WO2012124514A1 - セルロースエステルフィルム、それが具備された偏光板及び液晶表示装置 - Google Patents
セルロースエステルフィルム、それが具備された偏光板及び液晶表示装置 Download PDFInfo
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- G02B5/32—Holograms used as optical elements
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- C08K5/00—Use of organic ingredients
- C08K5/04—Oxygen-containing compounds
- C08K5/10—Esters; Ether-esters
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- C08K5/00—Use of organic ingredients
- C08K5/04—Oxygen-containing compounds
- C08K5/15—Heterocyclic compounds having oxygen in the ring
- C08K5/151—Heterocyclic compounds having oxygen in the ring having one oxygen atom in the ring
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- C08L1/00—Compositions of cellulose, modified cellulose or cellulose derivatives
- C08L1/08—Cellulose derivatives
- C08L1/10—Esters of organic acids, i.e. acylates
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- C08L1/00—Compositions of cellulose, modified cellulose or cellulose derivatives
- C08L1/08—Cellulose derivatives
- C08L1/10—Esters of organic acids, i.e. acylates
- C08L1/14—Mixed esters, e.g. cellulose acetate-butyrate
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- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers
- C08L67/02—Polyesters derived from dicarboxylic acids and dihydroxy compounds
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- G—PHYSICS
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- G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
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- G02B1/14—Protective coatings, e.g. hard coatings
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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
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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
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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
- G02F1/13363—Birefringent elements, e.g. for optical compensation
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2457/00—Electrical equipment
- B32B2457/20—Displays, e.g. liquid crystal displays, plasma displays
- B32B2457/202—LCD, i.e. liquid crystal displays
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2301/00—Characterised by the use of cellulose, modified cellulose or cellulose derivatives
- C08J2301/08—Cellulose derivatives
- C08J2301/10—Esters of organic acids
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2301/00—Characterised by the use of cellulose, modified cellulose or cellulose derivatives
- C08J2301/08—Cellulose derivatives
- C08J2301/14—Mixed esters
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K2323/00—Functional layers of liquid crystal optical display excluding electroactive liquid crystal layer characterised by chemical composition
- C09K2323/03—Viewing layer characterised by chemical composition
- C09K2323/035—Ester polymer, e.g. polycarbonate, polyacrylate or polyester
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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
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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
Definitions
- the present invention relates to a cellulose ester film, a polarizing plate provided with the cellulose ester film, and a liquid crystal display device. More specifically, the present invention relates to a cellulose ester film having a high transmittance, a polarizing plate that is provided with the cellulose ester film and has little deterioration during durability, and a liquid crystal display device having a high contrast.
- liquid crystal display devices have been widely used because they are thin, lightweight, and have low power consumption.
- labor saving and thinning of members have been promoted.
- For both low power consumption and 3D it is necessary to increase the light utilization efficiency.
- the present invention has been made in view of the above problems and situations, and a problem to be solved is to provide a cellulose ester film having a high transmittance and a method for producing the same. It is another object of the present invention to provide a polarizing plate and a high contrast liquid crystal display device which are provided with the cellulose ester film and have little deterioration during durability.
- a cellulose ester having a weight average molecular weight of 150,000 or less, and at least one saccharide unit structure of at least one of a pyranose structure or a furanose structure, and an average substitution ratio in the saccharide unit structure is A cellulose ester film comprising a sugar ester compound in an amount of 35% to 75%, and further having a thickness of 10 to 35 ⁇ m.
- the sugar ester compound is a compound represented by the following general formula (1):
- the in-plane retardation value Ro (590) of the cellulose ester film is in the range of 40 to 70 nm, the retardation value Rt (590) in the thickness direction is in the range of 100 to 200 nm, and the film contrast is 7000 to 6.
- a polarizing plate comprising the cellulose ester film according to any one of 1 to 6 above.
- a liquid crystal display device comprising the cellulose ester film according to any one of 1 to 6 above.
- the above-described means of the present invention can provide a cellulose ester film having a high transmittance and a method for producing the same.
- a polarizing plate and a high-contrast liquid crystal display device that are provided with the cellulose ester film and have little deterioration during durability can be provided.
- the cellulose ester film of the present invention is substituted with an acyl group having 3 to 4 carbon atoms, or an acyl group having 2 carbon atoms and an acyl group having 3 to 4 carbon atoms, and the acyl group substitution degree (total substitution degree) Having at least 1.0 and less than 2.0, having a weight average molecular weight of 150,000 or less, cellulose ester, and having at least one sugar unit structure of pyranose structure or furanose structure of 1 or more and 12 or less, and And a sugar ester compound having an average substitution rate of 35% to 75% in the sugar unit structure, and further having a film thickness of 10 to 35 ⁇ m.
- This feature is a technical feature common to the inventions according to claims 1 to 8.
- the total carbon number of an acyl substituent exceeds 4.4, and the substitution degree of an acyl group having 3 or more carbon atoms is 0.9 or more and less than 2.0.
- nx is the refractive index in the direction in which the in-plane refractive index is maximum (ie, the slow axis direction), and “ny” is the direction perpendicular to the slow axis in the plane (ie, advance). “Nz” is the refractive index in the thickness direction.
- Retardation (phase difference) Ro in the in-plane direction refers to the in-plane retardation value measured with light having a wavelength of 590 nm at 23 ° C. and 55% RH.
- the refractive index in the slow axis direction and the fast axis direction of the film (layer) at a wavelength of 590 nm is nx and ny and d (nm) is the thickness of the film (layer)
- Thickness direction retardation (phase difference) Rt refers to a thickness direction retardation value measured with light of a wavelength of 590 nm at 23 ° C. and 55% RH.
- the cellulose ester film of the present invention is a film having a high mechanical strength, being a thin film, having both a retardation and a transmittance, as compared with a conventional cellulose ester film.
- the cellulose ester film of the present invention is substituted with an acyl group having 3 to 4 carbon atoms, or an acyl group having 2 carbon atoms and an acyl group having 3 to 4 carbon atoms, and the acyl group substitution degree (total substitution degree) Is required to contain a cellulose ester having a weight average molecular weight (Mw) of 150,000 or less.
- the cellulose ester preferably has a substitution degree of an acyl group having 3 or more carbon atoms of 0.9 or more and less than 2.0.
- the cellulose ester preferably contains a cellulose ester in which the total carbon number of the acyl group exceeds 4.4.
- the acyl group having 2 to 4 carbon atoms include an acetyl group, a propionyl group, and a butanoyl group.
- the ⁇ -1,4-bonded glucose unit constituting cellulose has free hydroxyl groups (hydroxyl groups) at the 2nd, 3rd and 6th positions.
- the cellulose ester is a polymer obtained by acylating part or all of these hydroxyl groups (hydroxyl groups) with an acyl group.
- the total acyl group substitution degree is the ratio in which all of the hydroxyl groups (hydroxyl groups) of cellulose located at the 2-position, 3-position and 6-position are acylated per glucose unit (100% acylation has a substitution degree of 3). Means.
- the method for measuring the substitution degree of the acyl group can be carried out in accordance with ASTM D-817-91.
- the acyl group substitution degree (total substitution degree) is preferably 1.1 to 1.9, and more preferably 1.2 to 1.8. Further, the substitution degree of the acyl group having 3 or more carbon atoms is preferably 1.0 to 1.9, and more preferably 1.4 to 1.8.
- Such ultra-low-substituted cellulose ester is said to be easily deteriorated in surface quality and increased in haze due to stretching. This is likely to occur in the case of substitution only with an acetyl group, and an acyl group having 3 or more carbon atoms. It was found that this is not the case for the cellulose ester substituted with. That is, in the present invention, the cellulose ester is substituted with an acyl group having 3 to 4 carbon atoms, or an acyl group having 2 carbon atoms and an acyl group having 3 to 4 carbon atoms.
- the cellulose ester can have the following acyl group, and may be an aliphatic group or an aryl group, and is not particularly limited.
- acyl groups include acetyl, propionyl, butanoyl, heptanoyl, hexanoyl, octanoyl, decanoyl, dodecanoyl, tridecanoyl, tetradecanoyl, hexadecanoyl, octadecanoyl, Examples thereof include an isobutanoyl group, a tert-butanoyl group, a cyclohexanecarbonyl group, an oleoyl group, a benzoyl group, a naphthylcarbonyl group, and a cinnamoyl group.
- an acetyl group, a propionyl group, a butanoyl group, a dodecanoyl group, an octadecanoyl group, a tert-butanoyl group, an oleoyl group, a benzoyl group, a naphthylcarbonyl group, a cinnamoyl group, and the like are more preferable, and an acetyl group is particularly preferable.
- a propionyl group and a butanoyl group (when the acyl group has 2 to 4 carbon atoms);
- an organic acid such as acetic acid or methylene chloride is used as an organic solvent as a reaction solvent.
- the catalyst when the acylating agent is an acid anhydride, a protic catalyst such as sulfuric acid is preferably used, and when the acylating agent is an acid chloride (for example, CH 3 CH 2 COCl), Basic compounds are used.
- the weight average molecular weight (Mw) of the cellulose ester used in the present invention is preferably in the range of 50,000 to 150,000, and more preferably 100,000 to 150,000. It has been found that the cellulose ester having such a molecular weight has a high transmittance when formed into a film.
- the ratio Mw / Mn of the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the cellulose ester is preferably 1.4 to 3.0.
- the number average molecular weight (Mn) and weight average molecular weight (Mw) of the cellulose ester were measured using gel permeation chromatography (GPC).
- the measurement conditions are as follows.
- the most common industrial synthesis method of mixed fatty acid esters of cellulose is cellulose mixed organics containing fatty acids corresponding to acetyl groups and other acyl groups (acetic acid, propionic acid, valeric acid, etc.) or acid anhydrides thereof. This is a method of acylating with an acid component.
- the cellulose ester used in the present invention can be synthesized, for example, by the method described in JP-A-10-45804.
- a sugar ester compound having at least one sugar unit structure of at least one pyranose structure or furanose structure and having one or more hydroxyl groups in the sugar unit structure esterified It is simply called “sugar ester compound”.
- the average substitution ratio in the sugar unit structure is 35% to 75%.
- the average substitution rate is 35% to 65%.
- the “average substitution ratio in the saccharide unit structure” represents the ratio of the saccharide unit structure, ie, the 3-5 hydroxyl groups in the pyranose structure or furanose structure, which are substituted with a substituent other than the hydroxyl group. .
- glucose having a pyranose structure has four hydroxyl groups, but when all the hydroxyl groups of glucose are substituted, the substitution rate is 100%.
- sugar unit structure examples include erythrose, threorose, lyxose, xylose, arabinose, ribose, glucose, galactose, mannose, fructose, gulose, idose, talose, altrose, allose, and the like.
- erythrose and threorose have three hydroxyl groups in the unit structure
- lyxose, xylose, arabinose and ribose have four hydroxyl groups in the unit structure
- glucose, mannose, fructose, Growth, idose, galactose, talose, altrose, and allose have five hydroxyl groups in the unit structure.
- sugar as a raw material for the synthesis of the sugar ester compound examples include, for example, lactose, sucrose, kestose, nystose, 1F-fructosylnystose, stachyose, maltitol, lactitol, lactulose, cellobiose, Examples include maltose, cellotriose, maltotriose, raffinose, and kestose.
- gentiobiose, gentiotriose, gentiotetraose, xylotriose, galactosyl sucrose, and the like are also included. However, it is not limited to these.
- sugar ester compound a compound having both a pyranose structure and a furanose structure is preferable.
- examples include sucrose, kestose, nystose, 1F-fructosyl nystose, stachyose, and more preferably sucrose from the viewpoint of compatibility and volatility.
- the monocarboxylic acid used in the synthesis of the sugar ester compound according to the present invention known aliphatic monocarboxylic acid, alicyclic monocarboxylic acid, aromatic monocarboxylic acid and the like can be used.
- the carboxylic acid used may be one type or a mixture of two or more types.
- Examples of preferred aliphatic monocarboxylic acids include acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, 2-ethyl-hexanecarboxylic acid, undecyl acid, Saturated lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, heptacosanoic acid, montanic acid, mellicic acid, and laxaric acid
- unsaturated fatty acids such as fatty acids, undecylenic acid, oleic acid, sorbic acid, linoleic acid, linolenic acid, arachidonic acid and oc
- Examples of preferable alicyclic monocarboxylic acids include cyclopentane carboxylic acid, cyclohexane carboxylic acid, cyclooctane carboxylic acid, and derivatives thereof.
- aromatic monocarboxylic acids examples include aromatic monocarboxylic acids, cinnamic acids, in which 1 to 5 alkyl groups or alkoxy groups are introduced into the benzene ring of benzoic acid such as benzoic acid, phenylacetic acid, toluic acid, and the like.
- aromatic monocarboxylic acids having two or more benzene rings such as benzylic acid, biphenylcarboxylic acid, naphthalenecarboxylic acid, tetralincarboxylic acid, or derivatives thereof, and benzoic acid is particularly preferable.
