilane, vinyltriethoxysilane, vinylmethyldiethoxysilane, vinyldimethylethoxysilane, allyltrimethoxysilane, and allylmethyldimethoxysilane.
  • the method for copolymerizing the vinyl ester monomer and the monomer having a silicon-containing group is not particularly limited, and examples thereof include known methods such as a massive polymerization method, a solution polymerization method, a suspension polymerization method, and an emulsion polymerization method. Among these methods, a massive polymerization method performed without a solvent and a solution polymerization method performed using a solvent such as alcohol are preferable.
  • the solvent used as a solvent in solution polymerization include esters such as methyl acetate and ethyl acetate; aromatic hydrocarbons such as benzene and toluene; lower alcohols such as methanol and ethanol.
  • azo-based initiators As the initiator used in the copolymerization reaction, conventionally known azo-based initiators, peroxide-based initiators, redox-based initiators and the like are appropriately selected.
  • the azo initiator include 2,2'-azobisisobutyronitrile, 2,2'-azobis (2,4-dimethylvaleronitrile), and 2,2'-azobis (4-methoxy-2,4-). Dimethylvaleronitrile) and the like.
  • Peroxide-based initiators include percarbonate compounds such as dinormalpropyl peroxydicarbonate, diisopropylperoxydicarbonate, di-2-ethylhexyl peroxydicarbonate, and diethoxyethylperoxydicarbonate; t-butylper.
  • Perester compounds such as oxyneodecanate, ⁇ -cumylperoxyneodecanate, t-butylperoxyneodecanate; acetylcyclohexylsulfonyl peroxide, diisobutyryl peroxide; 2,4,4-trimethylpentyl-2- Examples thereof include peroxyphenoxyacetate.
  • potassium persulfate, ammonium persulfate, hydrogen peroxide and the like can be combined with the above-exemplified peroxide-based initiator to prepare the initiator.
  • the redox-based initiator include a combination of the above-mentioned peroxide and a reducing agent such as sodium hydrogen sulfite, sodium hydrogen carbonate, tartaric acid, L-ascorbic acid, and longalit.
  • the polymerization temperature when the copolymerization reaction is carried out is not particularly limited, but is preferably 0 ° C. or higher and 180 ° C. or lower, more preferably 20 ° C. or higher and 160 ° C. or lower, and further preferably 30 ° C. or higher and 150 ° C. or lower.
  • Acrylic acid esters such as i-propyl, n-butyl acrylate, i-butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, octadecyl acrylate; methacrylic acid or a salt thereof; methacryl Methyl acidate, ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, dodecyl methacrylate, methacryl Methacrylate esters such as octadecyl acid; acrylamide, N-methylacrylamide, N-ethylacrylamide, N, N-dimethylacrylamide, diacetoneacrylamide, acrylamide propanesulfonic acid
  • Methacrylate derivatives such as N-vinylformamide, N-vinylacetamide, N-vinylamide such as N-vinylpyrrolidone; methylvinyl ether, ethylvinyl ether, n-propylvinyl ether, i-propylvinyl ether, n-butylvinyl ether, i-butyl Vinyl ethers such as vinyl ether, t-butyl vinyl ether, dodecyl vinyl ether, stearyl vinyl ether; vinyl cyanide such as acrylonitrile and methacrylonitrile; vinyl halide such as vinyl chloride, vinylidene chloride, vinyl fluoride and vinylidene fluoride; allyl acetate, chloride Allyl compounds such as allyl; maleic acid or a salt thereof, ester or acid anhydride; itaconic acid or a salt thereof, ester or acid anhydride; isopropenyl acetate
  • the proportion of structural units derived from the above-mentioned other monomers (monomers other than the vinyl ester monomer and the monomer having a silicon-containing group) in the vinyl ester polymer is not necessarily limited as long as the effect of the present invention is not impaired, but the vinyl ester weight Based on the number of moles of all structural units constituting the coalescence, 15 mol% or less is preferable, 5 mol% or less is more preferable, 1 mol% or less is further preferable, and 0.1 mol% or less may be further preferable. ..
  • the vinyl ester polymer is then saponified in a solvent according to a known method, leading to silanol-modified PVA.
  • Alcohol is preferable as the solvent used for the saponification reaction.
  • the alcohol include lower alcohols such as methanol and ethanol, and methanol is particularly preferably used.
  • the solvent used in the saponification reaction may further contain acetone, an ester such as methyl acetate or ethyl acetate, or an organic solvent such as toluene.
  • the catalyst used in the saponification reaction include hydroxides of alkali metals such as potassium hydroxide and sodium hydroxide, alkaline catalysts such as sodium methylate, and acid catalysts such as mineral acid.
