WO2011030684A1 - 光学フィルムの製造方法、光学フィルム、偏光板及び液晶表示装置 - Google Patents
光学フィルムの製造方法、光学フィルム、偏光板及び液晶表示装置 Download PDFInfo
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- WO2011030684A1 WO2011030684A1 PCT/JP2010/064689 JP2010064689W WO2011030684A1 WO 2011030684 A1 WO2011030684 A1 WO 2011030684A1 JP 2010064689 W JP2010064689 W JP 2010064689W WO 2011030684 A1 WO2011030684 A1 WO 2011030684A1
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
- B29D11/00—Producing optical elements, e.g. lenses or prisms
- B29D11/0074—Production of other optical elements not provided for in B29D11/00009- B29D11/0073
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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
- B29C59/00—Surface shaping of articles, e.g. embossing; Apparatus therefor
- B29C59/02—Surface shaping of articles, e.g. embossing; Apparatus therefor by mechanical means, e.g. pressing
- B29C59/04—Surface shaping of articles, e.g. embossing; Apparatus therefor by mechanical means, e.g. pressing using rollers or endless belts
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- the present invention relates to an optical film manufacturing method, an optical film, a polarizing plate, and a liquid crystal display device.
- an optical film for a display device a wide film having a size of 1000 mm or more and further 1400 mm or more is required due to the recent enlargement of the screen.
- the width of the optical film becomes wider, the film thickness becomes thinner, and when the production speed is increased, the roll is easily tightened or the film is easily deformed at the stage of winding the optical film.
- the non-uniformity of roll tightening and deformation of the film are recognized as a black band (hereinafter referred to as a black band) on the circumference of the roll.
- the roll tightening also makes it easy to cause close contact between the film surfaces (hereinafter referred to as blocking).
- the optical film unrolled from the roll in which the black band or blocking occurs causes wrinkles, scratches, etc., and cannot be applied to a display device, resulting in a decrease in yield.
- Patent Document 1 an embossing roll having a tooth tip shape of 90 to 130 ° is used to press against the surface of the film end portion, and the film thickness of the film end portion is deformed to perform a knurling process.
- a method has been proposed.
- FIG. 9A is a schematic view showing a state in which knurling is performed on an end portion of the optical film 101 by an embossing roll 102 and a backup roll 103 having a flat surface.
- FIG. 9B shows the teeth 104 of the embossing roll 102, which is a cross-sectional shape of a quadrangular pyramid tooth having a flat tip.
- FIG.9 (c) is the figure which expanded the cross section of the film after a knurling process.
- the film material pushed away by the teeth 104 of the embossing roll 102 is pushed to the outer periphery of the teeth 104, and the surface of the film 101 has concave portions 107 and 107.
- a convex portion (protruding portion) 106 is formed around the concave portion 107.
- the convex portion (bump portion) 106 is caused by the tightness of the film or the weight of the film, as shown in FIG. It becomes unable to withstand that load and it collapses, causing problems such as black bands and blocking. From this, the present inventor has focused on the shape of the concavo-convex portion that is not easily crushed and has reached the present invention.
- an object of the present invention is to provide an optical film free from wrinkles and scratches, and a method for producing the same, without causing foreign matter failure on the film surface or occurrence of black bands or blocking in a roll shape, and the optical film. It is providing the polarizing plate using this, and the liquid crystal display device using this polarizing plate.
- the present invention has the following features.
- the step of imparting the knurling includes: When the projection is pressed against the surface of the film, the height of the projection formed by the film member pushed away by the projection is limited by the flat portion constituting the base of the projection, and the projection The manufacturing method of the optical film characterized by making the height of a part into predetermined height.
- a polarizing plate wherein the optical film according to any one of 1 to 4 is disposed on a surface of a polarizer.
- a liquid crystal display device comprising the polarizing plate described in 6 above.
- the optical film even if the optical film is wide and thin, it is possible to provide an optical film that is free from black bands and blocking and has no wrinkles or scratches, and a method for producing the same.
- a high-quality polarizing plate using the optical film and a liquid crystal display device using the polarizing plate can be provided.
- FIG. 1 It is a schematic diagram which shows the optical film of this invention. Sectional drawing which cut
- a knurling process for forming a plurality of concave and convex portions having a concave portion and a convex portion (bump portion) formed around the concave portion at both side end portions in the width direction of the long film is performed.
- the protrusions of the pair of protrusions and recesses are cut by a plane parallel to the surface of the film at a half of the average height from the surface of the film of the protrusions, the sectional area S per protrusion Is 2500 to 10000 ⁇ m 2 and the average width W of the convex portions is 3 to 20 ⁇ m.
- Fig.1 (a) shows the top view of the optical film 1 of this invention, and has the knurling process part 12 which consists of several unevenness
- corrugations convex part 13, recessed part 14 in the side edge part of the width direction of an optical film.
- FIG. 1 (b) shows a cross-sectional view in which a pair of irregularities (13, 14) among a plurality of irregularities of the formed knurling portion 12 is cut in the thickness direction of the optical film 1.
- FIG. 2 shows a cross-sectional view of the convex portion 13 of FIG. 1 cut along a plane parallel to the surface of the optical film 1 (cross section AA in FIG. 1) at half the height H of the convex portion 13. .
- the average width W of the convex portions in the cross section is in the range of 3 to 20 ⁇ m and the cross sectional area S is in the range of 2500 to 10000 ⁇ m 2 , the winding speed can be increased, Even if the length is increased, it is possible to suppress the occurrence of a black band or blocking in a rolled state, and an optical film with few wrinkles and scratches can be obtained.
- the average width W is determined by measuring the widths W1, W2, W3, and W4 at the center of each side of the cross-sectional shape of the convex portion 13 in FIG. If the cross-sectional shape is not a quadrangle as shown in FIG. 2, four points are measured at almost equal intervals, and the average value is calculated.
- the ratio S / H between the cross-sectional area S ( ⁇ m 2 ) and the average height H ( ⁇ m) from the surface of the convex film is preferably 100 to 3000.
- the ratio S / Y between the cross-sectional area S ⁇ m 2 and the widest width Y ⁇ m (see FIG. 2) of the recess is preferably 10 to 300.
- S / Y is a portion of the widest distance in the width of the concave portion as shown in the sectional view of FIG.
- a pair of irregularities is formed at 10 to 300 pieces / cm 2 at the side end of the knurled film.
- a plurality of protrusions are pressed against the surface of the side end portion of the film to form a plurality of pairs of protrusions and recesses.
- the height of the projection formed by the film member pushed away by the projection is limited by the flat portion constituting the base of the projection, and the height of the projection is a predetermined height.
- FIG. 3A shows an embossing roll 61 having a plurality of protrusions 20 on a cylindrical flat surface 21 (also referred to as a flat part), and the embossing roll 61 and the optical film 1 sandwiched therebetween. It is the figure which showed typically the knurling process which knurles the both ends of the optical film 1 with the backup roll 62.
- FIG. 3A shows an embossing roll 61 having a plurality of protrusions 20 on a cylindrical flat surface 21 (also referred to as a flat part), and the embossing roll 61 and the optical film 1 sandwiched therebetween. It is the figure which showed typically the knurling process which knurles the both ends of the optical film 1 with the backup roll 62.
- FIG. 3 (b) is an enlarged view of a forming part for forming irregularities on the optical film by the protruding part 20.
- the projecting portion 20 has a quadrangular pyramid shape with the tip portion 20a having a flat surface.
- the protrusions 20 are pressed against the surface of the film 1 to form the protrusions 13.
- the top portion 13a of the convex portion 13 is pressed by the flat portion 21 that constitutes the base portion of the protruding portion 20, and the height H0 is limited.
- the film material pushed away by the protruding portion spreads in the width direction when reaching a certain height. Therefore, the height of the convex portion 13 can be stably formed, and the width value can be stably formed by limiting the height.
- the height and width of the convex portion to be formed tend to vary.
- the width W01 of the protruding portion that protrudes along the side surface of the protruding portion 31 is narrowed, or as shown in FIG. 5, the width of the top portion 13a is narrow and the width of the bottom portion is wide. It becomes a shape. Therefore, it is preferable to limit the height of the convex portion as shown in FIG.
- the predetermined range is within the scope of the present invention.
- the convex part which has a width
- the convex portion and the concave portion having a predetermined shape are prevented from being crushed by the load applied to the top portion 13a. Since it can be formed, blocking and black band phenomenon in a roll state in which the film is wound can be suppressed. As a result, wrinkles and scratches generated on the film can be reduced.
- a quadrangular pyramid having a flat surface on the top 13a is used as an example, but it may be a triangular pyramid or a cone, and the top may be an arc. What is necessary is just the structure which controls the extruded film material with the flat part which comprises the base of a projection part, when a projection part is pressed on a film. With such a configuration, it is possible to stably form a convex portion having a predetermined height and width.
- the method for producing an optical film of the present invention relates to knurling of an optical film produced by a solution casting film forming method or a melt casting film forming method. First, an optical film produced by a solution casting film forming method is used. A manufacturing method will be described.
- various resins can be used as the film material, and among them, cellulose ester is preferable.
- Cellulose ester is a cellulose ester in which a hydroxyl group derived from cellulose is substituted with an acyl group or the like.
- examples thereof include cellulose acylates such as cellulose acetate, cellulose triacetate, cellulose acetate propionate, cellulose acetate butyrate and cellulose acetate propionate butyrate, and cellulose acetate having an aliphatic polyester graft side chain.
- cellulose acetate, cellulose acetate propionate, and cellulose acetate having an aliphatic polyester graft side chain are preferable.
- Other substituents may be included as long as the effects of the present invention are not impaired.
- the substitution degree of acetyl group is preferably 2.0 or more and 3.0 or less. By setting the degree of substitution within this range, good moldability can be obtained, and desired in-plane retardation (Ro) and thickness direction retardation (Rt) can be obtained. If the substitution degree of the acetyl group is lower than this range, the heat resistance as a retardation film, particularly the dimensional stability under wet heat may be inferior, and if the substitution degree is too large, the necessary retardation characteristics will not be exhibited. There is a case.
- the cellulose used as a raw material of the cellulose ester used in the present invention is not particularly limited, and examples thereof include cotton linter, wood pulp, and kenaf. Moreover, the cellulose ester obtained from them can be mixed and used in arbitrary ratios, respectively.