- the degree of substitution of the compound represented by the general formula (1) represents the number of substituents other than hydrogen among the eight hydroxyl groups contained in the sucrose structure, that is, the general formula ( Of R 1 to R 8 in 1), this represents the number of groups other than hydrogen. Accordingly, when all of R 1 to R 8 are substituted with a substituent other than hydrogen, the degree of substitution is 8.0, the maximum value, and when all of R 1 to R 8 are hydrogen atoms, 0.0 It becomes.
- the degree of substitution of the compound represented by the general formula (1) is preferably 2.8 to 6.0. Further, 2.8 to 5.2 is more preferable.
- substitution degree of the general formula (1) it is appropriate to use the average substitution degree.
- the average substitution degree is calculated from the area ratio of the chart showing the substitution degree distribution by high performance liquid chromatography by the following method. Can be measured.
- the cellulose ester having a very low degree of substitution as in the present invention has many residual hydroxyl groups, the water resistance is more a concern than existing cellulose esters having a high degree of substitution.
- a plasticizer may be added, but if it is not compatible, it will volatilize. Based on the above, it has been found that the above-described object can be achieved by adding a sugar ester compound having a structure similar to that of cellulose ester and having a low degree of substitution. Bleed out can be suppressed by adding a sugar ester compound having a structure similar to that of cellulose ester and having a low degree of substitution.
- the ultra-low-substituted cellulose ester is susceptible to moisture, so there is a significant problem of shrinkage during durability when it is made into a polarizing plate. Therefore, by reducing the degree of substitution of the sugar ester compound, leaving many hydroxyl groups, and softening the hydrogen bonds between the low-substituted cellulose ester and the sugar ester compound, the effect of shrinkage on the polarizing plate can be reduced. Thought.
- the sugar ester compound is preferably a mixture having different degrees of substitution.
- R 1 to R 8 represent a substituted or unsubstituted alkylcarbonyl group or a substituted or unsubstituted allylcarbonyl group, that is, an acyl group, and R 1 to R 8 are the same. Or may be different (hereinafter, R 1 to R 8 are also referred to as acyl groups). Specific examples of R 1 to R 8 include acyl groups derived from monocarboxylic acids used during the synthesis of the sugar ester compounds exemplified above.
- R 1 to R 8 are all the same substituent R, but the present invention is not limited thereto, and R 1 to R 8 May be different groups.
- the sugar ester compound of the present invention can be produced by reacting a sugar compound with an acylating agent (also referred to as an esterifying agent, for example, an acid halide such as acetyl chloride or an anhydride such as acetic anhydride).
- an acylating agent also referred to as an esterifying agent, for example, an acid halide such as acetyl chloride or an anhydride such as acetic anhydride.
- the distribution of the esterification rate is made by adjusting the amount of acylating agent, the timing of addition, and the esterification reaction time.
- the target sugar ester compound can be produced by mixing different compounds.
- the inside of the Kolben was depressurized to 4 ⁇ 10 2 Pa or less, and after excess pyridine was distilled off at 60 ° C., the inside of the Kolben was depressurized to 1.3 ⁇ 10 Pa or less and the temperature was raised to 120 ° C. Most of the acid and benzoic acid formed were distilled off. Then, 1 L of toluene and 300 g of a 0.5% by mass aqueous sodium carbonate solution were added, and the mixture was stirred at 50 ° C. for 30 minutes and then allowed to stand to separate a toluene layer.
- the obtained mixture was analyzed by high performance liquid chromatography-mass spectrometry (HPLC-MS). As a result, A-1 was 1.2% by mass, A-2 was 13.2% by mass, and A-3 was 14.2% by mass. %, A-4 was 35.4% by mass, A-5 and the like were 40.0% by mass. The average degree of substitution was 5.2.
- A-5 etc. means a mixture of all components having a substitution degree of 4 or less, that is, compounds having substitution degrees of 4, 3, 2, 1.
- the average degree of substitution was calculated with A-5 and the like being the degree of substitution 4.
- the average degree of substitution was adjusted by adding in combination the sugar ester close to the desired degree of average substitution and the isolated A-1 to A-5 etc. by the method prepared here.
- the retardation adjusting agent is not particularly limited, and when additives such as a plasticizer, an ultraviolet absorber, an antioxidant, and a matting agent are also used as the retardation adjusting agent, these additives are used in the present invention. Included in modifier.
- Retardation expression agent in this invention, in order to express a retardation value, what consists of a rod-shaped or a disk shaped compound can be mentioned.
- a compound having at least two aromatic rings can be preferably used as a retardation developer.
- the addition amount of the retardation developer composed of the rod-like compound is preferably 0.1 to 30 parts by mass, and 0.5 to 20 parts by mass with respect to 100 parts by mass of the polymer (cellulose ester) component containing cellulose acylate. More preferably, it is a part.
- the disk-like retardation developer is preferably used in the range of 0.05 to 20 parts by mass, and in the range of 1.0 to 15 parts by mass with respect to 100 parts by mass of the polymer component containing cellulose acylate. It is more preferable to use in the range of 3.0 to 10 parts by mass.
- the discotic compound is superior to the rod-shaped compound in terms of Rt retardation expression, it is preferably used when a particularly large Rt retardation is required. Two or more types of retardation developing agents may be used in combination.
- the retardation developer preferably has a maximum absorption in the wavelength region of 250 to 400 nm, and preferably has substantially no absorption in the visible region.
- the discotic compound will be described.
- As the discotic compound a compound having at least two aromatic rings can be used.
- aromatic ring includes an aromatic heterocycle in addition to an aromatic hydrocarbon ring.
- the aromatic hydrocarbon ring is particularly preferably a 6-membered ring (that is, a benzene ring).
- the aromatic heterocycle is generally an unsaturated heterocycle.
- the aromatic heterocycle is preferably a 5-membered ring, 6-membered ring or 7-membered ring, more preferably a 5-membered ring or 6-membered ring.
- Aromatic heterocycles generally have the most double bonds.
- a nitrogen atom, an oxygen atom and a sulfur atom are preferable, and a nitrogen atom is particularly preferable.
- aromatic heterocycles include furan ring, thiophene ring, pyrrole ring, oxazole ring, isoxazole ring, thiazole ring, isothiazole ring, imidazole ring, pyrazole ring, furazane ring, triazole ring, pyran ring, pyridine ring , Pyridazine ring, pyrimidine ring, pyrazine ring and 1,3,5-triazine ring.
- aromatic ring a benzene ring, a condensed benzene ring and biphenyls are preferable.
- 1,3,5-triazine ring is preferably used.
- compounds disclosed in JP-A No. 2001-166144 are preferably used.
- the number of carbon atoms in the aromatic ring of the retardation developer is preferably 2 to 20, more preferably 2 to 12, still more preferably 2 to 8, and more preferably 2 to 6. Most preferred.
- the bonding relationship between two aromatic rings can be classified into (a) when forming a condensed ring, (b) when directly connecting with a single bond, and (c) when connecting via a linking group (for aromatic rings). , Spiro bonds cannot be formed).
- the bond relationship may be any of (a) to (c).
- condensed ring examples include an indene ring, a naphthalene ring, an azulene ring, a fluorene ring, a phenanthrene ring, an anthracene ring, an acenaphthylene ring, a biphenylene ring, a naphthacene ring, Pyrene ring, indole ring, isoindole ring, benzofuran ring, benzothiophene ring, indolizine ring, benzoxazole ring, benzothiazole ring, benzimidazole ring, benzotriazole ring, purine ring, indazole ring, chromene ring, quinoline ring, isoquinoline Ring, quinolidine ring, quinazoline ring, cinnoline ring, quinoxaline ring, phthalazine
- the single bond is preferably a bond between carbon atoms of two aromatic rings.
- Two aromatic rings may be bonded by two or more single bonds to form an aliphatic ring or a non-aromatic heterocyclic ring between the two aromatic rings.
- the linking group is also preferably bonded to carbon atoms of two aromatic rings.
- the linking group is preferably an alkylene group, an alkenylene group, an alkynylene group, —CO—, —O—, —NH—, —S—, or a combination thereof. Examples of linking groups composed of combinations are shown below. In addition, the relationship between the left and right in the following examples of the linking group may be reversed.
- substituents include halogen atoms (F, Cl, Br, I), hydroxyl groups, carboxyl groups, cyano groups, amino groups, nitro groups, sulfo groups, carbamoyl groups, sulfamoyl groups, ureido groups, alkyl groups, alkenyls.
- alkynyl group alkynyl group, aliphatic acyl group, aliphatic acyloxy group, alkoxy group, alkoxycarbonyl group, alkoxycarbonylamino group, alkylthio group, alkylsulfonyl group, aliphatic amide group, aliphatic sulfonamido group, aliphatic substituted amino group
- the number of carbon atoms in the alkyl group is preferably 1-8.
- a chain alkyl group is preferable to a cyclic alkyl group, and a linear alkyl group is particularly preferable.
- the alkyl group may further have a substituent (for example, a hydroxy group, a carboxy group, an alkoxy group, an alkyl-substituted amino group).
- Examples of alkyl groups (including substituted alkyl groups) include methyl, ethyl, n-butyl, n-hexyl, 2-hydroxyethyl, 4-carboxybutyl, 2-methoxyethyl and 2-methoxyethyl.
- Each group of a diethylaminoethyl group is included.
- the alkenyl group preferably has 2 to 8 carbon atoms.
- a chain alkenyl group is preferable to a cyclic alkenyl group, and a linear alkenyl group is particularly preferable.
- the alkenyl group may further have a substituent. Examples of the alkenyl group include a vinyl group, an allyl group, and a 1-hexenyl group.
- the number of carbon atoms of the alkynyl group is preferably 2-8.
- a chain alkynyl group is preferable to a cyclic alkynyl group, and a linear alkynyl group is particularly preferable.
- the alkynyl group may further have a substituent. Examples of the alkynyl group include ethynyl group, 1-butynyl group and 1-hexynyl group.
- the number of carbon atoms in the aliphatic acyl group is preferably 1-10.
- Examples of the aliphatic acyl group include an acetyl group, a propanoyl group, and a butanoyl group.
- the number of carbon atoms in the aliphatic acyloxy group is preferably 1-10.
- Examples of the aliphatic acyloxy group include an acetoxy group.
- the number of carbon atoms of the alkoxy group is preferably 1-8.
- the alkoxy group may further have a substituent (for example, an alkoxy group).
- a substituent for example, an alkoxy group.
- Examples of the alkoxy group (including a substituted alkoxy group) include a methoxy group, an ethoxy group, a butoxy group, and a methoxyethoxy group.
- the number of carbon atoms of the alkoxycarbonyl group is preferably 2 to 10.
- Examples of the alkoxycarbonyl group include a methoxycarbonyl group and an ethoxycarbonyl group.
- the number of carbon atoms of the alkoxycarbonylamino group is preferably 2 to 10.
- Examples of the alkoxycarbonylamino group include a methoxycarbonylamino group and an ethoxycarbonylamino group.
- the number of carbon atoms of the alkylthio group is preferably 1-12.
- Examples of the alkylthio group include a methylthio group, an ethylthio group, and an octylthio group.
- the number of carbon atoms of the alkylsulfonyl group is preferably 1-8.
- Examples of the alkylsulfonyl group include a methanesulfonyl group and an ethanesulfonyl group.
- the number of carbon atoms in the aliphatic amide group is preferably 1-10.
- Examples of the aliphatic amide group include acetamide.
- the number of carbon atoms in the aliphatic sulfonamide group is preferably 1-8.
- Examples of the aliphatic sulfonamido group include a methanesulfonamido group, a butanesulfonamido group, and an n-octanesulfonamido group.
- the number of carbon atoms of the aliphatic substituted amino group is preferably 1-10.
- Examples of the aliphatic substituted amino group include a dimethylamino group, a diethylamino group, and a 2-carboxyethylamino group.
- the number of carbon atoms in the aliphatic substituted carbamoyl group is preferably 2 to 10.
- Examples of the aliphatic substituted carbamoyl group include a methylcarbamoyl group and a diethylcarbamoyl group.
- the number of carbon atoms of the aliphatic substituted sulfamoyl group is preferably 1-8.
- Examples of the aliphatic substituted sulfamoyl group include a methylsulfamoyl group and a diethylsulfamoyl group.
- the number of carbon atoms of the aliphatic substituted ureido group is preferably 2 to 10.
- Examples of the aliphatic substituted ureido group include a methylureido group.
- non-aromatic heterocyclic groups examples include piperidino groups and morpholino groups.
- the molecular weight of the retardation developer is preferably 300 to 800.
- each R 1 independently represents an aromatic ring or a heterocyclic ring having a substituent in at least one of the ortho position, the meta position, and the para position.
- Each X independently represents a single bond or NR 2 —.
- each R 2 independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, an alkenyl group, an aryl group, or a heterocyclic group.