  • the temperature of the saponification reaction can be, for example, 20 ° C. or higher and 60 ° C. or lower.
  • the product is pulverized at that time, washed, and dried to obtain silanol-modified PVA.
  • the film for producing an optical film of the present invention preferably contains a plasticizer. Since the film for producing an optical film contains a plasticizer, the stretchability can be improved.
  • a polyhydric alcohol is preferable as the plasticizer. Examples of the polyhydric alcohol include ethylene glycol, glycerin, propylene glycol, diethylene glycol, diglycerin, triethylene glycol, tetraethylene glycol, trimethylolpropane and the like. Among these, glycerin is preferable from the viewpoint of improving stretchability.
  • the plasticizer one kind or two or more kinds can be used.
  • the lower limit of the content of the plasticizer in the film for producing an optical film of the present invention is preferably 1 part by mass, more preferably 3 parts by mass, and even more preferably 5 parts by mass with respect to 100 parts by mass of silanol-modified PVA.
  • the content of the plasticizer is at least the above lower limit, the stretchability of the film is improved, and the optical performance of the obtained optical film can be further improved.
  • the upper limit of the content of this plasticizer is preferably 20 parts by mass, more preferably 17 parts by mass, and even more preferably 15 parts by mass with respect to 100 parts by mass of silanol-modified PVA.
  • the content of the plasticizer is not more than the above upper limit, it is possible to prevent the film from becoming too flexible and the handleability from being lowered.
  • the film for producing an optical film preferably contains a surfactant.
  • a surfactant By forming a film using a film-forming stock solution containing a surfactant, the film-forming property is improved and the occurrence of thickness unevenness of the film is suppressed, and the film is peeled off from the metal roll or belt used for film-forming. Becomes easier.
  • the resulting film may contain a surfactant.
  • the type of surfactant is not particularly limited, but an anionic surfactant and a nonionic surfactant are preferable from the viewpoint of peelability from a metal roll or a belt.
  • anionic surfactant examples include a carboxylic acid type such as potassium laurate; a sulfate ester type such as polyoxyethylene lauryl ether sulfate and octyl sulfate; and a sulfonic acid type such as dodecylbenzene sulfonate.
  • carboxylic acid type such as potassium laurate
  • a sulfate ester type such as polyoxyethylene lauryl ether sulfate and octyl sulfate
  • a sulfonic acid type such as dodecylbenzene sulfonate.
  • nonionic surfactant examples include an alkyl ether type such as polyoxyethylene oleyl ether; an alkylphenyl ether type such as polyoxyethylene octylphenyl ether; an alkyl ester type such as polyoxyethylene laurate; and a polyoxyethylene lauryl amino ether.
  • Alkylamine type such as; alkylamide type such as polyoxyethylene lauric acid amide; polypropylene glycol ether type such as polyoxyethylene polyoxypropylene ether; alkanolamide type such as laurate diethanolamide and oleic acid diethanolamide; polyoxyalkylene Examples thereof include an allylphenyl ether type such as allylphenyl ether.
  • the surfactant can be used alone or in combination of two or more.
  • the lower limit of the content thereof is preferably 0.01 part by mass, more preferably 0.02 part by mass, and 0.05 part by mass with respect to 100 parts by mass of silanol-modified PVA. Parts by mass are even more preferred.
  • the upper limit of this content is preferably 0.5 parts by mass, more preferably 0.3 parts by mass, and even more preferably 0.1 parts by mass with respect to 100 parts by mass of silanol-modified PVA.
  • the film for producing an optical film of the present invention includes a filler, a processing stabilizer such as a copper compound, a weather resistance stabilizer, a colorant, an ultraviolet absorber, a light stabilizer, an antioxidant, an antistatic agent, and a flame retardant.
  • a processing stabilizer such as a copper compound, a weather resistance stabilizer, a colorant, an ultraviolet absorber, a light stabilizer, an antioxidant, an antistatic agent, and a flame retardant.
  • a processing stabilizer such as a copper compound, a weather resistance stabilizer, a colorant, an ultraviolet absorber, a light stabilizer, an antioxidant, an antistatic agent, and a flame retardant.
  • a processing stabilizer such as a copper compound, a weather resistance stabilizer, a colorant, an ultraviolet absorber, a light stabilizer, an antioxidant, an antistatic agent, and a flame retardant.
  • the film for producing an optical film of the present invention may contain PVA other than the silanol-modified PVA described above.
  • the total proportion of all PVA including silanol-modified PVA, the plasticizer and the surfactant in the film for producing an optical film of the present invention is preferably 80% by mass or more, more preferably 90% by mass or more, and 95% by mass. The above is more preferable, and in some cases, 99% by mass or more is even more preferable.
