WO2012008242A1 - Liquid crystal display device - Google Patents
Liquid crystal display device Download PDFInfo
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- WO2012008242A1 WO2012008242A1 PCT/JP2011/063032 JP2011063032W WO2012008242A1 WO 2012008242 A1 WO2012008242 A1 WO 2012008242A1 JP 2011063032 W JP2011063032 W JP 2011063032W WO 2012008242 A1 WO2012008242 A1 WO 2012008242A1
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- polarizing plate
- film
- liquid crystal
- cellulose ester
- display device
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
- G02F1/133528—Polarisers
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/30—Polarising elements
- G02B5/3025—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state
- G02B5/3033—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid
- G02B5/3041—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid comprising multiple thin layers, e.g. multilayer stacks
- G02B5/305—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid comprising multiple thin layers, e.g. multilayer stacks including organic materials, e.g. polymeric layers
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/30—Polarising elements
- G02B5/3083—Birefringent or phase retarding elements
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
- G02F1/1336—Illuminating devices
- G02F1/133602—Direct backlight
- G02F1/133603—Direct backlight with LEDs
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F2201/00—Constructional arrangements not provided for in groups G02F1/00 - G02F7/00
- G02F2201/08—Constructional arrangements not provided for in groups G02F1/00 - G02F7/00 light absorbing layer
- G02F2201/086—UV absorbing
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F2201/00—Constructional arrangements not provided for in groups G02F1/00 - G02F7/00
- G02F2201/50—Protective arrangements
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F2203/00—Function characteristic
- G02F2203/01—Function characteristic transmissive
Definitions
- the present invention relates to a liquid crystal display device having an LED backlight.
- a protective film is usually bonded to both surfaces of a polarizer having polarizing ability via an adhesive layer.
- the polarizing performance of the polarizing plate fluctuates when the polarizing plate is exposed to heat and humidity due to long-term use, and further, the display performance of the liquid crystal display device deteriorates.
- liquid crystal display devices are used in various ways, and durability is required not only in high-temperature and high-humidity environments, but also in low-temperature and high-humidity environments. -It has been found that the durability of the polarizing plate in a high-humidity environment is improved, so that the durability in other environments may be impaired.
- An object of the present invention is to provide a liquid crystal display device having an optical film group that does not cause reddish discoloration in a polarizing plate and does not deteriorate display image quality in a liquid crystal display device using an LED as a backlight.
- a viewing side polarizing plate having a structure sandwiched between two polarizing plate protective films, a liquid crystal cell, a backlight side polarizing plate having a structure sandwiched between two polarizing plate protective films, and an LED backlight
- the two polarizing plate protective films of the viewing side polarizing plate are both cellulose ester films
- the polarizing plate protective film on the liquid crystal cell side of the backlight side polarizing plate Is a cellulose ester film.
- a liquid crystal display device using an LED as a backlight it is possible to obtain a liquid crystal display device that does not cause reddish discoloration in the polarizing plate and does not deteriorate display image quality.
- the liquid crystal display device of the present invention is a viewing side polarizing plate having a structure sandwiched between two polarizing plate protective films, a liquid crystal cell, a backlight side polarizing plate having a structure sandwiched between two polarizing plate protective films, And the LED backlight in this order from the viewing side, the two polarizing plate protective films of the viewing side polarizing plate are both cellulose ester films, and the liquid crystal cell of the backlight side polarizing plate
- the polarizing plate protective film on the side is a cellulose ester film.
- FIG. 1 is a schematic view of a basic liquid crystal display device of the present invention.
- the backlight is an LED, and in that case, a polarizing plate protective film T1 (viewing side polarizing plate protective film of the viewing side polarizing plate) and T2 (liquid crystal cell side polarizing plate protection of the viewing side polarizing plate).
- Film) and T3 (liquid crystal cell side polarizing plate protective film of the backlight side polarizing plate) are cellulose ester films.
- a cellulose acetate film having an acetyl group substitution degree X of T2 of 2.1 ⁇ X ⁇ 2.5 is preferable.
- cellulose ester film As the main component of the cellulose ester film of T1 to T3 of the present invention, cellulose triacetate, cellulose diacetate, cellulose acetate butyrate, and cellulose acetate propionate are preferable, and among these, cellulose diacetate is preferably used.
- the cellulose ester film of T1 of the present invention is X, Y when the substitution degree of acetyl groups is X and the substitution degree of other acyl groups is Y, particularly from the viewpoint of optical isotropy required for a polarizing plate protective film.
- a cellulose triacetate film is preferable.
- Another resin may be mixed as long as the function of the present invention is not impaired, and various additives may be added according to the purpose.
- T1 a commercially available cellulose triacetate film used with a normal polarizing plate protective film can be used.
- the cellulose ester film of T2 and T3 of the present invention has high retardation development and can be made into a thin film even when it is a retardation film having a high retardation, stretching for expressing the retardation. From the viewpoint of keeping the magnification low, a film made of cellulose ester that satisfies the range of the following formula is used.
- the cellulose ester film of T2 and T3 of the present invention is preferably a cellulose acetate film in which T2 is 2.1 ⁇ X ⁇ 2.5, and T2 and T3 are simultaneously 2.1 ⁇ X ⁇ 2.5. Most preferred is a cellulose diacetate film.
- the cellulose acetate films T2 and T3 of the present invention can appropriately adjust the retardation required for the required optical compensation effect, and from the viewpoint of taking advantage of high retardation development, retardation Ro in the in-plane direction.
- Is preferably 30 nm or more, more preferably in the range of 30 to 200 nm
- the retardation Rth in the thickness direction is preferably 70 nm or more, and more preferably in the range of 70 to 300 nm.
- the method of adjusting the phase difference is not particularly limited, but a method of adjusting by stretching is common. A detailed adjustment method will be described later.
- cellulose acetates used for the polarizing plate protective film and the retardation film of the present invention can be synthesized by a known method.
- the cellulose used as a raw material of cellulose acetate used in the retardation film and polarizing plate protective film of the present invention is not particularly limited, and examples thereof include cotton linters, wood pulp (derived from coniferous trees, derived from hardwoods), kenaf and the like. . Moreover, the cellulose acetate obtained from them can be mixed and used in arbitrary ratios, respectively.
- the cellulose acetate of the present invention can be produced by a known method. Specifically, it can be synthesized with reference to the method described in JP-A-10-45804.
- a dope preparation method a method of preparing at a temperature of 0 ° C. or higher (normal temperature or high temperature) and a cooling preparation method of preparing at a low temperature are known.
- a halogenated hydrocarbon particularly methylene chloride
- the Invention Association public technique public technical number 2001-1745, published on March 15, 2001, hereinafter abbreviated as public technique 2001-1745
- paragraphs 12 to 15 the preparation method is described in the items 22 to 25.
- the viscosity of the cellulose acetate solution of the present invention is preferably 15 to 140 Pa ⁇ s, and the temperature of the dope during dissolution and filtration is preferably 20 ° C. or higher and 30 ° C. or lower. More preferably, the viscosity of the low-viscosity cellulose acetate solution is 30 to 90 Pa ⁇ s.
- the viscosity of the cellulose acetate solution of the present invention can be measured at 25 ° C. using a B-type viscometer Model VS-A1 (Shibaura System Co., Ltd.) according to the method described in JIS Z 8803.
- the molecular weight of the cellulose ester is preferably 100,000 to 200,000, more preferably 130,000 to 160,000 in terms of weight average molecular weight (Mw).
- the cellulose acetate used in the present invention preferably has a Mn / Mw ratio of 1.0 or more and less than 5.0, more preferably 2.5 or more and less than 4.0.
- the degree of polymerization of cellulose acetate is preferably 200 to 800, more preferably 250 to 650, still more preferably 250 to 450, and particularly preferably 250 to 400 in terms of viscosity average degree of polymerization.
- the viscosity average degree of polymerization can be measured according to Uda et al.'S limiting viscosity method (Kazuo Uda, Hideo Saito, Journal of Textile Science, Vol. 18, No. 1, pp. 105-120, 1962). A method for measuring the viscosity average degree of polymerization is also described in JP-A-9-95538.
- the cellulose ester film of the present invention preferably contains a sugar ester compound represented by the general formula (1) as a physical property improving agent.
- the cellulose ester film of the present invention preferably contains an ester compound represented by the general formula (2) as a plasticizer.
- the alkylene glycol component having 2 to 12 carbon atoms includes ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,2-propanediol, 2-methyl 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propan
- the compound represented by the general formula (1) or (2) can be appropriately used in the range of 1 to 40% by mass of the cellulose ester film.
- the cellulose acetate film of the present invention can contain a plasticizer other than the compounds represented by the general formulas (1) and (2) as necessary for obtaining the effects of the present invention.
- the plasticizer is not particularly limited, but is preferably a polycarboxylic acid ester plasticizer, a glycolate plasticizer, a phthalate ester plasticizer, a fatty acid ester plasticizer, a polyhydric alcohol ester plasticizer, or an ester plasticizer. Agent, acrylic plasticizer and the like.
- At least one is preferably a polyhydric alcohol ester plasticizer.
- the polyhydric alcohol ester plasticizer is a plasticizer composed of an ester of a divalent or higher aliphatic polyhydric alcohol and a monocarboxylic acid, and preferably has an aromatic ring or a cycloalkyl ring in the molecule.
- a divalent to 20-valent aliphatic polyhydric alcohol ester is preferred.
- the polyhydric alcohol preferably used in the present invention is represented by the following general formula (a).
- R 11 represents an n-valent organic group
- n represents a positive integer of 2 or more
- the OH group represents an alcoholic and / or phenolic hydroxyl group.
- the glycolate plasticizer is not particularly limited, but alkylphthalylalkyl glycolates can be preferably used.
- alkyl phthalyl alkyl glycolates include methyl phthalyl methyl glycolate, ethyl phthalyl ethyl glycolate, propyl phthalyl propyl glycolate, butyl phthalyl butyl glycolate, octyl phthalyl octyl glycolate, methyl phthalyl ethyl Glycolate, ethyl phthalyl methyl glycolate, ethyl phthalyl propyl glycolate, methyl phthalyl butyl glycolate, ethyl phthalyl butyl glycolate, butyl phthalyl methyl glycolate, butyl phthalyl ethyl glycolate, propyl phthalyl butyl glycol Butyl phthalyl propyl glycolate, methyl phthalyl octyl glycolate, ethyl phthalyl octyl glycolate, octyl phthalyl
- phthalate ester plasticizer examples include diethyl phthalate, dimethoxyethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, dioctyl phthalate, dicyclohexyl phthalate, and dicyclohexyl terephthalate.
- citrate plasticizer examples include acetyl trimethyl citrate, acetyl triethyl citrate, and acetyl tributyl citrate.
- fatty acid ester plasticizers examples include butyl oleate, methylacetyl ricinoleate, and dibutyl sebacate.
- phosphate ester plasticizer examples include triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, diphenyl biphenyl phosphate, trioctyl phosphate, tributyl phosphate, and the like.
- the polyvalent carboxylic acid ester compound is composed of an ester of a divalent or higher, preferably a divalent to 20valent polyvalent carboxylic acid and an alcohol.
- the aliphatic polyvalent carboxylic acid is preferably divalent to 20-valent, and in the case of an aromatic polyvalent carboxylic acid or alicyclic polyvalent carboxylic acid, it is preferably trivalent to 20-valent.
- the polyvalent carboxylic acid is represented by the following general formula (b).
- R 12 (COOH) m1 (OH) n1
- R 12 represents an (m1 + n1) -valent organic group
- m1 represents a positive integer of 2 or more
- n1 represents an integer of 0 or more
- a COOH group represents a carboxyl group
- an OH group represents an alcoholic or phenolic hydroxyl group.
- the molecular weight of the polyvalent carboxylic acid ester compound is not particularly limited, but is preferably in the range of 300 to 1000, and more preferably in the range of 350 to 750.
- the larger one is preferable in terms of improvement in retention, and the smaller one is preferable in terms of moisture permeability and compatibility with cellulose acetate.
- the alcohol used for the polyvalent carboxylic acid ester that can be used in the present invention may be one kind or a mixture of two or more kinds.
- Examples of particularly preferable polyvalent carboxylic acid ester compounds include, for example, triethyl citrate, tributyl citrate, acetyl triethyl citrate (ATEC), acetyl tributyl citrate (ATBC), benzoyl tributyl citrate, acetyl triphenyl citrate, Acetyl tribenzyl citrate, dibutyl tartrate, diacetyl dibutyl tartrate, tributyl trimellitic acid, tetrabutyl pyromellitic acid and the like can be mentioned.
- the plasticizer can be appropriately used in the range of 1 to 40% by mass of the cellulose ester film.
- the cellulose ester film of the present invention can also contain an ultraviolet absorber.
- the ultraviolet absorber is intended to improve durability by absorbing ultraviolet light having a wavelength of 400 nm or less, and the transmittance at a wavelength of 370 nm is particularly preferably 10% or less, more preferably 5% or less. Preferably it is 2% or less.
- the amount of the UV absorber used is not uniform depending on the type of UV absorber, the operating conditions, etc., but when the dry film thickness of the polarizing plate protective film is 30 to 200 ⁇ m, the amount used is 0.5 to the polarizing plate protective film. Is preferably 10 to 10% by mass, and more preferably 0.6 to 4% by mass.
- Antioxidant are also referred to as deterioration inhibitors.
- a liquid crystal image display device or the like When a liquid crystal image display device or the like is placed in a high humidity and high temperature state, the cellulose acetate film may be deteriorated.
- the antioxidant has a role of delaying or preventing the cellulose acetate film from being decomposed by, for example, the residual solvent amount of halogen in the cellulose acetate film or phosphoric acid of the phosphoric acid plasticizer. It is preferable to make it contain in a 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- A phosphorus processing stabilizer such as t-butylphenyl) phosphite may be used in combination.
- the amount of these compounds added is preferably 1 ppm to 1.0%, more preferably 10 to 1000 ppm in terms of mass ratio with respect to the cellulose derivative.
- the cellulose ester film of the present invention has, for example, silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, kaolin, talc, calcined calcium silicate, hydrated calcium silicate, aluminum silicate in order to improve handleability. Further, it is preferable to contain inorganic fine particles such as magnesium silicate and calcium phosphate and a matting agent such as a crosslinked polymer. Of these, silicon dioxide is preferable because it can reduce the haze of the film.
- the primary average particle diameter of the fine particles is preferably 20 nm or less, more preferably 5 to 16 nm, and particularly preferably 5 to 12 nm.
- the amount added can be appropriately determined.
- the cellulose ester film of the present invention can be preferably used regardless of whether it is a film produced by a solution casting method or a film produced by a melt casting method.
- Production of the cellulose ester film of the present invention by the solution casting method is a step of preparing a dope by dissolving cellulose ester and additives in a solvent, a step of casting the dope on an endless metal support that moves infinitely It is performed by a step of drying the cast dope as a web, a step of peeling from the metal support, a step of stretching or maintaining the width, a step of further drying, and a step of winding up the finished film.
- the concentration of cellulose ester in the dope is preferably higher because the drying load after casting on the metal support can be reduced. However, if the concentration of cellulose ester is too high, the load during filtration increases and the filtration accuracy is poor. Become.
- the concentration that achieves both of these is preferably 10 to 35% by mass, and more preferably 15 to 25% by mass.
- the solvent used in the dope may be used alone or in combination of two or more, but it is preferable to use a mixture of a good solvent and a poor solvent of cellulose ester in terms of production efficiency, and there are many good solvents. This is preferable from the viewpoint of the solubility of the cellulose ester.
- a preferable range of the mixing ratio of the good solvent and the poor solvent is 70 to 98% by mass for the good solvent and 2 to 30% by mass for the poor solvent.
- the good solvent and the poor solvent change depending on the average acetylation degree (acetyl group substitution degree) of the cellulose ester.
- the good solvent used in the present invention is not particularly limited, and examples thereof include organic halogen compounds such as methylene chloride, dioxolanes, acetone, methyl acetate, and methyl acetoacetate. Particularly preferred is methylene chloride or methyl acetate.
- the poor solvent used in the present invention is not particularly limited, but for example, methanol, ethanol, n-butanol, cyclohexane, cyclohexanone and the like are preferably used.
- the dope preferably contains 0.01 to 2% by mass of water.
- the solvent used for dissolving the cellulose ester is used by collecting the solvent removed from the film by drying in the film-forming process and reusing it.
- the recovery solvent may contain trace amounts of additives added to the cellulose ester, such as plasticizers, UV absorbers, polymers, monomer components, etc., but even if these are included, they are preferably reused. Can be purified and reused if necessary.
- additives added to the cellulose ester such as plasticizers, UV absorbers, polymers, monomer components, etc., but even if these are included, they are preferably reused. Can be purified and reused if necessary.
- a general method can be used. When heating and pressurization are combined, it is possible to heat above the boiling point at normal pressure.
- a method in which a cellulose ester is mixed with a poor solvent and wetted or swollen, and then a good solvent is added and dissolved is also preferably used.
- Pressurization may be performed by a method of injecting an inert gas such as nitrogen gas or a method of increasing the vapor pressure of the solvent by heating. Heating is preferably performed from the outside.
- a jacket type is preferable because temperature control is easy.
- the heating temperature with the addition of the solvent is preferably higher from the viewpoint of the solubility of the cellulose ester, but if the heating temperature is too high, the required pressure increases and the productivity deteriorates.
- the preferred heating temperature is 45 to 120 ° C, more preferably 60 to 110 ° C, and still more preferably 70 ° C to 105 ° C.