- the aromatic ring represented by R 1 is preferably phenyl or naphthyl, and particularly preferably phenyl.
- the aromatic ring represented by R 1 may have at least one substituent at any substitution position.
- substituents include halogen atom, hydroxyl group, cyano group, nitro group, carboxyl group, alkyl group, alkenyl group, aryl group, alkoxy group, alkenyloxy group, aryloxy group, acyloxy group, alkoxycarbonyl group, Alkenyloxycarbonyl group, aryloxycarbonyl group, sulfamoyl group, alkyl-substituted sulfamoyl group, alkenyl-substituted sulfamoyl group, aryl-substituted sulfamoyl group, sulfonamide group, carbamoyl, alkyl-substituted carbamoyl group, alkenyl-
- the heterocyclic group represented by R 1 preferably has aromaticity.
- the heterocycle having aromaticity is generally an unsaturated heterocycle, preferably a heterocycle having the largest number of double bonds.
- the heterocyclic ring is preferably a 5-membered ring, 6-membered ring or 7-membered ring, more preferably a 5-membered ring or 6-membered ring, and most preferably a 6-membered ring.
- the hetero atom of the heterocyclic ring is preferably a nitrogen atom, a sulfur atom or an oxygen atom, and particularly preferably a nitrogen atom.
- heterocyclic ring having aromaticity a pyridine ring (2-pyridyl or 4-pyridyl as the heterocyclic group) is particularly preferable.
- the heterocyclic group may have a substituent. Examples of the substituent of the heterocyclic group are the same as the examples of the substituent of the aryl moiety.
- the heterocyclic group is preferably a heterocyclic group having a free valence on the nitrogen atom.
- the heterocyclic group having a free valence on the nitrogen atom is preferably a 5-membered ring, 6-membered ring or 7-membered ring, more preferably a 5-membered ring or 6-membered ring, and a 5-membered ring. Is most preferred.
- the heterocyclic group may have a plurality of nitrogen atoms. Further, the heterocyclic group may have a hetero atom other than the nitrogen atom (for example, O, S). Examples of heterocyclic groups having free valences on nitrogen atoms are shown below. Here, —C 4 H 9 n represents nC 4 H 9 .
- the alkyl group represented by R 2 may be a cyclic alkyl group or a chain alkyl group, but a chain alkyl group is preferable, and a linear alkyl group is more preferable than a branched chain alkyl group. preferable.
- the alkyl group preferably has 1 to 30 carbon atoms, more preferably 1 to 20, more preferably 1 to 10, still more preferably 1 to 8, and further preferably 1 to 6. Most preferred.
- the alkyl group may have a substituent. Examples of the substituent include a halogen atom, an alkoxy group (for example, methoxy group, ethoxy group) and an acyloxy group (for example, acryloyloxy group, methacryloyloxy group).
- the alkenyl group represented by R 2 may be a cyclic alkenyl group or a chain alkenyl group, but is preferably a chain alkenyl group, and is more preferably a linear alkenyl group than a branched chain alkenyl group. More preferably it represents a group.
- the number of carbon atoms of the alkenyl group is preferably 2 to 30, more preferably 2 to 20, further preferably 2 to 10, still more preferably 2 to 8, and further preferably 2 to 6 is most preferred.
- the alkenyl group may have a substituent. Examples of the substituent are the same as those of the alkyl group described above.
- the aromatic ring group and heterocyclic group represented by R 2 are the same as the aromatic ring and heterocyclic ring represented by R 1 , and the preferred range is also the same.
- the aromatic ring group and the heterocyclic group may further have a substituent, and examples of the substituent are the same as those of the aromatic ring and heterocyclic ring of R 1 .
- the compound represented by the general formula (I) is, for example, a method described in JP-A No. 2003-344655, and the compound represented by the general formula (II) is, for example, a method described in JP-A-2005-134484. Can be synthesized by a known method.
- rod-like compounds having a linear molecular structure can be preferably used in addition to the above-mentioned discotic compounds.
- the linear molecular structure means that the molecular structure of the rod-like compound is linear in the most thermodynamically stable structure.
- the most thermodynamically stable structure can be obtained by crystal structure analysis or molecular orbital calculation.
- molecular orbital calculation is performed using molecular orbital calculation software (for example, WinMOPAC2000, manufactured by Fujitsu Limited), and a molecular structure that minimizes the heat of formation of a compound can be obtained.
- the molecular structure being linear means that in the thermodynamically most stable structure obtained by calculation as described above, the angle of the main chain constituting the molecular structure is 140 degrees or more.
- the rod-shaped compound having at least two aromatic rings is preferably a compound represented by the following general formula (11).
- Ar 1 -L 1 -Ar 2 In the general formula (11), Ar 1 and Ar 2 are each independently an aromatic group.
- the aromatic group includes an aryl group (aromatic hydrocarbon group), a substituted aryl group, an aromatic heterocyclic group, and a substituted aromatic heterocyclic group.
- An aryl group and a substituted aryl group are more preferable than an aromatic heterocyclic group and a substituted aromatic heterocyclic group.
- the heterocyclic ring of the aromatic heterocyclic group is generally unsaturated.
- the aromatic heterocycle is preferably a 5-membered ring, 6-membered ring or 7-membered ring, more preferably a 5-membered ring or 6-membered ring.
- Aromatic heterocycles generally have the most double bonds.
- a hetero atom a nitrogen atom, an oxygen atom or a sulfur atom is preferable, and a nitrogen atom or a sulfur atom is more preferable.
- a benzene ring As the aromatic ring of the aromatic group, a benzene ring, a furan ring, a thiophene ring, a pyrrole ring, an oxazole ring, a thiazole ring, an imidazole ring, a triazole ring, a pyridine ring, a pyrimidine ring and a pyrazine ring are preferable, and a benzene ring is particularly preferable. .
- Examples of the substituent of the substituted aryl group and the substituted aromatic heterocyclic group include a halogen atom (F, Cl, Br, I), a hydroxyl group, a carboxyl group, a cyano group, an amino group, an alkylamino group (for example, methyl Amino group, ethylamino group, butylamino group, dimethylamino group), nitro group, sulfo group, carbamoyl group, alkylcarbamoyl group (for example, N-methylcarbamoyl group, N-ethylcarbamoyl group, N, N-) Dimethylcarbamoyl group), sulfamoyl group, alkylsulfamoyl group (eg, N-methylsulfamoyl group, N-ethylsulfamoyl group, N, N-dimethylsulfamoyl group), ureido Group, alky
- preferable substituents include a halogen atom, a cyano group, a carboxyl group, a hydroxyl group, an amino group, an alkylamino group, an acyl group, an acyloxy group, an amide group, an alkoxycarbonyl group, an alkoxy group, an alkylthio group, and an alkyl group.
- a halogen atom a cyano group
- carboxyl group a hydroxyl group
- an amino group an alkylamino group
- an acyl group an acyloxy group
- an amide group an alkoxycarbonyl group
- an alkoxy group an alkylthio group
- the alkyl moiety of the alkylamino group, alkoxycarbonyl group, alkoxy group, and alkylthio group and the alkyl group may further have a substituent.
- substituents of the alkyl group include halogen atom, hydroxyl group, carboxyl group, cyano group, amino group, alkylamino group, nitro group, sulfo group, carbamoyl group, alkylcarbamoyl group, sulfamoyl group, alkylsulfur group.
- a halogen atom As the substituent for the alkyl moiety and the alkyl group, a halogen atom, a hydroxyl group, an amino group, an alkylamino group, an acyl group, an acyloxy group, an acylamino group, an alkoxycarbonyl group, and an alkoxy group are preferable.
- L1 is a divalent linking group selected from an alkylene group, an alkenylene group, an alkynylene group, —O—, —CO— and a combination thereof.
- the alkylene group may have a cyclic structure.
- cyclic alkylene group cyclohexylene is preferable, and 1,4-cyclohexylene is particularly preferable.
- chain alkylene group a linear alkylene group is more preferable than a branched alkylene group.
- the number of carbon atoms of the alkylene group is preferably 1-20, more preferably 1-15, still more preferably 1-10, still more preferably 1-8, and most preferably 1-6. It is.
- the alkenylene group and the alkynylene group preferably have a chain structure rather than a cyclic structure, and more preferably have a linear structure rather than a branched chain structure.
- the number of carbon atoms of the alkenylene group and the alkynylene group is preferably 2 to 10, more preferably 2 to 8, further preferably 2 to 6, further preferably 2 to 4, and most preferably 2. (Vinylene group or ethynylene group).
- the arylene group preferably has 6 to 20 carbon atoms, more preferably 6 to 16, and still more preferably 6 to 12.
- the angle formed by Ar 1 and Ar 2 across L 1 is preferably 140 degrees or more.
- a compound represented by the following formula (12) is more preferable.
- Ar 1 -L 2 -XL 3 -Ar 2 Ar 1 and Ar 2 are each independently an aromatic group.
- the definition and examples of the aromatic group are the same as those of Ar 1 and Ar 2 in the general formula (12).
- L 2 and L 3 are each independently a divalent linking group selected from an alkylene group, —O—, —CO—, and a group consisting of a combination thereof.
- the alkylene group preferably has a chain structure rather than a cyclic structure, and more preferably has a linear structure rather than a branched chain structure.
- the number of carbon atoms of the alkylene group is preferably 1 to 10, more preferably 1 to 8, still more preferably 1 to 6, further preferably 1 to 4, and 1 or 2 (methylene group). Or an ethylene group) is most preferable.
- L 2 and L 3 are particularly preferably —O—CO— or CO—O—.
- X represents a 1,4-cyclohexylene group, a vinylene group or an ethynylene group.
- Specific examples of the compound represented by the general formula (11) or (12) include compounds described in [Chemical Formula 1] to [Chemical Formula 11] of JP-A No. 2004-109657.
- Two or more rod-like compounds having a maximum absorption wavelength ( ⁇ max) longer than 250 nm in the ultraviolet absorption spectrum of the solution may be used in combination.
- the rod-like compound can be synthesized with reference to the methods described in the literature.
- rod-like aromatic compounds described on pages 11 to 14 of JP-A-2004-50516 may be used as the retardation developer.
- the retardation developer one kind of compound can be used alone, or two or more kinds of compounds can be mixed and used. It is preferable to use two or more different compounds as the retardation enhancer because the retardation adjustment range is widened and can be easily adjusted to a desired range.
- the amount of addition of the retardation developer is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass with respect to 100 parts by mass of cellulose acylate.
- the retardation developer may be added to the dope.
- the addition may be performed at any timing, for example, the retardation developer may be dissolved in an organic solvent such as alcohol, methylene chloride, dioxolane, and then added to the cellulose acylate solution (dope), or You may add directly in dope composition.
- the ratio of the discotic compound is preferably 0.1 to 20%, more preferably 0.5 to 15%, more preferably 1 to 10 based on the total mass of the discotic compound and the rod-shaped compound. % Is particularly preferred.
- a polymer additive can be used as in the case of the low molecular weight compound.
- the polymer additive is selected from polyester polymers, styrene polymers, acrylic polymers, and copolymers thereof, and aromatic polyesters are preferred.
- the aromatic polyester polymer can be obtained by copolymerizing a monomer having an aromatic ring with the polyester polymer.
- the monomer having an aromatic ring is at least one monomer selected from aromatic dicarboxylic acids having 8 to 20 carbon atoms and aromatic diols having 6 to 20 carbon atoms.
- aromatic dicarboxylic acid having 8 to 20 carbon atoms examples include phthalic acid, terephthalic acid, isophthalic acid, 1,5-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,8- There are naphthalenedicarboxylic acid and 2,6-naphthalenedicarboxylic acid.
- preferable aromatic dicarboxylic acids are phthalic acid, terephthalic acid, and isophthalic acid. These can be used individually or as a mixture of two or more.
- aromatic diol having 6 to 20 carbon atoms examples include, but are not limited to, bisphenol A, 1,2-hydroxybenzene, 1,3-hydroxybenzene, 1,4-hydroxybenzene, and 1,4-benzenedimethanol. Of these, bisphenol A, 1,4-hydroxybenzene, and 1,4-benzenedimethanol are preferred. These can be used individually or as a mixture of two or more.
- dicarboxylic acid other than the aromatic dicarboxylic acid that can constitute the aromatic polyester polymer examples include succinic acid, adipic acid, and the like, and these can be used singly or as a mixture of two or more.
- diols other than the above aromatic diol that can constitute the aromatic polyester polymer examples include alkylene glycols such as ethylene glycol, diethylene glycol, 1,2-propylene glycol, and 2-methyl 1,3-propanediol. Can be used as one kind or a mixture of two or more kinds.
- the end of the polyester may be sealed with an alkyl group or an aromatic group, or a hydroxyl group may remain.
- n the number of repetitions.
- Examples of the retardation developing agent according to the present invention include, for example, a discotic compound and a rod-like compound among the retardation developing agents, among which triazine compounds and rod-like compounds having a plurality of aromatic rings (1 ) To (7) are preferred.
