WO2018235610A1 - 原反フィルム、延伸光学フィルムの製造方法、及び延伸光学フィルム - Google Patents
原反フィルム、延伸光学フィルムの製造方法、及び延伸光学フィルム Download PDFInfo
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- WO2018235610A1 WO2018235610A1 PCT/JP2018/021829 JP2018021829W WO2018235610A1 WO 2018235610 A1 WO2018235610 A1 WO 2018235610A1 JP 2018021829 W JP2018021829 W JP 2018021829W WO 2018235610 A1 WO2018235610 A1 WO 2018235610A1
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- film
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- resin particles
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- stretched optical
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Classifications
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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
- B29C55/00—Shaping by stretching, e.g. drawing through a die; Apparatus therefor
- B29C55/02—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
- B29C55/04—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets uniaxial, e.g. oblique
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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
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/30—Polarising elements
Definitions
- the present invention relates to a raw film, a method for producing a stretched optical film, and a stretched optical film.
- a polarizing plate having a light transmission and shielding function 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 laminated on the surface of the polarizing film in order to prevent the color fading of the polarizing film or to prevent the shrinkage of the polarizing film.
- TAC cellulose triacetate
- an iodine type pigment (Hereinafter, a "vinyl alcohol type polymer” may be called “PVA.")
- PVA a vinyl alcohol type polymer film
- Those in which I 3 - and I 5 - etc. are adsorbed are in the mainstream.
- LCDs are used in a wide range of applications such as small devices such as calculators and watches, smartphones, notebook computers, liquid crystal monitors, liquid crystal color projectors, liquid crystal televisions, navigation systems for vehicles, and measuring instruments used indoors and out.
- applications such as smartphones, notebook computers, liquid crystal televisions, navigation systems for vehicles, etc.
- polarizing films having high polarization performance are required.
- smartphones when the transmittance is 42%, the degree of polarization is 99.99% or more High polarization performance is needed.
- thinning and weight reduction are required, and thinning of a polarizing film is also demanded.
- thin polarizing films have low tear strength and are easy to tear.
- Patent Document 1 As methods for producing a polarizing film having high polarizing performance and methods for producing a polarizing film for preventing tearing, methods described in Patent Document 1 and Patent Document 2 below are known.
- patent document 1 the polarizing film with high polarization performance is obtained by using a water-soluble antioxidant to remove iodine adsorbed excessively to the PVA film.
- a water-soluble antioxidant to remove iodine adsorbed excessively to the PVA film.
- Patent Document 2 a thin polarizing film is manufactured by extending
- the method of Patent Document 2 is insufficient in the effect of increasing the tear strength of the polarizing film.
- the tearing strength can be increased by lowering the stretching ratio of the polarizing film, it is not preferable because the polarizing performance is lowered.
- the present invention has been made based on the above circumstances, and an object thereof is a thin film, a raw film capable of obtaining a stretched optical film having a large tear strength and an excellent optical property, and a thin film, Abstract: A stretched optical film having high tear strength and excellent optical properties, and a method for producing such a stretched optical film.
- An average thickness is 45 ⁇ m or less and contains a vinyl alcohol polymer as a main component, and resin particles having an average particle diameter of 25 nm to 150 nm, and the content of the resin particles is 1% by mass to 25
- stretching optical film provided with the process of extending
- An average thickness is 20 ⁇ m or less and contains a vinyl alcohol polymer as a main component and resin particles having an average particle diameter of 25 nm to 150 nm, and the content of the resin particles is 1% by mass to 25 A stretched optical film having a mass% or less.
- a raw film capable of obtaining a stretched optical film having a thin thickness, high tear strength and excellent optical characteristics, and a thin stretched film having a large tear strength and excellent optical characteristics, and It is possible to provide a method of producing a stretched optical film.
- the raw film film which concerns on one Embodiment of this invention is a film used for manufacture of a stretched optical film. That is, the said raw film is a film used as the material of extending
- a stretched optical film is obtained by stretching the raw film.
- the raw film may be a single layer film or a multilayer film (laminate).
- the film etc. which have the PVA layer formed by the coating method etc. on the thermoplastic resin film can be mentioned, for example. It is preferable that it is a single layer film from the point of the point in which the effect of this invention is exhibited much more remarkably, the complexity of lamination
- the upper limit of the average thickness of the raw film is 45 ⁇ m, preferably 40 ⁇ m, more preferably 35 ⁇ m, and still more preferably 30 ⁇ m.
- a thin stretched optical film can be obtained because the average thickness of the raw film is equal to or less than the above upper limit.
- the lower limit of the average thickness is preferably 5 ⁇ m, more preferably 10 ⁇ m, still more preferably 15 ⁇ m, and still more preferably 20 ⁇ m.
- the tear strength of the stretched optical film obtained can be further increased by the average thickness of the raw film being equal to or more than the above lower limit.
- PVA polyvinyl alcohol polymer
- a main component means the component with the largest content on a mass basis (following, the same).
- PVA is a polymer having a vinyl alcohol unit (—CH 2 —CH (OH) —) as a structural unit.
- PVA may have vinyl ester units and other units in addition to vinyl alcohol units.
- the method for producing PVA is not particularly limited. For example, by the step of (1) obtaining a vinyl ester polymer, and (2) saponifying the obtained vinyl ester polymer, ie, converting the vinyl ester unit of the vinyl ester polymer into a vinyl alcohol unit, PVA can be produced.
- the vinyl ester polymer may be a homopolymer consisting only of a vinyl ester monomer, and it is a copolymer of a vinyl ester monomer and another monomer copolymerizable therewith. It may be.
- the vinyl ester monomer is not particularly limited, and examples thereof include vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl versatate, vinyl caproate, vinyl caprylate and vinyl caprate. And vinyl laurate, vinyl palmitate, vinyl stearate, vinyl oleate, vinyl benzoate and the like. Among these, vinyl acetate is preferred from the economical point of view.
- Examples of the monomer copolymerizable with the vinyl ester monomer include ⁇ -olefins having 2 to 30 carbon atoms such as ethylene, propylene, 1-butene and isobutene; (Meth) acrylic acid or a salt thereof; Methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i-propyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, (Meth) acrylic acid esters such as t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, dodecyl (meth) acrylate, octadecyl (meth) acrylate; (Meth) acrylamide; N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N,
- the vinyl ester copolymer may have a structural unit derived from one or more of the other monomers.
- the above-mentioned other monomers may be previously present in the polymerization system when the vinyl ester monomer is subjected to the polymerization reaction, or may be added to the system during the progress of the polymerization reaction, etc. It can be used.
- ⁇ -olefins are preferable, and ethylene is more preferable.
- the stretchability is improved and the film can be stretched at a higher temperature, the occurrence of troubles such as stretch breakage at the time of stretched optical film production is reduced, and the productivity of the stretched optical film is further improved.
- the lower limit of the content of the ⁇ -olefin unit is preferably 1 mol%, more preferably 2 mol%, based on all structural units.
- 4 mol% is preferable and 3 mol% of the upper limit of this content rate is more preferable.
- the polymerization system for polymerizing the vinyl ester monomer may be any system such as batch polymerization, semi-batch polymerization, continuous polymerization, and semi-continuous polymerization.
- a polymerization method known methods such as bulk polymerization method, solution polymerization method, suspension polymerization method, emulsion polymerization method and the like can be applied.
- a bulk polymerization method in which the polymerization is allowed to proceed without solvent, or a solution polymerization method in which the polymerization is allowed to proceed in a solvent such as alcohol is employed.
- an emulsion polymerization method is also preferable.
- the solvent for the solution polymerization method is not particularly limited, and is, for example, an alcohol.
- the alcohol used as the solvent for the solution polymerization method include lower alcohols such as methanol, ethanol and propanol.
- the amount of the solvent used in the polymerization system may be selected in consideration of the chain transfer of the solvent according to the degree of polymerization of the target PVA, for example, when the solvent is methanol, all monomers contained in the solvent and the polymerization system
- the polymerization initiator to be used for the polymerization of the vinyl ester monomer is selected according to the polymerization method from known polymerization initiators such as azo initiators, peroxide initiators, redox initiators, etc. Good.
- azo initiator for example, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (4-methoxy-2,4 -Dimethyl valeronitrile) etc. can be mentioned.
- peroxide initiators include percarbonate compounds such as diisopropyl peroxy dicarbonate, di-2-ethylhexyl peroxy dicarbonate and diethoxyethyl peroxy dicarbonate; t-butyl peroxy neodecanate, ⁇ -Perester compounds such as cumylperoxy neodecanate; acetylcyclohexylsulfonyl peroxide; 2,4,4-trimethylpentyl-2-peroxyphenoxyacetate; acetyl peroxide and the like. Potassium persulfate, ammonium persulfate, hydrogen peroxide or the like may be combined with the above initiator to form a polymerization initiator.
- the redox initiator examples include a polymerization initiator in which the above-mentioned peroxide initiator is combined with a reducing agent such as sodium bisulfite, sodium bicarbonate, sodium tartrate, tartaric acid, L-ascorbic acid, Rongalite and the like.
- the amount of the polymerization initiator to be used is not generally determined because it varies depending on the type of polymerization initiator, but may be selected according to the polymerization rate. For example, in the case of using 2,2′-azobisisobutyronitrile or acetyl peroxide as a polymerization initiator, 0.01 to 0.2 mol% is preferable, 0.02 to 0 based on the vinyl ester monomer. .15 mol% is more preferred.
- the polymerization temperature is not particularly limited, but is suitably about room temperature to 150 ° C., preferably 40 ° C. or more and not more than the boiling point of the solvent used.
- the polymerization of the vinyl ester monomer may be carried out in the presence of a chain transfer agent.
- chain transfer agents include aldehydes such as acetaldehyde and propionaldehyde; ketones such as acetone and methyl ethyl ketone; mercaptans such as 2-hydroxyethanethiol; phosphinates such as sodium phosphinate monohydrate; Can.