- the pressure is adjusted so that the solvent does not boil at the set temperature.
- a cooling dissolution method is also preferably used, whereby the cellulose ester can be dissolved in a solvent such as methyl acetate.
- the cellulose ester solution is filtered using an appropriate filter medium such as filter paper.
- an appropriate filter medium such as filter paper.
- the filter medium it is preferable that the absolute filtration accuracy is small in order to remove insoluble matters and the like, but there is a problem that the filter medium is likely to be clogged if the absolute filtration accuracy is too small.
- a filter medium with an absolute filtration accuracy of 0.008 mm or less is preferable, a filter medium with 0.001 to 0.008 mm is more preferable, and a filter medium with 0.003 to 0.006 mm is still more preferable.
- the material of the filter medium there are no particular restrictions on the material of the filter medium, and ordinary filter media can be used. However, plastic filter media such as polypropylene and Teflon (registered trademark), and metal filter media such as stainless steel do not drop off fibers. preferable.
- Bright spot foreign matter means that when two polarizing plates are placed in a crossed Nicol state, an optical film or the like is placed between them, light is applied from one polarizing plate side, and observation is performed from the other polarizing plate side. It is a point (foreign matter) where light from the opposite side appears to leak, and the number of bright spots having a diameter of 0.01 mm or more is preferably 200 / cm 2 or less.
- it is 100 pieces / cm 2 or less, still more preferably 50 pieces / m 2 or less, still more preferably 0 to 10 pieces / cm 2 . Further, it is preferable that the number of bright spots of 0.01 mm or less is small.
- the dope can be filtered by a normal method, but the method of filtering while heating at a temperature not lower than the boiling point of the solvent at normal pressure and in a range where the solvent does not boil under pressure is the filtration pressure before and after filtration.
- the increase in the difference (referred to as differential pressure) is small and preferable.
- the preferred temperature is 45 to 120 ° C, more preferably 45 to 70 ° C, and still more preferably 45 to 55 ° C.
- the filtration pressure is preferably 1.6 MPa or less, more preferably 1.2 MPa or less, and further preferably 1.0 MPa or less.
- the metal support in the casting process is preferably a mirror-finished surface, and a stainless steel belt or a drum whose surface is plated with a casting is preferably used as the metal support.
- the cast width can be 1 ⁇ 4m.
- the surface temperature of the metal support in the casting step is ⁇ 50 ° C. to less than the boiling point of the solvent, and a higher temperature is preferable because the web drying speed can be increased. May deteriorate.
- the preferred support temperature is 0 to 55 ° C, more preferably 25 to 50 ° C.
- the method for controlling the temperature of the metal support is not particularly limited, but there are a method of blowing hot air or cold air, and a method of contacting hot water with the back side of the metal support. It is preferable to use warm water because heat transfer is performed efficiently, so that the time until the temperature of the metal support becomes constant is short. When warm air is used, wind at a temperature higher than the target temperature may be used.
- the amount of residual solvent when peeling the web from the metal support is preferably 10 to 150% by mass, more preferably 20 to 40% by mass or 60 to 130% by mass. Particularly preferred is 20 to 30% by mass or 70 to 120% by mass.
- the amount of residual solvent is defined by the following formula.
- Residual solvent amount (% by mass) ⁇ (MN) / N ⁇ ⁇ 100 M is the mass of a sample collected during or after the production of the web or film, and N is the mass after heating M at 115 ° C. for 1 hour.
- the web is peeled off from the metal support, and further dried, and the residual solvent amount is preferably 1% by mass or less, more preferably 0.1% by mass or less, Particularly preferred is 0 to 0.01% by mass or less.
- a roll drying method (a method in which webs are alternately passed through a plurality of rolls arranged above and below) and a method in which the web is dried while being conveyed by a tenter method are employed.
- the cellulose ester film of the present invention it is particularly preferable to perform stretching in the width direction (lateral direction) by a tenter method in which both ends of the web are held with clips or the like. Peeling is preferably performed at a peeling tension of 300 N / m or less.
- the means for drying the web is not particularly limited, and can be generally performed with hot air, infrared rays, a heating roll, microwave, or the like, but is preferably performed with hot air in terms of simplicity.
- drying temperature in the web drying process is increased stepwise from 40 to 200 ° C.
- the film thickness of the cellulose ester film is not particularly limited, but 10 to 200 ⁇ m is used.
- the film thickness is particularly preferably 10 to 100 ⁇ m. More preferably, it is 20 to 60 ⁇ m.
- the cellulose ester film of the present invention has a width of 1 to 4 m. Particularly, those having a width of 1.4 to 4 m are preferably used, and particularly preferably 1.6 to 3 m. If it exceeds 4 m, conveyance becomes difficult.
- the cellulose ester film has the structure of the present invention, and the refractive index is controlled by controlling the transport tension and stretching.
- the retardation value can be changed by lowering or increasing the tension in the longitudinal direction.
- the film can be biaxially or uniaxially stretched sequentially or simultaneously in the longitudinal direction (film forming direction) of the film and the direction orthogonal to the longitudinal direction of the film, that is, the width direction.
- the draw ratios in the biaxial directions perpendicular to each other are preferably in the range of 0.8 to 1.5 times in the casting direction and 1.1 to 2.5 times in the width direction, respectively. It is preferable to carry out in the range of 0.8 to 1.0 times in the direction and 1.2 to 2.0 times in the width direction.
- the stretching temperature is preferably 120 ° C. to 200 ° C., more preferably 150 ° C. to 200 ° C., more preferably more than 150 ° C. and 190 ° C. or less.
- the residual solvent in the film is preferably 20 to 0%, more preferably 15 to 0%.
- the residual solvent is stretched by 11% at 155 ° C., or the residual solvent is stretched by 2% at 155 ° C. Alternatively, it is preferable that the residual solvent is stretched at 11% at 160 ° C, or the residual solvent is stretched at less than 1% at 160 ° C.
- the method of stretching the web For example, a method in which a difference in peripheral speed is applied to a plurality of rolls, and the roll peripheral speed difference is used to stretch in the longitudinal direction, the both ends of the web are fixed with clips and pins, and the interval between the clips and pins is increased in the traveling direction. And a method of stretching in the vertical direction, a method of stretching in the horizontal direction and stretching in the horizontal direction, a method of stretching in the vertical and horizontal directions and stretching in both the vertical and horizontal directions, and the like. Of course, these methods may be used in combination.
- a tenter it may be a pin tenter or a clip tenter.
- the slow axis or the fast axis of the cellulose ester film of the present invention exists in the film plane, and ⁇ 1 is preferably ⁇ 1 ° or more and + 1 ° or less, assuming that the angle formed with the film forming direction is ⁇ 1. More preferably, it is 5 ° or more and + 0.5 ° or less.
- This ⁇ 1 can be defined as an orientation angle, and the measurement of ⁇ 1 can be performed using an automatic birefringence meter KOBRA-21ADH (Oji Scientific Instruments).
- ⁇ 1 satisfying the above relationship can contribute to obtaining high luminance in a display image, suppressing or preventing light leakage, and contributing to obtaining faithful color reproduction in a color liquid crystal display device.
- ⁇ Physical properties of cellulose ester film> The moisture permeability of the cellulose ester film of the present invention is preferably 300 to 1800 g / m 2 ⁇ 24 h at 40 ° C. and 90% RH, more preferably 400 to 1500 g / m 2 ⁇ 24 h, and 40 to 1300 g / m 2 ⁇ 24 h. Particularly preferred.
- the moisture permeability can be measured according to the method described in JIS Z 0208.
- the cellulose ester film of the present invention has a breaking elongation of preferably 10 to 80%, more preferably 20 to 50%.
- the visible light transmittance of the cellulose ester film of the present invention is preferably 90% or more, and more preferably 93% or more.
- the haze of the cellulose ester film of the present invention is preferably less than 1%, particularly preferably 0 to 0.1%.
- the cellulose ester film of the present invention can be used for a polarizing plate and a liquid crystal display device using the polarizing plate.
- the polarizing plate of the present invention can be produced by a general method.
- the cellulose ester film of the present invention is preferably bonded to at least one surface of a polarizer produced by subjecting the polarizer side to alkali saponification treatment and immersion drawing in an iodine solution using a completely saponified polyvinyl alcohol aqueous solution.
- Examples of the polarizing plate protective film for T1 and T4 of the present invention include a commercially available cellulose ester film (for example, Konica Minoltack KC8UX, KC5UX, KC8UCR3, KC8UCR4, KC8UCR5, KC8UY, KC4UY, KC4UE, KC8UE, KC8UY-X, -RHA, KC8UXW-RHA-C, KC8UXW-RHA-NC, KC4UXW-RHA-NC, manufactured by Konica Minolta Opto Co., Ltd.) are also preferably used.
- a commercially available cellulose ester film for example, Konica Minoltack KC8UX, KC5UX, KC8UCR3, KC8UCR4, KC8UCR5, KC8UY, KC4UY, KC4UE, KC8UE, KC8UY-X, -RHA, KC
- the polarizing plate used on the surface side of the display device preferably has an antireflection layer, an antistatic layer, an antifouling layer, and a backcoat layer in addition to the antiglare layer or the clear hard coat layer.
- a polarizer which is a main component of a polarizing plate, is an element that allows only light of a plane of polarization in a certain direction to pass.
- a typical polarizer currently known is a polyvinyl alcohol-based polarizing film, which is polyvinyl alcohol.
- iodine is dyed on a system film and one in which dichroic dye is dyed.
- the polarizer is formed by forming a polyvinyl alcohol aqueous solution into a film and dyeing the film by uniaxial stretching or dyeing or uniaxially stretching, and then performing a durability treatment with a boron compound.
- the film thickness of the polarizer is preferably 5 to 30 ⁇ m, particularly preferably 10 to 20 ⁇ m.
- the ethylene unit content described in JP-A-2003-248123, JP-A-2003-342322, etc. is 1 to 4 mol%
- the degree of polymerization is 2000 to 4000
- the degree of saponification is 99.0 to 99.99 mol%.
- Ethylene-modified polyvinyl alcohol is also preferably used.
- an ethylene-modified polyvinyl alcohol film having a hot water cutting temperature of 66 to 73 ° C. is preferably used.
- the difference in hot water cutting temperature between two points 5 cm away in the TD direction of the film is more preferably 1 ° C. or less in order to reduce color spots, and two points separated 1 cm in the TD direction of the film. In order to reduce color spots, it is more preferable that the difference in the hot water cutting temperature is 0.5 ° C. or less.
- a polarizer using this ethylene-modified polyvinyl alcohol film is excellent in polarization performance and durability performance and has few color spots, and is particularly preferably used for a large liquid crystal display device.
- the polarizer obtained as described above is usually used as a polarizing plate with a protective film bonded to both sides or one side thereof.
- the adhesive used for pasting include a PVA-based adhesive and a urethane-based adhesive. Among them, a PVA-based adhesive is preferably used.
- the polarizing plate of the present invention preferably uses a polarizing plate protective film.
- the LED called the pseudo-white type has two peaks around 480 nm (blue) and 570 nm (yellow), and the LED called the high color rendering white type has 530 nm (green) and 620 nm (red) in addition to blue. 3 peaks are observed. However, since the wavelength characteristics are different from those of the cold cathode tube, white reproduction is different.
- the effect becomes remarkable when it is a vertical alignment ECB type liquid crystal display device described in JP-A-2009-301010. This is because the liquid crystal display device has a high aperture ratio of 65% or more, so that the red color change of the polarizing plate can be clearly seen.
- Example 1 ⁇ Production of Cellulose Ester Film 101> ⁇ Fine particle dispersion 1> Fine particles (Aerosil R972V manufactured by Nippon Aerosil Co., Ltd.) 11 parts by mass Ethanol 89 parts by mass The above was stirred and mixed with a dissolver for 50 minutes, and then dispersed with Manton Gorin.
- Fine particle addition liquid 1 The fine particle dispersion 1 was slowly added to the dissolution tank containing methylene chloride with sufficient stirring. Further, the particles were dispersed by an attritor so that the secondary particles had a predetermined particle size. This was filtered through Finemet NF manufactured by Nippon Seisen Co., Ltd. to prepare a fine particle additive solution 1.
- a main dope solution having the following composition was prepared. First, methylene chloride and ethanol were added to the pressure dissolution tank. Cellulose acetate C was charged into a pressure dissolution tank containing a solvent while stirring. This is completely dissolved with heating and stirring. This was designated as Azumi Filter Paper No. The main dope solution was prepared by filtration using 244.
- the above was put into a closed container and dissolved while stirring to prepare a dope solution.
- the dope solution was uniformly cast on a stainless steel belt support at a temperature of 33 ° C. and a width of 1500 mm. The temperature of the stainless steel belt was controlled at 30 ° C.
- the solvent was evaporated until the amount of residual solvent in the cast (cast) film reached 75%, and then peeled off from the stainless steel belt support with a peeling tension of 130 N / m.
- the peeled cellulose acetate film was stretched 36% in the width direction using a tenter while applying heat at 160 ° C.
- the residual solvent at the start of stretching was 15%.
- aqueous solution consisting of 0.075 g of iodine, 5 g of potassium iodide, and 100 g of water, and then 3 g of potassium iodide and 7. It was immersed in a 45 ° C. aqueous solution consisting of 5 g and 100 g of water and uniaxially stretched (temperature 55 ° C., stretch ratio 5 times). This was washed with water and dried to obtain a polarizer.
- a polarizer, the cellulose acetate film, and Konica Minolta Tack KC4UY (a cellulose triacetate film manufactured by Konica Minolta Opto Co., Ltd., acetyl group substitution degree 2.90) are bonded to the back side in accordance with the following steps 1 to 5.
- a plate was made.
- Step 1 Soaked in a 2 mol / L sodium hydroxide solution at 60 ° C. for 90 seconds, then washed with water and dried to obtain a saponified cellulose acetate film on the side to be bonded to the polarizer.
- Step 2 The polarizer 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 polarizer in Step 2 was gently wiped off and placed on the cellulose ester film treated in Step 1.
- Step 4 The cellulose ester film, the polarizer and the back side cellulose ester film laminated in Step 3 were bonded at a pressure of 20 to 30 N / cm 2 and a conveying speed of about 2 m / min.
- Step 5 A sample obtained by bonding the polarizer, the cellulose ester film, and Konica Minoltack KC4UY prepared in Step 4 in a dryer at 80 ° C. is dried for 2 minutes, and a polarizing plate corresponding to the cellulose ester film is prepared. did.
- COP means ZEONOR film ZF14-060 manufactured by Nippon Zeon Co., Ltd., and bonding with a polarizer was subjected to corona discharge treatment, and thereafter a polarizing plate was produced in the same manner.
- the above-described LED backlight unit of the liquid crystal display is diverted to a liquid crystal display device using a liquid crystal cell (opening ratio: 67%) described in FIG. 18 of JP2009-301010A to produce a liquid crystal display device.
- a polarizing plate was bonded to the substrate.
- the liquid crystal display device was conditioned at 23 ° C. and 55% RH for 24 hours, and then a white image was displayed.
- the front color was visually observed and the transmission spectrum was observed (CS2000 manufactured by Konica Minolta Sensing Co., Ltd.).
- CS2000 manufactured by Konica Minolta Sensing Co., Ltd.
- the visual tint on the front of the bonded polarizing plate was the same.
- no difference was observed in the transmission spectrum.
- the liquid crystal display device was placed at 23 ° C. and 95% RH for 48 hours. It was taken out and a white image was displayed, which was similarly observed in an atmosphere of 23 ° C. and 55% RH.
- the observation results are shown in Table 3.
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Abstract
Disclosed is a liquid crystal display device which utilizes an LED as a back light, and which is equipped with a group of optical films that do not cause reddish discoloration of a polarizing plate and do not cause the deterioration in quality of a display image. Specifically disclosed is a liquid crystal display device which comprises a viewing-side polarizing plate having a structure sandwiched by two polarizing plate protecting films, a liquid crystal cell, a back-light-side polarizing plate having a structure sandwiched by two polarizing plate protecting films, and an LED back light in this order from the viewing side, and which is characterized in that each of the two polarizing plate protecting films in the viewing-side polarizing plate is a cellulose ester film and a polarizing plate protecting film located on the liquid crystal cell side of the back-light-side polarizing plate is a cellulose ester film.
Description
本発明は、LEDバックライトを有する液晶表示装置に関する。
The present invention relates to a liquid crystal display device having an LED backlight.
液晶表示装置に用いられる偏光板は、通常、偏光能を有する偏光子の両面に、接着剤層を介して保護フィルムが貼り合わせられている。
In a polarizing plate used for a liquid crystal display device, a protective film is usually bonded to both surfaces of a polarizer having polarizing ability via an adhesive layer.
この偏光板は、従来から、偏光板が長期使用によって熱及び湿度に曝されると、偏光性能が変動し、さらにそれにより、液晶表示装置の表示性能が低下することが知られている。
Conventionally, it is known that the polarizing performance of the polarizing plate fluctuates when the polarizing plate is exposed to heat and humidity due to long-term use, and further, the display performance of the liquid crystal display device deteriorates.
この原因の一つとして、環境中の水分が偏光板中に浸入し、それにより偏光子が寸法変化することであると考えられ、従って、保護フィルムに低透湿性のポリマーフィルムを使用することが、偏光板の耐久性の改善に寄与すると考えられていた(特許文献1)。
One reason for this is thought to be that moisture in the environment permeates into the polarizing plate, thereby changing the size of the polarizer. Therefore, the use of a polymer film with low moisture permeability as the protective film is considered. It was thought that it contributed to the improvement of durability of a polarizing plate (patent document 1).
