WO2014068893A1 - 位相差フィルム、円偏光板、及び画像表示装置 - Google Patents
位相差フィルム、円偏光板、及び画像表示装置 Download PDFInfo
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- WO2014068893A1 WO2014068893A1 PCT/JP2013/006222 JP2013006222W WO2014068893A1 WO 2014068893 A1 WO2014068893 A1 WO 2014068893A1 JP 2013006222 W JP2013006222 W JP 2013006222W WO 2014068893 A1 WO2014068893 A1 WO 2014068893A1
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- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
- C08J5/18—Manufacture of films or sheets
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C55/00—Shaping by stretching, e.g. drawing through a die; Apparatus therefor
- B29C55/02—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
- B29C55/04—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets uniaxial, e.g. oblique
- B29C55/045—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets uniaxial, e.g. oblique in a direction which is not parallel or transverse to the direction of feed, e.g. oblique
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- C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
- C09K11/02—Use of particular materials as binders, particle coatings or suspension media therefor
- C09K11/025—Use of particular materials as binders, particle coatings or suspension media therefor non-luminescent particle coatings or suspension media
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- C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
- C09K11/06—Luminescent, e.g. electroluminescent, chemiluminescent materials containing organic luminescent materials
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/30—Polarising elements
- G02B5/3025—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state
- G02B5/3033—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid
- G02B5/3041—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid comprising multiple thin layers, e.g. multilayer stacks
- G02B5/305—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid comprising multiple thin layers, e.g. multilayer stacks including organic materials, e.g. polymeric layers
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- G—PHYSICS
- G02—OPTICS
- 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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2001/00—Use of cellulose, modified cellulose or cellulose derivatives, e.g. viscose, as moulding material
- B29K2001/08—Cellulose derivatives
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2995/00—Properties of moulding materials, reinforcements, fillers, preformed parts or moulds
- B29K2995/0018—Properties of moulding materials, reinforcements, fillers, preformed parts or moulds having particular optical properties, e.g. fluorescent or phosphorescent
- B29K2995/0034—Polarising
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2301/00—Characterised by the use of cellulose, modified cellulose or cellulose derivatives
- C08J2301/08—Cellulose derivatives
- C08J2301/10—Esters of organic acids
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- C09K2211/00—Chemical nature of organic luminescent or tenebrescent compounds
- C09K2211/10—Non-macromolecular compounds
- C09K2211/1003—Carbocyclic compounds
- C09K2211/1014—Carbocyclic compounds bridged by heteroatoms, e.g. N, P, Si or B
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- C—CHEMISTRY; METALLURGY
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- C09K2211/00—Chemical nature of organic luminescent or tenebrescent compounds
- C09K2211/10—Non-macromolecular compounds
- C09K2211/1018—Heterocyclic compounds
- C09K2211/1022—Heterocyclic compounds bridged by heteroatoms, e.g. N, P, Si or B
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K2211/00—Chemical nature of organic luminescent or tenebrescent compounds
- C09K2211/10—Non-macromolecular compounds
- C09K2211/1018—Heterocyclic compounds
- C09K2211/1025—Heterocyclic compounds characterised by ligands
- C09K2211/1092—Heterocyclic compounds characterised by ligands containing sulfur as the only heteroatom
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
- G02F1/133528—Polarisers
- G02F1/133541—Circular polarisers
Definitions
- the present invention relates to a retardation film, a circularly polarizing plate, and an image display device.
- An organic electroluminescence element is a light source for a flat illumination device, a light source for an optical fiber, a backlight for a liquid crystal display, and a liquid crystal projector device from the viewpoint of high luminous efficiency, low voltage drive, light weight, and low cost.
- the use as a light source such as a light source of a backlight or an organic EL display (OLED) has been widely studied.
- a light emitting layer is provided between electrodes, and when a voltage is applied between the electrodes, electrons are injected from the cathode into the light emitting layer, and holes from the anode are injected into the light emitting layer.
- the light emitting layer emits light by the energy generated by the bonding.
- the organic EL element has an anode made of indium tin oxide (ITO) because of its high electrical conductivity, relatively high work function, and high hole injection efficiency among transparent conductive materials. , Mainly used.
- a metal electrode is usually used for the cathode.
- Mg, Mg / Ag, Mg / In, Al, Li / Al, etc. are mainly used from the viewpoint of work function in consideration of electron injection efficiency.
- These metal electrodes have a high light reflectivity, and in addition to the function as an electrode (cathode), they also have a function of reflecting the light emitted from the light emitting layer and increasing the amount of emitted light (light emission luminance).
- the amount of light (emission luminance) can be increased.
- the cathode of the organic EL element has a mirror surface with strong light reflectivity, external light reflection is likely to occur when light is not emitted. For this reason, in an apparatus using an organic EL element as a light source, for example, an organic EL display (OLED) or the like, reflection of indoor lighting or the like occurs, it is difficult to express black in a bright place, and contrast is reduced. There was a problem.
- OLED organic EL display
- optical films having various functions are used in apparatuses using organic EL elements as light sources.
- an optical film used in an apparatus using an organic EL element as a light source as described above, since the organic EL element is likely to reflect outside light in a state where it does not emit light, in order to prevent this reflection, polarized light is used.
- the retardation film that can be used to form a circularly polarizing plate having antireflection properties by bonding to a child.
- the retardation film for exhibiting such antireflection properties include a ⁇ / 4 retardation film whose in-plane retardation is about 1 ⁇ 4 of the wavelength ⁇ of transmitted light.
- examples of such a retardation film include retardation plates and films described in Patent Documents 1 to 4.
- Patent Document 1 a quarter-wave plate with an in-plane retardation imparted to transmitted light is a quarter wavelength, and a half-wave plate with an in-plane retardation of a half wavelength.
- a phase difference plate bonded in a state where the optical axes intersect is described.
- Patent Document 2 discloses an optically anisotropic layer A having an in-plane retardation of substantially ⁇ at a wavelength of 550 nm and an optical anisotropy having an in-plane retardation of substantially ⁇ / 2 at a wavelength of 550 nm.
- a retardation plate is described in which the layer B is laminated, and any one of the layers is a layer formed from liquid crystalline molecules.
- Patent Document 3 discloses a cellulose ester film containing a retardation control agent having a function of controlling retardation so that the refractive index of the cellulose ester film in a direction orthogonal to the stretching direction is increased when the cellulose ester film is uniaxially stretched.
- Patent Document 4 discloses that a molecular absorption wavelength derived from a transition electric dipole moment substantially perpendicular to the molecular long axis direction is a molecular absorption derived from a transition electric dipole moment substantially parallel to the molecular long axis direction.
- An optical film containing at least one raising agent is described.
- Patent Documents 1 to 4 disclose that a ⁇ / 4 phase difference can be realized.
- a retardation film having an in-plane retardation of ⁇ / 4 for example, when used for a circularly polarizing plate for imparting an antireflection function to an organic EL display, light that irradiates only light of a specific wavelength.
- an in-plane phase difference is required to be about 1/4 of the wavelength for light in the entire visible light wavelength range. Therefore, the phase difference imparted to the long wavelength light is larger than the phase difference imparted to the short wavelength light. It is required to do.
- the retardation film is required not only to have an in-plane retardation of about 1 ⁇ 4 of the wavelength with respect to light in the entire visible light wavelength range, but also to reduce the thickness of the film in order to satisfy the requirements for downsizing the apparatus. It has been.
- the present invention provides a retardation film that sufficiently suppresses deterioration of brittleness, is excellent in transparency, and has an in-plane retardation of about 1 ⁇ 4 of the wavelength with respect to light in a wide range of visible light wavelengths.
- the purpose is to do.
- it aims at providing the circularly-polarizing plate and image display apparatus provided with the said retardation film.
- One aspect of the present invention is a long retardation film containing a cellulose acylate resin and an additive, wherein the additive is an additive represented by the following general formula (A), and absorbs light.
- the degree of orientation of the cellulose acylate resin, calculated by spectroscopy, is 0.03 or more and 0.15 or less, and the degree of orientation of the additive, calculated by absorption spectroscopy, is greater than 0.15
- An in-plane retardation value of the retardation film at a wavelength of 550 nm is 115 nm or more and 160 nm or less, and an angle formed by an in-plane slow axis of the retardation film and a longitudinal direction of the retardation film is 15 It is a retardation film characterized by being at least 85 ° and at most 85 °.
- Q represents an aromatic hydrocarbon ring, a non-aromatic hydrocarbon ring, an aromatic heterocyclic ring, or a non-aromatic heterocyclic ring
- Wa and Wb represent the Q ring.
- a hydrogen atom or a substituent bonded to the constituent atoms, the atom bonded to Wa and the atom bonded to Wb are adjacent to each other in the ring of Q, and Wa and Wb are different , Wa and Wb may form a ring
- R 1 and R 2 each independently represent a substituent
- R 3 represents a substituent
- the degree of substitution m is 0-2.
- Another aspect of the present invention is a circularly polarizing plate provided with the retardation film.
- Another aspect of the present invention is an image display device including the retardation film.
- FIG. 1 is a schematic diagram for explaining the shrinkage ratio in oblique stretching.
- FIG. 2 is a schematic view showing an example of a rail pattern of an oblique stretching machine that can be applied to manufacture of a retardation film according to an embodiment of the present invention.
- FIG. 3 is a schematic diagram illustrating a method for producing a retardation film according to an embodiment of the present invention (an example in which the film is drawn from a long film original fabric roll and then obliquely stretched).
- FIG. 4 is a schematic view showing a method for producing a retardation film according to an embodiment of the present invention (an example in which a long film original is continuously stretched obliquely without being wound up).
- FIG. 5 is a schematic diagram showing an example of the configuration of the organic EL display device according to the embodiment of the present invention.
- the retardation plates and films described in Patent Documents 1 to 4 are sufficient that the phase difference is about 1 ⁇ 4 of the wavelength with respect to the light in the entire visible light wavelength range.
- the retardation plates described in Patent Document 1 and Patent Document 2 are difficult to reduce in thickness because two or more different plates and layers are laminated. Moreover, since it is necessary to laminate
- the circularly polarizing plate as described above is bonded in such a manner that the in-plane slow axis of the retardation film is inclined at a desired angle such as 45 ° with respect to the absorption axis of the polarizer.
- the polarizer is generally obtained by stretching at a high magnification in the longitudinal direction, the absorption axis formed by the stretching often coincides with the longitudinal direction. Therefore, when a retardation film that is obliquely stretched so that the in-plane slow axis is inclined at a desired angle such as 45 ° with respect to the longitudinal direction is used as the retardation film, A circularly polarizing plate can be produced by continuously laminating a retardation film and a long polarizer. For this reason, a retardation film obtained by oblique stretching has attracted attention.
- the present invention has been made in view of such circumstances, and even a cellulose acylate film having a sufficiently thin thickness sufficiently suppresses deterioration of brittleness, is excellent in transparency, and has a visible light wavelength.
- An object of the present invention is to provide a retardation film having an in-plane retardation of about 1 ⁇ 4 of the wavelength with respect to a wide range of light. Moreover, it aims at providing the circularly-polarizing plate and image display apparatus provided with the said retardation film.
- the retardation film according to an embodiment of the present invention is a long retardation film containing a cellulose acylate resin and an additive, and the additive is represented by the general formula (A).
- the degree of orientation of the cellulose acylate resin calculated by absorption spectroscopy is 0.03 or more and 0.15 or less, and the degree of orientation of the additive calculated by absorption spectroscopy is 0. Larger than .15, the in-plane retardation value of the retardation film at a wavelength of 550 nm is from 115 nm to 160 nm, and the in-plane slow axis of the retardation film and the longitudinal direction of the retardation film are The formed angle is 15 ° or more and 85 ° or less.
- a cellulose acylate film having a sufficiently thin thickness sufficiently suppresses deterioration of brittleness is excellent in transparency, and further, for light in a wide range of visible light wavelengths, A retardation film ( ⁇ / 4 retardation film) having an in-plane retardation value of about 1 ⁇ 4 of the wavelength is obtained.
- the breakage is sufficiently suppressed, it is considered that a film that is sufficiently thin and highly transparent and can realize a ⁇ / 4 retardation can be obtained. Further, the angle formed by the in-plane slow axis of the retardation film and the longitudinal direction of the retardation film is inclined as described above, whereby a circularly polarizing plate can be produced while maintaining the long shape.
- this retardation film when applied to an image display device such as an organic EL display, an image display device capable of displaying a good image with sufficient reflection of external light and the like can be obtained.
- the “ ⁇ / 4 retardation film” refers to a film having an in-plane retardation value of about 1 ⁇ 4 with respect to a predetermined light wavelength (usually a visible light region). .
- the in-plane retardation value in the visible light wavelength range is approximately 1 ⁇ 4 of the wavelength.
- a broadband ⁇ / 4 retardation film is preferable.
- “the phase difference having an in-plane retardation value of approximately 1 ⁇ 4 in the visible light wavelength range” means that the in-plane retardation value increases in the wavelength range of 400 to 700 nm as the wavelength increases. It means having a large inverse wavelength dispersion characteristic.
- the degree of orientation Spol of the cellulose acylate resin is 0.03 or more and 0.15 or less, preferably 0.05 or more and 0.15 or less, and 0.07 or more and 0.14 or less. It is more preferable that If the degree of orientation Spol of the cellulose acylate resin is within the above range, it is possible to sufficiently realize the ⁇ / 4 phase difference by increasing the degree of orientation Sa of the additive while sufficiently suppressing the decrease in brittleness. .
- orientation degree Spol of the cellulose acylate resin can be adjusted by the following.
- the orientation degree Spol of the cellulose acylate resin can be adjusted by the composition of the cellulose acylate resin or the like. More specifically, the lower the total acyl group substitution degree, the smaller the Spol tends to be. In addition, as a substituent, a bulky acyl group or a large acyl group tends to have a smaller Spol, and conversely, a shorter or three-dimensionally smaller acyl group tends to have a larger Spol. is there.
- the orientation degree Spol of the cellulose acylate resin can be adjusted by the type of the plasticizer and the amount of the plasticizer added.
- the orientation of the cellulose acylate resin The degree Spol tends to be smaller than when no plasticizer is added.
- the degree of decrease in the degree of orientation Spol of the cellulose acylate resin is small.
- the degree of orientation Spol of the cellulose acylate resin tends to decrease as the amount of plasticizer added increases.
- the orientation degree Spol of the cellulose acylate resin can be adjusted according to the stretching conditions for producing the retardation film. For example, when the stretching temperature is increased, Spol tends to decrease. Conversely, when the stretching temperature is lowered, Spol tends to increase. Moreover, when the draw ratio is increased, generally, Spol tends to increase. Conversely, when the draw ratio is lowered, Spol tends to be smaller.
