WO2016113953A1 - 位相差フィルム、偏光板及び垂直配向型液晶表示装置 - Google Patents
位相差フィルム、偏光板及び垂直配向型液晶表示装置 Download PDFInfo
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- WO2016113953A1 WO2016113953A1 PCT/JP2015/077239 JP2015077239W WO2016113953A1 WO 2016113953 A1 WO2016113953 A1 WO 2016113953A1 JP 2015077239 W JP2015077239 W JP 2015077239W WO 2016113953 A1 WO2016113953 A1 WO 2016113953A1
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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
- G02F1/13363—Birefringent elements, e.g. for optical compensation
Definitions
- the present invention relates to a retardation film, a polarizing plate having a retardation film, and a vertical alignment type liquid crystal display device.
- the conventional retardation film has insufficient retardation, and it has been difficult to reduce the thickness of the liquid crystal display device in recent years while maintaining a desired retardation.
- a retardation increasing agent In order to reduce the thickness of the retardation film while maintaining the retardation satisfying the display performance, it is known to use a retardation increasing agent.
- Such retardation increasing agents for retardation films are described in Patent Document 3, for example.
- the present invention has been made in view of the above points, a retardation film capable of suppressing retardation fluctuation due to moisture absorption while maintaining wet heat durability with a thin film configuration, and a polarizing plate having the retardation film
- An object of the present invention is to provide a vertical alignment type liquid crystal display device.
- the photoelastic coefficient is in the range of 7.0 ⁇ 10 ⁇ 13 to 25.0 ⁇ 10 ⁇ 13 cm 2 / dyn,
- the in-plane phase difference Ro is 10 to 150 nm
- the thickness direction retardation Rth is 30 to 400 nm
- Formula (1) 1.8 ⁇ X + Y ⁇ 2.9
- Formula (2) 0.03 ⁇ Y ⁇ 0.8
- X represents the degree of substitution of the acetyl group
- Y represents the degree of substitution of the butyryl group.
- retardation film as described in 1 above, wherein the retardation increasing agent is a nitrogen-containing heterocyclic compound and is a compound having a pyrrole ring, a pyrazole ring, a triazole ring or an imidazole ring.
- A represents a pyrazole ring
- Ar 1 and Ar 2 each represents an aromatic hydrocarbon ring or an aromatic heterocyclic ring, and may have a substituent.
- R 1 represents a hydrogen atom, an alkyl group, an acyl group; A group, a sulfonyl group, an alkyloxycarbonyl group or an aryloxycarbonyl group, q represents an integer of 1 or 2, and n and m represent an integer of 1 to 3.
- a polarizing plate comprising the retardation film according to any one of 1 to 3.
- a vertical alignment type liquid crystal display device comprising the polarizing plate described in 4 above.
- a retardation film capable of suppressing retardation fluctuation due to moisture absorption while maintaining wet heat durability with a thin film configuration, a polarizing plate having the retardation film, and a vertical alignment type liquid crystal display device Can be provided.
- the retardation film is configured as follows in order to suppress retardation fluctuation due to moisture absorption while maintaining wet heat durability with the thin film configuration. That is, the retardation film of this embodiment contains a cellulose ester and a retardation increasing agent, and has a photoelastic coefficient of 7.0 ⁇ 10 at a measurement wavelength of 590 nm under an environment of a temperature of 23 ° C. and a relative humidity of 55% RH.
- the cellulose ester has a degree of substitution of 1.8 ⁇ X + Y ⁇ 2.9 and 0.03 ⁇ Y ⁇ 0.8 (X represents the degree of substitution of the acetyl group, and Y represents the degree of substitution of the butyryl group). Satisfy both.
- the reason why the retardation varies due to moisture absorption in the conventional retardation film is estimated as follows. That is, because the cellulose ester has a large number of acyl group carbon atoms, the distance between the resins becomes longer, voids are formed, and it is difficult for water to enter once here, or the carbonyl group present in the acyl substituent of the cellulose acylate resin. It is assumed that the birefringence changes due to the coordination of water molecules.
- a cellulose ester (cellulose acetate butyrate) that satisfies the above-described predetermined relationship with respect to the substitution degree X of the acetyl group and the substitution degree Y of the butyryl group is used, and a compound (retardation increasing agent) is mixed with the cellulose ester.
- the compound cuts the interaction between the carbonyl group or hydrogen atom of cellulose and water, or the compound is coordinated to the side chain, carbonyl group or hydrogen atom of the cellulose ester. It is considered that retardation fluctuation due to moisture absorption is suppressed.
- the retardation film contracts and expands due to external force generated by the contraction and expansion due to moisture absorption of the polarizer of the polarizing plate, or the residual stress after stretching.
- the occurrence of birefringence is small even if there is contraction due to. Thereby, it is considered that the retardation fluctuation due to moisture absorption of the retardation film could be further suppressed.
- the retardation increasing agent for the retardation film is preferably a nitrogen-containing heterocyclic compound, and is preferably a compound having a pyrrole ring, a pyrazole ring, a triazole ring or an imidazole ring.
- the nitrogen-containing heterocyclic compound is preferably a compound having a structure represented by the general formula (3). According to these configurations, it is possible to more effectively suppress retardation fluctuation due to moisture absorption, and display quality is improved.
- the retardation film having the above structure was provided on the polarizing plate. Further, the polarizing plate was mounted on a vertical alignment type liquid crystal display device. According to these configurations, in the polarizing plate and the vertical alignment type liquid crystal display device, it is possible to suppress retardation fluctuation due to moisture absorption of the retardation film, so that the change in color due to color unevenness of the display panel can be improved. Can do.
- FIG. 1 is a cross-sectional view illustrating a schematic configuration of a vertical alignment (VA) liquid crystal display device according to the present embodiment.
- the vertical alignment type liquid crystal display device 1 includes a liquid crystal display panel 2 and a backlight 3.
- the backlight 3 is a light source for illuminating the liquid crystal display panel 2.
- the liquid crystal display panel 2 is configured by disposing polarizing plates 5 and 6 on both front and back sides of the liquid crystal cell 4, respectively.
- the liquid crystal cell 4 is formed by sandwiching a liquid crystal layer between a pair of transparent substrates (not shown).
- a vertical alignment type liquid crystal cell adopting a color filter on array (COA) method can be used, but the color filter is disposed on a transparent substrate on the viewing side (front side) with respect to the liquid crystal layer.
- a liquid crystal cell may be used.
- a polarizing plate 5 is attached to one surface of the viewing side (front surface side) of the liquid crystal cell 4 via an adhesive layer 7.
- a polarizing plate 6 is attached to one surface of the backlight 3 side (back surface side) of the liquid crystal cell 4 via an adhesive layer 8.
- the polarizing plate 5 includes a polarizer 11 and optical films 12 and 13.
- the polarizer 11 transmits predetermined linearly polarized light.
- the optical film 12 is a protective film disposed on the viewing side (surface side) of the polarizer 11.
- the optical film 13 is disposed on the backlight 3 side (back side) of the polarizer 11.
- the polarizing plate 6 includes a polarizer 14 and optical films 15 and 16.
- the polarizer 14 transmits predetermined linearly polarized light.
- the optical film 15 is disposed on the viewing side of the polarizer 14.
- the optical film 16 is disposed on the backlight 3 side of the polarizer 14. Note that the viewing-side optical film 15 may be omitted, and the polarizer 14 may be in direct contact with the adhesive layer 8.
- the polarizer 11 and the polarizer 14 are disposed so as to be in a crossed Nicols state.
- the retardation film of this embodiment can be used as the optical film 13 of the polarizing plate 5, for example.
- the retardation film of this embodiment contains a cellulose ester and a retardation increasing agent, and has a photoelastic coefficient of 7.0 ⁇ 10 ⁇ 13 at a measurement wavelength of 590 nm under an environment of a temperature of 23 ° C. and a relative humidity of 55% RH. Is in the range of 25.0 ⁇ 10 ⁇ 13 cm 2 / dyn, the in-plane phase difference Ro is 10 to 150 nm, the thickness direction phase difference Rth is 30 to 400 nm, and the film thickness is 20 to 45 ⁇ m. Details of these elements will be described in the embodiments described later.
- Photoelasticity refers to a phenomenon that exhibits optical anisotropy and exhibits birefringence when an external force is applied to an isotropic substance to cause internal stress.
- the stress (force per unit area) acting on the substance is ⁇ and the birefringence is ⁇ n
- C is the photoelastic coefficient.
- the photoelastic coefficient C can be adjusted by adjusting the type and content of the resin and additive constituting the retardation film.
- the cellulose ester consists of cellulose acetate butyrate.
- Cellulose acetate butyrate preferably satisfies both the following (1) and (2) when the substitution degree of the acetyl group is X and the substitution degree of the butyryl group is Y.
- the degree of substitution can be measured according to ASTM-D817-96.
- Formula (1) 1.8 ⁇ X + Y ⁇ 2.9
- Formula (2) 0.03 ⁇ Y ⁇ 0.8
- the cellulose ester can be produced by a known method.
- examples of cellulose as a raw material for cellulose ester include cotton linter, wood pulp, kenaf and the like, but are not particularly limited thereto.
- the cellulose ester obtained from them can be mixed and used for each arbitrary ratio.
- the retardation increasing agent of this embodiment is a retardation film in which the retardation value Rth (measurement wavelength 590 nm) in the thickness direction of the retardation film containing 3 parts by mass of the compound with respect to 100 parts by mass of the cellulose ester is not added.
- the retardation increasing agent is not particularly limited.
- a discotic compound having an aromatic ring described in paragraphs [0143] to [0179] of JP-A-2006-113239 which is well known in the art (1,3 , 5-triazine compounds, etc.)
- epoxy ester compounds described in paragraphs [0022] to [0028] of JP 2011-140637 A polyester compounds described in paragraphs [0044] to [0058] of WO 2012/014571, etc. are used. be able to.
- the retardation increasing agent properties required for the retardation increasing agent include excellent compatibility with the cellulose acetate butyrate resin, excellent retardation when the film is thinned, excellent precipitation resistance, and high humidity. In the bottom, it is excellent in resistance to fluctuations in phase difference value due to the entry and exit of moisture. From such a viewpoint, it is preferable to use the following nitrogen-containing heterocyclic compound as a retardation increasing agent.
- the retardation increasing agent of the present embodiment is preferably a nitrogen-containing heterocyclic compound having a structure represented by the following general formula (4).
- the nitrogen-containing heterocyclic compound controls the hydrogen bonding property of the cellulose ester by CH / ⁇ interaction with the cellulose ester, and one compound has both the functions of a phase difference increasing agent and a wavelength dispersion adjusting agent.
- it has excellent compatibility when combined with a cellulose ester, and there is little generation of fine foreign matters and precipitates during the production process.
- 1,3,5-triazine-based phase difference increasing agents and the like have a weak CH / ⁇ interaction, so they are slightly inferior in compatibility and easily generate foreign matters, and have a high elution property in a saponification solution. It is in.
- CH / ⁇ interaction refers to the compatibility of hydrogen bond donating sites such as cellulose esters (for example, hydrogen atoms of hydroxy groups) and hydrogen bond accepting sites (for example, carbonyl oxygen atoms of ester groups) with additives. This is a bond interaction between the hydrogen bonding site present in the main chain or side chain of the resin and the ⁇ electron of the aromatic compound of the additive. Due to this CH / ⁇ interaction, the compatibility is excellent.
- NICS Nucleus-Independent Chemical Shift
- This NICS value is an index used for quantification of aromaticity due to magnetic properties. If the ring is aromatic, the ring center is strongly shielded by the ring current effect, and conversely if the ring is antiaromatic. Anti-shielding (J. Am. Chem. Soc. 1996, 118, 6317). Depending on the magnitude of the NICS value, the strength of the ring current, that is, the degree of contribution of ⁇ electrons to the aromaticity of the ring can be determined. Specifically, the NICS value represents the chemical shift (calculated value) of a virtual lithium ion arranged directly at the center of the ring, and the larger the value, the stronger the ⁇ property.
- 5-membered aromatic heterocycles such as ring (-12.42), pyrazole ring (-13.82), or imidazole ring (-13.28), triazole ring (-13.18), oxadiazole ring (
- a 6-membered aromatic hydrocarbon ring such as -12.44) or a thiazole ring (-12.82) has a larger NICS value (the NICS value is shown in parentheses).
- a pyrrole ring, a pyrazole ring, a triazole ring or an imidazole ring is preferable because of its excellent compatibility with the cellulose ester.
- the nitrogen-containing heterocyclic compound according to this embodiment is preferably a nitrogen-containing heterocyclic compound having a pyrrole ring, a pyrazole ring, a triazole ring or an imidazole ring, and has a structure represented by the following general formula (4).