- an ultraviolet absorber is preferably used for the cellulose ester solution from the viewpoint of preventing deterioration of a polarizing plate or liquid crystal.
- the ultraviolet absorber those excellent in the ability to absorb ultraviolet rays having a wavelength of 370 nm or less and having little absorption of visible light having a wavelength of 400 nm or more are preferably used from the viewpoint of good liquid crystal display properties.
- Specific examples of ultraviolet absorbers preferably used in the present invention include, for example, hindered phenol compounds, hydroxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex compounds Etc.
- hindered phenol compounds examples include 2,6-di-tert-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate].
- benzotriazole compounds include 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2,2-methylenebis (4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol), (2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-tert-butylanilino) -1,3,5- Triazine, triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], N, N′-hexamethylenebis (3,5-di-tert-butyl-4- Hydroxy-hydrocinnamide), 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benze 2- (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) -5-chlorobenzotri
- the amount of these ultraviolet light inhibitors added is preferably 1 ppm to 1.0%, more preferably 10 to 1000 ppm by mass in the whole cellulose ester film.
- the film of the present invention contains a release accelerator from the viewpoint of more releasability.
- the release accelerator can be included, for example, in a proportion of 0.001 to 1% by mass, and the addition of 0.5% by mass or less is preferable because separation of the release agent from the film hardly occurs. 005% by mass or more is preferable because a desired peeling reduction effect can be obtained. Therefore, it is preferably included at a rate of 0.005 to 0.5% by mass, and at a rate of 0.01 to 0.3% by mass. More preferably.
- the peeling accelerator known ones can be adopted, and organic and inorganic acidic compounds, surfactants, chelating agents and the like can be used. Among them, polyvalent carboxylic acids and esters thereof are effective, and in particular, ethyl esters of citric acid can be used effectively.
- the film of the present invention is generally added with fine particles in order to prevent the film from being scratched or deteriorated in transportability.
- They are called matting agents, anti-blocking agents or anti-scratching agents and have been used conventionally. They are not particularly limited as long as they have the above-described functions, and may be an inorganic compound matting agent or an organic compound matting agent.
- the inorganic compound matting agent include silicon-containing inorganic compounds (for example, silicon dioxide, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate, etc.), titanium oxide, and zinc oxide.
- silicon-containing inorganic compounds for example, silicon dioxide, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate, etc.
- titanium oxide titanium oxide
- zinc oxide Aluminum oxide, barium oxide, zirconium oxide, strongtium oxide, antimony oxide, tin oxide, tin oxide / antimony, calcium carbonate, talc, clay, calcined kaolin, calcium phosphate, etc., more preferably silicon-containing inorganic compounds and oxides
- silicon dioxide is particularly preferably used.
- silicon dioxide fine particles for example, commercially available products having trade names such as Aerosil R972, R974, R812, 200, 300, R202, OX50, TT600 (manufactured by Nippon Aerosil Co., Ltd.) can be used.
- zirconium oxide fine particles for example, those commercially available under trade names such as Aerosil R976 and R812 (manufactured by Nippon Aerosil Co., Ltd.) can be used.
- the organic compound matting agent include, for example, polymers such as silicone resin, fluorine resin, and acrylic resin, and among them, silicone resin is preferably used.
- silicone resins those having a three-dimensional network structure are particularly preferable.
- Tospearl 103, Tospearl 105, Tospearl 108, Tospearl 120, Tospearl 145, Tospearl 3120 and Tospearl 240 A commercial product having a trade name can be used.
- the method is not particularly limited, and there is no problem as long as a desired cellulose ester solution can be obtained by any method.
- an additive may be included at the stage of mixing the cellulose ester and the solvent, or the additive may be added after preparing a mixed solution with the cellulose ester and the solvent. Further, it may be added and mixed immediately before casting the dope, which is a so-called immediately preceding addition method, and the mixing is used by installing screw-type kneading online.
- a static mixer such as an inline mixer is preferable.
- the matting agent when the matting agent is not added in a large amount, the haze of the film does not increase, and when actually used in an LCD, inconveniences such as a decrease in contrast and generation of bright spots are unlikely to occur. If the amount is too small, the above-mentioned creaking and scratch resistance can be realized. From these viewpoints, it is preferably included in a proportion of 0.01 to 5.0% by mass, more preferably included in a proportion of 0.03 to 3.0% by mass, and a proportion of 0.05 to 1.0% by mass. It is particularly preferable to include
- the film of the present invention has an in-plane retardation value Ro (590) defined above in the range of 40 to 70 nm, and a retardation value Rt (590) in the thickness direction defined above of 100 to 200 nm. It is preferable to adjust so that it is in the range.
- Desired retardation can be adjusted by controlling the draw ratio at the time of film production, the amount of addition of the retardation adjusting agent in the film, and the like.
- a cellulose ester film that can be suitably used as a retardation film can be provided.
- the cellulose ester film of the present invention preferably has a haze of less than 0.5%, more preferably less than 0.3%. By setting the haze to less than 0.5%, there is an advantage that the transparency of the film becomes higher and it becomes easier to use as a cellulose ester film.
- the cellulose ester film of the present invention has an elastic modulus of preferably 3.5 or more, and more preferably 4.0 or more. By setting the elastic modulus to 4.0 or more, polarizing plate contraction during durability can be suppressed.
- the cellulose ester film is allowed to stand in a high-temperature and high-humidity atmosphere at 80 ° C. and 90% RH for 1000 hours, and then the presence or absence of bleeding out (crystal precipitation) on the surface of the cellulose ester film is confirmed by visual observation.
- Bleed out can be suppressed by adding a sugar ester compound having a structure similar to that of cellulose ester and a low degree of substitution.
- sucrose is particularly preferable from the viewpoints of compatibility and volatility.
- the film contrast value of the cellulose ester film of the present invention becomes higher as the orientation of the film becomes more uniform.
- the film contrast value is preferably 5000 or more, more preferably 7000 or more and 10,000 or less, and still more preferably 9000 or more and 10,000 or less.
- the polarizing plate of the present invention is treated at 60 ° C. and 90% RH for 250 hours, and then conditioned in a room at 23 ° C. and 55% RH for 24 hours to confirm the flatness of the polarizing plate.
- the cellulose ester with an ultra-low degree of substitution is susceptible to moisture, so the problem of shrinkage during durability is great, but the substitution degree of the sugar ester compound is reduced, leaving more hydroxyl groups, and the cellulose ester with a low degree of substitution By just softening the hydrogen bond with the sugar ester compound, the influence of shrinkage on the polarizing plate can be reduced.
- the polarizing plate of the present invention is cut into a square having a size of 20 cm ⁇ 20 cm and bonded to a glass substrate using an acrylic adhesive. Next, the bonded polarizing plate was peeled off from the glass with a strength of 5N from the corner portion, and the number of polarizing plates that were not completely peeled was counted to evaluate the reworkability.
- (Front contrast) Measurement was performed after the backlight of the liquid crystal display device of the present invention was continuously turned on for 1 hour.
- EZ-Contrast 160D manufactured by ELDIM was used, and the luminance from the normal direction of the display screen of white display and black display was measured with a liquid crystal display device, and the ratio was defined as the front contrast.
- Front contrast (brightness of white display measured from normal direction of display device) / (brightness of black display measured from normal direction of display device) If the value of the front contrast is 1000 or more, there is no practical problem and it is more preferably 1100 or more.
- the film thickness of the film of the present invention is 10 to 35 ⁇ m. Further, it is more preferably 20 to 35 ⁇ m. By setting it to 10 ⁇ m or more, the waist of the film is maintained, which is preferable. When the thickness is 20 ⁇ m or more, the flatness of the film is easily maintained, and when the thickness is 35 ⁇ m or less, the transparency of the film is advantageous.
- the length of the film is preferably in the range of 5000 to 10,000 m, and the width of the film is preferably in the range of 1.9 to 2.5 m.
- the film production method of the present invention comprises a step of dissolving a polymer in an organic solvent to prepare a dope (dope preparation step), a step of filtering the dope (filtration step), and casting the dope on a support.
- a process (casting process), a process of drying the obtained film (drying process), a process of stretching the obtained film (stretching process), and other processes as necessary.
- the film of the present invention is produced using a solution (dope) obtained by dissolving a cellulose ester in an organic solvent by a solvent cast method.
- the organic solvents may be used alone or in combination of two or more. From the viewpoint of production efficiency, it is preferable to use a solvent (good solvent) that dissolves cellulose ester alone and a solvent (poor solvent) that does not swell or dissolve cellulose ester alone.
- a preferable range of the mixing ratio of the good solvent and the poor solvent (good solvent: poor solvent) (mass ratio) is 70:30 to 98: 2.
- the good solvent is selected from ethers having 3 to 12 carbon atoms, ketones having 3 to 12 carbon atoms, esters having 3 to 12 carbon atoms, and halogenated hydrocarbons having 1 to 6 carbon atoms. It is preferable to include a solvent.
- the ether, ketone and ester may have a cyclic structure.
- a compound having two or more functional groups of ether, ketone and ester (that is, —O—, —CO— and COO—) can also be used as the organic solvent.
- the organic solvent may have another functional group such as an alcoholic hydroxyl group (hydroxyl group). In the case of an organic solvent having two or more types of functional groups, the number of carbon atoms may be within the specified range of the compound having any functional group.
- ethers having 3 to 12 carbon atoms include diisopropyl ether, dimethoxymethane, dimethoxyethane, 1,4-dioxane, 1,3-dioxolane, tetrahydrofuran, anisole and phenetole.
- ketones having 3 to 12 carbon atoms include acetone, methyl ethyl ketone, diethyl ketone, diisobutyl ketone, cyclohexanone and methylcyclohexanone.
- esters having 3 to 12 carbon atoms include ethyl formate, propyl formate, pentyl formate, methyl acetate, ethyl acetate and pentyl acetate.
- organic solvent having two or more kinds of functional groups examples include 2-ethoxyethyl acetate, 2-methoxyethanol and 2-butoxyethanol.
- the number of carbon atoms of the halogenated hydrocarbon is preferably 1 or 2, and most preferably 1.
- the halogen of the halogenated hydrocarbon is preferably chlorine.
- the proportion of halogen atoms in the halogenated hydrocarbon substituted with halogen is preferably 25 to 75 mol%, more preferably 30 to 70 mol%, and more preferably 35 to 65 mol%. More preferably, it is most preferably 40 to 60 mol%.
- Methylene chloride is a typical halogenated hydrocarbon.
- the poor solvent for example, methanol, ethanol, n-butanol, cyclohexane, cyclohexanone and the like are preferably used.
- a cellulose ester solution can be prepared by a general method.
- a general method means processing at a temperature of 0 ° C. or higher (ordinary temperature or high temperature).
- the solution can be prepared by using a dope preparation method and apparatus in a normal solvent cast method.
- the amount of cellulose ester is adjusted so that it is contained in an amount of 10 to 40% by mass in the obtained solution (dope solution).
- the amount of cellulose ester is more preferably 10 to 30% by mass.
- Arbitrary additives may be added to the organic solvent (main solvent).
- the solution can be prepared by stirring the cellulose ester and the organic solvent at room temperature (0 to 40 ° C.).
- the high concentration solution may be stirred under pressure and heating conditions. Specifically, the cellulose ester and the organic solvent are placed in a pressure vessel and sealed, and stirred while heating to a temperature not lower than the boiling point of the solvent at normal temperature and in a range where the solvent does not boil.
- the heating temperature is usually 40 ° C. or higher, preferably 60 to 200 ° C., more preferably 80 to 110 ° C.
- Each component may be coarsely mixed in advance and then placed in a container. Moreover, you may put into a container sequentially.
- the container needs to be configured so that it can be stirred.
- the container can be pressurized by injecting an inert gas such as nitrogen gas. Moreover, you may utilize the raise of the vapor pressure of the solvent by heating. Or after sealing a container, you may add each component under pressure.
- a jacket type heating device can be used.
- the entire container can also be heated by providing a plate heater outside the container and piping to circulate the liquid.
- the stirring blade preferably has a length that reaches the vicinity of the wall of the container.
- a scraping blade is preferably provided at the end of the stirring blade in order to renew the liquid film on the vessel wall.
- instruments such as a pressure gauge and a thermometer may be installed. Each component is dissolved in a solvent in a container.
- the prepared dope is taken out of the container after cooling, or taken out and then cooled using a heat exchanger or the like.
- the solution can also be prepared by a cooling dissolution method.
- the cellulose ester can be dissolved in an organic solvent that is difficult to dissolve by a normal dissolution method.
- dissolution method there exists an effect that a uniform solution can be obtained rapidly according to a cooling melt
- filtration process Various known filtration devices can be used for filtering the cellulose ester solution. That is, when roughly classified as a filter, it can be divided into a continuous filter and a batch pressure filter, and as a continuous filter, it can be divided into a belt type, a multiple disk type, a screw press type, a filter press type, etc. Examples of the batch pressure filter include a leaf type and a candle type.
