WO2021246094A1 - 積層フィルム、偏光板及び液晶表示装置 - Google Patents
積層フィルム、偏光板及び液晶表示装置 Download PDFInfo
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- WO2021246094A1 WO2021246094A1 PCT/JP2021/016947 JP2021016947W WO2021246094A1 WO 2021246094 A1 WO2021246094 A1 WO 2021246094A1 JP 2021016947 W JP2021016947 W JP 2021016947W WO 2021246094 A1 WO2021246094 A1 WO 2021246094A1
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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
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B23/00—Layered products comprising a layer of cellulosic plastic substances, i.e. substances obtained by chemical modification of cellulose, e.g. cellulose ethers, cellulose esters, viscose
- B32B23/04—Layered products comprising a layer of cellulosic plastic substances, i.e. substances obtained by chemical modification of cellulose, e.g. cellulose ethers, cellulose esters, viscose comprising such cellulosic plastic substance as the main or only constituent of a layer, which is next to another layer of the same or of a different material
- B32B23/08—Layered products comprising a layer of cellulosic plastic substances, i.e. substances obtained by chemical modification of cellulose, e.g. cellulose ethers, cellulose esters, viscose comprising such cellulosic plastic substance as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
- B32B7/02—Physical, chemical or physicochemical properties
- B32B7/023—Optical properties
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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
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/30—Polarising elements
- G02B5/3083—Birefringent or phase retarding elements
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
- G02F1/133528—Polarisers
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
- G02F1/13363—Birefringent elements, e.g. for optical compensation
Definitions
- the present invention relates to a laminated film, a polarizing plate and a liquid crystal display device. More specifically, the present invention relates to a laminated film having good interlayer adhesion in a retardation film having a fumaric acid ester resin layer and capable of ensuring good visibility in a liquid crystal display device using the same. The present invention relates to a polarizing plate and a liquid crystal display device including a laminated film.
- Liquid crystal displays are widely used in society from televisions to personal computers and mobile phones, and are used as important devices.
- various optical compensation films have been used to improve the display characteristics of liquid crystal display devices, and the viewing angle has been expanded, the color tone has been improved, and the contrast has been improved.
- a retardation film having a negative refractive index a film made of a fumaric acid ester resin or containing a fumaric acid ester resin layer has been proposed (see, for example, Patent Document 1).
- the present invention has been made in view of the above problems and situations, and the problem to be solved thereof is that a retardation film having a fumaric acid ester resin layer has good interlayer adhesion and a liquid crystal display using the same. It is an object of the present invention to provide a laminated film capable of ensuring good visibility in a display device and a polarizing plate using the laminated film. Further, it is an object of the present invention to provide a liquid crystal display device capable of ensuring good visibility by using the laminated film.
- the present inventor uses a combination of a specific cellulose acylate and a sugar ester as a constituent material of the base material in the process of examining the cause of the above problem, and uses light having a wavelength of 650 nm of the base material. From the measured out-of-plane phase difference R650 and the out-of-plane phase difference R450 measured with light having a wavelength of 450 nm, the value T (inclination of the out-of-plane phase difference in the wavelength range 450 to 650 nm) obtained based on a specific formula is specified.
- the optical functional layer to be laminated on the base material which is defined in the range, is a polymer in which most of the ester portion is composed substantially of the polymerization unit of fumaric acid ester which is an isopropyl ester, and these base materials and optics.
- a laminated film containing a base material and an optical functional layer The substrate comprises a cellulose acylate having an acyl group substitution degree in the range of 2.6 to 3.0 and a sugar ester in which a hydrogen atom is substituted with an acyl group at 70 to 100% of the hydroxy groups.
- the optical functional layer contains a polymer containing a polymerization unit of fumaric acid ester at a ratio of 90 mol% or more with respect to all the polymerization units, and 80 to 100% of the ester portion of the polymerization unit of the fumaric acid ester is isopropyl.
- Esther The ratio value Rth450 / Rth550 of the out-of-plane retardation Rth450 measured with light having a wavelength of 450 nm and the out-of-plane retardation Rth550 measured with light having a wavelength of 550 nm for the laminated film is within the range of 1.1 to 1.9.
- a laminated film is within the range of 1.1 to 1.9.
- Item 2 The laminated film according to Item 1, wherein the out-of-plane retardation Rth550 measured with light having a wavelength of 550 nm for the laminated film is in the range of -30 to -15 nm.
- a polarizing plate obtained by laminating the laminated film according to the first item or the second item and a polarizing element.
- a liquid crystal display device provided with the polarizing plate according to the third item.
- a polarizing plate using a film can be provided. Further, by using the laminated film, it is possible to provide a liquid crystal display device capable of ensuring good visibility.
- a liquid crystal display device provided with a polarizing plate in which a retardation film having a fumaric acid ester resin layer is combined with a polarizing element on the visual side of the liquid crystal panel
- the light transmitted through the polarizing element and the liquid crystal panel from the backlight is described above. It is presumed that optical compensation with the retardation film of the polarizing plate causes interference with internal reflection and surface reflected light, and that color unevenness occurs when the liquid crystal display device is viewed from an angle. Therefore, it was considered that color unevenness could be suppressed by controlling the wavelength dispersion of the out-of-plane retardation of the retardation film (hereinafter, the out-of-plane retardation of the retardation film is indicated by "Rth").
- the out-of-plane phase difference in the base material to be combined with the fumaric acid ester-based resin layer (hereinafter, the out-of-plane phase difference of the base material is referred to as “R””. Indicated by) was adjusted with the following configuration. Specifically, as a constituent material of the base material, a cellulose acylate having an acyl group substitution degree in the range of 2.6 to 3.0 and a hydrogen atom in which 70 to 100% of the hydroxy groups are substituted with an acyl group are substituted.
- the value T obtained from the out-of-plane phase difference R650 measured with light having a wavelength of 650 nm and the out-of-plane phase difference R450 measured with light having a wavelength of 450 nm is 0 based on the above formula (1). It was configured to be in the range of .040 to 0.055.