- nitrogen heterocyclic compounds nitrogen-containing heterocyclic compounds having the specific ring structure are preferred.
- the compound having the structure represented by the following general formula (4) is used together with cellulose acetate, so that when a polarizing plate is used in a liquid crystal display device, the occurrence of retardation fluctuation due to environmental humidity fluctuation is suppressed, and contrast reduction and color are suppressed. Generation of unevenness can be suppressed. Furthermore, it functions as a retardation increasing agent showing forward wavelength dispersibility by appropriately adjusting the type and amount of the nitrogen-containing heterocyclic compound.
- the molecular weight is preferably in the range of 100 to 800, and more preferably in the range of 250 to 450.
- a 1 , A 2 and B are each independently an alkyl group (methyl group, ethyl group, n-propyl group, isopropyl group, tert-butyl group, n-octyl group, 2-ethylhexyl).
- Group a cycloalkyl group (cyclohexyl group, cyclopentyl group, 4-n-dodecylcyclohexyl group, etc.), an aromatic hydrocarbon ring or an aromatic heterocyclic ring.
- an aromatic hydrocarbon ring or an aromatic heterocyclic ring is preferable, and a 5-membered or 6-membered aromatic hydrocarbon ring or aromatic heterocyclic ring is particularly preferable.
- the structure of the 5-membered or 6-membered aromatic hydrocarbon ring or aromatic heterocyclic ring is not limited, but for example, benzene ring, pyrrole ring, pyrazole ring, imidazole ring, 1,2,3-triazole ring, 1,2, Examples include 4-triazole ring, tetrazole ring, furan ring, oxazole ring, isoxazole ring, oxadiazole ring, isoxadiazole ring, thiophene ring, thiazole ring, isothiazole ring, thiadiazole ring, isothiadiazole ring and the like.
- the 5-membered or 6-membered aromatic hydrocarbon ring or aromatic heterocyclic ring represented by A 1 , A 2 and B may have a substituent.
- substituents include a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom, etc.), alkyl group (methyl group, ethyl group, n-propyl group, isopropyl group, tert-butyl group, n-octyl group).
- cycloalkyl group (cyclohexyl group, cyclopentyl group, 4-n-dodecylcyclohexyl group, etc.), alkenyl group (vinyl group, allyl group, etc.), cycloalkenyl group (2-cyclopenten-1-yl) , 2-cyclohexen-1-yl group, etc.), alkynyl groups (ethynyl group, propargyl group, etc.), aromatic hydrocarbon ring groups (phenyl group, p-tolyl group, naphthyl group, etc.), aromatic heterocyclic groups (2 -Pyrrole group, 2-furyl group, 2-thienyl group, pyrrole group, imidazolyl group, oxazolyl group, thiazolyl group, benzoy Dazolyl group, benzoxazolyl group, 2-benzothiazolyl group, pyrazolin
- Aryloxy group (phenoxy group, 2-methylphenoxy group, 4-tert-butylphenoxy group) 3-nitrophenoxy group, 2-tetradecanoylaminophenoxy group, etc.
- acyloxy groups (formyloxy group, acetyloxy group, pivaloyloxy group, stearoyloxy group, benzoyloxy group, p-methoxyphenylcarbonyloxy group, etc.), amino Group (amino group, methylamino group, dimethylamino group, anilino group, N-methyl-anilino group, diphenylamino group, etc.), acylamino group (formylamino group, acetylamino group, pivaloylamino group, lauroylamino group, benzoylamino group) Etc.), alkyl and arylsulfonylamino groups (methylsulfonylamino group, butylsulfonylamino group,
- a 1 , A 2 and B represent a benzene ring, a pyrrole ring, a pyrazole ring, an imidazole ring, a 1,2,3-triazole ring or a 1,2,4-triazole ring.
- This is preferable because a retardation film having excellent characteristics variation effect and excellent durability can be obtained.
- T 1 and T 2 each independently represents a pyrrole ring, a pyrazole ring, an imidazole ring, a 1,2,3-triazole ring or a 1,2,4-triazole ring.
- a pyrazole ring, a triazole ring, or an imidazole ring is preferable because a resin composition that is particularly excellent in retardation fluctuation suppression effect against humidity fluctuation and that has excellent durability is obtained, and is a pyrazole ring. It is particularly preferred.
- the pyrazole ring, imidazole ring, 1,2,3-triazole ring or 1,2,4-triazole ring represented by T 1 and T 2 may be a tautomer. Specific structures of the pyrrole ring, pyrazole ring, imidazole ring, 1,2,3-triazole ring or 1,2,4-triazole ring are shown below.
- R 5 represents a hydrogen atom or a non-aromatic substituent.
- the non-aromatic substituent represented by R 5 include the same groups as the non-aromatic substituent among the substituents that A 1 in the general formula (4) may have.
- the substituent represented by R 5 is a substituent having an aromatic group, A 1 and T 1 or B and T 1 are easily twisted, and A 1 , B and T 1 form an interaction with cellulose acetate. Since it becomes impossible, it is difficult to suppress the fluctuation
- R 5 is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or an acyl group having 1 to 5 carbon atoms, and particularly preferably a hydrogen atom.
- T 1 and T 2 may have a substituent.
- substituents include the same groups as the substituents that A 1 and A 2 in the general formula (4) may have.
- L 1 , L 2 , L 3 and L 4 each independently represent a single bond or a divalent linking group and represent a 5-membered or 6-membered fragrance via 2 or less atoms.
- An aromatic hydrocarbon ring or an aromatic heterocycle is linked.
- “Through 2 or less atoms” represents the minimum number of atoms existing between the connected substituents among the atoms constituting the linking group.
- the divalent linking group having 2 or less linking atoms is not particularly limited, and includes an alkylene group, an alkenylene group, an alkynylene group, O, (C ⁇ O), NR, S, and (O ⁇ S ⁇ O). It is a divalent linking group selected from the group or a linking group in which two of them are combined.
- R represents a hydrogen atom or a substituent.
- substituent represented by R include an alkyl group (methyl group, ethyl group, n-propyl group, isopropyl group, tert-butyl group, n-octyl group, 2-ethylhexyl group, etc.), cycloalkyl group (cyclohexyl).
- the divalent linking group represented by L 1 , L 2 , L 3 and L 4 may have a substituent. No particular restriction on the the substituent, but may include the same groups as the substituent that may be possessed by A 1 and A 2 in example Formula (4).
- n represents an integer of 0 to 5.
- the plurality of A 2 , T 2 , L 3 and L 4 in the general formula (4) may be the same or different.
- n is preferably an integer of 1 to 3, more preferably an integer of 1 or 2.
- the compound having a structure represented by the general formula (4) is preferably a compound having a structure represented by the general formula (5).
- a 1 , A 2 , T 1 , T 2 , L 1 , L 2 , L 3 and L 4 are respectively A 1 , A 2 , T 1 , T 2 , L 1 in the general formula (4).
- L 2 , L 3 and L 4 , A 3 and T 3 represent the same groups as A 1 and T 1 in the general formula (4), respectively, and
- L 5 and L 6 represent the general formula ( 4) represents the same group as L 1.
- m represents an integer of 0 to 4.
- n is preferably an integer of 0 to 2, more preferably an integer of 0 or 1.
- the compound having a structure represented by the general formula (4) is preferably a triazole compound having a structure represented by the following general formula (6).
- a 1, B, L 1 and L 2 are .k representing the A 1, B, the same group as L 1 and L 2 in formula (4) represents an integer of 1 to 4 1 represents a 1,2,4-triazole ring.
- the triazole compound having a structure represented by the general formula (6) is preferably a triazole compound having a structure represented by the following general formula (7).
- Z represents the structure of the following general formula (8).
- Q represents an integer of 2 or 3.
- At least two Z are ortho-position or meta-position with respect to at least one Z substituted on the benzene ring. To join.
- R 10 represents a hydrogen atom, an alkyl group or an alkoxy group.
- P represents an integer of 1 to 5. * represents a bonding position with a benzene ring.
- T 1 represents a 1,2,4-triazole ring. Represents.
- the compound having the structure represented by the general formula (4), (5), (6) or (7) may form a hydrate, a solvate or a salt.
- the hydrate may contain an organic solvent
- the solvate may contain water. That is, “hydrate” and “solvate” include mixed solvates containing both water and organic solvents.
- Salts include acid addition salts formed with inorganic or organic acids. Examples of inorganic acids include, but are not limited to, hydrohalic acids (hydrochloric acid, hydrobromic acid, etc.), sulfuric acid, phosphoric acid and the like.
- organic acids examples include acetic acid, trifluoroacetic acid, propionic acid, butyric acid, oxalic acid, citric acid, benzoic acid, alkyl sulfonic acid (such as methane sulfonic acid), allyl sulfonic acid (benzene sulfonic acid, 4-toluene sulfone) Acid, 1,5-naphthalenedisulfonic acid, etc.) and the like.
- alkyl sulfonic acid such as methane sulfonic acid
- allyl sulfonic acid benzene sulfonic acid, 4-toluene sulfone
- Acid 1,5-naphthalenedisulfonic acid, etc.
- hydrochloride, acetate, propionate and butyrate are preferable.
- salts are those wherein the acidic moiety present in the parent compound is a metal ion (eg, an alkali metal salt, such as a sodium or potassium salt, an alkaline earth metal salt, such as a calcium or magnesium salt, an ammonium salt, an alkali metal ion, an alkaline earth metal And salts formed when substituted with organic bases (ethanolamine, diethanolamine, triethanolamine, morpholine, piperidine, etc.). Not. Of these, sodium salts and potassium salts are preferred.
- a metal ion eg, an alkali metal salt, such as a sodium or potassium salt, an alkaline earth metal salt, such as a calcium or magnesium salt, an ammonium salt, an alkali metal ion, an alkaline earth metal
- organic bases ethanolamine, diethanolamine, triethanolamine, morpholine, piperidine, etc.
- sodium salts and potassium salts are preferred.
- Examples of the solvent contained in the solvate include any common organic solvent. Specifically, alcohol (eg, methanol, ethanol, 2-propanol, 1-butanol, 1-methoxy-2-propanol, t-butanol), ester (eg, ethyl acetate), hydrocarbon (eg, toluene, hexane, Heptane), ether (eg, tetrahydrofuran), nitrile (eg, acetonitrile), ketone (acetone) and the like.
- Preferred are solvates of alcohols (eg, methanol, ethanol, 2-propanol, 1-butanol, 1-methoxy-2-propanol, t-butanol).
- These solvents may be reaction solvents used in the synthesis of the compound, may be used in crystallization purification after the synthesis, or may be a mixture thereof.
- two or more kinds of solvents may be included at the same time, or a form containing water and a solvent (for example, water and alcohol (for example, methanol, ethanol, t-butanol, etc.)) may be used.
- a solvent for example, water and alcohol (for example, methanol, ethanol, t-butanol, etc.)
- the molecular weight of the compound having the structure represented by the general formula (4), (5), (6) or (7) is not particularly limited. However, the smaller the compound, the better the compatibility with the resin. Since the effect of suppressing fluctuation of the optical value with respect to the change is high, it is preferably 150 to 2000, more preferably 200 to 1500, and more preferably 300 to 1000.
- the nitrogen-containing heterocyclic compound according to this embodiment is particularly preferably a compound having a structure represented by the following general formula (3).
- A represents a pyrazole ring
- Ar 1 and Ar 2 each represents an aromatic hydrocarbon ring or an aromatic heterocyclic ring, and may have a substituent.
- R 1 represents a hydrogen atom, an alkyl group, an acyl group;
- q represents an integer of 1 or 2
- n and m represent an integer of 1 to 3.
- the aromatic hydrocarbon ring or aromatic heterocyclic ring represented by Ar 1 and Ar 2 is preferably the 5-membered or 6-membered aromatic hydrocarbon ring or aromatic heterocyclic ring mentioned in the general formula (4), respectively.
- Examples of the substituent for Ar 1 and Ar 2 include the same substituents as those shown for the compound having the structure represented by the general formula (4).
- R 1 examples include a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom, etc.), alkyl group (methyl group, ethyl group, n-propyl group, isopropyl group, tert-butyl group, n-octyl group).
- halogen atom fluorine atom, chlorine atom, bromine atom, iodine atom, etc.
- alkyl group methyl group, ethyl group, n-propyl group, isopropyl group, tert-butyl group, n-octyl group.
- acyl group acetyl group, pivaloylbenzoyl group, etc.
- sulfonyl group eg, methylsulfonyl group, ethylsulfonyl group, etc.
- alkyloxycarbonyl group eg, methoxycarbonyl group
- aryloxycarbonyl Group for example, phenoxycarbonyl group and the like
- Q represents an integer of 1 or 2
- n and m represent integers of 1 to 3.
- the compound having the structure represented by the general formula (4) can be synthesized by a known method.