- aldehydes and ketones are preferably used.
- the amount of the chain transfer agent used can be determined according to the chain transfer coefficient of the chain transfer agent used and the degree of polymerization of the target PVA, but generally it is 0. 0. to 100 parts by weight of the vinyl ester monomer. 1 to 10 parts by mass is preferred.
- the saponification of the vinyl ester polymer can be performed, for example, in a state in which the vinyl ester polymer is dissolved in an alcohol as a solvent or a water-containing alcohol.
- the alcohol used for saponification include lower alcohols such as methanol and ethanol, with preference given to methanol.
- the solvent used for saponification may contain other solvents such as acetone, methyl acetate, ethyl acetate, benzene and the like in a proportion of, for example, 40% by mass or less of the mass.
- the catalyst used for saponification is, for example, hydroxides of alkali metals such as potassium hydroxide and sodium hydroxide, alkali catalysts such as sodium methylate, and acid catalysts such as mineral acid.
- the temperature for saponification is not limited, but is preferably in the range of 20 to 60.degree.
- the product can be pulverized, washed and dried to obtain PVA.
- the saponification method can apply a well-known method not only the method mentioned above.
- the lower limit of the polymerization degree of PVA is preferably 1,500, more preferably 1,800, and still more preferably 2,000.
- the upper limit is preferably 6,000, more preferably 5,000, and still more preferably 4,000.
- the degree of polymerization of PVA means an average degree of polymerization measured according to the description of JIS K 6726-1994.
- the lower limit of the degree of saponification of PVA is preferably 95 mol%, more preferably 96 mol%, and still more preferably 98 mol% from the viewpoint of water resistance of the stretched optical film obtained from the raw film and the like.
- the upper limit of the degree of saponification may be substantially 100 mol%.
- 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) that can be converted to vinyl alcohol units by saponification and vinyl alcohol units (mol% Say). The degree of saponification can be measured according to the description of JIS K6726-1994.
- the raw film contains resin particles.
- the raw film can increase the tear strength of the obtained stretched optical film by containing a predetermined size and a predetermined amount of resin particles. The reason why such effects occur is not clear, but when the cross section of the stretched optical film produced from the raw film was observed when the cross section was observed, it was dispersed in the film because the cross section became rough. It is presumed that the fine resin particles suppress the propagation of the tear, thereby increasing the tear strength.
- the resin particles are particles whose main component is a polymer (resin).
- the lower limit of the content of the polymer in the resin particles is, for example, 50% by mass, preferably 80% by mass, and more preferably 95% by mass.
- the resin particles may be formed substantially only of resin.
- the lower limit of the average particle diameter of the resin particles is 25 nm, preferably 30 nm, and more preferably 50 nm.
- the average particle diameter of the resin particles is not less than the above lower limit, aggregation of the resin particles can be suppressed, and the resin particles can be favorably dispersed in the raw film. Thereby, the tearing strength of the stretched optical film obtained is increased.
- the upper limit of the average particle diameter is 150 nm, preferably 100 nm, more preferably 80 nm, and even more preferably 60 nm.
- the average particle size of the resin particles exceeds the above upper limit, the specific surface area of the resin particles decreases, so the interaction with PVA decreases, and the improvement of the tear strength of the stretched optical film obtained from the raw film is not good. It will be enough. In addition, since the raw film tends to be clouded, it is unsuitable as an optical film material.
- the average particle diameter of the resin particle in the said raw film says the value measured by the following method.
- the raw film is stirred with hot water at 95 ° C. for 4 hours to dissolve PVA.
- the solution is cooled to 25 ° C., and if necessary, the solution is filtered with, for example, a membrane filter with a pore diameter of 5 ⁇ m to remove insolubles other than resin particles, to obtain a dispersion of resin particles.
- This dispersion is measured by a dynamic light scattering method, and this measured value is taken as the average particle size of the resin particles.
- the method for removing insolubles other than resin particles is not particularly limited, and methods other than filtration may be used.
- the removal process such as the above-mentioned filtration can be omitted. The same applies to the stretched optical film described later.
- the lower limit of the content of resin particles in the raw film is 1% by mass, preferably 3% by mass, and more preferably 6% by mass. By making content of a resin particle more than the said minimum, the tearing strength of the stretched optical film obtained can be enlarged.
- the upper limit of the content is 25% by mass, preferably 20% by mass, and more preferably 15% by mass.
- the raw film may become cloudy.
- the optical properties (polarization performance and the like) of the stretched optical film obtained from the raw film are deteriorated. Although the reason for this is not clear, it is presumed that the resin particles inhibit the orientation of PVA.
- content of the resin particle in the said raw film says the value measured by the following method.
- the raw film is stirred with hot water at 95 ° C. for 4 hours to dissolve it. Thereafter, the solution is cooled to 25 ° C., and if necessary, the solution is filtered with, for example, a membrane filter with a pore diameter of 5 ⁇ m to remove insolubles other than resin particles, to obtain a dispersion of resin particles.
- This dispersion is filtered three times with a membrane filter with a pore size of 0.025 ⁇ m.
- the total mass of resin particles captured in three filtrations is taken as the mass of resin particles in the raw film.
- the mass of the resin particles determined above with respect to the mass of the raw film is taken as the content (% by mass) of the resin particles in the raw film.
- the method for removing insolubles other than resin particles is not particularly limited, and methods other than filtration may be used. Moreover, when the raw film does not contain an insoluble matter other than the resin particles, the removal process such as the above-mentioned filtration can be omitted. The same applies to the stretched optical film described later.
- the resin particles contain a polymer.
- the polymer is not particularly limited, and may be polyolefin, polycarbonate, polyurethane, acrylic resin or the like, but a polymer having a structural unit having a group containing a hydroxy group (—OH) is preferable.
- —OH a polymer having a structural unit having a group containing a hydroxy group
- the tear strength of the obtained stretched optical film can be further increased.
- a polymer having a structural unit having a group containing a hydroxy group has high affinity with PVA, and therefore, resin particles containing such a polymer have dispersibility in a film. It is speculated to be particularly high.
- the group containing a hydroxy group includes not only a hydroxy group but also a group composed of a hydroxy group and another group.
- Examples of the group composed of a hydroxy group and another group include a carboxy group (—COOH), a sulfo group (—SO 2 OH) and the like.
- a part or all of the hydroxy group may be in the form of a salt (anion). That is, the group containing a hydroxy group also includes, for example, a group in the form of a salt represented by -OX, -COOX, -SO 2 OX (X represents an alkali metal atom) or the like.
- a polymer provided with a structural unit having a group containing a hydroxy group can be obtained by polymerizing a monomer having a group containing a hydroxy group by a known method.
- the polymer may be a copolymer having a structural unit other than a structural unit having a group containing a hydroxy group.
- a polymer comprising a structural unit having a hydroxy group can also be obtained by saponifying a polymer comprising a vinyl ester unit. Moreover, the polymer provided with the structural unit which has a carboxy group can be obtained also by carrying out the modification process of the polymer provided with (meth) acrylic acid ester units, such as a (meth) acrylic acid methyl unit.
- structural units having a group containing a hydroxy group structural units having a carboxy group are preferable, and (meth) acrylic acid units (-CH 2 -CH (COOH)-and -CH 2 -C (CH 3 ) (COOH) -) Is more preferred.
- the lower limit of the content of the structural unit having a hydroxyl group-containing group in the total structural units of the polymer may be, for example, 5% by mass or 20% by mass.
- the upper limit of the content may be 100% by mass, but may be 60% by mass or 40% by mass.
- the said polymer when it is a copolymer, it can have a (meth) acrylic-acid alkylester unit etc. as another structural unit, for example.
- the polymer is preferably a block copolymer.
- a block copolymer By being a block copolymer, the effect of the present invention can be further enhanced by improving the dispersibility, elasticity, and the like of the resin particles.
- the copolymer of the block provided with the structural unit which has a group containing a hydroxyl group, and the block provided with the structural unit derived from (meth) acrylic-acid alkylester can be mentioned.
- (meth) acrylic acid alkyl ester methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, etc., having 1 carbon atom
- (Meth) acrylic acid alkyl ester having an alkyl group of ⁇ 6 is preferable, and butyl (meth) acrylate is more preferable.
- Particularly preferable block copolymers include block copolymers of (meth) acrylic acid-butyl (meth) acrylate and the like, and (meth) acrylic acid units and (meth) acrylic acid alkyl ester units.
- the block copolymer can be synthesized by a known method.
- the block copolymer may be a diblock copolymer, a triblock copolymer, or the like.
- the polymer is preferably an elastomer, more preferably a thermoplastic elastomer.
- the tearing strength of the stretched optical film can be further increased by using an elastomeric resin particle.
- the copolymer of the (meth) acrylic acid unit and the (meth) acrylic acid alkyl ester unit can be exemplified as a suitable thermoplastic elastomer.
- an elastomer means resin which has elasticity at normal temperature (for example, 20 degreeC).
- the resin particles may be particles formed of one type of polymer, or particles having a so-called core-shell type structure with different inner and outer materials may be used.
- the material on the shell side is preferably a polymer having a structural unit having a group containing a hydroxy group.
- the resin particles can be produced by a known method. Moreover, a resin particle may use a commercial item. Moreover, the method of making the said raw film film contain a resin particle is not specifically limited, either. For example, resin particles may be added to a PVA chip, or resin particles may be added to a film forming solution used for film formation.
- the raw film can further contain a plasticizer.
- a plasticizer include polyhydric alcohols, and specific examples include ethylene glycol, glycerin, propylene glycol, diethylene glycol, diglycerin, triethylene glycol, tetraethylene glycol, trimethylolpropane and the like.
- ethylene glycol, glycerin, propylene glycol, diethylene glycol, diglycerin, triethylene glycol, tetraethylene glycol, trimethylolpropane and the like One or more of these plasticizers can be used. Among these, glycerin is preferable from the viewpoint of the effect of improving the stretchability.