一方、液晶表示装置の使用形態も様々となり、高温・高湿度の環境のみならず、低温・高湿度の環境等、様々な環境における耐久性が求められているが、その対策は、ほとんどが高温・高湿度環境下での偏光板の耐久性の改善であったため、他の環境における耐久性を損なう場合があることがわかってきた。
On the other hand, liquid crystal display devices are used in various ways, and durability is required not only in high-temperature and high-humidity environments, but also in low-temperature and high-humidity environments. -It has been found that the durability of the polarizing plate in a high-humidity environment is improved, so that the durability in other environments may be impaired.
例えば、20℃程度の比較的低温でかつ高湿度の環境下で偏光板を長期使用すると、赤色の変色が生じることがあり、これは、偏光子の両面に低透湿性のポリマーフィルムを有する偏光板を使用する場合により顕著になることが判明した(特許文献2)。
For example, when a polarizing plate is used for a long time in a relatively low temperature and high humidity environment of about 20 ° C., red discoloration may occur. This is a polarization having a low moisture permeability polymer film on both sides of the polarizer. It became clear that it became more remarkable when using a board (patent document 2).
しかしながら、この変色は、両面に低透湿性のポリマーフィルムを使用しなければほとんど実用的に問題となるレベルではなかったために、これまでは既存の偏光板保護フィルムの設計によって対応していた。
However, this discoloration has not been at a practically problematic level unless a low moisture-permeable polymer film is used on both sides, and so far, it has been dealt with by the design of an existing polarizing plate protective film.
しかしながら、バックライトにLEDを使用しさらに開口率を高めた最新の液晶表示装置では、それが非常に目立つようになり、問題レベルとなってきた。
However, in the latest liquid crystal display device using an LED for the backlight and further increasing the aperture ratio, it has become very noticeable and has become a problem level.
従来の冷陰極管とLEDの可視領域(白)での光源スペクトルの相違が、根本の原因にあるものと推定される。
The difference in the light source spectrum between the conventional cold cathode fluorescent lamp and the LED in the visible region (white) is presumed to be the root cause.
本発明の目的は、LEDをバックライトとして使用する液晶表示装置において、偏光板に赤み変色を発生させず、表示画像品質を劣化させない光学フィルム群を有する液晶表示装置を提供することにある。
An object of the present invention is to provide a liquid crystal display device having an optical film group that does not cause reddish discoloration in a polarizing plate and does not deteriorate display image quality in a liquid crystal display device using an LED as a backlight.
本発明の上記目的は、下記によって達成された。
The above object of the present invention has been achieved by the following.
1.2枚の偏光板保護フィルムで挟まれた構造を有する視認側偏光板、液晶セル、2枚の偏光板保護フィルムで挟まれた構造を有するバックライト側偏光板、およびLEDバックライトを、視認側からこの順で有する液晶表示装置において、該視認側偏光板の2枚の偏光板保護フィルムがいずれもセルロースエステルフィルムであり、かつ該バックライト側偏光板の液晶セル側の偏光板保護フィルムがセルロースエステルフィルムであることを特徴とする液晶表示装置。
1. A viewing side polarizing plate having a structure sandwiched between two polarizing plate protective films, a liquid crystal cell, a backlight side polarizing plate having a structure sandwiched between two polarizing plate protective films, and an LED backlight, In the liquid crystal display device in this order from the viewing side, the two polarizing plate protective films of the viewing side polarizing plate are both cellulose ester films, and the polarizing plate protective film on the liquid crystal cell side of the backlight side polarizing plate Is a cellulose ester film.
2.前記視認側偏光板であって液晶セル側の偏光板保護フィルムが、アセチル基置換度Xが2.10≦X<2.50のセルロースアセテートフィルムであることを特徴とする前記1記載の液晶表示装置。
2. 2. The liquid crystal display according to 1 above, wherein the polarizing plate protective film on the viewing side polarizing plate is a cellulose acetate film having an acetyl group substitution degree X of 2.10 ≦ X <2.50. apparatus.
3.前記液晶表示装置の開口率が、65%以上であることを特徴とする前記1または2記載の液晶表示装置。
3. 3. The liquid crystal display device according to 1 or 2, wherein an aperture ratio of the liquid crystal display device is 65% or more.
本発明の構成によって、LEDをバックライトとして使用する液晶表示装置において、偏光板に赤み変色を発生させず、表示画像品質を劣化させない液晶表示装置を得ることができる。
According to the configuration of the present invention, in a liquid crystal display device using an LED as a backlight, it is possible to obtain a liquid crystal display device that does not cause reddish discoloration in the polarizing plate and does not deteriorate display image quality.
<本発明の液晶表示装置>
本発明の液晶表示装置は、2枚の偏光板保護フィルムで挟まれた構造を有する視認側偏光板、液晶セル、2枚の偏光板保護フィルムで挟まれた構造を有するバックライト側偏光板、およびLEDバックライトを、視認側からこの順で有する液晶表示装置において、該視認側偏光板の2枚の偏光板保護フィルムがいずれもセルロースエステルフィルムであり、かつ該バックライト側偏光板の液晶セル側の偏光板保護フィルムがセルロースエステルフィルムであることを特徴とする。 <Liquid Crystal Display Device of the Present Invention>
The liquid crystal display device of the present invention is a viewing side polarizing plate having a structure sandwiched between two polarizing plate protective films, a liquid crystal cell, a backlight side polarizing plate having a structure sandwiched between two polarizing plate protective films, And the LED backlight in this order from the viewing side, the two polarizing plate protective films of the viewing side polarizing plate are both cellulose ester films, and the liquid crystal cell of the backlight side polarizing plate The polarizing plate protective film on the side is a cellulose ester film.
本発明の液晶表示装置は、2枚の偏光板保護フィルムで挟まれた構造を有する視認側偏光板、液晶セル、2枚の偏光板保護フィルムで挟まれた構造を有するバックライト側偏光板、およびLEDバックライトを、視認側からこの順で有する液晶表示装置において、該視認側偏光板の2枚の偏光板保護フィルムがいずれもセルロースエステルフィルムであり、かつ該バックライト側偏光板の液晶セル側の偏光板保護フィルムがセルロースエステルフィルムであることを特徴とする。 <Liquid Crystal Display Device of the Present Invention>
The liquid crystal display device of the present invention is a viewing side polarizing plate having a structure sandwiched between two polarizing plate protective films, a liquid crystal cell, a backlight side polarizing plate having a structure sandwiched between two polarizing plate protective films, And the LED backlight in this order from the viewing side, the two polarizing plate protective films of the viewing side polarizing plate are both cellulose ester films, and the liquid crystal cell of the backlight side polarizing plate The polarizing plate protective film on the side is a cellulose ester film.
図1は、本発明の基本的な液晶表示装置の概略図である。本発明の液晶表示装置では、バックライトがLEDであり、その場合に偏光板保護フィルムT1(視認側偏光板の視認側偏光板保護フィルム)、T2(視認側偏光板の液晶セル側偏光板保護フィルム)、T3(バックライト側偏光板の液晶セル側偏光板保護フィルム)がセルロースエステルフィルムであることを特徴とする。特に、T2のアセチル基置換度Xが2.1≦X<2.5のセルロースアセテートフィルムであることが好ましい。そして、本発明の効果は、液晶表示装置の開口率が65%以上である場合に顕著である。
<セルロースエステルフィルム>
本発明のT1~T3のセルロースエステルフィルムの主成分としては、セルローストリアセテート、セルロースジアセテート、セルロースアセテートブチレート、セルロースアセテートプロピオネートが好ましく、中でもセルロースジアセテートが好ましく用いられる。 FIG. 1 is a schematic view of a basic liquid crystal display device of the present invention. In the liquid crystal display device of the present invention, the backlight is an LED, and in that case, a polarizing plate protective film T1 (viewing side polarizing plate protective film of the viewing side polarizing plate) and T2 (liquid crystal cell side polarizing plate protection of the viewing side polarizing plate). Film) and T3 (liquid crystal cell side polarizing plate protective film of the backlight side polarizing plate) are cellulose ester films. In particular, a cellulose acetate film having an acetyl group substitution degree X of T2 of 2.1 ≦ X <2.5 is preferable. And the effect of this invention is remarkable when the aperture ratio of a liquid crystal display device is 65% or more.
<Cellulose ester film>
As the main component of the cellulose ester film of T1 to T3 of the present invention, cellulose triacetate, cellulose diacetate, cellulose acetate butyrate, and cellulose acetate propionate are preferable, and among these, cellulose diacetate is preferably used.
<セルロースエステルフィルム>
本発明のT1~T3のセルロースエステルフィルムの主成分としては、セルローストリアセテート、セルロースジアセテート、セルロースアセテートブチレート、セルロースアセテートプロピオネートが好ましく、中でもセルロースジアセテートが好ましく用いられる。 FIG. 1 is a schematic view of a basic liquid crystal display device of the present invention. In the liquid crystal display device of the present invention, the backlight is an LED, and in that case, a polarizing plate protective film T1 (viewing side polarizing plate protective film of the viewing side polarizing plate) and T2 (liquid crystal cell side polarizing plate protection of the viewing side polarizing plate). Film) and T3 (liquid crystal cell side polarizing plate protective film of the backlight side polarizing plate) are cellulose ester films. In particular, a cellulose acetate film having an acetyl group substitution degree X of T2 of 2.1 ≦ X <2.5 is preferable. And the effect of this invention is remarkable when the aperture ratio of a liquid crystal display device is 65% or more.
<Cellulose ester film>
As the main component of the cellulose ester film of T1 to T3 of the present invention, cellulose triacetate, cellulose diacetate, cellulose acetate butyrate, and cellulose acetate propionate are preferable, and among these, cellulose diacetate is preferably used.
本発明のT1のセルロースエステルフィルムは、特に偏光板保護フィルムに求められる光学等方性の観点から、アセチル基の置換度をX、その他のアシル基の置換度をYとした時、X、Yが下記式の範囲にあるセルロースエステルをフィルム構成成分の50質量%以上であるフィルムが用いられる。
The cellulose ester film of T1 of the present invention is X, Y when the substitution degree of acetyl groups is X and the substitution degree of other acyl groups is Y, particularly from the viewpoint of optical isotropy required for a polarizing plate protective film. Is a film in which the cellulose ester in the range of the following formula is 50% by mass or more of the film constituents.
式 2.5≦X+Y≦3.0
特に、セルローストリアセテートフィルムであることが好ましい。本発明の機能を損なわない範囲で別の樹脂が混合されていてもよく、目的に応じて各種添加剤を加えても良い。 Formula 2.5 ≦ X + Y ≦ 3.0
In particular, a cellulose triacetate film is preferable. Another resin may be mixed as long as the function of the present invention is not impaired, and various additives may be added according to the purpose.
特に、セルローストリアセテートフィルムであることが好ましい。本発明の機能を損なわない範囲で別の樹脂が混合されていてもよく、目的に応じて各種添加剤を加えても良い。 Formula 2.5 ≦ X + Y ≦ 3.0
In particular, a cellulose triacetate film is preferable. Another resin may be mixed as long as the function of the present invention is not impaired, and various additives may be added according to the purpose.
T1としては、通常の偏光板保護フィルムと使用している市販のセルローストリアセテートフィルムを使用することができる。
As T1, a commercially available cellulose triacetate film used with a normal polarizing plate protective film can be used.
本発明のT2、T3のセルロースエステルフィルムとしては、位相差発現性が高く、高い位相差を有する位相差フィルムとする場合であっても薄膜化可能であること、位相差を発現させるための延伸倍率を低く抑えることができる観点から、下記式の範囲を満たすセルロースエステルからなるフィルムが用いられる。
The cellulose ester film of T2 and T3 of the present invention has high retardation development and can be made into a thin film even when it is a retardation film having a high retardation, stretching for expressing the retardation. From the viewpoint of keeping the magnification low, a film made of cellulose ester that satisfies the range of the following formula is used.
式 2.1≦X+Y<2.5
置換されていない部分は水酸基として存在している。 Formula 2.1 ≦ X + Y <2.5
The non-substituted part exists as a hydroxyl group.
置換されていない部分は水酸基として存在している。 Formula 2.1 ≦ X + Y <2.5
The non-substituted part exists as a hydroxyl group.
本発明のT2、T3のセルロースエステルフィルムにおいて、T2が2.1≦X<2.5であるセルロースアセテートフィルムであることが好ましく、さらにT2およびT3が同時に2.1≦X<2.5であるセルロースジアセテートフィルムであることが最も好ましい。
The cellulose ester film of T2 and T3 of the present invention is preferably a cellulose acetate film in which T2 is 2.1 ≦ X <2.5, and T2 and T3 are simultaneously 2.1 ≦ X <2.5. Most preferred is a cellulose diacetate film.
本発明のT2、T3であるセルロースアセテートフィルムは、求められる光学補償効果によって必要とされる位相差を適宜調整することができ、高い位相差発現性を生かす観点から、面内方向におけるレターデーションRoが30nm以上であることが好ましく、30~200nmの範囲であることがより好ましく、厚み方向のレターデーションRthは70nm以上であることが好ましく、70~300nmの範囲であることがより好ましい。
The cellulose acetate films T2 and T3 of the present invention can appropriately adjust the retardation required for the required optical compensation effect, and from the viewpoint of taking advantage of high retardation development, retardation Ro in the in-plane direction. Is preferably 30 nm or more, more preferably in the range of 30 to 200 nm, and the retardation Rth in the thickness direction is preferably 70 nm or more, and more preferably in the range of 70 to 300 nm.
位相差の調整方法としては、特に制限はないが、延伸処理によって調整する方法が一般的である。詳しい調整方法について後述する。
The method of adjusting the phase difference is not particularly limited, but a method of adjusting by stretching is common. A detailed adjustment method will be described later.
これら本発明の偏光板保護フィルム及び位相差フィルムに用いられるセルロースアセテートは公知の方法で合成することができる。
These cellulose acetates used for the polarizing plate protective film and the retardation film of the present invention can be synthesized by a known method.
本発明の位相差フィルム及び偏光板保護フィルムで用いられる、セルロースアセテートの原料のセルロースとしては、特に限定はないが、綿花リンター、木材パルプ(針葉樹由来、広葉樹由来)、ケナフ等を挙げることが出来る。またそれらから得られたセルロースアセテートはそれぞれ任意の割合で混合使用することが出来る。
The cellulose used as a raw material of cellulose acetate used in the retardation film and polarizing plate protective film of the present invention is not particularly limited, and examples thereof include cotton linters, wood pulp (derived from coniferous trees, derived from hardwoods), kenaf and the like. . Moreover, the cellulose acetate obtained from them can be mixed and used in arbitrary ratios, respectively.
本発明のセルロースアセテートは、公知の方法により製造することができる。具体的には特開平10-45804号に記載の方法を参考にして合成することができる。
The cellulose acetate of the present invention can be produced by a known method. Specifically, it can be synthesized with reference to the method described in JP-A-10-45804.
市販品としては、ダイセル社L20、L30、L40、L50、イーストマンケミカル社のCa398-3、Ca398-6、Ca398-10、Ca398-30、Ca394-60Sが挙げられる。
Commercially available products include Daicel L20, L30, L40, L50, and Eastman Chemical's Ca398-3, Ca398-6, Ca398-10, Ca398-30, and Ca394-60S.
(溶液粘度)
本発明に用いられるセルロースアセテートとしては、重量平均分子量/粘度の値が1.2~2.4であるものと、4.4~5.5であるものを混合して使用することが好ましい。重量平均分子量を高くすることで、フィルムの破断性を改良し、ドープ(溶媒に樹脂を溶かした溶解液を以後ドープと呼ぶ)とした場合の粘度を低くすることで固形分濃度を高くすることによりフィルムの生産性を向上させる。上記効果を組み合わせることにより、生産性が高く破断しないフィルムを製造できることを見出すことができた。 (Solution viscosity)
As the cellulose acetate used in the present invention, it is preferable to use a mixture of those having a weight average molecular weight / viscosity value of 1.2 to 2.4 and those of 4.4 to 5.5. Increasing the weight average molecular weight improves the film breakability and increases the solid content concentration by lowering the viscosity when a dope (a solution obtained by dissolving a resin in a solvent is hereinafter referred to as a dope). This improves film productivity. By combining the above effects, it was found that a film having high productivity and not breaking can be produced.
本発明に用いられるセルロースアセテートとしては、重量平均分子量/粘度の値が1.2~2.4であるものと、4.4~5.5であるものを混合して使用することが好ましい。重量平均分子量を高くすることで、フィルムの破断性を改良し、ドープ(溶媒に樹脂を溶かした溶解液を以後ドープと呼ぶ)とした場合の粘度を低くすることで固形分濃度を高くすることによりフィルムの生産性を向上させる。上記効果を組み合わせることにより、生産性が高く破断しないフィルムを製造できることを見出すことができた。 (Solution viscosity)
As the cellulose acetate used in the present invention, it is preferable to use a mixture of those having a weight average molecular weight / viscosity value of 1.2 to 2.4 and those of 4.4 to 5.5. Increasing the weight average molecular weight improves the film breakability and increases the solid content concentration by lowering the viscosity when a dope (a solution obtained by dissolving a resin in a solvent is hereinafter referred to as a dope). This improves film productivity. By combining the above effects, it was found that a film having high productivity and not breaking can be produced.