  • the film for producing an optical film of the present invention is substantially composed of PVA, a plasticizer and a surfactant, the effects of the present invention can be more fully exhibited.
  • the content ratio of the above-mentioned silanol-modified PVA in all PVA contained in the film for producing an optical film of the present invention is preferably 50% by mass or more, more preferably 80% by mass or more, more preferably 90% by mass or more, and more preferably 90% by mass or more. 95% by mass or more is further preferable, and 99% by mass or more is even more preferable.
  • the total proportion of the silanol-modified PVA, the plasticizer and the surfactant in the film for producing an optical film of the present invention is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more. In some cases, 99% by mass or more is even more preferable.
  • the film for producing an optical film of the present invention is substantially composed of silanol-modified PVA, a plasticizer and a surfactant, the effects of the present invention can be more fully exhibited.
  • the film for producing an optical film of the present invention is a so-called raw film used as a material for an optical film.
  • the film for producing an optical film of the present invention is not limited to a roll-shaped film.
  • the average thickness of the film for producing an optical film of the present invention is not particularly limited, but the lower limit is preferably 1 ⁇ m, more preferably 5 ⁇ m, and even more preferably 10 ⁇ m. When the average thickness is at least the above lower limit, it is possible to suppress breakage during the uniaxial stretching process when manufacturing an optical film.
  • the upper limit of the average thickness is preferably 75 ⁇ m, more preferably 60 ⁇ m, further preferably 45 ⁇ m, and even more preferably 35 ⁇ m. When the average thickness is not more than the above upper limit, stretching spots during the uniaxial stretching treatment can be suppressed.
  • the "average thickness” refers to the average value of the thickness measured at any five points (hereinafter, the same applies to the average thickness).
  • the film for producing an optical film of the present invention may be a single-layer film composed of one PVA layer (a layer containing silanol-modified PVA) or a multilayer film including one PVA layer. However, when it is used for producing a polarizing film, it is preferably a single-layer film.
  • the lower limit of the average thickness of the PVA layer contained in the film for producing an optical film of the present invention is preferably 1 ⁇ m, more preferably 5 ⁇ m, still more preferably 10 ⁇ m. When the average thickness is at least the above lower limit, it is possible to suppress breakage during the uniaxial stretching process when manufacturing an optical film.
  • the upper limit of the average thickness is preferably 75 ⁇ m, more preferably 60 ⁇ m, further preferably 45 ⁇ m, and even more preferably 35 ⁇ m.
  • the average thickness is not more than the above upper limit, stretching spots during the uniaxial stretching treatment can be suppressed.
  • the average thickness is preferably 20 ⁇ m or more, more preferably 30 ⁇ m or more, in order to ensure handleability.
  • the average thickness of the PVA layer can be 20 ⁇ m or less, or 15 ⁇ m or less.
  • a multilayer film is a film having two or more layers.
  • the number of layers of the multilayer film may be 5 or less, and may be 3 or less.
  • Examples of the multilayer film include a film for producing an optical film having a laminated structure of a base resin layer and a PVA layer.
  • the average thickness of the base resin layer is, for example, 20 ⁇ m or more and 500 ⁇ m or less.
  • the base resin layer in the multilayer film is preferably one that can be uniaxially stretched together with the PVA layer.
  • polyester, polyolefin or the like can be used as the resin constituting the base resin layer.
  • an amorphous polyester resin is preferable, and polyethylene terephthalate and an amorphous polyester resin obtained by copolymerizing polyethylene terephthalate with a copolymerization component such as isophthalic acid and 1,4-cyclohexanedimethanol are preferably used.
  • An adhesive layer may be provided between the base resin layer and the PVA layer.
  • the width of the film for producing an optical film of the present invention is not particularly limited and can be determined according to its application and the like.
  • the lower limit of the width of the optical film manufacturing film is preferably 3 m.
  • the upper limit of the width of the optical film manufacturing film is preferably 7 m.
  • the degree of swelling of the optical film manufacturing film of the present invention is preferably in the range of 140% or more and 400% or less from the viewpoint of the productivity of the optical film and the optical performance.
  • the lower limit of the degree of swelling is more preferably 180% and even more preferably 190%.
  • the upper limit of the degree of swelling is more preferably 220% and even more preferably 210%.
  • the degree of swelling of the film can be adjusted to a smaller value, for example, by increasing the heat treatment conditions.
  • N represents the mass (g) of the sample after immersing the sample collected from the film in distilled water at 30 ° C. for 30 minutes and then removing the water on the surface.
  • M represents the mass (g) of the sample after drying the sample in a dryer at 105 ° C. for 16 hours.
  • the film for producing an optical film of the present invention is usually a film that is not substantially stretched (non-stretched film, unstretched film).