- any compound having a 1,2,4-triazole ring may be used, but a nitrile derivative or imino ether derivative and a hydrazide derivative are reacted.
- the method of making it preferable is.
- the solvent used in the reaction may be any solvent as long as it does not react with the raw material, but may be an ester type (for example, ethyl acetate, methyl acetate, etc.), an amide type (dimethylformamide, dimethylacetamide, etc.), an ether type (ethylene glycol) Dimethyl ether), alcohols (eg methanol, ethanol, propanol, isopropanol, n-butanol, 2-butanol, ethylene glycol, ethylene glycol monomethyl ether, etc.), aromatic hydrocarbons (eg toluene, xylene, etc.), water Can be done.
- the solvent to be used is preferably an alcohol solvent. These solvents may be used in combination.
- the amount of the solvent used is not particularly limited, but is preferably in the range of 0.5 to 30 times, more preferably 1.0 to 25 times the mass of the hydrazide derivative used. Particularly preferably, it is within the range of 3.0 to 20 times.
- a catalyst When reacting a nitrile derivative and a hydrazide derivative, it is not necessary to use a catalyst, but it is preferable to use a catalyst in order to accelerate the reaction.
- a catalyst to be used an acid or a base may be used.
- the acid include hydrochloric acid, sulfuric acid, nitric acid, acetic acid and the like, and hydrochloric acid is preferable.
- the acid may be added after diluted in water, or may be added by a method of blowing a gas into the system.
- Bases include inorganic bases (potassium carbonate, sodium carbonate, potassium bicarbonate, sodium bicarbonate, potassium hydroxide, sodium hydroxide, etc.) and organic bases (sodium methylate, sodium ethylate, potassium methylate, potassium ethylate, sodium (Butyrate, potassium butyrate, diisopropylethylamine, N, N'-dimethylaminopyridine, 1,4-diazabicyclo [2.2.2] octane, N-methylmorpholine, imidazole, N-methylimidazole, pyridine, etc.) May be used.
- the inorganic base is preferably potassium carbonate, and the organic base is preferably sodium ethylate, sodium ethylate, or sodium butyrate.
- the inorganic base may be added as a powder or may be added in a state dispersed in a solvent.
- the organic base may be added in a state dissolved in a solvent (for example, a 28% methanol solution of sodium methylate).
- the amount of the catalyst used is not particularly limited as long as the reaction proceeds, but it is preferably in the range of 1.0 to 5.0 moles relative to the formed triazole ring, and more preferably 1.05 to 3.0. Within the range of double moles is preferred.
- the target product can be obtained by heating in a solvent.
- the addition method of the raw material, solvent and catalyst used in the reaction is not particularly limited, and the catalyst may be added last, or the solvent may be added last. Also preferred is a method of dispersing or dissolving a nitrile derivative in a solvent, adding a catalyst, and then adding a hydrazide derivative.
- the solution temperature during the reaction may be any temperature as long as the reaction proceeds, but is preferably in the range of 0 to 150 ° C, more preferably in the range of 20 to 140 ° C. Moreover, you may react, removing the water to produce
- any method may be used for treating the reaction solution, but when a base is used as a catalyst, a method of neutralizing the reaction solution by adding an acid is preferable.
- the acid used for neutralization include hydrochloric acid, sulfuric acid, nitric acid and acetic acid, with acetic acid being particularly preferred.
- the amount of the acid used for neutralization is not particularly limited as long as the pH of the reaction solution is in the range of 4 to 9, but it is preferably 0.1 to 3 moles, particularly preferably 0. It is in the range of 2 to 1.5 times mole.
- the appropriate organic solvent mentioned here is a water-insoluble solvent such as ethyl acetate, toluene, dichloromethane, ether, or a mixed solvent of the water-insoluble solvent and tetrahydrofuran or an alcohol solvent, preferably ethyl acetate. It is.
- Exemplary Compound 1 can be synthesized by the following scheme.
- the precipitate collected by filtration was dissolved in 80 ml of methanol, 300 ml of pure water was added, and acetic acid was added dropwise until the pH of the solution reached 7.
- the precipitated crystals were collected by filtration, washed with pure water, and blown and dried at 50 ° C. to obtain 38.6 g of Exemplified Compound 1.
- the yield was 70% based on benzoylhydrazine.
- Exemplary compound 176 can be synthesized according to the following scheme.
- the 1 H-NMR spectrum of the obtained exemplary compound 176 is as follows. In order to avoid complication of chemical shift due to the presence of tautomers, the measurement was performed by adding a few drops of trifluoroacetic acid to the measurement solvent.
- the compound having the structure represented by the general formulas (3) to (5) according to the present embodiment can be appropriately adjusted and contained in the retardation film, but the addition amount is in the retardation film. 0.1 to 10% by mass, preferably 1 to 5% by mass, more preferably 2 to 5% by mass.
- the addition amount varies depending on the type of cellulose acetate and the type of the compound, but the optimum value can be determined by the addition amount at which the retardation film of the present embodiment exhibits a desired retardation value. If it is in this range, the fluctuation
- the compound having the structure represented by the general formulas (3) to (5) may be added as a powder to the resin forming the retardation film. You may add to resin which forms a film.
- the retardation film of the present embodiment preferably contains other additives, and examples thereof include a plasticizer, an antioxidant, an ultraviolet absorber, a light stabilizer, an antistatic agent, and a release agent.
- the compound used more effectively preferably contains a plasticizer, and among them, a sugar ester described below, or a polycondensed ester containing a repeating unit obtained by reacting a dicarboxylic acid and a diol is used. , Excellent compatibility with cellulose ester, control of moisture in / out of high humidity to reduce phase difference fluctuation, and control saponification liquid penetration into saponification solution To preferred.
- the sugar ester used in the retardation film of the present embodiment is a sugar ester having at least one pyranose ring or furanose ring of 1 to 12 and esterifying all or part of the OH groups of the structure. Preferably there is.
- the sugar ester according to this embodiment is preferably added for the purpose of preventing hydrolysis.
- the sugar ester according to this embodiment is a compound containing at least one of a furanose ring and a pyranose ring, and may be a monosaccharide or a polysaccharide having 2 to 12 sugar structures linked together.
- the sugar ester is preferably a compound in which at least one OH group of the sugar structure is esterified.
- the average ester substitution degree is preferably within the range of 4.0 to 8.0, and more preferably within the range of 5.0 to 7.5.
- sugar esters in the present embodiment include sugar esters represented by the following general formula (A).
- G represents a monosaccharide or disaccharide residue
- R 2 represents an aliphatic group or an aromatic group.
- m is the sum of the number of hydroxy groups directly attached to the monosaccharide or disaccharide residue
- n is directly attached to the monosaccharide or disaccharide residue — (O—C ( ⁇ O) -R 2 ) Total number of groups, 3 ⁇ m + n ⁇ 8, and n ⁇ 0.
- the sugar ester having the structure represented by the general formula (A) is a single kind of compound in which the number (m) of hydroxy groups and the number (n) of — (O—C ( ⁇ O) —R 2 ) groups are fixed It is known that it becomes a compound in which several components having different m and n in the formula are mixed. Therefore, the performance as a mixture in which the number (m) of hydroxy groups and the number (n) of — (O—C ( ⁇ O) —R 2 ) groups are changed is important, and the retardation film of the present embodiment In this case, sugar esters having an average ester substitution degree in the range of 5.0 to 7.5 are preferred.
- G represents a monosaccharide or disaccharide residue.
- monosaccharides include allose, altrose, glucose, mannose, gulose, idose, galactose, talose, ribose, arabinose, xylose, lyxose, and the like.
- disaccharide residue examples include trehalose, sucrose, maltose, cellobiose, gentiobiose, lactose, and isotrehalose.
- R 2 represents an aliphatic group or an aromatic group.
- the aliphatic group and the aromatic group may each independently have a substituent.
- m is the total number of hydroxy groups directly bonded to monosaccharide or disaccharide residues
- n is directly bonded to monosaccharide or disaccharide residues. This is the total number of — (O—C ( ⁇ O) —R 2 ) groups. Further, it is necessary that 3 ⁇ m + n ⁇ 8, and it is preferable that 4 ⁇ m + n ⁇ 8. Further, n ⁇ 0. When n is 2 or more, the — (O—C ( ⁇ O) —R 2 ) groups may be the same or different.
- the aliphatic group in the definition of R 2 may be linear, branched or cyclic, and preferably has 1 to 25 carbon atoms, more preferably 1 to 20 carbon atoms. Those of 2 to 15 are particularly preferred. Specific examples of the aliphatic group include, for example, methyl, ethyl, n-propyl, iso-propyl, cyclopropyl, n-butyl, iso-butyl, tert-butyl, amyl, iso-amyl, tert-amyl, n-hexyl.
- the aromatic group in the definition of R 2 may be an aromatic hydrocarbon group or an aromatic heterocyclic group, and more preferably an aromatic hydrocarbon group.
- the aromatic hydrocarbon group preferably has 6 to 24 carbon atoms, more preferably 6 to 12 carbon atoms. Specific examples of the aromatic hydrocarbon group include rings such as benzene, naphthalene, anthracene, biphenyl, and terphenyl. As the aromatic hydrocarbon group, a benzene ring, a naphthalene ring, and a biphenyl ring are particularly preferable.
- the aromatic heterocyclic group is preferably a ring containing at least one of an oxygen atom, a nitrogen atom or a sulfur atom.
- heterocyclic ring examples include, for example, furan, pyrrole, thiophene, imidazole, pyrazole, pyridine, pyrazine, pyridazine, triazole, triazine, indole, indazole, purine, thiazoline, thiadiazole, oxazoline, oxazole, oxadiazole, quinoline, isoquinoline.
- aromatic heterocyclic group a pyridine ring, a triazine ring, and a quinoline ring are particularly preferable.
- a sugar ester may contain two or more different substituents in one molecule, can contain an aromatic substituent and an aliphatic substituent in one molecule, and can contain two or more different aromatics.
- a group substituent can be contained in one molecule, and two or more different aliphatic substituents can be contained in one molecule.
- the addition amount of the sugar ester is preferably in the range of 0.1 to 20% by mass relative to the cellulose ester, and more preferably in the range of 1 to 15% by mass.
- Polycondensed ester As the polycondensation ester used in the retardation film of the present embodiment, it is preferable to use a polycondensation ester having a structure represented by the following general formula (9).
- the polycondensed ester is preferably contained in the range of 1 to 30% by mass and more preferably in the range of 5 to 20% by mass in the retardation film of the present embodiment because of its plastic effect.
- B 3 and B 4 each independently represents an aliphatic or aromatic monocarboxylic acid residue or a hydroxy group.
- G 2 represents an alkylene glycol residue having 2 to 12 carbon atoms, an aryl glycol residue having 6 to 12 carbon atoms, or an oxyalkylene glycol residue having 4 to 12 carbon atoms.
- A represents an alkylene dicarboxylic acid residue having 4 to 12 carbon atoms or an aryl dicarboxylic acid residue having 6 to 12 carbon atoms.
- n represents an integer of 1 or more.
- the polycondensed ester of this embodiment is a polycondensed ester containing a repeating unit obtained by reacting a dicarboxylic acid and a diol, A represents a carboxylic acid residue in the polycondensed ester, and G 2 represents an alcohol residue. .
- the dicarboxylic acid constituting the polycondensed ester is an aromatic dicarboxylic acid, an aliphatic dicarboxylic acid or an alicyclic dicarboxylic acid, preferably an aromatic dicarboxylic acid.
- the dicarboxylic acid may be one type or a mixture of two or more types. In particular, it is preferable to mix aromatic and aliphatic.
- the diol constituting the polycondensed ester is an aromatic diol, an aliphatic diol or an alicyclic diol, preferably an aliphatic diol, more preferably a diol having 1 to 4 carbon atoms.
- the diol may be one type or a mixture of two or more types.
- Both ends of the polycondensed ester molecule may or may not be sealed.
- alkylene dicarboxylic acid constituting A in the general formula (9) examples include 1,2-ethanedicarboxylic acid (succinic acid), 1,3-propanedicarboxylic acid (glutaric acid), 1,4-butanedicarboxylic acid ( Divalent groups derived from adipic acid), 1,5-pentanedicarboxylic acid (pimelic acid), 1,8-octanedicarboxylic acid (sebacic acid) and the like are included.
- alkenylene dicarboxylic acid constituting A include maleic acid and fumaric acid.
- aryl dicarboxylic acid constituting A examples include 1,2-benzenedicarboxylic acid (phthalic acid), 1,3-benzenedicarboxylic acid, 1,4-benzenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, and the like. It is done.
- A may be one type, or two or more types may be combined. Among these, A is preferably a combination of an alkylene dicarboxylic acid having 4 to 12 carbon atoms and an aryl dicarboxylic acid having 8 to 12 carbon atoms.