ドープの調液方法としては、0℃以上の温度(常温または高温)で調製する方法と低温で調製する冷却調液方法とが知られている。0℃以上の温度で調製する場合には有機溶媒としてハロゲン化炭化水素(特にメチレンクロリド)を用いることが好ましい。これらの調製方法及び有機溶媒については発明協会公開技法(公技番号2001-1745号、2001年3月15日発行、以下公開技法2001-1745号と略す)第12項から第15項に有機溶剤が記載されており、第22項から第25項に調製方法が記載されている。
As a dope preparation method, a method of preparing at a temperature of 0 ° C. or higher (normal temperature or high temperature) and a cooling preparation method of preparing at a low temperature are known. When preparing at a temperature of 0 ° C. or higher, it is preferable to use a halogenated hydrocarbon (particularly methylene chloride) as the organic solvent. Regarding these preparation methods and organic solvents, the Invention Association public technique (public technical number 2001-1745, published on March 15, 2001, hereinafter abbreviated as public technique 2001-1745), paragraphs 12 to 15 And the preparation method is described in the items 22 to 25.
本発明のセルロースアセテート溶液の粘度は、15から140Pa・sであり、かつ溶解、ろ過時のドープの温度が20℃以上30℃以下であることが好ましい。さらに好ましくは、低粘度のセルロースアセテート溶液の粘度が30から90Pa・sであることである。
The viscosity of the cellulose acetate solution of the present invention is preferably 15 to 140 Pa · s, and the temperature of the dope during dissolution and filtration is preferably 20 ° C. or higher and 30 ° C. or lower. More preferably, the viscosity of the low-viscosity cellulose acetate solution is 30 to 90 Pa · s.
本発明のセルロースアセテート溶液の粘度はJIS Z 8803に記載された方法に従い、B型粘度計 型式VS-A1(芝浦システム株式会社)を用いて25℃で測定することができる。
The viscosity of the cellulose acetate solution of the present invention can be measured at 25 ° C. using a B-type viscometer Model VS-A1 (Shibaura System Co., Ltd.) according to the method described in JIS Z 8803.
(分子量分布)
本発明のT1~T3のセルロースエステルフィルムの主成分であるセルロースエステルの平均分子量及び分子量分布は、高速液体クロマトグラフィーを用い測定できるので、これを用いて数平均分子量(Mn)、重量平均分子量(Mw)を算出し、その比を計算することができる。 (Molecular weight distribution)
Since the average molecular weight and molecular weight distribution of the cellulose ester which is the main component of the cellulose ester film of T1 to T3 of the present invention can be measured using high performance liquid chromatography, the number average molecular weight (Mn) and the weight average molecular weight ( Mw) and the ratio can be calculated.
本発明のT1~T3のセルロースエステルフィルムの主成分であるセルロースエステルの平均分子量及び分子量分布は、高速液体クロマトグラフィーを用い測定できるので、これを用いて数平均分子量(Mn)、重量平均分子量(Mw)を算出し、その比を計算することができる。 (Molecular weight distribution)
Since the average molecular weight and molecular weight distribution of the cellulose ester which is the main component of the cellulose ester film of T1 to T3 of the present invention can be measured using high performance liquid chromatography, the number average molecular weight (Mn) and the weight average molecular weight ( Mw) and the ratio can be calculated.
測定条件は以下の通りである。
溶媒:メチレンクロライド
カラム:Shodex K806,K805,K803G(昭和電工(株)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)製)
流量:1.0ml/min
校正曲線:標準ポリスチレンSTK standardポリスチレン(東ソー(株)製)Mw=1000000~500までの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。 The measurement conditions are as follows.
Solvent: Methylene chloride Column: Shodex K806, K805, K803G (Used by connecting three Showa Denko Co., Ltd.)
Column temperature: 25 ° C
Sample concentration: 0.1% by mass
Detector: RI Model 504 (GL Science Co., Ltd.)
Pump: L6000 (manufactured by Hitachi, Ltd.)
Flow rate: 1.0 ml / min
Calibration curve: Standard polystyrene STK standard polystyrene (manufactured by Tosoh Co., Ltd.) Mw = 1000,000 to 500 calibration curves with 13 samples were used. The 13 samples are preferably used at approximately equal intervals.
溶媒:メチレンクロライド
カラム:Shodex K806,K805,K803G(昭和電工(株)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)製)
流量:1.0ml/min
校正曲線:標準ポリスチレンSTK standardポリスチレン(東ソー(株)製)Mw=1000000~500までの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。 The measurement conditions are as follows.
Solvent: Methylene chloride Column: Shodex K806, K805, K803G (Used by connecting three Showa Denko Co., Ltd.)
Column temperature: 25 ° C
Sample concentration: 0.1% by mass
Detector: RI Model 504 (GL Science Co., Ltd.)
Pump: L6000 (manufactured by Hitachi, Ltd.)
Flow rate: 1.0 ml / min
Calibration curve: Standard polystyrene STK standard polystyrene (manufactured by Tosoh Co., Ltd.) Mw = 1000,000 to 500 calibration curves with 13 samples were used. The 13 samples are preferably used at approximately equal intervals.
セルロースエステルの分子量は重量平均分子量(Mw)で100,000~200,000のものが好ましく、130,000~160,000のものが更に好ましい。本発明で用いられるセルロースアセテートはMn/Mw比は1.0以上5.0未満が好ましく、より好ましくは2.5以上4.0未満である。
The molecular weight of the cellulose ester is preferably 100,000 to 200,000, more preferably 130,000 to 160,000 in terms of weight average molecular weight (Mw). The cellulose acetate used in the present invention preferably has a Mn / Mw ratio of 1.0 or more and less than 5.0, more preferably 2.5 or more and less than 4.0.
また、セルロースアセテートの重合度は、粘度平均重合度で200~800が好ましく、250~650がより好ましく、250~450が更に好ましく、250~400が特に好ましい。粘度平均重合度は宇田らの極限粘度法(宇田和夫、斉藤秀夫、繊維学会誌、第18巻第1号、105~120頁、1962年)に従い測定できる。粘度平均重合度の測定方法については、特開平9-95538号公報にも記載がある。
<添加剤>
本発明のセルロースエステルフィルムには、物性改良剤として一般式(1)で表される糖エステル化合物を含有させることが好ましい。 The degree of polymerization of cellulose acetate is preferably 200 to 800, more preferably 250 to 650, still more preferably 250 to 450, and particularly preferably 250 to 400 in terms of viscosity average degree of polymerization. The viscosity average degree of polymerization can be measured according to Uda et al.'S limiting viscosity method (Kazuo Uda, Hideo Saito, Journal of Textile Science, Vol. 18, No. 1, pp. 105-120, 1962). A method for measuring the viscosity average degree of polymerization is also described in JP-A-9-95538.
<Additives>
The cellulose ester film of the present invention preferably contains a sugar ester compound represented by the general formula (1) as a physical property improving agent.
<添加剤>
本発明のセルロースエステルフィルムには、物性改良剤として一般式(1)で表される糖エステル化合物を含有させることが好ましい。 The degree of polymerization of cellulose acetate is preferably 200 to 800, more preferably 250 to 650, still more preferably 250 to 450, and particularly preferably 250 to 400 in terms of viscosity average degree of polymerization. The viscosity average degree of polymerization can be measured according to Uda et al.'S limiting viscosity method (Kazuo Uda, Hideo Saito, Journal of Textile Science, Vol. 18, No. 1, pp. 105-120, 1962). A method for measuring the viscosity average degree of polymerization is also described in JP-A-9-95538.
<Additives>
The cellulose ester film of the present invention preferably contains a sugar ester compound represented by the general formula (1) as a physical property improving agent.
(式中、R1~R8は、置換又は無置換のアルキルカルボニル基、或いは、置換又は無置換のアリルカルボニル基を表し、R1~R8は、同じであっても、異なっていてもよい。)
本発明のセルロースエステルフィルムには、一般式(2)で表されるエステル化合物を可塑剤として含有することが好ましい。 (Wherein R 1 to R 8 represent a substituted or unsubstituted alkylcarbonyl group or a substituted or unsubstituted allylcarbonyl group, and R 1 to R 8 may be the same or different. Good.)
The cellulose ester film of the present invention preferably contains an ester compound represented by the general formula (2) as a plasticizer.
本発明のセルロースエステルフィルムには、一般式(2)で表されるエステル化合物を可塑剤として含有することが好ましい。 (Wherein R 1 to R 8 represent a substituted or unsubstituted alkylcarbonyl group or a substituted or unsubstituted allylcarbonyl group, and R 1 to R 8 may be the same or different. Good.)
The cellulose ester film of the present invention preferably contains an ester compound represented by the general formula (2) as a plasticizer.
一般式(2) B-(G-A)n-G-B
(式中、Bはヒドロキシ基またはカルボン酸残基、Gは炭素数2~12のアルキレングリコール残基または炭素数6~12のアリールグリコール残基または炭素数が4~12のオキシアルキレングリコール残基、Aは炭素数4~12のアルキレンジカルボン酸残基または炭素数6~12のアリールジカルボン酸残基を表す。nは1以上の整数を表す。)
一般式(2)において、炭素数2~12のアルキレングリコール成分としては、エチレングリコール、1,2-プロピレングリコール、1,3-プロピレングリコール、1,2-ブタンジオール、1,3-ブタンジオール、1,2-プロパンジオール、2-メチル1,3-プロパンジオール、1,4-ブタンジオール、1,5-ペンタンジオール、2,2-ジメチル-1,3-プロパンジオール(ネオペンチルグリコール)、2,2-ジエチル-1,3-プロパンジオール(3,3-ジメチロールペンタン)、2-n-ブチル-2-エチル-1,3プロパンジオール(3,3-ジメチロールヘプタン)、3-メチル-1,5-ペンタンジオール1,6-ヘキサンジオール、2,2,4-トリメチル1,3-ペンタンジオール、2-エチル1,3-ヘキサンジオール、2-メチル1,8-オクタンジオール、1,9-ノナンジオール、1,10-デカンジオール、1,12-オクタデカンジオール等があり、これらのグリコールは、1種または2種以上の混合物として使用される。 Formula (2) B- (GA) nGB
(Wherein B is a hydroxy group or carboxylic acid residue, G is an alkylene glycol residue having 2 to 12 carbon atoms, an aryl glycol residue having 6 to 12 carbon atoms, or an oxyalkylene glycol residue having 4 to 12 carbon atoms) A represents an alkylene dicarboxylic acid residue having 4 to 12 carbon atoms or an aryl dicarboxylic acid residue having 6 to 12 carbon atoms, and n represents an integer of 1 or more.)
In the general formula (2), the alkylene glycol component having 2 to 12 carbon atoms includes ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,2-propanediol, 2-methyl 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 2 , 2-diethyl-1,3-propanediol (3,3-dimethylolpentane), 2-n-butyl-2-ethyl-1,3-propanediol (3,3-dimethylolheptane), 3-methyl- 1,5-pentanediol 1,6-hexanediol, 2,2,4-trimethyl 1,3-pentanediol, 2-ethyl 1, -Hexanediol, 2-methyl 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-octadecanediol, and the like. Used as a mixture.
(式中、Bはヒドロキシ基またはカルボン酸残基、Gは炭素数2~12のアルキレングリコール残基または炭素数6~12のアリールグリコール残基または炭素数が4~12のオキシアルキレングリコール残基、Aは炭素数4~12のアルキレンジカルボン酸残基または炭素数6~12のアリールジカルボン酸残基を表す。nは1以上の整数を表す。)
一般式(2)において、炭素数2~12のアルキレングリコール成分としては、エチレングリコール、1,2-プロピレングリコール、1,3-プロピレングリコール、1,2-ブタンジオール、1,3-ブタンジオール、1,2-プロパンジオール、2-メチル1,3-プロパンジオール、1,4-ブタンジオール、1,5-ペンタンジオール、2,2-ジメチル-1,3-プロパンジオール(ネオペンチルグリコール)、2,2-ジエチル-1,3-プロパンジオール(3,3-ジメチロールペンタン)、2-n-ブチル-2-エチル-1,3プロパンジオール(3,3-ジメチロールヘプタン)、3-メチル-1,5-ペンタンジオール1,6-ヘキサンジオール、2,2,4-トリメチル1,3-ペンタンジオール、2-エチル1,3-ヘキサンジオール、2-メチル1,8-オクタンジオール、1,9-ノナンジオール、1,10-デカンジオール、1,12-オクタデカンジオール等があり、これらのグリコールは、1種または2種以上の混合物として使用される。 Formula (2) B- (GA) nGB
(Wherein B is a hydroxy group or carboxylic acid residue, G is an alkylene glycol residue having 2 to 12 carbon atoms, an aryl glycol residue having 6 to 12 carbon atoms, or an oxyalkylene glycol residue having 4 to 12 carbon atoms) A represents an alkylene dicarboxylic acid residue having 4 to 12 carbon atoms or an aryl dicarboxylic acid residue having 6 to 12 carbon atoms, and n represents an integer of 1 or more.)
In the general formula (2), the alkylene glycol component having 2 to 12 carbon atoms includes ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,2-propanediol, 2-
以下に、本発明の一般式(2)で表されるエステル化合物の具体的化合物を示す。
Hereinafter, specific compounds of the ester compound represented by the general formula (2) of the present invention are shown.
一般式(1)または(2)で表される化合物は、セルロースエステルフィルムの1~40質量%の範囲で適宜使用することができる。
The compound represented by the general formula (1) or (2) can be appropriately used in the range of 1 to 40% by mass of the cellulose ester film.
〈その他の添加剤〉
(その他の可塑剤)
本発明のセルロースアセテートフィルムは、本発明の効果を得る上で必要に応じて一般式(1)、(2)で表される化合物以外の可塑剤を含有することができる。 <Other additives>
(Other plasticizers)
The cellulose acetate film of the present invention can contain a plasticizer other than the compounds represented by the general formulas (1) and (2) as necessary for obtaining the effects of the present invention.
(その他の可塑剤)
本発明のセルロースアセテートフィルムは、本発明の効果を得る上で必要に応じて一般式(1)、(2)で表される化合物以外の可塑剤を含有することができる。 <Other additives>
(Other plasticizers)
The cellulose acetate film of the present invention can contain a plasticizer other than the compounds represented by the general formulas (1) and (2) as necessary for obtaining the effects of the present invention.
可塑剤は特に限定されないが、好ましくは、多価カルボン酸エステル系可塑剤、グリコレート系可塑剤、フタル酸エステル系可塑剤、脂肪酸エステル系可塑剤および多価アルコールエステル系可塑剤、エステル系可塑剤、アクリル系可塑剤等から選択される。
The plasticizer is not particularly limited, but is preferably a polycarboxylic acid ester plasticizer, a glycolate plasticizer, a phthalate ester plasticizer, a fatty acid ester plasticizer, a polyhydric alcohol ester plasticizer, or an ester plasticizer. Agent, acrylic plasticizer and the like.
そのうち、可塑剤を2種以上用いる場合は、少なくとも1種は多価アルコールエステル系可塑剤であることが好ましい。
Of these, when two or more plasticizers are used, at least one is preferably a polyhydric alcohol ester plasticizer.
多価アルコールエステル系可塑剤は2価以上の脂肪族多価アルコールとモノカルボン酸のエステルよりなる可塑剤であり、分子内に芳香環またはシクロアルキル環を有することが好ましい。好ましくは2~20価の脂肪族多価アルコールエステルである。
The polyhydric alcohol ester plasticizer is a plasticizer composed of an ester of a divalent or higher aliphatic polyhydric alcohol and a monocarboxylic acid, and preferably has an aromatic ring or a cycloalkyl ring in the molecule. A divalent to 20-valent aliphatic polyhydric alcohol ester is preferred.
本発明に好ましく用いられる多価アルコールは次の一般式(a)で表される。
The polyhydric alcohol preferably used in the present invention is represented by the following general formula (a).
一般式(a) R11-(OH)n
但し、R11はn価の有機基、nは2以上の正の整数、OH基はアルコール性、および/またはフェノール性水酸基を表す。 Formula (a) R 11 — (OH) n
However, R 11 represents an n-valent organic group, n represents a positive integer of 2 or more, and the OH group represents an alcoholic and / or phenolic hydroxyl group.
但し、R11はn価の有機基、nは2以上の正の整数、OH基はアルコール性、および/またはフェノール性水酸基を表す。 Formula (a) R 11 — (OH) n
However, R 11 represents an n-valent organic group, n represents a positive integer of 2 or more, and the OH group represents an alcoholic and / or phenolic hydroxyl group.
以下に、多価アルコールエステルの具体的化合物を例示する。
The following are specific compounds of polyhydric alcohol esters.
グリコレート系可塑剤は特に限定されないが、アルキルフタリルアルキルグリコレート類が好ましく用いることができる。
The glycolate plasticizer is not particularly limited, but alkylphthalylalkyl glycolates can be preferably used.
アルキルフタリルアルキルグリコレート類としては、例えばメチルフタリルメチルグリコレート、エチルフタリルエチルグリコレート、プロピルフタリルプロピルグリコレート、ブチルフタリルブチルグリコレート、オクチルフタリルオクチルグリコレート、メチルフタリルエチルグリコレート、エチルフタリルメチルグリコレート、エチルフタリルプロピルグリコレート、メチルフタリルブチルグリコレート、エチルフタリルブチルグリコレート、ブチルフタリルメチルグリコレート、ブチルフタリルエチルグリコレート、プロピルフタリルブチルグリコレート、ブチルフタリルプロピルグリコレート、メチルフタリルオクチルグリコレート、エチルフタリルオクチルグリコレート、オクチルフタリルメチルグリコレート、オクチルフタリルエチルグリコレート等が挙げられる。
Examples of alkyl phthalyl alkyl glycolates include methyl phthalyl methyl glycolate, ethyl phthalyl ethyl glycolate, propyl phthalyl propyl glycolate, butyl phthalyl butyl glycolate, octyl phthalyl octyl glycolate, methyl phthalyl ethyl Glycolate, ethyl phthalyl methyl glycolate, ethyl phthalyl propyl glycolate, methyl phthalyl butyl glycolate, ethyl phthalyl butyl glycolate, butyl phthalyl methyl glycolate, butyl phthalyl ethyl glycolate, propyl phthalyl butyl glycol Butyl phthalyl propyl glycolate, methyl phthalyl octyl glycolate, ethyl phthalyl octyl glycolate, octyl phthalyl methyl glycolate, octyl phthalate Ethyl glycolate, and the like.