  • the in-plane phase difference of the raw film for manufacturing an optical film is preferably 100 nm or less, more preferably 50 nm or less.
  • an optical film can be obtained by stretching a film for producing an optical film of the present invention (uniaxial stretching treatment or biaxial stretching treatment).
  • the film for producing an optical film of the present invention it is possible to obtain an optical film having good productivity and excellent optical performance and moisture heat resistance as compared with the case of using non-modified PVA having the same degree of polymerization. ..
  • the optical performance includes light transmission, polarization, and the like.
  • Examples of the optical film that can be produced by the optical film manufacturing film include a polarizing film, a retardation film, a viewing angle improving film, a brightness improving film, and the like, and a polarizing film is preferable.
  • the method for producing the film for producing an optical film of the present invention is not particularly limited, but a method for producing a film having a more uniform thickness and width after film formation can be preferably adopted.
  • it can be produced using silanol-modified PVA and, if necessary, a film-forming stock solution in which one or more of plasticizers, surfactants and other additives are dissolved in a liquid medium. it can.
  • the film-forming stock solution contains at least one of a plasticizer, a surfactant and other additives, it is preferable that these components are uniformly mixed.
  • liquid medium used for preparing the film-forming stock solution examples include water, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, ethylene glycol, glycerin, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, and tri.
  • examples thereof include methylolpropane, ethylenediamine, and diethylenetriamine, and one or more of these can be used. Of these, water is preferable from the viewpoint of environmental load and recoverability.
  • the silanol-modified PVA described above has good water solubility, and an increase in viscosity when used as an aqueous solution at a relatively high temperature (for example, 80 ° C.) is suppressed. From this point as well, water can be preferably used as the liquid medium.
  • the volatile content of the film-forming stock solution (the content of volatile components such as a liquid medium removed by volatilization or evaporation during film-forming in the film-forming stock solution) is preferably, for example, 50% by mass or more and 95% by mass or less, and 55% by mass. % Or more and 90% by mass or less is more preferable, and 60% by mass or more and 85% by mass or less is further preferable.
  • the volatile content of the membrane-forming stock solution is 50% by mass or more, the viscosity of the membrane-forming stock solution does not become too high, filtration and defoaming during preparation of the membrane-forming stock solution are smoothly performed, and a film with few foreign substances and defects. Is easy to manufacture.
  • the volatile fraction of the film-forming stock solution is 95% by mass or less, the concentration of the film-forming stock solution does not become too low, and industrial film production becomes easy.
  • the temperature of the film-forming stock solution at the time of film-forming can be, for example, 70 ° C. or higher and 90 ° C. or lower.
  • Examples of the film forming method when forming a film using the undiluted film forming solution include a cast film forming method, an extrusion film forming method, a wet film forming method, and a gel film forming method. These film forming methods may adopt only one kind or a combination of two or more kinds. Among these film-forming methods, the cast film-forming method and the extrusion film-forming method are preferable because a film having a uniform thickness and width and good physical characteristics can be obtained. The formed film can be dried or heat-treated as needed.
  • Examples of a specific manufacturing method for the optical film manufacturing film of the present invention include the following examples. Using a T-shaped slit die, hopper plate, I-die, lip coater die, etc., the film-forming stock solution is uniformly discharged or uniformly discharged onto the peripheral surface of the rotating heated first roll (or belt) located on the most upstream side. Disseminate. Volatile components are evaporated and dried from one surface of the membrane discharged or cast on the peripheral surface of the first roll (or belt). Subsequently, it is further dried on the peripheral surface of one or more rotating heated rolls arranged on the downstream side thereof, or is further dried by passing through a hot air drying device. Then, the film is wound by the winding device. Drying with a heated roll and drying with a hot air drying device may be carried out in an appropriate combination.
  • a multilayer film can be produced, for example, by applying a film-forming stock solution on a base resin film (base resin layer).
  • base resin layer a base resin film
  • the surface of the base resin film may be modified or an adhesive may be applied to the surface of the base resin film. Good.
  • the method for producing an optical film of the present invention includes a step of uniaxially stretching the above-mentioned film for producing an optical film.
  • a method for producing a polarizing film will be specifically described as an example of a method for producing an optical film.
  • Examples of the method for producing a polarizing film include a dyeing step of dyeing a film for manufacturing an optical film (hereinafter, also referred to as “PVA film”), a stretching step of uniaxially stretching, and a swelling step of further swelling, if necessary.
  • Examples thereof include a method including a cross-linking step for cross-linking, a fixing treatment step for fixing treatment, a washing step for washing, a drying step for drying, and a heat treatment step for heat treatment.