- the adhesion between the fumaric acid ester-based resin layer and the base material is such that the ratio of the isopropyl ester in the ester portion in the polymerization unit of the fumaric acid ester in the fumaric acid ester-based resin is 80% or more, and the base material side. It was achieved by setting the ratio of ester substitution of the hydroxy group in the sugar ester of the above to 70% or more. It is considered that the above configuration increased the permeability and interaction between the fumaric acid ester resin layer and the base material.
- FIG. 3 is a cross-sectional view taken along the line XX of the liquid crystal display device shown in FIG.
- the laminated film of the present invention is a laminated film containing a base material and an optical functional layer, wherein the base material contains a cellulose acylate having an acyl group substitution degree in the range of 2.6 to 3.0 and hydroxy.
- the value T obtained based on the above formula (1) is in the range of 0.040 to 0.055, and the optical functional layer has 90 of the polymerization units of the fumaric acid ester with respect to all the polymerization units. It contains a polymer contained in a proportion of mol% or more, and the ester portion of the polymerization unit of the fumaric acid ester is 80 to 100% isopropyl ester, and the out-of-plane retardation Rth450 measured with light having a wavelength of 450 nm for the laminated film. And, the value Rth450 / Rth550 of the ratio to the out-of-plane phase difference Rth550 measured with light having a wavelength of 550 nm is in the range of 1.1 to 1.9. This feature is a technical feature common to each of the following embodiments.
- the out-of-plane retardation Rth550 measured by light having a wavelength of 550 nm for the laminated film is in the range of -30 to -15 nm.
- the polarizing plate of the present invention is characterized in that the laminated film of the present invention and a polarizing element are laminated.
- the liquid crystal display device of the present invention is characterized by comprising the polarizing plate of the present invention.
- the laminated film of the present invention is a laminated film containing a base material and an optical functional layer, and the base material satisfies the following (1-1) and (1-2), and the optical functional layer has the following (2). Satisfied, the laminated film is characterized by satisfying the following (3).
- the substrate is a cellulose acylate having an acyl group substitution degree in the range of 2.6 to 3.0, and a sugar in which a hydrogen atom is substituted with an acyl group in 70 to 100% of the hydroxy groups.
- the value T obtained based on the above equation (1) is a value indicating the slope in the wavelength range of 450 to 650 nm in the graph showing the relationship between the measured wavelength and the out-of-plane phase difference for the base material.
- the value T obtained from the out-of-plane phase difference R650 measured with light having a wavelength of 650 nm and the out-of-plane phase difference R450 measured with light having a wavelength of 450 nm is set to "out-of-plane phase difference”. Also called "tilt T”.
- the optical functional layer contains a polymer containing a polymerization unit of fumaric acid ester at a ratio of 90 mol% or more with respect to all the polymerization units, and the ester portion of the polymerization unit of the fumaric acid ester is 80 to 100.
- the ratio value Rth450 / Rth550 of the laminated film to the out-of-plane retardation Rth450 measured with light having a wavelength of 450 nm and the out-of-plane retardation Rth550 measured with light having a wavelength of 550 nm is 1.1 to 1.9. It is within range.
- the laminated film of the present invention is a laminated film including a base material and an optical functional layer.
- the laminated film of the present invention may contain a layer other than the base material and the optical functional layer as long as the effect of the present invention is not impaired.
- FIG. 1 is a cross-sectional view showing an example of the laminated film of the present invention.
- the laminated film 10 shown in FIG. 1 has a configuration in which the optical functional layer 2 is provided on one main surface of the film-shaped base material 1.
- the laminated film 10 of the present invention may have, for example, an adhesive layer between the base material 1 and the optical functional layer 2.
- the base material 1 may be composed of one layer (single layer) or a plurality of layers, but is a single layer because there is little display unevenness and the thickness can be reduced. Is preferable.
- the components of the laminated film of the present invention will be described in detail.
- the base material is cellulose acylate having an acyl group substitution degree in the range of 2.6 to 3.0 (hereinafter, also referred to as “cellulose acylate (A)”) and hydrogen at 70 to 100% of the hydroxy groups. It contains a sugar ester in which an atom is substituted with an acyl group (hereinafter, also referred to as “sugar ester (B)”). If necessary, the base material may contain other components other than the cellulose acylate (A) and the sugar ester (B) as long as the effects of the present invention are not impaired.
- the substrate contains cellulose acylate (A).
- Cellulose acylate (A) is preferably contained as a main component in the base material.
- the main component means that the content ratio of the cellulose acylate (A) in the base material is 50% by mass or more.
- the content ratio of the cellulose acylate (A) in the base material is preferably 55% by mass or more, more preferably 60% by mass or more, and particularly preferably 70% by mass or more.
- the upper limit of the content ratio of the cellulose acylate (A) in the base material is the remaining amount excluding the constituent components other than the cellulose acylate (A), preferably about 99% by mass, and more preferably 90% by mass.
- Cellulose acylate is a compound in which the hydrogen atom of the hydroxy group of cellulose is replaced with an acyl group.
- the degree of substitution is a value indicating how many of the three hydroxy groups per ⁇ -glucose residue, which is a constituent unit of cellulose, are substituted on average.
- R is preferably an aliphatic hydrocarbon group having 1 to 5 carbon atoms
- R is an acetyl group which is a methyl group
- R is a propionyl group which is an ethyl group.
- a butyryl group in which R is a propyl group is preferable.
- the acyl group of the cellulose acylate (A) may be one kind or two or more kinds.
- the acyl group in the cellulose acylate (A) is preferably one kind, and the one kind is preferably an acetyl group.
- the degree of substitution of the acyl group in the cellulose acylate (A) can be measured according to ASTM-D817-96.
- the degree of acyl group substitution in the cellulose acylate (A) is 2.6 to 3.0, preferably 2.8 to 3.0.
- Cellulose acylate is produced, for example, by the method described below.
- the cellulose acylate (A) is obtained by mixing two or more kinds of cellulose acylates having different degrees of acyl group substitution in the cellulose acylate thus obtained, and is preferably 2.6 to 3.0, preferably 2. It may be adjusted to 8 to 3.0.
- the weight average molecular weight (Mw) of the cellulose acylate (A) is preferably in the range of 80,000 to 300,000, preferably in the range of 120,000 to 250,000, from the viewpoint of maintaining the mechanical strength of the substrate during stretching. Is more preferable. Within the above range, it is easy to control retardation (phase difference) by stretching during film formation of the substrate. Thereby, it is easy to satisfy the above condition (1-2) in the base material.