フタル酸エステル系可塑剤としては、ジエチルフタレート、ジメトキシエチルフタレート、ジメチルフタレート、ジオクチルフタレート、ジブチルフタレート、ジ-2-エチルヘキシルフタレート、ジオクチルフタレート、ジシクロヘキシルフタレート、ジシクロヘキシルテレフタレート等が挙げられる。
Examples of the phthalate ester plasticizer include diethyl phthalate, dimethoxyethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, dioctyl phthalate, dicyclohexyl phthalate, and dicyclohexyl terephthalate.
クエン酸エステル系可塑剤としては、クエン酸アセチルトリメチル、クエン酸アセチルトリエチル、クエン酸アセチルトリブチル等が挙げられる。
Examples of the citrate plasticizer include acetyl trimethyl citrate, acetyl triethyl citrate, and acetyl tributyl citrate.
脂肪酸エステル系可塑剤として、オレイン酸ブチル、リシノール酸メチルアセチル、セバシン酸ジブチル等が挙げられる。
Examples of fatty acid ester plasticizers include butyl oleate, methylacetyl ricinoleate, and dibutyl sebacate.
リン酸エステル系可塑剤としては、トリフェニルホスフェート、トリクレジルホスフェート、クレジルジフェニルホスフェート、オクチルジフェニルホスフェート、ジフェニルビフェニルホスフェート、トリオクチルホスフェート、トリブチルホスフェート等が挙げられる。
Examples of the phosphate ester plasticizer include triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, diphenyl biphenyl phosphate, trioctyl phosphate, tributyl phosphate, and the like.
多価カルボン酸エステル化合物としては、2価以上、好ましくは2価~20価の多価カルボン酸とアルコールのエステルよりなる。また、脂肪族多価カルボン酸は2~20価であることが好ましく、芳香族多価カルボン酸、脂環式多価カルボン酸の場合は3価~20価であることが好ましい。
The polyvalent carboxylic acid ester compound is composed of an ester of a divalent or higher, preferably a divalent to 20valent polyvalent carboxylic acid and an alcohol. The aliphatic polyvalent carboxylic acid is preferably divalent to 20-valent, and in the case of an aromatic polyvalent carboxylic acid or alicyclic polyvalent carboxylic acid, it is preferably trivalent to 20-valent.
多価カルボン酸は次の一般式(b)で表される。
The polyvalent carboxylic acid is represented by the following general formula (b).
一般式(b) R12(COOH)m1(OH)n1
式中、R12は(m1+n1)価の有機基、m1は2以上の正の整数、n1は0以上の整数、COOH基はカルボキシル基、OH基はアルコール性またはフェノール性水酸基を表す。 Formula (b) R 12 (COOH) m1 (OH) n1
In the formula, R 12 represents an (m1 + n1) -valent organic group, m1 represents a positive integer of 2 or more, n1 represents an integer of 0 or more, a COOH group represents a carboxyl group, and an OH group represents an alcoholic or phenolic hydroxyl group.
式中、R12は(m1+n1)価の有機基、m1は2以上の正の整数、n1は0以上の整数、COOH基はカルボキシル基、OH基はアルコール性またはフェノール性水酸基を表す。 Formula (b) R 12 (COOH) m1 (OH) n1
In the formula, R 12 represents an (m1 + n1) -valent organic group, m1 represents a positive integer of 2 or more, n1 represents an integer of 0 or more, a COOH group represents a carboxyl group, and an OH group represents an alcoholic or phenolic hydroxyl group.
多価カルボン酸エステル化合物の分子量は特に制限はないが、分子量300~1000の範囲であることが好ましく、350~750の範囲であることが更に好ましい。保留性向上の点では大きい方が好ましく、透湿性、セルロースアセテートとの相溶性の点では小さい方が好ましい。
The molecular weight of the polyvalent carboxylic acid ester compound is not particularly limited, but is preferably in the range of 300 to 1000, and more preferably in the range of 350 to 750. The larger one is preferable in terms of improvement in retention, and the smaller one is preferable in terms of moisture permeability and compatibility with cellulose acetate.
本発明に用いることのできる多価カルボン酸エステルに用いられるアルコール類は一種類でも良いし、二種以上の混合であっても良い。
The alcohol used for the polyvalent carboxylic acid ester that can be used in the present invention may be one kind or a mixture of two or more kinds.
特に好ましい多価カルボン酸エステル化合物の例としては、例えば、トリエチルシトレート、トリブチルシトレート、アセチルトリエチルシトレート(ATEC)、アセチルトリブチルシトレート(ATBC)、ベンゾイルトリブチルシトレート、アセチルトリフェニルシトレート、アセチルトリベンジルシトレート、酒石酸ジブチル、酒石酸ジアセチルジブチル、トリメリット酸トリブチル、ピロメリット酸テトラブチル等が挙げられる。
Examples of particularly preferable polyvalent carboxylic acid ester compounds include, for example, triethyl citrate, tributyl citrate, acetyl triethyl citrate (ATEC), acetyl tributyl citrate (ATBC), benzoyl tributyl citrate, acetyl triphenyl citrate, Acetyl tribenzyl citrate, dibutyl tartrate, diacetyl dibutyl tartrate, tributyl trimellitic acid, tetrabutyl pyromellitic acid and the like can be mentioned.
本発明のセルロースエステルフィルムにおいて可塑剤は、セルロースエステルフィルムの1~40質量%の範囲で適宜使用することができる。
In the cellulose ester film of the present invention, the plasticizer can be appropriately used in the range of 1 to 40% by mass of the cellulose ester film.
(紫外線吸収剤)
本発明のセルロースエステルフィルムは、紫外線吸収剤を含有することもできる。紫外線吸収剤は400nm以下の紫外線を吸収することで、耐久性を向上させることを目的としており、特に波長370nmでの透過率が10%以下であることが好ましく、より好ましくは5%以下、更に好ましくは2%以下である。 (UV absorber)
The cellulose ester film of the present invention can also contain an ultraviolet absorber. The ultraviolet absorber is intended to improve durability by absorbing ultraviolet light having a wavelength of 400 nm or less, and the transmittance at a wavelength of 370 nm is particularly preferably 10% or less, more preferably 5% or less. Preferably it is 2% or less.
本発明のセルロースエステルフィルムは、紫外線吸収剤を含有することもできる。紫外線吸収剤は400nm以下の紫外線を吸収することで、耐久性を向上させることを目的としており、特に波長370nmでの透過率が10%以下であることが好ましく、より好ましくは5%以下、更に好ましくは2%以下である。 (UV absorber)
The cellulose ester film of the present invention can also contain an ultraviolet absorber. The ultraviolet absorber is intended to improve durability by absorbing ultraviolet light having a wavelength of 400 nm or less, and the transmittance at a wavelength of 370 nm is particularly preferably 10% or less, more preferably 5% or less. Preferably it is 2% or less.
紫外線吸収剤の使用量は、紫外線吸収剤の種類、使用条件等により一様ではないが、偏光板保護フィルムの乾燥膜厚が30~200μmの場合は、偏光板保護フィルムに対して0.5~10質量%が好ましく、0.6~4質量%が更に好ましい。
The amount of the UV absorber used is not uniform depending on the type of UV absorber, the operating conditions, etc., but when the dry film thickness of the polarizing plate protective film is 30 to 200 μm, the amount used is 0.5 to the polarizing plate protective film. Is preferably 10 to 10% by mass, and more preferably 0.6 to 4% by mass.
(酸化防止剤)
酸化防止剤は劣化防止剤ともいわれる。高湿高温の状態に液晶画像表示装置などがおかれた場合には、セルロースアセテートフィルムの劣化が起こる場合がある。 (Antioxidant)
Antioxidants are also referred to as deterioration inhibitors. When a liquid crystal image display device or the like is placed in a high humidity and high temperature state, the cellulose acetate film may be deteriorated.
酸化防止剤は劣化防止剤ともいわれる。高湿高温の状態に液晶画像表示装置などがおかれた場合には、セルロースアセテートフィルムの劣化が起こる場合がある。 (Antioxidant)
Antioxidants are also referred to as deterioration inhibitors. When a liquid crystal image display device or the like is placed in a high humidity and high temperature state, the cellulose acetate film may be deteriorated.
酸化防止剤は、例えば、セルロースアセテートフィルム中の残留溶媒量のハロゲンやリン酸系可塑剤のリン酸等によりセルロースアセテートフィルムが分解するのを遅らせたり、防いだりする役割を有するので、前記セルロースアセテートフィルム中に含有させるのが好ましい。
The antioxidant has a role of delaying or preventing the cellulose acetate film from being decomposed by, for example, the residual solvent amount of halogen in the cellulose acetate film or phosphoric acid of the phosphoric acid plasticizer. It is preferable to make it contain in a film.
このような酸化防止剤としては、ヒンダードフェノール系の化合物が好ましく用いられ、例えば、2,6-ジ-t-ブチル-p-クレゾール、ペンタエリスリチル-テトラキス〔3-(3,5-ジ-t-ブチル-4-ヒドロキシフェニル)プロピオネート〕、トリエチレングリコール-ビス〔3-(3-t-ブチル-5-メチル-4-ヒドロキシフェニル)プロピオネート〕、1,6-ヘキサンジオール-ビス〔3-(3,5-ジ-t-ブチル-4-ヒドロキシフェニル)プロピオネート〕、2,4-ビス-(n-オクチルチオ)-6-(4-ヒドロキシ-3,5-ジ-t-ブチルアニリノ)-1,3,5-トリアジン、2,2-チオ-ジエチレンビス〔3-(3,5-ジ-t-ブチル-4-ヒドロキシフェニル)プロピオネート〕、オクタデシル-3-(3,5-ジ-t-ブチル-4-ヒドロキシフェニル)プロピオネート、N,N′-ヘキサメチレンビス(3,5-ジ-t-ブチル-4-ヒドロキシ-ヒドロシンナマミド)、1,3,5-トリメチル-2,4,6-トリス(3,5-ジ-t-ブチル-4-ヒドロキシベンジル)ベンゼン、トリス-(3,5-ジ-t-ブチル-4-ヒドロキシベンジル)-イソシアヌレイト等を挙げることができる。
As such an antioxidant, a hindered phenol compound is preferably used. For example, 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) propionate, N, N'-hexamethylenebis (3,5-di-t-butyl-4-hydroxy-hydrocinnamamide) 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tris- (3,5-di-t-butyl-4-hydroxy Benzyl) -isocyanurate and the like.
特に、2,6-ジ-t-ブチル-p-クレゾール、ペンタエリスリチル-テトラキス〔3-(3,5-ジ-t-ブチル-4-ヒドロキシフェニル)プロピオネート〕、トリエチレングリコール-ビス〔3-(3-t-ブチル-5-メチル-4-ヒドロキシフェニル)プロピオネート〕が好ましい。また、例えば、N,N′-ビス〔3-(3,5-ジ-t-ブチル-4-ヒドロキシフェニル)プロピオニル〕ヒドラジン等のヒドラジン系の金属不活性剤やトリス(2,4-ジ-t-ブチルフェニル)フォスファイト等のリン系加工安定剤を併用してもよい。
In particular, 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. Further, for example, hydrazine-based metal deactivators such as N, N′-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine and tris (2,4-di- A phosphorus processing stabilizer such as t-butylphenyl) phosphite may be used in combination.
これらの化合物の添加量は、セルロース誘導体に対して質量割合で1ppm~1.0%が好ましく、10~1000ppmが更に好ましい。
The amount of these compounds added is preferably 1 ppm to 1.0%, more preferably 10 to 1000 ppm in terms of mass ratio with respect to the cellulose derivative.
〈微粒子〉
本発明のセルロースエステルフィルムには、取扱性を向上させる為、例えば二酸化ケイ素、二酸化チタン、酸化アルミニウム、酸化ジルコニウム、炭酸カルシウム、カオリン、タルク、焼成ケイ酸カルシウム、水和ケイ酸カルシウム、ケイ酸アルミニウム、ケイ酸マグネシウム、リン酸カルシウム等の無機微粒子や架橋高分子などのマット剤を含有させることが好ましい。中でも二酸化ケイ素がフィルムのヘイズを小さくできるので好ましい。 <Fine particles>
The cellulose ester film of the present invention has, for example, silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, kaolin, talc, calcined calcium silicate, hydrated calcium silicate, aluminum silicate in order to improve handleability. Further, it is preferable to contain inorganic fine particles such as magnesium silicate and calcium phosphate and a matting agent such as a crosslinked polymer. Of these, silicon dioxide is preferable because it can reduce the haze of the film.
本発明のセルロースエステルフィルムには、取扱性を向上させる為、例えば二酸化ケイ素、二酸化チタン、酸化アルミニウム、酸化ジルコニウム、炭酸カルシウム、カオリン、タルク、焼成ケイ酸カルシウム、水和ケイ酸カルシウム、ケイ酸アルミニウム、ケイ酸マグネシウム、リン酸カルシウム等の無機微粒子や架橋高分子などのマット剤を含有させることが好ましい。中でも二酸化ケイ素がフィルムのヘイズを小さくできるので好ましい。 <Fine particles>
The cellulose ester film of the present invention has, for example, silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, kaolin, talc, calcined calcium silicate, hydrated calcium silicate, aluminum silicate in order to improve handleability. Further, it is preferable to contain inorganic fine particles such as magnesium silicate and calcium phosphate and a matting agent such as a crosslinked polymer. Of these, silicon dioxide is preferable because it can reduce the haze of the film.
微粒子の1次平均粒子径としては、20nm以下が好ましく、更に好ましくは、5~16nmであり、特に好ましくは、5~12nmである。添加量は、適宜さだめることができる。
<セルロースエステルフィルムの製造方法>
次に、本発明のセルロースエステルフィルムの製造方法について説明する。 The primary average particle diameter of the fine particles is preferably 20 nm or less, more preferably 5 to 16 nm, and particularly preferably 5 to 12 nm. The amount added can be appropriately determined.
<Method for producing cellulose ester film>
Next, the manufacturing method of the cellulose-ester film of this invention is demonstrated.
<セルロースエステルフィルムの製造方法>
次に、本発明のセルロースエステルフィルムの製造方法について説明する。 The primary average particle diameter of the fine particles is preferably 20 nm or less, more preferably 5 to 16 nm, and particularly preferably 5 to 12 nm. The amount added can be appropriately determined.
<Method for producing cellulose ester film>
Next, the manufacturing method of the cellulose-ester film of this invention is demonstrated.
本発明のセルロースエステルフィルムは溶液流延法で製造されたフィルムであっても溶融流延法で製造されたフィルムであっても好ましく用いることができる。
The cellulose ester film of the present invention can be preferably used regardless of whether it is a film produced by a solution casting method or a film produced by a melt casting method.
本発明のセルロースエステルフィルムの溶液流延法での製造は、セルロースエステルおよび添加剤を溶剤に溶解させてドープを調製する工程、ドープを無限に移行する無端の金属支持体上に流延する工程、流延したドープをウェブとして乾燥する工程、金属支持体から剥離する工程、延伸または幅保持する工程、更に乾燥する工程、仕上がったフィルムを巻取る工程により行われる。
Production of the cellulose ester film of the present invention by the solution casting method is a step of preparing a dope by dissolving cellulose ester and additives in a solvent, a step of casting the dope on an endless metal support that moves infinitely It is performed by a step of drying the cast dope as a web, a step of peeling from the metal support, a step of stretching or maintaining the width, a step of further drying, and a step of winding up the finished film.
ドープを調製する工程について述べる。ドープ中のセルロースエステルの濃度は、濃い方が金属支持体に流延した後の乾燥負荷が低減できて好ましいが、セルロースエステルの濃度が濃過ぎると濾過時の負荷が増えて、濾過精度が悪くなる。これらを両立する濃度としては、10~35質量%が好ましく、更に好ましくは、15~25質量%である。
The process for preparing the dope will be described. The concentration of cellulose ester in the dope is preferably higher because the drying load after casting on the metal support can be reduced. However, if the concentration of cellulose ester is too high, the load during filtration increases and the filtration accuracy is poor. Become. The concentration that achieves both of these is preferably 10 to 35% by mass, and more preferably 15 to 25% by mass.
ドープで用いられる溶剤は、単独で用いても2種以上を併用してもよいが、セルロースエステルの良溶剤と貧溶剤を混合して使用することが生産効率の点で好ましく、良溶剤が多い方がセルロースエステルの溶解性の点で好ましい。
The solvent used in the dope may be used alone or in combination of two or more, but it is preferable to use a mixture of a good solvent and a poor solvent of cellulose ester in terms of production efficiency, and there are many good solvents. This is preferable from the viewpoint of the solubility of the cellulose ester.