  • the order of each step is not particularly limited, but for example, the swelling step, the dyeing step, the cross-linking step, the stretching step, the fixing treatment step, and the like can be performed in this order. Further, one or more steps can be performed at the same time, and each step can be performed twice or more.
  • the swelling step can be performed by immersing the PVA film in water.
  • the temperature of the water when immersed in water is preferably 20 ° C. or higher and 55 ° C. or lower, more preferably 22 ° C. or higher and 50 ° C. or lower, and further preferably 25 ° C. or higher and 45 ° C. or lower.
  • the time for immersion in water is, for example, preferably 0.1 minutes or more and 5 minutes or less, and more preferably 0.5 minutes or more and 3 minutes or less.
  • the water when immersed in water is not limited to pure water, and may be an aqueous solution in which various components are dissolved, or a mixture of water and an aqueous medium.
  • the dyeing step can be performed by bringing the dichroic dye into contact with the PVA film.
  • Iodine-based pigments are generally used as the dichroic pigments.
  • the timing of dyeing may be any stage before uniaxial stretching, during uniaxial stretching, and after uniaxial stretching.
  • a method of dyeing is preferably performed by immersing the PVA film in a solution (particularly an aqueous solution) containing iodine-potassium iodide, which is a dyeing bath.
  • the concentration of iodine in the dyeing bath is preferably 0.01% by mass or more and 0.5% by mass or less, and the concentration of potassium iodide is preferably 0.01% by mass or more and 10% by mass or less.
  • the temperature of the dyeing bath is preferably 20 ° C. or higher and 50 ° C. or lower, particularly preferably 25 ° C. or higher and 40 ° C. or lower.
  • a suitable dyeing time is 0.2 minutes or more and 5 minutes
  • the cross-linking step is preferably performed after the dyeing step and before the stretching step.
  • the cross-linking step can be performed by immersing the PVA film in an aqueous solution containing a cross-linking agent.
  • a cross-linking agent one or more boron compounds such as borate such as boric acid and borax can be used.
  • the concentration of the cross-linking agent in the aqueous solution containing the cross-linking agent is preferably 1% by mass or more and 15% by mass or less, more preferably 1.5% by mass or more and 7% by mass or less, and further preferably 2% by mass or more and 6% by mass or less. Sufficient stretchability can be maintained when the concentration of the cross-linking agent is within the above range.
  • the aqueous solution containing the cross-linking agent may contain potassium iodide or the like.
  • the temperature of the aqueous solution containing the cross-linking agent is preferably 20 ° C. or higher and 60 ° C. or lower, particularly 25 ° C. or higher and 55 ° C. or lower. By keeping the temperature within the above range, cross-linking can be performed efficiently.
  • the stretching step of uniaxially stretching the PVA film may be performed by either a wet stretching method or a dry stretching method.
  • the wet stretching method it can be carried out in an aqueous solution containing boric acid, in the above-mentioned dyeing bath or in the fixing treatment bath described later.
  • stretching may be carried out at room temperature, stretching may be carried out while heating, or may be carried out in air using a PVA film after water absorption.
  • the wet stretching method is preferable because it can be stretched with high uniformity in the width direction, 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 0.5% by mass or more and 6.0% by mass or less, more preferably 1.0% by mass or more and 5.0% by mass or less, and 1.5% by mass or more and 4. 0% by mass or less is particularly preferable.
  • the boric acid aqueous solution may contain potassium iodide, and the concentration of potassium iodide is preferably 0.01% by mass or more and 10% by mass or less.
  • the stretching temperature in uniaxial stretching is preferably 30 ° C. or higher and 90 ° C. or lower, more preferably 40 ° C. or higher and 80 ° C. or lower, and particularly preferably 50 ° C. or higher and 75 ° C. or lower.
  • the draw ratio in uniaxial stretching is preferably 5 times or more, and more preferably 5.5 times or more from the viewpoint of the polarization performance of the obtained polarizing film.
  • the upper limit of the draw ratio is not particularly limited, but the draw ratio is preferably 8 times or less.
  • uniaxial stretching in the long direction can be adopted. Since a polarizing film having excellent polarization performance can be obtained, uniaxial stretching in the long direction is preferable.
  • Uniaxial stretching in the long direction can be performed by using a stretching device including a plurality of rolls parallel to each other and changing the peripheral speed between the rolls.
  • the lateral uniaxial stretching can be performed using a tenter type stretching machine.
  • a fixing treatment step can be performed after the stretching step in order to strengthen the adsorption of the dichroic dye (iodine dye, etc.) on the PVA film.
  • the fixing treatment bath used for the fixing treatment an aqueous solution containing one or more kinds of boron compounds such as boric acid and borax can be used. Further, if necessary, an iodine compound or a metal compound may be added to the fixing treatment bath.