- the degree of orientation Sa of the additive is greater than 0.15.
- the degree of orientation Sa of the additive is preferably as large as possible, but in reality, about 1 is the upper limit, so 1 is the upper limit.
- the orientation degree Sa of the additive is preferably greater than 0.15, preferably 0.16 or more and 0.5 or less, and more preferably 0.16 or more and 0.4 or less. If the orientation degree Sa of the additive is within the above range, a ⁇ / 4 phase difference can be realized with a thin film.
- the degree of orientation Sa of the additive can be adjusted by the following.
- the orientation degree Sa of the additive can be adjusted by the chemical structure of the additive. Specifically, in the structure represented by the general formula (A), when the linearity of the partial structure represented by R 1 -L 1- (QL 2 ) n -R 2 is high and rigid, Sa Tend to grow.
- the Q moiety is an aromatic hydrocarbon ring, a non-aromatic hydrocarbon ring, an aromatic heterocycle, or a non-aromatic heterocycle
- the R 1 and R 2 moieties are cyclo An alkyl group (such as a cyclohexyl group, a cyclopentyl group, and a 4-n-dodecylcyclohexyl group), a cycloalkenyl group (such as a 2-cyclopenten-1-yl and 2-cyclohexen-1-yl group), an aryl group (a phenyl group, p-tolyl group, naphthyl group, etc.), heteroaryl group (2-furyl group, 2-thienyl group, 2-pyrimidinyl group, 2-benzothiazolyl group, 2-pyridyl group, etc.), aryloxy group (phenoxy group, 2-methylphenoxy group, 4-tert-butylphenoxy group, 3-nitrophenoxy group,
- L 1 and L 2 are —O— group, — (C ⁇ O) —O— group, —O— (C ⁇ O) — group, — (C ⁇ O) —NH— group, —NH
- Sa tends to be larger.
- each orientation degree of the orientation degree Spol of the cellulose acylate resin and the orientation degree Sa of the additive is a value calculated by absorption spectroscopy, and can be specifically measured by the following method. it can.
- a spectrophotometer that can use linearly polarized light as incident light in a wavelength range of 220 to 450 nm can be used. It can also be measured using a commercially available spectrophotometer (for example, V-7100 manufactured by JASCO Corporation) that supports a wavelength range of 220 to 450 nm.
- a polarizer corresponding to the ultraviolet region for example, Grand Taylor prism; extinction ratio 1 ⁇ 10 ⁇ 5
- an integrating sphere is installed on the detection side, the integrating sphere is removed and a commercially available depolarizing filter is installed instead.
- the film sample (F1) to be measured containing the additive is installed in the above apparatus, and the absorption spectrum is measured in the wavelength range of 220 to 450 nm.
- the spectrum is measured so that an arbitrary reference direction of the film (in the present invention, the slow axis direction of the film) coincides with the transmission axis of the polarizer, the spectrum is measured, and the absorption derived from the additive Absorbance Aa (P) is obtained.
- the sample was placed so that the arbitrary reference direction of the film was 90 ° with respect to the transmission axis of the polarizer, and the spectrum was measured in the same manner.
- Absorbance Aa (V) of absorption is obtained.
- the orientation degree Sa of the additive is calculated according to the following formula.
- Sa ⁇ Aa (V) -Aa (P) ⁇ / ⁇ Aa (V) + 2Aa (P) ⁇
- Sa 0 means that the orientation is random (that is, not oriented)
- Sa 1 means that the orientation is complete.
- the method for calculating the degree of orientation Spol of the cellulose acylate resin is as follows.
- the Spol calculation film sample (F2) is also the same stretching temperature condition and stretching ratio condition as the film sample (F1) for which Sa is calculated. Create by stretching.
- the same stretching temperature condition as (F1) means that the difference between the glass transition temperature of F1 and the actually stretched temperature is the same as the difference between the glass transition temperature of F2 and the actually stretching temperature. It means that the stretching temperature is selected so as to be.
- the prepared F2 is placed in a spectrophotometer in which a polarizer is disposed on the light source side, and the transmission axis of the polarizer and the reference direction of the film (in the present invention, the slow phase of the film
- the absorbance Apol (P) derived from azobenzene in the direction in which the (axis direction) matches and the absorbance Apol (V) when tilted by 90 ° are obtained.
- the orientation degree Spol of the cellulose acylate resin is calculated according to the following formula.
- the glass transition temperature (Tg) of the film may be determined by, for example, DSC-7 differential scanning calorimeter (Perkin Elmer) or TAC7 / DX thermal analyzer controller (Perkin Elmer) differential scanning calorimeter Q2000 (TA Instruments). It can be measured by a differential scanning calorimetric analysis method using a commercially available apparatus such as a differential scanning calorimeter DSC 6220 (manufactured by SEI Nano Technology Co., Ltd.).
- Heat-cool-heat control is performed under conditions of a measurement temperature of 30 to 240 ° C., a temperature increase rate of 5 ° C./min, and a temperature decrease rate of 10 ° C./min.
- a glass transition temperature is calculated
- the retardation film has an in-plane retardation value Ro (550) at a wavelength of 550 nm of 115 nm or more and 160 nm or less. Furthermore, the in-plane retardation value Ro (550) is preferably 120 nm or more and 160 nm or less, and more preferably 130 nm or more and 150 nm or less. A retardation film having Ro (550) within the above range can preferably function as a ⁇ / 4 retardation film.
- the retardation film preferably has a thickness direction retardation value Rth (550) at a wavelength of 550 nm of 50 nm or more and 250 nm or less.
- the retardation film has an in-plane retardation value Ro (450) at a wavelength of 450 nm, an in-plane retardation value Ro (550) at a wavelength of 550 nm, and an in-plane retardation value Ro (650) at a wavelength of 650 nm.
- the following formula (1) and the following formula (2) are preferably satisfied.
- Ro (450) / Ro (550) is preferably 0.72 or more and 0.94 or less, and preferably 0.79 or more and 0.91 or less, as described above. More preferably, it is 0.81 or more and 0.89 or less. Further, as described above, Ro (550) / Ro (650) is preferably 0.83 or more and 0.98 or less, more preferably 0.84 or more and 0.97 or less, and 0.85. More preferably, it is 0.95 or less.
- Ro ( ⁇ ) is the in-plane retardation value Ro at a wavelength ⁇ under the condition of 23 ° C. and 55% RH
- Rth ( ⁇ ) is the wavelength ⁇ under the condition of 23 ° C. and 55% RH.
- the thickness direction retardation value Rth is an in-plane retardation value Ro at a wavelength of 550 nm under the condition of 23 ° C. and 55% RH.
- Ro and Rth in the retardation film are defined by the following equations, respectively.
- Formula 2: Rth ⁇ (nx + ny) / 2 ⁇ nz ⁇ ⁇ d (nm)
- nx represents the refractive index in the slow axis direction x where the refractive index is maximum in the in-plane direction of the retardation film
- ny is the slow phase in the in-plane direction of the retardation film.
- the refractive index in the direction y orthogonal to the axial direction x is represented
- nz represents the refractive index in the thickness direction z of the retardation film
- d (nm) represents the thickness of the retardation film.
- Ro and Rth can be measured using an automatic birefringence meter.
- the automatic birefringence system include AxoScan manufactured by Axometrics, KOBRA-21ADH manufactured by Oji Scientific Instruments, and the like. Specifically, it can be measured by the following method.
- Ro (450), Ro (550) when light having a measurement wavelength of 450 nm, 550 nm, or 650 nm is incident on the retardation film after humidity control in parallel with the normal line of the film surface.
- Ro (650) is measured with an AxoScan manufactured by Axometrics.
- the slow axis in the plane of the retardation film can also be confirmed by AxoScan manufactured by Axometrics.
- phase difference R ( ⁇ ) when light having a measurement wavelength of 450 nm, 550 nm, or 650 nm is incident is measured.
- the phase difference R ( ⁇ ) can be measured at 6 points every 10 ° within a range of ⁇ from 0 ° to 50 °.
- nx, ny and nz are calculated by AxoScan manufactured by Axometrics. Then, based on the above formula, thickness direction retardations Rth (450), Rth (550) or Rth (650) at the measurement wavelengths of 450 nm, 550 nm or 650 nm are respectively calculated.
- Ro (450) / Ro (550) can be calculated from the obtained Ro (450) and Ro (550). Then, Ro (550) / Ro (650) can be calculated from the obtained Ro (550) and Ro (650).
- the retardation film has an in-plane slow axis and an elongated direction, that is, an in-plane orientation angle of 15 ° to 85 °, and 30 ° to 60 °. Preferably, it is 35 ° or more and 55 ° or less, and more preferably 40 ° or more and 50 ° or less.
- the film is unwound from the roll body and is unwound from the roll body and has a slow axis in an oblique direction with respect to the long direction, and is unwound from the roll body and parallel to the long direction
- a circularly polarizing plate can be easily produced by laminating a polarizer film having a transmission axis with a roll-to-roll so that the longitudinal directions thereof are overlapped with each other. Thereby, there is little cut loss of a film and it is advantageous on production.
- the retardation film includes a cellulose acylate resin and an additive. If the additive is an additive represented by the general formula (A), the retardation film may include other components. Good.
- the cellulose acylate resin used in the present embodiment is a compound obtained by esterifying cellulose and carboxylic acid. That is, the cellulose acylate resin is a compound obtained by dehydrating and condensing a cellulose hydroxyl group and a carboxyl group of a carboxylic acid to form an acyl group.
- the carboxylic acid is not particularly limited, and examples thereof include an aliphatic carboxylic acid having about 2 to 22 carbon atoms and an aromatic carboxylic acid having about 2 to 22 carbon atoms. Among these, lower fatty acids having 6 or less carbon atoms are preferable.
- carboxylic acid may be used independently, you may use it in combination of 2 or more type.
- the acyl group of the cellulose acylate resin is not particularly limited, and may be linear or branched. Moreover, the acyl group may have a cyclic structure and may have other substituents. When the total acyl substitution degree of the cellulose acylate resin is constant, the birefringence tends to decrease as the carbon number of the acyl group increases. Therefore, the carbon number of the acyl group is preferably 2 to 6, more preferably 2 to 4, and further preferably 2 to 3 from the viewpoint of transparency and the like.
- the cellulose acylate resin include mixed fatty acid esters such as cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate propionate butyrate, and cellulose acetate phthalate in addition to cellulose acetate such as triacetyl cellulose. Etc. Among these, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, and the like are preferable.
- the butyryl group that can be contained in the cellulose acylate resin may be linear or branched.
- the total substitution degree of acyl groups of the cellulose acylate resin can be about 1.5 to 3.
- the total substitution degree of the acyl group is preferably 1.5 to 2.5 from the viewpoint of enhancing the retardation development.
- the substitution degree of the acyl group having 3 or more carbon atoms is preferably 2 or less. When the substitution degree of the acyl group having 3 or more carbon atoms is within the above range, it is preferable from the viewpoint of retardation development.
- substitution degree of the acyl group of the cellulose acylate resin can be measured by a method prescribed in ASTM-D817-96.
- the total number of carbon atoms in the acyl group per glucose unit is preferably 6.5 or less, more preferably 4 to 6.3, and more preferably 4.4 to 6. More preferably, it is two.
- the total carbon number of the acyl group per glucose unit is the sum of the carbon number of the acyl group bonded to one glucose unit of the cellulose acylate resin.
- the acyl group total carbon number can be obtained using the following formula.
- DS (k) in this formula represents the degree of substitution of acyl group having k carbon atoms per glucose unit of the cellulose acylate resin.
- the acyl group is an acetyl group
- the number of carbon atoms is 2, and the degree of acetyl group substitution is represented as DS (2).
- the haze value of the obtained retardation film can be made suitable and sufficient transparency can be maintained.
- the molecular weight of the cellulose acylate resin such as weight average molecular weight (Mw) and number average molecular weight (Mn) is measured using gel permeation chromatography (GPC).
- Mw weight average molecular weight
- Mn number average molecular weight
- the content of residual sulfuric acid in the cellulose acylate resin is preferably in the range of 0.1 to 45 ppm by mass in terms of elemental sulfur, and more preferably in the range of 1 to 30 ppm by mass. Sulfuric acid is considered to remain in the film in a salt state. If the content of residual sulfuric acid exceeds 45 ppm by mass, the film tends to break when it is hot-stretched or when it is cut (slit) after heat-stretching.
- the content of residual sulfuric acid can be measured by the method prescribed in ASTM D817-96.
- the content of the free acid in the cellulose acylate resin is preferably 1 to 500 ppm by mass, more preferably 1 to 100 ppm by mass, and further preferably 1 to 70 ppm by mass.
- the content of free acid can be measured by the method prescribed in ASTM D817-96.
- the cellulose acylate resin may contain a trace amount of metal components. It is considered that the trace amount of the metal component is derived from water used in the cellulose acylate resin synthesis process. Like these metal components, the content of components that can become insoluble nuclei is preferably as small as possible.
- metal ions such as iron, calcium, and magnesium may form a salt with a resin decomposition product or the like that may contain an organic acidic group to form an insoluble material.
- the calcium (Ca) component easily forms a coordination compound (that is, a complex) with an acidic component such as a carboxylic acid or a sulfonic acid, and many ligands. Insoluble starch, turbidity) may be formed.
- the content of the iron (Fe) component in the cellulose acylate resin is preferably 1 mass ppm or less.
- the content of the calcium (Ca) component in the cellulose acylate resin is preferably 60 ppm by mass or less, more preferably 0 to 30 ppm by mass.
- the content of the magnesium (Mg) component in the cellulose acylate resin is preferably 0 to 70 ppm by mass, and particularly preferably 0 to 20 ppm by mass.
- the content of metal components such as iron (Fe) component, calcium (Ca) component, and magnesium (Mg) component is the same as that obtained by subjecting an absolutely dry cellulose acylate resin to microdigest wet decomposition equipment (sulfuric acid decomposition) and alkali melting. After the treatment, it can be measured using ICP-AES (Inductively Coupled Plasma Atomic Emission Spectrometer).
- the contents of residual alkaline earth metal, residual sulfuric acid and residual acid can be adjusted by thoroughly washing the cellulose acylate resin obtained by synthesis.
- the method for producing the cellulose acylate resin is not particularly limited as long as the cellulose acylate resin can be produced, and a known production method may be mentioned. Specifically, if an example is given, it can be synthesized with reference to the method described in JP-A-10-45804.
- the cellulose as a raw material of the cellulose acylate resin is not particularly limited, and may be cotton linter, wood pulp, kenaf, and the like.
- a cellulose acylate resin produced from a single raw material may be used, or two or more cellulose acylate resins of different raw materials may be used in combination.