- G 2 in the general formula (9) is a divalent group derived from an alkylene glycol having 2 to 12 carbon atoms, a divalent group derived from an aryl glycol having 6 to 12 carbon atoms, or 4 carbon atoms. Represents a divalent group derived from ⁇ 12 oxyalkylene glycols.
- Examples of the divalent group derived from an alkylene glycol having 2 to 12 carbon atoms in G 2 include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1, 3-butanediol, 1,2-propanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol ( Neopentyl glycol), 2,2-diethyl-1,3-propanediol (3,3-dimethylolpentane), 2-n-butyl-2-ethyl-1,3-propanediol (3,3-dimethylol) Heptane), 3-methyl-1,5-pentanediol, 1,6-hexanediol, 2,2,4-trimethyl-1,3-pentanediol
- divalent groups derived from aryl glycols having 6 to 12 carbon atoms in G 2 include 1,2-dihydroxybenzene (catechol), 1,3-dihydroxybenzene (resorcinol), 1,4-dihydroxybenzene Divalent groups derived from (hydroquinone) and the like are included.
- divalent group derived from oxyalkylene glycol having 4 to 12 carbon atoms in G are 2 derived from diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol and the like. Valent groups are included.
- G 2 is preferably a divalent group derived from an alkylene glycol having 2 to 12 carbon atoms, more preferably 2 to 5, and most preferably 2 to 4.
- B 3 and B 4 in the general formula (9) are each a monovalent group or a hydroxy group derived from an aromatic ring-containing monocarboxylic acid or an aliphatic monocarboxylic acid.
- An aromatic ring-containing monocarboxylic acid in a monovalent group derived from an aromatic ring-containing monocarboxylic acid is a carboxylic acid containing an aromatic ring in the molecule, and not only those in which the aromatic ring is directly bonded to a carboxy group, but also aromatic Also included are those in which a ring is bonded to a carboxy group via an alkylene group or the like.
- Examples of monovalent groups derived from aromatic ring-containing monocarboxylic acids include benzoic acid, para-tert-butyl benzoic acid, orthotoluic acid, metatoluic acid, p-toluic acid, dimethyl benzoic acid, ethyl benzoic acid, normal propyl benzoic acid, Monovalent groups derived from aminobenzoic acid, acetoxybenzoic acid, phenylacetic acid, 3-phenylpropionic acid and the like are included. Of these, benzoic acid and p-toluic acid are preferable.
- Examples of monovalent groups derived from aliphatic monocarboxylic acids include monovalent groups derived from acetic acid, propionic acid, butanoic acid, caprylic acid, caproic acid, decanoic acid, dodecanoic acid, stearic acid, oleic acid and the like. A group is included. Among these, a monovalent group derived from an alkyl monocarboxylic acid having 1 to 3 carbon atoms in the alkyl portion is preferable, and an acetyl group (a monovalent group derived from acetic acid) is more preferable.
- the weight average molecular weight of the polycondensed ester according to the present invention is preferably in the range of 500 to 3000, and more preferably in the range of 600 to 2000.
- the weight average molecular weight can be measured by gel permeation chromatography (GPC).
- Polycondensed ester P4 251 g of 1,2-propylene glycol, 354 g of terephthalic acid, 610 g of benzoic acid, and 0.191 g of tetraisopropyl titanate as an esterification catalyst were charged into a 2 L four-necked flask equipped with a thermometer, a stirrer, and a quick cooling tube. The temperature is gradually raised with stirring until it reaches 230 ° C. in an air stream. The dehydration condensation reaction was carried out while observing the degree of polymerization. After completion of the reaction, unreacted 1,2-propylene glycol was distilled off at 200 ° C. under reduced pressure to obtain a polycondensed ester P4. The acid value was 0.10 and the number average molecular weight was 400.
- Polycondensed ester P5 251 g of 1,2-propylene glycol, 354 g of terephthalic acid, 680 g of p-troyl acid, and 0.191 g of tetraisopropyl titanate as an esterification catalyst are charged into a 2 L four-necked flask equipped with a thermometer, stirrer, and slow cooling tube. The temperature is gradually raised with stirring until it reaches 230 ° C. in a nitrogen stream. The dehydration condensation reaction was carried out while observing the degree of polymerization. After completion of the reaction, unreacted 1,2-propylene glycol was distilled off at 200 ° C. under reduced pressure to obtain the following polycondensed ester P5. The acid value was 0.30 and the number average molecular weight was 400.
- Polycondensed ester P6 180 g of 1,2-propylene glycol, 292 g of adipic acid, and 0.191 g of tetraisopropyl titanate as an esterification catalyst were charged into a 2 L four-necked flask equipped with a thermometer, a stirrer, and a slow cooling tube, in a nitrogen stream. The temperature is gradually raised while stirring until 200 ° C is reached. The dehydration condensation reaction was carried out while observing the degree of polymerization. After completion of the reaction, unreacted 1,2-propylene glycol was distilled off under reduced pressure at 200 ° C. to obtain a polycondensed ester P6. The acid value was 0.10 and the number average molecular weight was 400.
- Polycondensed ester P7 180 g of 1,2-propylene glycol, 244 g of phthalic anhydride, 103 g of adipic acid, and 0.191 g of tetraisopropyl titanate as an esterification catalyst were charged into a 2 L four-necked flask equipped with a thermometer, stirrer, and quick cooling tube. The temperature is gradually raised with stirring until it reaches 200 ° C. in a nitrogen stream. The dehydration condensation reaction was carried out while observing the degree of polymerization. After completion of the reaction, unreacted 1,2-propylene glycol was distilled off under reduced pressure at 200 ° C. to obtain a polycondensed ester P7. The acid value was 0.10 and the number average molecular weight was 320.
- plasticizers examples include polyhydric alcohol esters, polyhydric carboxylic acid esters (including phthalic acid esters), glycolate compounds, fatty acid esters, and phosphoric acid esters. These may be used alone or in combination of two or more.
- the polyhydric alcohol ester is an ester (alcohol ester) of a dihydric or higher aliphatic polyhydric alcohol and a monocarboxylic acid, preferably a divalent to 20-valent aliphatic polyhydric alcohol ester.
- the polyhydric alcohol ester preferably has an aromatic ring or a cycloalkyl ring in the molecule.
- Preferred examples of the aliphatic polyhydric alcohol include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, and 1,2-butane.
- Diol, 1,3-butanediol, 1,4-butanediol, dibutylene glycol, 1,2,4-butanetriol, 1,5-pentanediol, 1,6-hexanediol, hexanetriol, trimethylolpropane, Pentaerythritol, trimethylolethane, xylitol and the like are included.
- triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, sorbitol, trimethylolpropane, xylitol and the like are preferable.
- the monocarboxylic acid is not particularly limited, and may be an aliphatic monocarboxylic acid, an alicyclic monocarboxylic acid, an aromatic monocarboxylic acid, or the like. In order to increase the moisture permeability of the film and make it less likely to volatilize, alicyclic monocarboxylic acids or aromatic monocarboxylic acids are preferred. One kind of monocarboxylic acid may be used, or a mixture of two or more kinds may be used. Further, all of the OH groups contained in the aliphatic polyhydric alcohol may be esterified, or a part of the OH groups may be left as they are.
- the aliphatic monocarboxylic acid is preferably a fatty acid having a straight chain or a side chain having 1 to 32 carbon atoms.
- the number of carbon atoms of the aliphatic monocarboxylic acid is more preferably 1-20, and still more preferably 1-10.
- aliphatic monocarboxylic acids include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, 2-ethyl-hexanoic acid, undecylic acid, lauric acid, tridecylic acid, Saturated fatty acids such as myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, heptacosanoic acid, montanic acid, melicic acid, and laccelic acid; undecylenic acid, olein Examples include unsaturated fatty acids such as acid, sorbic acid, linoleic acid, linolenic acid, and arachidonic acid. Of these, acetic acid or a mixture of acetic
- Examples of the alicyclic monocarboxylic acid include cyclopentane carboxylic acid, cyclohexane carboxylic acid, cyclooctane carboxylic acid and the like.
- aromatic monocarboxylic acids examples include benzoic acid; benzoic acid having 1 to 3 alkyl groups or alkoxy groups (for example, methoxy group or ethoxy group) introduced into the benzene ring (for example, toluic acid); Aromatic monocarboxylic acids having two or more (for example, biphenyl carboxylic acid, naphthalene carboxylic acid, tetralin carboxylic acid, etc.) are included, and benzoic acid is preferred.
- polyhydric alcohol ester examples include compounds described in paragraphs [0058] to [0061] of JP-A-2006-113239.
- the polyvalent carboxylic acid ester is an ester of a divalent or higher, preferably 2 to 20 valent polycarboxylic acid and an alcohol compound.
- the polyvalent carboxylic acid is preferably a divalent to 20-valent aliphatic polyvalent carboxylic acid, a 3- to 20-valent aromatic polyvalent carboxylic acid, or a 3- to 20-valent alicyclic polyvalent carboxylic acid.
- polyvalent carboxylic acids include trivalent or higher aromatic polyvalent carboxylic acids such as trimellitic acid, trimesic acid, pyromellitic acid or derivatives thereof, succinic acid, adipic acid, azelaic acid, sebacic acid, oxalic acid, Contains aliphatic polycarboxylic acids such as fumaric acid, maleic acid and tetrahydrophthalic acid, oxypolycarboxylic acids such as tartaric acid, tartronic acid, malic acid and citric acid, etc. to suppress volatilization from the film Is preferably an oxypolycarboxylic acid.
- trivalent or higher aromatic polyvalent carboxylic acids such as trimellitic acid, trimesic acid, pyromellitic acid or derivatives thereof, succinic acid, adipic acid, azelaic acid, sebacic acid, oxalic acid
- Contains aliphatic polycarboxylic acids such as fumaric acid, maleic acid and
- the alcohol compound examples include an aliphatic saturated alcohol compound having a linear or side chain, an aliphatic unsaturated alcohol compound having a linear or side chain, an alicyclic alcohol compound, or an aromatic alcohol compound.
- the carbon number of the aliphatic saturated alcohol compound or the aliphatic unsaturated alcohol compound is preferably 1 to 32, more preferably 1 to 20, and still more preferably 1 to 10.
- Examples of the alicyclic alcohol compound include cyclopentanol, cyclohexanol and the like.
- the aromatic alcohol compound examples include benzyl alcohol and cinnamyl alcohol.
- the molecular weight of the polycarboxylic acid ester is not particularly limited, but is preferably in the range of 300 to 1000, more preferably in the range of 350 to 750.
- the molecular weight of the polycarboxylic acid ester plasticizer is preferably large from the viewpoint of suppressing bleed out, and is preferably small from the viewpoint of moisture permeability and compatibility with cellulose acetate.
- polyvalent carboxylic acid esters examples include triethyl citrate, tributyl citrate, acetyl triethyl citrate (ATEC), acetyl tributyl citrate (ATBC), benzoyl tributyl citrate, acetyl triphenyl citrate, acetyl tribenzyl citrate, Examples include dibutyl tartrate, diacetyl dibutyl tartrate, tributyl trimellitic acid, and tetrabutyl pyromellitic acid.
- the polyvalent carboxylic acid ester may be a phthalic acid ester.
- the phthalic acid ester include diethyl phthalate, dimethoxyethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, dioctyl phthalate, dicyclohexyl phthalate, dicyclohexyl terephthalate and the like.
- glycolate compounds include alkylphthalyl alkyl glycolates.
- alkyl phthalyl alkyl glycolates include methyl phthalyl methyl glycolate, ethyl phthalyl ethyl glycolate, propyl phthalyl propyl glycolate, butyl phthalyl butyl glycolate, octyl phthalyl octyl glycolate, methyl phthalyl ethyl Glycolate, ethyl phthalyl methyl glycolate, ethyl phthalyl propyl glycolate, methyl phthalyl butyl glycolate, ethyl phthalyl butyl glycolate, butyl phthalyl methyl glycolate, butyl phthalyl ethyl glycolate, propyl phthalyl butyl glycol Butyl phthalyl propyl glycolate, methyl phthalyl octyl glycolate, ethyl phthalyl
- Esters include fatty acid esters, citrate esters and phosphate esters.
- fatty acid esters include butyl oleate, methylacetyl ricinoleate, and dibutyl sebacate.
- citrate ester include acetyltrimethyl citrate, acetyltriethyl citrate, and acetyltributyl citrate.
- phosphate ester include triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, biphenyl diphenyl phosphate, trioctyl phosphate, tributyl phosphate, and the like, and preferably triphenyl phosphate.
- polyester glycolate compound, and phosphate ester are preferable, and polyester is particularly preferable.
- the content of the plasticizer is preferably in the range of 1 to 20% by mass, more preferably in the range of 1.5 to 15% by mass with respect to the cellulose ester.