  • the concentration of the boron compound in the fixing treatment bath is preferably 2% by mass or more and 15% by mass or less, particularly preferably 3% by mass or more and 10% by mass or less.
  • the temperature of the fixing treatment bath is preferably 15 ° C. or higher and 60 ° C. or lower, particularly preferably 25 ° C. or higher and 40 ° C. or lower.
  • the cleaning process is generally performed by immersing the film in distilled water, pure water, an aqueous solution, or the like.
  • an aqueous solution containing iodide such as potassium iodide
  • concentration of iodide is preferably 0.5% by mass or more and 10% by mass or less.
  • the temperature of the aqueous solution in the cleaning treatment is generally 5 ° C. or higher and 50 ° C. or lower, preferably 10 ° C. or higher and 45 ° C. or lower, and further preferably 15 ° C. or higher and 40 ° C. or lower.
  • the conditions of the drying step are not particularly limited, but it is preferable to dry the PVA film at a temperature of 30 ° C. or higher and 150 ° C. or lower, particularly 50 ° C. or higher and 130 ° C. or lower. By drying at a temperature within the above range, a polarizing film having excellent dimensional stability can be easily obtained.
  • An optical film other than the polarizing film, such as a retardation film, can also be produced by a method including a step of uniaxially stretching the film for producing an optical film of the present invention.
  • a specific manufacturing method a conventionally known method can be adopted except that the film for manufacturing an optical film of the present invention is used.
  • the optical film of the present invention contains PVA (silanol-modified PVA) having a silicon-containing group, and the silicon-containing group is a group that can be converted into a silanol group in the presence of silanol group or water, and the silanol-modified PVA
  • the viscosity average degree of polymerization is 1,000 or more and 6,000 or less
  • the degree of saponification is 98.7 mol% or more
  • the content of the silicon-containing group with respect to all structural units is 0.01 mol% or more and 1.0 mol% or less.
  • the optical film of the present invention may be an optical film obtained by the above-mentioned manufacturing method using the film for manufacturing the optical film of the present invention.
  • the specific structure, content, and the like of the silanol-modified PVA contained in the optical film of the present invention are the same as those of the silanol-modified PVA contained in the film for producing an optical film of the present invention.
  • the optical film of the present invention may contain other components similar to the film for producing an optical film of the present invention.
  • the optical film of the present invention may be a polarizing film, a retardation film, a viewing angle improving film, a brightness improving film, or the like, and is preferably a polarizing film.
  • the polarizing film usually contains a dichroic dye, and the silanol-modified PVA may be crosslinked.
  • the optical film of the present invention is preferably a stretched film, more preferably a uniaxially stretched film. Further, the optical film of the present invention may be a single-layer film or a multilayer film, but a single-layer film is preferable. In the case of such a film, the optical film of the present invention can be more preferably used as a polarizing film or the like.
  • the dichroism ratio (R) of the polarizing film is preferably 100 or more.
  • a polarizing film having such a high dichroism ratio (R) can be produced with high productivity.
  • the dichroism ratio (R) is more preferably 150 or more, and even more preferably 190 or more.
  • the upper limit of the dichroism ratio (R) is, for example, 350 and may be 300.
  • the polarizing film 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 thereof.
  • a protective film a cellulose triacetate (TAC) film, a cycloolefin polymer (COP) film, a cellulose acetate / butyrate (CAB) film, an acrylic film, a polyester film, or the like is used.
  • the adhesive for bonding include a PVA-based adhesive, a urethane-based adhesive, and an acrylate-based ultraviolet curable adhesive. That is, the polarizing plate has a polarizing film and a protective film laminated directly or via an adhesive layer on one side or both sides of the polarizing film.
  • the polarizing plate can be used as an LCD component by, for example, coating it with an adhesive such as acrylic and then adhering it to a glass substrate.
  • a retardation film, a viewing angle improving film, a brightness improving film, or the like may be further attached to the polarizing plate.
  • the dichroism ratio (R) of the polarizing film was calculated by solving the following equations (a) and (b) from the obtained simple substance transmittance (T) and polarization degree (V) values.
  • T transmittance
  • V polarization degree
  • T' T / (1-0.04) 2
  • R ⁇ -ln [T'(1-V)] ⁇ / ⁇ -ln [T'(1 + V)] ⁇ ... (b)
  • the polymerization reaction was carried out for 3 hours while adding 135 g of methanol containing 2.5% by mass of vinylmethoxysilane into the system, and the polymerization was stopped at that time.
  • the polymerization rate at the time when the polymerization reaction was stopped was 26.8%.
  • the polymerization temperature was maintained at 60 ° C. during the polymerization.