- the additive used in the present embodiment is an additive represented by the general formula (A).
- Q in the general formula (A) represents an aromatic hydrocarbon ring, a non-aromatic hydrocarbon ring, an aromatic heterocycle, or a non-aromatic heterocycle.
- the aromatic hydrocarbon ring may be a single ring or a condensed ring, and is preferably a single ring.
- Preferred examples of the aromatic hydrocarbon ring include benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, perylene ring, tetracene ring, pyrene ring, benzopyrene ring, chrysene ring, triphenylene ring, acenaphthene ring, fluoranthene ring, and fluorene ring. And more preferably a benzene ring.
- the non-aromatic hydrocarbon ring may be a single ring or a condensed ring, and is preferably a single ring.
- Preferred examples of the non-aromatic hydrocarbon ring include a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a cycloheptane ring, a cyclooctane ring, a cyclobutene ring, a cyclopentene ring, a cyclohexene ring, a cycloheptene ring, and a cyclooctene ring.
- Preferred examples include a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a cycloheptane ring, a cyclooctane ring, a norbornene ring, and the like, more preferably a cyclohexane ring and a cyclopentane ring.
- the aromatic heterocyclic ring may be a monocyclic ring or a condensed ring, and is preferably a monocyclic ring.
- Preferred examples of the aromatic heterocycle include furan ring, benzofuran ring, thiophene ring, benzothiophene ring, pyrrole ring, pyrazole ring, imidazole ring, oxadiazole ring, indole ring, carbazole ring, azacarbazole ring (azacarbazole ring) Group represents one in which one or more carbon atoms constituting the carbazole ring group are replaced by nitrogen atoms), triazole ring, pyrroloimidazole ring, pyrrolopyrazole ring, pyrrolopyrrole ring, thienopyrrole ring, thienothiophene ring, fluropyrrole ring , Furofuran ring, thienofuran ring, benziso
- the non-aromatic heterocyclic ring may be a monocyclic ring or a condensed ring, and is preferably a monocyclic ring.
- Preferred examples of the non-aromatic heterocyclic ring include tetrahydrofuran ring, tetrahydropyran ring, dioxolane ring, dioxane ring, pyrrolidine ring, pyridone ring, pyridazinone ring, imide ring, piperidine ring, dihydropyrrole ring, dihydropyridine ring, tetrahydropyridine ring, Examples include a piperazine ring, a morpholine ring, a dihydrooxazole ring, a dihydrothiazole ring, a piperidine ring, an aziridine ring, an azetidine ring, an azepine ring, an azepan ring, an imidazolidine ring,
- Wa and Wb are a hydrogen atom or a substituent each bonded to an atom (ring atom) constituting the ring of Q.
- the atom to which Wa is bonded and the atom to which Wb are bonded are adjacent to each other in the Q ring. Wa and Wb are different from each other.
- Wa and Wb may be bonded to each other to form a ring. Moreover, at least one of Wa and Wb may have a ring structure.
- the ring structure is preferably an aromatic hydrocarbon ring, a non-aromatic hydrocarbon ring, an aromatic heterocycle or a non-aromatic heterocycle.
- Wa and Wb include, for example, the following substituents. Specifically, halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom; methyl group, ethyl group, n-propyl group, isopropyl group, tert-butyl group, n-octyl group, and 2-ethylhexyl Alkyl groups such as cycloalkyl groups; cycloalkyl groups such as cyclohexyl groups, cyclopentyl groups, and 4-n-dodecylcyclohexyl groups; alkenyl groups such as vinyl groups and allyl groups; 2-cyclopenten-1-yl groups, and 2-cyclohexene Cycloalkenyl groups such as -1-yl group; alkynyl groups such as ethynyl group and propargyl group; aryl groups such as phenyl group, p-tolyl group and
- R 1 and R 2 in the general formula (A) each independently represent a substituent.
- R 1 and R 2 may be the same or different from each other.
- R 1 and R 2 include the substituents shown below. Specifically, halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom; methyl group, ethyl group, n-propyl group, isopropyl group, tert-butyl group, n-octyl group, and 2-ethylhexyl Alkyl groups such as cycloalkyl groups; cycloalkyl groups such as cyclohexyl groups, cyclopentyl groups, and 4-n-dodecylcyclohexyl groups; alkenyl groups such as vinyl groups and allyl groups; 2-cyclopenten-1-yl groups, and 2-cyclohexene Cycloalkenyl groups such as -1-yl group; alkynyl groups
- R 1 and R 2 are an alkyl group (preferably an alkyl group having 1 to 20 carbon atoms), a cycloalkyl group (preferably a cycloalkyl group having 3 to 20 carbon atoms), an aryl group (preferably a carbon number of 6 Is preferably an aryl group having 20 to 20 carbon atoms, a heteroaryl group (preferably an aryl group having 4 to 20 carbon atoms), and more preferably an aryl group or a cycloalkyl group.
- the aryl group is preferably a substituted or unsubstituted phenyl group, more preferably a phenyl group having a substituent, and still more preferably a phenyl group having a substituent at the 4-position.
- the cycloalkyl group is preferably a substituted or unsubstituted cyclohexyl group, more preferably a cyclohexyl group having a substituent, and further preferably a cyclohexyl group having a substituent at the 4-position.
- the substituent represented by R 1 or R 2 may be further substituted with the above substituent.
- R 3 represents a substituent.
- R 3 include the following substituents. Specifically, hydrogen atom; halogen atom such as fluorine atom, chlorine atom, bromine atom and iodine atom; methyl group, ethyl group, n-propyl group, isopropyl group, tert-butyl group, n-octyl group, and Alkyl group such as 2-ethylhexyl group; alkenyl group such as vinyl group and allyl group; alkynyl group such as ethynyl group and propargyl group; cyano group; hydroxyl group; nitro group; carboxyl group; methoxy group, ethoxy group, iso Alkoxy groups such as propoxy, tert-butoxy, n-octyloxy, and 2-methoxyethoxy; acyloxy groups such as formyloxy, acetyloxy, pivaloyl
- R 3 represents a hydrogen atom, a halogen atom, an alkyl group (preferably having 1 to 20 carbon atoms), an alkenyl group (preferably having 3 to 20 carbon atoms), an aryl group (preferably having 6 to 20 carbon atoms), a hetero group.
- Aryl group preferably 4 to 20 carbon atoms
- hydroxyl group carboxyl group, alkoxy group (preferably 1 to 20 carbon atoms), aryloxy group (preferably 6 to 20 carbon atoms), acyl group, acyloxy group, cyano
- R 3 is more preferably a hydrogen atom, a halogen atom, an alkyl group, a cyano group, or an alkoxy group.
- m represents the degree of substitution, and here represents the degree of substitution of R 3 .
- m is an integer of 0-2.
- two R 3 may be the same as or different from each other.
- N in the general formula (A) indicates the degree of polymerization.
- n is an integer of 1 to 10, preferably 1.
- a plurality of Q, L 2 , Wa, Wb, R 3 and m may be the same as or different from each other.
- L 1 and L 2 in formula (A) are each independently a single bond, an alkylene group, an alkenylene group, an alkynylene group, an —O— group, a — (C ⁇ O) — group, or — (C ⁇ O).
- a divalent linking group selected from the group consisting of —O— group, —NR L — group, —S— group, — (O ⁇ S ⁇ O) — group, and — (C ⁇ O) —NR L — group; Or a combination thereof.
- —O— group, — (C ⁇ O) —O— group, —O— (C ⁇ O) — group, — (C ⁇ O) —NH group—, and —NH— (C ⁇ O) -Group is preferred.
- L 1 is a single bond that R 1 and Q are directly connected
- L 2 is a single bond that R 2 and Q are directly connected.
- R L in L 1 and L 2 represents a substituent.
- the substituent shown below is mentioned, for example.
- alkyl group such as methyl group, ethyl group, n-propyl group, isopropyl group, tert-butyl group, n-octyl group, and 2-ethylhexyl group
- cyclohexyl group, cyclopentyl group, and 4 -Cycloalkyl groups such as n-dodecylcyclohexyl group
- aryl groups such as phenyl group, p-tolyl group, and naphthyl group
- a cyano group such as a pyridyl group
- the compound represented by the general formula (A) is preferably a compound represented by the general formula (B).
- Wa, Wb, R 3 , m, L 1 , L 2 , R 1 , and R 2 in the general formula (B) are Wa, Wb, R 3 , m, L 1 , L 2 , in the general formula (A), R 1 and R 2 are defined similarly.
- the orientation degree Sa of the additive represented by the general formula (A) in order to set the orientation degree Sa of the additive represented by the general formula (A) within the above range, it is represented by R 1 -L 1- (QL 2 ) n -R 2 . It is preferable that the partial structure to be formed has high linearity and rigidity. Therefore, it is preferable that the compound represented by general formula (B) is a compound represented by general formula (1B).
- Wa of the general formula (1B), Wb, R 3 , m, L 1, L 2, R 1, and R 2 Wa in formula (A), Wb, R 3 , m, L 1, L 2, R 1 and R 2 are defined similarly.
- the additive represented by the general formula (A) is specifically exemplified below, but the additive that can be used in the present embodiment is not limited by the following specific examples (Compound Nos. 1 to 64). .
- L 1 , L 2 , R 1 , and R 2 may be expressed as L 1 , L 2 , R 1 , and R 2 .
- the compound described above as a specific example of the additive represented by the general formula (A) may be any isomer unless otherwise specified, when geometric isomers (trans isomer and cis isomer) exist. It is not limited. In addition, the trans isomer is preferable to the cis isomer in terms of high retardation development.
- the additive represented by the general formula (A) can be synthesized by a known method. Specifically, for example, it can be synthesized with reference to the method described in JP-A-2008-107767.
- the content of the additive represented by the general formula (A) is appropriately set to such an extent that the required wavelength dispersion adjusting ability and retardation can be imparted. Specifically, the content is preferably 1 to 10% by mass, more preferably 2 to 8% by mass with respect to the cellulose acylate resin.
- the content is preferably 1 to 10% by mass, more preferably 2 to 8% by mass with respect to the cellulose acylate resin.
- there is too much content of the additive represented by general formula (A) there exists a tendency which tends to produce a bleed-out.
- content of the additive represented by general formula (A) is in the said range, sufficient wavelength dispersibility and high phase difference expression property can be provided to retardation film.
- the retardation film according to the present embodiment may further contain various plasticizers as necessary.
- the plasticizer can contribute to the degree of orientation Spol of the cellulose acylate resin.
- you may contain a plasticizer in order to improve the fluidity
- a sugar ester compound will be described as a plasticizer.
- sugar ester compound is a compound having 1 to 12 furanose structures or pyranose structures, in which all or part of the hydroxyl groups in the compound are esterified.
- sugar ester compounds include sucrose ester compounds represented by the following general formula (3).
- R 1 to R 8 in the general formula (3) represent a substituted or unsubstituted alkylcarbonyl group or a substituted or unsubstituted arylcarbonyl group.
- R 1 to R 8 may be the same as or different from each other.
- the substituted or unsubstituted alkylcarbonyl group is preferably a substituted or unsubstituted alkylcarbonyl group having 2 or more carbon atoms.
- Examples of the substituted or unsubstituted alkylcarbonyl group include a methylcarbonyl group (acetyl group).
- the substituted or unsubstituted arylcarbonyl group is preferably a substituted or unsubstituted arylcarbonyl group having 7 or more carbon atoms.
- the arylcarbonyl group include a phenylcarbonyl group.
- the substituent that the aryl group has include an alkyl group such as a methyl group and an alkoxyl group such as a methoxy group.
- the average ester substitution degree of the sucrose ester compound is preferably 3.0 to 7.5. If the average ester substitution degree is less than 3.0 or more than 7.5, it is difficult to obtain sufficient compatibility with the cellulose ester.
- sucrose ester compound represented by the general formula (3) include the following.
- R in the table represents R 1 to R 8 in the general formula (3).
- sugar ester compound examples include compounds described in JP-A Nos. 62-42996 and 10-237084.
- the content of the sugar ester compound is preferably 0.5 to 35% by mass, more preferably 5 to 30% by mass with respect to the cellulose acylate resin.
- plasticizers other than sugar ester compounds will be described.
- plasticizers include polyester plasticizers, polyhydric alcohol ester plasticizers, polycarboxylic acid ester plasticizers (including phthalate ester plasticizers), glycolate plasticizers and ester plasticizers.
- Plasticizers including citrate ester plasticizers, fatty acid ester plasticizers, phosphate ester plasticizers, trimellitic ester plasticizers, etc. are included. These may be used alone or in combination of two or more.
- the polyester plasticizer is a compound obtained by reacting a monovalent to tetravalent carboxylic acid and a monovalent to hexavalent alcohol, preferably a compound obtained by reacting a divalent carboxylic acid and a glycol. It is.
- divalent carboxylic acids examples include glutaric acid, itaconic acid, adipic acid, phthalic acid, azelaic acid, sebacic acid and the like.
- a compound using adipic acid, phthalic acid or the like as a divalent carboxylic acid can impart good plasticity.
- glycols examples include ethylene glycol, propylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 1,6-hexamethylene glycol, neopentylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol and the like. included.
- One type of divalent carboxylic acid and glycol may be used, respectively, or two or more types may be used in combination.
- the polyester plasticizer may be any of ester, oligoester and polyester.
- the molecular weight of the polyester plasticizer is preferably in the range of 100 to 10,000, and more preferably in the range of 600 to 3,000 because the effect of imparting plasticity is great.
- the viscosity of the polyester plasticizer depends on the molecular structure and molecular weight, but in the case of an adipic acid plasticizer, it has a high compatibility with a thermoplastic resin and a high effect of imparting plasticity. -It is preferable that it is the range of s (25 degreeC).
- One type of polyester plasticizer may be used, or two or more types may be used in combination.
- the polyhydric alcohol ester plasticizer is an ester compound (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 compound preferably has an aromatic ring or a cycloalkyl ring in the molecule.
- aliphatic polyhydric alcohol examples include ethylene glycol, propylene glycol, trimethylolpropane, pentaerythritol and the like.
- the monocarboxylic acid can be an aliphatic monocarboxylic acid, an alicyclic monocarboxylic acid, an aromatic monocarboxylic acid, or the like.
- One kind of monocarboxylic acid may be used, or a mixture of two or more kinds may be used.
- 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.
- Examples of such aliphatic monocarboxylic acids include acetic acid, propionic acid, butyric acid, valeric acid, and the like, and acetic acid may be preferable in order to enhance compatibility with the cellulose ester.
- 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; one having 1 to 3 alkyl groups or alkoxy groups (for example, methoxy group or ethoxy group) introduced into the benzene ring of benzoic acid (for example, toluic acid); benzene ring 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.