- the number average molecular weight of the cellulose ester is preferably in the range of 60,000 to 300,000, since the mechanical strength of the resulting film is strong. Furthermore, 70,000 to 200,000 are preferable.
- the cellulose ester used in the present invention preferably has an Mw / Mn ratio of 1.4 to 3.0, more preferably 1.4 to 2.3.
- the average molecular weight and molecular weight distribution of the cellulose ester can be measured using high performance liquid chromatography, the number average molecular weight (Mn) and the mass average molecular weight (Mw) can be calculated using this, and the ratio can be calculated.
- the measurement conditions are as follows.
- the total acyl group substitution degree of the cellulose ester is 2.3 to 2.9, and 2.6 to 2.9 is preferably used.
- the total degree of acyl group substitution can be measured according to ASTM-D817-96.
- various additives can be added to the cellulose ester.
- reducing the thickness direction retardation (Rt) of the optical film is important in terms of expanding the viewing angle of the liquid crystal display device operating in the IPS mode.
- a retardation reducing additive is used. The following may be mentioned as:
- an additive for reducing the retardation of the cellulose ester is an additive that disturbs the orientation of the cellulose ester and is difficult to orient itself and / or has a small polarizability anisotropy. It is a compound that effectively reduces it. Therefore, as an additive for disturbing the orientation of the cellulose ester, an aliphatic compound is preferable to an aromatic compound.
- specific retardation reducing agents include, for example, polyesters represented by the following general formula (1) or (2).
- B 1 represents a monocarboxylic acid component
- B 2 represents a monoalcohol component
- G represents a divalent alcohol component
- A represents a dibasic acid component, and these are synthesized.
- B 1 , B 2 , G, and A are all characterized by not containing an aromatic ring.
- m and n represent the number of repetitions.
- Monocarboxylic acid component represented by B may be known aliphatic monocarboxylic acid, alicyclic monocarboxylic acid.
- Examples of preferred monocarboxylic acids include the following, but the present invention is not limited thereto.
- aliphatic monocarboxylic acid a straight-chain or side-chain fatty acid having 1 to 32 carbon atoms can be preferably used. More preferably, it has 1-20 carbon atoms, and particularly preferably has 1-12 carbon atoms.
- acetic acid is contained, the compatibility with the cellulose ester is increased, and it is also preferable to use a mixture of acetic acid and another monocarboxylic acid.
- Preferred monocarboxylic acids include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, 2-ethyl-hexanecarboxylic acid, undecylic acid, lauric acid, tridecylic acid , Saturated fatty acids such as myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, heptacosanoic acid, montanic acid, melicic acid, and laccelic acid, undecinic acid, Examples thereof include unsaturated fatty acids such as oleic acid, sorbic acid, linoleic acid, linolenic acid and arachidonic acid.
- the monoalcohol component represented by B 2 may be a known alcohol.
- an aliphatic saturated alcohol or aliphatic unsaturated alcohol having a straight chain or a side chain having 1 to 32 carbon atoms can be preferably used. More preferably, it has 1-20 carbon atoms, and particularly preferably has 1-12 carbon atoms.
- Examples of the divalent alcohol component represented by G include the following, but the present invention is not limited thereto.
- ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 1,5-pentanediol, 1,6- Examples include hexanediol, 1,5-pentylene glycol, diethylene glycol, triethylene glycol, and tetraethylene glycol.
- ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1 , 2-butylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 1,6-hexanediol, diethylene glycol and triethylene glycol are preferred, and 1,3-propylene glycol and 1,4-butylene glycol are also preferred.
- Lumpur, 1,6-hexanediol, diethylene glycol is preferably used.
- the dibasic acid (dicarboxylic acid) component represented by A is preferably an aliphatic dibasic acid or an alicyclic dibasic acid.
- the aliphatic dibasic acid include malonic acid, succinic acid, glutaric acid, and adipic acid. , Pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, etc.
- aliphatic carboxylic acid those having 4 to 12 carbon atoms, at least one selected from these are used. To do. That is, two or more dibasic acids may be used in combination.
- the number of repetitions m and n in the general formula (1) or (2) is preferably 1 or more and 170 or less.
- the mass average molecular weight of the polyester is preferably 20000 or less, and more preferably 10,000 or less.
- polyesters having a weight average molecular weight of 500 to 10,000 have good compatibility with cellulose esters, and neither evaporation nor volatilization occurs during film formation.
- Polyester polycondensation is performed by conventional methods. For example, a direct reaction of the dibasic acid and glycol, a hot melt condensation method by the polyesterification reaction or transesterification reaction of the dibasic acid or alkyl esters thereof, for example, a methyl ester of dibasic acid and glycols, or Although it can be easily synthesized by any method of dehydrohalogenation reaction between acid chloride of these acids and glycol, polyesters having a mass average molecular weight not so large are preferably directly reacted. Polyester having a high distribution on the low molecular weight side has a very good compatibility with the cellulose ester, and after forming the film, a moisture permeability is small, and a cellulose ester film rich in transparency can be obtained.
- a direct reaction of the dibasic acid and glycol a hot melt condensation method by the polyesterification reaction or transesterification reaction of the dibasic acid or alkyl esters thereof, for example, a methyl ester of dibasic acid and glycol
- the molecular weight adjustment method is not particularly limited, and a conventional method can be used.
- the amount of these monovalent compounds can be controlled by a method of blocking the molecular ends with a monovalent acid or monovalent alcohol.
- a monovalent acid is preferable from the viewpoint of polymer stability.
- acetic acid, propionic acid, butyric acid, etc. can be mentioned, but during the polycondensation reaction, it is not distilled out of the system, but is stopped and such monovalent acid is removed from the reaction system. The one that is easy to accumulate is selected. These may be used in combination.
- the mass average molecular weight can also be adjusted by measuring the timing at which the reaction is stopped by the amount of water distilled off during the reaction. In addition, it can be adjusted by biasing the number of moles of glycol or dibasic acid to be charged, or can be adjusted by controlling the reaction temperature.
- the polyester represented by the general formula (1) or (2) is preferably contained in an amount of 1 to 40% by mass with respect to the cellulose ester.
- the content is preferably 5 to 15% by mass.
- examples of the retardation reducing additive further include the following.
- the dope used for the production of the optical film of the present invention mainly contains a cellulose ester, a polymer as a retardation reducing additive (a polymer obtained by polymerizing an ethylenically unsaturated monomer, an acrylic polymer), and an organic solvent. To do.
- a polymerization method in order to synthesize a polymer as a retardation-reducing additive, it is difficult to control the molecular weight in normal polymerization, and it is desirable to use a method that can align the molecular weight as much as possible without increasing the molecular weight.
- a polymerization method include a method using a peroxide polymerization initiator such as cumene peroxide and t-butyl hydroperoxide, a method using a polymerization initiator in a larger amount than usual polymerization, and a mercapto compound in addition to the polymerization initiator.
- a method using a chain transfer agent such as carbon tetrachloride a method using a polymerization terminator such as benzoquinone and dinitrobenzene in addition to the polymerization initiator, and JP-A No. 2000-128911 or JP-A No. 2000-344823.
- Examples include a compound having a single thiol group and a secondary hydroxyl group as described in the publication, or a bulk polymerization method using a polymerization catalyst in which the compound and an organometallic compound are used in combination. In particular, the method described in the publication is preferred.
- monomers as monomer units constituting a polymer as a useful retardation reducing additive are listed below, but are not limited thereto.
- an ethylenically unsaturated monomer unit constituting a polymer as a retardation reducing additive obtained by polymerizing an ethylenically unsaturated monomer first, as a vinyl ester, for example, vinyl acetate, vinyl propionate, vinyl butyrate, valeric acid Vinyl, vinyl pivalate, vinyl caproate, vinyl caprate, vinyl laurate, vinyl myristate, vinyl palmitate, vinyl stearate, vinyl cyclohexanecarboxylate, vinyl octylate, vinyl methacrylate, vinyl crotrate, vinyl sorbate , Vinyl benzoate, vinyl cinnamate and the like.
- a vinyl ester for example, vinyl acetate, vinyl propionate, vinyl butyrate, valeric acid Vinyl, vinyl pivalate, vinyl caproate, vinyl caprate, vinyl laurate, vinyl myristate, vinyl palmitate, vinyl stearate, vinyl cyclohexanecarboxylate, vinyl octylate
- acrylate esters for example, methyl acrylate, ethyl acrylate, propyl acrylate (i-, n-), butyl acrylate (n-, i-, s-, t-), pentyl acrylate ( n-, i-, s-), hexyl acrylate (n-, i-), heptyl acrylate (n-, i-), octyl acrylate (n-, i-), nonyl acrylate (n-, i-), myristyl acrylate (n-, i-), cyclohexyl acrylate, acrylic acid (2-ethylhexyl), benzyl acrylate, phenethyl acrylate, acrylic acid ( ⁇ -caprolactone), acrylic acid (2-hydroxyethyl) ), Acrylic acid (2-hydroxypropyl), acrylic acid (3-hydroxypropyl), acrylic acid (4-hydroxybutyl), acrylic acid
- examples of the unsaturated acid include acrylic acid, methacrylic acid, maleic anhydride, crotonic acid, itaconic acid and the like.
- the polymer composed of the above monomers may be a copolymer or a homopolymer, and is preferably a vinyl ester homopolymer, a vinyl ester copolymer, or a copolymer of vinyl ester and acrylic acid or methacrylic acid ester.
- an acrylic polymer refers to a homopolymer or copolymer of acrylic acid or methacrylic acid alkyl ester having no monomer unit having an aromatic ring or a cyclohexyl group.
- acrylate monomer having no aromatic ring and cyclohexyl group examples include, for example, methyl acrylate, ethyl acrylate, propyl acrylate (i-, n-), butyl acrylate (n-, i-, s-, t-), pentyl acrylate (n-, i-, s-), hexyl acrylate (n-, i-), heptyl acrylate (n-, i-), octyl acrylate (n-, i-) ,
- the acrylic polymer is a homopolymer or copolymer of the above-mentioned monomers, but it is preferable that the acrylic acid methyl ester monomer unit has 30% by mass or more, and the methacrylic acid methyl ester monomer unit has 40% by mass or more. It is preferable. In particular, a homopolymer of methyl acrylate or methyl methacrylate is preferred.