- the content of the plasticizer is within the above range, an effect of imparting plasticity can be exhibited, and the plasticizer is also excellent in resistance to bleeding.
- Antioxidants are also called deterioration inhibitors. When a liquid crystal image display device or the like is placed in a high humidity and high temperature environment, the retardation film may be deteriorated.
- the antioxidant has a role of delaying or preventing the retardation film from being decomposed by, for example, the residual solvent amount of halogen in the retardation film or phosphoric acid of the phosphoric acid plasticizer. Thereby, it is preferable to contain antioxidant in retardation film.
- a hindered phenol compound is preferably used.
- 2,6-di-t-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3 -(3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate] is preferred.
- hydrazine-based metal deactivators such as N, N′-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine and tris (2,4-di-t A phosphorus processing stabilizer such as -butylphenyl) phosphite may be used in combination.
- the amount of these compounds added is preferably in the range of 1 ppm to 1.0% by mass ratio with respect to the cellulose ester, and more preferably in the range of 10 to 1000 ppm.
- the retardation film of this embodiment can contain an ultraviolet absorber for the purpose of imparting an ultraviolet absorbing function.
- the ultraviolet absorber is not particularly limited, and examples thereof include an ultraviolet absorber such as benzotriazole, 2-hydroxybenzophenone, or salicylic acid phenyl ester.
- an ultraviolet absorber such as benzotriazole, 2-hydroxybenzophenone, or salicylic acid phenyl ester.
- 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- [2-hydroxy-3,5-bis ( ⁇ , ⁇ -dimethylbenzyl) phenyl] -2H-benzotriazole, 2- (3 Triazoles such as 5-di-t-butyl-2-hydroxyphenyl) benzotriazole, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone Benzophenones such as
- UV absorbers with a molecular weight of 400 or more are difficult to sublimate or volatilize at a high boiling point, and are difficult to disperse even when the film is dried at high temperature. It is preferable from the viewpoint of improving weather resistance.
- Examples of the ultraviolet absorber having a molecular weight of 400 or more include 2- [2-hydroxy-3,5-bis ( ⁇ , ⁇ -dimethylbenzyl) phenyl] -2-benzotriazole, 2,2-methylenebis [4- (1 , 1,3,3-tetrabutyl) -6- (2H-benzotriazol-2-yl) phenol], bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis Hindered amines such as (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate and further 2- (3,5-di-t-butyl-4-hydroxybenzyl) -2-n-butylmalon Acid bis (1,2,2,6,6-pentamethyl-4-piperidyl), 1- [2- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy Cis] ethyl] -4- [3- (3,5-di-t-but
- 2- [2-hydroxy-3,5-bis ( ⁇ , ⁇ -dimethylbenzyl) phenyl] -2-benzotriazole and 2,2-methylenebis [4- (1,1,3,3- Tetrabutyl) -6- (2H-benzotriazol-2-yl) phenol] is particularly preferred.
- UV absorbers for example, Tinuvin 109, Tinuvin 171, Tinuvin 234, Tinuvin 326, Tinuvin 327, Tinuvin 328, Tinuvin 928, etc. manufactured by BASF Japan, or 2,2 ′ -Methylenebis [6- (2H-benzotriazol-2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol] (molecular weight 659; an example of a commercial product is LA31 manufactured by ADEKA Corporation) Can be preferably used.
- the above ultraviolet absorbers can be used alone or in combination of two or more.
- the amount of the UV absorber used is not uniform depending on the type of UV absorber, the operating conditions, etc., but is generally in the range of 0.05 to 10% by weight, preferably 0.1 to 5% by weight, based on cellulose acetate. Is added.
- the method of adding the UV absorber may be added to the dope after dissolving the UV absorber in an alcohol such as methanol, ethanol, butanol, an organic solvent such as methylene chloride, methyl acetate, acetone, dioxolane, or a mixed solvent thereof. Or you may add directly in dope composition.
- an alcohol such as methanol, ethanol, butanol
- an organic solvent such as methylene chloride, methyl acetate, acetone, dioxolane, or a mixed solvent thereof.
- inorganic powders that do not dissolve in organic solvents use a dissolver or sand mill in the organic solvent and cellulose acetate to disperse them before adding them to the dope.
- the retardation film of this embodiment may further contain fine particles (matting agent) as necessary in order to improve the slipperiness of the surface.
- the fine particles may be inorganic fine particles or organic fine particles.
- inorganic fine particles include silicon dioxide (silica), titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, silica
- magnesium acid and calcium phosphate examples include magnesium acid and calcium phosphate.
- silicon dioxide and zirconium oxide are preferable, and silicon dioxide is more preferable in order to reduce an increase in haze of the obtained film.
- Examples of the fine particles of silicon dioxide include Aerosil R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, TT600, NAX50 (manufactured by Nippon Aerosil Co., Ltd.), Seahoster KE-P10, KE-P30, KE -P50, KE-P100 (manufactured by Nippon Shokubai Co., Ltd.) and the like.
- Aerosil R972V, NAX50, Seahoster KE-P30 and the like are particularly preferable because they reduce the coefficient of friction while keeping the turbidity of the resulting film low.
- the primary particle diameter of the fine particles is preferably in the range of 5 to 50 nm, more preferably in the range of 7 to 20 nm.
- a larger primary particle size has a larger effect of increasing the slipperiness of the resulting film, but transparency tends to be lowered. Therefore, the fine particles may be contained as secondary aggregates having a particle diameter in the range of 0.05 to 0.3 ⁇ m.
- the size of the primary particles or the secondary aggregates of the fine particles is observed with a transmission electron microscope at a magnification of 500,000 to 2,000,000 times, and the primary particles or secondary aggregates are observed, and 100 particles of primary particles or secondary aggregates are observed. It can obtain
- the content of fine particles is preferably in the range of 0.05 to 1.0% by mass, more preferably in the range of 0.1 to 0.8% by mass with respect to the cellulose ester.
- the retardation film of the present embodiment can be produced, for example, by a solution casting method.
- the retardation film of this embodiment In the production of the retardation film of this embodiment, at least cellulose acetate and a retardation increasing agent are dissolved in a solvent to prepare a dope, and the dope is filtered.
- the prepared dope is cast on a belt-shaped or drum-shaped metal support. It is performed by a step of forming a web, a step of peeling the formed web from a metal support to form a film, a step of stretching and drying the film, and a step of winding the dried film into a roll after cooling.
- the retardation film of the present embodiment preferably contains cellulose ester in the range of 60 to 95% by mass in the solid content.
- the cellulose ester, and in some cases, the retardation increasing agent, sugar ester, polycondensation ester, and other compounds in the dissolution vessel are stirred in an organic solvent mainly composed of a good solvent for the cellulose ester. It is a step of forming a dope which is a main solution by mixing a retardation increasing agent, a sugar ester, a polycondensation ester, and other compound solutions with the cellulose ester solution.
- an organic solvent useful for forming the dope can be used without limitation as long as it dissolves a cellulose ester, a retardation increasing agent and other compounds at the same time. Can do.
- methylene chloride as a chlorinated organic solvent, methyl acetate, ethyl acetate, amyl acetate, acetone, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, cyclohexanone, ethyl formate, 2, 2,2-trifluoroethanol, 2,2,3,3-hexafluoro-1-propanol, 1,3-difluoro-2-propanol, 1,1,1,3,3,3-hexafluoro-2- Mention may be made of methyl-2-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 2,2,3,3,3-pentafluoro-1-propanol, nitroethane and the like.
- methylene chloride, methyl acetate, ethyl acetate, and acetone can be preferably used as the main solvent, and methylene chloride or e
- the dope preferably contains a linear or branched aliphatic alcohol having 1 to 4 carbon atoms in the range of 1 to 40% by mass.
- a linear or branched aliphatic alcohol having 1 to 4 carbon atoms in the range of 1 to 40% by mass.
- the proportion of alcohol in the dope increases, the web gels and peeling from the metal support becomes easy.
- the proportion of alcohol is small, it also has a role of promoting dissolution of cellulose ester and other compounds in a non-chlorine organic solvent system.
- a method of producing using a dope having an alcohol concentration in the range of 0.5 to 15.0% by mass is applied in order to improve the flatness of the obtained retardation film. can do.
- a dope composition in which cellulose ester and other compounds are dissolved in a total amount of 15 to 45% by mass in a solvent containing methylene chloride and a linear or branched aliphatic alcohol having 1 to 4 carbon atoms.
- a solvent containing methylene chloride and a linear or branched aliphatic alcohol having 1 to 4 carbon atoms Preferably there is.
- linear or branched aliphatic alcohol having 1 to 4 carbon atoms examples include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, and tert-butanol. Methanol and ethanol are preferred because of the stability and boiling point of these dopes being relatively low and good drying properties.
- Cellulose ester, retardation increasing agent, sugar ester, polycondensation ester or other compounds are dissolved at normal pressure, at a temperature lower than the boiling point of the main solvent, at a pressure higher than the boiling point of the main solvent, A method for carrying out by the cooling dissolution method described in JP-A-9-95544, JP-A-9-95557, or JP-A-9-95538, a method for carrying out at a high pressure described in JP-A-11-21379, etc.
- a method of pressurizing at a pressure equal to or higher than the boiling point of the main solvent is particularly preferable.
- the concentration of the cellulose ester in the dope is preferably in the range of 10 to 40% by mass.
- the compound is added to the dope during or after dissolution to dissolve and disperse, then filtered through a filter medium, defoamed, and sent to the next step with a liquid feed pump.
- a filter medium having a leaf disk filter for example, with a filter medium having a 90% collection particle diameter of 10 to 100 times the average particle diameter of the fine particles.
- the filter medium used for filtration has a small absolute filtration accuracy.
- the absolute filtration accuracy is too small, the filter medium is likely to be clogged. As a result, the filter medium must be frequently exchanged, and there is a problem that productivity is lowered.
- the filter medium used for the cellulose ester dope preferably has an absolute filtration accuracy of 0.008 mm or less, more preferably in the range of 0.001 to 0.008 mm, and in the range of 0.003 to 0.006 mm.
- the filter medium is more preferable.
- filter medium there are no particular restrictions on the material of the filter medium, and ordinary filter media can be used. However, filter fibers made of plastic fibers such as polypropylene and Teflon (registered trademark) and metal filter media such as stainless steel fibers may cause the fibers to fall off. Less preferred.
- the dope flow rate during filtration is preferably 10 to 80 kg / (h ⁇ m 2 ), more preferably 20 to 60 kg / (h ⁇ m 2 ).
- the flow rate of the dope at the time of filtration is 10 kg / (h ⁇ m 2 ) or more, it becomes efficient productivity, and if the flow rate of the dope at the time of filtration is within 80 kg / (h ⁇ m 2 ). It is preferable that the pressure applied to the filter medium is appropriate and the filter medium is not damaged.
- the filtration pressure is preferably 3500 kPa or less, more preferably 3000 kPa or less, and even more preferably 2500 kPa or less.
- the filtration pressure can be controlled by appropriately selecting the filtration flow rate and the filtration area.
- a matting agent dispersion or an ultraviolet absorbent additive is added to the dope after filtration.
- the main dope may contain about 10 to 50% by weight of recycled material.
- Recycled material is, for example, a product obtained by finely pulverizing a cellulose ester-based film, which is generated when a cellulose ester-based film is produced. Cellulose ester film raw material is used.
- a pellet obtained by pelletizing cellulose ester and other compounds in advance can be preferably used as a raw material for the resin used for preparing the dope.
- the dope is fed to a pressure die through a liquid feed pump (for example, a pressurized metering gear pump) and transferred to an endless metal support (for example, a stainless belt, a rotating metal drum, etc.).
- a liquid feed pump for example, a pressurized metering gear pump
- an endless metal support for example, a stainless belt, a rotating metal drum, etc.
- the metal support in the casting process is preferably a mirror finished surface.
- a stainless steel belt or a drum whose surface is plated with a casting is preferably used.
- the cast width can be in the range of 1 to 4 m, preferably in the range of 1.5 to 3 m, more preferably in the range of 2 to 2.8 m.
- the surface temperature of the metal support in the casting step is set in the range of ⁇ 50 ° C. to the temperature at which the solvent boils and does not foam, more preferably in the range of ⁇ 30 to 0 ° C.
- a higher temperature is preferable because the web can be dried at a higher speed. However, if the temperature is too high, the web may foam or the flatness may deteriorate.
- a preferable temperature of the metal support is appropriately determined at 0 to 100 ° C., and more preferably within a range of 5 to 30 ° C. Alternatively, it is also a preferable method that the web is gelled by cooling and peeled from the drum in a state containing a large amount of residual solvent.