- a plasticizer in the original film concerned As a minimum of content of a plasticizer in the original film concerned, 1 mass part is preferred to 100 mass parts of PVA, 3 mass parts is more preferred, and 5 mass parts is still more preferred. Stretchability is further improved by setting the content of the plasticizer to the above lower limit or more. On the other hand, as an upper limit of this content, 20 mass parts is preferred, 17 mass parts is more preferred, and 15 mass parts is still more preferred. By making content of a plasticizer below the said upper limit, it can suppress that a raw film becomes too soft, a plasticizer bleeds out on the surface, and a handling property falls.
- the lower limit of the total amount of PVA and plasticizer in the raw film is preferably 70% by mass, more preferably 75% by mass, and even more preferably 80% by mass.
- the raw film may further include a filler, a processing stabilizer such as a copper compound, a weather resistant stabilizer, a colorant, an ultraviolet light absorber, a light stabilizer, an antioxidant, and charging.
- a processing stabilizer such as a copper compound, a weather resistant stabilizer, a colorant, an ultraviolet light absorber, a light stabilizer, an antioxidant, and charging.
- Other additives, such as a speed retarder can be added as appropriate.
- an upper limit of content of additives other than PVA, a resin particle, and a plasticizer in the raw film concerned 1 mass% may be preferred, and 0.2 mass% may be more preferred.
- the content of other additives exceeds the above upper limit, the tear strength and optical properties of the resulting stretched optical film may be affected.
- the lower limit of the degree of swelling of the raw film is preferably 160%, more preferably 170%, and still more preferably 180%.
- the degree of swelling is at least the above lower limit, it is possible to suppress the progress of crystallization extremely, and it is possible to stably stretch to a high magnification.
- the upper limit of the degree of swelling is preferably 240%, more preferably 230%, and still more preferably 220%.
- the degree of swelling of the raw film is the weight obtained by immersing the raw film in distilled water at 30 ° C for 30 minutes, and the raw film dried at 105 ° C for 16 hours after being immersed in distilled water at 30 ° C for 30 minutes. It means the percentage of the value obtained by dividing by the mass of the film.
- the width of the raw film is not particularly limited, and can be determined depending on the application of the stretched optical film such as a polarizing film to be produced. It is suitable for these applications if the width of the original film is 3 m or more, in recent years, in view of the progress of large screen of liquid crystal television and liquid crystal monitor. On the other hand, when the width of the raw film is too large, it tends to be difficult to perform uniaxial stretching uniformly in the case of producing a stretched optical film by a commercially available apparatus. Therefore, the width of the raw film is preferably 7 m or less.
- the raw film can relatively easily produce a stretched optical film which is difficult to tear during production and handling. Therefore, it can be suitably used as a material of a stretched optical film such as a polarizing film or a retardation film.
- the raw film is particularly preferably used as a raw film for producing a polarizing film because a polarizing film having good polarizing performance can be easily produced.
- the method for producing the raw film of the present invention is not particularly limited, and a production method in which the thickness and width of the raw film after film formation can be made more uniform can be preferably employed.
- one or more of the above-mentioned PVA and resin particles constituting the raw film, and, if necessary, a plasticizer, other additives, and a surfactant described later may be contained in the liquid medium. It can be obtained by forming a film using the dissolved film-forming solution. Moreover, it can manufacture also using the film forming undiluted
- liquid medium examples include water, dimethylsulfoxide, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, ethylene glycol, glycerin, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, trimethylolpropane, ethylenediamine, diethylenetriamine and the like. It can be mentioned.
- liquid media can be used alone or in combination of two or more. Among these, water is preferable in terms of environmental impact and recoverability.
- the volatilization fraction of the undiluted solution (content ratio of volatile components such as liquid medium in the undiluted solution to be removed by volatilization or evaporation during film deposition) varies depending on the film forming method, film forming conditions, etc.
- the lower limit is preferably 50% by mass, more preferably 55% by mass, and still more preferably 60% by mass.
- the volatilization fraction of the membrane-forming solution is at least the above lower limit, the viscosity of the membrane-forming solution does not become too high, and filtration and degassing are smoothly carried out at the time of preparation of the membrane-forming solution. The manufacture of the film is facilitated.
- the upper limit of the volatile fraction is preferably 95% by mass, more preferably 90% by mass, and still more preferably 85% by mass.
- the volatilization fraction of the membrane-forming solution is not more than the above-mentioned upper limit, the concentration of the membrane-forming solution does not become too low, and the industrial production of the original film becomes easy.
- the membrane-forming solution preferably contains a surfactant.
- a surfactant By including the surfactant, the film forming property is improved, generation of thickness unevenness of the raw film is suppressed, and peeling of the film from a metal roll or belt used for film formation becomes easy.
- the raw film may contain a surfactant.
- the type of surfactant is not particularly limited, but from the viewpoint of releasability from metal rolls and belts, anionic surfactants and nonionic surfactants are preferred.
- the anionic surfactant is preferably, for example, a carboxylic acid type such as potassium laurate; a sulfuric acid ester type such as polyoxyethylene lauryl ether sulfate and octyl sulfate; and a sulfonic acid type such as dodecylbenzene sulfonate.
- a carboxylic acid type such as potassium laurate
- a sulfuric acid ester type such as polyoxyethylene lauryl ether sulfate and octyl sulfate
- a sulfonic acid type such as dodecylbenzene sulfonate.
- nonionic surfactants include alkyl ether types such as polyoxyethylene oleyl ether; alkyl phenyl ether types such as polyoxyethylene octyl phenyl ether; alkyl ester types such as polyoxyethylene laurate; polyoxyethylene lauryl amino ether Alkylamine type such as polyoxyethylene lauric acid amide; polypropylene glycol ether type such as polyoxyethylene polyoxypropylene ether; alkanolamide type such as lauric acid diethanolamide, oleic acid diethanolamide; polyoxyalkylene Preferred is an allyl phenyl ether type such as allyl phenyl ether.
- surfactants can be used alone or in combination of two or more.
- the lower limit of the content is preferably 0.01 parts by mass with respect to 100 parts by mass of PVA contained in the membrane-forming solution or the raw film, 0 The amount is more preferably 0.22 parts by mass, further preferably 0.05 parts by mass.
- the content of the surfactant is the above lower limit or more, the film forming property and the releasability are further improved.
- an upper limit of this content 0.5 mass part is preferred, 0.3 mass part is more preferred, and 0.1 mass part is still more preferred.
- content of surfactant is below the said upper limit, it can suppress that a surfactant bleeds out on the surface of a raw film, blocking arises, and a handling property falls.
- a film forming method at the time of forming an original film film using the film forming solution for example, a cast film forming method, an extrusion film forming method, a wet film forming method, a gel film forming method and the like can be mentioned. These film forming methods may be used alone or in combination of two or more. Among these film forming methods, the cast film forming method and the extrusion film forming method are preferable because a raw film having uniform thickness and width and good physical properties can be obtained. Drying and heat treatment can be performed on the formed raw film as required.
- the film forming solution is positioned on the most upstream side, uniformly on the circumferential surface of the rotating heated first roll (or belt). Discharge or cast. The volatile component is evaporated from one surface of the PVA film formed on the circumferential surface of the first roll (or belt) to dry the PVA film. Subsequently, the PVA film was further dried on the circumferential surface of one or a plurality of rotating heated rolls disposed downstream thereof, or was further dried by passing the PVA film through a hot air drying apparatus. After that, take up by the take-up device. Drying with a heated roll and drying with a hot air drying apparatus may be carried out in combination as appropriate.
- the stretched optical film according to an embodiment of the present invention is an optical film containing PVA oriented in a predetermined direction, such as a polarizing film or a retardation film.
- the stretched optical film may be uniaxially stretched or biaxially stretched, but is preferably uniaxially stretched.
- the stretched optical film uniaxially stretched can be suitably used as a polarizing film or the like.
- the stretched optical film may be a monolayer film or a multilayer film, but is preferably a monolayer film.
- the upper limit of the average thickness of the stretched optical film is 20 ⁇ m, preferably 18 ⁇ m, more preferably 16 ⁇ m, and still more preferably 14 ⁇ m. By the average thickness of the said stretched optical film being below the said upper limit, sufficient thickness reduction can be achieved.
- the lower limit of the average thickness is preferably 5 ⁇ m, more preferably 8 ⁇ m, and still more preferably 10 ⁇ m. By the average thickness of the said stretched optical film being more than the said minimum, tearing strength can be enlarged more.
- the stretched optical film contains PVA as a main component and resin particles.
- the lower limit of the average particle diameter of the resin particles contained in the stretched optical film is 25 nm, preferably 30 nm, and more preferably 50 nm.
- the upper limit of the average particle diameter is 150 nm, preferably 100 nm, more preferably 80 nm, and even more preferably 60 nm.
- the stretched optical film may be whitened, or optical properties such as polarization performance may be deteriorated.
- the lower limit of the content of resin particles in the stretched optical film is 1% by mass, preferably 3% by mass, and more preferably 6% by mass.
- the tear strength can be increased by setting the content of the resin particles to the above lower limit or more.
- the upper limit of the content is 25% by mass, preferably 20% by mass, and more preferably 15% by mass. When the content of the resin particles exceeds the above upper limit, clouding may occur or the optical properties may be degraded.
- the measurement of the average particle diameter and the content of the resin particles contained in the stretched optical film can be performed in the same manner as the average particle diameter and the content of the resin particles contained in the above-mentioned raw film.
- Preferred forms of PVA and resin particles contained in the stretched optical film are the same as the PVA and resin particles contained in the above-described raw film.
- the stretched optical film has a dichroic dye adsorbed on the front and back surfaces.
- a dichroic dye an iodine based dye is common.
- the lower limit of the tear strength of the stretched optical film is preferably 2N, more preferably 3N, and still more preferably 4N.