- Polymers obtained by polymerizing the above ethylenically unsaturated monomers and acrylic polymers are both highly compatible with cellulose ester, excellent in productivity without evaporation and volatilization, and retainability as a protective film for polarizing plates
- the moisture permeability is small, and the dimensional stability is excellent.
- an acrylic acid or methacrylic acid ester monomer having a hydroxyl group is not a homopolymer but a constituent unit of a copolymer.
- the acrylic acid or methacrylic acid ester monomer unit having a hydroxyl group is preferably contained in the acrylic polymer in an amount of 2 to 20% by mass.
- the dope composition preferably contains a cellulose ester and an acrylic polymer having a mass average molecular weight of 500 or more and 3000 or less as a retardation reducing additive.
- the dope composition preferably contains a cellulose ester and an acrylic polymer having a mass average molecular weight of 5,000 to 30,000 as a retardation reducing additive.
- the weight average molecular weight of the polymer as the retardation reducing additive is 500 or more and 3000 or less, or if the polymer has a weight average molecular weight of 5000 or more and 30000 or less, the compatibility with the cellulose ester is good, There is no evaporation or volatilization in the film. Moreover, the transparency of the optical film after film formation is excellent, and the water vapor transmission rate is also extremely low, which shows excellent performance as a protective film for polarizing plates.
- a polymer having a hydroxyl group in the side chain can also be preferably used as a retardation reducing additive.
- the monomer unit having a hydroxyl group is the same as the monomer described above, but acrylic acid or methacrylic acid ester is preferable.
- Examples include those substituted with methacrylic acid, preferably 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate.
- the acrylic acid ester or methacrylic acid ester monomer unit having a hydroxyl group in the polymer is preferably contained in the polymer in an amount of 2 to 20% by mass, more preferably 2 to 10% by mass.
- a polymer containing 2 to 20% by mass of the above-mentioned monomer unit having a hydroxyl group has excellent compatibility with cellulose ester, retention, dimensional stability, and low moisture permeability. It is particularly excellent in adhesion with a polarizer as a protective film for a polarizing plate, and has an effect of improving the durability of the polarizing plate.
- At least one terminal of the main chain of the polymer has a hydroxyl group.
- the method of having a hydroxyl group at the end of the main chain is not particularly limited as long as it has a hydroxyl group at the end of the main chain, but radical polymerization having a hydroxyl group such as azobis (2-hydroxyethylbutyrate) is possible.
- the polymer produced by the method related to the description in this publication is commercially available as Act Flow Series manufactured by Soken Chemical Co., Ltd., and can be preferably used.
- the polymer having a hydroxyl group at the terminal and / or the polymer having a hydroxyl group in the side chain has an effect of significantly improving the compatibility and transparency of the polymer with respect to the cellulose ester.
- useful retardation-reducing additives in the present invention include, for example, ester compounds of diglycerin polyhydric alcohols and fatty acids described in JP-A-2000-63560, and JP-A-2001-247717.
- Hexose sugar alcohol ester or ether compound Japanese Patent Application Laid-Open No. 2004-315613 phosphate trialiphatic alcohol ester compound, Japanese Patent Application Laid-Open No. 2005-41911 compound represented by general formula (1)
- Examples thereof include a phosphoric acid ester compound described in Japanese Patent Application Laid-Open No. 2004-315605, a styrene oligomer described in Japanese Patent Application Laid-Open No. 2005-105139, and a polymer of a styrene monomer described in Japanese Patent Application Laid-Open No. 2005-105140.
- the content of the retardation reducing additive described above is preferably 5 to 25% by mass with respect to the cellulose ester resin. If the content of the retardation-reducing additive is less than 5% by mass, the effect of reducing the retardation of the film is not exhibited, which is not preferable. On the other hand, when the content of the retardation reducing additive exceeds 25% by mass, the so-called bleed out occurs and the stability in the film decreases, which is not preferable.
- an organic solvent having good solubility with respect to the cellulose derivative is referred to as a good solvent, and has a main effect on dissolution.
- Organic) solvent or main (organic) solvent is referred to as a good solvent, and has a main effect on dissolution.
- Examples of good solvents include ketones such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, ethers such as tetrahydrofuran (THF), 1,4-dioxane, 1,3-dioxolane, 1,2-dimethoxyethane, formic acid Esters such as methyl, ethyl formate, methyl acetate, ethyl acetate, amyl acetate, ⁇ -butyrolactone, methyl cellosolve, dimethylimidazolinone, dimethylformamide, dimethylacetamide, acetonitrile, dimethylsulfoxide, sulfolane, nitroethane, methylene chloride And 1,3-dioxolane, THF, methyl ethyl ketone, acetone, methyl acetate and methylene chloride are preferable.
- ketones such as acetone, methyl eth
- the dope preferably contains 1 to 40% by mass of an alcohol having 1 to 4 carbon atoms in addition to the organic solvent.
- the solvent starts to evaporate and the alcohol ratio increases, so the web (name of the dope film after casting the cellulose derivative dope on the metal support) Is used as a gelling solvent that makes the web strong and makes it easy to peel off from the metal support, or when these ratios are small, cellulose derivatives of non-chlorine organic solvents There is also a role to promote the dissolution of.
- Examples of the alcohol having 1 to 4 carbon atoms include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, tert-butanol, and propylene glycol monomethyl ether.
- ethanol is preferred because it has excellent dope stability, has a relatively low boiling point, good drying properties, and no toxicity.
- These organic solvents alone are not soluble in cellulose derivatives and are called poor solvents.
- the most preferable solvent for dissolving a cellulose derivative, which is a preferable polymer compound satisfying such conditions, at a high concentration is a mixed solvent having a ratio of methylene chloride: ethyl alcohol of 95: 5 to 80:20.
- a mixed solvent of methyl acetate: ethyl alcohol 60:40 to 95: 5 is also preferably used.
- the film according to the present invention includes a plasticizer that imparts processability, flexibility, and moisture resistance to the film, fine particles that impart slipperiness to the film (matting agent), an ultraviolet absorber that imparts an ultraviolet absorbing function, and deterioration of the film. You may contain the antioxidant etc. which prevent.
- the plasticizer used in the present invention is not particularly limited. However, a cellulose derivative or a reactive metal compound capable of hydrolytic polycondensation can be used so as not to cause haze, bleed out or volatilize from the film. It preferably has a functional group capable of interacting with the condensate by hydrogen bonding or the like.
- Examples of such functional groups include hydroxyl groups, ether groups, carbonyl groups, ester groups, carboxylic acid residues, amino groups, imino groups, amide groups, imide groups, cyano groups, nitro groups, sulfonyl groups, sulfonic acid residues, Examples thereof include a phosphonyl group and a phosphonic acid residue, and a carbonyl group, an ester group and a phosphonyl group are preferred.
- plasticizers examples include phosphate ester plasticizers, phthalate ester plasticizers, trimellitic acid ester plasticizers, pyromellitic acid plasticizers, polyhydric alcohol ester plasticizers, glycolate plasticizers. Agents, citric acid ester plasticizers, fatty acid ester plasticizers, carboxylic acid ester plasticizers, polyester plasticizers, etc. can be preferably used, but polyhydric alcohol ester plasticizers, glycolate plasticizers are particularly preferred. And non-phosphate ester plasticizers such as polycarboxylic acid ester plasticizers.
- the polyhydric alcohol ester is composed of an ester of a dihydric or higher aliphatic polyhydric alcohol and a monocarboxylic acid, and preferably has an aromatic ring or a cycloalkyl ring in the molecule.
- the polyhydric alcohol used in the present invention is represented by the following general formula (3).
- R 1- (OH) n (However, R 1 represents an n-valent organic group, and n represents a positive integer of 2 or more.)
- R 1 represents an n-valent organic group, and n represents a positive integer of 2 or more.
- preferred polyhydric alcohols include the following, but the present invention is not limited to these.
- Examples of preferred polyhydric alcohols include adonitol, arabitol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, 1, 2-butanediol, 1,3-butanediol, 1,4-butanediol, dibutylene glycol, 1,2,4-butanetriol, 1,5-pentanediol, 1,6-hexanediol, hexanetriol, gallium
- Examples include lactitol, mannitol, 3-methylpentane-1,3,5-triol, pinacol, sorbitol, trimethylolpropane, trimethylolethane, and xylitol.
- the monocarboxylic acid used in the polyhydric alcohol ester of the present invention is not particularly limited, and known aliphatic monocarboxylic acid, alicyclic monocarboxylic acid, aromatic monocarboxylic acid and the like can be used. Use of an alicyclic monocarboxylic acid or aromatic monocarboxylic acid is preferred in terms of improving moisture permeability and retention.
- Examples of preferred monocarboxylic acids include the following, but the present invention is not limited thereto.
- aliphatic monocarboxylic acid a fatty acid having a straight chain or a side chain having 1 to 32 carbon atoms can be preferably used.
- the number of carbon atoms is more preferably 1-20, and particularly preferably 1-10.
- acetic acid is contained, the compatibility with the cellulose derivative is increased, and it is also preferable to use a mixture of acetic acid and another monocarboxylic acid.
- Examples of preferred aliphatic monocarboxylic acids include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, 2-ethyl-hexanecarboxylic acid, undecylic acid, lauric acid, Tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, heptacosanoic acid, montanic acid, mellicic acid, laccellic acid, etc., undecylen Examples thereof include unsaturated fatty acids such as acid, oleic acid, sorbic acid, linoleic acid, linolenic acid, and arachidonic acid.
- Examples of preferable alicyclic monocarboxylic acids include cyclopentane carboxylic acid, cyclohexane carboxylic acid, cyclooctane carboxylic acid, and derivatives thereof.
- aromatic monocarboxylic acids examples include those in which an alkyl group is introduced into the benzene ring of benzoic acid such as benzoic acid and toluic acid, and two or more benzene rings such as biphenylcarboxylic acid, naphthalenecarboxylic acid, and tetralincarboxylic acid. Examples thereof include aromatic monocarboxylic acids and derivatives thereof, and benzoic acid is particularly preferable.
- the molecular weight of the polyhydric alcohol ester is not particularly limited, but is preferably 300 to 1500, and more preferably 350 to 750. A higher molecular weight is preferred because it is less likely to volatilize, and a smaller one is preferred in terms of moisture permeability and compatibility with cellulose derivatives.
- the carboxylic acid used in the polyhydric alcohol ester may be one kind or a mixture of two or more kinds. Moreover, all the OH groups in the polyhydric alcohol may be esterified, or a part of the OH groups may be left as they are.