- the number average molecular weight (Mn) of the cellulose acylate (A) is preferably in the range of 30,000 to 150,000 because the mechanical strength of the obtained base material is high. Further, cellulose acylate having a number average molecular weight of 40,000 to 100,000 is preferably used.
- the value of the ratio (Mw / Mn) of the weight average molecular weight (Mw) of the cellulose acylate (A) to the number average molecular weight (Mn) is preferably in the range of 1.4 to 3.0.
- the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the cellulose acylate (A) can be measured by using, for example, gel permeation chromatography (GPC).
- the measurement conditions are as follows.
- the raw material cellulose of the cellulose acylate (A) used in the present invention may be wood pulp or cotton linter, and the wood pulp may be conifer or hardwood, but conifer is more preferable.
- a cotton linter is preferably used from the viewpoint of peelability during film formation. Cellulose acylates made from these can be appropriately mixed or used alone.
- the ratio of cellulose acylate derived from cotton linter: cellulose acylate derived from wood pulp (coniferous tree): cellulose acylate derived from wood pulp (broad leaf tree) is 100: 0: 0, 90:10: 0, 85:15: 0, 50. : 50: 0, 20:80: 0, 10:90: 0, 0: 100: 0, 0: 0: 100, 80:10: 10, 85: 0: 15, 40:30: 30 can.
- the cellulose acylate (A) according to the present invention can be produced by a known method.
- the cellulose as a raw material is mixed with a predetermined organic acid (acetic acid, propionic acid, etc.), an acid anhydride (acetic anhydride, propionic anhydride, etc.), and a catalyst (sulfuric acid, etc.) to esterify the cellulose to form a cellulose.
- a predetermined organic acid acetic acid, propionic acid, etc.
- an acid anhydride acetic anhydride, propionic anhydride, etc.
- a catalyst sulfuric acid, etc.
- cellulose triester is hydrolyzed as needed to synthesize a cellulose acylate (A) having a desired degree of acyl group substitution (2.6 to 3.0).
- cellulose acylate (A) is completed through steps such as filtration, precipitation, washing with water, dehydration, and drying.
- the cellulose acylate (A) according to the present invention When 1 g of the cellulose acylate (A) according to the present invention was added to 20 ml of pure water (electrical conductivity 0.1 ⁇ S / cm or less, pH 6.8) and stirred at 25 ° C. for 1 hr under a nitrogen atmosphere.
- the pH is preferably in the range of 6 to 7, and the electrical conductivity is preferably in the range of 1 to 100 ⁇ S / cm.
- the cellulose acylate (A) according to the present invention can be specifically synthesized by referring to the method described in JP-A No. 10-45804.
- the base material according to the laminated film of the present invention contains a sugar ester (B) other than the cellulose acylate (A).
- the sugar moiety in the sugar ester (B) according to the present invention is preferably a residue of a sugar having at least 1 to 12 pyranose rings or furanose rings. That is, the sugar ester (B) is preferably a compound obtained by esterifying a sugar having at least 1 to 12 pyranose rings or furanose rings.
- the sugar to be esterified may be a monosaccharide or a polysaccharide in which 2 to 12 sugar structures are linked.
- the sugar ester (B) is a sugar ester in which a hydrogen atom is replaced with an acyl group in 70 to 100% of the hydroxy groups of such sugars.
- the sugar ester (B) is a compound in which at least 70% of the OH groups contained in the raw sugar are esterified.
- esterification rate the ratio in which the hydrogen atom of the hydroxy group in the raw sugar is replaced with an acyl group, that is, the ratio in which the OH group is esterified is referred to as “esterification rate”.
- the esterification rate of the sugar ester (B) is preferably 75% or more, more preferably 100%, of the OH groups present in the pyranose ring or the furanose ring.
- the esterification rate of the sugar ester (B) is 70% or more, good adhesion can be obtained between the base material and the optical functional layer laminated on the base material.
- the content ratio of the sugar ester (B) in the substrate according to the present invention is preferably 1 to 30 parts by mass, more preferably 5 to 20 parts by mass with respect to 100 parts by mass of the cellulose acylate (A).
- the retardation value in the base material can be controlled, and the above condition (1-2) can be easily satisfied.
- raw sugars in the sugar ester (B) include glucose, galactose, mannose, fructose, xylose, or arabinose, lactose, sucrose, nystose, 1F-fructosyl nystose, stachyose, maltotriose, lactitol, lactulose, cellobiose. , Maltos, cellotriose, maltotriose, raffinose, kestose and the like.
- examples of the raw sugar in the sugar ester (B) include gentiobiose, gentiobiose, gentiobiose, xylotriose, galactosylsucrose and the like.
- the raw sugar in the sugar ester (B) preferably contains both a pyranose ring and a furanose ring.
- Preferred examples of the raw sugar in the sugar ester (B) are glucose, sucrose, kestose, varnish, 1F-fructosyl varnish, stachyose and the like, and glucose and sucrose are preferable, and sucrose is more preferable.
- R may be an aliphatic hydrocarbon group, an alicyclic hydrocarbon group or an aromatic hydrocarbon group.
- the monocarboxylic acid for esterification is not particularly limited, and known aliphatic monocarboxylic acids, alicyclic monocarboxylic acids, aromatic monocarboxylic acids and the like can be used. One type of monocarboxylic acid may be used alone, or two or more types may be used in combination.
- aliphatic monocarboxylic acids include acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, caproic acid, enanthic acid, capric acid, pelargonic acid, capric acid, 2-ethyl-hexanecarboxylic acid, undecylic acid, Saturation of lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecic acid, stearic acid, nonadecanic acid, araquinic acid, bechenic acid, lignoseric acid, cellotic acid, heptacosanoic acid, montanic acid, melisic acid, laxelic acid, etc.
- unsaturated fatty acids such as fatty acids, undecylenic acid, oleic acid, sorbic acid, linoleic acid, linolenic acid, arachidonic acid and octeno
- Preferred examples of the alicyclic monocarboxylic acid include cyclopentanecarboxylic acid, cyclohexanecarboxylic acid, cyclooctanecarboxylic acid, and derivatives thereof.