- the stretched optical film tends to tear when laminating the protective film, etc., and the production yield is lowered.
- the upper limit of the tear strength may be, for example, 20 N or 10 N.
- the polarization performance is preferably 99.99% and more preferably 99.995% as the lower limit of the degree of polarization when the transmittance is 42%. More preferably, it is 99.997%.
- the degree of polarization is less than the above lower limit, the contrast of the LCD may be lowered when used in a smartphone, a notebook computer, a liquid crystal television, a car navigation system, or the like.
- this polarizing film is usually used as a polarizing plate by laminating a protective film which is optically transparent and has mechanical strength on both sides or one side thereof.
- a protective film a cellulose triacetate (TAC) film, a cellulose acetate / butyrate (CAB) film, an acrylic film, a polyester film or the like is used.
- TAC cellulose triacetate
- CAB cellulose acetate / butyrate
- an acrylic film a polyester film or the like
- a polyester film or the like is used as an adhesive agent for bonding.
- a PVA-type adhesive agent a PVA-type adhesive agent, an ultraviolet curable adhesive agent, etc.
- a PVA-type adhesive agent is preferable.
- a retardation film, a viewing angle improvement film, a brightness enhancement film, etc. may be further bonded to the polarizing plate obtained as described above.
- the stretched optical film of this invention can also be used as said retardation film.
- the polarizing plate can be used as a component of an LCD by bonding it to a glass substrate after being coated with an acrylic or other pressure-sensitive adhesive.
- the stretched optical film according to an embodiment of the present invention can be obtained by the production method including the step of stretching the raw film described above.
- stretching optical film is a polarizing film is demonstrated.
- the raw film may be subjected to swelling treatment, dyeing treatment, uniaxial stretching treatment, and if necessary, crosslinking treatment, fixing treatment, washing treatment, drying.
- the method include treatment and heat treatment.
- the order of the treatments such as swelling treatment, dyeing treatment, crosslinking treatment, uniaxial stretching, and fixation treatment is not particularly limited, and two or more treatments may be performed simultaneously. Also, one or more of each treatment may be performed twice or more.
- the swelling treatment can be carried out by immersing the raw film in water.
- 20 ° C is preferred, 22 ° C is more preferred, and 25 ° C is still more preferred.
- 40 ° C is preferred, 38 ° C is more preferred, and 35 ° C is still more preferred.
- 0.1 minute is preferable, and 0.5 minute is more preferable.
- 5 minutes are preferable and 3 minutes are more preferable.
- the water at the time of immersing in water is not limited to a pure water, The aqueous solution which various components melt
- the dyeing process can be carried out by contacting the original film with a dichroic dye.
- a dichroic dye an iodine based dye is generally used.
- staining process you may be any stage before uniaxial stretching processing, at the time of uniaxial stretching processing, and after uniaxial stretching processing.
- the dyeing process is generally carried out by immersing the raw film as a dyeing bath in a solution containing iodine-potassium iodide (in particular, an aqueous solution).
- the concentration of iodine in the dye 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.
- 20 degreeC is preferable and, as for the minimum of the temperature of a dyeing
- 50 degreeC is preferable and, as for the upper limit of this temperature, 40 degreeC is more preferable.
- the crosslinking treatment is preferably performed before the uniaxial stretching treatment.
- the crosslinking treatment can be carried out by immersing the raw film in an aqueous solution containing a crosslinking agent.
- a crosslinking agent 1 type (s) or 2 or more types of boron inorganic compounds, such as boric acid, borates, such as borax, can be used.
- the lower limit of the concentration of the crosslinking agent in the aqueous solution containing the crosslinking agent is preferably 1% by mass, more preferably 2% by mass, and still more preferably 3% by mass.
- the upper limit of the concentration is preferably 15% by mass, more preferably 7% by mass, and still more preferably 6% by mass.
- concentration of the crosslinking agent is in the above range, sufficient stretchability can be maintained.
- the aqueous solution containing the crosslinking agent may contain an auxiliary such as potassium iodide. 20 degreeC is preferable and, as for the minimum of the temperature of the aqueous solution containing a crosslinking agent, 25 degreeC is more preferable. On the other hand, 50 degreeC is preferable and, as for the upper limit of this temperature, 40 degreeC is more preferable. By setting the temperature within the above range, crosslinking can be efficiently performed.
- the uniaxial stretching treatment 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 of boric acid or in the above-mentioned dyeing bath or in a fixed treatment bath described later.
- dry stretching uniaxial stretching may be performed at room temperature, or uniaxial stretching may be performed while heating, or uniaxial stretching in air using a raw film after water absorption. You may Among these, a wet stretching method is preferable, and uniaxial stretching in a boric acid aqueous solution is more preferable.
- the lower limit of the boric acid concentration of the aqueous boric acid solution is preferably 0.5% by mass, more preferably 1.0% by mass, and still more preferably 1.5% by mass. On the other hand, 6.0 mass% is preferable, as for the upper limit of this boric acid concentration, 5.0 mass is more preferable, and 4.0 mass% is more preferable.
- the boric acid aqueous solution may contain potassium iodide, and the concentration thereof is preferably 0.01% by mass or more and 10% by mass or less.
- 30 degreeC is preferable, as for the minimum of the extending
- 90 ° C. is preferable, 80 ° C. is more preferable, and 70 ° C. is more preferable as the upper limit of the stretching temperature.
- the lower limit of the draw ratio in uniaxial stretching is preferably 5 times, more preferably 6 times, from the viewpoint of the polarization performance of the obtained polarizing film.
- the upper limit in particular of a draw ratio is not restrict
- the direction of uniaxial stretching in the case of uniaxial stretching on a long raw film is not particularly limited.
- uniaxial stretching treatment in the long direction or transverse uniaxial stretching treatment or so-called oblique stretching treatment can be adopted, uniaxial stretching treatment in the long direction is preferable because a polarizing film having excellent polarization performance can be obtained.
- the uniaxial stretching treatment in the longitudinal direction can be performed by changing the circumferential speed between the respective rolls using a stretching apparatus provided with a plurality of rolls parallel to each other.
- the transverse uniaxial stretching treatment can be performed using a tenter-type stretching machine.
- the polarizing film it is preferable to carry out a fixing treatment after the uniaxial stretching treatment in order to strengthen the adsorption of the dichroic dye (iodine-based dye etc.) to the raw film.
- a fixing process bath used for a fixing process the aqueous solution containing 1 type, or 2 or more types of boron inorganic compounds, such as a boric acid and borax, can be used.
- an iodine compound or a metal compound may be added to the fixing treatment bath. 2 mass% is preferable and, as for the minimum of the density
- the lower limit of the temperature of the fixed treatment bath is preferably 15 ° C.
- 60 degreeC is preferable and, as for the upper limit of this temperature, 40 degreeC is more preferable.
- the washing treatment is generally performed by immersing the raw film in water or the like.
- water and the like used for the washing treatment contain an auxiliary agent such as potassium iodide from the viewpoint of improving the polarization performance.
- the concentration of iodide such as potassium iodide is preferably 0.5% by mass or more and 10% by mass or less.
- the lower limit of the temperature of water and the like used for the washing treatment is generally 5 ° C., preferably 10 ° C., and more preferably 15 ° C.
- the upper limit of this temperature is generally 50 ° C., preferably 45 ° C., and more preferably 40 ° C. It is not preferable that the temperature of water or the like is too low from the economic point of view. On the other hand, if the temperature of water or the like is too high, the polarization performance may be degraded.
- drying temperature As a minimum of drying temperature, 30 degreeC is preferable and 50 degreeC is more preferable. On the other hand, as an upper limit of drying temperature, 150 degreeC is preferable and 130 degreeC is more preferable. By drying at a temperature within the above range, it is easy to obtain a polarizing film having excellent dimensional stability.
- the heat treatment is a treatment to further heat the polarizing film having a moisture content of 5% or less after the drying treatment to improve the dimensional stability of the polarizing film.
- the conditions in particular of heat processing are not restrict
- the heat treatment is performed at a temperature lower than 60 ° C., the dimensional stabilization effect by the heat treatment is insufficient.
- the heat treatment is performed at a temperature higher than 150 ° C., yellowing may be intensely generated in the polarizing film.
- the raw film, the stretched optical film, and the method for producing the stretched optical film of the present invention are not limited to the above embodiment.
- a stretched optical film and a method for producing the same have been described focusing on the case where the stretched optical film is a polarizing film
- the stretched optical film is not limited to a polarizing film.
- a stretched optical film other than a polarizing film such as a retardation film is also within the scope of the present invention, and can be produced by a production method comprising the step of stretching the raw film of the present invention.
- the manufacturing method of the retardation film as one Embodiment of this invention can be performed using a conventionally well-known method except extending
- the refractive index 1.33 of water, the viscosity 0.89 cP of water, and the dielectric constant 78.3 of water were used as values of the refractive index, viscosity, and relative dielectric constant of the measurement solvent.
- the noise cut level was set to 0.3%, the number of integrations was 70, and the pinhole was set to 50 ⁇ m.
- filter mass B primary filtration of the above aqueous solution was performed using one of them (filter mass B).
- the primary filtrate was recovered, and secondary filtration was further performed using a second membrane filter (filter mass B ′) with a pore diameter of 0.025 ⁇ m.
- the secondary filtrate was recovered, and third filtration was performed using a third membrane filter (filter mass B ′ ′) with a pore diameter of 0.025 ⁇ m.
- three pieces of membrane filters with a pore diameter of 0.025 ⁇ m used for primary filtration to tertiary filtration were dried together with the filtrate for 16 hours at 60 ° C./vacuum, and the total mass (C (g)) was measured.
- the average particle size was determined by the scattering method.
- the refractive index 1.33 of water, the viscosity 0.89 cP of water, and the dielectric constant 78.3 of water were used as values of the refractive index, viscosity, and relative dielectric constant of the measurement solvent.