- the molecular weight of the polyhydric alcohol ester plasticizer is not particularly limited, but is preferably 300 to 1500, and more preferably 350 to 750. In order to make it difficult to volatilize, a higher molecular weight is preferable; in order to improve moisture permeability and compatibility with cellulose ester, a lower molecular weight is preferable.
- polyhydric alcohol ester plasticizer examples include trimethylolpropane triacetate, pentaerythritol tetraacetate, ester compound (A) represented by the general formula (I) described in JP-A-2008-88292, and the like. .
- the polyvalent carboxylic acid ester plasticizer is an ester compound 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. For this, oxypolycarboxylic acids are preferred.
- the alcohol compound examples include an aliphatic saturated alcohol compound having a straight chain or a side chain, an aliphatic unsaturated alcohol compound having a straight chain or a 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 include phenol, paracresol, dimethylphenol, benzyl alcohol, cinnamyl alcohol and the like.
- the alcohol compound may be one kind or a mixture of two or more kinds.
- the molecular weight of the polyvalent carboxylic acid ester plasticizer is not particularly limited, but is preferably 300 to 1000, and more preferably 350 to 750.
- the molecular weight of the polyvalent carboxylic acid ester plasticizer is preferably larger from the viewpoint of suppressing bleed-out; it is preferably smaller from the viewpoint of moisture permeability and compatibility with the cellulose ester.
- the acid value of the polyvalent carboxylic acid ester plasticizer is preferably 1 mgKOH / g or less, more preferably 0.2 mgKOH / g or less.
- the acid value means the number of milligrams of potassium hydroxide necessary for neutralizing the acid (carboxyl group present in the sample) contained in 1 g of the sample.
- the acid value is measured according to JIS K0070.
- polycarboxylic acid ester plasticizer examples include an ester compound (B) represented by the general formula (II) described in JP-A-2008-88292.
- the polycarboxylic acid ester plasticizer may be a phthalate ester plasticizer.
- the phthalate ester plasticizer 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 plasticizers 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, etc. .
- the ester plasticizer includes a fatty acid ester plasticizer, a citrate ester plasticizer, a phosphate ester plasticizer, a trimellitic acid plasticizer, and the like.
- fatty acid ester plasticizers include butyl oleate, methylacetyl ricinoleate, and dibutyl sebacate.
- citrate plasticizer include acetyltrimethyl citrate, acetyltriethyl citrate, and acetyltributyl citrate.
- phosphate ester plasticizer include triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, diphenyl biphenyl phosphate, trioctyl phosphate, tributyl phosphate, and the like.
- trimellitic acid plasticizers include octyl trimellitic acid, n-octyl trimellitic acid, isodecyl trimellitic acid, and isononyl trimellitic acid.
- the content of such a plasticizer is preferably 0.5 to 30% by mass with respect to the thermoplastic resin (cellulose acylate resin). If the plasticizer content exceeds 30% by mass, the film tends to bleed out.
- the retardation film according to the present embodiment may further contain an antioxidant, an antistatic agent, a flame retardant and the like for thermal decomposition during molding and coloring by heat.
- Phosphorus flame retardants include red phosphorus, triaryl phosphate ester, diaryl phosphate ester, monoaryl phosphate ester, aryl phosphonate compound, aryl phosphine oxide compound, condensed aryl phosphate ester, halogenated alkyl phosphate ester, One or more kinds selected from halogen condensed phosphoric acid esters, halogen-containing condensed phosphonic acid esters, halogen-containing phosphorous acid esters and the like can be mentioned.
- triphenyl phosphate 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, phenylphosphonic acid, tris ( ⁇ -chloroethyl) phosphate, tris (dichloropropyl) phosphate. , Tris (tribromoneopentyl) phosphate, and the like.
- the retardation film according to this embodiment may further contain an ultraviolet absorber.
- the ultraviolet absorber may be benzotriazole, 2-hydroxybenzophenone, salicylic acid phenyl ester, or the like.
- an ultraviolet absorber having a molecular weight of 400 or more is difficult to volatilize at a high boiling point and hardly scatters at the time of high-temperature molding. Therefore, even if the addition amount is relatively small, weather resistance can be imparted to the resulting film. it can.
- ultraviolet absorbers having a molecular weight of 400 or more examples include 2- [2-hydroxy-3,5-bis ( ⁇ , ⁇ -dimethylbenzyl) phenyl] -2-benzotriazole, 2,2-methylenebis [4- Benzotriazoles such as (1,1,3,3-tetrabutyl) -6- (2H-benzotriazol-2-yl) phenol]; Hindered amines such as bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate; 2- (3,5-di-t-butyl-4-hydroxybenzyl) -2-n-butylmalonate bis (1,2,2,6,6-pentamethyl-4-piperidyl), 1- [2- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy] ethyl] -4- [3- (3,5-di
- the retardation film according to the present embodiment may contain fine particles.
- the fine particles are made of an inorganic compound or an organic compound.
- inorganic compounds include silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate And calcium phosphate.
- organic compounds include polytetrafluoroethylene, cellulose acetate, polystyrene, polymethyl methacrylate, polypropyl methacrylate, polymethyl acrylate, polyethylene carbonate, acrylic styrene resin, silicone resin, polycarbonate resin, benzoguanamine resin, melamine Resin, polyolefin powder, polyester resin, polyamide resin, polyimide resin, polyfluorinated ethylene resin, pulverized classification of organic polymer compounds such as starch, polymer compound synthesized by suspension polymerization method, spray It may be a polymer compound or the like made spherical by a dry method or a dispersion method.
- the fine particles can be composed of a compound containing silicon (preferably silicon dioxide) from the viewpoint that the haze of the obtained film can be kept low.
- Examples of the fine particles of silicon dioxide include Aerosil R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, TT600 (manufactured by Nippon Aerosil Co., Ltd.) and the like.
- zirconium oxide fine particles examples include Aerosil R976 and R811 (manufactured by Nippon Aerosil Co., Ltd.).
- the polymer fine particle resin examples include a silicone resin, a fluororesin, and a (meth) acrylic resin, preferably a silicone resin, and more preferably a silicone resin having a three-dimensional network structure.
- silicone resins include Tospearl 103, 105, 108, 120, 145, 3120, and 240 (manufactured by Toshiba Silicone Co., Ltd.).
- Aerosil 200V and Aerosil R972V are particularly preferable because they can improve the slipperiness of the film surface while keeping the haze of the retardation film low.
- the average primary particle diameter of the fine particles is preferably 5 to 400 nm, more preferably 10 to 300 nm.
- the fine particles may mainly form secondary aggregates having a particle size of 0.05 to 0.3 ⁇ m. If the average particle size of the fine particles is 100 to 400 nm, they can exist as primary particles without agglomeration.
- the content of the fine particles is preferably 0.01 to 1% by mass and more preferably 0.05 to 0.5% by mass with respect to the thermoplastic resin.
- the retardation film according to the present embodiment may further contain a dispersant in order to improve the dispersibility of the fine particles.
- the dispersant is one or more selected from amine-based dispersants and carboxyl group-containing polymer dispersants.
- the amine dispersant is preferably an alkylamine or an amine salt of polycarboxylic acid.
- Specific examples thereof include polyester acid, polyether ester acid, fatty acid, fatty acid amide, polycarboxylic acid, alkylene oxide, and polyalkylene oxide.
- Examples of amine salts include amidoamine salts, aliphatic amine salts, aromatic amine salts, alkanolamine salts, polyvalent amine salts and the like.
- amine dispersant examples include polyoxyethylene fatty acid amide, polyoxyethylene alkylamine, tripropylamine, diethylaminoethylamine, dimethylaminopropylamine, diethylaminopropylamine and the like.
- examples of commercially available products include Solspers series (manufactured by Lubrizol), Ajisper series (manufactured by Ajinomoto Co.), BYK series (manufactured by Big Chemie), EFKA series (manufactured by EFKA), and the like.
- the carboxyl group-containing polymer dispersant is preferably a polycarboxylic acid or a salt thereof, and may be, for example, polycarboxylic acid, ammonium polycarboxylate, sodium polycarboxylate, or the like.
- Specific examples of the carboxyl group-containing polymer dispersant include polyacrylic acid, ammonium polyacrylate, sodium polyacrylate, ammonium polyacrylate copolymer, polymaleic acid, ammonium polymaleate, and sodium polymaleate.
- the amine-based dispersant and the carboxyl group-containing polymer dispersant may be used after being dissolved in a solvent component, or may be commercially available.
- the content of the dispersant is preferably 0.2% by mass or more based on the fine particles, although it depends on the type of the dispersant. When the content of the dispersant is less than 0.2% by mass with respect to the fine particles, the dispersibility of the fine particles cannot be sufficiently improved.
- the retardation film according to the present embodiment further contains a surfactant or the like
- the adsorption of the dispersant to the surface of the fine particles is less likely to occur than the surfactant, and the fine particles may be easily re-aggregated.
- the dispersant is expensive, its content is preferably as small as possible.
- the content of the dispersant is too small, poor wettability of fine particles and a decrease in dispersion stability are likely to occur. Therefore, when the optical film of the present invention further contains a surfactant or the like, the content of the dispersant can be about 0.05 to 10 parts by weight with respect to 10 parts by weight of the fine particles.
- the thickness of the retardation film is preferably 80 ⁇ m or less, more preferably 60 ⁇ m or less, and further preferably 40 ⁇ m or less.
- the thickness of the retardation film is preferably 10 ⁇ m or more, more preferably 20 ⁇ m or more, in order to develop a certain level of film strength or retardation. When the thickness of the retardation film is within these ranges, it is preferable from the viewpoint of thinning the display device and productivity.
- the orientation degree Spol of the cellulose acylate resin and the orientation degree Sa of the additive are preferably within the above range.
- the degree of orientation Sa of the additive is preferably in the above range.
- the haze (total haze) of the retardation film is preferably less than 1%, more preferably 0.5% or less, and even more preferably 0.2% or less. When the haze is within such a range, the transparency of the film is good and the film can sufficiently function as a retardation film.
- the haze can be adjusted by the total number of carbon atoms in the acyl group per glucose unit of the cellulose acylate resin contained in the retardation film. Specifically, it is preferable from the viewpoint of haze to use a cellulose acylate resin in which the total number of carbon atoms in the acyl group per glucose unit is 6.5 or less. Moreover, it can adjust also with the additive contained in retardation film. It is preferable from the viewpoint of haze to use an additive represented by the general formula (A) and having an SP value of 16 to 23 determined by the bicerano method.
- the haze (total haze) of the retardation film can be measured with a haze meter (NDH-2000 manufactured by Nippon Denshoku Co., Ltd.) in accordance with JIS K-7136.
- the light source of the haze meter may be a 5V9W halogen sphere, and the light receiving part may be a silicon photocell (with a relative visibility filter).
- the haze can be measured under conditions of 23 ° C. and 55% RH.
- the visible light transmittance of the retardation film is preferably 90% or more, and more preferably 93% or more.
- the ⁇ / 4 retardation film according to this embodiment is used as an optical film for an image display device such as an organic EL display device or a liquid crystal display device; specifically, a polarizing plate protective film, an optical compensation film, an antireflection film, or the like. It is done.
- the ⁇ / 4 retardation film according to the present embodiment can be preferably used as a circularly polarizing plate by being bonded to a polarizer (linear polarizing film).
- the retardation film according to this embodiment can be formed according to a known method. Hereinafter, typical solution casting methods and melt casting methods will be described.
- the retardation film according to this embodiment can be produced by a solution casting method.
- a step of preparing a dope by heating and dissolving cellulose acylate resin and additives in an organic solvent a step of casting the prepared dope on a belt-shaped or drum-shaped metal support, casting A step of drying the dope as a web, a step of peeling from the metal support, a step of stretching or shrinking the peeled web, a step of drying, a step of winding up the finished film, and the like.
- the cellulose acylate resin in the dope preferably has a higher concentration because the drying load after casting on the metal support can be reduced, but if the concentration of the cellulose acylate resin is too high, The load increases and the filtration accuracy deteriorates.
- the concentration at which these are compatible is preferably in the range of 10 to 35% by mass, more preferably in the range of 15 to 25% by mass.
- dope contains the component and solvent which comprise retardation film.
- the solvent include a solvent that can dissolve the cellulose acylate resin.
- organic solvents such as chlorinated organic solvents and non-chlorinated organic solvents.
- chlorinated organic solvent examples include methylene chloride (methylene chloride).
- Non-chlorine organic solvents include, for example, methyl acetate, ethyl acetate, amyl acetate, acetone, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, cyclohexanone, ethyl formate, 2,2,2-trifluoro Ethanol, 2,2,3,3-hexafluoro-1-propanol, 1,3-difluoro-2-propanol, 1,1,1,3,3,3-hexafluoro-2-methyl-2-propanol, Examples include 1,1,1,3,3,3-hexafluoro-2-propanol, 2,2,3,3,3-pentafluoro-1-propanol, and nitroethane. From the viewpoint of recent environmental problems, non-chlorine organic solvents are preferably used.
- the insoluble matter is reduced by a known dissolution method such as a dissolution method at normal temperature, a high-temperature dissolution method, a cooling dissolution method, and a high-pressure dissolution method. It is preferable.
- a known dissolution method such as a dissolution method at normal temperature, a high-temperature dissolution method, a cooling dissolution method, and a high-pressure dissolution method. It is preferable.
- methylene chloride can be used, but methyl acetate, ethyl acetate, and acetone are preferably used, and among them, methyl acetate is particularly preferable.
- an organic solvent having good solubility in the cellulose acylate resin is referred to as a good solvent, and has a main effect on dissolution, and an organic solvent used in a large amount among them is mainly (organic). Solvent or main (organic) solvent.
- the dope used for forming the retardation film according to this embodiment preferably contains an alcohol having 1 to 4 carbon atoms in the range of 1 to 40% by mass in addition to the organic solvent.
- These alcohols after casting the dope on a metal support, start to evaporate the organic solvent, and when the relative proportion of the alcohol component increases, the dope film (web) gels, making the web strong and supporting the metal It can act as a gelling solvent that facilitates peeling from the body, and when the proportion of these alcohols is low, it also has a role of promoting dissolution of the cellulose acylate resin of a non-chlorine organic solvent.
- Examples of the alcohol having 1 to 4 carbon atoms include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, and tert-butanol. Of these, it is preferable to use ethanol from the viewpoints of excellent dope stability, relatively low boiling point, and good drying properties. These alcohols are categorized as poor solvents because they are not soluble in cellulose acylate resin alone.
- the metal support used preferably has a mirror-finished surface, and a stainless steel belt or a drum whose surface is plated with a casting is preferably used.