- aromatic monocarboxylic acids include aromatic monocarboxylic acids having an alkyl group or an alkoxy group introduced into the benzene ring of benzoic acid such as benzoic acid and toluic acid, silicic acid, benzylic acid, biphenylcarboxylic acid and naphthalin.
- Aromatic monocarboxylic acids having two or more benzene rings such as carboxylic acids and tetralincarboxylic acids, and derivatives thereof are included.
- aromatic monocarboxylic acids such as xylyl acid, hemeritoic acid, mesitylic acid, prenylic acid, ⁇ -isoduric acid, juric acid, mesitoic acid, ⁇ -isoduric acid, cumic acid, ⁇ -toluic acid and hydroatropa.
- Acids atropic acid, hydrosilicic acid, salicylic acid, o-anisic acid, m-anisic acid, p-anisic acid, cleosortic acid, o-homosalicylic acid, m-homosalicylic acid, p-homosalicylic acid, o-pyrocatechuic acid, ⁇ -resorcilic acid, vanillic acid, isovanic acid, veratrumic acid, o-veratrumic acid, gallic acid, asalonic acid, mandelic acid, homoanisic acid, homovaniphosphoric acid, homoberatrumic acid, o-homoberatrumic acid, phthalonic acid, p-kumalic acid Included; benzoic acid is particularly preferred.
- an oligosaccharide ester compound can also be used as long as the above esterification rate is satisfied.
- Oligosaccharides are produced, for example, by allowing an enzyme such as amylase to act on starch, sucrose and the like.
- Examples of preferred oligosaccharides include maltooligosaccharides, isomaltooligosaccharides, fructooligosaccharides, galactooligosaccharides and xylooligosaccharides.
- sugar ester (B) examples include esterified compounds obtained by condensing 1 to 12 at least one of a pyranose ring or a furanose ring having a structure represented by the following general formula (B).
- R 11 to R 15 and R 21 to R 25 in the general formula (B) represent an acyl group or a hydrogen atom having 2 to 22 carbon atoms.
- m and n are integers of 0 to 12, respectively, and m + n is an integer of 1 to 12.
- the ratio of the acyl group having 2 to 22 carbon atoms to the total number of R 11 to R 15 and R 21 to R 25 is 70 to 100%.
- an acetyl group R 26 is a methyl group
- a benzoyl group are preferable
- R 26 is a phenyl group
- an acetyl group is particularly preferred.
- Examples of the substituent having the phenyl group or the benzyl group include an alkyl group, an alkenyl group, an alkoxyl group and a phenyl group, and these alkyl groups, alkenyl groups and phenyl groups may have a substituent.
- the oligosaccharide ester compound can also be produced in the same manner as other sugar esters.
- the sugar ester (B) is also preferably a sugar ester (B) in which 70% or more of the hydrogen atoms of the OH group are substituted with an acyl group in the following compounds.
- a compound in which 30% or less of R 1 is a hydrogen atom is also a category of sugar ester (B) and is preferable.
- the sugar ester (B) according to the present invention is produced by reacting the above-mentioned sugar, for example, a sugar having at least 1 to 12 pyranose rings or furanose rings with an acylating agent (also referred to as an esterifying agent). It is possible to do.
- the acylating agent include acid halides or acid anhydrides of the various monocarboxylic acids described above. Specifically, when the acyl group is an acetyl group, acetyl chloride, acetic anhydride and the like can be mentioned, and when the acyl group is a benzoyl group, benzyl chloride, benzoic anhydride and the like can be mentioned.
- the degree of substitution and esterification rate of the obtained sugar ester are slightly different between molecules and have a distribution.
- the distribution of the degree of substitution and the esterification rate of the sugar ester is determined by adjusting the amount of the acylating agent, the timing of addition, and the esterification reaction time.
- the desired esterification rate 70-100%) of the sugar ester (B).
- the adjustment of the esterification rate will be specifically described below by exemplifying the reaction of esterifying sucrose with benzoic anhydride.
- the esterification reaction of sucrose with benzoic anhydride was carried out as follows. That is, 34.2 g (0.1 mol) of sucrose (sucrose) and 135.6 g (0.6 mol) of benzoic anhydride were added to a four-headed corben equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen gas introduction tube. ), 284.8 g (3.6 mol) of pyridine was charged, the temperature was raised while bubbling nitrogen gas from the nitrogen gas introduction tube under stirring, and the esterification reaction was carried out at 70 ° C. for 5 hours.
- Kolben was depressurized to 4 ⁇ 10 2 Pa or less, excess pyridine was distilled off at 60 ° C., then the inside of Kolben was depressurized to 1.3 ⁇ 10 Pa or less, and the temperature was raised to 120 ° C. The acid, most of the benzoic acid produced, was distilled off. Then, 1 L of toluene and 300 g of a 0.5 mass% sodium carbonate aqueous solution were added, and the mixture was stirred at 50 ° C. for 30 minutes and then allowed to stand to separate the toluene layer.
- A-5 and the like mean that it is a mixture of all the components having a degree of substitution of 4 or less, that is, compounds having a degree of substitution of 4, 3, 2, or 1.
- the average degree of substitution and the esterification rate were calculated with A-5 and the like as the degree of substitution 4.
- the measurement conditions for HPLC-MS are as follows.
- sugar ester 2 158.2 g (0.70 mol), 146.9 g (0.65 mol), 135.6 g (0.60 mol), 124.3 g (0.55 mol) of benzoic anhydride and this mol of pyridine.
- sugar ester 2, sugar ester 3, and sugar ester 4 were obtained, respectively, having a component composition, an average degree of substitution, and an esterification rate.
- Sugar esters 1 to 4 as a mixture of sugar esters having different degrees of substitution thus obtained are purified by column chromatography using silica gel to obtain 100% purity A-1, A-2, and A, respectively. -3, A-4, A-5 and the like can be obtained.
- a sugar ester having a desired esterification rate (70 to 100%) is selected from the sugar esters 1 to 4 thus prepared, and the sugar ester is selected. Let it be (B). Alternatively, by adding A-1 to A-5 and the like isolated above in combination, a sugar ester (B) adjusted to an esterification rate of 70 to 100% is obtained.