- a filter press device a paper filter device, a leaf filter device, a drum filter device, a precoat filter device, or the like can be used.
- the industrially most advantageous product is a filter press apparatus, and the filter press apparatus may be pre-coated and used.
- the filter press apparatus 40 to 50 plates of about 60 cm square are used, and a net is attached to each plate, and a filter paper or cotton cloth is installed between the nets.
- a plurality of these filter press apparatuses may be used for filtration in multiple stages.
- the leaf filter device can be suitably used.
- a sintered metal filter As the filter material, a sintered metal filter, a non-woven metal filter, a cotton cloth filter, a paper filter, or the like may be used.
- the solution casting method used in the method for producing a film of the present invention is a glass plate or metal plate having a high smoothness after the dope is prepared in a glass or metal container and filtered after being carried out in a small amount.
- the film is cast to a desired film thickness on a support such as a small die or a doctor blade. After casting, primary drying is performed, and the film is peeled off from the support, framed as necessary, and post-dried.
- a solution casting film forming method and a solution casting film forming apparatus conventionally used for producing a cellulose triacetate film can be used.
- the dope prepared in the dissolving machine (kettle) is filtered, and the dope is finally prepared. After that, the dope is sent from the dope discharge port to the pressure die through a pressure metering gear pump capable of delivering a constant amount of liquid with high accuracy, for example, by the rotational speed, and the dope is run endlessly from the die (slit) of the pressure die.
- the dope film (also referred to as a web) is peeled off from the support at a peeling point that is uniformly cast on the support (drum or band) and the support has almost gone around. Both ends of the obtained web are sandwiched between clips, transported by a tenter while keeping the width, dried, then transported by a roll group of a drying device, dried, and wound up to a predetermined length by a winder.
- the combination of the tenter and the roll group dryer varies depending on the purpose.
- the surface of the drum or band is preferably finished in a mirror state.
- the casting and drying methods in the solvent casting method are described in U.S. Pat. Nos. 2,336,310, 2,367,603, 2,492,078, 2,492,977. No.
- the dope is preferably cast on a drum or band adjusted to an arbitrary surface temperature.
- a cellulose acylate film in the case of a laminated film, can be produced from two or more kinds of prepared cellulose ester solutions (dope) by a solvent cast method.
- the dope is cast on a drum or band, and the solvent is evaporated to form a film.
- the dope before casting is preferably adjusted in concentration so that the solid content is 18 to 35% by mass.
- the surface of the drum or band is preferably finished in a mirror state.
- the dope is preferably cast on a drum or a band. After casting, it is preferable to dry it by applying air for 2 seconds or more. The obtained film can be peeled off from the drum or band and further dried with high-temperature air whose temperature is successively changed from 100 ° C. to 160 ° C. to evaporate the residual solvent.
- the above method is described in Japanese Patent Publication No. 5-17844. According to this method, it is possible to shorten the time from casting to stripping. In order to carry out this method, it is necessary for the dope to gel at the surface temperature of the drum or band during casting.
- the cellulose ester solution (dope) obtained can be formed by casting the two or more cellulose ester solutions on a smooth band or drum as a support.
- the method for producing the film of the present invention is not particularly limited except the above, and a known co-casting method can be used.
- a film may be produced by laminating and laminating a solution containing a cellulose ester from a plurality of casting openings provided at intervals in the traveling direction of the metal support. The methods described in JP-A Nos. 158414, 1-122419, and 11-198285 can be applied.
- a film may be formed by casting a cellulose ester solution from two casting ports.
- JP-B-60-27562, JP-A-61-94724, JP-A-61-947245 It can be carried out by the methods described in JP-A Nos.
- the cellulose ester film casting method described in JP-A-56-162617 is a method of wrapping a flow of a high-viscosity cellulose ester solution with a low-viscosity cellulose ester solution and simultaneously extruding the high- and low-viscosity cellulose ester solution. Good.
- the outer solution described in JP-A-61-94724 and JP-A-61-94725 contains a larger amount of an alcohol component which is a poor solvent than the inner solution.
- the film cast on the metal support is peeled off by the first casting port, and the second casting is performed on the side that is in contact with the metal support surface.
- a film may be produced, for example, a method described in Japanese Patent Publication No. 44-20235.
- the cellulose ester solution to be cast may be the same solution or different cellulose ester solutions and is not particularly limited. In order to give a function to a plurality of cellulose ester layers, a cellulose ester solution corresponding to the function may be extruded from each casting port.
- the cellulose ester solution according to the present invention can be cast simultaneously with other functional layers (for example, an adhesive layer, a dye layer, an antistatic layer, an antihalation layer, a UV absorbing layer, a polarizing layer).
- other functional layers for example, an adhesive layer, a dye layer, an antistatic layer, an antihalation layer, a UV absorbing layer, a polarizing layer.
- the film formation is simultaneous or sequential multilayer casting film formation.
- the inner and outer thicknesses are not particularly limited, but preferably the outer side is preferably 0.2 to 50% of the total film thickness, more preferably 2 to 30%. .
- the total thickness of the layer in contact with the metal support and the layer in contact with the air side is defined as the outer thickness.
- a cellulose ester film having a laminated structure can be produced by co-casting cellulose ester solutions having different additive concentrations such as the above-mentioned plasticizer, ultraviolet absorber and matting agent.
- a cellulose ester film having a structure of skin layer / core layer / skin layer can be produced.
- the matting agent can be contained in the skin layer in a large amount or only in the skin layer.
- the plasticizer and the ultraviolet absorber can be contained in the core layer more than the skin layer, and may be contained only in the core layer.
- the type of plasticizer and ultraviolet absorber can be changed between the core layer and the skin layer.
- the skin layer contains a low-volatile plasticizer and / or an ultraviolet absorber, and the core layer has excellent plasticity. It is also possible to add a plasticizer or an ultraviolet absorber excellent in ultraviolet absorption. Moreover, it is also a preferable aspect that a release agent is contained only in the skin layer on the metal support side. It is also preferable to add more alcohol, which is a poor solvent, to the skin layer than the core layer in order to cool the metal support by the cooling drum method to gel the solution.
- the Tg of the skin layer and the core layer may be different, and the Tg of the core layer is preferably lower than the Tg of the skin layer.
- the viscosity of the solution containing the cellulose ester during casting may be different between the skin layer and the core layer, and the viscosity of the skin layer is preferably smaller than the viscosity of the core layer. It may be smaller than the viscosity.
- Drying is performed by a method of applying wind at a predetermined temperature to both sides of the web (film) being conveyed or a method using a heating means such as a microwave. Since rapid drying may impair the flatness of the film to be formed, it is preferable to dry at a temperature at which the solvent does not foam in the initial stage of drying, and to dry at a high temperature after the drying proceeds.
- the amount of residual solvent when peeling the web from the support is preferably 10 to 150% by mass, more preferably 20 to 40% by mass or 60 to 130% by mass. %, Particularly preferably 20 to 30% by mass or 70 to 120% by mass.
- the residual solvent amount can be expressed by the following formula.
- Residual solvent amount (% by mass) ⁇ (MN) / N ⁇ ⁇ 100
- M is the mass of the web at an arbitrary point in time
- N is the mass when the web of which M is measured is dried at 110 ° C. for 3 hours.
- the film tends to shrink in the longitudinal direction or the width direction by evaporation of the solvent. Shrinkage increases with drying at higher temperatures. Drying while suppressing this shrinkage as much as possible is preferable for improving the flatness of the finished film. From this point, for example, as shown in Japanese Patent Application Laid-Open No. 62-46625, a method in which all or part of the drying process is performed while holding the width at both ends of the web with clips or pins in the width direction. (Tenter method) is preferable.
- the drying temperature in the drying step is preferably 100 to 145 ° C.
- the drying temperature, the amount of drying air, and the drying time vary depending on the solvent used, but may be appropriately selected according to the type and combination of the solvents used.
- the residual solvent amount of the film after drying is preferably 1% by mass or less, more preferably 0 to 0.1% by mass.
- the web (film) peeled from the support is preferably stretched when the amount of residual solvent in the web is less than 120% by mass.
- the present invention in order to improve the film performance, it may be positively stretched in the width direction.
- the film is stretched at a temperature 10 to 20 ° C. higher than Tg (glass transition temperature).
- Tg glass transition temperature
- the film of the present invention has a high glass transition temperature and is heated to a temperature higher than the glass transition temperature. Decomposition may begin. In such a case, in the present invention, it is particularly effective to stretch the film of the present invention by treatment during drying.
- stretching can be performed at a temperature at which the polymer does not decompose.
- the stretching method for example, in the case of stripping, the film is stretched by adjusting the speed of the film transport roller so that the film winding speed is higher than the film stripping speed.
- the film is stretched by increasing the transport speed of the transport roller at the transport destination relative to the transport speed of the transport roller on the near side in the transport direction. Further, the film can be stretched in the width direction by conveying the film while holding the film with a tenter and gradually increasing the width of the tenter.
- the stretching direction may be the casting direction, may be stretched in a direction perpendicular to the casting direction, or may be stretched in both directions depending on circumstances. At this time, stretching may be performed simultaneously, or stretching in one direction and then stretching in another direction.
- the stretching ratio in the width direction (TD direction) of the film (the ratio of the length after stretching relative to the original length) is preferably 1.03 to 3, more preferably 1.05 to 2. 5 times, more preferably 1.05 to 1.8 times. Further, the stretching ratio in the longitudinal direction (MD direction) of the film is preferably 1.01 to 1.2 times, more preferably 1.01 to 1.1 times.
- the winding machine relating to the production of the cellulose ester film in the present invention may be generally used, such as a constant tension method, a constant torque method, a taper tension method, a program tension control method with a constant internal stress, and the like. Can be rolled up.
- the thickness of the polymer film in the present invention (after drying) varies depending on the purpose of use, but is usually preferably in the range of 20 to 200 ⁇ m, more preferably in the range of 30 to 150 ⁇ m, and particularly preferably in the range of 30 to 80 ⁇ m. Most preferred.
- the film thickness may be adjusted by adjusting the solid content concentration contained in the dope, the slit gap of the die base, the extrusion pressure from the die, the support speed, and the like so as to obtain a desired thickness.
- the stretching speed is preferably 5% / min to 1000% / min, more preferably 10% / min to 500% / min.
- the stretching is preferably performed by a heat roll or / and a radiant heat source (such as an IR heater) or warm air. Moreover, you may provide a thermostat in order to improve the uniformity of temperature.
- L / W which is a ratio of the distance between rolls (L) and the film width (W)
- the width of the dryer should be set so that the hot air and heat source of the dryer do not hit the edges of the web in the dryer. However, it is also preferable that the length is shorter than the width of the web.
- the stretch ratio for the stretched film should be a predetermined thickness. Further, by stretching, it may be preferable that an improvement in planarity such as flatness can be achieved. Furthermore, in order to reduce the unevenness in thickness, by providing a gradient in the width direction of the stretching temperature, it may be possible to achieve more uniform stretching than stretching at a constant temperature.
- the cellulose ester film of the present invention Since the cellulose ester film of the present invention has high optical expression, it is preferably used as a retardation film as a protective film for a polarizing plate.
- the polarizing plate is formed by laminating and laminating a protective film on at least one surface of the polarizer.
- a conventionally known polarizer can be used.
- a hydrophilic polymer film such as a polyvinyl alcohol film is treated with a dichroic dye such as iodine and stretched.
- the bonding of the cellulose ester film and the polarizer is not particularly limited, but can be performed with an adhesive made of an aqueous solution of a water-soluble polymer.
- the water-soluble polymer adhesive is preferably a completely saponified polyvinyl alcohol aqueous solution.
- the film of the present invention is a protective film for polarizing plate / polarizer / protective film for polarizing plate / liquid crystal cell / film of the present invention / polarizer / protective film for polarizing plate, or protective film for polarizing plate / polarizer / It can use preferably by the structure of the film / liquid crystal cell of this invention / film of this invention / polarizer / protective film for polarizing plates.
- a liquid crystal cell such as a TN type, a VA type, or an OCB type
- a polarizing plate using the protective film for a polarizing plate according to the present invention has little deterioration under high temperature and high humidity conditions, and can maintain stable performance for a long time.
- the cellulose ester film of the present invention and the polarizing plate using the film can be used for liquid crystal cells and liquid crystal display devices in various display modes.
- TN Transmission Nematic
- IPS In-Plane Switching
- FLC Fluoroelectric Liquid Crystal
- AFLC Anti-Frequential Liquid Nyst
- HAN Hybrid Aligned Nematic
- the OCB mode liquid crystal cell is a liquid crystal display device using a bend alignment mode liquid crystal cell in which rod-like liquid crystalline molecules are aligned in a substantially opposite direction (symmetrically) between the upper part and the lower part of the liquid crystal cell.