- the cast width is preferably in the range of 1 to 4 m.
- the surface temperature of the metal support in the casting step is appropriately selected and set within a range of ⁇ 50 ° C. to a temperature at which the solvent boils and does not foam. A higher temperature is preferable because the web can be dried faster, but if it is too high, the web may foam and flatness may deteriorate.
- a preferable support temperature is appropriately determined within the range of 0 to 100 ° C. A temperature range of 5 to 30 ° C. is more preferred.
- the web can be 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 warm air or cold air, and a method of bringing hot water into contact with the back side of the metal support.
- the method using hot water is preferable because the heat transfer is performed efficiently, and 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 is a case where wind at a temperature higher than the target temperature is used while preventing foaming. is there.
- the amount of residual solvent when peeling the web from the metal support is preferably set within the range of 10 to 150% by mass, more preferably 20%. It is in the range of ⁇ 40 mass% or 60 to 130 mass%, more preferably in the range of 20 to 30 mass% or 70 to 120 mass%.
- the residual solvent amount is defined by the following formula.
- Residual solvent amount (% by mass) ⁇ (MN) / N ⁇ ⁇ 100 (Wherein, M is the mass of a sample taken at any time during or after production of the web or film, and N is the mass after heating M at 115 ° C. for 1 hour.)
- the web is peeled off from the metal support and further dried, so that the residual solvent amount is preferably 1.0% by mass or less, more preferably 0 to 0.01% by mass.
- a roller drying method for example, a method in which webs are alternately passed through a number of upper and lower rollers and a method in which a web is dried while being conveyed by a tenter method is employed.
- the ⁇ / 4 retardation film of the present embodiment preferably has an in-plane retardation Ro550 measured at a wavelength of 550 nm of 115 to 160 nm, and such retardation is imparted by stretching the film. obtain.
- the stretching method is not particularly limited, for example, a method in which a circumferential speed difference is provided to a plurality of rollers, and a longitudinal stretching is performed using the roller circumferential speed difference therebetween, and both ends of the web are fixed with clips or pins.
- a method of extending the distance between pins in the traveling direction and extending in the vertical direction, a method of expanding in the horizontal direction and extending in the horizontal direction, or a method of extending the vertical and horizontal directions simultaneously and extending in both the vertical and horizontal directions may be employed alone or in combination. it can. That is, the film may be stretched in the transverse direction, longitudinally, or in both directions with respect to the film forming direction, and when stretched in both directions, simultaneous stretching or sequential stretching may be used. May be. In the case of the so-called tenter method, driving the clip portion by the linear drive method is preferable because smooth stretching can be performed and the risk of breakage and the like can be reduced.
- the film is usually stretched in the width direction (TD direction) and contracted in the transport direction (MD direction), but when contracted, it is easy to match the main chain direction when transported in an oblique direction. In addition, the phase difference effect is even greater.
- the shrinkage rate can be determined by the transport angle.
- FIG. 1 is a schematic diagram for explaining the shrinkage ratio in oblique stretching.
- reference numeral 111 is a stretching direction (TD direction)
- reference numeral 113 is a transport direction (MD direction)
- reference numeral 114 indicates a slow axis.
- the ⁇ / 4 retardation film according to the present embodiment has an orientation angle of 45 ° ⁇ 2 ° with respect to the transport direction. Bonding with can be performed, which is preferable.
- the orientation angle of the film can be freely set, and the orientation axis of the film can be set to the left and right with high precision across the film width direction.
- a film stretching apparatus that can be oriented and can control the film thickness and retardation with high accuracy is preferable.
- FIG. 2 is a schematic view showing an example of a rail pattern of an oblique stretching apparatus applicable to the production of a ⁇ / 4 retardation film according to this embodiment.
- the figure shown here is an example, Comprising: The extending
- the feeding direction D1 of the long film original is different from the winding direction D2 of the stretched film after stretching, and forms a feeding angle ⁇ i. is doing.
- the feeding angle ⁇ i can be arbitrarily set to a desired angle in the range of more than 0 ° and less than 90 °.
- the term “long” refers to a film having a length of at least about 5 times the width of the film, preferably a film having a length of 10 times or more.
- the long film original is gripped by the right and left grippers (tenters) at the entrance of the oblique stretching apparatus (position A in the figure), and travels as the grippers travel.
- the left and right gripping tools are the left and right gripping tools Ci and Co at the entrance of the oblique stretching apparatus (position A in the figure) and facing the direction substantially perpendicular to the film traveling direction (feeding direction D1).
- the film travels on the asymmetric rails Ri and Ro, and the film gripped by the tenter is released at the position at the end of stretching (position B in the figure).
- the gripping tools Ci and Co that are opposed to the film feeding direction D1 at the oblique stretching apparatus entrance (the gripping start position by the film gripping tool) A are positions at the end of the film stretching.
- the straight line connecting the grippers Ci and Co is inclined by an angle ⁇ L with respect to a direction substantially perpendicular to the film winding direction D2.
- the original film is obliquely stretched so that the orientation angle is ⁇ L, and a retardation film is obtained.
- substantially vertical indicates that the angle is in a range of 90 ⁇ 1 °.
- This stretching device is a device that heats the film fabric to an arbitrary temperature at which stretching is possible and stretches it obliquely.
- This stretching apparatus includes a heating zone, a pair of rails on the left and right on which a gripping tool for transporting the film travels, and a number of gripping tools that travel on the rails. Both ends of the film sequentially supplied to the inlet of the stretching apparatus are gripped by a gripping tool, the film is guided into the heating zone, and the film is released from the gripping tool at the outlet of the stretching apparatus. The film released from the gripping tool is wound around the core.
- Each of the pair of rails has an endless continuous track, and the gripping tool which has released the grip of the film at the outlet portion of the stretching apparatus travels outside and is sequentially returned to the inlet portion.
- the rail pattern of the stretching device has an asymmetric shape on the left and right, and the rail pattern can be adjusted manually or automatically depending on the orientation angle, stretch ratio, etc. given to the long stretched film to be manufactured. It has become.
- the position of each rail portion and the rail connecting portion can be freely set, and the rail pattern can be arbitrarily changed (the ⁇ portion in FIG. 2 indicates an example of the connecting portion).
- the gripping tool of the stretching apparatus travels at a constant speed with a constant distance from the front and rear gripping tools.
- the traveling speed of the gripping tool can be selected as appropriate, but is usually 1 to 100 m / min.
- the difference in travel speed between the pair of left and right grippers is usually 1% or less, preferably 0.5% or less, more preferably 0.1% or less of the travel speed. This is because if there is a difference in the traveling speed between the left and right sides of the film at the exit of the stretching process, wrinkles and shifts will occur at the exit of the stretching process, so the speed difference between the left and right gripping tools is required to be substantially the same speed. Because. In general stretching equipment, etc., there is a speed unevenness that occurs in the order of seconds or less depending on the period of the sprocket teeth driving the chain, the frequency of the drive motor, etc. This does not correspond to the speed difference described in the embodiment.
- a large bending rate is often required for the rail that regulates the locus of the gripping tool, particularly in a portion where the film is transported obliquely.
- the trajectory of the gripping tool draws a curve at the bent portion.
- the long film original fabric is gripped by the right and left grippers sequentially at the entrance of the oblique stretching apparatus (position A in the figure), and travels as the grippers travel.
- the left and right gripping tools facing the direction substantially perpendicular to the film traveling direction (feeding direction D1) at the entrance of the oblique stretching apparatus (position A in the figure) run on a rail that is asymmetrical to the preheating zone. Through a heating zone having a stretching zone and a heat setting zone.
- the preheating zone refers to a section where the distance between the gripping tools gripping both ends is kept constant at the heating zone entrance.
- the stretching zone refers to the interval until the gap between the gripping tools that grips both ends starts to reach a predetermined interval.
- the oblique stretching as described above is performed, but the stretching may be performed in the longitudinal direction or the transverse direction before and after the oblique stretching as necessary.
- there is contraction in the MD direction (fast axis direction) which is a direction perpendicular to the slow axis during bending.
- an optical adjustment agent for example, the general formula (described above) that is deviated from the main chain of the cellulose acylate that is the matrix resin by performing a shrinkage treatment following the stretching treatment.
- the orientation of the compound represented by A) is contracted in the direction perpendicular to the stretching direction (the fast axis direction) to rotate the orientation state of the optical adjusting agent, and the main axis of the optical adjusting agent is a matrix resin. It can be matched with the main chain of cellulose acylate.
- the refractive index ny 280 in the fast axis direction in the ultraviolet region 280 nm can be increased, and the slope of the ny forward wavelength dispersion in the visible light region can be made steep.
- the heat setting zone refers to the section in which the gripping tools at both ends run parallel to each other during the period when the spacing between the gripping tools after the stretching zone becomes constant again. You may pass through the area (cooling zone) by which the temperature in a zone is set to below the glass transition temperature Tg of the thermoplastic resin which comprises a film, after passing through a heat setting zone. At this time, in consideration of shrinkage of the film due to cooling, a rail pattern that narrows the gap between the opposing grippers in advance may be used.
- the temperature of each zone is the glass transition temperature Tg of the thermoplastic resin
- the temperature of the preheating zone is within the range of Tg to Tg + 30 ° C
- the temperature of the stretching zone is within the range of Tg to Tg + 30 ° C
- the temperature of the cooling zone is It is preferably set within the range of Tg-30 ° C. to Tg.
- a temperature difference in the width direction may be applied in the stretching zone.
- a method of adjusting the opening degree of the nozzle for sending warm air into the temperature-controlled room so as to make a difference in the width direction, or controlling the heating by arranging the heaters in the width direction is known. Can be used.
- the lengths of the preheating zone, stretching zone, shrinkage zone and cooling zone can be appropriately selected.
- the length of the preheating zone is usually in the range of 100 to 150% with respect to the length of the stretching zone, and the length of the fixed zone Is usually in the range of 50 to 100%.
- the draw ratio (W / W0) in the drawing step is preferably in the range of 1.3 to 3.0, more preferably in the range of 1.5 to 2.8. When the draw ratio is within this range, the thickness unevenness in the width direction can be reduced. In the stretching zone of the oblique stretching apparatus, the thickness direction unevenness can be further improved by making a difference in the stretching temperature in the width direction.
- W0 represents the width of the film before stretching
- W represents the width of the film after stretching.
- the oblique stretching method applicable in this embodiment includes the stretching methods shown in FIGS. 3 (a) to 3 (c) and FIGS. 4 (a) and 4 (b). Can be mentioned.
- FIG. 3 is a schematic view showing a method for producing a retardation film according to an embodiment of the present invention (an example in which the film is drawn from a long film roll and then obliquely stretched), and is a length once wound into a roll shape. The pattern which draws out the original film and draws it diagonally is shown.
- FIG. 4 is a schematic diagram illustrating a method for producing a retardation film according to an embodiment of the present invention (an example in which a long film original is continuously stretched obliquely without winding up). The pattern which performs a diagonal stretch process continuously, without winding up is shown.
- reference numeral 15 is an oblique stretching apparatus
- reference numeral 16 is a film feeding apparatus
- reference numeral 17 is a conveying direction changing apparatus
- reference numeral 18 is a winding apparatus
- reference numeral 19 is a film forming apparatus. Yes.
- reference numerals indicating the same components may be omitted.
- the film feeding device 16 is slidable and swivelable or slidable so that the film can be sent out at a predetermined angle with respect to the oblique stretching device inlet. It is preferable to be able to send FIGS. 3A to 3C show patterns in which the arrangement of the film feeding device 16 and the conveyance direction changing device 17 is changed. FIGS. 4A and 4B show a pattern in which the film formed by the film forming apparatus 19 is directly fed to a stretching apparatus.
- the width of the entire manufacturing apparatus can be further reduced, and the film feeding position and angle can be finely controlled.
- the film feeding device 16 and the transport direction changing device 17 it is possible to effectively prevent the left and right clips from being caught in the film.
- the winding device 18 is arranged so that the film can be pulled at a predetermined angle with respect to the outlet of the oblique stretching device, so that the film take-up position and angle can be finely controlled, and variations in film thickness and optical value can be achieved. It becomes possible to obtain a long stretched film having a small diameter. Therefore, the generation of wrinkles in the film can be effectively prevented, and the winding property of the film is improved, so that the film can be wound up in a long length.
- the take-up tension T (N / m) of the stretched film can be adjusted within a range of 100 N / m ⁇ T ⁇ 300 N / m, preferably 150 N / m ⁇ T ⁇ 250 N / m. preferable.
- the above-mentioned ⁇ / 4 retardation film may be formed by a melt film forming method.
- the melt film-forming method is a molding method in which a composition containing an additive such as a resin and a plasticizer is heated and melted to a temperature exhibiting fluidity, and then a melt containing a fluid thermoplastic resin is cast. .
- the molding method for heating and melting can be classified into, for example, a melt extrusion molding method, a press molding method, an inflation method, an injection molding method, a blow molding method, and a stretch molding method.
- the melt extrusion method is preferable from the viewpoint of mechanical strength and surface accuracy.
- the plurality of raw materials used in the melt extrusion method are usually preferably kneaded in advance and pelletized.
- Pelletization can be performed by a known method, for example, dry cellulose acylate, plasticizer, and other additives are fed to an extruder with a feeder, and kneaded using a single or twin screw extruder, It can be obtained by extruding into a strand form from a die, cooling with water or air, and cutting.
- the additives may be mixed before being supplied to the extruder, or may be supplied by individual feeders.
- a small amount of additives such as fine particles and antioxidants are preferably mixed in advance in order to mix uniformly.
- the extruder used for pelletization preferably has a method of processing at as low a temperature as possible so that pelletization is possible so that the shearing force is suppressed and the resin does not deteriorate (molecular weight reduction, coloring, gel formation, etc.).
- a twin screw extruder it is preferable to rotate in the same direction using a deep groove type screw. From the uniformity of kneading, the meshing type is preferable.
- Film formation is performed using the pellets obtained as described above.
- the raw material powder can be put into a feeder as it is, supplied to an extruder, heated and melted, and then directly formed into a film without being pelletized.
- the melting temperature is in the range of 200 to 300 ° C.
- T A film is cast from the die, the film is nipped by a cooling roller and an elastic touch roller, and solidified on the cooling roller.
- the extrusion flow rate is preferably carried out stably by introducing a gear pump.
- a stainless fiber sintered filter is preferably used as a filter used for removing foreign substances.
- a stainless steel fiber sintered filter is a product in which a stainless steel fiber body is intricately intertwined and compressed, and the contact points are sintered and integrated. The density is changed according to the thickness of the fiber and the amount of compression, and filtration is performed. The accuracy can be adjusted.