- the base material according to the laminated film of the present invention may contain other components other than the cellulose acylate (A) and the sugar ester (B) as long as the effects of the present invention are not impaired.
- other components include plasticizers, ultraviolet absorbers, antioxidants, fine particles (matting agents), surfactants, polyelectrolytes, conductive complexes, antistatic agents, antiblocking agents, lubricants and the like.
- a known plasticizer having a molecular weight of 10,000 or less can be used as long as the effect of the present invention is not impaired.
- the plasticizer is not particularly limited, but is preferably selected from polyvalent carboxylic acid ester-based plasticizers, glycolate-based plasticizers, phthalate ester-based plasticizers, fatty acid ester-based plasticizers, polyhydric alcohol ester-based plasticizers, and the like. Ester.
- the polyhydric alcohol ester is an ester (alcohol ester) of a dihydric or higher aliphatic polyhydric alcohol and a monocarboxylic acid, and is preferably a 2- to 20-valent aliphatic polyhydric alcohol ester.
- the polyhydric alcohol ester preferably has an aromatic ring or a cycloalkyl ring in the molecule.
- Preferred examples of aliphatic polyhydric alcohols are ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, 1,2-. Butanediol, 1,3-butanediol, 1,4-butanediol, dibutylene glycol, 1,2,4-butanetriol, 1,5-pentanediol, 1,6-hexanediol, hexanetriol, trimethylolpropane , Pentaerythritol, trimethylolethane, xylitol and the like. Of these, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, sorbitol, trimethylolpropane, xylitol and the like are preferable.
- the monocarboxylic acid is not particularly limited and may be an aliphatic monocarboxylic acid, an alicyclic monocarboxylic acid, an aromatic monocarboxylic acid or the like. Alicyclic monocarboxylic acids or aromatic monocarboxylic acids are preferred in order to increase the moisture permeability of the film and prevent it from volatilizing.
- the monocarboxylic acid may be one kind or a mixture of two or more kinds. Further, all of the OH groups contained in the aliphatic polyhydric alcohol may be esterified, or some of them may be left as OH groups.
- the aliphatic monocarboxylic acid is preferably a fatty acid having a linear or side chain having 1 to 32 carbon atoms.
- the aliphatic monocarboxylic acid has more preferably 1 to 20 carbon atoms, still more preferably 1 to 10 carbon atoms.
- Examples of aliphatic monocarboxylic acids include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, capric acid, pelargonic acid, capric acid, 2-ethyl-hexanoic acid, undesic acid, lauric acid, tridecylic acid.
- Saturated fatty acids such as myristic acid, pentadecic acid, palmitic acid, heptadecic acid, stearic acid, nonadecanic acid, araquinic acid, behenic acid, lignoseric acid, cellotic acid, heptacosanoic acid, montanic acid, melicic acid, laxelic acid; It contains unsaturated fatty acids such as oleic acid, sorbic acid, linoleic acid, linolenic acid and arachidonic acid. Among them, acetic acid or a mixture of acetic acid and other monocarboxylic acid is preferable in order to enhance the compatibility with cellulose acetate.
- Examples of the alicyclic monocarboxylic acid include cyclopentanecarboxylic acid, cyclohexanecarboxylic acid, cyclooctanecarboxylic acid and the like.
- aromatic monocarboxylic acids examples include benzoic acid; a benzene ring of benzoic acid introduced with 1 to 3 alkyl or alkoxy groups (eg, methoxy or ethoxy group) (eg, toluic acid); a benzene ring. It contains two or more aromatic monocarboxylic acids (eg, biphenylcarboxylic acid, naphthalincarboxylic acid, tetralincarboxylic acid, etc.), and is preferably benzoic acid.
- aromatic monocarboxylic acids eg, biphenylcarboxylic acid, naphthalincarboxylic acid, tetralincarboxylic acid, etc.
- the polyvalent carboxylic acid ester is an ester of a polyvalent carboxylic acid having a valence of 2 or more, preferably 2 to 20 and an alcohol.
- the polyvalent carboxylic acid is preferably a 2- 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 examples include trivalent or higher aromatic polyvalent carboxylic acids such as trimellitic acid, trimesic acid and pyromellitic acid or derivatives thereof, succinic acid, adipic acid, azelaic acid, sebacic acid and oxalic acid.
- Fat group polycarboxylic acids such as fumaric acid, maleic acid, tetrahydrophthalic acid, tartrate acid, tartronic acid, malic acid, oxypolycarboxylic acids such as citric acid, etc., and suppresses volatilization from the film. Therefore, an oxypolyvalent carboxylic acid is preferable.
- alcohols include aliphatic saturated alcohols having a linear or side chain, aliphatic unsaturated alcohols having a linear or side chain, alicyclic alcohols or aromatic alcohols.
- the aliphatic saturated alcohol or the aliphatic unsaturated alcohol preferably has 1 to 32 carbon atoms, more preferably 1 to 20 carbon atoms, and further preferably 1 to 10 carbon atoms.
- Examples of alicyclic alcohols include cyclopentanol, cyclohexanol and the like.
- aromatic alcohols include benzyl alcohol, cinnamyl alcohol and the like.
- the molecular weight of the polyvalent carboxylic acid ester is not particularly limited, but is preferably in the range of 300 to 1000, and more preferably in the range of 350 to 750.
- the molecular weight of the polyvalent carboxylic acid ester-based plasticizer is preferably large from the viewpoint of suppressing bleed-out; and preferably small from the viewpoint of moisture permeability and compatibility with cellulose acetate.
- polyvalent carboxylic acid esters examples include triethylcitrate, tributylcitrate, acetyltriethylcitrate (ATEC), acetyltributylcitrate (ATBC), benzoyltributylcitrate, acetyltriphenylcitrate, acetyltribenzylcitrate. , Dibutyl tartrate, diacetyldibutyl tartrate, tributyl trimellitate, tetrabutyl pyromellite and the like.
- the polyvalent carboxylic acid ester may be a phthalate ester.