- OCB mode liquid crystal cells are disclosed in US Pat. Nos. 4,583,825 and 5,410,422. Since the rod-like liquid crystal molecules are aligned symmetrically between the upper part and the lower part of the liquid crystal cell, the bend alignment mode liquid crystal cell has a self-optical compensation function.
- the bend alignment mode liquid crystal display device has an advantage of high response speed.
- rod-like liquid crystal molecules are aligned substantially vertically when no voltage is applied.
- the VA mode liquid crystal cell includes: (1) a narrowly defined VA mode liquid crystal cell in which rod-like liquid crystalline molecules are aligned substantially vertically when no voltage is applied, and substantially horizontally when a voltage is applied (Japanese Patent Laid-Open No. Hei 2-). (2) described in (2) liquid crystal cell (SID97, Digest of tech. Papers 28 (1997) 845 with VA mode multi-domain (MVA mode) for viewing angle expansion. ), (3) a liquid crystal cell (n-ASM mode) in which rod-like liquid crystalline molecules are substantially vertically aligned when no voltage is applied and twisted multi-domain alignment is applied when a voltage is applied (Sharp Technical Report No. 80, page 11); (4) A SURVAVAL mode liquid crystal cell (Monthly Display May 14th page (1999)) is included.
- the VA mode liquid crystal display device comprises a liquid crystal cell and two polarizing plates disposed on both sides thereof.
- the liquid crystal cell carries a liquid crystal between two electrode substrates.
- the film of the present invention is disposed between the liquid crystal cell and one polarizing plate, or between the liquid crystal cell and both polarizing plates. Arrange two.
- an optical compensation sheet made of the film of the present invention is used as a transparent protective film for a polarizing plate disposed between a liquid crystal cell and a polarizer.
- the above optical compensation sheet may be used only for the protective film (between the liquid crystal cell and the polarizer) of one polarizing plate, or two (between the liquid crystal cell and the polarizer) of both polarizing plates. You may use said optical compensation sheet for a sheet of protective film.
- the optical compensation sheet is used for only one polarizing plate, it is particularly preferable to use it as a protective film for the liquid crystal cell side of the backlight side polarizing plate of the liquid crystal cell.
- the film of the present invention is preferably on the VA cell side.
- the protective film may be a normal cellulose ester film.
- 40 to 80 ⁇ m is preferable, and examples thereof include, but are not limited to, commercially available KC4UY (40 ⁇ m manufactured by Konica Minolta Opto), KC5UX (60 ⁇ m manufactured by Konica Minolta Opto), TD80 (80 ⁇ m manufactured by Fujifilm), and the like.
- Parts described below represents “parts by mass”, and “%” represents “% by mass”.
- cellulose ester films 1 to 18 were produced according to the following procedure.
- cellulose ester film 1 (Dope solution) Cellulose ester (cellulose acetate propionate acetyl group substitution degree 0.1, propionyl group 1.5): 90 parts by mass Sugar ester compound 5: 10 parts by mass Methylene chloride: 300 parts by mass Ethanol: 40 parts by mass
- the components of the dope solution are put into the main dope charging kettle 1, heated and stirred, and completely dissolved, using the main filter 4 (Azumi Filter Paper Co., Ltd .: Azumi Filter Paper No. 24). Filtration was performed to prepare a dope. Subsequently, the dope was filtered with a dope filter 5 (manufactured by Nippon Seisen Co., Ltd .: Finemet NF).
- the belt was cast evenly on the stainless steel band support 101 at a temperature of 22 ° C. and a width of 2 m using a belt casting apparatus.
- the solvent was evaporated on the stainless steel band support 101 until the residual solvent amount reached 100%, and the stainless steel band support 101 was peeled off from the stainless steel band support 101 with a peeling tension of 162 N / m.
- the peeled cellulose ester web was evaporated at 35 ° C., slit to 1.6 m width, and then dried at a drying temperature of 135 ° C. while being stretched 1.3 times in the width direction by the tenter 105. . At this time, the residual solvent amount when starting stretching with the tenter 105 was 10%.
- drying is completed while the drying zone 106 at 120 ° C. and 130 ° C. is conveyed by a number of rolls, slit to 1.5 m width, A knurling process with a height of 10 mm and a thickness of 5 ⁇ m was performed, and the cellulose ester film 1 was obtained by winding it around a 6-inch inner diameter core with an initial tension of 220 N / m and a final tension of 110 N / m.
- the draw ratio in the MD direction calculated from the rotational speed of the stainless steel band support and the operating speed of the tenter was 1.01.
- cellulose ester films 2 to 18 were produced in the same manner as the cellulose ester film 1 except that the types of resins, types and amounts of additives, and film thicknesses were changed as shown in Tables 4 to 6.
- sugar esters 1 to 10 are sugar ester compounds represented by the above general formula (1), wherein R 1 to R 8 are substituted with the acyl groups shown in Table 5, and the degree of substitution is shown in Table 5. A compound with a degree of substitution. The amount of residual solvent in each of the obtained cellulose ester films 1 to 18 was 0.1%.
- a film 20 was produced in the same manner as the film 19 except that the resin was changed to a cyclic olefin resin (COP) (ARTON, manufactured by JSR Corporation).
- COP cyclic olefin resin
- the above three kinds of dopes were cast together from the co-casting die 10 on the traveling casting band.
- the core layer is made thickest by adjusting the casting amount of each dope, and as a result, simultaneous multilayer casting is performed so that the film thickness after stretching becomes the value of Table 7 below. Formed.
- the cast film was peeled off from the cast band, widened to a stretch rate of 30% using a tenter, and then relaxed at 135 ° C. for 60 seconds. Thereafter, the film was sent to a drying chamber and sufficiently dried while being conveyed while being wound around a roller.
- Cellulose ester films 22 to 27 As described in Table 7 below, cellulose ester films of each Example were obtained in the same manner as the cellulose ester film 21 except that the resin, additives, and film thickness were changed.
- In-plane retardation Ro (nx ⁇ ny) ⁇ d
- Thickness direction retardation Rt ((nx + ny) / 2 ⁇ nz) ⁇ d (Haze) Using a turbidimeter (NDH2000, Nippon Denshoku Industries Co., Ltd.), haze (surface quality haze%) of the film was measured in the same environment for 23 hours at 23 ° C. and 55% RH. It was.
- the elastic modulus was adjusted to a temperature of 23 ° C. and 55% RH for 24 hours, and according to the method described in JIS K7127, Tensilon RTA- manufactured by Orientec Co., Ltd. 100 was used, the shape of the test piece was a No. 1 type test piece, and the elastic modulus in the TD direction was measured at a test speed of 10 mm / min. ⁇ : 4.0 or more ⁇ : 3.5 or more and less than 4.0 ⁇ : 3.0 or more and less than 3.5 ⁇ : less than 3.0
- the elastic modulus is preferably ⁇ level or more, and ⁇ level Particularly preferred.
- bleed-out crystal precipitation
- a direct type fluorescent tube backlight light source an upper polarizing plate, a sample, and a lower polarizing plate are installed in order from the bottom so that each surface is horizontal.
- the sample and the upper polarizing plate are rotatable.
- Luminance was measured using BM-5A (manufactured by TOPCON) from the vertical direction of light emitted from the light source and sequentially transmitted through the upper polarizing plate, the sample, and the lower polarizing plate.
- the upper polarizing plate is rotated in a state where there is no sample, and is adjusted to a position where the luminance is the darkest (cross Nicol state). Insert the sample and rotate the sample under crossed Nicols to measure the minimum brightness.
- two polarizing plates, an upper polarizing plate and a lower polarizing plate are arranged in parallel Nicols, and the sample is rotated to measure the maximum luminance.
- the film contrast is (maximum luminance of the optical compensation sheet disposed between two polarizing plates in a parallel Nicol state) / (minimum luminance of the optical compensation sheet disposed between two polarizing plates in a crossed Nicol state). Asked. A: 9000 or more and less than 10,000 B: 7000 or more and less than 9000 B: 5000 or more and less than 7000 x: less than 5000
- the film contrast is preferably at least B level, and particularly preferably at the A level.
- Example 2 Preparation of polarizing plate> Using the obtained cellulose ester films 1 to 18 and 21 to 27, polarizing plates were produced by the following method.
- a 120 ⁇ m thick polyvinyl alcohol film was uniaxially stretched (temperature: 110 ° C., stretch ratio: 5 times). This was immersed in an aqueous solution composed of 0.075 g of iodine, 5 g of potassium iodide and 100 g of water for 60 seconds, and then immersed in an aqueous solution of 68 ° C. composed of 6 g of potassium iodide, 7.5 g of boric acid and 100 g of water. This was washed with water and dried to obtain a polarizer.
- a polarizer the cellulose ester films 1 to 18, 21 to 27, and a commercially available cellulose ester film (KC4UY, manufactured by Konica Minolta Opto Co., Ltd.) are used as a polarizing plate protective film on the back side.
- the polarizing plate was produced by bonding.
- Step 1 Films Cellulose ester films 1-18 and 21-27 were immersed in a 2 mol / l potassium hydroxide solution at 50 ° C. for 30 seconds, then washed with water and dried to obtain films whose surfaces were saponified.
- 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 lightly wiped off, and this was placed on the cellulose ester film treated in Step 1, and further placed on the back side cellulose ester film.
- Step 4 The cellulose ester films 1 to 18, 21 to 27 laminated in Step 3 were bonded to the polarizer and the back side cellulose ester film 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 prepared in Step 4 with the cellulose ester films 1 to 18, 21 to 27 and the back side cellulose ester film in a drier at 80 ° C. is dried for 2 minutes, and the corresponding polarized light Plates 1 to 18 and 21 to 27 were produced.
- the films 19 and 20 were coated with an ultraviolet curable adhesive (KRX492-25 manufactured by ADEKA) using an application device instead of an adhesive made of an aqueous solution of a polyvinyl alcohol resin, and then 300 mJ / cm using an ultraviolet irradiation device.
- Each of the corresponding polarizing plates is the same except that ultraviolet rays (irradiation ultraviolet wavelength: 365 nm, adhesive film thickness: 3 ⁇ m) are irradiated for 5 seconds with an integrated light quantity of 2 to cure and paste the ultraviolet curable adhesive. 19 and 20 were produced.
- the polarizing plate of the present invention was treated at 60 ° C. and 90% RH for 250 hours, and then conditioned in a room at 23 ° C. and 55% RH for 24 hours to confirm the flatness of the polarizing plate.
- ⁇ No swell or wrinkle
- ⁇ Little swell or wrinkle
- ⁇ Slight swell or wrinkle is seen
- ⁇ Swell or wrinkle is seen It is preferable that it is ⁇ level.
- Reworkability In an atmosphere of 23 ° C. and 55% RH, the produced polarizing plate is cut into a square with a size of 20 cm ⁇ 20 cm and bonded to a glass substrate using an acrylic adhesive. Next, the bonded polarizing plate is peeled off from the glass with a strength of 5 N from the corner. This operation was performed with 100 polarizing plates for one type of sample, and the number of polarizing plates that were not peeled completely due to tears in the polarizing plate was counted. Reworkability was ranked according to the following criteria. ⁇ : 0 to 5 sheets ⁇ : 6 to 10 sheets ⁇ : 11 to 15 sheets ⁇ : 16 sheets or more Reworkability is practically acceptable if it is ⁇ level or more, but is preferably ⁇ level or more. It is particularly preferred.
- Example 3 Provide of liquid crystal display device> A liquid crystal panel for measuring the viewing angle using the polarizing plate obtained in Example 2 was prepared as follows, and the characteristics as a liquid crystal display device were evaluated.
- liquid crystal display devices 1 to 27 corresponding to the polarizing plates 1 to 27 were respectively prepared by performing the absorption axis in the same direction as the polarizing plate bonded in advance.
- Front contrast (brightness of white display measured from normal direction of display device) / (brightness of black display measured from normal direction of display device)
- the evaluation rank of contrast was determined as follows. A: 1100 to 1200 or more ⁇ : 1000 to less than 1100 ⁇ : less than 1000 ⁇ If it is greater than or equal to ⁇ , there is no practical problem.