- Additives such as plasticizers and fine particles may be mixed with the resin in advance, or may be kneaded in the middle of the extruder. In order to add uniformly, it is preferable to use a mixing apparatus such as a static mixer.
- the film temperature on the touch roller side when the film is nipped between the cooling roller and the elastic touch roller is preferably in the range of Tg to Tg + 110 ° C. of the film.
- a known elastic touch roller can be used as the elastic touch roller having an elastic surface used for such a purpose.
- the elastic touch roller is also called a pinching rotary body, and a commercially available one can also be used.
- the film obtained as described above can be subjected to a stretching and shrinking treatment by a stretching operation after passing through a step of contacting a cooling roller.
- a known roller stretching device or oblique stretching device as described above can be preferably used as a method of stretching and shrinking.
- the stretching temperature is usually preferably in the temperature range of Tg to Tg + 60 ° C. of the resin constituting the film.
- the end Before winding, the end may be slit and cut to the product width, and knurled (embossed) may be applied to both ends to prevent sticking or scratching during winding.
- the knurling method can process a metal ring having an uneven pattern on its side surface by heating or pressing.
- grip part of the clip of both ends of a film is cut out and reused.
- the above-described ⁇ / 4 retardation film can be formed into a circularly polarizing plate by laminating so that the angle between the slow axis and the transmission axis of the polarizer described later is substantially 45 °.
- substantially 45 ° means within a range of 40 to 50 °.
- the angle between the in-plane slow axis of the ⁇ / 4 retardation film and the transmission axis of the polarizer is preferably in the range of 41 to 49 °, and in the range of 42 to 48 °. Is more preferably within a range of 43 to 47 °, and particularly preferably within a range of 44 to 46 °.
- the circularly polarizing plate (long circular polarizing plate) according to this embodiment is a long roll having a long protective film, a long polarizer and a long ⁇ / 4 retardation film in this order. It is made by cutting. Since the long circularly polarizing plate according to the present embodiment is produced using the above-described ⁇ / 4 retardation film, it is applied to an organic EL display or the like to be described later, so that the organic EL can be used in a wide range of visible light wavelengths. An effect of shielding the specular reflection of the metal electrode of the element can be exhibited. As a result, reflection during observation can be prevented and black expression can be improved.
- the long circularly polarizing plate has an ultraviolet absorbing function.
- the protective film on the viewing side has an ultraviolet absorbing function from the viewpoint that both the polarizer and the organic EL element can exhibit a protective effect against ultraviolet rays.
- the ⁇ / 4 retardation film on the light emitter side also has an ultraviolet absorbing function, when used in an organic EL display described later, deterioration of the organic EL element can be further suppressed.
- the long circularly polarizing plate according to the present embodiment has the ⁇ / 4 phase difference adjusted so that the angle of the slow axis (that is, the orientation angle) is “substantially 45 °” with respect to the long direction.
- the film By using a film, it is possible to form an adhesive layer and bond the polarizing film and the ⁇ / 4 retardation film plate with a consistent production line. Specifically, after finishing the step of producing the polarizing film by stretching, the step of bonding the polarizing film and the ⁇ / 4 retardation film can be incorporated during or after the subsequent drying step, Each can be continuously supplied, and can be connected in a production line that is consistent with the next process by winding in a roll state after bonding.
- a protective film when bonding a polarizing film and (lambda) / 4 phase difference film, a protective film can also be simultaneously supplied in a roll state and can also be bonded continuously. From the viewpoint of performance and production efficiency, it is preferable to simultaneously bond a ⁇ / 4 retardation film and a protective film to the polarizing film. That is, after finishing the step of producing the polarizing film by stretching, after the subsequent drying step or after the drying step, the protective film and the ⁇ / 4 retardation film are bonded to both sides with an adhesive, It is also possible to obtain a rolled circularly polarizing plate.
- the polarizer is preferably sandwiched between the ⁇ / 4 retardation film and the protective film, and a cured layer is preferably laminated on the viewing side of the protective film.
- the image display apparatus for example, an organic EL display (organic EL image display apparatus) is manufactured using the long circularly polarizing plate. More specifically, the organic EL display according to this embodiment includes a long circularly polarizing plate using the ⁇ / 4 retardation film and an organic EL element.
- the screen size of the organic EL display is not particularly limited, and can be 20 inches or more.
- FIG. 5 is a schematic explanatory diagram of the configuration of the organic EL display of the present embodiment.
- the configuration of the organic EL display of the present embodiment is not limited to that shown in FIG.
- the organic EL element B having 8 can be omitted
- the above-described long circularly polarizing plate C having the polarizer 10 sandwiched between the above-described ⁇ / 4 retardation film 9 and the protective film 11 is provided on the organic EL element B having 8 (can be omitted).
- the protective film 11 is preferably laminated with a cured layer 12.
- the hardened layer 12 not only prevents the surface of the organic EL display from being scratched but also has an effect of preventing warpage due to the long circularly polarizing plate.
- an antireflection layer 13 may be provided on the cured layer.
- the thickness of the organic EL element itself is about 1 ⁇ m.
- the organic light emitting layer is a laminate of various organic thin films, for example, a laminate of a hole injection layer made of a triphenylamine derivative and the like and a light emitting layer made of a fluorescent organic solid such as anthracene, Alternatively, a structure having various combinations such as a laminate of such a light emitting layer and an electron injection layer composed of a perylene derivative or the like, or a laminate of these hole injection layer, light emitting layer, and electron injection layer is known. It has been.
- holes and electrons are injected into the organic light emitting layer by applying a voltage to the transparent electrode and the metal electrode, and the energy generated by recombination of these holes and electrons excites the fluorescent material, It emits light based on the principle that it emits light when the excited fluorescent material returns to the ground state.
- the mechanism of recombination in the middle is the same as that of a general diode, and as can be predicted from this, the current and the emission intensity show strong nonlinearity with rectification with respect to the applied voltage.
- an organic EL display in order to take out light emitted from the organic light emitting layer, at least one of the electrodes needs to be transparent.
- a transparent electrode formed of a transparent conductor such as indium tin oxide (ITO) is used. It is preferably used as an anode.
- ITO indium tin oxide
- metal electrodes such as Mg—Ag and Al—Li are used.
- the long circular polarizing plate having the above-mentioned ⁇ / 4 retardation film can be applied to an organic EL display having a large screen having a screen size of 20 inches or more, that is, a diagonal distance of 50.8 cm or more.
- the organic light emitting layer is formed of a very thin film having a thickness of about 10 nm. Therefore, the organic light emitting layer transmits light almost completely like the transparent electrode. As a result, light that is incident from the surface of the transparent substrate at the time of non-light emission, passes through the transparent electrode and the organic light emitting layer, and is reflected by the metal electrode is again emitted to the surface side of the transparent substrate.
- the display surface of the organic EL display looks like a mirror surface.
- an organic EL display including an organic EL element having a transparent electrode on the surface side of an organic light emitting layer that emits light by applying a voltage and a metal electrode on the back side of the organic light emitting layer, the surface side (viewing side) of the transparent electrode ) And a retardation film can be provided between the transparent electrode and the polarizing plate.
- the retardation film and the polarizing plate have a function of polarizing light incident from the outside and reflected by the metal electrode, there is an effect that the mirror surface of the metal electrode is not visually recognized by the polarization action.
- the retardation film is composed of a ⁇ / 4 retardation film and the angle between the polarization direction of the polarizing plate and the retardation film is adjusted to ⁇ / 4, the mirror surface of the metal electrode can be completely shielded. it can.
- the external light incident on the organic EL display is transmitted only through the linearly polarized light component by the polarizing plate, and this linearly polarized light is generally elliptically polarized by the retardation plate.
- the retardation film is a ⁇ / 4 retardation film.
- the angle formed by the polarization direction of the polarizing plate and the retardation film is ⁇ / 4, circular polarization is obtained.
- This circularly polarized light is transmitted through the transparent substrate, transparent electrode, and organic thin film, reflected by the metal electrode, again transmitted through the organic thin film, transparent electrode, and transparent substrate, and becomes linearly polarized light again by the retardation film. And since this linearly polarized light is orthogonal to the polarization direction of a polarizing plate, it cannot permeate
- One aspect of the present invention is a long retardation film containing a cellulose acylate resin and an additive, wherein the additive is an additive represented by the following general formula (A), and absorbs light.
- the degree of orientation of the cellulose acylate resin, calculated by spectroscopy, is 0.03 or more and 0.15 or less, and the degree of orientation of the additive, calculated by absorption spectroscopy, is greater than 0.15
- An in-plane retardation value of the retardation film at a wavelength of 550 nm is 115 nm or more and 160 nm or less, and an angle formed by an in-plane slow axis of the retardation film and a longitudinal direction of the retardation film is 15 It is a retardation film characterized by being at least 85 ° and at most 85 °.
- Q represents an aromatic hydrocarbon ring, a non-aromatic hydrocarbon ring, an aromatic heterocyclic ring, or a non-aromatic heterocyclic ring
- Wa and Wb represent the Q ring.
- a hydrogen atom or a substituent bonded to the constituent atoms, the atom bonded to Wa and the atom bonded to Wb are adjacent to each other in the ring of Q, and Wa and Wb are different , Wa and Wb may form a ring
- R 1 and R 2 each independently represent a substituent
- R 3 represents a substituent
- the degree of substitution m is 0-2.
- a cellulose acylate film having a sufficiently thin thickness sufficiently suppresses deterioration of brittleness is excellent in transparency, and further, for light in a wide range of visible light wavelengths, A retardation film having an in-plane retardation of about 1 ⁇ 4 of the wavelength can be provided.
- this retardation film is applied to an image display device such as an organic EL display, an image display device capable of displaying a good image in which reflection of external light is sufficiently suppressed can be obtained.
- the cellulose acylate resin preferably has a total carbon number of acyl groups per glucose unit of 6.5 or less.
- the retardation film has an in-plane retardation value Ro (450) at a wavelength of 450 nm, an in-plane retardation value Ro (550) at a wavelength of 550 nm, and an in-plane retardation value at a wavelength of 650 nm.
- Ro (650) preferably satisfies the following formula (1) and the following formula (2).
- the total substitution degree per glucose unit of the acyl group of the cellulose acylate resin is preferably 1.5 or more and 2.5 or less.
- Another aspect of the present invention is a circularly polarizing plate provided with the retardation film.
- Another aspect of the present invention is an image display device including the retardation film.
- cellulose acylate resin those having the substitution degree of acyl groups shown in Table 11 (cellulose acylate resins 1 to 5) were used.
- Additive 1 Compound represented by the following formula (Compound No. 62)
- Additive 2 Compound represented by the following formula (Compound No. 63)
- Additive 3 Compound represented by the following formula (Compound No. 64)
- Additive 4 Compound represented by the following formula (Compound No. 11)
- Plasticizer 1 Compound represented by the following formula Plasticizer 2: Triphenyl phosphate (TPP) Plasticizer 3: Biphenyl diphenyl phosphate (BDP)
- ⁇ Dope composition Methylene chloride 340 parts by weight Ethanol 64 parts by weight Cellulose acylate resin 1 100 parts by weight Additive 1 4 parts by weight Plasticizer 1 5 parts by weight Particulate additive liquid 1 part by weight
- the peeled film is uniaxially stretched at a stretch ratio of 1% only in the width direction (TD direction) using a stretching apparatus while being heated at 180 ° C., and transport tension so as not to shrink in the transport direction (MD direction). Adjusted.
- the residual solvent at the start of stretching was 15% by mass.
- drying was terminated while the drying zone was conveyed through a number of rollers.
- the drying temperature was 130 ° C. and the transport tension was 100 N / m.
- an original resin film wound into a roll was produced.
- Example 2 As the plasticizer, 4 parts by mass of plasticizer 2 and 4 parts by mass of plasticizer 3 were used, and the film thickness was 39 ⁇ m as in Example 1, except that the draw ratio was changed to 1.9 times. / 4 retardation film 2 was produced.
- Example 3 Similar to Example 1, except that cellulose acylate resin 3 was used as the cellulose acylate resin, the stretching temperature was changed to 210 ° C., and the stretching ratio was changed to 1.5 times, ⁇ / 4 having a film thickness of 32 ⁇ m. A retardation film 3 was produced.
- Example 4 As the cellulose acylate resin, the cellulose acylate resin 6 was used, and the film thickness was 22 ⁇ m as in ⁇ / 4, except that the stretching temperature was changed to 200 ° C. and the stretching ratio was changed to 1.4 times. A retardation film 4 was produced.
- Example 5 Similar to Example 1, except that the cellulose acylate resin 5 was used as the cellulose acylate resin, the additive 4 was used as the additive, the stretching temperature was changed to 180 ° C., and the stretching ratio was changed to 1.8 times. A ⁇ / 4 retardation film 5 having a film thickness of 60 ⁇ m was produced.
- Example 6 Similar to Example 1 except that the cellulose acylate resin 4 was used as the cellulose acylate resin, the additive 4 was used as the additive, the stretching temperature was changed to 175 ° C., and the stretching ratio was changed to 1.8 times. A ⁇ / 4 retardation film 6 having a film thickness of 80 ⁇ m was produced.
- Example 1 A ⁇ / 4 retardation film 7 having a film thickness of 65 ⁇ m was produced in the same manner as in Example 1 except that the additive 2 was used as an additive and the stretching temperature was changed to 183 ° C.
- Cellulose acylate resin 2 is used as the cellulose acylate resin
- additive 3 is used as the additive
- plasticizer 2 4 parts by mass and plasticizer 3 4 parts by mass are used as the plasticizer
- the stretching temperature is 195.
- a ⁇ / 4 retardation film 8 having a film thickness of 80 ⁇ m was produced in the same manner as in Example 1 except that the temperature and the draw ratio were changed to 2.1 times.
- Example 6 Similar to Example 1, except that the cellulose acylate resin 3 was used as the cellulose acylate resin, the stretching temperature was changed to 210 ° C., and the stretching ratio was changed to 2.0 times, ⁇ / 4 having a film thickness of 30 ⁇ m. A retardation film 12 was produced.
- the orientation degree Sa of the additive was calculated according to the following formula.
- the created Spol measurement film is installed in the spectrophotometer in which the polarizer is arranged on the light source side in the same manner as when calculating Sa, and the transmission axis of the polarizer and the slow axis direction of the film coincide with each other.
- the absorbance Apol (P) derived from azobenzene and the absorbance Apol (V) when tilted by 90 ° are obtained.
- the orientation degree Spol of the cellulose acylate resin is calculated according to the following formula.
- Tg glass transition temperature
- a film piece of 10.0 mg was precisely weighed to 0.01 mg, sealed in an aluminum pan, and set in a sample holder of DSC 6220 (SII Nano Technology Co., Ltd.). An empty aluminum pan was used as a reference.