- phthalates include diethyl phthalates, dimethoxyethyl phthalates, dimethyl phthalates, dioctyl phthalates, dibutyl phthalates, di-2-ethylhexyl phthalates, dioctyl phthalates, dicyclohexyl phthalates, dicyclohexyl terephthalates and the like.
- glycolates examples include alkylphthalylalkyl glycolates.
- alkylphthalylalkylglycolates include methylphthalylmethylglycolate, ethylphthalylethylglycolate, propylphthalylpropylglycolate, butylphthalylbutylglycolate, octylphthalyloctylglycolate, and methylphthalyl.
- Ethyl Glycolate, Ethylphthalyl Methyl Glycolate, Ethylphthalylpropyl Glycolate, Methylphthalylbutyl Glycolate, Ethylphthalylbutyl Glycolate, Butylphthalyl Methyl Glycolate, Butylphthalyl EthylGlycolate, Procphthalylbutyl Glycolate, butylphthalylpropylglycolate, methylphthalyloctylglycolate, ethylphthalyloctylglycolate, octylphthalylmethylglycolate, octylphthalylethylglycolate and the like are included, preferably ethylphthalylethylglycolate.
- Ester-based plasticizers include fatty acid esters, citric acid esters, phosphoric acid esters, and the like.
- Examples of fatty acid esters include butyl oleate, methyl acetyl ricinoleate, dibutyl sebacate and the like.
- Examples of citric acid esters include acetyltrimethyl citrate, acetyltriethyl citrate, acetyltributyl citrate and the like.
- Examples of the phosphoric acid ester include triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, biphenyl diphenyl phosphate, trioctyl phosphate, tributyl phosphate and the like, preferably triphenyl phosphate.
- the content of the plasticizer is preferably in the range of 1 to 20 parts by mass, and more preferably in the range of 1.5 to 15 parts by mass with respect to 100 parts by mass of the cellulose acylate (A).
- the content of the plasticizer is within the above range, the effect of imparting plasticity can be exhibited, and the resistance to seepage of the plasticizer from the substrate is also excellent.
- UV absorber When the base material according to the present invention is used as a laminated film as a retardation film arranged on the surface side (visual side) of a liquid crystal display device, it is preferable to contain an ultraviolet absorber from the viewpoint of improving light resistance.
- the ultraviolet absorber aims to improve the light resistance by absorbing ultraviolet rays of 400 nm or less, and in particular, the transmittance at a wavelength of 370 nm is preferably 10% or less, more preferably 5% or less, and further. It is preferably 2% or less.
- the UV absorbers preferably used in the present invention are benzotriazole-based UV absorbers, benzophenone-based UV absorbers, and triazine-based UV absorbers, and particularly preferably benzotriazole-based UV absorbers and benzophenone-based UV absorbers.
- chinubins such as chinubin 928, all of which are commercially available products manufactured by BASF Japan and can be preferably used. Of these, halogen-free ones are preferable.
- a disk-shaped compound such as a compound having a 1,3,5-triazine ring is also preferably used as an ultraviolet absorber.
- the substrate according to the present invention contains an ultraviolet absorber, it can contain one or more of them, and preferably two or more of them.
- a polymer ultraviolet absorber can also be preferably used, and in particular, the polymer type ultraviolet absorber described in JP-A-6-148430 is preferably used.
- the method of adding the ultraviolet absorber is to dissolve the ultraviolet absorber in an alcohol such as methanol, ethanol or butanol, an organic solvent such as methylene chloride, methyl acetate, acetone or dioxolane or a mixed solvent thereof, and then add the ultraviolet absorber to the dope described below. Alternatively, it may be added directly into the dope composition.
- an alcohol such as methanol, ethanol or butanol
- an organic solvent such as methylene chloride, methyl acetate, acetone or dioxolane or a mixed solvent thereof
- the amount of the UV absorber used in the base material is not uniform depending on the type of UV absorber, usage conditions, etc., but when the dry film thickness of the base material is 15 to 50 ⁇ m, it is 0.5 to 0.5 to the base material.
- the range of 10% by mass is preferable, and the range of 0.6 to 4% by mass is more preferable.
- Antioxidants are also called anti-deterioration agents. When the liquid crystal display device or the like is placed in a state of high humidity and high temperature, deterioration of the base material may occur.
- the antioxidant is contained in the base material because it has a role of delaying or preventing the base material from being decomposed by, for example, halogen of the residual solvent amount in the base material or phosphoric acid of the phosphoric acid-based plasticizer. It is preferable to let it.
- a hindered phenol-based compound is preferably used, for example, 2,6-di-t-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di).
- 2,6-di-t-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3 -(3-T-Butyl-5-methyl-4-hydroxyphenyl) propionate] is preferable.
- a hydrazine-based metal inactivating agent such as N, N'-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine or Tris (2,4-di-).
- a phosphorus-based processing stabilizer such as t-butylphenyl) phosphite may be used in combination.
- antioxidants may be used alone or in combination of two or more.
- the amount of the antioxidant added to the substrate is preferably in the range of 1% by mass to 1.0% by mass, more preferably in the range of 10 to 1000% by mass, in terms of mass ratio with respect to the cellulose acylate (A).
- the base material in the laminated film of the present invention may further contain fine particles (matting agent), if necessary, in order to enhance the slipperiness of the surface.
- the fine particles may be inorganic fine particles or organic fine particles.
- inorganic fine particles include silicon dioxide (silica), titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, Includes magnesium silicate, calcium phosphate and the like.
- silicon dioxide and zirconium oxide are preferable, and silicon dioxide is more preferable in order to reduce the increase in haze of the obtained base material.
- Examples of fine particles of silicon dioxide include Aerosil R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, TT600, NAX50 (all manufactured by Nippon Aerosil Co., Ltd.), Seahoster KE-P10, KE-P30. , KE-P50, KE-P100 (all manufactured by Nippon Shokubai Co., Ltd.) and the like are included.
- Aerosil R972V, NAX50, Seahoster KE-P30 and the like are particularly preferable because they reduce the friction coefficient while keeping the turbidity of the obtained base material low.
- the primary particle size of the fine particles is preferably in the range of 5 to 50 nm, more preferably in the range of 7 to 20 nm.