- the noise cut level was set to 0.3%, the number of integrations was 70, and the pinhole was set to 50 ⁇ m.
- a polarizing film having a size of 33 mm in the stretching direction and 20 mm in the direction perpendicular to the stretching direction was sandwiched between two stainless steel frames having an outer size of 33 mm ⁇ 27 mm, an inner size of 20 mm ⁇ 15 mm, and a thickness of 1 mm.
- the long side direction of the outer dimension of the stainless steel frame and the long side direction of the inner dimension are the same direction, and the polarizing film was sandwiched such that the stretching direction of the polarizing film and the long side direction of the stainless steel frame were parallel.
- a polarizing film located at the center of the stainless steel frame was pierced at a speed of 1 mm / min, and the maximum load at this time was measured. The measurement was carried out four times, the average value of the maximum load was calculated, and the average value was taken as the tear strength.
- Ts1 and Ts2 were averaged using the following calculation formula (11), and it was set as the transmittance
- Ts (Ts1 + Ts2) / 2 (11)
- n-methylcyclohexylamine added from the middle of the cylinder was changed to 0.072 kg / hour (an amount of 40 moles per 100 moles of methyl methacrylate units in methyl methacrylate-n-butyl acrylate copolymer)
- a methacrylic anhydride-n-butyl acrylate copolymer 2 was obtained in the same manner as described above except for the above.
- Preparation Example 2 Preparation of Resin Particles Made of Methacrylic Acid-N-Butyl Acrylate-Methacrylic Acid Triblock Copolymer
- the acid anhydride is converted to a carboxy group by crushing to 20 mm 3 or less and soaking in hot water at 80 ° C. for 24 hours, and methacrylic acid-n-butyl acrylic copolymer 1 (MAA-BA copolymer 1) And Next, the MAA-BA copolymer 1 was taken out by filtration and dried, and then dissolved using methanol as a solvent so as to have a solid content concentration of 10% by mass.
- the resulting MAA-BA copolymer 1 / methanol solution is added dropwise to distilled water of the same mass as the methanol used to dissolve MAA-BA copolymer 1, and from MAA-BA copolymer 1 A dispersion of resin particles was obtained. Thereafter, the dispersion is heated to 60 ° C. and treated under reduced pressure so as not to boil so as to remove methanol, and methacrylic acid-acrylic acid n-butyl-methacrylic acid triacetate having a solid content concentration of 10% by mass. An aqueous dispersion of resin particles 1 consisting of block copolymer 1 (MAA-BA-MAA triblock copolymer 1) was obtained.
- the MAA-BA-MAA triblock copolymer 1 is a thermoplastic elastomer.
- the MAA-BA-MAA triblock copolymer 2 is a thermoplastic elastomer.
- Example 1 100 parts by mass of PVA (saponification degree 99.3 mol%, polymerization degree 2400, ethylene modification amount 2.5 mol%), 10 parts by mass of glycerin as a plasticizer, sodium polyoxyethylene lauryl ether sulfate as a surfactant
- An aqueous solution containing 10 parts by mass of PVA containing 1 part by mass and 5 parts by mass of the above-mentioned resin particle 1 (MAA-BA-MAA triblock copolymer 1) is prepared and used as a film forming solution. Using. The film-forming stock solution was dried on a metal roll at 80 ° C., and the obtained PVA film was heat-treated at a temperature of 120 ° C.
- the iodine concentration of the dyeing treatment bath was appropriately adjusted so that the transmittance Ts (%) of the obtained polarizing film was 42%.
- an aqueous solution (crosslinking treatment bath) temperature 30 ° C.
- it is 1.2 times (totally 2.times.) In the length direction.
- Uniaxially stretched to 7 times).
- an aqueous solution (uniaxial stretching treatment bath) containing 4% by mass of boric acid and 6% by mass of potassium iodide uniaxial stretching is performed up to a total of 6.2 times (total stretching ratio) in the length direction did.
- Example 2 An original film and a polarizing film were produced in the same manner as in Example 1 except that the mixing amount of the resin particles 1 was 10 parts by mass with respect to 100 parts by mass of PVA. Average thickness of the obtained raw film, average particle diameter of resin particles in the raw film, content of resin particles in the raw film, average thickness of the polarizing film, average particle size of the resin particles in the polarizing film, The content of resin particles in the polarizing film, the tear strength of the polarizing film, and the polarizing performance were measured or evaluated. The results are shown in Table 1.
- Example 3 The raw film and the polarizing film were produced by the method similar to Example 1 except the mixing amount of the said resin particle 1 with respect to 100 mass parts of PVA having been 20 mass parts. Average thickness of the obtained raw film, average particle diameter of resin particles in the raw film, content of resin particles in the raw film, average thickness of the polarizing film, average particle size of the resin particles in the polarizing film, The content of resin particles in the polarizing film, the tear strength of the polarizing film, and the polarizing performance were measured or evaluated. The results are shown in Table 1.
- Example 4 An original film and a polarizing film were produced in the same manner as in Example 1 except that the resin particles 1 added to the membrane forming solution were changed to the above resin particles 2 (MAA-BA-MAA triblock copolymer 2). . Average thickness of the obtained raw film, average particle diameter of resin particles in the raw film, content of resin particles in the raw film, average thickness of the polarizing film, average particle size of the resin particles in the polarizing film, The content of resin particles in the polarizing film, the tear strength of the polarizing film, and the polarizing performance were measured or evaluated. The results are shown in Table 1.
- Example 5 A raw film and a polarizing film were produced in the same manner as in Example 3 except that the resin particles 1 added to the membrane forming solution were changed to the above resin particles 2. Average thickness of the obtained raw film, average particle diameter of resin particles in the raw film, content of resin particles in the raw film, average thickness of the polarizing film, average particle size of the resin particles in the polarizing film, The content of resin particles in the polarizing film, the tear strength of the polarizing film, and the polarizing performance were measured or evaluated. The results are shown in Table 1.
- Example 6 An original film and a polarizing film were produced in the same manner as in Example 3 except that the resin particles 1 added to the membrane forming solution were changed to Taisei Fine Chemical's "WAN-6000" (resin particles composed of urethane resin). Average thickness of the obtained raw film, average particle diameter of resin particles in the raw film, content of resin particles in the raw film, average thickness of the polarizing film, average particle size of the resin particles in the polarizing film, The content of resin particles in the polarizing film, the tear strength of the polarizing film, and the polarizing performance were measured or evaluated. The results are shown in Table 1.
- Comparative Example 1 A raw film and a polarizing film were produced in the same manner as in Example 1 except that the resin particles 1 were not added to the membrane-forming stock solution. The average thickness of the obtained raw film, the average thickness of the polarizing film, the tear strength of the polarizing film, and the polarizing performance were measured or evaluated. The results are shown in Table 1.
- Comparative Example 2 A raw film and a polarizing film were produced in the same manner as in Example 1 except that the mixing amount of the resin particles 1 was 40 parts by mass with respect to 100 parts by mass of PVA. Average thickness of the obtained raw film, average particle diameter of resin particles in the raw film, content of resin particles in the raw film, average thickness of the polarizing film, average particle size of the resin particles in the polarizing film, The content of resin particles in the polarizing film, the tear strength of the polarizing film, and the polarizing performance were measured or evaluated. The results are shown in Table 1.
- Comparative Example 3 The raw material was prepared in the same manner as in Example 3 except that resin particle 1 added to the membrane forming solution was changed to “PE-1304” (resin particle made of styrene acrylic resin, average particle diameter published by manufacturer 250 nm) manufactured by Starlight PMC. I tried to make anti-film and polarizing film. However, the production of the polarizing film and various evaluations were stopped because the raw film became white and cloudy.
- PE-1304 resin particle made of styrene acrylic resin, average particle diameter published by manufacturer 250 nm
- Comparative Example 4 The raw material was prepared in the same manner as in Example 3 except that resin particle 1 added to the membrane stock solution was changed to “Snowtex ST-50” (silica particle, manufacturer published average particle diameter 20-25 nm) of Nissan Chemical Industries, Ltd. I tried to make anti-film and polarizing film. However, the production of the polarizing film and various evaluations were stopped because the raw film became white and cloudy.
- Snowtex ST-50 sica particle, manufacturer published average particle diameter 20-25 nm
- Comparative Example 5 A raw film and a polarizing film were produced in the same manner as in Example 1 except that polyacrylic acid (degree of polymerization: 2000) of Wako Pure Chemical Industries, Ltd. was added to the film forming solution instead of the resin particles 1. Average thickness of the obtained raw film, average particle diameter of resin particles in the raw film, content of resin particles in the raw film, average thickness of the polarizing film, average particle size of the resin particles in the polarizing film, The content of resin particles in the polarizing film, the tear strength of the polarizing film, and the polarizing performance were measured or evaluated. The results are shown in Table 1. Polyacrylic acid was not present as particles in the film and was compatible with PVA.
- Comparative Example 6 A raw film and a polarizing film were produced in the same manner as in Comparative Example 1 except that 0.0316% by mass of sodium ascorbate was added to the washing treatment bath. The average thickness of the obtained raw film, the average thickness of the polarizing film, the tear strength of the polarizing film, and the polarizing performance were measured or evaluated. The results are shown in Table 1.
- Comparative Example 7 An original film and a polarizing film were produced in the same manner as in Comparative Example 1 except that stretching was performed so that the draw ratio (total draw ratio) was 4 times in the entire uniaxial drawing treatment bath. The average thickness of the obtained raw film, the average thickness of the polarizing film, the tear strength of the polarizing film, and the polarizing performance were measured or evaluated. The results are shown in Table 1.
- Comparative Example 8 A raw film and a polarizing film were produced in the same manner as in Comparative Example 1 except that the average thickness of the raw film was 40 ⁇ m. The average thickness of the obtained raw film, the average thickness of the polarizing film, the tear strength of the polarizing film, and the polarizing performance were measured or evaluated. The results are shown in Table 1.