- the method for controlling the temperature of the metal support is not particularly limited, but there are a method of blowing hot air or cold air, and a method of contacting hot water with the back side of the metal support. It is preferable to use warm water because heat transfer is performed efficiently, so that the time until the temperature of the metal support becomes constant is short.
- warm air considering the temperature drop of the web due to the latent heat of vaporization of the solvent, while using warm air above the boiling point of the solvent, there may be cases where wind at a temperature higher than the target temperature is used while preventing foaming. .
- the pressure die includes a coat hanger die and a T die, and any of them is preferably used.
- the surface of the metal support is a mirror surface. In order to increase the production speed, two or more pressure dies may be provided on the metal support, and the dope amount may be divided and laminated.
- the solvent evaporation step is a step of heating a web (a dope film formed by casting a dope on a casting support) on the casting support to evaporate the solvent.
- the web on the metal support after casting is preferably dried on the metal support in an atmosphere of 40 to 100 ° C. In order to maintain the atmosphere at 40 to 100 ° C., it is preferable to apply hot air at this temperature to the upper surface of the web or heat by means such as infrared rays.
- a peeling process is a process of peeling the web which the solvent evaporated on the metal support body in a peeling position. The peeled web is sent to the next process as a film.
- the temperature at the peeling position on the metal support is preferably in the range of 10 to 40 ° C, more preferably in the range of 11 to 30 ° C.
- the residual solvent amount at the time of peeling of the web on the metal support is preferably peeled in the range of 50 to 120% by mass depending on the strength of drying conditions and the length of the metal support. If the web is peeled off when the amount of residual solvent is larger, if the web is too soft, the flatness at the time of peeling will be lost, and slippage and vertical stripes are likely to occur due to the peeling tension. The amount of residual solvent at the time of peeling is determined.
- the residual solvent amount of the web is defined by the following formula (10).
- Residual solvent amount (%) (mass before web heat treatment ⁇ mass after web heat treatment) / (mass after web heat treatment) ⁇ 100
- the heat treatment for measuring the residual solvent amount represents performing heat treatment at 115 ° C. for 1 hour.
- the peeling tension when peeling the metal support and the film (web) is usually in the range of 196 to 245 N / m. However, if wrinkles easily occur when peeling, peel with a tension of 190 N / m or less. Is preferred.
- the temperature at the peeling position on the metal support is preferably in the range of ⁇ 50 to 40 ° C., more preferably in the range of 10 to 40 ° C., and in the range of 15 to 30 ° C. Most preferably.
- a drying process is a process of drying the web obtained by peeling from a metal support body.
- a drying process can also be performed by dividing into a preliminary drying process and a main drying process.
- the web may be dried while being transported by a large number of rollers arranged above and below, or may be dried while being transported by fixing both ends of the web with clips as in a tenter dryer.
- the means for drying the web is not particularly limited, and can be generally performed with hot air, infrared rays, a heating roller, microwave, or the like, but it is preferably performed with hot air in terms of simplicity.
- the drying temperature in the web drying step is preferably a glass transition temperature of the film of ⁇ 5 ° C. or lower, and it is effective to perform a heat treatment at a temperature of 100 ° C. or higher for 10 minutes to 60 minutes. Drying is performed at a drying temperature in the range of 100 to 200 ° C, more preferably in the range of 110 to 160 ° C.
- the retardation film of this embodiment can be subjected to stretching treatment to control the orientation of molecules in the film, and the target in-plane direction retardation value Ro and thickness direction retardation value Rth can be obtained. it can.
- the retardation film of the present embodiment is preferably stretched in the casting direction (hereinafter sometimes referred to as “MD direction”) and / or in the width direction (hereinafter sometimes referred to as “TD direction”).
- the retardation film is preferably produced by stretching in the width direction by at least a tenter stretching apparatus.
- the stretching operation may be performed in multiple stages. Moreover, when performing biaxial stretching, simultaneous biaxial stretching may be performed and you may implement in steps.
- “stepwise” means that, for example, stretching in different stretching directions can be sequentially performed, stretching in the same direction can be divided into multiple stages, and stretching in different directions can be added to any one of the stages. Is possible.
- simultaneous biaxial stretching includes stretching in one direction and contracting the other while relaxing the tension.
- the residual solvent amount at the start of stretching is preferably in the range of 2 to 10% by mass.
- the amount of the residual solvent is 2% by mass or more, the film thickness deviation is small and is preferable from the viewpoint of flatness, and if it is within 10% by mass, the surface unevenness is reduced and the flatness is improved.
- the retardation film of the present embodiment has a film transition temperature in the MD direction and / or TD direction, preferably in the TD direction so that the film thickness after stretching is in a desired range, and when the glass transition temperature of the film is Tg (Tg + 15) It is preferable to stretch in a temperature range of ⁇ (Tg + 50) ° C. If the stretching is performed within the above temperature range, the retardation can be easily adjusted, and the stretching stress can be reduced, so that the haze is lowered. Moreover, the retardation film which suppressed generation
- the stretching temperature is preferably in the range of (Tg + 20) to (Tg + 40) ° C.
- the glass transition temperature Tg referred to here is a midpoint glass transition temperature (Tmg) determined according to JIS K7121 (1987) using a commercially available differential scanning calorimeter and measuring at a heating rate of 20 ° C./min. It is.
- Tmg midpoint glass transition temperature
- a specific method for measuring the glass transition temperature Tg of the retardation film is measured using a differential scanning calorimeter DSC220 manufactured by Seiko Instruments Inc. according to JIS K7121 (1987).
- the retardation film of this embodiment preferably stretches the web at least 1.1 times in the TD direction.
- the range of stretching is preferably 1.1 to 1.5 times the original width, and more preferably 1.2 to 1.4 times. If it is in the said range, the movement of the molecule
- peeling is preferably performed at a peeling tension of 130 N / m or more, particularly preferably 150 to 170 N / m. Since the web after peeling is in a high residual solvent state, stretching in the MD direction can be performed by maintaining the same tension as the peeling tension. As the web dries and the residual solvent amount decreases, the stretch ratio in the MD direction decreases.
- the draw ratio in the MD direction can be calculated from the rotation speed of the belt support and the tenter operation speed.
- the entire drying process or a part of the process as shown in Japanese Patent Application Laid-Open No. 62-46625 is performed while holding the width at both ends of the web with clips or pins in the width direction.
- a method (called a tenter method) is used.
- a tenter method using a clip and a pin tenter method using a pin are preferably used.
- stretching in the TD direction stretching in the width direction of the film at a stretching speed of 250 to 500% / min is preferable from the viewpoint of improving the flatness of the film.
- the stretching speed is 250% / min or more, the planarity is improved and the film can be processed at a high speed, which is preferable from the viewpoint of production aptitude, and if it is within 500% / min, the film is broken. It can be processed without any problem.
- a preferable stretching speed is in the range of 300 to 400% / min.
- the stretching speed is defined by the following formula (11).
- Stretching speed (% / min) [(d1 / d2) ⁇ 1] ⁇ 100 (%) / t (Where d1 is the width dimension in the stretching direction of the cellulose ester film after stretching, d2 is the width dimension in the stretching direction of the cellulose ester film before stretching, and t is the time (min) required for stretching. is there.)
- the retardation film of this embodiment contains a retardation increasing agent, and inevitably has retardation by stretching.
- the in-plane retardation value Ro and the thickness retardation value Rth are measured using an automatic birefringence meter Axoscan (Axo Scan Mueller Matrix Polarimeter: manufactured by Axometrics) at a temperature of 23 ° C. and a relative humidity of 55% RH.
- the refractive indexes n x , n y , and nz obtained by performing the three-dimensional refractive index measurement at the measurement wavelength of 590 nm can be calculated.
- the retardation film of the present embodiment is represented by the following formulas (12) and (13), the retardation value Ro in the in-plane direction of the retardation film is in the range of 45 to 60 nm, and the retardation in the thickness direction.
- the value Rth is preferably in the range of 110 to 140 nm from the viewpoint of improving visibility such as viewing angle and contrast when applied to a vertical alignment type liquid crystal display device.
- the retardation film can be adjusted within the range of the retardation value by stretching while adjusting the stretching ratio at least in the TD direction.
- ⁇ Knurling> After a predetermined heat treatment or cooling treatment, it is preferable to provide a slitter before winding to cut off the end portion in order to obtain a good winding shape. Furthermore, it is preferable to knurling both ends of the width.
- the knurling process can be formed by pressing a heated embossing roller. Fine embossing is formed on the embossing roller, and by pressing the embossing roller, unevenness can be formed on the film and the end can be made bulky.
- the height of the knurling at both widthwise ends of the retardation film of this embodiment is preferably 4 to 20 ⁇ m and the width is 5 to 20 mm.
- the knurling process is preferably provided after the drying process and before the winding in the film manufacturing process.
- ⁇ Winding process> This is a step of winding up as a film after the amount of residual solvent in the web is 2% by mass or less. By setting the residual solvent amount to 0.4% by mass or less, a film having good dimensional stability can be obtained.
- a generally used one may be used, and there are a constant torque method, a constant tension method, a taper tension method, a program tension control method with a constant internal stress, etc., and these may be used properly.
- the retardation film of the present embodiment preferably has a haze of less than 1%, and more preferably less than 0.5%. By setting the haze to less than 1%, there is an advantage that the transparency of the film becomes higher and it becomes easier to use as a film for optical applications.
- the equilibrium moisture content at a temperature of 25 ° C. and a relative humidity of 60% RH is preferably 4% or less, and more preferably 3% or less.
- the equilibrium moisture content is preferable that it is easy to cope with changes in humidity and the optical characteristics and dimensions are more difficult to change.
- the retardation film of the present embodiment is preferably long, specifically about 100 to 10,000 m in length, and is wound up in a roll shape. Further, the width of the retardation film of the present embodiment is preferably 1 m or more, more preferably 1.4 m or more, and particularly preferably 1.4 to 4 m.
- the film thickness is preferably in the range of 10 to 36 ⁇ m from the viewpoint of thinning of the display device and productivity. If the film thickness is 10 ⁇ m or more, a certain level of film strength and retardation can be expressed. When the film thickness is 36 ⁇ m or less, the film has a desired phase difference and can be applied to thin the polarizing plate and the display device. Preferably, it is in the range of 20 to 36 ⁇ m.
- Table 1 shows various properties of retardation films produced as examples and comparative examples.
- “part” or “%” is used, but “part by mass” or “% by mass” is expressed unless otherwise specified.
- the retardation film of Example 1 was produced according to the following method.
- Fine particle addition liquid 1 The fine particle dispersion 1 was slowly added to the dissolution tank containing methylene chloride with sufficient stirring. Further, the particles were dispersed by an attritor so that the secondary particles had a predetermined particle size. This was filtered through Finemet NF manufactured by Nippon Seisen Co., Ltd. to prepare a fine particle additive solution 1.
- a main dope having the following composition was prepared. First, methylene chloride and ethanol were added to the pressure dissolution tank. Cellulose acetate butyrate having an acetyl group substitution degree of 2.6 and a butyryl group substitution degree of 0.28 was charged into a pressure dissolution tank containing a solvent while stirring. This was heated and dissolved completely with stirring. This was designated as Azumi Filter Paper No. The main dope was prepared by filtration using 244.
- the dope was prepared by putting the above into a sealed main dissolution kettle and dissolving with stirring.
- the solvent was evaporated until the residual solvent amount of the web of the retardation film cast (cast) on the stainless steel belt support reached 75%, and then the web was peeled off from the stainless steel belt support with a peeling tension of 130 N / m. .
- the peeled retardation film (web) was stretched 30% in the width direction using a tenter while applying heat at 150 ° C. The residual solvent at the start of stretching was 15%.
- Example 2 Hereinafter, retardation films of Example 24 and Comparative Examples 1 to 8 were produced in the same manner as in Example 1 above. That is, the acetyl group substitution degree and butyryl group substitution degree, retardation increasing agent, and additive of cellulose acetate butyrate were changed as shown in Table 1, and retardation films were respectively produced.
- R3 Exemplary compound 176 of the retardation increasing agent
- R4 Exemplary compound 383 of the retardation increasing agent
- R5 9H-carbazole-9-ethanol
- R represents an aliphatic alcohol group having 1 to 20 carbon atoms.
- R6 n-hexylcarbazole
- R represents an aryl group having 6 to 20 carbon atoms, each containing or not containing a heteroatom.
- R ′ represents hydrogen or an aliphatic alkyl group having 1 to 20 carbon atoms.
- R7 2,3-diphenylquinoxaline
- R represents a substituted or unsubstituted aliphatic group having 1 to 20 carbon atoms or a substituted or unsubstituted aromatic group having 6 to 20 carbon atoms.
- R8 2-methylbenzoxazole
- R and R ′ each represents an aliphatic alkyl group having 1 to 20 carbon atoms. The difference in molecular weight between R and R ′ is 20-200.