- For the size of the primary particles or their secondary aggregates observe the primary particles or secondary aggregates at a magnification of 500 to 2 million times with a transmission electron microscope, and 100 particles of the primary particles or secondary aggregates. It can be obtained as the average value of the diameter.
- the content of the fine particles in the substrate is preferably in the range of 0.05 to 1.0 parts by mass, and in the range of 0.1 to 0.8 parts by mass with respect to 100 parts by mass of the cellulose acylate (A). It is more preferable to have.
- ⁇ Manufacturing method of base material> As a method for producing the base material according to the laminated film of the present invention, a usual inflation method, T-die method, calendar method, cutting method, casting method, emulsion method, hot press method and the like can be used. From the viewpoints of suppressing coloration, suppressing foreign matter defects, suppressing optical defects such as die lines, etc., the solution casting method and the melt casting film forming method can be selected, and the solution casting method is particularly suitable. , Preferred to obtain a uniform surface.
- Dissolution step In the dissolution step, the cellulose acylate (A) and the sugar ester (B) are required in a dissolving pot in an organic solvent mainly containing a good solvent for the cellulose acylate (A) and the sugar ester (B).
- the step of dissolving or dispersing the other components added according to the above while stirring to form a dope, or adding to the solution of the cellulose acylate (A) the sugar ester (B) according to the present invention and, if necessary.
- This is a step of mixing solutions (dispersions) of other components to form a dope which is a main solution.
- the organic solvent can be used without limitation as long as it can dissolve the cellulose acylate (A) and the sugar ester (B) and can dissolve or disperse the above other components.
- the chlorine-based organic solvent is methylene chloride
- the non-chlorine-based organic solvent is methyl acetate, ethyl acetate, amyl acetate, acetone, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, cyclohexanone, ethyl formate, etc.
- 2,2,2-Trifluoroethanol 2,2,3,3-hexafluoro-1-propanol, 1,3-difluoro-2-propanol, 1,1,1,3,3,3-hexafluoro- 2-Methyl-2-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 2,2,3,3,3-pentafluoro-1-propanol, nitroethane and the like can be mentioned.
- Methylene chloride, methyl acetate, ethyl acetate, and acetone can be preferably used.
- the dope preferably contains 1 to 40% by mass of a linear or branched aliphatic alcohol having 1 to 4 carbon atoms.
- a linear or branched aliphatic alcohol having 1 to 4 carbon atoms.
- the proportion of alcohol in the dope is high, the web gels and easily peels off from the metal support.
- the proportion of alcohol is low, cellulose acylate (A) and sugar in a non-chlorine organic solvent system are used. It also has a role in promoting the dissolution of the ester (B) and other components.
- a total of 15 to 15 to a total of cellulose acylate (A), sugar ester (B) and other components are added to a solvent containing methylene chloride and a linear or branched aliphatic alcohol having 1 to 4 carbon atoms. It is preferably a dope in which 45% by mass is dissolved or dispersed.
- linear or branched aliphatic alcohol having 1 to 4 carbon atoms examples include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, and tert-butanol.
- Ethanol is preferable because of the stability of these internal dopes, the relatively low boiling point, and the good drying property.
- the dissolution or dispersion of the cellulose acylate (A) and the sugar ester (B) and the dissolution or dispersion of other components are carried out under normal pressure, below the boiling point of the main solvent, or pressurized above the boiling point of the main solvent.
- various dissolution methods can be used, such as the method of using the above method, a method of applying pressure above the boiling point of the main solvent is particularly preferable. It is preferable that the dope during or after dissolution of each component is filtered with a filter medium, defoamed, and sent to the next step with a liquid feed pump.
- a filter medium having a collected particle size of 0.5 to 5 ⁇ m and a drainage time of 10 to 25 sec / 100 ml.
- agglomerates remaining at the time of particle dispersion and agglomerates generated at the time of main dope addition are agglomerated by using a filter medium having a collected particle diameter of 0.5 to 5 ⁇ m and a drainage time of 10 to 25 sec / 100 ml. Can only be removed.
- the concentration of the particles is also sufficiently thinner than that of the additive solution, so that the agglomerates do not stick to each other during filtration and the filter pressure does not rise sharply.
- Metal support such as an endless metal belt such as a stainless steel belt or a rotating metal drum that feeds the dope to a pressure die through a liquid feed pump (for example, a pressurized metering gear pump) and transfers it indefinitely. This is a step of spreading the dope from the pressurized die slit to the spreading position on the body.
- a liquid feed pump for example, a pressurized metering gear pump
- a pressure die that can adjust the slit shape of the die base and makes it easy to make the film thickness uniform is preferable.
- the pressure die includes a coat hanger die, a T die, and the like, and any of them is preferably used.
- the surface of the metal support is a mirror surface.
- two or more pressure dies may be provided on the metal support, and the doping amount may be divided and layered.
- Solvent evaporation step This is a step of heating a web (a dope is spread on a casting support and the formed dope film is called a web) on the casting support to evaporate the solvent.
- a method of blowing wind from the web side and / or a method of transferring heat from the back surface of the support with a liquid a method of transferring heat from the front and back surfaces by radiant heat, and the like.
- the drying efficiency is good and preferable.
- a method of combining them is also preferably used. It is preferable to dry the web on the support after casting on the support in an atmosphere of 20 to 100 ° C. In order to maintain the atmosphere at 20 to 100 ° C., it is preferable to blow warm air at this temperature on the upper surface of the web or heat it by means such as infrared rays.
- the amount of residual solvent at the time of peeling the web at a high temperature of about 50 to 70 ° C. is appropriate.
- a method of heat-treating until the temperature falls within the above range is preferable from the viewpoint of keeping the slope T of the out-of-plane phase difference within the above range (1-2).
- the amount of residual solvent in the web at the time of peeling the web from the metal support in the following peeling step shall be in the range of about 20 to 80% by mass depending on the strength of the drying conditions, the length of the metal support, and the like. Is preferable.
- the amount is decided.
- the amount of residual solvent in the web is defined by the following formula.
- Residual solvent amount (mass%) (mass before heat treatment of web-mass after heat treatment of web) / (mass after heat treatment of web) ⁇ 100
- the heat treatment for measuring the amount of residual solvent means that the heat treatment is performed at 140 ° C. for 1 hour.