- the glycolate plasticizer is not particularly limited, but a glycolate plasticizer having an aromatic ring or a cycloalkyl ring in the molecule can be preferably used.
- a glycolate plasticizer having an aromatic ring or a cycloalkyl ring in the molecule can be preferably used.
- preferred glycolate plasticizers for example, butyl phthalyl butyl glycolate, ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate and the like can be used.
- phosphate plasticizers triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, diphenylbiphenyl phosphate, trioctyl phosphate, tributyl phosphate, etc.
- phthalate ester plasticizers diethyl phthalate, dimethoxy Ethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, dicyclohexyl phthalate, and the like can be used, but in the present invention, it is preferable that substantially no phosphate ester plasticizer is contained.
- substantially does not contain means that the content of the phosphoric ester plasticizer is less than 1% by mass, preferably 0.1% by mass, and particularly preferably not added.
- plasticizers can be used alone or in combination of two or more.
- the amount of plasticizer used is preferably 1 to 20% by mass. It is more preferably 6 to 16% by mass, particularly preferably 8 to 13% by mass. If the amount of the plasticizer used is less than 1% by mass relative to the cellulose derivative, the effect of reducing the moisture permeability of the film is small, so this is not preferred. If it exceeds 20% by mass, the plasticizer bleeds out from the film, and the film Since the physical properties of the material deteriorate, it is not preferable.
- fine particles such as a matting agent
- examples of the fine particles include fine particles of an inorganic compound or fine particles of an organic compound.
- inorganic compound fine particles include fine particles of silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, tin oxide, and the like. Of these, fine particles of a compound containing a silicon atom are preferred, and fine silicon dioxide particles are particularly preferred.
- silicon dioxide fine particles include Aerosil 200, 200V, 300, R972, R972V, R974, R202, R812, R805, OX50, and TT600 manufactured by Aerosil Co., Ltd.
- organic compound fine particles include fine particles of acrylic resin, silicone resin, fluorine compound resin, urethane resin, and the like.
- the primary particle size of the fine particles is not particularly limited, but the average particle size in the film is preferably about 0.05 to 5.0 ⁇ m. More preferably, it is 0.1 to 1.0 ⁇ m.
- the average particle diameter of the fine particles refers to the average value of the lengths of the particles in the major axis direction when the cellulose ester film is observed with an electron microscope or an optical microscope. As long as the particles are observed in the film, they may be primary particles or secondary particles in which the primary particles are aggregated, but most of the particles that are usually observed are secondary particles.
- the primary particle size, the particle size after being dispersed in a solvent, and the particle size added to the film often change, and what is important is that the fine particles are finally combined with the cellulose ester in the film to aggregate. And controlling the particle size formed.
- the average particle size of the fine particles exceeds 5 ⁇ m, haze deterioration or the like may be observed, or it may cause a failure in a wound state as a foreign matter. Moreover, when the average particle diameter of fine particles is less than 0.05 ⁇ m, it becomes difficult to impart slipperiness to the film.
- the above fine particles are used by adding 0.04 to 0.5 mass% with respect to the cellulose ester. Preferably, 0.05 to 0.3% by mass, more preferably 0.05 to 0.25% by mass is added.
- the amount of fine particles added is 0.04% by mass or less, the film surface roughness becomes too smooth, and blocking occurs due to an increase in the friction coefficient. If the amount of fine particles added exceeds 0.5% by mass, the coefficient of friction on the film surface will be too low, causing winding misalignment during winding, and the transparency of the film will be low and haze will be high.
- the above range is essential because it has no value as a film.
- the high-pressure dispersion apparatus used in the present invention is an apparatus that creates special conditions such as high shear and high pressure by passing a composition in which fine particles and a solvent are mixed at high speed through a narrow tube.
- the maximum pressure condition inside the apparatus is preferably 980 N / cm 2 or more in a thin tube having a tube diameter of 1 to 2000 ⁇ m by processing with a high-pressure dispersion apparatus. More preferably, the maximum pressure condition inside the apparatus is 1960 N / cm 2 or more. Further, at that time, those having a maximum reaching speed of 100 m / sec or more and those having a heat transfer speed of 420 kJ / h or more are preferable.
- Examples of the high-pressure dispersing device as described above include an ultra-high pressure homogenizer (trade name: Microfluidizer) manufactured by Microfluidics Corporation or a nanomizer manufactured by Nanomizer, and other examples include Manton Gorin type high-pressure dispersing devices such as Izumi Food Machinery. Examples thereof include a homogenizer.
- the fine particles are dispersed in a solvent containing 25 to 100% by mass of a lower alcohol, and then mixed with a dope in which a cellulose ester (cellulose derivative) is dissolved in a solvent, and the mixed solution is placed on a metal support.
- a cellulose ester film is obtained which is cast and dried to form a film.
- the content ratio of the lower alcohol is preferably 50 to 100% by mass, and more preferably 75 to 100% by mass.
- examples of lower alcohols preferably include methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol and the like.
- the solvent other than the lower alcohol is not particularly limited, but it is preferable to use a solvent used in film formation of cellulose ester.
- Fine particles are dispersed in a solvent at a concentration of 1 to 30% by mass. Dispersing at a concentration higher than this is not preferable because the viscosity increases rapidly.
- the concentration of the fine particles in the dispersion is preferably 5 to 25% by mass, more preferably 10 to 20% by mass.
- the ultraviolet absorbing function of the film is preferably imparted to various optical films such as a polarizing plate protective film, a retardation film, and an optical compensation film from the viewpoint of preventing deterioration of the liquid crystal.
- a material that absorbs ultraviolet rays may be included in the cellulose derivative, and a layer having an ultraviolet absorbing function may be provided on a film made of the cellulose derivative.
- Examples of the ultraviolet absorber that can be used in the present invention include oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex compounds, and the like. A benzotriazole-based compound with little coloring is preferable. Further, ultraviolet absorbers described in JP-A-10-182621 and JP-A-8-337574 and polymer ultraviolet absorbers described in JP-A-6-148430 are preferably used.
- ultraviolet absorber those having excellent absorption ability of ultraviolet rays having a wavelength of 370 nm or less from the viewpoint of preventing deterioration of a polarizer or liquid crystal and those having little absorption of visible light having a wavelength of 400 nm or more from the viewpoint of liquid crystal display properties. preferable.
- UV absorbers useful in the present invention include 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-tert- Butylphenyl) benzotriazole, 2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) ) -5-chlorobenzotriazole, 2- (2′-hydroxy-3 ′-(3 ′′, 4 ′′, 5 ′′, 6 ′′ -tetrahydrophthalimidomethyl) -5′-methylphenyl) benzotriazole, 2,2- Methylenebis (4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol), 2- (2'-hydro Cis-3'-tert-butyl-5'-methylphenyl) -5-chlorobenzo
- TINUVIN 109 As commercially available products of ultraviolet absorbers, TINUVIN 109, TINUVIN 171, and TINUVIN 326 (all manufactured by Ciba Japan Co., Ltd.) can be preferably used.
- the blending amount of these ultraviolet absorbers is preferably in the range of 0.01 to 10% by mass, more preferably 0.1 to 5% by mass with respect to the cellulose ester (cellulose derivative). If the amount of the ultraviolet absorber used is too small, the ultraviolet absorbing effect may be insufficient. If the amount of the ultraviolet absorber is too large, the transparency of the film may be deteriorated.
- the ultraviolet absorber is preferably one having high heat stability.
- the polymeric ultraviolet absorber (or ultraviolet absorbing polymer) described in JP-A Nos. 6-148430 and 2002-47357 is preferably used. be able to.
- the polymer ultraviolet absorber to be used is preferably used.
- the antioxidant is generally referred to as an anti-degradation agent, but is preferably contained in a cellulose ester film as an optical film. That is, when a liquid crystal image display device or the like is placed in a high humidity and high temperature state, the cellulose ester film as an optical film may be deteriorated.
- the antioxidant has a role of delaying or preventing the film from being decomposed by, for example, halogen in the residual solvent in the film or phosphoric acid of the phosphoric acid plasticizer, so that it is preferably contained in the film. .
- a hindered phenol compound is preferably used.
- 2,6-di-t-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di- -T-butyl-4-hydroxyphenyl) propionate] triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3 -(3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-t-butylanilino)- 1,3,5-triazine, 2,2-thio-diethylenebis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], oct Decyl-3- (3,5-di-t-butyl-4-hydroxyphenyl
- 2,6-di-t-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3 -(3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate] is preferred.
- hydrazine-based metal deactivators such as N, N′-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine and tris (2,4-di-t
- a phosphorus processing stabilizer such as -butylphenyl phosphite may be used in combination.
- the amount of these compounds to be added is preferably 1 ppm to 10,000 ppm, more preferably 10 to 1000 ppm by weight with respect to the cellulose derivative.
- the film can be produced by a solution casting method.
- FIG. 6 is a flow sheet schematically showing an apparatus for carrying out the method for producing an optical film of the present invention by a solution casting film forming method. Note that the implementation of the present invention is not limited to the process of FIG.
- thermoplastic resin solution (dope) is cast on a metal support 50 to form a casting film (web), and a part of the solvent
- the step of peeling the web 1 from the metal support 50 the step of stretching the peeled web 1 in the width direction by the tenter 53, and the step of drying the stretched web 1 with the drying device 54.
- the step of cutting both ends of the web 1 with slitters 56 and 57, and after cutting both ends the embossing roll 61 having protrusions on the surface and the web 1 are arranged at corresponding positions.
- the backup roll 62 includes a knurling process for knurling both ends of the web 1 and a winding process for winding the film (web) 1 after the knurling process.
- thermoplastic resin for example, a cellulose ester resin is dissolved in a mixed solvent of a good solvent and a poor solvent, and an additive such as the above plasticizer or ultraviolet absorber is added to the resin.
- a solution (dope) is prepared.
- the dope adjusted in the melting pot is fed to the casting die 51 through a conduit through, for example, a pressurized metering gear pump, and is transported infinitely as shown in FIG.
- the dope is cast from the casting die 51 at a casting position on the casting 50.
- Casting of the dope by the casting die 51 includes a doctor blade method in which the film thickness of the cast dope film (web) is adjusted with a blade, or a reverse roll coater method in which the film is adjusted with a reverse rotating roll.