- Comparative Example 9 A raw film and a polarizing film were produced in the same manner as in Comparative Example 1 except that the average thickness of the raw film was changed to 60 ⁇ m. The average thickness of the obtained raw film, the average thickness of the polarizing film, the tear strength of the polarizing film, and the polarizing performance were measured or evaluated. The results are shown in Table 1.
- MAA-BA-MAA triblock copolymer 1 is “methacrylic acid-acrylic acid n-butyl-methacrylic acid triblock copolymer 1” and MAA-BA-MAA triblock copolymer 2 is “ “Methacrylic acid-acrylic acid n-butyl-methacrylic acid triblock copolymer 2” is shown respectively. Further, the comprehensive judgments A to C shown in the above Table 1 are based on the following criteria.
- A Average thickness of polarizing film 20 ⁇ m or less, tearing strength 2N or more, and polarization degree of more than 99.994%
- B Polarization film average thickness 20 ⁇ m or less, tearing strength 2N or more, and polarization degree 99.990% or more, 99.994% C below: other than the above A and B
- the polarizing films obtained from the base films of Examples 1 to 6 are thin, have high tear strength, and have high polarization performance as optical characteristics.
- Comparative Examples 1 to 9 it was not possible to obtain a thin polarizing film having high tear strength and high polarization performance.
- the disadvantage that the tearing strength is less than 2 N is likely to occur when trying to produce a stretched optical film using an original film having an average thickness of 45 ⁇ m or less It can be said that it is an issue.
- the raw film of the present invention can be suitably used as a material such as a polarizing film which is a constituent material of LCD.
- stretching optical film can be used suitably as a polarizing film or its manufacturing method.
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Abstract
Description
[1]平均厚みが45μm以下であり、主成分であるビニルアルコール系重合体と、平均粒径が25nm以上150nm以下の樹脂粒子とを含有し、上記樹脂粒子の含有量が1質量%以上25質量%以下である延伸光学フィルム製造用の原反フィルム。
[2]上記樹脂粒子が重合体を含有し、上記重合体が、ヒドロキシ基を含む基を有する構造単位を備える[1]の原反フィルム。
[3][1]又は[2]の原反フィルムを延伸する工程を備える延伸光学フィルムの製造方法。
[4]平均厚みが20μm以下であり、主成分であるビニルアルコール系重合体と、平均粒径が25nm以上150nm以下の樹脂粒子とを含有し、上記樹脂粒子の含有量が1質量%以上25質量%以下である延伸光学フィルム。
本発明の一実施形態に係る原反フィルムは、延伸光学フィルムの製造に用いられるフィルムである。すなわち、当該原反フィルムは、偏光フィルムや位相差フィルム等の延伸光学フィルムの材料となるフィルムである。当該原反フィルムを延伸することにより、延伸光学フィルムが得られる。
当該原反フィルムの平均厚みの上限は、45μmであり、40μmが好ましく、35μmがより好ましく、30μmがさらに好ましい。当該原反フィルムの平均厚みが上記上限以下であることで、薄型の延伸光学フィルムを得ることができる。一方、この平均厚みの下限としては、5μmが好ましく、10μmがより好ましく、15μmがさらに好ましく、20μmがよりさらに好ましい。当該原反フィルムの平均厚みが上記下限以上であることで、得られる延伸光学フィルムの裂け強度をより大きくすることができる。
当該原反フィルムは、主成分としてPVA(ビニルアルコール系重合体)を含有する。なお、主成分とは、質量基準で最も含有量の大きい成分をいう(以下、同様である。)。PVAは、ビニルアルコール単位(-CH2-CH(OH)-)を構造単位として有する重合体である。PVAは、ビニルアルコール単位の他、ビニルエステル単位やその他の単位を有していてもよい。
エチレン、プロピレン、1-ブテン、イソブテン等の炭素数2~30のα-オレフィン;
(メタ)アクリル酸又はその塩;
(メタ)アクリル酸メチル、(メタ)アクリル酸エチル、(メタ)アクリル酸n-プロピル、(メタ)アクリル酸i-プロピル、(メタ)アクリル酸n-ブチル、(メタ)アクリル酸i-ブチル、(メタ)アクリル酸t-ブチル、(メタ)アクリル酸2-エチルへキシル、(メタ)アクリル酸ドデシル、(メタ)アクリル酸オクタデシル等の(メタ)アクリル酸エステル;
(メタ)アクリルアミド;
N-メチル(メタ)アクリルアミド、N-エチル(メタ)アクリルアミド、N,N-ジメチル(メタ)アクリルアミド、ジアセトン(メタ)アクリルアミド、(メタ)アクリルアミドプロパンスルホン酸又はその塩、(メタ)アクリルアミドプロピルジメチルアミン又はその塩、N-メチロール(メタ)アクリルアミド又はその誘導体等の(メタ)アクリルアミド誘導体;
N-ビニルホルムアミド、N-ビニルアセトアミド、N-ビニルピロリドン等のN-ビニルアミド;
メチルビニルエーテル、エチルビニルエーテル、n-プロピルビニルエーテル、i-プロピルビニルエーテル、n-ブチルビニルエーテル、i-ブチルビニルエーテル、t-ブチルビニルエーテル、ドデシルビニルエーテル、ステアリルビニルエーテル等のビニルエーテル;
(メタ)アクリロニトリル等のシアン化ビニル;
塩化ビニル、塩化ビニリデン、フッ化ビニル、フッ化ビニリデン等のハロゲン化ビニル;
酢酸アリル、塩化アリル等のアリル化合物;
マレイン酸、又はその塩、エステル若しくは酸無水物;
イタコン酸、又はその塩、エステル若しくは酸無水物;
ビニルトリメトキシシラン等のビニルシリル化合物;
不飽和スルホン酸などを挙げることができる。
当該原反フィルムは、樹脂粒子を含有する。当該原反フィルムは、所定サイズ及び所定量の樹脂粒子を含有することにより、得られる延伸光学フィルムの裂け強度を大きくすることができる。このような効果が生じる理由は定かでは無いが、当該原反フィルムから製造した延伸光学フィルムが裂けた場所の断面を観察したところ、断面が荒くなっていたことから、フィルム中に分散している微細な樹脂粒子が裂けの伝播を抑制することで、裂け強度が大きくなったものと推測される。
(メタ)アクリル酸ヒドロキシメチル、(メタ)アクリル酸2-ヒドロキシエチル、(メタ)アクリル酸2-ヒドロキシプロピル、(メタ)アクリル酸ヒドロキシフェニル等のヒドロキシ基を有する(メタ)アクリル酸エステル、2-ヒドロキシエチルビニルエーテル、4-ヒドロキシブチルビニルエーテル等のヒドロキシ基を有するビニルエーテル、3-ブテン-1-オール、4-ペンテン-1-オール、5-ヘキセン-1-オール等の不飽和アルコール、その他ビニルフェノール等、ヒドロキシ基を有する単量体;
(メタ)アクリル酸、クロトン酸、マレイン酸、イタコン酸、これらの塩、これらの無水物等のカルボキシ基を有する単量体;
エチレンスルホン酸、アリルスルホン酸、メタアリルスルホン酸、これらの塩等のスルホ基を有する単量体等を挙げることができる。
当該原反フィルムは、可塑剤をさらに含むことができる。当該原反フィルムが可塑剤を含むことにより、取扱性や延伸性の向上等を図ることができる。好ましい可塑剤としては、多価アルコールが挙げられ、具体例としては、エチレングリコール、グリセリン、プロピレングリコール、ジエチレングリコール、ジグリセリン、トリエチレングリコール、テトラエチレングリコール、トリメチロールプロパンなどが挙げられる。これらの可塑剤は、1種又は2種以上を用いることができる。これらの中でも、延伸性の向上効果の点からグリセリンが好ましい。