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Abstract
Description
アセチル基由来の炭素数:2×0.1=0.2
プロピオニル基由来の炭素数:3×1.5=4.5なので、総炭素数は4.7となる。
本発明のセルロースエステルフィルムは、従来のセルロースエステルフィルムに比べ、薄膜でかつ位相差と透過率を両立し、高い機械強度を持ったフィルムである。これを用いることで、収縮を抑制し、リワーク性を改善した偏光板と、コントラストの高い、液晶表示装置を提供することができた。
本発明のセルロースエステルフィルムは、炭素数が3~4のアシル基、又は、炭素数が2のアシル基および炭素数3~4のアシル基で置換され、かつアシル基置換度(総置換度)が1.0以上2.0未満であり、重量平均分子量(Mw)が150,000以下であるセルロースエステルを含有することを要する。位相差発現性の点から、該セルロースエステルは、炭素数3以上のアシル基の置換度が0.9以上2.0未満であることが好ましい。また、耐水性の点から、該セルロースエステルは、前記アシル基の総炭素数が4.4を超えた範囲内であるセルロースエステルを含有することが好ましい。炭素数が2~4の範囲内であるアシル基としては、アセチル基、プロピオニル基、及びブタノイル基を挙げることができる。
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。
本発明において「ピラノース構造またはフラノース構造の少なくとも1種の糖単位構造を1個以上12個以下有し、その糖単位構造の水酸基の一部または全部がエステル化された糖エステル化合物」を以下、単に「糖エステル化合物」とよぶ。
1)LC部
装置:日本分光(株)製カラムオーブン(JASCO CO-965)、ディテクター(JASCO UV-970-240nm)、ポンプ(JASCO PU-980)、デガッサ-(JASCO DG-980-50)
カラム:Inertsil ODS-3 粒子径5μm 4.6×250mm(ジーエルサイエンス(株)製)
カラム温度:40℃
流速:1ml/min
移動相:THF(1%酢酸):H2O(50:50)
注入量:3μl
2)MS部
装置:LCQ DECA(Thermo Quest(株)製)
イオン化法:エレクトロスプレーイオン化(ESI)法
Spray Voltage:5kV
Capillary温度:180℃
Vaporizer温度:450℃
<添加剤>
本発明では、糖エステル化合物以外に、可塑剤、リターデーション調整剤(リターデーション発現剤及びリターデーション低減剤)、紫外線吸収剤、酸化防止剤、剥離促進剤、マット剤などの添加剤を加えることもできる。
リターデーション調整剤としては、特に制限はなく、可塑剤、紫外線吸収剤、酸化防止剤、マット剤などの添加剤がリターデーション調整剤としても用いられる場合、これらの添加剤は本発明におけるリターデーション調整剤に含まれる。
本発明ではリターデーション値を発現するために、棒状又は円盤状化合物からなるものを挙げることができる。上記棒状又は円盤状化合物としては、少なくとも二つの芳香族環を有する化合物をリターデーション発現剤として好ましく用いることができる。
芳香族性ヘテロ環は一般に、最多の二重結合を有する。ヘテロ原子としては、窒素原子、酸素原子及び硫黄原子が好ましく、窒素原子が特に好ましい。芳香族性ヘテロ環の例には、フラン環、チオフェン環、ピロール環、オキサゾール環、イソオキサゾール環、チアゾール環、イソチアゾール環、イミダゾール環、ピラゾール環、フラザン環、トリアゾール環、ピラン環、ピリジン環、ピリダジン環、ピリミジン環、ピラジン環及び1,3,5-トリアジン環が含まれる。
c2:-CO-NH-
c3:-アルキレン-O-
c4:-NH-CO-NH-
c5:-NH-CO-O-
c6:-O-CO-O-
c7:-O-アルキレン-O-
c8:-CO-アルケニレン-
c9:-CO-アルケニレン-NH-
c10:-CO-アルケニレン-O-
c11:-アルキレン-CO-O-アルキレン-O-CO-アルキレン-
c12:-O-アルキレン-CO-O-アルキレン-O-CO-アルキレン-O-
c13:-O-CO-アルキレン-CO-O-
c14:-NH-CO-アルケニレン-
c15:-O-CO-アルケニレン-
芳香族環及び連結基は、置換基を有していてもよい。
置換基の例には、ハロゲン原子、アルコキシ基(例えば、メトキシ基、エトキシ基)及びアシルオキシ基(例えば、アクリロイルオキシ基、メタクリロイルオキシ基)が含まれる。
アルケニル基は置換基を有していてもよい。置換基の例には、前述のアルキル基の置換基と同様である。
上記一般式(11)において、Ar1及びAr2は、それぞれ独立に、芳香族基である。
上記一般式(12)において、Ar1及びAr2は、それぞれ独立に、芳香族基である。芳香族基の定義及び例は、一般式(12)のAr1及びAr2と同様である。
本発明においてはセルロースエステル溶液に、偏光板又は液晶等の劣化防止の観点から、紫外線吸収剤が好ましく用いられる。紫外線吸収剤としては、波長370nm以下の紫外線の吸収能に優れ、かつ良好な液晶表示性の観点から、波長400nm以上の可視光の吸収が少ないものが好ましく用いられる。本発明に好ましく用いられる紫外線吸収剤の具体例としては、例えばヒンダードフェノール系化合物、ヒドロキシベンゾフェノン系化合物、ベンゾトリアゾール系化合物、サリチル酸エステル系化合物、ベンゾフェノン系化合物、シアノアクリレート系化合物、ニッケル錯塩系化合物などが挙げられる。
本発明のフィルムには、剥離促進剤を含有することが、より剥離性と高める観点から好ましい。剥離促進剤は、例えば、0.001~1質量%の割合で含めることができ、0.5質量%以下の添加であれば剥離剤のフィルムからの分離等が発生し難いため好ましく、0.005質量%以上であれば所望の剥離低減効果を得ることができるため好ましいため、0.005~0.5質量%の割合で含めることが好ましく、0.01~0.3質量%の割合で含めることがより好ましい。剥離促進剤としては、公知のものが採用でき、有機、無機の酸性化合物、界面活性剤、キレート剤等を使用することができる。中でも、多価カルボン酸及びそのエステルが効果的であり、特に、クエン酸のエチルエステル類が効果的に使用することができる。
特に本発明のフィルムには、ハンドリングされる際に、傷が付いたり搬送性が悪化することを防止するために、微粒子を添加することが一般に行われる。それらは、マット剤、ブロッキング防止剤あるいはキシミ防止剤と称されて、従来から利用されている。それらは、前述の機能を呈する素材であれば特に限定されず、無機化合物のマット剤であっても、有機化合物のマット剤であってもよい。
前記二酸化ケイ素の微粒子としては、例えば、アエロジルR972、R974、R812、200、300、R202、OX50、TT600(以上日本アエロジル(株)製)等の商品名を有する市販品が使用できる。前記酸化ジルコニウムの微粒子としては、例えば、アエロジルR976及びR812(以上日本アエロジル(株)製)等の商品名で市販されているものが使用できる。
(リターデーション)
本発明のフィルムは、上記で定義される面内リターデーション値Ro(590)が40~70nmの範囲内であり、上記で定義される厚さ方向のリターデーション値Rt(590)が100~200nmの範囲内であるように調整することが好ましい。
本発明のセルロースエステルフィルムは、ヘイズが0.5%未満であることが好ましく、0.3%未満であることがより好ましい。ヘイズを0.5%未満とすることにより、フィルムの透明性がより高くなり、セルロースエステルフィルムとしてより用いやすくなるという利点がある。
本発明のセルロースエステルフィルムは、弾性率が3.5以上が好ましく、4.0以上がより好ましい。弾性率を4.0以上にすることにより、耐久時の偏光板収縮を抑制することができる。
セルロースエステルフィルムを、80℃、90%RHの高温高湿雰囲気下で1000時間放置後、目視観察でセルロースエステルフィルム表面のブリードアウト(結晶析出)の有無を確認する。
本発明のセルロースエステルフィルムのフィルムコントラスト値は、フィルムの配向が均一なほどフィルムコントラスト値は高くなる。上記フィルムコントラスト値は、好ましくは5000以上であり、より好ましくは7000以上10000以下であり、更に好ましくは9000以上10000以下である。
本発明の偏光板を60℃、90%RHで250時間の処理を行い、その後、23℃、55%RHの部屋で24時間調湿して、偏光板の平面性を確認する。
本発明の偏光板を20cm×20cmの大きさの正方形に断裁し、アクリル系接着剤を用いてガラス基板と貼り合わせる。次いで、貼り合わせた偏光板を角の部分から5Nの強さでガラスから剥がし、完全に剥離されなかった偏光板の枚数を数えることで、リワーク性を評価した。
本発明の液晶表示装置のバックライトを1時間連続点灯した後、測定を行った。測定にはELDIM社製EZ-Contrast160Dを用いて、液晶表示装置で白表示と黒表示の表示画面の法線方向からの輝度を測定し、その比を正面コントラストとし、評価した。
上記正面コントラストの値が、1000以上であれば実用上問題なく、1100以上であることがより好ましい。
本発明のフィルムの膜厚は10~35μmである。さらに、20~35μmであることがより好ましい。10μm以上とすることにより、フィルムの腰が保たれるため好ましい。20μm以上とすることにより、フィルムの平面性が保たれやすく、また、35μm以下とすることにより、フィルムの透明性に有利である。
本発明のセルロースエステルフィルムは、当該フィルムの長さが、5000~10000mの範囲内であり、当該フィルムの幅が1.9~2.5mの範囲内であることが好ましい。
本発明のフィルムの製造方法は、ポリマーを有機溶剤に溶解させてドープを調製する工程(ドープ調製工程)と、前記ドープを濾過する工程(濾過工程)と、ドープを支持体上に流延しする工程(流延工程)、得られたフィルムを乾燥する工程(乾燥工程)と、得られたフィルム延伸する工程(延伸工程)を少なくとも含み、その他必要に応じた工程を含むものである。
詳しくは、本発明に係る製造方法では、ソルベントキャスト法によりセルロースエステルを有機溶媒に溶解した溶液(ドープ)を用いて本発明のフィルムを製造する。
容器は攪拌できるように構成されている必要がある。窒素ガス等の不活性気体を注入して容器を加圧することができる。また、加熱による溶媒の蒸気圧の上昇を利用してもよい。
あるいは、容器を密閉後、各成分を圧力下で添加してもよい。
セルロースエステル溶液の濾過については公知の様々な濾過装置を用いることができる。すなわち、濾過機としては大別すると連続濾過機と回分加圧濾過機に分けることができ、連続濾過機としてはベルト式、多重円板式、スクリュウ圧搾式、フィルタプレス式などに分けることができ、回分加圧濾過機としてはリーフ式、キャンドル式などが挙げることができる。
本発明のフィルムの製造方法において用いられる溶液流延方法は、少量で行う場合はガラスや金属の容器にドープを調製し、濾過を行った後に、ドープを平滑性の高い、ガラス板や金属板などの支持体上に小型ダイやドクターブレードなどを用いて所望の膜厚に流延する。流延後、一次乾燥を行い、支持体から剥離し、必要に応じて枠張りし、後乾燥を行う。
さらに本発明に係るセルロースエステル溶液は、他の機能層(例えば、接着層、染料層、帯電防止層、アンチハレーション層、UV吸収層、偏光層など)を同時に流延することも実施しうる。本発明のフィルムを製造する方法としては、製膜が同時又は逐次での多層流延製膜であることが好ましい。
ドラムやベルト上で乾燥され、剥離されたウェブの乾燥方法について述べる。ドラムやベルトが1周する直前の剥離位置で剥離されたウェブは、千鳥状に配置されたロ-ル群に交互に通して搬送する方法や剥離されたウェブの両端をクリップ等で把持させて非接触的に搬送する方法などにより搬送される。
ここで、Mはウェブの任意時点での質量、NはMを測定したウェブを110℃で3時間乾燥させた時の質量である。
本発明においては、フィルム性能を向上させるために積極的に幅方向に延伸してもよく、例えば、特開昭62-115035号公報、特開平4-152125号、同4-284211号公報、同4-298310号公報、同11-48271号公報などに記載されている方法を適用できる。フィルムの延伸は、一般にはTg(ガラス転移温度)よりもさらに10~20℃高い温度で行う場合が多いが、本発明のフィルムはガラス転移温度が高く、ガラス転移温度以上に加熱することでポリマーの分解が開始する場合がある。このような場合、本発明では特に本発明のフィルムの乾燥中の処理で延伸することが有効である。
つまり溶媒を含んだ見かけのガラス転移温度が低い状態で延伸を行うことでポリマーの分解を起こさない温度で延伸することができる。その延伸方法としては、例えば、剥ぎ取り時の場合フィルムの搬送ローラーの速度を調節して、フィルムの剥ぎ取り速度よりもフィルムの巻き取り速度の方を速くするとフィルムは延伸される。また、剥ぎ取り後の乾燥時の場合、搬送方向手前側の搬送ローラーの搬送速度に対して搬送先の搬送ローラーの搬送速度を速くすることでフィルムは延伸される。また、フィルムの巾をテンターで保持しながら搬送して、テンターの巾を徐々に広げることでフィルムを幅方向に延伸できる。
また、フィルムの長手方向(MD方向)延伸倍率は1.01~1.2倍であることが好ましく、より好ましくは1.01~1.1倍である。
[偏光板]
本発明のセルロースエステルフィルムは、光学発現性が高いため、位相差フィルムとして偏光板用保護フィルムに好ましく用いられる。偏光板は、偏光子の少なくとも一方の面に保護フィルムを貼り合わせ積層することによって形成される。偏光子は従来から公知のものを用いることができ、例えば、ポリビニルアルコールフィルムのような親水性ポリマーフィルムを、沃素のような二色性染料で処理して延伸したものである。セルロースエステルフィルムと偏光子との貼り合わせは、特に限定はないが、水溶性ポリマーの水溶液からなる接着剤により行うことができる。この水溶性ポリマー接着剤は完全鹸化型のポリビニルアルコール水溶液が好ましく用いられる。
本発明のセルロースエステルフィルム、当該フィルムを用いた偏光板は、様々な表示モードの液晶セル、液晶表示装置に用いることができる。TN(Twisted Nematic)、IPS(In-Plane Switching)、FLC(Ferroelectric Liquid Crystal)、AFLC(Anti-ferroelectric Liquid Crystal)、OCB(Optically Compensatory Bend)、STN(Supper Twisted Nematic)、VA(Vertically Aligned)及びHAN(Hybrid Aligned Nematic)のような様々な表示モードが提案されている。