- a pressure die that can adjust the slit shape of the die portion and can easily make the film thickness uniform is preferable. Examples of the pressure die include a coat hanger die and a T die, and any of them is preferably used.
- the casting die 51 is preferably a pressure die that can adjust the slit shape of the die portion and easily make the film thickness uniform.
- the solid content concentration of the cellulose ester solution (dope) is 20 to 30% by mass.
- the solid content concentration of the cellulose ester solution (dope) is less than 20% by mass, sufficient drying cannot be performed on the metal support 50, and a part of the dope film is separated from the metal support 50 at the time of peeling. It remains on top and leads to drum contamination, which is not preferable. If the solid content concentration exceeds 30%, the dope viscosity increases, filter clogging is accelerated in the dope adjustment process, and pressure increases when cast onto the metal support 50, making it impossible to extrude. It is not preferable.
- the belt metal support 50 is disposed between a pair of drums and an intermediate portion thereof, and an upper transition portion of the endless belt metal support 50; It consists of a plurality of rolls (not shown) each supporting the lower transition part from the back side.
- One or both of the drums at both ends of the metal support 50 are provided with a drive device that applies tension to the metal support 50, whereby the belt metal support 50 is tensioned and stretched. Used in the state.
- the peripheral speed of the metal support 50 is preferably 50 to 150 m / min.
- the belt temperature during film formation is a general temperature range of 0 ° C. to a temperature lower than the boiling point of the solvent, and a mixed solvent having a temperature lower than the boiling point of the lowest boiling solvent. Further, the range of 5 ° C. to the boiling point of the solvent ⁇ 5 ° C. is more preferable. At this time, it is necessary to control the ambient atmospheric humidity above the dew point.
- the dope cast on the surface of the metal support 50 as described above has an increased gel film strength (film strength) due to cooling gelation, and further drying is accelerated until stripping. Also, the gel film strength (film strength) increases.
- two or more casting dies 51 may be provided on the metal support 50, and the dope amount may be divided to form a multilayer film.
- the web 1 is dried and solidified on the metal support 50 until the web 1 has a film strength that can be peeled from the metal support 50 by the peeling roll 52. It is preferable to dry the residual solvent amount to 150% by mass or less, and more preferably 80 to 120% by mass.
- the web temperature when peeling the web 1 from the metal support 50 is preferably 0 to 30 ° C. Further, immediately after the web 1 is peeled off from the metal support 50, the temperature rapidly decreases once due to solvent evaporation from the metal support 50 contact surface side, and volatile components such as water vapor and solvent vapor in the atmosphere are condensed. Therefore, the web temperature during peeling is more preferably 5 to 30 ° C.
- the residual solvent amount can be expressed by the following equation.
- Residual solvent amount (% by mass) ⁇ (MN) / N ⁇ ⁇ 100
- M represents the mass of the film at an arbitrary time point
- N represents the mass of the mass M after drying at 110 ° C. for 3 hours.
- the dope film (web) formed by the dope cast on the endless belt metal support 50 is heated on the metal support 50 so that the web can be peeled from the metal support 50 by the peeling roll 52. Evaporate the solvent until.
- the peeling tension is usually 100 N / m to 200 N / m when the metal support 50 and the web 1 are peeled by the peeling roll 52.
- the amount of residual solvent of the web 1 is large at the time of peeling, and the film tends to shrink in the width direction because it tends to stretch in the transport direction.
- shrinkage overlaps the end curls and folds, so that wrinkles easily occur. Therefore, it is preferable to peel with a minimum tension of 170 N / m that can be peeled, more preferably with a minimum tension of 140 N / m. That is.
- the web 1 After drying and solidifying until the web 1 has a peelable film strength on the metal support 50, the web 1 is peeled off by the peeling roll 52.
- the peeled web 1 is introduced into a tenter 53 in the stretching process.
- a tenter 53 in the stretching step a pin tenter and a clip tenter can be used.
- the film for a liquid crystal display device both side edges of the web (or film) 1 are used.
- a clip tenter that is fixed with a clip and stretched is preferable, and it is preferable for improving the flatness and dimensional stability of the film.
- the residual solvent amount of the web (film) 1 immediately before entering the tenter 53 in the stretching step is preferably 10 to 50% by mass.
- the stretch ratio of the web 1 in the tenter 53 is preferably 3 to 80%, and more preferably 6 to 60%.
- the stretch ratio in the width direction of the web 1 in the tenter 53 is less than 3%, it is not preferable because it is impossible to obtain a wide film even with the widest belt or apparatus having a casting width. Further, if the stretching ratio in the width direction of the web 1 in the tenter 53 exceeds 80%, the film is torn depending on the stretching temperature, which is not preferable.
- the hot air blowing means in the stretching step of the present invention specifically refers to a hot air blowing slit port of the tenter 53 in the stretching step, but may be a shape that efficiently heats the film by blowing hot air.
- the temperature of the hot air is preferably 165 to 190 ° C, and more preferably 170 to 185 ° C.
- the stretched film (web) 1 is introduced into a roll transport type drying device 54 and dried while being transported by a transport roller 55 composed of a non-driven free roll in the drying device 54.
- the web 1 is meandered by the conveying rolls 55 arranged in a staggered manner as viewed from the side of 50 to 1000, and the web 1 is dried in the meantime.
- the film transport tension in the drying device 54 is influenced by the physical properties of the dope, the amount of residual solvent in the peeling and film transporting process, the temperature in the drying device 54, etc., but is preferably 30 to 250 N / m, 60 More preferably, 150 N / m. 80 to 120 N / m is most preferable.
- the means for drying the web (or film) 1 is not particularly limited, and is generally performed by hot air, infrared rays, a heating roll, a microwave, or the like. It is preferable to dry with hot air from the viewpoint of simplicity. For example, it is dried by the drying air blown from the warm air inlet at the front portion of the bottom of the drying device 54 and exhausted from the outlet at the rear portion of the ceiling of the drying device 54. It is dried by the wind being discharged.
- the temperature of the drying air is preferably 40 to 160 ° C., more preferably 50 to 160 ° C. in order to improve the flatness and dimensional stability.
- These steps from casting to final post-drying may be performed in an air atmosphere or an inert gas atmosphere such as nitrogen gas.
- an air atmosphere or an inert gas atmosphere such as nitrogen gas.
- the dry atmosphere is carried out in consideration of the explosion limit concentration of the solvent.
- both ends of the film are slit into a product width by a pair of upper and lower slitters 56, 57, cut and cut, and a film is formed in accordance with the product width.
- a roll-shaped optical film is manufactured by forming a knurling portion by winding the kaki no yasoro and winding it.
- the knurling step is to press a plurality of protrusions against the surface of the side end of the film to form a plurality of pairs of protrusions and recesses.
- the height of the projection formed by the film member pushed away by the projection is limited by the flat portion constituting the base of the projection, and the height of the projection is a predetermined height. It is characterized by that. Since this knurling has already been described, the description thereof is omitted here.
- the roll length of the roll film of the optical film produced by the method of the present invention is 500 m or more and 12000 m or less.
- the roll length of the roll-shaped film is 500 m or more, it is not necessary to take much time for switching the rolled-up roll even if the production speed is increased, which is preferable. Moreover, since the frequency of the film switching operation does not increase at the time of polarizing plate processing, productivity is not lowered, which is preferable.
- the roll length of the roll film is 12000 m or less, the load of the core is increased by the weight of the film, and even if the knurling is increased, the convex portion is not easily crushed, and sticking may occur. It is preferable because it is not.
- a film with good dimensional stability can be obtained by setting the residual solvent amount of the film wound by the winder 58 to 0.5% by mass or less, preferably 0.1% by mass or less.
- the optical film of the present invention wound in a roll shape can be produced by the solution casting film forming method.
- FIG. 7 is a flow sheet schematically showing an apparatus for carrying out the method for producing an optical film by the melt casting film forming method of the present invention.
- the thermoplastic resin used is not particularly limited as long as it can be formed by the melt casting film forming method.
- cellulose ester, polycarbonate, alicyclic structure-containing polymer, polyvinyl alcohol, polyamide, polyimide, polyester and the like can be mentioned.
- cellulose esters and alicyclic structure-containing polymers are preferable because of their small photoelastic coefficient, and alicyclic structure-containing polymers are particularly preferable because of their low water absorption.
- the optical film includes an ester plasticizer having a structure in which an organic acid and a trihydric or higher alcohol are condensed as an additive, an ester plasticizer comprising a polyhydric alcohol and a monovalent carboxylic acid, At least one plasticizer selected from ester plasticizers composed of monovalent carboxylic acids and monohydric alcohols, phenolic antioxidants, hindered amine light stabilizers, phosphorus stabilizers, and sulfur stabilizers. It is preferable to contain a stabilizer, and in addition, a peroxide decomposing agent, a radical scavenger, a metal deactivator, an ultraviolet absorber, a matting agent, a dye, a pigment, and other plasticizers and hinders. Antioxidants other than dephenol antioxidants can be included.
- the method for producing an optical film by the melt casting film forming method of the present invention includes a step of feeding a raw material containing a thermoplastic resin into a supply hopper 71, mixing with a mixer 72, and mixing and melting and mixing with an extruder 73.
- a step of tempering a step of casting the melt-kneaded melt from the casting die 74 onto the cooling roll 76, a step of stretching the cast film 70 in the width direction by the tenter 77, and after stretching.
- the step of cutting both ends of the film 70 with the slitters 78 and 79, and the first embossing roll 80 as the first member having the projections on the surface after cutting both ends, and the projections of the first embossing roll A knurling step of knurling both ends of the film 70 by a second embossing roll 81 as a second member having a concave portion substantially similar to the convex portion at a corresponding position; It is and a winding step of winding the film 70.
- the extruder 73 used for film formation may be a single screw extruder or a twin screw extruder.
- a twin-screw extruder When forming a film directly without producing pellets from the material, it is preferable to use a twin-screw extruder because an appropriate degree of kneading is required.
- the screw shape is a Maddock type or Unimelt type. By changing to a kneading type screw such as dull mage, moderate kneading can be obtained and film formation becomes possible.
- both the single-screw extruder and the twin-screw extruder it is desirable to provide a vent port and remove the gas from the vent port using a vacuum pump or the like.
- a vacuum pump or the like In the case of producing a pellet or braided semi-melt, it may be a single screw extruder or a twin screw extruder.
- the cooling step in the extruder 73 and after the extrusion is preferably performed by substituting with an inert gas such as nitrogen gas or reducing the pressure to reduce the oxygen concentration.