  • unreacted vinyl acetate was removed under reduced pressure to obtain a methanol solution of polyvinyl acetate (hereinafter, may be abbreviated as PVAc).
  • the concentration of the obtained PVAC methanol solution was adjusted to 23.5%, and the NaOH methanol solution (10) so that the alkali molar ratio (the number of moles of NaOH / the number of moles of vinyl ester units in PVAc) was 0.04. % Concentration) was added and the mixture was saponified.
  • the obtained polyvinyl alcohol was washed with methanol.
  • the degree of polymerization (viscosity average degree of polymerization) of PVA-1 obtained by the above operation was 2,400, the degree of saponification was 99.9 mol%, the content of silicon-containing groups was 0.2 mol%, and the temperature was 80 ° C.
  • the viscosity of the 10 mass% aqueous solution was 920 mPa ⁇ s.
  • Example 1 An aqueous solution containing 100 parts by mass of PVA-1, 10 parts by mass of glycerin as a plasticizer, and 0.1 parts by mass of polyoxyethylene lauryl ether sodium sulfate as a surfactant, and having a PVA content of 9.5% by mass is formed into a film. Prepared as undiluted solution. This film-forming stock solution is dried on a metal roll at 80 ° C., and the obtained film is heat-treated at a temperature of 120 ° C. for 10 minutes in a hot air dryer to adjust the degree of swelling to 200% and have an average thickness. A PVA film (film for producing an optical film) having a thickness of 30 ⁇ m was produced.
  • a sample having a width of 5 cm and a length of 9 cm was cut from the central portion of the obtained PVA film in the width direction so that a range of 5 cm in width ⁇ 5 cm in length could be uniaxially stretched.
  • This sample was uniaxially stretched 2.0 times in the length direction while being immersed in pure water at 30 ° C. for 60 seconds for swelling treatment. Subsequently, it was immersed in an aqueous solution containing 0.05% by mass of iodine and 5.0% by mass of potassium iodide (dyeing treatment bath: temperature 32 ° C.) for 120 seconds while being 1.2 times longer (2.4 times as a whole). Iodine was adsorbed by uniaxial stretching in the longitudinal direction.
  • the boric acid was uniaxially stretched 1.25 times (3.0 times in total) while being immersed in an aqueous solution containing 2.6% by mass of boric acid (boric acid cross-linking treatment bath: temperature 32 ° C.) for 120 seconds. .. Further, while immersing in an aqueous solution (uniaxial stretching treatment bath) at 58 ° C. containing 2.8% by mass of boric acid and 5% by mass of potassium iodide, the whole is uniaxially stretched up to 6.0 times in the length direction. did. Then, the film was washed by immersing it in a potassium iodide aqueous solution (washing bath) having a temperature of 22 ° C. containing 1.5% by mass of boric acid and 3.5% by mass of potassium iodide for 5 seconds. Finally, it was dried at 80 ° C. for 4 minutes to obtain a polarizing film.
  • boric acid boric acid cross-linking treatment bath: temperature 32 ° C.
  • Examples 2 to 5 and Comparative Examples 1 to 4 Using the PVAs (PVA-2 to PVA-9) listed in Tables 1 to 3, the PVA content and heat treatment temperature of the film-forming stock solution so that the average thickness of the PVA film is 30 ⁇ m and the swelling degree is 200%.
  • the PVA film was prepared and evaluated in the same manner as in Example 1 except that the above was adjusted.
  • a polarizing film was produced and evaluated in the same manner as in Example 1. The results are shown in Tables 1 to 3.
  • PVA-10 was used as PVA, and PVA was adjusted in the same manner as in Example 1 except that the PVA content of the film-forming stock solution and the heat treatment temperature were adjusted so that the average thickness of the PVA film was 30 ⁇ m and the swelling degree was 200%. A film was prepared. However, it broke in the uniaxial stretching treatment bath, and a polarizing film could not be obtained.
  • the PVA1 to PVA-5 used in Examples 1 to 5 have sufficient water solubility, so that a film-forming stock solution can be prepared, and the obtained PVA film can be prepared. (Film for manufacturing an optical film) could be sufficiently stretched to obtain a polarizing film. As described above, it can be seen that the PVA films of Examples 1 to 5 have good productivity. Further, the polarizing films obtained from the PVA films of Examples 1 to 5 are superior in optical performance (dichroism ratio) and moisture heat resistance as compared with the polarizing films using non-modified PVA having the same degree of polymerization. It was.
  • the polarizing films of Examples 1 to 3 using silanol-modified PVA having a degree of polymerization of 2,400 were compared using non-modified PVA having a degree of polymerization of 2,400.