図1に示す製造装置を用いて、下記手順で、セルロースエステルフィルム1~18を製造した。
(ドープ液)
セルロースエステル(セルロースアセテートプロピオネート アセチル基置換度0.1、プロピオニル基1.5): 90質量部
糖エステル化合物5: 10質量部
メチレンクロライド: 300質量部
エタノール: 40質量部
上記ドープ液の構成成分を主ドープ仕込み釜1に投入し、加熱し、撹拌しながら、完全に溶解し、主濾過器4(安積濾紙(株)製:安積濾紙No.24)を使用して濾過し、ドープを調製した。次いで、ドープ濾過器5(日本精線(株)製:ファインメットNF)でドープを濾過した。
脂環式構造を有する樹脂(日本ゼオン社製、ゼオノア1060R、吸水率0.01%)100部を二軸押出機で混練してストランド状に押し出し、ペレタイザーで切断してペレットを製造した。このペレットを原料として、射出成形機を用いて、膜厚20μmのフィルムを成形した。
樹脂を環状オレフィン樹脂(COP)(ARTON、JSR株式会社製)に変更した以外は、フィルム19と同様にして、フィルム20を作製した。
(コア層用セルロースエステルドープの調製)
セルロースエステル10: 90質量部
ポリエステル1: 10質量部
ジクロロメタン: 406質量部
メタノール: 61質量部
(スキンB層用セルロースエステルドープの調製)
セルロースエステル13: 96質量部
化合物1: 4質量部
マット剤:平均粒子径16nmのシリカ粒子(aerosil R972 日本アエロジル(株)製): 0.12質量部
剥離促進剤:クエン酸の部分エチルエステル化合物: 0.05質量部
ジクロロメタン: 406質量部
メタノール: 61質量部
(スキンA層用セルロースエステルドープの調製)
セルロースエステル13: 96質量部
化合物1: 4質量部
マット剤:平均粒子径16nmのシリカ粒子(aerosil R972 日本アエロジル(株)製): 0.12質量部
ジクロロメタン: 406質量部
メタノール: 61質量部
ドープを流延する際には、図2に示すように、走行する流延バンド上に共流延ダイ10から上記3種類のドープを共に流延した。ここで、各ドープの流延量を調整することによりコア層を最も厚くし、結果的に延伸後のフィルムの膜厚が下記表7の値となるように同時多層流延を行い流延膜を形成させた。
下記表7に記載のように、樹脂、添加剤、膜厚を変更した以外はセルロースエステルフィルム21と同様にして、各実施例のセルロースエステルフィルムを得た。
得られたセルロースエステルフィルム1~18、21~27及びフィルム19、20について以下の評価を行った。
測定は、自動複屈折計KOBRA・WR(王子計測器(株)製)を用いて、23℃、55%RHの環境下で波長が590nmにおいて、行われ、得られた測定値を下式(a)、(b)に代入して、面内リターデーションRo、厚み方向リターデーションRtを求めた。
式(b)厚み方向リターデーション Rt=((nx+ny)/2-nz)×d
(ヘイズ)
濁度計(NDH2000,日本電色工業(株))を用いて、23℃、55%RHの環境下24時間放置したフィルムにおいて、同環境下、フィルムのヘイズ(面品質ヘイズ%)測定を行った。
本発明において弾性率は、23℃、55%RHの環境下で試料を24時間調湿し、JIS K7127に記載の方法に準じて、同環境下引っ張り試験器オリエンテック(株)製テンシロンRTA-100を使用し、試験片の形状は1号形試験片で、試験速度は10mm/分の条件で、TD方向の弾性率を測定した。
◎:4.0以上
○:3.5以上4.0未満
△:3.0以上3.5未満
×:3.0未満
弾性率は○レベル以上であることが好ましく、◎レベルであることが特に好ましい。
セルロースエステルフィルムを、80℃、90%RHの高温高湿雰囲気下で1000時間放置後、セルロースエステルフィルム表面のブリードアウト(結晶析出)の有無を目視観察を行った。
◎:表面にブリードアウトの発生が全く認められない
○:表面で、部分的なブリードアウトが僅かに認められる
△:表面で、全面に亘りブリードアウトが僅かに認められる
×:表面で、全面に亘り明確なブリードアウトが認められる
ブリードアウトは○レベル以上であることが好ましく、◎レベルであることが特に好ましい。
テーブル上に、下から順に直下型蛍光管バックライト光源、上側偏光板、試料、下側偏光板を各面が水平になるように設置する。この時、試料と上側偏光板は回転可能とする。
光源から出射し、上側偏光板、試料、下側偏光板と順に透過した光を垂直方向からBM-5A(TOPCON製)を用いて輝度を測定した。測定は、まず試料のない状態で上側偏光板を回転させて最も輝度が暗くなる位置に合わせる(クロスニコルの状態)。試料を挿入し、クロスニコル下で試料を回転させて最小となる輝度を測定する。次に上側偏光板と下側偏光板の2枚の偏光板を平行ニコル配置にして、試料を回転させて最大となる輝度を測定する。
◎:9000以上10000未満
○:7000以上9000未満
△:5000以上7000未満
×:5000未満
フィルムコントラストは○レベル以上であることが好ましく、◎レベルであることが特に好ましい。
<偏光板の作製>
得られたセルロースエステルフィルム1~18、21~27を用い、下記方法により偏光板を作製した。
本発明の偏光板を60℃、90%RHで250時間の処理を行い、その後、23℃、55%RHの部屋で24時間調湿して、偏光板の平面性を確認した。
◎:うねりやしわがない
○:うねりやしわがほとんどない
△:うねりやしわがわずかに見られる
×:うねりやしわが見られる
平面性は△レベル以上であれば実用上問題ないが、○レベルであることが好ましく、◎レベルであることが特に好ましい。
23℃、55%RHの雰囲気下、作製した偏光板を20cm×20cmの大きさの正方形に断裁し、アクリル系接着剤を用いてガラス基板と貼り合わせる。次いで、貼り合わせた偏光板を角の部分から5Nの強さでガラスから剥がす。この作業を1種類のサンプルについて100枚の偏光板で行い、偏光板に裂け目が入って、完全に剥離されなかった偏光板の枚数を数えた。リワーク性は以下の基準でランク付けした。
◎:0~5枚
○:6~10枚
△:11~15枚
×:16枚以上
リワーク性は△レベル以上であれば実用上問題ないが、○レベル以上であることが好ましく、◎レベルであることが特に好ましい。
<液晶表示装置の作製>
実施例2で得られた偏光板を用い視野角測定を行う液晶パネルを以下のようにして作製し、液晶表示装置としての特性を評価した。
〔正面コントラスト〕
液晶表示装置のコントラスト特性の評価をELDIM社製EZ-contrast160Dを用い、液晶表示装置で白表示と黒表示の表示画面の法線方向からの輝度を測定し、その比を正面コントラストとした。
以下のように、コントラストの評価ランクを決定した。
◎:1100~1200以上
○:1000~1100未満
×:1000未満
○以上であれば、実用上、問題ない。
2 ドープ送液ポンプ、
3 ドープ静置釜、
4 主濾過器、
5 ドープ濾過器、
6 インライン添加液釜、
7 インライン添加液循環濾過器、
8 インライン添加液送液濾過器、
9 インライン添加液送液ポンプ、
100 スタティックミキサー、
101 ステンレスバンド、
102 剥離ロール、
103 フィルム、
104 テンター・乾燥装置、
105 ロール搬送・乾燥装置(乾燥ゾーン)、
106 フィルム巻き取り装置、
10 共流延ダイ、
11 口金部分、
13、15 表層用スリット、
14 基層用スリット、
16 金属支持体、
17、19 表層用ドープ、
18 基層用ドープ、
20 多層構造ウェブ、
21 スキンB層、
22 コア層、
23 スキンA層。
Claims (8)
- 炭素数が3~4のアシル基、又は、炭素数が2のアシル基および炭素数3~4のアシル基で置換され、かつ該アシル基の総置換度は1.0以上、2.0未満であり、重量平均分子量が150000以下を満たすセルロースエステル、及び、
ピラノース構造またはフラノース構造の少なくとも1種の糖単位構造を1個以上12個以下有し、かつ、前記糖単位構造における平均置換割合が35%~75%である糖エステル化合物を含有し、
更に、膜厚が10~35μmであることを特徴とするセルロースエステルフィルム。 - 前記糖エステル化合物が置換度の異なる混合物であることを特徴とする請求項1または2に記載のセルロースエステルフィルム。
- 前記セルロースエステルの炭素数3以上のアシル基の置換度が、0.9以上2.0未満であることを特徴とする、請求項1~3のいずれか1項に記載のセルロースエステルフィルム。
- 前記セルロースエステルの前記アシル基の総炭素数が4.4を超えていることを特徴とする、請求項1~4のいずれか1項に記載のセルロースエステルフィルム。
- 前記セルロースエステルフィルムの面内リターデーション値Ro(590)が40~70nmの範囲内であり、厚さ方向のリターデーション値Rt(590)が100~200nmの範囲内であり、フィルムコントラストが7000~10000であることを特徴とする請求項1~5のいずれか一項に記載のセルロースエステルフィルム。
- 請求項1~6のいずれか一項に記載のセルロースエステルフィルムが備えられたことを特徴とする偏光板。
- 請求項1~6のいずれか一項に記載のセルロースエステルフィルムが備えられたことを特徴とする液晶表示装置。
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KR1020137023600A KR101516514B1 (ko) | 2011-03-11 | 2012-03-02 | 셀룰로오스 에스테르 필름, 그것이 구비된 편광판 및 액정 표시 장치 |
JP2013504655A JP5742930B2 (ja) | 2011-03-11 | 2012-03-02 | セルロースエステルフィルム、それが具備された偏光板及び液晶表示装置 |
US14/003,627 US9256016B2 (en) | 2011-03-11 | 2012-03-02 | Cellulose ester films, polarizing plates and liquid crystal displays equipped therewith |
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JP6393651B2 (ja) * | 2015-03-31 | 2018-09-19 | 富士フイルム株式会社 | セルロースアシレートフィルムの製造方法 |
TW202336123A (zh) * | 2021-11-12 | 2023-09-16 | 美商伊士曼化學公司 | 淡水可生物降解之混合酯纖維素酯 |
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WO2007125765A1 (ja) * | 2006-04-25 | 2007-11-08 | Konica Minolta Opto, Inc. | 偏光板保護フィルム及びその製造方法、偏光板、液晶表示装置 |
JP2007304376A (ja) * | 2006-05-12 | 2007-11-22 | Konica Minolta Opto Inc | 偏光板保護フィルム、偏光板保護フィルムの製造方法、偏光板及び液晶表示装置 |
WO2008062610A1 (fr) * | 2006-11-25 | 2008-05-29 | Konica Minolta Opto, Inc. | Procédé de fabrication de film optique, film d'ester de cellulose, polariseur et dispositif d'affichage à cristaux liquides |
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US20090096962A1 (en) * | 2007-05-14 | 2009-04-16 | Eastman Chemical Company | Cellulose Esters with High Hyrdoxyl Content and Their Use in Liquid Crystal Displays |
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JP5218411B2 (ja) | 2007-09-06 | 2013-06-26 | コニカミノルタアドバンストレイヤー株式会社 | 光学フィルム、偏光板及び液晶表示装置 |
US20110058127A1 (en) * | 2009-03-02 | 2011-03-10 | Fujifilm Corporation | Optical compensation sheet, polarizing plate, liquid crystal display and method of manufacturing optical compensation sheet |
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JP2005515285A (ja) * | 2002-01-16 | 2005-05-26 | イーストマン ケミカル カンパニー | ポリマー用可塑剤としての新規炭水化物エステル及びポリオールエステル、そのような可塑剤を含む組成物及び製品並びにこれらの使用方法 |
WO2007125765A1 (ja) * | 2006-04-25 | 2007-11-08 | Konica Minolta Opto, Inc. | 偏光板保護フィルム及びその製造方法、偏光板、液晶表示装置 |
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US9256016B2 (en) | 2016-02-09 |
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JPWO2012124514A1 (ja) | 2014-07-17 |
KR101516514B1 (ko) | 2015-05-04 |
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