- the glass transition temperature (Tg) of the molding material is Tg or more, It is preferable that it is the range of Tg + 100 degrees C or less. More preferably, the melting temperature is Tg + 10 ° C. or higher and Tg + 90 ° C. or lower.
- the melt viscosity at the time of extrusion is 10 to 100,000 poise, preferably 100 to 10,000 poise.
- the residence time of the resin in the extruder 73 is preferably short, and is within 5 minutes, more preferably within 3 minutes, and most preferably within 2 minutes. The residence time depends on the type of extruder 73 and the extrusion conditions, but it can be shortened by adjusting the material supply amount, L / D, screw rotation speed, screw groove depth, etc. It is.
- the shape and rotation speed of the screw of the extruder 73 are appropriately selected depending on the viscosity of the resin, the discharge amount, and the like.
- the shear rate in the extruder 73 is preferably 1 / second to 10,000 / second, more preferably 5 / second to 1000 / second, and most preferably 10 / second to 100 / second.
- a 50/80/100 mesh screen or a metal fiber sintered filter as necessary. It is preferable to use a type that can be changed online.
- the raw materials mixed by the mixer 72 are conveyed to the extruder 73 and heated and melted at, for example, 250 ° C., and the melt is extruded from the casting die 74 according to the present invention.
- the melt extruded from the casting die 74 is cooled and surface-corrected by a stainless steel cooling roll (metal support) 76.
- the film 70 and the cooling roll 76 are preferably in close contact with each other, and the film 70 is pressed by using the touch roll 75 as a method for bringing the film 70 into close contact with the cooling roll 76.
- the temperature of the resin immediately before adhering to the cooling roll 76 is preferably Tg or higher, more preferably Tg + 50 ° C. or higher. By keeping the temperature of the resin high, retardation in the flow direction generated by the elongation of the ribbon can be reduced. It is preferable to keep the temperature of the resin in the air gap immediately before the resin comes into close contact with the cooling roll 76 from the casting die 74 outlet.
- the heat-retaining method induction heating using a microwave, radiant heat heating using an infrared heater, or the like can be preferably used.
- the infrared heater an electric, gas, oil or steam far infrared ceramic heater can be used.
- the cooling rolls 76 may be one or more, but it is preferable to use two or more cooling rolls 76 in order to improve the smoothness on both sides of the film and to bring both sides into contact with the cooling rolls 76. Further, the cooling roll 76 can be provided with cleaning equipment such as a cleaning roll.
- the temperature unevenness of the cooling roll 76 is preferably 0.5 ° C. or less.
- the speed unevenness is preferably 0.5% or less.
- the surface of the cooling roll 76 can use hard chrome plating, but is not limited to this.
- the surface roughness is preferably 0.1 s or less.
- the material of the touch roll 75 a metal or a material obtained by winding a resin, rubber or the like around a metal roll can be used. Further, a crown roll having a diameter changed as it goes from the width central portion to the side can also be used.
- the temperature immediately before being in close contact with the touch roll 75 is preferably not less than the glass transition temperature (Tg) of the resin, and more preferably not less than Tg + 50 ° C.
- the temperature of the cooling roll 76 is preferably adjusted by flowing a heat medium such as water or oil through the cooling roll 76.
- the cooled and solidified film is peeled off from the cooling roll 76 and stretched in the width direction.
- the molecules are oriented by stretching.
- a stretching method a known tenter 77 or the like can be preferably used.
- the stretching is preferably performed under a controlled uniform temperature distribution.
- the temperature is preferably within ⁇ 2 ° C, more preferably within ⁇ 1 ° C, and particularly preferably within ⁇ 0.5 ° C.
- the film may be stretched or shrunk in the longitudinal direction or the width direction.
- the film is contracted by temporarily stretching out the width stretching and relaxing in the longitudinal direction, or by gradually narrowing the interval between adjacent clips of the transverse stretching machine.
- the latter method can be performed by using a general simultaneous biaxial stretching machine and driving the clip portions in the longitudinal direction by, for example, a pantograph method or a linear drive method to smoothly and gradually narrow the clip portion. it can. You may combine with extending
- the dimensional change rate of the optical film can be reduced by shrinking 0.5% to 10% in both the longitudinal direction and the width direction.
- the film thickness variation of the optical film is preferably in the range of ⁇ 3%, more preferably ⁇ 1%.
- a method of stretching in the biaxial directions perpendicular to each other is effective, and the stretching ratios in the biaxial directions perpendicular to each other are finally 1.0 to 2.
- the range is preferably 0 times and 1.01 to 2.5 times in the width direction, 1.01 to 1.5 times in the casting direction, and 1.05 to 2.0 times in the width direction. It is preferable to carry out with.
- the method of stretching the film For example, a difference in circumferential speed is applied to a plurality of rolls, and the roll is stretched in the longitudinal direction using the circumferential speed difference between the rolls. Both ends of the film 70 are clipped or pinned. Examples include a method of fixing and widening the gap between clips and pins in the traveling direction and extending in the vertical direction, a method of expanding in the horizontal direction and extending in the horizontal direction, or a method of extending both in the vertical and horizontal directions and extending in both the vertical and horizontal directions. . Further, these methods may be used in combination.
- both ends of the film are slit and cut into a product width by a pair of upper and lower slitters 78, 79, and a film is formed according to the product width.
- a knurling process is performed to form a knurling portion, and a roll-shaped optical film is manufactured by winding with a winding device 82.
- the knurling step is to press a plurality of protrusions against the surface of the side end of the film to form a plurality of pairs of protrusions and recesses.
- the height of the projection formed by the film member pushed away by the projection is limited by the flat portion constituting the base of the projection, and the height of the projection is a predetermined height. It is characterized by that. Since this knurling has already been described, the description thereof is omitted here.
- the optical film of the present invention wound into a roll by the melt casting film forming method can be produced.
- the winding method of the film may be a commonly used winder in any of the solution casting film forming method and the melt casting film forming method, a constant torque method, There are methods for controlling the tension, such as a constant tension method, a taper tension method, and a program tension control method with a constant internal stress.
- the polarizing plate can be produced by a general method.
- the back side of the optical film of the present invention is subjected to alkali saponification treatment, and the treated optical film is bonded to at least one surface of a polarizing film produced by immersing and stretching in an iodine solution using a completely saponified polyvinyl alcohol aqueous solution. It is preferable.
- the optical film may be used on the other surface, or another polarizing plate protective film may be used.
- the polarizing plate protective film used on the other surface of the optical film of the present invention preferably has an in-plane retardation Ro of 590 nm, a phase difference of 20 to 70 nm, and Rt of 100 to 400 nm. These can be created, for example, by the method described in JP-A-2002-71957.
- the optically anisotropic layer can be formed by the method described in JP-A-2003-98348.
- KC8UX2MW, KC4UX, KC5UX, KC4UY, KC8UY, KC12UR, KC8UCR-3 (manufactured by Konica Minolta Opto Co., Ltd.) and the like are preferably used as a commercially available transparent support.
- the polarizing film which is the main component of the polarizing plate, is an element that transmits only light having a polarization plane in a certain direction.
- a typical polarizing film known at present is a polyvinyl alcohol polarizing film, which is a polyvinyl alcohol film.
- iodine is dyed on a system film and one in which dichroic dye is dyed.
- a polyvinyl alcohol aqueous solution is formed and dyed by uniaxially stretching or dyed, or uniaxially stretched after dyeing, and then preferably subjected to a durability treatment with a boron compound.
- On the surface of the polarizing film one side of the optical film of the present invention is bonded to form a polarizing plate. It is preferably bonded with an aqueous adhesive mainly composed of completely saponified polyvinyl alcohol or the like.
- the polarizing plate using the conventional optical film is inferior in flatness, and when the reflected image is seen, fine wavy unevenness is recognized, and the wavy unevenness is increased by the durability test under the conditions of 60 ° C. and 90% RH.
- the polarizing plate using the optical film of the present invention was excellent in flatness.
- the wavy unevenness does not increase, and even with a polarizing plate having an optical compensation film on the back surface side, the viewing angle characteristics after the durability test are It was possible to provide good visibility without fluctuation. (Display device)
- various display devices with excellent visibility can be manufactured.
- the optical film of the present invention is preferably a reflective, transmissive, transflective LCD, or TN, STN, OCB, HAN, VA (PVA, MVA), IPS, or other driving LCD.
- the antireflection film of the present invention has very little uneven color of reflected light of the antireflection layer, and has excellent flatness, and various displays such as a plasma display, a field emission display, an organic EL display, an inorganic EL display, and electronic paper. It is also preferably used for an apparatus.
- a large-screen display device with a 30-inch screen or more has the effect that there is little unevenness in color and undulation, and eyes are not tired even during long-time viewing.
- Examples 1 to 17 and Comparative Examples 1 to 8 A cellulose triacetate film was produced as follows by the method for producing an optical film by the solution casting method of the present invention.
- Dope composition 1 Cellulose triacetate 100 parts by mass Triphenyl phosphate 8 parts by mass Ethylphthalyl ethyl glycolate 2 parts by mass Methylene chloride 440 parts by mass Ethanol 40 parts by mass Tinuvin 109 (manufactured by Ciba Japan Co., Ltd.) 0.5 parts by mass Tinuvin 171 (Ciba 0.5 mass part Aerosil 972V (manufactured by Nippon Aerosil Co., Ltd.) 0.2 mass part
- the material of the above dope composition 1 is put into an airtight container, heated, stirred and completely dissolved. And filtered.
- the dope was uniformly cast to a width of 1800 mm on a stainless steel band support having a width of 2000 mm at a temperature of 35 ° C. using the solution casting film forming apparatus shown in FIG.
- cellulose triacetate having different molecular weight distributions and having two kinds of glass transition temperatures Tg (° C.) shown in Table 1 were used.
- the solvent was evaporated until the residual solvent amount reached 100% by mass, and the web was peeled from the stainless steel band support.
- both ends of the web in the width direction (TD direction) were held with a tenter, and the web was stretched in the width direction of the web at a stretching ratio of 10%.
- the residual solvent amount of the web immediately before entering the tenter of the stretching process was 30% by mass.
- the stretched film is introduced into a drying apparatus, and the film is subjected to 500 non-drivings made of mirror conveying rolls (surface length 2200 mm, diameter 110 mm) having a surface roughness (Rmax) of 0.8 ⁇ m in the drying apparatus. It dried while conveying with the conveyance roll comprised with a free roll.