良溶剤と貧溶剤の混合比率の好ましい範囲は、良溶剤が70~98質量%であり、貧溶剤が2~30質量%である。良溶剤、貧溶剤とは、使用するセルロースエステルを単独で溶解するものを良溶剤、単独で膨潤するかまたは溶解しないものを貧溶剤と定義している。
A preferable range of the mixing ratio of the good solvent and the poor solvent is 70 to 98% by mass for the good solvent and 2 to 30% by mass for the poor solvent. With a good solvent and a poor solvent, what dissolve | melts the cellulose ester to be used independently is defined as a good solvent, and what poorly swells or does not melt | dissolve is defined as a poor solvent.
そのため、セルロースエステルの平均酢化度(アセチル基置換度)によって良溶剤、貧溶剤が変わる。
Therefore, the good solvent and the poor solvent change depending on the average acetylation degree (acetyl group substitution degree) of the cellulose ester.
本発明に用いられる良溶剤は特に限定されないが、メチレンクロライド等の有機ハロゲン化合物やジオキソラン類、アセトン、酢酸メチル、アセト酢酸メチル等が挙げられる。特に好ましくはメチレンクロライドまたは酢酸メチルが挙げられる。
The good solvent used in the present invention is not particularly limited, and examples thereof include organic halogen compounds such as methylene chloride, dioxolanes, acetone, methyl acetate, and methyl acetoacetate. Particularly preferred is methylene chloride or methyl acetate.
また、本発明に用いられる貧溶剤は特に限定されないが、例えば、メタノール、エタノール、n-ブタノール、シクロヘキサン、シクロヘキサノン等が好ましく用いられる。また、ドープ中には水が0.01~2質量%含有していることが好ましい。
The poor solvent used in the present invention is not particularly limited, but for example, methanol, ethanol, n-butanol, cyclohexane, cyclohexanone and the like are preferably used. The dope preferably contains 0.01 to 2% by mass of water.
また、セルロースエステルの溶解に用いられる溶媒は、フィルム製膜工程で乾燥によりフィルムから除去された溶媒を回収し、これを再利用して用いられる。
Also, the solvent used for dissolving the cellulose ester is used by collecting the solvent removed from the film by drying in the film-forming process and reusing it.
回収溶剤中に、セルロースエステルに添加されている添加剤、例えば可塑剤、紫外線吸収剤、ポリマー、モノマー成分などが微量含有されていることもあるが、これらが含まれていても好ましく再利用することができるし、必要であれば精製して再利用することもできる。
The recovery solvent may contain trace amounts of additives added to the cellulose ester, such as plasticizers, UV absorbers, polymers, monomer components, etc., but even if these are included, they are preferably reused. Can be purified and reused if necessary.
上記記載のドープを調製する時の、セルロースエステルの溶解方法としては、一般的な方法を用いることができる。加熱と加圧を組み合わせると常圧における沸点以上に加熱できる。
As a method for dissolving the cellulose ester when preparing the dope described above, a general method can be used. When heating and pressurization are combined, it is possible to heat above the boiling point at normal pressure.
溶剤の常圧での沸点以上でかつ加圧下で溶剤が沸騰しない範囲の温度で加熱しながら攪拌溶解すると、ゲルやママコと呼ばれる塊状未溶解物の発生を防止するため好ましい。
It is preferable to stir and dissolve while heating at a temperature that is higher than the boiling point of the solvent at normal pressure and that the solvent does not boil under pressure, in order to prevent the formation of massive undissolved material called gel or mamako.
また、セルロースエステルを貧溶剤と混合して湿潤あるいは膨潤させた後、更に良溶剤を添加して溶解する方法も好ましく用いられる。
In addition, a method in which a cellulose ester is mixed with a poor solvent and wetted or swollen, and then a good solvent is added and dissolved is also preferably used.
加圧は窒素ガス等の不活性気体を圧入する方法や、加熱によって溶剤の蒸気圧を上昇させる方法によって行ってもよい。加熱は外部から行うことが好ましく、例えばジャケットタイプのものは温度コントロールが容易で好ましい。
Pressurization may be performed by a method of injecting an inert gas such as nitrogen gas or a method of increasing the vapor pressure of the solvent by heating. Heating is preferably performed from the outside. For example, a jacket type is preferable because temperature control is easy.
溶剤を添加しての加熱温度は、高い方がセルロースエステルの溶解性の観点から好ましいが、加熱温度が高過ぎると必要とされる圧力が大きくなり生産性が悪くなる。
The heating temperature with the addition of the solvent is preferably higher from the viewpoint of the solubility of the cellulose ester, but if the heating temperature is too high, the required pressure increases and the productivity deteriorates.
好ましい加熱温度は45~120℃であり、60~110℃がより好ましく、70℃~105℃が更に好ましい。また、圧力は設定温度で溶剤が沸騰しないように調整される。
The preferred heating temperature is 45 to 120 ° C, more preferably 60 to 110 ° C, and still more preferably 70 ° C to 105 ° C. The pressure is adjusted so that the solvent does not boil at the set temperature.
もしくは冷却溶解法も好ましく用いられ、これによって酢酸メチルなどの溶媒にセルロースエステルを溶解させることができる。
Alternatively, a cooling dissolution method is also preferably used, whereby the cellulose ester can be dissolved in a solvent such as methyl acetate.
次に、このセルロースエステル溶液を濾紙等の適当な濾過材を用いて濾過する。濾過材としては、不溶物等を除去するために絶対濾過精度が小さい方が好ましいが、絶対濾過精度が小さ過ぎると濾過材の目詰まりが発生し易いという問題がある。
Next, the cellulose ester solution is filtered using an appropriate filter medium such as filter paper. As the filter medium, it is preferable that the absolute filtration accuracy is small in order to remove insoluble matters and the like, but there is a problem that the filter medium is likely to be clogged if the absolute filtration accuracy is too small.
このため絶対濾過精度0.008mm以下の濾材が好ましく、0.001~0.008mmの濾材がより好ましく、0.003~0.006mmの濾材が更に好ましい。
For this reason, a filter medium with an absolute filtration accuracy of 0.008 mm or less is preferable, a filter medium with 0.001 to 0.008 mm is more preferable, and a filter medium with 0.003 to 0.006 mm is still more preferable.
濾材の材質は特に制限はなく、通常の濾材を使用することができるが、ポリプロピレン、テフロン(登録商標)等のプラスチック製の濾材や、ステンレススティール等の金属製の濾材が繊維の脱落等がなく好ましい。
There are no particular restrictions on the material of the filter medium, and ordinary filter media can be used. However, plastic filter media such as polypropylene and Teflon (registered trademark), and metal filter media such as stainless steel do not drop off fibers. preferable.
濾過により、原料のセルロースエステルに含まれていた不純物、特に輝点異物を除去、低減することが好ましい。
It is preferable to remove and reduce impurities, particularly bright spot foreign matter, contained in the raw material cellulose ester by filtration.
輝点異物とは、2枚の偏光板をクロスニコル状態にして配置し、その間に光学フィルム等を置き、一方の偏光板の側から光を当てて、他方の偏光板の側から観察した時に反対側からの光が漏れて見える点(異物)のことであり、径が0.01mm以上である輝点数が200個/cm2以下であることが好ましい。
Bright spot foreign matter means that when two polarizing plates are placed in a crossed Nicol state, an optical film or the like is placed between them, light is applied from one polarizing plate side, and observation is performed from the other polarizing plate side. It is a point (foreign matter) where light from the opposite side appears to leak, and the number of bright spots having a diameter of 0.01 mm or more is preferably 200 / cm 2 or less.
より好ましくは100個/cm2以下であり、更に好ましくは50個/m2以下であり、更に好ましくは0~10個/cm2以下である。また、0.01mm以下の輝点も少ない方が好ましい。
More preferably, it is 100 pieces / cm 2 or less, still more preferably 50 pieces / m 2 or less, still more preferably 0 to 10 pieces / cm 2 . Further, it is preferable that the number of bright spots of 0.01 mm or less is small.
ドープの濾過は通常の方法で行うことができるが、溶剤の常圧での沸点以上で、かつ加圧下で溶剤が沸騰しない範囲の温度で加熱しながら濾過する方法が、濾過前後の濾圧の差(差圧という)の上昇が小さく、好ましい。
The dope can be filtered by a normal method, but the method of filtering while heating at a temperature not lower than the boiling point of the solvent at normal pressure and in a range where the solvent does not boil under pressure is the filtration pressure before and after filtration. The increase in the difference (referred to as differential pressure) is small and preferable.
好ましい温度は45~120℃であり、45~70℃がより好ましく、45~55℃であることが更に好ましい。
The preferred temperature is 45 to 120 ° C, more preferably 45 to 70 ° C, and still more preferably 45 to 55 ° C.
濾圧は小さい方が好ましい。濾圧は1.6MPa以下であることが好ましく、1.2MPa以下であることがより好ましく、1.0MPa以下であることが更に好ましい。
A smaller filtration pressure is preferable. The filtration pressure is preferably 1.6 MPa or less, more preferably 1.2 MPa or less, and further preferably 1.0 MPa or less.
ここで、ドープの流延について説明する。
Here, the dope casting will be described.
流延(キャスト)工程における金属支持体は、表面を鏡面仕上げしたものが好ましく、金属支持体としては、ステンレススティールベルトもしくは鋳物で表面をメッキ仕上げしたドラムが好ましく用いられる。
The metal support in the casting process is preferably a mirror-finished surface, and a stainless steel belt or a drum whose surface is plated with a casting is preferably used as the metal support.
キャストの幅は1~4mとすることができる。流延工程の金属支持体の表面温度は-50℃~溶剤の沸点未満の温度で、温度が高い方がウェブの乾燥速度が速くできるので好ましいが、余り高過ぎるとウェブが発泡したり、平面性が劣化する場合がある。
The cast width can be 1 ~ 4m. The surface temperature of the metal support in the casting step is −50 ° C. to less than the boiling point of the solvent, and a higher temperature is preferable because the web drying speed can be increased. May deteriorate.
好ましい支持体温度は0~55℃であり、25~50℃が更に好ましい。あるいは、冷却することによってウェブをゲル化させて残留溶媒を多く含んだ状態でドラムから剥離することも好ましい方法である。
The preferred support temperature is 0 to 55 ° C, more preferably 25 to 50 ° C. Alternatively, it is also a preferable method that the web is gelled by cooling and peeled from the drum in a state containing a large amount of residual solvent.
金属支持体の温度を制御する方法は特に制限されないが、温風または冷風を吹きかける方法や、温水を金属支持体の裏側に接触させる方法がある。温水を用いる方が熱の伝達が効率的に行われるため、金属支持体の温度が一定になるまでの時間が短く好ましい。温風を用いる場合は目的の温度よりも高い温度の風を使う場合がある。
The method for controlling the temperature of the metal support is not particularly limited, but there are a method of blowing hot air or cold air, and a method of contacting hot water with the back side of the metal support. It is preferable to use warm water because heat transfer is performed efficiently, so that the time until the temperature of the metal support becomes constant is short. When warm air is used, wind at a temperature higher than the target temperature may be used.
セルロースエステルフィルムが良好な平面性を示すためには、金属支持体からウェブを剥離する際の残留溶媒量は10~150質量%が好ましく、更に好ましくは20~40質量%または60~130質量%であり、特に好ましくは、20~30質量%または70~120質量%である。
In order for the cellulose ester film to exhibit good flatness, the amount of residual solvent when peeling the web from the metal support is preferably 10 to 150% by mass, more preferably 20 to 40% by mass or 60 to 130% by mass. Particularly preferred is 20 to 30% by mass or 70 to 120% by mass.
本発明においては、残留溶媒量は下記式で定義される。
In the present invention, the amount of residual solvent is defined by the following formula.
残留溶媒量(質量%)={(M-N)/N}×100
尚、Mはウェブまたはフィルムを製造中または製造後の任意の時点で採取した試料の質量で、NはMを115℃で1時間の加熱後の質量である。 Residual solvent amount (% by mass) = {(MN) / N} × 100
M is the mass of a sample collected during or after the production of the web or film, and N is the mass after heating M at 115 ° C. for 1 hour.
尚、Mはウェブまたはフィルムを製造中または製造後の任意の時点で採取した試料の質量で、NはMを115℃で1時間の加熱後の質量である。 Residual solvent amount (% by mass) = {(MN) / N} × 100
M is the mass of a sample collected during or after the production of the web or film, and N is the mass after heating M at 115 ° C. for 1 hour.
また、セルロースエステルフィルムの乾燥工程においては、ウェブを金属支持体より剥離し、更に乾燥し、残留溶媒量を1質量%以下にすることが好ましく、更に好ましくは0.1質量%以下であり、特に好ましくは0~0.01質量%以下である。
Further, in the drying step of the cellulose ester film, the web is peeled off from the metal support, and further dried, and the residual solvent amount is preferably 1% by mass or less, more preferably 0.1% by mass or less, Particularly preferred is 0 to 0.01% by mass or less.
フィルム乾燥工程では一般にロール乾燥方式(上下に配置した多数のロールにウェブを交互に通し乾燥させる方式)やテンター方式でウェブを搬送させながら乾燥する方式が採られる。
In the film drying process, generally, a roll drying method (a method in which webs are alternately passed through a plurality of rolls arranged above and below) and a method in which the web is dried while being conveyed by a tenter method are employed.
本発明のセルロースエステルフィルムを作製するためには、ウェブの両端をクリップ等で把持するテンター方式で幅方向(横方向)に延伸を行うことが特に好ましい。剥離張力は300N/m以下で剥離することが好ましい。
In order to produce the cellulose ester film of the present invention, it is particularly preferable to perform stretching in the width direction (lateral direction) by a tenter method in which both ends of the web are held with clips or the like. Peeling is preferably performed at a peeling tension of 300 N / m or less.
ウェブを乾燥させる手段は特に制限なく、一般的に熱風、赤外線、加熱ロール、マイクロ波等で行うことができるが、簡便さの点で熱風で行うことが好ましい。
The means for drying the web is not particularly limited, and can be generally performed with hot air, infrared rays, a heating roll, microwave, or the like, but is preferably performed with hot air in terms of simplicity.
ウェブの乾燥工程における乾燥温度は40~200℃で段階的に高くしていくことが好ましい。
It is preferable that the drying temperature in the web drying process is increased stepwise from 40 to 200 ° C.
セルロースエステルフィルムの膜厚は、特に限定はされないが10~200μmが用いられる。特に膜厚は10~100μmであることが特に好ましい。更に好ましくは20~60μmである。
The film thickness of the cellulose ester film is not particularly limited, but 10 to 200 μm is used. In particular, the film thickness is particularly preferably 10 to 100 μm. More preferably, it is 20 to 60 μm.
本発明のセルロースエステルフィルムは、幅1~4mのものが用いられる。特に幅1.4~4mのものが好ましく用いられ、特に好ましくは1.6~3mである。4mを超えると搬送が困難となる。
The cellulose ester film of the present invention has a width of 1 to 4 m. Particularly, those having a width of 1.4 to 4 m are preferably used, and particularly preferably 1.6 to 3 m. If it exceeds 4 m, conveyance becomes difficult.
本発明で目標とするレターデーション値Ro、Rtを得るには、セルロースエステルフィルムが本発明の構成をとり、更に搬送張力の制御、延伸操作により屈折率制御を行うことが好ましい。
In order to obtain the target retardation values Ro and Rt in the present invention, it is preferable that the cellulose ester film has the structure of the present invention, and the refractive index is controlled by controlling the transport tension and stretching.
例えば、長手方向の張力を低くまたは高くすることでレターデーション値を変動させることが可能となる。
For example, the retardation value can be changed by lowering or increasing the tension in the longitudinal direction.
また、フィルムの長手方向(製膜方向)およびそれとフィルム面内で直交する方向、即ち幅手方向に対して、逐次または同時に2軸延伸もしくは1軸延伸することができる。
In addition, the film can be biaxially or uniaxially stretched sequentially or simultaneously in the longitudinal direction (film forming direction) of the film and the direction orthogonal to the longitudinal direction of the film, that is, the width direction.
互いに直交する2軸方向の延伸倍率は、それぞれ最終的には流延方向に0.8~1.5倍、幅方向に1.1~2.5倍の範囲とすることが好ましく、流延方向に0.8~1.0倍、幅方向に1.2~2.0倍に範囲で行うことが好ましい。
The draw ratios in the biaxial directions perpendicular to each other are preferably in the range of 0.8 to 1.5 times in the casting direction and 1.1 to 2.5 times in the width direction, respectively. It is preferable to carry out in the range of 0.8 to 1.0 times in the direction and 1.2 to 2.0 times in the width direction.
延伸温度は120℃~200℃が好ましく、さらに好ましくは150℃~200℃であり、さらに好ましくは150℃を超えて190℃以下で延伸するのが好ましい。
The stretching temperature is preferably 120 ° C. to 200 ° C., more preferably 150 ° C. to 200 ° C., more preferably more than 150 ° C. and 190 ° C. or less.
フィルム中の残留溶媒は20~0%が好ましく、さらに好ましくは15~0%で延伸するのが好ましい。
The residual solvent in the film is preferably 20 to 0%, more preferably 15 to 0%.
具体的には155℃で残留溶媒が11%で延伸する、あるいは155℃で残留溶媒が2%で延伸するのが好ましい。もしくは160℃で残留溶媒が11%で延伸するのが好ましく、あるいは160℃で残留溶媒が1%未満で延伸するのが好ましい。
Specifically, it is preferable that the residual solvent is stretched by 11% at 155 ° C., or the residual solvent is stretched by 2% at 155 ° C. Alternatively, it is preferable that the residual solvent is stretched at 11% at 160 ° C, or the residual solvent is stretched at less than 1% at 160 ° C.