- R9 2- (4-tert-butylphenyl) -5- (4-biphenyl) -1,3,4-oxadiazole
- R ′′ represents an aliphatic alkyl group having 1 to 20 carbon atoms.
- R12 Japanese Patent No. 3896404 The retardation increasing agent of Example 1 (no nitrogen atom)
- cyclohexane of N8 is substituted with trans at positions 1 and 4.
- R14 Japanese Patent No. 4234823 The retardation increasing agent of Example 1 (no nitrogen atom)
- the retardation value of the retardation film is defined by the in-plane retardation value Ro defined by the equation (12) and the equation (13) at a measurement wavelength of 590 nm in an environment of a temperature of 23 ° C. and a relative humidity of 55% RH.
- the retardation value Rth in the thickness direction was measured using an automatic birefringence meter Axoscan (manufactured by Axometrics).
- a three-dimensional refractive index measurement was performed on the produced retardation film at 10 locations at a measurement wavelength of 590 nm in an environment of a temperature of 23 ° C. and a relative humidity of 55% RH. Then, after obtaining the average values of the refractive indexes nx , ny , and nz , the in-plane direction retardation value Ro and the thickness direction retardation value Rth were calculated according to the formulas (12) and (13). .
- the in-plane retardation value Ro is in the range of 25 to 53 nm, and the retardation value Rth in the thickness direction is It was within the range of 110 to 140 nm.
- the photoelastic coefficient of the retardation film can be measured by the following procedure.
- the retardation film is stored for 24 hours in an environment of a temperature of 23 ° C. and a relative humidity of 55% RH. Then, in a state where a tensile load is applied in the maximum stretching direction of the film (the direction in which the stretching ratio is maximum) under an environment of a temperature of 23 ° C. and a relative humidity of 55% RH, the phase difference in the in-plane direction of the film at a measurement wavelength of 590 nm
- the value Ro is measured by KOBURA31PR (manufactured by Oji Scientific Instruments).
- the retardation value Ro in the in-plane direction of the retardation film at each tensile load is measured.
- the horizontal axis is the tensile load
- a tensile load ⁇ n curve is obtained.
- the slope of the straight line when the obtained curve is approximated to a straight line is defined as the photoelastic coefficient.
- Evaluation of color unevenness of the retardation film can be performed by the following procedure.
- the produced vertical alignment type liquid crystal display device was laid and placed on a table or the like, and Bencot (manufactured by Asahi Kasei Fibers) was placed on a part of the polarizing plate for evaluation to contain water. Covered with 100 ⁇ m PET so that the bencott does not dry, input a black display signal from the personal computer to the vertical alignment type liquid crystal display device, and left it for 24 hours with the power supply of the vertical alignment type liquid crystal display device turned on (room temperature is 23 ° C.) Setting and display panel temperature is 38 ° C).
- A 0 or more and 1.0 or less: No occurrence of color unevenness is observed at all.
- ⁇ More than 1.0 and 1.50 or less: Although slightly weak color unevenness is observed, the quality has no practical problem.
- ⁇ More than 1.50 and 2.4 or less: Although slight color unevenness is observed, it is a level with no practical problem.
- ⁇ More than 2.4: Strong color unevenness occurs, and the quality has a problem with moisture resistance.
- Evaluation of durability according to wet heat dimensional fluctuation of the retardation film can be performed by the following procedure.
- a sample of a retardation film was cut into a size of 120 mm ⁇ 120 mm, and a cross-shaped mark was marked on the surface of the film sample with a sharp blade such as a razor at intervals of about 100 mm in the casting direction.
- the film sample was conditioned for 24 hours or more in an environment of a temperature of 23 ° C. and a relative humidity of 55% RH, and the distance L1 between the marks in the casting direction before the treatment was measured with a microscope.
- the film sample was subjected to high-temperature and high-humidity treatment for 120 hours in an environment of a temperature of 60 ° C. and a relative humidity of 90% RH using an electric thermostat.
- the film sample subjected to the high temperature and high humidity treatment was again conditioned for 24 hours in an environment of a temperature of 23 ° C. and a relative humidity of 55% RH, and the distance between marks L2 in the casting direction after the treatment was measured with a microscope.
- the rate of change before and after this treatment was determined by the following equation to calculate the rate of change in dimensions.
- Evaluation of durability according to the wet heat phase difference fluctuation of the retardation film can be performed by the following procedure.
- the sample of the retardation film was conditioned for 24 hours or more in an environment of a temperature of 23 ° C. and a relative humidity of 55% RH, and the retardation R1 was measured.
- the film sample was subjected to high-temperature and high-humidity treatment for 120 hours in an environment of a temperature of 60 ° C. and a relative humidity of 90% RH using an electric thermostat.
- the film sample subjected to the high temperature and high humidity treatment was again conditioned for 24 hours in an environment of a temperature of 23 ° C. and a relative humidity of 55% RH, and the phase difference R2 was measured.
- the rate of change before and after this treatment was determined by the following equation to calculate the rate of change in phase difference.
- the retardation films of all the examples satisfied at least a level of no practical problem. Furthermore, regarding the durability related to the wet heat dimensional fluctuation and the wet heat phase difference fluctuation, it was confirmed that the retardation films of all the examples were improved with respect to the retardation film of the comparative example. In particular, it was confirmed that the retardation films of Examples 1, 12, 13, 14, and 21 were able to realize good performance with respect to all the evaluations of color unevenness, wet heat dimensional variation, and wet heat phase difference variation. .
- the photoelastic coefficient of the retardation film may be 7.0 ⁇ 10 ⁇ 13 to 25.0 ⁇ 10 ⁇ 13 cm 2 / dyn (the upper limit is 24.0 ⁇ 10 ⁇ ).
- the value between 13 cm 2 / dyn and 27.0 ⁇ 10 ⁇ 13 cm 2 / dyn is adopted) and the range is 12.0 ⁇ 10 ⁇ 13 to 15.0 ⁇ 10 ⁇ 13 cm 2 / dyn
- desirable results can be obtained for at least one of color unevenness and wet heat durability.
- the film thickness of the retardation film is 38 ⁇ m
- the in-plane direction retardation Ro is 25 to 53 nm
- the thickness direction retardation Rth is 110 to 140 nm. Is 20 to 45 ⁇ m
- the in-plane direction phase difference Ro is 10 to 150 nm
- the thickness direction phase difference Rth is 30 to 400 nm. It was done.
- the present invention can be used in a retardation film, a polarizing plate having a retardation film, and a vertical alignment type liquid crystal display device.
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Abstract
Description
リタデーション上昇剤と、
を含み、
温度23℃、相対湿度55%RHの環境下、測定波長590nmにおいて、
光弾性係数が7.0×10-13~25.0×10-13cm2/dynの範囲であり、
面内方向の位相差Roが10~150nmであり、
厚さ方向の位相差Rthが30~400nmであり、
膜厚が20~45μmである
ことを特徴とする位相差フィルム。
式(1) 1.8≦X+Y≦2.9
式(2) 0.03≦Y≦0.8
(式中、Xはアセチル基の置換度を表し、Yはブチリル基の置換度を表す。)
本実施形態では、薄膜の構成で湿熱耐久性を保持しながら、吸湿によるリタデーション変動を抑制するために、位相差フィルムを以下のように構成している。すなわち、本実施形態の位相差フィルムは、セルロースエステルと、リタデーション上昇剤と、を含み、温度23℃、相対湿度55%RHの環境下、測定波長590nmにおいて、光弾性係数が7.0×10-13~25.0×10-13cm2/dyn(=7.0×10-12~25.0×10-12/Pa=7.0×10-12~25.0×10-12m2/N)の範囲であり、面内方向の位相差Roが10~150nmであり、厚さ方向の位相差Rthが30~400nmであり、膜厚が20~45μmである。なお、セルロースエステルは、置換度に関して、1.8≦X+Y≦2.9、0.03≦Y≦0.8(Xはアセチル基の置換度を表し、Yはブチリル基の置換度を表す)をともに満たす。