当該原反フィルムには、PVA、樹脂粒子及び可塑剤以外に、さらに充填剤、銅化合物などの加工安定剤、耐候性安定剤、着色剤、紫外線吸収剤、光安定剤、酸化防止剤、帯電防止剤、難燃剤、他の熱可塑性樹脂、潤滑剤、香料、消泡剤、消臭剤、増量剤、剥離剤、離型剤、補強剤、架橋剤、防かび剤、防腐剤、結晶化速度遅延剤などの他の添加剤を、必要に応じて適宜配合できる。
本発明の原反フィルムの製造方法は特に限定されず、製膜後の原反フィルムの厚み及び幅がより均一になる製造方法を好ましく採用することができる。例えば、原反フィルムを構成する上記PVA及び樹脂粒子、並びに必要に応じてさらに、可塑剤、その他の添加剤、及び後述する界面活性剤等のうちの1種又は2種以上が液体媒体中に溶解した製膜原液を用いて、製膜することにより得ることができる。また、必要に応じて、PVAを溶融した製膜原液を用いても製造することができる。製膜原液において、樹脂粒子は均一に混合されていることが好ましい。また、製膜原液が、可塑剤、その他の添加剤及び界面活性剤の少なくとも1種を含有する場合には、それらの成分が均一に混合されていることが好ましい。
本発明の一実施形態に係る延伸光学フィルムは、偏光フィルムや位相差フィルム等、所定方向に配向したPVAを含む光学フィルムである。当該延伸光学フィルムは、一軸延伸されていてもよく、二軸延伸されていてもよいが、一軸延伸されていることが好ましい。一軸延伸された当該延伸光学フィルムは、偏光フィルム等として好適に用いることができる。当該延伸光学フィルムは、単層フィルムであっても、多層フィルムであってもよいが、単層フィルムであることが好ましい。
当該延伸光学フィルムの平均厚みの上限は、20μmであり、18μmが好ましく、16μmがより好ましく、14μmがさらに好ましい。当該延伸光学フィルムの平均厚みが上記上限以下であることで、十分な薄型化を図ることができる。一方、この平均厚みの下限としては、5μmが好ましく、8μmがより好ましく、10μmがさらに好ましい。当該延伸光学フィルムの平均厚みが上記下限以上であることで、裂け強度をより大きくすることができる。
当該延伸光学フィルムは、主成分であるPVAと樹脂粒子とを含有する。
本発明の一実施形態に係る延伸光学フィルムは、上述した当該原反フィルムを延伸する工程を備える製造方法によって得ることができる。以下、当該延伸光学フィルムが偏光フィルムである場合の具体的な製造方法について説明する。
本発明の原反フィルム、延伸光学フィルム、及び延伸光学フィルムの製造方法は、上記実施の形態に限定されるものではない。例えば、延伸光学フィルム及びその製造方法としては、延伸光学フィルムが偏光フィルムである場合を中心に説明したが、延伸光学フィルムは偏光フィルムに限定されるものではない。例えば、位相差フィルム等の偏光フィルム以外の延伸光学フィルムも、本発明の範囲内であり、本発明の原反フィルムを延伸する工程を備える製造方法によって製造することができる。本発明の一実施形態としての位相差フィルムの製造方法は、本発明の原反フィルムを延伸すること以外は、従来公知の方法を用いて行うことができる。
原反フィルムの中央部から幅方向に3cm間隔で厚みを測定し、その平均値を原反フィルムの平均厚みとした。厚みの測定は、シルバック社の「デジタルマイクロインジケータS229」と小野測器社の「ゲージスタンドST-022」を用いて行った。
原反フィルム2gを熱水に入れ、濃度が2質量%になるように調製して95℃で4時間撹拌し、原反フィルムを溶解させた。熱水の水温を25℃まで冷却した後、水を加えて散乱光強度が適切になるように調整した。この分散液に対して、大塚電子社のゼータ電位・粒径測定システム「ELS-Z2」を用いて、25℃の環境下で動的光散乱を測定し、キュムラント解析を行うことで動的光散乱法による平均粒径を求めた。なお、測定溶媒の屈折率、粘度、比誘電率の値として、水の屈折率1.33、水の粘度0.89cP、水の比誘電率78.3を用いた。また、ノイズカットレベルは0.3%、積算回数は70回、ピンホールは50μmに設定した。
20℃/50%RHで16時間調湿した原反フィルムをおよそ0.1g切り取り、精秤(A(g))した。その後、およそ2質量%になるように95℃の熱水を加えて4時間撹拌し、原反フィルムを溶解させた。熱水の水温を25℃まで冷却した後、水を加えて40倍に希釈した水溶液とした。次に孔径0.025μmのメンブレンフィルター(メルク社の「MF-ミリポア」)を3枚用意し、それぞれのフィルター質量(B、B’、B’’(g))を測定した。次に、そのうちの1枚(フィルター質量B)を用いて、上記水溶液の一次ろ過を行った。その一次ろ過液を回収し、更に、2枚目の孔径0.025μmのメンブレンフィルター(フィルター質量B’)を用いて二次ろ過を行った。更に、その二次ろ過液を回収し、3枚目の孔径0.025μmのメンブレンフィルター(フィルター質量B’’)を用いて三次ろ過を行った。その後、一次ろ過から三次ろ過に使用した3枚の孔径0.025μmのメンブレンフィルターを、ろ物とともに60℃/真空下で16時間乾燥し、その総質量(C(g))を測定した。その後、下記計算式(1)を用いて、三枚の孔径0.025μmのメンブレンフィルターで捕捉された成分、すなわち樹脂粒子の質量(D(g))を算出した。次いで、下記計算式(2)を用いて、原反フィルム中の樹脂粒子の含有量を算出した。
捕捉された成分(樹脂粒子)の質量D(g)
=C-(B+B’+B’’)・・・(1)
原反フィルム中の樹脂粒子の含有量(質量%)
=(D/A)×100 ・・・(2)
偏光フィルムの中央部から、幅方向に15mm間隔で厚みを測定し、その平均値を偏光フィルムの平均厚みとした。厚みの測定は、小野測器社の「デジタルゲージカウンターDG-5100」、小野測器社の「リニアゲージセンサーGS-3813」、及び小野測器社の「ゲージスタンドST-0230」を用いて行った。
約10gの偏光フィルムを1cm×1cmの大きさに切り、蒸留水200gとともに500mLのガラスビーカーに入れた。その後、3.4cm×0.8cm×0.7cmの大きさの撹拌子を用いて300rpmの速さで撹拌しながら、95℃に昇温し、24時間撹拌し、偏光フィルムを溶解させた。25℃まで冷却した後、水を加えて散乱光強度が適切になるように調整した。この分散液に対して、大塚電子社のゼータ電位・粒径測定システム「ELS-Z2」を用いて、25℃の環境下で動的光散乱を測定し、キュムラント解析を行うことで動的光散乱法による平均粒径を求めた。なお、測定溶媒の屈折率、粘度、比誘電率の値として、水の屈折率1.33、水の粘度0.89cP、水の比誘電率78.3を用いた。また、ノイズカットレベルは0.3%、積算回数は70回、ピンホールは50μmに設定した。
約10gの偏光フィルムの質量(E(g))を精秤した後、1cm×1cmの大きさに切り、蒸留水200gとともに500mLのガラスビーカーに入れた。その後、3.4cm×0.8cm×0.7cmの大きさの撹拌子を用いて300rpmの速さで撹拌しながら、95℃に昇温し、24時間撹拌し、偏光フィルムを溶解させた。25℃まで冷却した後、水を加えて濃度が約0.05質量%となるように水溶液を調整した。次に、孔径0.025μmのメンブレンフィルター(メルク社の「MF-ミリポア」)を3枚用意し、それぞれのフィルター質量(F、F’、F’’(g))を測定した。次に、そのうちの1枚(フィルター質量F)を用いて調整後の水溶液に対して一次ろ過を行った。一次ろ過液を回収し、更に、2枚目の孔径0.025μmのメンブレンフィルター(フィルター質量F’)を用いて二次ろ過を行った。更に、二次ろ過液を回収し、3枚目の孔径0.025μmのメンブレンフィルター(フィルター質量F’’)で三次ろ過を行った。その後、一次ろ過から三次ろ過に使用した孔径0.025μmのメンブレンフィルターをろ物とともに60℃/真空下で16時間乾燥し、その総質量(G(g))を測定した。その後、下記計算式(3)を用いて、三枚の孔径0.025μmのメンブレンフィルターで捕捉された成分、すなわち樹脂粒子の質量(H(g))を算出し、下記計算式(4)を用いて、偏光フィルム中の樹脂粒子の含有量を算出した。
捕捉された成分(樹脂粒子)の質量H(g)
=G-(F+F’+F’’)・・・(3)
偏光フィルム中の樹脂粒子の含有量(質量%)
=(H/E)×100 ・・・(4)
延伸方向に33mm、延伸方向と垂直な方向に20mmの大きさの偏光フィルムを、外寸33mm×27mm、内寸20mm×15mm、厚み1mmのステンレス枠2枚の間に挟んだ。なお、ステンレス枠の外寸の長辺方向と内寸の長辺方向は同じ方向であり、偏光フィルムの延伸方向とステンレス枠の長辺方向とが平行になるように偏光フィルムを挟んだ。次にステンレス枠の長辺の両端の2箇所をクリップで挟んで留めて偏光フィルムを固定し、測定試料とした。なお、偏光フィルムは20℃/20%RHで18時間調湿したものを使用した。次に島津製作所の卓上形精密万能試験機「オートグラフAGS-J」の下のつかみ具に上記測定試料を固定した。一方、上記試験器の上のつかみ具に先端形状が短辺1mm、長辺5mmの矩形である突き刺し治具を、その長辺が偏光フィルムの延伸方向に平行となるように固定した。そして、ステンレス枠の中央に位置する偏光フィルムを速度1mm/分で突き刺し、このときの最大荷重を測定した。測定は4回行い、最大荷重の平均値を計算し、その平均値を裂け強度とした。
(透過率Tsの測定)
偏光フィルムの中央部から、偏光フィルムの延伸方向に2cmの長さのサンプルを2枚採取した。1枚のサンプルについて、積分球付き分光光度計(日本分光社の「V7100」)を用いて、JIS Z 8722(物体色の測定方法)に準拠し、C光源、2°視野の可視光領域の視感度補正を行い、長さ方向に対して+45°傾けた場合の光の透過率と-45°傾けた場合の光の透過率を測定して、それらの平均値Ts1(%)を求めた。もう1枚のサンプルについても同様にして、+45°傾けた場合の光の透過率と-45°傾けた場合の光の透過率を測定して、それらの平均値Ts2(%)を求めた。下記計算式(11)を用いて、Ts1とTs2を平均し、偏光フィルムの透過率Ts(%)とした。