ウェブを延伸する方法には特に限定はない。例えば、複数のロールに周速差をつけ、その間でロール周速差を利用して縦方向に延伸する方法、ウェブの両端をクリップやピンで固定し、クリップやピンの間隔を進行方向に広げて縦方向に延伸する方法、同様に横方向に広げて横方向に延伸する方法、あるいは縦横同時に広げて縦横両方向に延伸する方法などが挙げられる。もちろんこれ等の方法は、組み合わせて用いてもよい。
There is no particular limitation on the method of stretching the web. For example, a method in which a difference in peripheral speed is applied to a plurality of rolls, and the roll peripheral speed difference is used to stretch in the longitudinal direction, the both ends of the web are fixed with clips and pins, and the interval between the clips and pins is increased in the traveling direction. And a method of stretching in the vertical direction, a method of stretching in the horizontal direction and stretching in the horizontal direction, a method of stretching in the vertical and horizontal directions and stretching in both the vertical and horizontal directions, and the like. Of course, these methods may be used in combination.
また、所謂テンター法の場合、リニアドライブ方式でクリップ部分を駆動すると滑らかな延伸を行うことができ、破断等の危険性が減少できるので好ましい。
Also, in the case of the so-called tenter method, driving the clip portion by the linear drive method is preferable because smooth stretching can be performed and the risk of breakage and the like can be reduced.
製膜工程のこれらの幅保持あるいは横方向の延伸はテンターによって行うことが好ましく、ピンテンターでもクリップテンターでもよい。
It is preferable to carry out the width maintenance or lateral stretching in the film forming step by a tenter, and it may be a pin tenter or a clip tenter.
本発明のセルロースエステルフィルムの遅相軸または進相軸がフィルム面内に存在し、製膜方向とのなす角をθ1とするとθ1は-1°以上+1°以下であることが好ましく、-0.5°以上+0.5°以下であることがより好ましい。
The slow axis or the fast axis of the cellulose ester film of the present invention exists in the film plane, and θ1 is preferably −1 ° or more and + 1 ° or less, assuming that the angle formed with the film forming direction is θ1. More preferably, it is 5 ° or more and + 0.5 ° or less.
このθ1は配向角として定義でき、θ1の測定は、自動複屈折計KOBRA-21ADH(王子計測機器)を用いて行うことができる。θ1が各々上記関係を満たすことは、表示画像において高い輝度を得ること、光漏れを抑制または防止することに寄与でき、カラー液晶表示装置においては忠実な色再現を得ることに寄与できる。
<セルロースエステルフィルムの物性>
本発明のセルロースエステルフィルムの透湿度は、40℃、90%RHで300~1800g/m2・24hが好ましく、更に400~1500g/m2・24hが好ましく、40~1300g/m2・24hが特に好ましい。透湿度はJIS Z 0208に記載の方法に従い測定することができる。 This θ1 can be defined as an orientation angle, and the measurement of θ1 can be performed using an automatic birefringence meter KOBRA-21ADH (Oji Scientific Instruments). Each of θ1 satisfying the above relationship can contribute to obtaining high luminance in a display image, suppressing or preventing light leakage, and contributing to obtaining faithful color reproduction in a color liquid crystal display device.
<Physical properties of cellulose ester film>
The moisture permeability of the cellulose ester film of the present invention is preferably 300 to 1800 g / m 2 · 24 h at 40 ° C. and 90% RH, more preferably 400 to 1500 g / m 2 · 24 h, and 40 to 1300 g / m 2 · 24 h. Particularly preferred. The moisture permeability can be measured according to the method described in JIS Z 0208.
<セルロースエステルフィルムの物性>
本発明のセルロースエステルフィルムの透湿度は、40℃、90%RHで300~1800g/m2・24hが好ましく、更に400~1500g/m2・24hが好ましく、40~1300g/m2・24hが特に好ましい。透湿度はJIS Z 0208に記載の方法に従い測定することができる。 This θ1 can be defined as an orientation angle, and the measurement of θ1 can be performed using an automatic birefringence meter KOBRA-21ADH (Oji Scientific Instruments). Each of θ1 satisfying the above relationship can contribute to obtaining high luminance in a display image, suppressing or preventing light leakage, and contributing to obtaining faithful color reproduction in a color liquid crystal display device.
<Physical properties of cellulose ester film>
The moisture permeability of the cellulose ester film of the present invention is preferably 300 to 1800 g / m 2 · 24 h at 40 ° C. and 90% RH, more preferably 400 to 1500 g / m 2 · 24 h, and 40 to 1300 g / m 2 · 24 h. Particularly preferred. The moisture permeability can be measured according to the method described in JIS Z 0208.
本発明のセルロースエステルフィルムは破断伸度は10~80%であることが好ましく20~50%であることが更に好ましい。
The cellulose ester film of the present invention has a breaking elongation of preferably 10 to 80%, more preferably 20 to 50%.
本発明のセルロースエステルフィルムの可視光透過率は90%以上であることが好ましく、93%以上であることが更に好ましい。
The visible light transmittance of the cellulose ester film of the present invention is preferably 90% or more, and more preferably 93% or more.
本発明のセルロースエステルフィルムのヘイズは1%未満であることが好ましく0~0.1%であることが特に好ましい。
The haze of the cellulose ester film of the present invention is preferably less than 1%, particularly preferably 0 to 0.1%.
また、本発明のセルロースエステルフィルムにさらに液晶層を塗布することにより、さらに広い範囲にわたるレターデーション値を得ることが出来る。
<偏光板>
本発明のセルロースエステルフィルムは、偏光板、それを用いた液晶表示装置に使用することができる。 Further, by applying a liquid crystal layer to the cellulose ester film of the present invention, retardation values over a wider range can be obtained.
<Polarizing plate>
The cellulose ester film of the present invention can be used for a polarizing plate and a liquid crystal display device using the polarizing plate.
<偏光板>
本発明のセルロースエステルフィルムは、偏光板、それを用いた液晶表示装置に使用することができる。 Further, by applying a liquid crystal layer to the cellulose ester film of the present invention, retardation values over a wider range can be obtained.
<Polarizing plate>
The cellulose ester film of the present invention can be used for a polarizing plate and a liquid crystal display device using the polarizing plate.
本発明の偏光板は一般的な方法で作製することができる。本発明のセルロースエステルフィルムの偏光子側をアルカリ鹸化処理し、沃素溶液中に浸漬延伸して作製した偏光子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。
The polarizing plate of the present invention can be produced by a general method. The cellulose ester film of the present invention is preferably bonded to at least one surface of a polarizer produced by subjecting the polarizer side to alkali saponification treatment and immersion drawing in an iodine solution using a completely saponified polyvinyl alcohol aqueous solution.
本発明のT1、T4の偏光板保護フィルムとしては、例えば、市販のセルロースエステルフィルム(例えば、コニカミノルタタック KC8UX、KC5UX、KC8UCR3、KC8UCR4、KC8UCR5、KC8UY、KC4UY、KC4UE、KC8UE、KC8UY-HA、KC8UX-RHA、KC8UXW-RHA-C、KC8UXW-RHA-NC、KC4UXW-RHA-NC、以上コニカミノルタオプト(株)製)も好ましく用いられる。
Examples of the polarizing plate protective film for T1 and T4 of the present invention include a commercially available cellulose ester film (for example, Konica Minoltack KC8UX, KC5UX, KC8UCR3, KC8UCR4, KC8UCR5, KC8UY, KC4UY, KC4UE, KC8UE, KC8UY-X, -RHA, KC8UXW-RHA-C, KC8UXW-RHA-NC, KC4UXW-RHA-NC, manufactured by Konica Minolta Opto Co., Ltd.) are also preferably used.
表示装置の表面側に用いられる偏光板には、防眩層あるいはクリアハードコート層のほか、反射防止層、帯電防止層、防汚層、バックコート層を有することが好ましい。
The polarizing plate used on the surface side of the display device preferably has an antireflection layer, an antistatic layer, an antifouling layer, and a backcoat layer in addition to the antiglare layer or the clear hard coat layer.
偏光板の主たる構成要素である偏光子とは、一定方向の偏波面の光だけを通す素子であり、現在知られている代表的な偏光子は、ポリビニルアルコール系偏光フィルムで、これはポリビニルアルコール系フィルムにヨウ素を染色させたものと二色性染料を染色させたものがある。
A polarizer, which is a main component of a polarizing plate, is an element that allows only light of a plane of polarization in a certain direction to pass. A typical polarizer currently known is a polyvinyl alcohol-based polarizing film, which is polyvinyl alcohol. There are one in which iodine is dyed on a system film and one in which dichroic dye is dyed.
偏光子は、ポリビニルアルコール水溶液を製膜し、これを一軸延伸させて染色するか、染色した後一軸延伸してから、好ましくはホウ素化合物で耐久性処理を行ったものが用いられている。偏光子の膜厚は5~30μmが好ましく、特に10~20μmであることが好ましい。
The polarizer is formed by forming a polyvinyl alcohol aqueous solution into a film and dyeing the film by uniaxial stretching or dyeing or uniaxially stretching, and then performing a durability treatment with a boron compound. The film thickness of the polarizer is preferably 5 to 30 μm, particularly preferably 10 to 20 μm.
また、特開2003-248123号公報、特開2003-342322号公報等に記載のエチレン単位の含有量1~4モル%、重合度2000~4000、けん化度99.0~99.99モル%のエチレン変性ポリビニルアルコールも好ましく用いられる。
Further, the ethylene unit content described in JP-A-2003-248123, JP-A-2003-342322, etc. is 1 to 4 mol%, the degree of polymerization is 2000 to 4000, and the degree of saponification is 99.0 to 99.99 mol%. Ethylene-modified polyvinyl alcohol is also preferably used.
中でも熱水切断温度が66~73℃であるエチレン変性ポリビニルアルコールフィルムが好ましく用いられる。
Among them, an ethylene-modified polyvinyl alcohol film having a hot water cutting temperature of 66 to 73 ° C. is preferably used.
又、フィルムのTD方向に5cm離れた二点間の熱水切断温度の差が1℃以下であることが、色斑を低減させるうえで更に好ましく、更にフィルムのTD方向に1cm離れた二点間の熱水切断温度の差が0.5℃以下であることが、色斑を低減させるうえで更に好ましい。
The difference in hot water cutting temperature between two points 5 cm away in the TD direction of the film is more preferably 1 ° C. or less in order to reduce color spots, and two points separated 1 cm in the TD direction of the film. In order to reduce color spots, it is more preferable that the difference in the hot water cutting temperature is 0.5 ° C. or less.
このエチレン変性ポリビニルアルコールフィルムを用いた偏光子は、偏光性能および耐久性能に優れているうえに、色斑が少なく、大型液晶表示装置に特に好ましく用いられる。
A polarizer using this ethylene-modified polyvinyl alcohol film is excellent in polarization performance and durability performance and has few color spots, and is particularly preferably used for a large liquid crystal display device.
以上のようにして得られた偏光子は、通常、その両面または片面に保護フィルムが貼合されて偏光板として使用される。貼合する際に用いられる接着剤としては、PVA系の接着剤やウレタン系の接着剤などを挙げることができるが、中でもPVA系の接着剤が好ましく用いられる。本発明の偏光板は偏光板保護フィルムを用いることが好ましい。
<液晶表示装置>
本発明のセルロースエステルフィルムを、LCDバックライトを使用した液晶表示装置に用いることによって、視認性に優れた本発明の液晶表示装置とことができる。 The polarizer obtained as described above is usually used as a polarizing plate with a protective film bonded to both sides or one side thereof. Examples of the adhesive used for pasting include a PVA-based adhesive and a urethane-based adhesive. Among them, a PVA-based adhesive is preferably used. The polarizing plate of the present invention preferably uses a polarizing plate protective film.
<Liquid crystal display device>
By using the cellulose ester film of the present invention for a liquid crystal display device using an LCD backlight, the liquid crystal display device of the present invention having excellent visibility can be obtained.
<液晶表示装置>
本発明のセルロースエステルフィルムを、LCDバックライトを使用した液晶表示装置に用いることによって、視認性に優れた本発明の液晶表示装置とことができる。 The polarizer obtained as described above is usually used as a polarizing plate with a protective film bonded to both sides or one side thereof. Examples of the adhesive used for pasting include a PVA-based adhesive and a urethane-based adhesive. Among them, a PVA-based adhesive is preferably used. The polarizing plate of the present invention preferably uses a polarizing plate protective film.
<Liquid crystal display device>
By using the cellulose ester film of the present invention for a liquid crystal display device using an LCD backlight, the liquid crystal display device of the present invention having excellent visibility can be obtained.
一般的なLEDバックライトは、青色LEDと蛍光体を組み合わせることによって白色を再現している。疑似白色タイプと呼ばれるLEDは、480nm(青)付近と570nm(黄)付近の2ピークが観察され、高演色白色タイプと呼ばれるLEDは、青以外に、530nm(緑)付近、620nm(赤)付近の3ピークが観察される。しかしながら、冷陰極管とは、波長特性が異なることから白の再現は異なっている。
General LED backlight reproduces white color by combining blue LED and phosphor. The LED called the pseudo-white type has two peaks around 480 nm (blue) and 570 nm (yellow), and the LED called the high color rendering white type has 530 nm (green) and 620 nm (red) in addition to blue. 3 peaks are observed. However, since the wavelength characteristics are different from those of the cold cathode tube, white reproduction is different.
本発明では、特開2009-301010号明細書記載の垂直配向ECB型液晶表示装置であると効果が顕著となる。この液晶表示装置は、開口率が65%以上と高いため、偏光板の赤色変色がはっきり見えることとなるからである。
In the present invention, the effect becomes remarkable when it is a vertical alignment ECB type liquid crystal display device described in JP-A-2009-301010. This is because the liquid crystal display device has a high aperture ratio of 65% or more, so that the red color change of the polarizing plate can be clearly seen.
実施例1
<セルロースエステルフィルム101の作製>
〈微粒子分散液1〉
微粒子(アエロジル R972V 日本アエロジル(株)製)
11質量部
エタノール 89質量部
以上をディゾルバーで50分間攪拌混合した後、マントンゴーリンで分散を行った。 Example 1
<Production of Cellulose Ester Film 101>
<Fine particle dispersion 1>
Fine particles (Aerosil R972V manufactured by Nippon Aerosil Co., Ltd.)
11 parts by mass Ethanol 89 parts by mass The above was stirred and mixed with a dissolver for 50 minutes, and then dispersed with Manton Gorin.
<セルロースエステルフィルム101の作製>
〈微粒子分散液1〉
微粒子(アエロジル R972V 日本アエロジル(株)製)
11質量部
エタノール 89質量部
以上をディゾルバーで50分間攪拌混合した後、マントンゴーリンで分散を行った。 Example 1
<Production of Cellulose Ester Film 101>
<
Fine particles (Aerosil R972V manufactured by Nippon Aerosil Co., Ltd.)
11 parts by mass Ethanol 89 parts by mass The above was stirred and mixed with a dissolver for 50 minutes, and then dispersed with Manton Gorin.
〈微粒子添加液1〉
メチレンクロライドを入れた溶解タンクに十分攪拌しながら、微粒子分散液1をゆっくりと添加した。更に、二次粒子の粒径が所定の大きさとなるようにアトライターにて分散を行った。これを日本精線(株)製のファインメットNFで濾過し、微粒子添加液1を調製した。 <Fineparticle addition liquid 1>
Thefine particle dispersion 1 was slowly added to the dissolution tank containing methylene chloride with sufficient stirring. Further, the particles were dispersed by an attritor so that the secondary particles had a predetermined particle size. This was filtered through Finemet NF manufactured by Nippon Seisen Co., Ltd. to prepare a fine particle additive solution 1.
メチレンクロライドを入れた溶解タンクに十分攪拌しながら、微粒子分散液1をゆっくりと添加した。更に、二次粒子の粒径が所定の大きさとなるようにアトライターにて分散を行った。これを日本精線(株)製のファインメットNFで濾過し、微粒子添加液1を調製した。 <Fine
The
メチレンクロライド 99質量部
微粒子分散液1 5質量部
下記組成の主ドープ液を調製した。まず加圧溶解タンクにメチレンクロライドとエタノールを添加した。溶剤の入った加圧溶解タンクにセルロースアセテートCを攪拌しながら投入した。これを加熱し、攪拌しながら、完全に溶解し。これを安積濾紙(株)製の安積濾紙No.244を使用して濾過し、主ドープ液を調製した。 Methylene chloride 99 parts by massFine particle dispersion 1 5 parts by mass A main dope solution having the following composition was prepared. First, methylene chloride and ethanol were added to the pressure dissolution tank. Cellulose acetate C was charged into a pressure dissolution tank containing a solvent while stirring. This is completely dissolved with heating and stirring. This was designated as Azumi Filter Paper No. The main dope solution was prepared by filtration using 244.
微粒子分散液1 5質量部
下記組成の主ドープ液を調製した。まず加圧溶解タンクにメチレンクロライドとエタノールを添加した。溶剤の入った加圧溶解タンクにセルロースアセテートCを攪拌しながら投入した。これを加熱し、攪拌しながら、完全に溶解し。これを安積濾紙(株)製の安積濾紙No.244を使用して濾過し、主ドープ液を調製した。 Methylene chloride 99 parts by mass
〈主ドープ液の組成〉
メチレンクロライド 340質量部
エタノール 64質量部
セルロースジセテート(アセチル基置換度2.41) 100質量部
エステル化合物1-2 6.0質量部
エステル化合物2-16 6.0質量部
微粒子添加液1 1質量部
以上を密閉容器に投入し、攪拌しながら溶解してドープ液を調製した。次いで、無端ベルト流延装置を用い、ドープ液を温度33℃、1500mm幅でステンレスベルト支持体上に均一に流延した。ステンレスベルトの温度は30℃に制御した。 <Composition of main dope solution>
Methylene chloride 340 parts by weight Ethanol 64 parts by weight Cellulose discetate (acetyl group substitution degree 2.41) 100 parts by weight Ester compound 1-2 6.0 parts by weight Ester compound 2-16 6.0 parts by weight Particulateadditive liquid 1 1 part by weight The above was put into a closed container and dissolved while stirring to prepare a dope solution. Next, using an endless belt casting apparatus, the dope solution was uniformly cast on a stainless steel belt support at a temperature of 33 ° C. and a width of 1500 mm. The temperature of the stainless steel belt was controlled at 30 ° C.