  • the dichroism ratio was high and the amount of decrease in degree of polymerization was small.
  • the polarizing film of Example 4 using a silanol-modified PVA having a degree of polymerization of 3,300 has a higher dichroism ratio than the polarizing film of Comparative Example 2 using a non-modified PVA having a degree of polymerization of 3,300.
  • the amount of increase in transparency and the amount of decrease in degree of polarization were small.
  • the polarizing film of Example 5 using the silanol-modified PVA having a degree of polymerization of 1,700 has two colors as compared with the polarizing films of Comparative Example 3 and Comparative Example 4 using the non-modified PVA having a degree of polymerization of 1,700.
  • the sex ratio was high, and the amount of increase in transparency and the amount of decrease in degree of polarization were small.
  • Comparative Example 2 uses PVA having a higher degree of polymerization than Comparative Example 1.
  • Example 1 uses PVA modified with silanol with respect to Comparative Example 1.
  • the dichroism ratio of Comparative Example 2 is 201, and the dichroism ratio of Example 1 is 208, both of which have the same dichroism ratio as that of Comparative Example 1 having a dichroism ratio of 162. It is increasing.
  • the viscosity of PVA in Comparative Example 1 was 910 mPa ⁇ s, whereas the viscosity of PVA in Comparative Example 2 was 2,740 mPa ⁇ s, which was significantly increased.
  • the viscosity of PVA of Example 1 is 920 mPa ⁇ s, and the increase in viscosity is suppressed. That is, according to the silanol-modified PVA of the example, it can be said that the optical performance and the heat resistance to moisture and heat of the optical film can be improved while maintaining good film forming property (productivity).
  • the film for producing an optical film of the present invention can be suitably used as a material such as a polarizing film which is a constituent material of an LCD.

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Abstract

La présente invention concerne : un film pour la production d'un film optique, ledit film ayant une bonne productivité, tout en permettant l'obtention d'un film optique qui présente une excellente performance optique et une excellente résistance à la chaleur humide par comparaison avec les cas où un PVA non modifié ayant le même degré de polymérisation est utilisé ; un procédé de production d'un film optique, ledit procédé utilisant ce film pour la production d'un film optique ; et un film optique. La présente invention concerne un film pour la production d'un film optique, ledit film contenant un alcool polyvinylique ayant un groupe contenant du silicium, le groupe contenant du silicium étant un groupe silanol ou un groupe qui peut être converti en un groupe silanol en présence d'eau ; l'alcool polyvinylique ayant un degré de polymérisation moyen en viscosité de 1000 à 6000 et un degré de saponification de 98,7 % en mole ou plus ; et la teneur du groupe contenant du silicium par rapport à toutes les unités structurales est de 0,01 % en mole à 1,0 % en mole.
PCT/JP2020/036028 2019-10-08 2020-09-24 Film pour la production d'un film optique, procédé de production d'un film optique, et film optique WO2021070622A1 (fr)

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KR1020227007705A KR20220074860A (ko) 2019-10-08 2020-09-24 광학 필름 제조용 필름, 광학 필름의 제조 방법, 및 광학 필름
CN202080070727.0A CN114450329A (zh) 2019-10-08 2020-09-24 光学膜制造用膜、光学膜的制造方法和光学膜
JP2021551156A JPWO2021070622A1 (fr) 2019-10-08 2020-09-24

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WO2022097336A1 (fr) * 2020-11-09 2022-05-12 株式会社クラレ Film de production de film optique, procédé de production d'un film optique, et film optique
WO2022102185A1 (fr) * 2020-11-11 2022-05-19 株式会社クラレ Film de fabrication de film optique, et procédé de fabrication de film optique

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US4818624A (en) * 1986-12-19 1989-04-04 Polaroid Corporation, Patent Department Stabilized light-polarizing material
JP2011053234A (ja) * 2008-01-11 2011-03-17 Nippon Kayaku Co Ltd 染料系偏光素子及び偏光板、並びにその製造方法
WO2014112625A1 (fr) * 2013-01-21 2014-07-24 日本合成化学工業株式会社 Résine à base de polyalcool de vinyle contenant un groupe silyle et utilisation associée
US20160152876A1 (en) * 2014-11-28 2016-06-02 Samsung Sdi Co., Ltd. Adhesive composition for polarizing plate, adhesive film for polarizing plate prepared using the same, polarizing plate comprising the same and optical display comprising the same
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WO2022097336A1 (fr) * 2020-11-09 2022-05-12 株式会社クラレ Film de production de film optique, procédé de production d'un film optique, et film optique
WO2022102185A1 (fr) * 2020-11-11 2022-05-19 株式会社クラレ Film de fabrication de film optique, et procédé de fabrication de film optique

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