Ts=(Ts1+Ts2)/2・・・(11)
上記透過率Tsの測定で使用した2枚のサンプルについて、その延伸方向がお互いに直交するように重ねた場合の光の透過率T⊥(%)と、その延伸方向が平行になるように重ねた場合の光の透過率T//(%)を測定した。この測定は、積分球付き分光光度計(日本分光社の「V7100」)を用いて、JIS Z 8722(物体色の測定方法)に準拠し、C光源、2°視野の可視光領域の視感度補正を行って実施した。測定したT//(%)及びT⊥(%)から、下記計算式(12)を用いて、偏光度V(%)を求めた。
V={(T//-T⊥)/(T//+T⊥)}1/2×100・・・(12)
二軸押出機(パーカーコーポレーション社製)に、ホッパーからメタクリル酸メチル-アクリル酸n-ブチル共重合体(クラリティ(登録商標)LA2140、株式会社クラレ製、メタクリル酸メチル単位24質量%)を0.66kg/時で供給し、シリンダー途中からn-メチルシクロヘキシルアミンを0.18kg/時(メタクリル酸メチル-アクリル酸n-ブチル共重合体中のメタクリル酸メチル単位100モルに対して100モルとなる量)で供給し、シリンダー温度220℃、スクリュウ回転数100rpmで溶融混練した。これにより、メタクリル酸無水物-アクリル酸n-ブチル共重合体1を得た。
製造例1にて得られたメタクリル酸無水物-アクリル酸n-ブチル共重合体1を20mm3以下に粉砕し、80℃の熱水に24時間浸漬することで酸無水物をカルボキシ基に変換し、メタクリル酸-アクリル酸n-ブチル共重合体1(MAA-BA共重合体1)とした。次にMAA-BA共重合体1をろ過にて取り出し、乾燥した後、メタノールを溶媒として固形分濃度10質量%になる様に溶解した。その後、MAA-BA共重合体1の溶解に用いたメタノールと同じ質量の蒸留水に対して、得られたMAA-BA共重合体1/メタノール溶液を滴下し、MAA-BA共重合体1からなる樹脂粒子の分散液を得た。その後、この分散液を60℃になるように加温しながら沸騰しない様に減圧処理して、メタノールを除去し、固形分濃度が10質量%のメタクリル酸-アクリル酸n-ブチル-メタクリル酸トリブロック共重合体1(MAA-BA-MAAトリブロック共重合体1)からなる樹脂粒子1の水分散液を得た。なお、このMAA-BA-MAAトリブロック共重合体1は、熱可塑性エラストマーである。
(1)PVA(けん化度99.3モル%、重合度2400、エチレン変性量2.5モル%)100質量部、可塑剤としてグリセリン10質量部、界面活性剤としてポリオキシエチレンラウリルエーテル硫酸ナトリウム0.1質量部、及び上記樹脂粒子1(MAA-BA-MAAトリブロック共重合体1)を5質量部含む、PVAの含有率が10質量%である水溶液を作製し、これを製膜原液として用いた。この製膜原液を80℃の金属ロール上で乾燥し、得られたPVAフィルムを熱風乾燥機中で120℃の温度で10分間熱処理し、平均厚み30μmの原反フィルムを得た。原反フィルム中の樹脂粒子の平均粒径を測定したところ、30nmであった。また、原反フィルム中の樹脂粒子の含有量を測定したところ、4質量%であった。これらの結果を表1にまとめた。
PVA100質量部に対する上記樹脂粒子1の混合量を10質量部としたこと以外は実施例1と同様の方法で原反フィルム及び偏光フィルムを作製した。
得られた原反フィルムの平均厚み、原反フィルム中の樹脂粒子の平均粒径、原反フィルム中の樹脂粒子の含有量、偏光フィルムの平均厚み、偏光フィルム中の樹脂粒子の平均粒径、偏光フィルム中の樹脂粒子の含有量、偏光フィルムの裂け強度、及び偏光性能を測定又は評価した。それらの結果を表1に示した。
PVA100質量部に対する上記樹脂粒子1の混合量を20質量部としたこと以外は実施例1と同様の方法で原反フィルム及び偏光フィルムを作製した。
得られた原反フィルムの平均厚み、原反フィルム中の樹脂粒子の平均粒径、原反フィルム中の樹脂粒子の含有量、偏光フィルムの平均厚み、偏光フィルム中の樹脂粒子の平均粒径、偏光フィルム中の樹脂粒子の含有量、偏光フィルムの裂け強度、及び偏光性能を測定又は評価した。それらの結果を表1に示した。
製膜原液に加えた樹脂粒子1を上記樹脂粒子2(MAA-BA-MAAトリブロック共重合体2)に変更したこと以外は実施例1と同様の方法で原反フィルム及び偏光フィルムを作製した。
得られた原反フィルムの平均厚み、原反フィルム中の樹脂粒子の平均粒径、原反フィルム中の樹脂粒子の含有量、偏光フィルムの平均厚み、偏光フィルム中の樹脂粒子の平均粒径、偏光フィルム中の樹脂粒子の含有量、偏光フィルムの裂け強度、及び偏光性能を測定又は評価した。それらの結果を表1に示した。
製膜原液に加えた樹脂粒子1を上記樹脂粒子2に変更したこと以外は実施例3と同様の方法で原反フィルム及び偏光フィルムを作製した。
得られた原反フィルムの平均厚み、原反フィルム中の樹脂粒子の平均粒径、原反フィルム中の樹脂粒子の含有量、偏光フィルムの平均厚み、偏光フィルム中の樹脂粒子の平均粒径、偏光フィルム中の樹脂粒子の含有量、偏光フィルムの裂け強度、及び偏光性能を測定又は評価した。それらの結果を表1に示した。
製膜原液に加えた樹脂粒子1を大成ファインケミカルの「WAN-6000」(ウレタン樹脂からなる樹脂粒子)に変更したこと以外は実施例3と同様の方法で原反フィルム及び偏光フィルムを作製した。
得られた原反フィルムの平均厚み、原反フィルム中の樹脂粒子の平均粒径、原反フィルム中の樹脂粒子の含有量、偏光フィルムの平均厚み、偏光フィルム中の樹脂粒子の平均粒径、偏光フィルム中の樹脂粒子の含有量、偏光フィルムの裂け強度、及び偏光性能を測定又は評価した。それらの結果を表1に示した。
製膜原液に樹脂粒子1を加えなかったこと以外は実施例1と同様の方法で原反フィルム及び偏光フィルムを作製した。
得られた原反フィルムの平均厚み、偏光フィルムの平均厚み、偏光フィルムの裂け強度、及び偏光性能を測定又は評価した。それらの結果を表1に示した。
PVA100質量部に対する上記樹脂粒子1の混合量を40質量部としたこと以外は実施例1と同様の方法で原反フィルム及び偏光フィルムを作製した。
得られた原反フィルムの平均厚み、原反フィルム中の樹脂粒子の平均粒径、原反フィルム中の樹脂粒子の含有量、偏光フィルムの平均厚み、偏光フィルム中の樹脂粒子の平均粒径、偏光フィルム中の樹脂粒子の含有量、偏光フィルムの裂け強度、及び偏光性能を測定又は評価した。それらの結果を表1に示した。
製膜原液に加えた樹脂粒子1を星光PMC社の「PE―1304」(スチレンアクリル樹脂からなる樹脂粒子、メーカー公表平均粒径250nm)に変更したこと以外は実施例3と同様の方法で原反フィルムと偏光フィルムを作製しようとした。しかし、原反フィルムが白く濁ったため、偏光フィルムの作製や各種評価を中止した。
製膜原液に加えた樹脂粒子1を日産化学工業社の「スノーテックス ST-50」(シリカ粒子、メーカー公表平均粒径20~25nm)に変更したこと以外は実施例3と同様の方法で原反フィルムと偏光フィルムを作製しようとした。しかし、原反フィルムが白く濁ったため、偏光フィルムの作製や各種評価を中止した。
樹脂粒子1に替えて、和光純薬社のポリアクリル酸(重合度2000)を製膜原液に加えたこと以外は実施例1と同様の方法で原反フィルムと偏光フィルムを作製した。
得られた原反フィルムの平均厚み、原反フィルム中の樹脂粒子の平均粒径、原反フィルム中の樹脂粒子の含有量、偏光フィルムの平均厚み、偏光フィルム中の樹脂粒子の平均粒径、偏光フィルム中の樹脂粒子の含有量、偏光フィルムの裂け強度、及び偏光性能を測定又は評価した。それらの結果を表1に示した。ポリアクリル酸は、フィルム中で粒子として存在せず、PVAと相溶していた。
洗浄処理浴にアスコルビン酸ナトリウム0.0316質量%を加えたこと以外は比較例1と同様の方法で原反フィルムと偏光フィルムを作製した。
得られた原反フィルムの平均厚み、偏光フィルムの平均厚み、偏光フィルムの裂け強度、及び偏光性能を測定又は評価した。それらの結果を表1に示した。
一軸延伸処理浴において全体で延伸倍率(総延伸倍率)が4倍になるように延伸したこと以外は比較例1と同様の方法で原反フィルムと偏光フィルムを作製した。
得られた原反フィルムの平均厚み、偏光フィルムの平均厚み、偏光フィルムの裂け強度、及び偏光性能を測定又は評価した。それらの結果を表1に示した。
原反フィルムの平均厚みを40μmにしたこと以外は比較例1と同様の方法で原反フィルムと偏光フィルムを作製した。
得られた原反フィルムの平均厚み、偏光フィルムの平均厚み、偏光フィルムの裂け強度、及び偏光性能を測定又は評価した。それらの結果を表1に示した。
原反フィルムの平均厚みを60μmにしたこと以外は比較例1と同様の方法で原反フィルムと偏光フィルムを作製した。
得られた原反フィルムの平均厚み、偏光フィルムの平均厚み、偏光フィルムの裂け強度、及び偏光性能を測定又は評価した。それらの結果を表1に示した。
A:偏光フィルムの平均厚み20μm以下、裂け強度2N以上、かつ偏光度99.994%超
B:偏光フィルムの平均厚み20μm以下、裂け強度2N以上、かつ偏光度99.990%超99.994%以下
C:上記A及びB以外
Claims (4)
- 平均厚みが45μm以下であり、
主成分であるビニルアルコール系重合体と、平均粒径が25nm以上150nm以下の樹脂粒子とを含有し、
上記樹脂粒子の含有量が1質量%以上25質量%以下である延伸光学フィルム製造用の原反フィルム。 - 上記樹脂粒子が重合体を含有し、
上記重合体が、ヒドロキシ基を含む基を有する構造単位を備える請求項1に記載の原反フィルム。 - 請求項1又は請求項2に記載の原反フィルムを延伸する工程
を備える延伸光学フィルムの製造方法。 - 平均厚みが20μm以下であり、
主成分であるビニルアルコール系重合体と、平均粒径が25nm以上150nm以下の樹脂粒子とを含有し、
上記樹脂粒子の含有量が1質量%以上25質量%以下である延伸光学フィルム。
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