- the film transport tension in the drying apparatus was 80 N / m.
- drying was performed by a drying air having a temperature of 150 ° C. blown from a hot air inlet at a front portion of the bottom of the drying device.
- both ends of the film were slit to 1600 mm in width by a pair of upper and lower slitters, and cut and cut.
- the knurling process was performed with an embossing roll 61 having a protrusion on the surface, and a backup roll 62 arranged opposite to the embossing roll 61 with a film interposed therebetween.
- FIG. 8 shows the cross-sectional shape of the protrusion used for the embossing roll 61.
- the bottom surface has a length L1 on one side and a quadrangle having a side with the same length as or different from L1, and the surface of the tip has the same length as or different from the length L2 on one side and L2.
- a knurling process was performed using a quadrangular pyramid having a side and a height of h. At this time, the height of the convex portion formed on the film surface is limited by the flat portion constituting the base portion of the protruding portion.
- the number of irregularities formed on the surface of the knurling part was set to the number shown in Table 1.
- the optical film was wound on a cylindrical tube having a diameter of 600 mm to produce optical films of Examples 1 to 17 and Comparative Examples 1 to 8 having a length of 3000 m, a thickness of 50 ⁇ mm, and a width of m 1600.
- evaluation With respect to the optical films of Examples 1 to 17 and Comparative Examples 1 to 8 produced by the above method, the presence or absence of black bands in the roll state was visually observed.
- the product has a level that is not a problem as a product, the symbol “ ⁇ ” indicates that the product is acceptable, “ ⁇ ” indicates that the product is acceptable, and ⁇ indicates the product that is frequently recognized.
- Example 3 comparing Example 3 with Examples 10 to 13, it can be seen that the ratio S / Y between the sectional area S ⁇ m 2 and the widest width Y ⁇ m of the recess is preferably 10 to 300. Further, when Example 3 and Examples 14 to 17 are compared, it is found that a pair of irregularities is preferably formed at 10 to 300 / cm 2 in the knurled region.
- polarizing plates were prepared as follows, and these polarizing plates were incorporated into a liquid crystal display panel (liquid crystal display device) for visual recognition. Sex was evaluated.
- each of the optical films of Examples 1 to 17 and Comparative Examples 1 to 8 and one KC8UCR5 (manufactured by Konica Minolta Opto), which is a cellulose ester optical compensation film, was used as a polarizing plate protective film.
- the polarizing plate of this invention and the polarizing plate of a comparative example were produced.
- PVA polyvinyl alcohol
- the film was extruded from a T die onto a metal roll to form a film. Then, it dried and heat-processed and obtained the PVA film.
- the obtained PVA film had an average thickness of 40 ⁇ m, a moisture content of 4.4%, and a film width of 3 m.
- the PVA film was successively treated in the order of pre-swelling, dyeing, uniaxial stretching by a wet method, fixing treatment, drying, and heat treatment described below to produce a polarizing film.
- the PVA film was pre-swelled by immersing it in water at 30 ° C. for 30 seconds and immersed in an aqueous solution at 35 ° C. having an iodine concentration of 0.4 g / liter and a potassium iodide concentration of 40 g / liter for 3 minutes. Subsequently, the film was uniaxially stretched 6 times in an aqueous solution of boric acid concentration 4% at 50 ° C. under a tension of 700 N / m. The potassium iodide concentration 40 g / liter, boric acid concentration 40 g / liter, Fixation was performed by immersing in an aqueous solution at 30 ° C.
- Step 1 The optical compensation film and the optical film were immersed in a 3 mol / L sodium hydroxide solution at 60 ° C. for 90 seconds, then washed with water and dried.
- the optical compensation film was immersed in a 3 mol / L sodium hydroxide solution at a temperature of 60 ° C. for 90 seconds, then washed with water and dried.
- Step 2 The above polarizing film was immersed in a polyvinyl alcohol adhesive tank having a solid content of 2% by mass for 1 to 2 seconds.
- Step 3 Excess adhesive adhered to the polarizing film film in Step 2 was lightly removed, and it was sandwiched between the optical compensation film and the optical film that had been subjected to alkali treatment in Step 1 and laminated.
- Process 4 The two rotating rollers were bonded together at a pressure of 20 to 30 N / cm 2 and a speed of about 2 m / min. At this time, care was taken to prevent bubbles from entering.
- Step 5 The sample produced in Step 4 was dried for 2 minutes in a dryer at a temperature of 80 ° C. to produce a plate.
- the polarizing plate on the outermost surface of a commercially available liquid crystal display panel (VA type) was carefully peeled off, and the polarizing plate of the present invention in which the polarization direction was matched, and the polarizing plate of the comparative example were attached thereto.
- VA type liquid crystal display panel
- the liquid crystal panel of the present invention obtained as described above and the liquid crystal panel of the comparative example are arranged on a desk having a height of 80 cm from the floor, and a daylight direct tube fluorescent lamp is placed on a ceiling portion having a height of 3 m from the floor.
- FLR40S • D / MX manufactured by Matsushita Electric Industrial Co., Ltd.
- Ten sets of 40W ⁇ 2 pieces were arranged at 1.5 m intervals as one set.
- the fluorescent lamp is arranged so that the fluorescent lamp comes to the ceiling from the evaluator's overhead to the rear.
- the liquid crystal panel was tilted by 25 ° from the vertical direction with respect to the desk so that the fluorescent lamp was reflected, and the visibility (visibility) of the screen was ranked and evaluated as follows.
Abstract
Description
前記一対の凹凸の前記凸部を、該凸部の前記フィルムの表面から平均高さの1/2のところで前記フィルムの表面と平行な平面で切断したとき、前記凸部の1つ当たりの断面積Sが、2500~10000μm2で、前記凸部の平均幅Wが3~20μmであることを特徴とする光学フィルム。
前記断面積Sμm2と前記凸部の前記フィルムの表面からの平均高さHμmとの比S/Hが、100~3000であることを特徴とする前記1に記載の光学フィルム。
前記断面積Sμm2と前記凹部の最も広い幅Yμmとの比S/Yが、10~300であることを特徴とする前記1又は2に記載の光学フィルム。
前記1から4の何れか1項の光学フィルムを製造する方法において、
前記ナーリングを付与する工程は、
前記突起部を前記フィルムの表面に押しつけた際に、前記突起部により押しのけられたフィルム部材により形成される凸部の高さを、前記突起部の基部を構成する平坦部で制限し、前記凸部の高さを所定の高さにすることを特徴とする光学フィルムの製造方法。
カラム:Shodex K806、K805、K803G(昭和電工株式会社製を3本接続して使用した)
カラム温度:25℃
試料濃度:0.1質量%
検出器:RI Model 504(GLサイエンス社製)
ポンプ:L6000(日立製作所株式会社製)
流量:1.0ml/分
校正曲線:標準ポリスチレンSTK standard ポリスチレン(東ソー株式会社製)Mw=1,000,000~500迄の13サンプルによる校正曲線を使用した。13サンプルは、ほぼ等間隔に用いることが好ましい。
一般式(2) B2-(G-A-)nG-B2