- the retardation films 1 to 12 produced in Examples 1 to 6 and Comparative Examples 1 to 6 are wavelengths of 450 nm, 550 nm, and 650 nm using Axoscan made by Axometrics in an environment of 23 ° C. and 55% RH.
- the phase difference values Ro (450), Ro (550), and Ro (650) in the in-plane direction were measured, and Ro (450) / Ro (550) was calculated.
- the in-plane orientation angle was also measured using an Axoscan made by Axometrics.
- Wavelength dispersibility Ro (450) / Ro (550) was evaluated according to the following criteria.
- Wavelength dispersibility Ro (550) / Ro (650) was evaluated according to the following criteria.
- the thickness of the film was measured using a commercially available contact-type film thickness meter and evaluated according to the following criteria.
- ⁇ 20 ⁇ m or more and 40 ⁇ m or less ⁇ : Larger than 40 ⁇ m and 60 ⁇ m or less ⁇ : Larger than 60 ⁇ m and 80 ⁇ m or less
- the haze (total haze) of the retardation film was measured with a haze meter (NDH-2000 manufactured by Nippon Denshoku Co., Ltd.) in accordance with JIS K-7136.
- the light source of the haze meter was a 5V9W halogen sphere, and the light receiving part was a silicon photocell (with a relative visibility filter).
- the haze was measured under conditions of 23 ° C. and 55% RH.
- Haze was evaluated according to the following criteria.
- ⁇ 0.2% or less ⁇ : Greater than 0.2% and 0.5% or less ⁇ : Greater than 0.5% and 1.0% or less ⁇ : Greater than 1.0%
- Tear strength A light load tearing device manufactured by Toyo Seiki Co., Ltd. according to JIS K 7128-1991 under the conditions of 23 ° C. and 55% RH. The tear load of the Elmendorf method was applied in both the film slow axis direction and the fast axis direction. It was measured. The average value of the tear load in the slow axis direction and the tear load in the fast axis direction of the film was calculated and evaluated according to the following criteria.
- Display characteristics As described below, display characteristics were evaluated using an organic EL display using the retardation films 1 to 12 prepared in Examples 1 to 6 and Comparative Examples 1 to 6.
- a polyvinyl alcohol film having a thickness of 120 ⁇ m was uniaxially stretched (temperature: 110 ° C., stretch ratio: 5 times). This was immersed in an aqueous solution composed of 0.075 g of iodine, 5 g of potassium iodide and 100 g of water for 60 seconds, and then immersed in an aqueous solution of 68 ° C. composed of 6 g of potassium iodide, 7.5 g of boric acid and 100 g of water. This was washed with water and dried to obtain a polarizer.
- the polarizer, each of the retardation films 1 to 12 produced in Examples 1 to 6 and Comparative Examples 1 to 6 according to the following steps 1 to 5, and a protective film described later on the back side are long.
- Long circularly polarizing plates were produced by laminating with roll-to-roll so as to match the directions.
- Step 1 The retardation film was immersed in a 2 mol / L sodium hydroxide solution at 60 ° C. for 90 seconds, then washed with water and dried to saponify the side to be bonded to the polarizer.
- Step 3 Excess adhesive adhered to the polarizer in Step 2 was gently wiped off and placed on the retardation film treated in Step 1. At that time, a tension of 50 N / m was applied to the retardation film and the polarizer so as not to sag.
- Step 4 The retardation film, the polarizer, and the protective film laminated in Step 3 were bonded at a pressure of 20 to 30 N / cm 2 and a conveyance speed of about 2 m / min.
- Process 5 The sample which bonded the polarizer, retardation film, and protective film which were produced in the process 4 in the 80 degreeC dryer was dried for 2 minutes.
- ⁇ Preparation of protective film> 251 g of 1,2-propylene glycol, 278 g of phthalic anhydride, 91 g of adipic acid, 610 g of benzoic acid, 0.191 g of tetraisopropyl titanate as an esterification catalyst, 2 L four-neck equipped with a thermometer, stirrer, and slow cooling tube The flask was charged and gradually heated with stirring until it reached 230 ° C. in a nitrogen stream. An ester compound was obtained by allowing dehydration condensation reaction for 15 hours, and distilling off unreacted 1,2-propylene glycol under reduced pressure at 200 ° C. after completion of the reaction. The acid value was 0.10 mg KOH / g, and the number average molecular weight was 450.
- the belt casting apparatus was used to uniformly cast on a stainless steel band support.
- the solvent was evaporated until the residual solvent amount reached 100%, and the stainless steel band support was peeled off.
- Cellulose ester film web was evaporated at 35 ° C, slitted to 1.65m width, stretched at 160 ° C while applying heat at 160 ° C, 30% in TD direction (film width direction), MD direction draw ratio was stretched 1%.
- the residual solvent amount when starting stretching was 20%. Then, after drying for 15 minutes while transporting the inside of a drying device at 120 ° C.
- the orientation angle of the protective film was measured using Axoscan manufactured by Axometrics, and as a result, it was in the range of 90 ° ⁇ 1 ° with respect to the film longitudinal direction.
- each organic EL display was produced by bonding to the viewing side of the organic EL cell.
- Table 12 shows the results of the above evaluations and the like together with the conditions for producing the retardation film.
- the additive represented by the general formula (A) is included, Spol is 0.03 or more and 0.15 or less, Sa is larger than 0.15, and Ro (550) is 115 nm or more and 160 nm.
- the orientation angle is not less than 15 ° and not more than 85 ° (Examples 1 to 6)
- the thickness is sufficiently thin compared with the other cases (Comparative Examples 1 to 6).
- a retardation film having high and low haze can be obtained.
- an organic EL display is used using the retardation film, a good display image can be obtained.
- a cellulose acylate film having a sufficiently thin thickness sufficiently suppresses deterioration of brittleness, is excellent in transparency, and is in-plane with respect to light in a wide range of visible light wavelengths.
- a retardation film having a retardation of about 1 ⁇ 4 of the wavelength is provided.
- this retardation film is applied as a circularly polarizing plate to an image display device such as an organic EL display, an image display device capable of displaying a good image with sufficient reflection of external light and the like is provided.
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Abstract
Description
本発明の実施形態に係る位相差フィルムは、セルロースアシレート樹脂と、添加剤とを含む長尺状の位相差フィルムであって、前記添加剤が、上記一般式(A)で表される添加剤であり、吸光分光法により算出される、前記セルロースアシレート樹脂の配向度が、0.03以上0.15以下であり、吸光分光法により算出される、前記添加剤の配向度が、0.15より大きく、前記位相差フィルムの、波長550nmにおける面内位相差値が、115nm以上160nm以下であり、前記位相差フィルムの面内遅相軸と、前記位相差フィルムの長尺方向とがなす角が、15°以上85°以下である。
ここで、Sa=0であることは配向がランダムである(すなわち配向していない)ことを意味し、Sa=1であることは、完全配向であることを意味する。
なお、フィルムのガラス転移温度(Tg)は、例えばDSC-7示差走査カロリメーター(パーキンエルマー社製)や、TAC7/DX熱分析装置コントローラー(パーキンエルマー社製)示差走査熱量計Q2000(TAインスツルメント社製)示差走査熱量計DSC6220(エスアイアイ・ナノテクノロジー株式会社製)などの市販の装置を用いて、示差走査熱量分析方法により測定することができる。
0.83≦Ro(550)/Ro(650)≦0.98 (2)
Ro(450)、Ro(550)、及びRo(650)が上記範囲内であると、より広い波長領域の光に対して、λ/4の位相差を付与することができる。よって、λ/4位相差フィルムとしてより好ましく機能しうる。また、この位相差フィルムを、有機ELディスプレイ等の画像表示装置に適用した場合において、黒表示させた際の光漏れ等を低減しうる。具体的には、上記式(1)を満たすと、青色の再現性が高い。また、上記式(2)を満たすと、赤色の再現性が高い。
式2:Rth={(nx+ny)/2-nz}×d(nm)
(式1、式2中、nxは、位相差フィルムの面内方向において屈折率が最大になる遅相軸方向xにおける屈折率を表し、nyは、位相差フィルムの面内方向において前記遅相軸方向xと直交する方向yにおける屈折率を表し、nzは、位相差フィルムの厚み方向zにおける屈折率を表し、d(nm)は、位相差フィルムの厚みを表す。)
本実施形態で用いるセルロースアシレート樹脂は、セルロースと、カルボン酸とをエステル化反応させて得られる化合物である。すなわち、前記セルロースアシレート樹脂は、セルロースのヒドロキシル基と、カルボン酸のカルボキシル基とを脱水縮合させて、アシル基を形成させて得られる化合物である。また、カルボン酸は、特に限定されないが、炭素数2~22程度の脂肪族カルボン酸、及び炭素数2~22程度の芳香族カルボン酸等が挙げられる。この中でも、炭素数6以下の低級脂肪酸が好ましい。また、カルボン酸は、単独で用いてもよいが、2種以上組合せて用いてもよい。
カラム:Shodex K806、K805、K803G(昭和電工株式会社製)を3本接続して使用する;
カラム温度:25℃;
試料濃度:0.1質量%;
検出器:RI Model 504(GLサイエンス社製);
ポンプ:L6000(日立製作所株式会社製);
流量:1ml/分
校正曲線:標準ポリスチレンSTK standard ポリスチレン(東ソー株式会社製)の、Mw=1000000~500の範囲にある13サンプルによる校正曲線を使用する。13サンプルは、ほぼ等間隔に用いる。
本実施形態で用いる添加剤は、上記一般式(A)で表される添加剤である。
上記の化合物No.5は、下記式に従って、合成することができる。
糖エステル化合物は、フラノース構造もしくはピラノース構造を1~12個有する化合物であって、該化合物中の水酸基の全部または一部がエステル化された化合物である。
ビス(2,2,6,6-テトラメチル-4-ピペリジル)セバケート、ビス(1,2,2,6,6-ペンタメチル-4-ピペリジル)セバケート等のヒンダードアミン系;
2-(3,5-ジ-t-ブチル-4-ヒドロキシベンジル)-2-n-ブチルマロン酸ビス(1,2,2,6,6-ペンタメチル-4-ピペリジル)、1-[2-[3-(3,5-ジ-t-ブチル-4-ヒドロキシフェニル)プロピオニルオキシ]エチル]-4-[3-(3,5-ジ-t-ブチル-4-ヒドロキシフェニル)プロピオニルオキシ]-2,2,6,6-テトラメチルピペリジン等の分子内にヒンダードフェノールとヒンダードアミンの構造を共に有するハイブリッド系のもの;