図1は本実施形態に係る垂直配向型(VA型;Vertical Alignment)液晶表示装置の概略構成を示す断面図である。垂直配向型液晶表示装置1は液晶表示パネル2及びバックライト3を備える。バックライト3は液晶表示パネル2を照明するための光源である。
本実施形態の位相差フィルムは、セルロースエステルと、リタデーション上昇剤と、を含み、温度23℃、相対湿度55%RHの環境下、測定波長590nmにおいて、光弾性係数が7.0×10-13~25.0×10-13cm2/dynの範囲であり、面内方向の位相差Roが10~150nmであり、厚さ方向の位相差Rthが30~400nmであり、膜厚が20~45μmである。これら諸要素の詳細については後述する実施例にて説明する。
光弾性とは、等方性の物質に外力を加えて内部に応力を起こさせると、光学異方性を呈して複屈折を示す現象を意味する。物質に作用する応力(単位面積当たりの力)をσとし、複屈折をΔnとした場合に、応力σと複屈折Δnは理論的には比例関係にあって、Δn=Cσと表すことができ、このCが光弾性係数である。言い換えれば、物質に作用する応力σを横軸に取り、その応力が作用したときの物質の複屈折Δnを縦軸にとると、理論的には両者の関係は直線となり、この直線の勾配が光弾性係数Cである。光弾性係数は、位相差フィルムを構成する樹脂及び添加剤の種類やその含有量を調整することによって調整することができる。
セルロースエステルは、セルロースアセテートブチレートからなる。セルロースアセテートブチレートはアセチル基の置換度をXとし、ブチリル基の置換度をYとした場合に、下記(1)及び(2)をともに満たすものであることが好ましい。なお、これら置換度の測定方法はASTM-D817-96に準じて測定することができる。
式(1) 1.8≦X+Y≦2.9
式(2) 0.03≦Y≦0.8
本実施形態のリタデーション上昇剤とは、セルロースエステル100質量部に対して当該化合物を3質量部含有した位相差フィルムの厚さ方向の位相差値Rth(測定波長590nm)が未添加の位相差フィルムと比べて1.1倍以上の値を示す機能を有する化合物をいう。
本実施形態のリタデーション上昇剤は、下記一般式(4)で表される構造を有する含窒素複素環化合物であることが好ましい。
一般式(4)で表される構造を有する化合物は、一般式(5)で表される構造を有する化合物であることが好ましい。
一般式(4)で表される構造を有する化合物は、下記一般式(6)で表される構造を有するトリアゾール化合物であることが好ましい。
例えば、例示化合物1は以下のスキームによって合成することができる。
例示化合物6は以下のスキームによって合成することができる。
例示化合物176は以下のスキームによって合成することができる。
本実施形態に係る前記一般式(3)~(5)で表される構造を有する化合物は適宜量を調整して位相差フィルムに含有することができるが、添加量としては位相差フィルム中に、0.1~10質量%含むことが好ましく、特に1~5質量%含むことが好ましく、さらに2~5質量%含むことがより好ましい。添加量はセルロースアセテートの種類、当該化合物の種類によって異なるものであるが、本実施形態の位相差フィルムが所望の位相差値を示す添加量によって最適値を決定することができる。この範囲内であれば、本実施形態の位相差フィルムの機械強度を損なうことなく、環境湿度の変化に依存したリタデーションの変動を低減することができる。
本実施形態では、上記した化合物のほかに、以下の公知文献で開示された化合物もリタデーション上昇剤として使用することができる。例えば、特許第5156067号公報、特許第3896404号公報、特許第4076454号公報、特許第4234823号公報、特開2012-82235号公報、韓国公開特許第2011-0075492号公報、韓国公開特許第2011-0037289号公報、韓国公開特許第10-2011-0075473号公報、韓国公開特許第2011-0075199号公報、韓国公開特許第2011-0071493号公報、で開示された化合物をリタデーション上昇剤として用いることも可能である。
本実施形態の位相差フィルムはその他の添加剤を含有することも好ましく、その例としては可塑剤、酸化防止剤、紫外線吸収剤、光安定剤、帯電防止剤、及び剥離剤などが挙げられる。より効果的に用いられる化合物は好ましくは可塑剤を含有することであり、なかでも以下に説明する糖エステル、またはジカルボン酸とジオールを反応させて得られる繰り返し単位を含む重縮合エステルを用いることが、セルロースエステルとの相溶性に優れ、高湿度下における水分の出入りを制御して位相差値変動を低減し、併せてケン化液のフィルムへの浸透を制御してケン化適性を向上する観点から好ましい。
〈糖エステル〉
本実施形態の位相差フィルムに用いる糖エステルとしては、ピラノース環またはフラノース環の少なくとも1種を1個以上12個以下有し、その構造のOH基の全て若しくは一部をエステル化した糖エステルであることが好ましい。本実施形態に係る糖エステルは加水分解防止の目的においても添加されることが好ましい。
以下に、本実施形態に好適に用いることのできる糖エステルの合成の一例を示す。
本実施形態の位相差フィルムに用いる重縮合エステルとしては、下記一般式(9)で表される構造を有する重縮合エステルを用いることが好ましい。
エチレングリコール180g、無水フタル酸278g、アジピン酸91g、安息香酸610g、エステル化触媒としてテトライソプロピルチタネート0.191gを、温度計、撹拌器、緩急冷却管を備えた2Lの四つ口フラスコに仕込み、窒素気流中230℃になるまで、撹拌しながら徐々に昇温する。重合度を観察しながら脱水縮合反応させた。反応終了後200℃で未反応のエチレングリコールを減圧留去することにより、重縮合エステルP1を得た。酸価0.20、数平均分子量450であった。
1,2-プロピレングリコール251g、無水フタル酸103g、アジピン酸244g、安息香酸610g、エステル化触媒としてテトライソプロピルチタネート0.191gを、温度計、撹拌器、緩急冷却管を備えた2Lの四つ口フラスコに仕込み、窒素気流中230℃になるまで、撹拌しながら徐々に昇温する。重合度を観察しながら脱水縮合反応させた。反応終了後200℃で未反応の1,2-プロピレングリコールを減圧留去することにより、下記重縮合エステルP2を得た。酸価0.10、数平均分子量450であった。
1,4-ブタンジオール330g、無水フタル酸244g、アジピン酸103g、安息香酸610g、エステル化触媒としてテトライソプロピルチタネート0.191gを、温度計、撹拌器、緩急冷却管を備えた2Lの四つ口フラスコに仕込み、窒素気流中230℃になるまで、撹拌しながら徐々に昇温する。重合度を観察しながら脱水縮合反応させた。反応終了後200℃で未反応の1,4-ブタンジオールを減圧留去することにより、重縮合エステルP3を得た。酸価0.50、数平均分子量2000であった。
1,2-プロピレングリコール251g、テレフタル酸354g、安息香酸610g、エステル化触媒としてテトライソプロピルチタネート0.191gを、温度計、撹拌器、緩急冷却管を備えた2Lの四つ口フラスコに仕込み、窒素気流中230℃になるまで、撹拌しながら徐々に昇温する。重合度を観察しながら脱水縮合反応させた。反応終了後200℃で未反応の1,2-プロピレングリコールを減圧留去することにより、重縮合エステルP4を得た。酸価0.10、数平均分子量400であった。
1,2-プロピレングリコール251g、テレフタル酸354g、p-トロイル酸680g、エステル化触媒としてテトライソプロピルチタネート0.191gを、温度計、撹拌器、緩急冷却管を備えた2Lの四つ口フラスコに仕込み、窒素気流中230℃になるまで、撹拌しながら徐々に昇温する。重合度を観察しながら脱水縮合反応させた。反応終了後200℃で未反応の1,2-プロピレングリコールを減圧留去することにより、下記重縮合エステルP5を得た。酸価0.30、数平均分子量400であった。
180gの1,2-プロピレングリコール、292gのアジピン酸、エステル化触媒としてテトライソプロピルチタネート0.191gを、温度計、撹拌器、緩急冷却管を備えた2Lの四つ口フラスコに仕込み、窒素気流中200℃になるまで、撹拌しながら徐々に昇温する。重合度を観察しながら脱水縮合反応させた。反応終了後200℃で未反応の1,2-プロピレングリコールを減圧留去することにより、重縮合エステルP6を得た。酸価0.10、数平均分子量400であった。
180gの1,2-プロピレングリコール、無水フタル酸244g、アジピン酸103g、エステル化触媒としてテトライソプロピルチタネート0.191gを、温度計、撹拌器、緩急冷却管を備えた2Lの四つ口フラスコに仕込み、窒素気流中200℃になるまで、撹拌しながら徐々に昇温する。重合度を観察しながら脱水縮合反応させた。反応終了後200℃で未反応の1,2-プロピレングリコールを減圧留去することにより、重縮合エステルP7を得た。酸価0.10、数平均分子量320であった。
エチレングリコール251g、無水フタル酸244g、コハク酸120g、酢酸150g、エステル化触媒としてテトライソプロピルチタネート0.191gを、温度計、撹拌器、緩急冷却管を備えた2Lの四つ口フラスコに仕込み、窒素気流中200℃になるまで、撹拌しながら徐々に昇温する。重合度を観察しながら脱水縮合反応させた。反応終了後200℃で未反応のエチレングリコールを減圧留去することにより、重縮合エステルP8を得た。酸価0.50、数平均分子量1200であった。
上記重縮合エステルP2と同様の製造方法で、反応条件を変化させて、酸価0.10、数平均分子量315の重縮合エステルP9を得た。
また、他の可塑剤の例としては多価アルコールエステル、多価カルボン酸エステル(フタル酸エステルを含む)、グリコレート化合物、及び脂肪酸エステルやリン酸エステルなどが挙げられる。これらは単独で用いても良いし、2種類以上を組み合わせて用いても良い。
酸化防止剤は劣化防止剤とも呼ばれる。高湿高温の環境下に液晶画像表示装置などが置かれた場合には位相差フィルムの劣化が起こる場合がある。
本実施形態の位相差フィルムは紫外線吸収機能を付与することを目的として、紫外線吸収剤を含有することができる。
本実施形態の位相差フィルムは表面の滑り性を高めるため、必要に応じて微粒子(マット剤)をさらに含有しても良い。
本実施形態の位相差フィルムは、例えば溶液流延法によって製造することができる。
以下、本実施形態の位相差フィルムを溶液流延法で製造する例について説明する。
溶解工程は、セルロースエステルに対する良溶媒を主とする有機溶媒に、溶解釜中で当該セルロースエステル、場合によって、本実施形態に係るリタデーション上昇剤、糖エステル、重縮合エステル、その他の化合物を撹拌しながら溶解しドープを形成する工程、或いは当該セルロースエステル溶液に、リタデーション上昇剤、糖エステル、重縮合エステル、その他の化合物溶液を混合して主溶解液であるドープを形成する工程である。
流延工程は、ドープを、送液ポンプ(例えば、加圧型定量ギヤポンプ)を通して加圧ダイに送液し、無限に移送する無端の金属支持体(例えば、ステンレスベルト、回転する金属ドラム等)の上の流延位置に、加圧ダイスリットからドープを流延する工程である。
溶媒蒸発工程は、ウェブ(流延用支持体上にドープを流延して形成されたドープ膜)を流延用支持体上で加熱し、溶媒を蒸発させる工程である。
剥離工程は、金属支持体上で溶媒が蒸発したウェブを剥離位置で剥離する工程である。剥離されたウェブはフィルムとして次工程に送られる。
乾燥工程は、金属支持体から剥離して得られたウェブを乾燥させる工程である。乾燥工程は予備乾燥工程、本乾燥工程に分けて行うこともできる。ウェブの乾燥はウェブを上下に配置した多数のローラーにより搬送しながら乾燥させても良いし、テンター乾燥機のようにウェブの両端部をクリップで固定して搬送しながら乾燥させても良い。
本実施形態の位相差フィルムは延伸処理することでフィルム内の分子の配向を制御することができ、目標とする面内方向の位相差値Ro、厚さ方向の位相差値Rthを得ることができる。
・流延方向に延伸→幅手方向に延伸→流延方向に延伸→流延方向に延伸
・幅手方向に延伸→幅手方向に延伸→流延方向に延伸→流延方向に延伸
(式中、d1は延伸後のセルロースエステルフィルムの前記延伸方向の幅寸法であり、d2は延伸前のセルロースエステルフィルムの前記延伸方向の幅寸法であり、tは延伸に要する時間(min)である。)
式(13) Rth={(nx+ny)/2-nz}×d(nm)
(式中、nxはフィルムの面内方向において屈折率が最大になる方向xにおける屈折率を表す。nyはフィルムの面内方向において前記方向xと直交する方向yにおける屈折率を表す。nzはフィルムの厚さ方向zにおける屈折率を表す。dはフィルムの厚さ(nm)を表す。)
所定の熱処理または冷却処理の後、巻取り前にスリッターを設けて端部を切り落とすことが良好な巻姿を得るため好ましい。さらに、幅手両端部にはナーリング加工をすることが好ましい。
ウェブ中の残留溶媒量が2質量%以下となってからフィルムとして巻取る工程である。残留溶媒量を0.4質量%以下にすることにより寸法安定性の良好なフィルムを得ることができる。
〈ヘイズ〉
本実施形態の位相差フィルムはヘイズが1%未満であることが好ましく、0.5%未満であることがより好ましい。ヘイズを1%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、光学用途のフィルムとしてより使用し易くなるという利点がある。
本実施形態の位相差フィルムは温度25℃、相対湿度60%RHにおける平衡含水率が4%以下であることが好ましく、3%以下であることがより好ましい。平衡含水率を4%以下とすることにより、湿度変化に対応し易く、光学特性や寸法がより変化し難く好ましい。
本実施形態の位相差フィルムは長尺であることが好ましく、具体的には100~10000m程度の長さであることが好ましく、ロール状に巻き取られる。また、本実施形態の位相差フィルムの幅は1m以上であることが好ましく、さらに好ましくは1.4m以上であり、特に1.4~4mであることが好ましい。
メチレンクロライドを入れた溶解タンクに十分撹拌しながら、微粒子分散液1をゆっくりと添加した。さらに、二次粒子の粒径が所定の大きさとなるようにアトライターにて分散を行った。これを日本精線(株)製のファインメットNFで濾過し、微粒子添加液1を調製した。
微粒子分散液1 5質量部
メチレンクロライド 365質量部
エタノール 50質量部
セルロースアセテートブチレート 100質量部
リタデーション上昇剤R3 2質量部
糖エステルS2 11質量部
重縮合エステルP5 7質量部
表1に記号で示したリタデーション上昇剤、添加剤について下記に述べる。
S2:糖エステル;BzSc(ベンジルサッカロース:段落〔0126〕に記載の糖残基がB-2であり、置換基がa1~a4である混合物)、平均エステル置換度=7.2
P5:前記重縮合エステル合成例で示した重縮合エステルP5
〈リタデーション値の測定〉
位相差フィルムのリタデーション値は温度23℃、相対湿度55%RHの環境下、測定波長590nmにおいて、前記式(12)により定義される面内方向の位相差値Ro及び前記式(13)により定義される厚さ方向の位相差値Rthを、自動複屈折率計アクソスキャン(アクソメトリックス社製)を用いて測定した。
位相差フィルムの光弾性係数の測定は以下の手順で行うことができる。
位相差フィルムの色ムラの評価は以下の手順で行うことができる。
○:1.0超1.50以下:ごく僅かに弱い色ムラの発生が認められるが、実用上問題のない品質である。
△:1.50超2.4以下:色ムラの発生が僅かに認められるが、実用上問題のないレベルである。
×:2.4超:強い色ムラが発生し、耐湿性に問題のある品質である。
位相差フィルムの湿熱寸法変動に係る耐久性の評価は以下の手順で行うことができる。
◎:±0~0.4%
○:±0.5~0.8%
△:±0.9~1.2%
×:±1.3%以上
位相差フィルムの湿熱位相差変動に係る耐久性の評価は以下の手順で行うことができる。
◎:±4nm
○:±5~10nm
△:±11~18nm
×:±19nm 以上
2 液晶表示パネル
3 バックライト
4 液晶セル
5 偏光板
6 偏光板
13 光学フィルム(位相差フィルム)
Claims (5)
- 置換度に関する下記式(1)及び(2)をともに満たすセルロースエステルと、
リタデーション上昇剤と、
を含み、
温度23℃、相対湿度55%RHの環境下、測定波長590nmにおいて、
光弾性係数が7.0×10-13~25.0×10-13cm2/dynの範囲であり、
面内方向の位相差Roが10~150nmであり、
厚さ方向の位相差Rthが30~400nmであり、
膜厚が20~45μmである
ことを特徴とする位相差フィルム。
式(1) 1.8≦X+Y≦2.9
式(2) 0.03≦Y≦0.8
(式中、Xはアセチル基の置換度を表し、Yはブチリル基の置換度を表す。) - 前記リタデーション上昇剤が、含窒素複素環化合物であり、ピロール環、ピラゾール環、トリアゾール環またはイミダゾール環を有する化合物であることを特徴とする請求項1に記載の位相差フィルム。
- 請求項1~請求項3のいずれかに記載の位相差フィルムを備えることを特徴とする偏光板。
- 請求項4に記載の偏光板を備えることを特徴とする垂直配向型液晶表示装置。
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JP2006323329A (ja) * | 2004-09-14 | 2006-11-30 | Fujifilm Holdings Corp | セルロースアシレートフィルム、偏光板及び液晶表示装置 |
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