上記式中、B1はモノカルボン酸成分を表わし、B2はモノアルコール成分を表わし、Gは2価のアルコール成分を表わし、Aは2塩基酸成分を表わし、これらによって合成されたことを表わす。B1、B2、G、およびAは、いずれも芳香環を含まないことが特徴である。m、nは、繰り返し数を表わす。
(ただし、R1はn価の有機基、nは2以上の正の整数を表す)
好ましい多価アルコールの例としては、例えば以下のようなものを挙げることができるが、本発明はこれらに限定されるものではない。
式中、Mは、フィルムの任意時点での質量、Nは、質量Mのものを110℃で3時間乾燥させた後の質量を表わす。
(偏光板)
偏光板は一般的な方法で作製することが出来る。本発明の光学フィルムの裏面側をアルカリ鹸化処理し、処理した光学フィルムを、ヨウ素溶液中に浸漬延伸して作製した偏光膜の少なくとも一方の面に、完全鹸化型ポリビニルアルコール水溶液を用いて貼り合わせることが好ましい。もう一方の面にも該光学フィルムを用いても、別の偏光板保護フィルムを用いてもよい。本発明の光学フィルムに対して、もう一方の面に用いられる偏光板保護フィルムは面内リタデーションRoが590nmで、20~70nm、Rtが100~400nmの位相差を有していることが好ましい。これらは例えば、特開2002-71957号公報記載の方法で作成することが出来る。或いは更にディスコチック液晶等の液晶化合物を配向させて形成した光学異方層を有している光学補償フィルムを兼ねる偏光板保護フィルムを用いることが好ましい。例えば、特開2003-98348号公報記載の方法で光学異方性層を形成することが出来る。本発明の光学フィルムと組み合わせて使用することによって、平面性に優れ、安定した視野角拡大効果を有する偏光板を得ることが出来る。
(表示装置)
上記偏光板を表示装置に組み込むことによって、種々の視認性に優れた表示装置を作製することが出来る。本発明の光学フィルムは反射型、透過型、半透過型LCD或いはTN型、STN型、OCB型、HAN型、VA型(PVA型、MVA型)、IPS型等の各種駆動方式のLCDで好ましく用いられる。また、本発明の反射防止フィルムは反射防止層の反射光の色むらが著しく少なく、また、平面性に優れ、プラズマディスプレイ、フィールドエミッションディスプレイ、有機ELディスプレイ、無機ELディスプレイ、電子ペーパー等の各種表示装置にも好ましく用いられる。特に画面が30型以上の大画面の表示装置では、色むらや波打ちむらが少なく、長時間の鑑賞でも目が疲れないという効果があった。
実施例1~17、比較例1~8
本発明の溶液流延製膜法による光学フィルムの製造方法により、セルローストリアセテートフィルムを、つぎのようにして作製した。
(ドープ組成1)
セルローストリアセテート 100質量部
トリフェニルホスフェート 8質量部
エチルフタリルエチルグリコレート 2質量部
メチレンクロライド 440質量部
エタノール 40質量部
チヌビン109(チバ・ジャパン(株)製) 0.5質量部
チヌビン171(チバ・ジャパン(株)製) 0.5質量部
アエロジル972V(日本アエロジル株式会社製) 0.2質量部
上記のドープ組成1の材料を、密閉容器に投入し、加熱し、撹拌しながら、完全に溶解し、濾過した。濾過は、フィルタープレスによる濾過の後、金属焼結フィルター(捕捉粒子径=10ミクロン)を通過させた。ついで、ドープを、図6に示す溶液流延製膜装置を用い、温度35℃で、幅2000mmのステンレスバンド支持体上に幅1800mmに均一に流延した。また、セルローストリアセテートの分子量分布の違うものを用いて、表1に示す2種類のガラス転移温度Tg(℃)を示すものを用いた。
(評価)
上記の方法により作製した実施例1~17、比較例1~8の光学フィルムについて、ロール状態でのブラックバンドの発生の有無を目視により観察し、全く認められないものをまる◎、わずかに認められるが製品として問題ないレベルのものを○、認められるものを△、多く認められるものを×とした。また、ロール状態から光学フィルムを繰り出したときのブロッキングの発生の有無を観察し、全く認められないものをまる◎、わずかに認められるが製品として問題ないレベルのものを○、認められるものを△、フィルムの変形、破れが発生したものを×とした。ブラックバンドやブロッキングが△レベルで観察されると、フィルムにシワや異物が発生し、製品としては使用できない。評価結果を表1に示す。
(a)偏光膜の作製
けん化度99.95モル%、重合度2400のポリビニルアルコール(以下PVAと略す)100質量部に、グリセリン10質量部、及び水170質量部を含浸させたものを溶融混練し、脱泡後、Tダイから金属ロール上に溶融押出し、製膜した。その後、乾燥・熱処理してPVAフィルムを得た。得られたPVAフィルムは平均厚みが40μm、水分率が4.4%、フィルム幅が3mであった。
(b)偏光板の作製
ついで、下記工程1~5に従って、偏光膜フィルムと偏光板用保護フィルムとを貼り合わせて本発明の偏光板、及び比較例の偏光板を作製した。
(視認性評価)
上記のようにして得られた本発明の液晶パネル、及び比較例の液晶パネルを、床から80cmの高さの机上に配置し、床から3mの高さの天井部に昼色光直管蛍光灯(FLR40S・D/M-X 松下電器産業株式会社製)40W×2本を1セットとして1.5m間隔で10セット配置した。このとき、評価者が液晶パネル表示面正面にいるときに、評価者の頭上より後方に向けて天井部に前記蛍光灯がくるように配置した。液晶パネルは机に対する垂直方向から25°傾けて蛍光灯が写り込むようにして、画面の見易さ(視認性)を下記のようにランク分けして、評価した。
B:近くの蛍光灯の写り込みはやや気になるが、遠くは気にならず、フォントの大きさ8以下の文字もなんとかと読める
C:遠くの蛍光灯の写り込みも気になり、フォントの大きさ8以下の文字を読むのは困難である
D:蛍光灯の写り込みがかなり気になり、写り込みの部分はフォントの大きさ8以下の文字を読むことはできない
評価の結果、本発明の実施例1~17で作製した光学フィルムを用いた偏光板を組み込んだ液晶パネルは、何れもランクB以上の評価結果であり、良好であった。これに対し、比較例1~8で作製した光学フィルムを用いた偏光板を組み込んだ液晶パネルは、ランクDの評価結果であった。
12 ナーリング加工面
13 凸部
14 凹部
21 平坦部
50 金属製支持体
51、74 流延ダイ
52 剥離ロール
53、77 テンター
54 乾燥装置
55 搬送ロール
56、57、78、79 スリッター
58、82 巻取り装置
61、80 エンボスロール
62、81 バックアップロール
71 供給ホッパー
72 混合機
73 押出機
75 タッチロール
76 冷却ロール
Claims (7)
- 長尺状のフィルムの幅方向の両側端部に、凹部と凹部の周囲に形成された凸部とを一対とする凹凸を複数形成された光学フィルムにおいて、
前記一対の凹凸の前記凸部を、該凸部の前記フィルムの表面から平均高さの1/2のところで前記フィルムの表面と平行な平面で切断したとき、前記凸部の1つ当たりの断面積Sが、2500~10000μm2で、前記凸部の平均幅Wが3~20μmであることを特徴とする光学フィルム。 - 前記一対の凹凸において、
前記断面積Sμm2と前記凸部の前記フィルムの表面からの平均高さHμmとの比S/Hが、100~3000であることを特徴とする請求項1に記載の光学フィルム。 - 前記一対の凹凸において、
前記断面積Sμm2と前記凹部の最も広い幅Yμmとの比S/Yが、10~300であることを特徴とする請求項1又は2に記載の光学フィルム。 - 前記フィルムの幅方向の両側端部に、前記一対の凹凸が、10~300個/cm2形成されていることを特徴とする請求項1から3の何れか1項に記載の光学フィルム。
- 長尺状のフィルムの幅方向の両側端部に複数の突起部を有する部材を押しつけて、凹凸によるナーリングを付与する工程と、前記フィルムを巻きとる工程と、を有し、
請求項1から4の何れか1項の光学フィルムを製造する方法において、
前記ナーリングを付与する工程は、前記突起部を前記フィルムの表面に押しつけた際に、前記突起部により押しのけられたフィルム部材により形成される凸部の高さを、前記突起部の基部を構成する平坦部で制限し、前記凸部の高さを所定の高さにすることを特徴とする光学フィルムの製造方法。 - 偏光子の表面に、請求項1から4の何れか1項に記載の光学フィルムを配置したことを特徴とする偏光板。
- 請求項6に記載の偏光板を配置したことを特徴とする液晶表示装置。
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KR (1) | KR20120070566A (ja) |
CN (1) | CN102483481B (ja) |
WO (1) | WO2011030684A1 (ja) |
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JP2013049245A (ja) * | 2011-08-31 | 2013-03-14 | Fujifilm Corp | ポリマーフィルム |
JP2015060143A (ja) * | 2013-09-20 | 2015-03-30 | 大日本印刷株式会社 | 光学フィルム、および、その製造方法 |
WO2016109205A1 (en) | 2014-12-30 | 2016-07-07 | 3M Innovative Properties Company | Web-wound rolls with microsphere treated edge and methods of making same |
WO2017150352A1 (ja) * | 2016-02-29 | 2017-09-08 | 日本ゼオン株式会社 | ナール構造付きフィルム及び製造方法 |
WO2019097977A1 (ja) * | 2017-11-17 | 2019-05-23 | 東レ株式会社 | フィルム、それを用いた成型転写箔、フィルムロール、及びフィルムの製造方法 |
KR20210151754A (ko) * | 2014-12-11 | 2021-12-14 | 닛토덴코 가부시키가이샤 | 편광막 제조용의 적층체 |
KR20220160605A (ko) | 2020-03-31 | 2022-12-06 | 도요보 가부시키가이샤 | 널 가공이 실시된 장척상 수지 필름 |
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JP6285176B2 (ja) * | 2013-12-25 | 2018-02-28 | 日東電工株式会社 | 光学積層体の製造方法 |
JP6370190B2 (ja) * | 2014-10-24 | 2018-08-08 | 住友化学株式会社 | 偏光板ロール |
KR101854156B1 (ko) * | 2015-07-10 | 2018-06-14 | 동우 화인켐 주식회사 | 하드코팅 필름, 이를 포함하는 편광판 및 화상 표시 장치 |
JP2017100372A (ja) | 2015-12-02 | 2017-06-08 | コニカミノルタ株式会社 | フィルムロールの製造方法 |
JP6076523B1 (ja) * | 2016-02-25 | 2017-02-08 | 住友化学株式会社 | 積層光学フィルムの製造方法 |
WO2020110819A1 (ja) * | 2018-11-28 | 2020-06-04 | 富士フイルム株式会社 | 光学積層フィルムロールの製造方法、および、光学積層フィルムロール |
JP7427897B2 (ja) * | 2019-09-27 | 2024-02-06 | コニカミノルタ株式会社 | フィルムロール及びその製造方法 |
JP7084432B2 (ja) * | 2020-01-14 | 2022-06-14 | 日東電工株式会社 | フィルムロールの製造システム、および、フィルムロールの製造方法 |
KR102323531B1 (ko) | 2020-11-04 | 2021-11-09 | 이동하 | 휴대용 젖병세척장치 |
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Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2013049245A (ja) * | 2011-08-31 | 2013-03-14 | Fujifilm Corp | ポリマーフィルム |
JP2015060143A (ja) * | 2013-09-20 | 2015-03-30 | 大日本印刷株式会社 | 光学フィルム、および、その製造方法 |
KR20210151754A (ko) * | 2014-12-11 | 2021-12-14 | 닛토덴코 가부시키가이샤 | 편광막 제조용의 적층체 |
KR102577828B1 (ko) * | 2014-12-11 | 2023-09-12 | 닛토덴코 가부시키가이샤 | 편광막 제조용의 적층체 |
WO2016109205A1 (en) | 2014-12-30 | 2016-07-07 | 3M Innovative Properties Company | Web-wound rolls with microsphere treated edge and methods of making same |
WO2017150352A1 (ja) * | 2016-02-29 | 2017-09-08 | 日本ゼオン株式会社 | ナール構造付きフィルム及び製造方法 |
JPWO2017150352A1 (ja) * | 2016-02-29 | 2018-12-27 | 日本ゼオン株式会社 | ナール構造付きフィルム及び製造方法 |
WO2019097977A1 (ja) * | 2017-11-17 | 2019-05-23 | 東レ株式会社 | フィルム、それを用いた成型転写箔、フィルムロール、及びフィルムの製造方法 |
JPWO2019097977A1 (ja) * | 2017-11-17 | 2020-11-19 | 東レ株式会社 | フィルム、それを用いた成型転写箔、フィルムロール、及びフィルムの製造方法 |
JP7221695B2 (ja) | 2017-11-17 | 2023-02-14 | 東レ株式会社 | フィルム、それを用いた成型転写箔、フィルムロール、及びフィルムの製造方法 |
KR20220160605A (ko) | 2020-03-31 | 2022-12-06 | 도요보 가부시키가이샤 | 널 가공이 실시된 장척상 수지 필름 |
Also Published As
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CN102483481A (zh) | 2012-05-30 |
JP5510459B2 (ja) | 2014-06-04 |
KR20120070566A (ko) | 2012-06-29 |
CN102483481B (zh) | 2015-04-08 |
JPWO2011030684A1 (ja) | 2013-02-07 |
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