などが含まれ、好ましくは2-[2-ヒドロキシ-3,5-ビス(α,α-ジメチルベンジル)フェニル]-2-ベンゾトリアゾールや2,2-メチレンビス[4-(1,1,3,3-テトラブチル)-6-(2H-ベンゾトリアゾール-2-イル)フェノール]である。これらは、一種類であっても、二種以上を併用してもよい。
次に、上記した位相差フィルム(λ/4位相差フィルム)の製造方法を説明する。
本実施形態に係る位相差フィルムは、溶液流延法によって製造することができる。溶液流延法では、セルロースアシレート樹脂および添加剤等を有機溶媒に加熱溶解させてドープを調製する工程、調製したドープをベルト状またはドラム状の金属支持体上に流延する工程、流延したドープをウェブとして乾燥する工程、金属支持体から剥離する工程、剥離したウェブを延伸または収縮する工程、さらに乾燥する工程、仕上がったフィルムを巻き取る工程等が含まれる。
ドープ調製工程において、ドープ中のセルロースアシレート樹脂は、濃度が高い方が金属支持体に流延した後の乾燥負荷は低減できて好ましいが、セルロースアシレート樹脂の濃度が高過ぎると濾過時の負荷が増大し、濾過精度が悪くなる。そのため、これらを両立する濃度としては、10~35質量%の範囲内が好ましく、15~25質量%の範囲内がより好ましい。
流延(キャスト)工程において、使用する金属支持体は、表面を鏡面仕上げしたものが好ましく、ステンレススティールベルト、または鋳物で表面をメッキ仕上げしたドラムが好ましく用いられる。
(式中、Mはウェブまたはフィルムを製造中または製造後の任意の時点で採取した試料の質量で、NはMを115℃で1時間の加熱した後の質量である。)
乾燥工程においては、ウェブを金属支持体より剥離してさらに乾燥し、残留溶媒量を1.0質量%以下にすることが好ましく、0~0.01質量%にすることがより好ましい。
本実施形態のλ/4位相差フィルムは、上記のとおり、波長550nmで測定した面内位相差Ro550が115~160nmであることが好ましく、このような位相差はフィルムを延伸することによって付与し得る。
収縮率(%)=(M1-M2)/M1×100
で表される。屈曲角度をθとすると、
M2=M1×sin(π-θ)
となり、収縮率は、
収縮率(%)=(1-sin(π-θ))×100
で表される。
次いで、45°の方向に延伸する斜め延伸方法について、さらに説明する。本実施形態に係るλ/4位相差フィルムの製造方法において、延伸するセルロースアシレートフィルムに斜め方向の配向を付与する方法として、斜め延伸装置を用いることが好ましい。
上記したλ/4位相差フィルムは、溶融製膜法によって製膜してもよい。溶融製膜法は、樹脂および可塑剤などの添加剤を含む組成物を、流動性を呈する温度まで加熱溶融し、その後、流動性の熱可塑性樹脂を含む溶融物を流延する成形方法である。
本実施形態に係る円偏光板(長尺円偏光板)は、長尺状の保護フィルム、長尺状の偏光子および長尺状の上記したλ/4位相差フィルムをこの順に有する長尺ロールを断裁して作製される。本実施形態に係る長尺円偏光板は、上記したλ/4位相差フィルムを用いて作製されるため、後述する有機ELディスプレイ等に適用することにより、可視光波長の広い範囲において、有機EL素子の金属電極の鏡面反射を遮蔽する効果を発現し得る。その結果、観察時の映り込みを防止することができるとともに、黒色表現を向上させることができる。
本実施形態に係る画像表示装置、例えば、有機ELディスプレイ(有機EL画像表示装置)は、上記長尺円偏光板を用いて作製される。より詳細には、本実施形態に係る有機ELディスプレイは、上記λ/4位相差フィルムを用いた長尺円偏光板と、有機EL素子とを備える。有機ELディスプレイの画面サイズは特に限定されず、20インチ以上とすることができる。
0.83≦Ro(550)/Ro(650)≦0.98 (2)
このような構成によれば、可視光波長のより広い範囲の光に対して、面内位相差が波長の1/4程度である位相差フィルムが得られる。
まず、本実施例で用いる樹脂(セルロースアシレート樹脂)について説明する。
次に、本実施例で用いる添加剤について説明する。
次に、本実施例で用いる可塑剤について説明する。
(微粒子添加液の調製)
ドープに添加する微粒子添加液について説明する。
はじめに、加圧溶解タンクに、有機溶媒として、メチレンクロライドとエタノールとを、下記に示す量を添加した。有機溶媒の入った加圧溶解タンクに、下記セルロースアシレート樹脂を攪拌しながら投入した。これを加熱し、攪拌しながら、完全に溶解し、これを安積濾紙(株)製の安積濾紙No.244を使用して濾過し、主ドープを調製した。次いで、一般式(A)で表される化合物として、添加剤1、可塑剤1、及び上記調製した微粒子添加液を以下の比率で、主溶解釜に投入し、密閉した後、攪拌しながら溶解してドープ液を調製した。
メチレンクロライド 340質量部
エタノール 64質量部
セルロースアシレート樹脂1 100質量部
添加剤1 4質量部
可塑剤1 5質量部
微粒子添加液 1質量部
上記のとおり調製したドープを、ステンレスベルト支持体上で、流延し、フィルム中の残留溶媒量が75質量%になるまで溶媒を蒸発させた後、剥離張力130N/mで、ステンレスベルト支持体上からフィルムを剥離した。
この樹脂フィルム原反から、樹脂フィルムを巻き出して、その樹脂フィルムを、図2に記載の構成からなる斜め延伸装置を用いて、延伸温度を185℃、延伸倍率を1.8倍とし、配向角が45°となるように屈曲角度θと収縮率とを調整して斜め延伸した。そうすることによって、フィルムの厚みが40μmのλ/4位相差フィルム1を作製した。
可塑剤として、可塑剤2 4質量部と、可塑剤3 4質量部とを用い、延伸倍率を1.9倍に変更したこと以外、実施例1と同様して、フィルムの厚みが39μmのλ/4位相差フィルム2を作製した。
セルロースアシレート樹脂として、セルロースアシレート樹脂3を用い、延伸温度を210℃、延伸倍率を1.5倍に変更したこと以外、実施例1と同様して、フィルムの厚みが32μmのλ/4位相差フィルム3を作製した。
セルロースアシレート樹脂として、セルロースアシレート樹脂6を用い、延伸温度を200℃、延伸倍率を1.4倍に変更したこと以外、実施例1と同様して、フィルムの厚みが22μmのλ/4位相差フィルム4を作製した。
セルロースアシレート樹脂として、セルロースアシレート樹脂5を用い、添加剤として、添加剤4を用い、延伸温度を180℃、延伸倍率を1.8倍に変更したこと以外、実施例1と同様して、フィルムの厚みが60μmのλ/4位相差フィルム5を作製した。
セルロースアシレート樹脂として、セルロースアシレート樹脂4を用い、添加剤として、添加剤4を用い、延伸温度を175℃、延伸倍率を1.8倍に変更したこと以外、実施例1と同様して、フィルムの厚みが80μmのλ/4位相差フィルム6を作製した。
添加剤として、添加剤2を用い、延伸温度を183℃に変更したこと以外、実施例1と同様して、フィルムの厚みが65μmのλ/4位相差フィルム7を作製した。
セルロースアシレート樹脂として、セルロースアシレート樹脂2を用い、添加剤として、添加剤3を用い、可塑剤として、可塑剤2 4質量部と、可塑剤3 4質量部とを用い、延伸温度を195℃、延伸倍率を2.1倍に変更したこと以外、実施例1と同様して、フィルムの厚みが80μmのλ/4位相差フィルム8を作製した。
セルロースアシレート樹脂として、セルロースアシレート樹脂2を用い、添加剤として、添加剤2を用い、延伸温度を195℃に変更したこと以外、実施例1と同様して、フィルムの厚みが90μmのλ/4位相差フィルム9を作製した。
セルロースアシレート樹脂として、セルロースアシレート樹脂2を用い、添加剤として、添加剤3を用い、可塑剤を17質量部添加し、延伸温度を190℃、延伸倍率を2.1倍に変更したこと以外、実施例1と同様して、フィルムの厚みが85μmのλ/4位相差フィルム10を作製した。
セルロースアシレート樹脂として、セルロースアシレート樹脂3を用い、延伸温度を195℃、延伸倍率を1.4倍に変更したこと以外、実施例1と同様して、フィルムの厚みが32μmのλ/4位相差フィルム11を作製した。
セルロースアシレート樹脂として、セルロースアシレート樹脂3を用い、延伸温度を210℃、延伸倍率を2.0倍に変更したこと以外、実施例1と同様して、フィルムの厚みが30μmのλ/4位相差フィルム12を作製した。
(配向度Spol、Sa)
測定装置
分光光度計V-7100(日本分光株式会社製)の光源側に紫外域対応の偏光子(消光比1×10-5のグランテーラープリズム)を設置し、検出側に積分球が無いことを確認し、市販の偏光解消フィルターを設置した。
実施例1~6、比較例1~6で作成した位相差フィルム1~12をそれぞれ、上記装置に設置して、220~450nmの波長域で、吸収スペクトルを測定した。このとき、偏光子の透過軸に対してフィルムの遅相軸方向が一致するようにサンプルを設置してスペクトルを測定し、添加剤由来の吸収の吸光度Aa(P)を求めた。さらに、偏光子の透過軸に対してフィルムの遅相軸方向が90°になるようにサンプルを設置した状態でも、同じようにスペクトルを測定し、添加剤由来の吸収の吸光度Aa(V)を求めた。
実施例1~6、比較例1~6で作成した位相差フィルム1~12の添加剤1~4の代わりに、アゾベンゼンを10%添加した以外は、実施例1~6、比較例1~6と同様の条件で作成してSpol測定用フィルム1′~12’を作成した。ただし延伸温度は、位相差フィルム1~12のガラス転移温度と各々の延伸温度との差と、Spol測定用フィルム1′~12’のガラス転移温度と延伸温度との差とが等しくなるように、Spol測定用フィルム1′~12’の延伸温度を設定した。作成したSpol測定用フィルムを、Saを算出するときと同様に、光源側に偏光子が配置された上記分光光度計に設置し、偏光子の透過軸とフィルムの遅相軸方向が一致する向きのアゾベンゼン由来の吸光度Apol(P)と、90°傾けたときの吸光度Apol(V)を求める。
なお、フィルムのガラス転移温度(Tg)は、示差走査熱量計DSC6220(エスアイアイ・ナノテクノロジー株式会社製)を用いて次のように測定した。
上記実施例1~6、及び比較例1~6で作製した位相差フィルム1~12について、23℃、55%RH環境下で、Axometrics社製のAxoscanを用いて、450nm、550nm、650nmの波長での面内方向の位相差値Ro(450)、Ro(550)、Ro(650)を測定し、Ro(450)/Ro(550)を算出した。面内配向角についても、Axometrics社製のAxoscanを用いて測定した。
○:0.72≦Ro(450)/Ro(550)<0.81、0.89<Ro(450)/Ro(550)≦0.94
×:Ro(450)/Ro(550)<0.72、0.94<Ro(450)/Ro(550)
○:0.83≦Ro(550)/Ro(650)<0.85、0.95<Ro(550)/Ro(650)≦0.98
×:Ro(550)/Ro(650)<0.83、0.98<Ro(550)/Ro(650)
フィルムの厚みは、市販の接触式膜厚計を用いて測定し、以下の基準で評価した。
○:40μmより大きく60μm以下
△:60μmより大きく80μm以下
×:80μmより大きい
位相差フィルムのヘイズ(全ヘイズ)は、JIS K-7136に準拠して、ヘイズメーター(日本電色株式会社製NDH-2000)にて測定した。ヘイズメーターの光源は、5V9Wのハロゲン球とし、受光部は、シリコンフォトセル(比視感度フィルター付き)とした。ヘイズの測定は、23℃55%RHの条件下にて行った。
○:0.2%より大きく0.5%以下
△:0.5%より大きく1.0%以下
×:1.0%より大きい
23℃、55%RHの条件下で、JIS K 7128-1991に従い東洋精機(株)製の軽荷重引き裂き装置で、フィルム遅相軸方向、進相軸方向の両方向においてエレメンドルフ法の引き裂き荷重を測定した。フィルムの遅相軸方向の引き裂き荷重と進相軸方向の引き裂き荷重の平均値を算出し、以下の基準で評価した。
×:40mNより小さい
以下のように、上記実施例1~6、及び比較例1~6で作製した位相差フィルム1~12を用いた、有機ELディスプレイを用いて、表示特性を評価した。
厚さ、120μmのポリビニルアルコールフィルムを、一軸延伸(温度110℃、延伸倍率5倍)した。これをヨウ素0.075g、ヨウ化カリウム5g、水100gからなる水溶液に60秒間浸漬し、次いでヨウ化カリウム6g、ホウ酸7.5g、水100gからなる68℃の水溶液に浸漬した。これを水洗、乾燥し偏光子を得た。
工程1:位相差フィルムを60℃の2モル/Lの水酸化ナトリウム溶液に90秒間浸漬し、次いで水洗し乾燥して、偏光子と貼合する側を鹸化した。
工程2:前記偏光子を固形分2質量%のポリビニルアルコール接着剤槽中に1~2秒浸漬した。
工程3:工程2で偏光子に付着した過剰の接着剤を軽く拭き除き、これを工程1で処理した位相差フィルムの上にのせて配置した。その際、たるみが生じないように位相差フィルムと偏光子に50N/mの張力を掛けた。
工程4:工程3で積層した位相差フィルムと偏光子と保護フィルムを圧力20~30N/cm2、搬送スピードは約2m/分で貼合した。
工程5:80℃の乾燥機中に工程4で作製した偏光子と位相差フィルムと保護フィルムとを貼り合わせた試料を2分間乾燥した。
(エステル化合物の調製)
1,2-プロピレングリコール251g、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した。15時間脱水縮合反応させ、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、エステル化合物を得た。酸価0.10mgKOH/g、数平均分子量450であった。
セルロースアセテート(アセチル基置換度2.88) 90質量部
エステル化合物 10質量部
チヌビン928(BASFジャパン(株)製) 2.5質量部
微粒子添加液 4質量部
メチレンクロライド 432質量部
エタノール 38質量部
以上を密閉容器に投入し、加熱し、撹拌しながら、完全に溶解し、安積濾紙(株)製の安積濾紙No.24を使用して濾過し、ドープ液を調製した。
次に、ベルト流延装置を用い、ステンレスバンド支持体に均一に流延した。ステンレスバンド支持体で、残留溶剤量が100%になるまで溶剤を蒸発させ、ステンレスバンド支持体上から剥離した。セルロースエステルフィルムのウェブを35℃で溶剤を蒸発させ、1.65m幅にスリットし、160℃の熱をかけながら延伸装置でTD方向(フィルムの幅手方向)に30%、MD方向の延伸倍率は1%延伸した。延伸を始めたときの残留溶剤量は20%であった。その後、120℃の乾燥装置内を多数のローラで搬送させながら15分間乾燥させた後、1.49m幅にスリットし、フィルム両端に幅15mm、高さ10μmのナーリング加工を施し、巻芯に巻き取り、保護フィルムを得た。保護フィルムの残留溶剤量は0.2%であり、膜厚は40μm、巻数は3900mであった。保護フィルムの配向角は、Axometorics社製Axoscanを用いて測定した結果、フィルム長尺方向に対して90°±1°の範囲にあった。
3mm厚の50インチ(127cm)用無アルカリガラスを用いて、特開2010-20925号公報の実施例に記載されている方法に準じて、同公報の図8に記載された構成からなる有機ELセルを作製した。
上記のとおり作製したそれぞれの円偏光板の位相差フィルムの表面に接着剤を塗工した後、有機ELセルの視認側に貼合することでそれぞれの有機ELディスプレイを作製した。
上記のとおり作製したそれぞれの有機ELディスプレイについて、以下の評価を行った。
23℃、55%RHの環境で、有機ELディスプレイの最表面から5cm高い位置での照度が1000Lxとなる条件下で、有機ELディスプレイに黒画像を表示した。次いで、表示した黒画像について、有機ELディスプレイの正面位置(面法線に対し0°)と、面法線に対し40°の斜め角度からの黒画像の視認性を、一般モニター10人により以下の基準に従って評価した。△以上であれば、実用上問題ない。
○:8人以上のモニターが、表示された画像が黒であると判定した
△:6人以上のモニターが、表示された画像が黒であると判定した
×:5人以下のモニターが、表示された画像が黒であると判定した。
Claims (6)
- セルロースアシレート樹脂と、添加剤とを含む長尺状の位相差フィルムであって、
前記添加剤が、下記一般式(A)で表される添加剤であり、
吸光分光法により算出される、前記セルロースアシレート樹脂の配向度が、0.03以上0.15以下であり、
吸光分光法により算出される、前記添加剤の配向度が、0.15より大きく、
前記位相差フィルムの、波長550nmにおける面内位相差値が、115nm以上160nm以下であり、
前記位相差フィルムの面内遅相軸と、前記位相差フィルムの長尺方向とがなす角が、15°以上85°以下であることを特徴とする位相差フィルム。
- 前記セルロースアシレート樹脂が、グルコース単位当たりのアシル基の総炭素数が6.5個以下である請求項1に記載の位相差フィルム。
- 前記位相差フィルムの、波長450nmにおける面内位相差値Ro(450)と、波長550nmにおける面内位相差値Ro(550)と、波長650nmにおける面内位相差値Ro(650)とが、下記式(1)及び下記式(2)を満たす請求項1又は請求項2に記載の位相差フィルム。
0.72≦Ro(450)/Ro(550)≦0.94 (1)
0.83≦Ro(550)/Ro(650)≦0.98 (2) - 前記セルロースアシレート樹脂のアシル基のグルコース単位当たりの総置換度が、1.5以上2.5以下である請求項1~3のいずれか1項に記載の位相差フィルム。
- 請求項1~4のいずれか1項に記載の位相差フィルムを備える円偏光板。
- 請求項1~4のいずれか1項に記載の位相差フィルムを備える画像表示装置。
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US10071979B2 (en) | 2010-04-22 | 2018-09-11 | Vertex Pharmaceuticals Incorporated | Process of producing cycloalkylcarboxamido-indole compounds |
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US11518772B2 (en) | 2018-09-18 | 2022-12-06 | Nikang Therapeutics, Inc. | Fused tricyclic ring derivatives as Src homology-2 phosphate inhibitors |
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JPWO2014068893A1 (ja) | 2016-09-08 |
KR20150048822A (ko) | 2015-05-07 |
KR101677866B1 (ko) | 2016-11-18 |
CN104769465A (zh) | 2015-07-08 |
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