メチレンクロライド 340質量部
エタノール 64質量部
セルロースジセテート(アセチル基置換度2.41) 100質量部
エステル化合物1-2 6.0質量部
エステル化合物2-16 6.0質量部
微粒子添加液1 1質量部
以上を密閉容器に投入し、攪拌しながら溶解してドープ液を調製した。次いで、無端ベルト流延装置を用い、ドープ液を温度33℃、1500mm幅でステンレスベルト支持体上に均一に流延した。ステンレスベルトの温度は30℃に制御した。 <Composition of main dope solution>
Methylene chloride 340 parts by weight Ethanol 64 parts by weight Cellulose discetate (acetyl group substitution degree 2.41) 100 parts by weight Ester compound 1-2 6.0 parts by weight Ester compound 2-16 6.0 parts by weight Particulate
ステンレスベルト支持体上で、流延(キャスト)したフィルム中の残留溶媒量が75%になるまで溶媒を蒸発させ、次いで剥離張力130N/mで、ステンレスベルト支持体上から剥離した。
On the stainless steel belt support, the solvent was evaporated until the amount of residual solvent in the cast (cast) film reached 75%, and then peeled off from the stainless steel belt support with a peeling tension of 130 N / m.
剥離したセルロースアセテートフィルムを、160℃の熱をかけながらテンターを用いて幅方向に36%延伸した。延伸開始時の残留溶媒は15%であった。
The peeled cellulose acetate film was stretched 36% in the width direction using a tenter while applying heat at 160 ° C. The residual solvent at the start of stretching was 15%.
次いで、乾燥ゾーンを多数のロールで搬送させながら乾燥を終了させた。乾燥温度は130℃で、搬送張力は100N/mとした。以上のようにして、乾燥膜厚40μmのセルロースエステルフィルム101を得た。
<セルロースエステルフィルム102~302の作製>
ドープ構成物を表に示すように変更した以外は、セルロースエステルフィルム101と同様にしてセルロースエステルフィルム102~302を作製した。
<偏光板の作製>
厚さ、75μmのポリビニルアルコールフィルムを、35℃の水で膨潤させこれをヨウ素0.075g、ヨウ化カリウム5g、水100gからなる水溶液に60秒間浸漬し、次いでヨウ化カリウム3g、ホウ酸7.5g、水100gからなる45℃の水溶液に浸漬し一軸延伸(温度55℃、延伸倍率5倍)した。これを水洗、乾燥し偏光子を得た。 Next, drying was terminated while the drying zone was conveyed by a number of rolls. The drying temperature was 130 ° C. and the transport tension was 100 N / m. As described above, a cellulose ester film 101 having a dry film thickness of 40 μm was obtained.
<Preparation of cellulose ester films 102-302>
Cellulose ester films 102 to 302 were produced in the same manner as the cellulose ester film 101 except that the dope composition was changed as shown in the table.
<Preparation of polarizing plate>
A polyvinyl alcohol film having a thickness of 75 μm was swollen with water at 35 ° C. and immersed in an aqueous solution consisting of 0.075 g of iodine, 5 g of potassium iodide, and 100 g of water, and then 3 g of potassium iodide and 7. It was immersed in a 45 ° C. aqueous solution consisting of 5 g and 100 g of water and uniaxially stretched (temperature 55 ° C., stretch ratio 5 times). This was washed with water and dried to obtain a polarizer.
<セルロースエステルフィルム102~302の作製>
ドープ構成物を表に示すように変更した以外は、セルロースエステルフィルム101と同様にしてセルロースエステルフィルム102~302を作製した。
<偏光板の作製>
厚さ、75μmのポリビニルアルコールフィルムを、35℃の水で膨潤させこれをヨウ素0.075g、ヨウ化カリウム5g、水100gからなる水溶液に60秒間浸漬し、次いでヨウ化カリウム3g、ホウ酸7.5g、水100gからなる45℃の水溶液に浸漬し一軸延伸(温度55℃、延伸倍率5倍)した。これを水洗、乾燥し偏光子を得た。 Next, drying was terminated while the drying zone was conveyed by a number of rolls. The drying temperature was 130 ° C. and the transport tension was 100 N / m. As described above, a cellulose ester film 101 having a dry film thickness of 40 μm was obtained.
<Preparation of cellulose ester films 102-302>
Cellulose ester films 102 to 302 were produced in the same manner as the cellulose ester film 101 except that the dope composition was changed as shown in the table.
<Preparation of polarizing plate>
A polyvinyl alcohol film having a thickness of 75 μm was swollen with water at 35 ° C. and immersed in an aqueous solution consisting of 0.075 g of iodine, 5 g of potassium iodide, and 100 g of water, and then 3 g of potassium iodide and 7. It was immersed in a 45 ° C. aqueous solution consisting of 5 g and 100 g of water and uniaxially stretched (temperature 55 ° C., stretch ratio 5 times). This was washed with water and dried to obtain a polarizer.
次いで、下記工程1~5に従って偏光子と前記セルロースアセテートフィルムと、裏面側にはコニカミノルタタックKC4UY(コニカミノルタオプト(株)製セルローストリアセテートフィルム、アセチル基置換度2.90)を貼り合わせて偏光板を作製した。
Next, a polarizer, the cellulose acetate film, and Konica Minolta Tack KC4UY (a cellulose triacetate film manufactured by Konica Minolta Opto Co., Ltd., acetyl group substitution degree 2.90) are bonded to the back side in accordance with the following steps 1 to 5. A plate was made.
工程1:60℃の2モル/Lの水酸化ナトリウム溶液に90秒間浸漬し、次いで水洗し乾燥して、偏光子と貼合する側を鹸化したセルロースアセテートフィルムを得た。
Step 1: Soaked in a 2 mol / L sodium hydroxide solution at 60 ° C. for 90 seconds, then washed with water and dried to obtain a saponified cellulose acetate film on the side to be bonded to the polarizer.
工程2:前記偏光子を固形分2質量%のポリビニルアルコール接着剤槽中に1~2秒浸漬した。
Step 2: The polarizer was immersed in a polyvinyl alcohol adhesive tank having a solid content of 2% by mass for 1 to 2 seconds.
工程3:工程2で偏光子に付着した過剰の接着剤を軽く拭き除き、これを工程1で処理したセルロースエステルフィルムの上にのせて配置した。
Step 3: Excess adhesive adhered to the polarizer in Step 2 was gently wiped off and placed on the cellulose ester film treated in Step 1.
工程4:工程3で積層したセルロースエステルフィルムと偏光子と裏面側セルロースエステルフィルムを圧力20~30N/cm2、搬送スピードは約2m/分で貼合した。
Step 4: The cellulose ester film, the polarizer and the back side cellulose ester film laminated in Step 3 were bonded at a pressure of 20 to 30 N / cm 2 and a conveying speed of about 2 m / min.
工程5:80℃の乾燥機中に工程4で作製した偏光子とセルロースエステルフィルムとコニカミノルタタックKC4UYとを貼り合わせた試料を2分間乾燥し、それぞれ、セルロースエステルフィルムに対応する偏光板を作製した。
Step 5: A sample obtained by bonding the polarizer, the cellulose ester film, and Konica Minoltack KC4UY prepared in Step 4 in a dryer at 80 ° C. is dried for 2 minutes, and a polarizing plate corresponding to the cellulose ester film is prepared. did.
表1中、COPとは、日本ゼオン(株)製ゼオノアフィルムZF14-060を意味し、偏光子との貼合は、コロナ放電処理し、あとは同様にして偏光板を作製した。
In Table 1, COP means ZEONOR film ZF14-060 manufactured by Nippon Zeon Co., Ltd., and bonding with a polarizer was subjected to corona discharge treatment, and thereafter a polarizing plate was produced in the same manner.
<液晶表示装置の作製>
SONY製40型ディスプレイBRAVIA-KDL-40EX700(開口率53%)の予め貼合されていた両面の偏光板を剥がして、上記作製した偏光板をそれぞれ液晶セルのガラス面の両面に貼合した。 <Production of liquid crystal display device>
The double-sided polarizing plates of the Sony 40-type display BRAVIA-KDL-40EX700 (opening ratio 53%) were peeled off, and the prepared polarizing plates were bonded to both glass surfaces of the liquid crystal cell, respectively.
SONY製40型ディスプレイBRAVIA-KDL-40EX700(開口率53%)の予め貼合されていた両面の偏光板を剥がして、上記作製した偏光板をそれぞれ液晶セルのガラス面の両面に貼合した。 <Production of liquid crystal display device>
The double-sided polarizing plates of the Sony 40-type display BRAVIA-KDL-40EX700 (opening ratio 53%) were peeled off, and the prepared polarizing plates were bonded to both glass surfaces of the liquid crystal cell, respectively.
また、上記液晶ディスプレイのLEDバックライトユニットを、特開2009-301010号明細書図18に記載の液晶セル(開口率67%)を使用した液晶表示装置に転用し液晶表示装置を作製し、同様に偏光板を貼合した。
Further, the above-described LED backlight unit of the liquid crystal display is diverted to a liquid crystal display device using a liquid crystal cell (opening ratio: 67%) described in FIG. 18 of JP2009-301010A to produce a liquid crystal display device. A polarizing plate was bonded to the substrate.
これらの液晶表示装置について、下記の評価を行った。
These liquid crystal display devices were evaluated as follows.
液晶表示装置を23℃55%RHで24時間調湿してから白の画像を表示し、正面の色味を目視および透過スペクトル観察(コニカミノルタセンシング(株)製CS2000)した。その結果、貼合した偏光板の正面の目視色味は同じであった。また、透過スペクトルにも、差が認められなかった。
The liquid crystal display device was conditioned at 23 ° C. and 55% RH for 24 hours, and then a white image was displayed. The front color was visually observed and the transmission spectrum was observed (CS2000 manufactured by Konica Minolta Sensing Co., Ltd.). As a result, the visual tint on the front of the bonded polarizing plate was the same. In addition, no difference was observed in the transmission spectrum.
液晶表示装置を23℃95%RHで48時間置いた。それを取り出して白の画像を表示し、23℃55%RHの雰囲気下で同様に観察した。観察結果を表3に示す。
〈赤色画像評価レベル〉
5 目視では白く、550nmに対する650nmの透過率変化が1%未満
4 目視では白く、550nmに対する650nmの変化が1%~3%未満
3 目視では微妙にピンクがかっており、550nmに対する650nmの変化が1%~3%未満
2 目視ではピンクがかっており、550nmに対する650nmの変化が1%~3%未満
1 目視ではっきりと赤みが認識でき、550nmに対する650nmの透過率変化が3%以上 The liquid crystal display device was placed at 23 ° C. and 95% RH for 48 hours. It was taken out and a white image was displayed, which was similarly observed in an atmosphere of 23 ° C. and 55% RH. The observation results are shown in Table 3.
<Red image evaluation level>
5 Visually white, 650 nm transmittance change to 550 nm is less than 1% 4 Visually white, 650 nm change to 550 nm is 1% to less than 3% 3 Visually slightly pinkish, 650 nm change to 550 nm is 1 % To less than 3% 2 Visually pinkish, change at 650 nm with respect to 550 nm is less than 1% to less than 3% 1 The redness can be clearly recognized visually, and the change in transmittance at 650 nm with respect to 550 nm is 3% or more
〈赤色画像評価レベル〉
5 目視では白く、550nmに対する650nmの透過率変化が1%未満
4 目視では白く、550nmに対する650nmの変化が1%~3%未満
3 目視では微妙にピンクがかっており、550nmに対する650nmの変化が1%~3%未満
2 目視ではピンクがかっており、550nmに対する650nmの変化が1%~3%未満
1 目視ではっきりと赤みが認識でき、550nmに対する650nmの透過率変化が3%以上 The liquid crystal display device was placed at 23 ° C. and 95% RH for 48 hours. It was taken out and a white image was displayed, which was similarly observed in an atmosphere of 23 ° C. and 55% RH. The observation results are shown in Table 3.
<Red image evaluation level>
5 Visually white, 650 nm transmittance change to 550 nm is less than 1% 4 Visually white, 650 nm change to 550 nm is 1% to less than 3% 3 Visually slightly pinkish, 650 nm change to 550 nm is 1 % To less than 3% 2 Visually pinkish, change at 650 nm with respect to 550 nm is less than 1% to less than 3% 1 The redness can be clearly recognized visually, and the change in transmittance at 650 nm with respect to 550 nm is 3% or more
赤味が強くなっている部分の透過スペクトルでは、赤の領域の透過率が上がっており、赤変する結果および仮説を支持する結果となった。
In the transmission spectrum of the part where the redness is strong, the transmittance of the red region is increased, and the result of red change and the result supporting the hypothesis.
1 視認側偏光板
T1 視認側偏光板の視認側偏光板保護フィルム
T2 視認側偏光板の液晶セル側偏光板保護フィルム
CE 液晶セル
2 バックライト側偏光板
T3 バックライト側偏光板の液晶セル側偏光板保護フィルム
T4 バックライト側偏光板のバックライト側偏光板保護フィルム
BL LEDバックライト
3、4 偏光子 1 viewing side polarizing plate T1 viewing side polarizing plate protective film of viewing side polarizing plate T2 liquid crystal cell side polarizing plate protective film of viewing side polarizing plate CEliquid crystal cell 2 backlight side polarizing plate T3 liquid crystal cell side polarizing of backlight side polarizing plate Plate protective film T4 Backlight side polarizing plate protective film of backlight side polarizing plate BL LED backlight 3, 4 Polarizer
T1 視認側偏光板の視認側偏光板保護フィルム
T2 視認側偏光板の液晶セル側偏光板保護フィルム
CE 液晶セル
2 バックライト側偏光板
T3 バックライト側偏光板の液晶セル側偏光板保護フィルム
T4 バックライト側偏光板のバックライト側偏光板保護フィルム
BL LEDバックライト
3、4 偏光子 1 viewing side polarizing plate T1 viewing side polarizing plate protective film of viewing side polarizing plate T2 liquid crystal cell side polarizing plate protective film of viewing side polarizing plate CE
Claims (3)
- 2枚の偏光板保護フィルムで挟まれた構造を有する視認側偏光板、液晶セル、2枚の偏光板保護フィルムで挟まれた構造を有するバックライト側偏光板、およびLEDバックライトを、視認側からこの順で有する液晶表示装置において、該視認側偏光板の2枚の偏光板保護フィルムがいずれもセルロースエステルフィルムであり、かつ該バックライト側偏光板の液晶セル側の偏光板保護フィルムがセルロースエステルフィルムであることを特徴とする液晶表示装置。 A viewing side polarizing plate having a structure sandwiched between two polarizing plate protective films, a liquid crystal cell, a backlight side polarizing plate having a structure sandwiched between two polarizing plate protective films, and an LED backlight on the viewing side In this order, the two polarizing plate protective films of the viewing side polarizing plate are both cellulose ester films, and the polarizing plate protective film on the liquid crystal cell side of the backlight side polarizing plate is cellulose. A liquid crystal display device characterized by being an ester film.
- 前記視認側偏光板であって液晶セル側の偏光板保護フィルムが、アセチル基置換度Xが2.10≦X<2.50のセルロースアセテートフィルムであることを特徴とする請求項1記載の液晶表示装置。 2. The liquid crystal according to claim 1, wherein the polarizing plate protective film on the viewing side polarizing plate is a cellulose acetate film having an acetyl group substitution degree X of 2.10 ≦ X <2.50. Display device.
- 前記液晶表示装置の開口率が、65%以上であることを特徴とする請求項1または2記載の液晶表示装置。 The liquid crystal display device according to claim 1 or 2, wherein an aperture ratio of the liquid crystal display device is 65% or more.
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WO2012140990A1 (en) * | 2011-04-12 | 2012-10-18 | コニカミノルタアドバンストレイヤー株式会社 | Optical compensation film and process for producing same, polarizing plate, and liquid crystal display device |
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JP2009001744A (en) * | 2007-06-25 | 2009-01-08 | Konica Minolta Opto Inc | Cellulose ester film, method for producing cellulose ester film, and polarizing plate and liquid crystal display device using the same |
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JP2007080735A (en) * | 2005-09-15 | 2007-03-29 | Nec Corp | Light source device and its manufacturing method, indicator device and its manufacturing method, and drive method for indicator device |
JP2009001744A (en) * | 2007-06-25 | 2009-01-08 | Konica Minolta Opto Inc | Cellulose ester film, method for producing cellulose ester film, and polarizing plate and liquid crystal display device using the same |
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WO2012140990A1 (en) * | 2011-04-12 | 2012-10-18 | コニカミノルタアドバンストレイヤー株式会社 | Optical compensation film and process for producing same, polarizing plate, and liquid crystal display device |
CN107302665A (en) * | 2017-08-18 | 2017-10-27 | 联想(北京)有限公司 | A kind of camera device, aperture regulating method and electronic equipment |
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