- the peeling tension when peeling the metal support and the web is usually in the range of 160 to 245 N / m, but when wrinkles are likely to occur during peeling, it is preferable to peel at a tension of 190 N / m or less. ..
- the temperature at the peeling position on the metal support is preferably in the range of ⁇ 50 to 40 ° C, more preferably in the range of 10 to 40 ° C, and in the range of 15 to 30 ° C. Is the most preferable.
- the drying method is generally to blow hot air on both sides of the web, but there is also a method of heating by applying microwaves instead of wind. Too rapid drying tends to impair the flatness of the finished substrate. Drying at high temperature should be performed from a residual solvent of about 8% by mass or less. Throughout, drying is generally carried out within the range of 40-250 ° C. In particular, it is preferable to dry in the range of 40 to 200 ° C.
- the web is formed of the base material in a direction (width direction, TD direction) orthogonal to the transport direction (flow direction, MD direction) so that the thickness of the base material after stretching is within the range of 10 to 50 ⁇ m.
- Tg glass transition temperature
- Tg + 15 glass transition temperature
- the stretching temperature is more preferably in the range of (Tg + 20) to (Tg + 40) ° C.
- the glass transition temperature Tg referred to here is an intermediate point glass transition temperature (Tmg) measured according to JIS K7121 (1987) at a heating rate of 20 ° C./min using a commercially available differential scanning calorimetry device. Is.
- the specific method for measuring the glass transition temperature Tg of the base material is measured using a differential scanning calorimeter DSC220 manufactured by Seiko Instruments Co., Ltd. in accordance with JIS K7121 (1987).
- the present invention it is preferable to prepare a sample on a trial basis in advance using the material constituting the base material and stretch it in the above temperature range with respect to the Tg of the measured base material sample.
- a tenter stretching device When a tenter stretching device is used for stretching, it is preferable to use a device that can independently control the gripping length (distance from the start of gripping to the end of gripping) of the web by the left and right gripping means of the tenter stretching device. Further, in the stretching step, it is also preferable to intentionally create sections having different temperatures in order to improve the flatness.
- the stretching operation may be performed in multiple stages, and it is particularly preferable to carry out biaxial stretching in the spreading direction and the width direction. Further, when biaxial stretching is performed, simultaneous biaxial stretching may be performed, or biaxial stretching may be performed step by step.
- the stretching ratio is preferably in the range of 1.1 to 4 times, preferably 1.2 to 3 times, the original width of the web, which is the sum of the casting direction and the width direction.
- stepwise means, for example, that stretching in different stretching directions can be sequentially performed, stretching in the same direction is divided into multiple stages, and stretching in different directions is added to any of the steps. Is also possible. That is, for example, the following stretching step is also possible.
- Simultaneous biaxial stretching includes stretching in one direction and contracting the other by relaxing tension.
- the preferred draw ratio for simultaneous biaxial stretching is in the range of 1.01 to 1.5 times the original width in both the width direction and the flow direction.
- the amount of residual solvent in the web when dried and stretched by the tenter stretching device is preferably in the range of 20 to 30% by mass when applied to the tenter stretching device, and the amount of residual solvent in the web is 15% by mass or less. It is preferable to dry the product while hanging it on a tenter stretching device.
- the residual solvent amount of the web at the start of stretching is preferably 1 to 15% by mass, more preferably 2 to 10% by mass. Further, it is preferable to dry the web until the residual solvent amount in the winding step is 2% by mass or less, more preferably 0.4% by mass or less.
- the temperature distribution in the width direction of the atmosphere is small from the viewpoint of improving the uniformity of the base material, and the temperature distribution in the width direction in the tenter stretching apparatus is preferably within ⁇ 5 ° C., ⁇ It is more preferably within 2 ° C, and most preferably within ⁇ 1 ° C.
- the base material according to the present invention is a thin film having a preferable thickness in the range of 10 to 50 ⁇ m, there is a concern that the base material may be unwound or deteriorate in optical quality when stored in a roll shape. By embossing, they can be effectively prevented.
- the embossing process is an arbitrary process.
- the embossed portion is a constant structure consisting of minute continuous irregularities on the base material in order to prevent the back surface and the front surface of the wound films from completely adhering to each other before winding the long film. It has a pattern with the width of.
- one surface (for example, the upper surface) of the base material is projected in a convex shape, a relatively concave shape is formed on the other surface (for example, the lower surface) of the base material corresponding to the convex shape.
- the wound base materials are completely adhered to each other or partially adhered to each other to affect the surface condition of the base materials and prevent them from causing a failure.
- Winding process This is a process of winding with a winder as a base material after the amount of residual solvent in the web becomes 2% by mass or less, and dimensional stability is achieved by reducing the amount of residual solvent to 0.4% by mass or less. Good substrate can be obtained. In particular, it is preferable to wind it in the range of 0.00 to 0.10% by mass.
- the winding method a generally used one may be used, and there are a constant torque method, a constant tension method, a taper tension method, a program tension control method with a constant internal stress, etc., and these may be used properly.
- the base material according to the present invention can be obtained as, for example, a long film.
- Specific examples thereof include those having a winding length of about 100 m to 10000 m, and particularly preferably a roll body of a base material having a winding length of 5000 m or more.
- the width of the base material is preferably 1 to 4 m, more preferably 1.4 to 3 m.
- the thickness of the substrate according to the present invention is preferably in the range of 10 to 50 ⁇ m, more preferably in the range of 20 to 40 ⁇ m.
- the substrate according to the present invention has an in-plane phase difference Ro590 defined by the following formula (i) in the range of 0 to 10 nm measured with light having a wavelength of 590 nm under an environment of a temperature of 23 ° C. and a relative humidity of 55%. It is preferable that the out-of-plane phase difference R590 defined by the following formula (ii) is in the range of -20 to 20 nm.
- n x represents the refractive index in the direction x in which the refractive index becomes maximum in the in-plane direction of the film.
- n y in-plane direction of the film, the refractive index in the direction y perpendicular to the direction x.
- n z represents the refractive index in the thickness direction z of the film.
- d represents the thickness (nm) of the film.
- phase differences can be measured using an automatic birefringence meter KOBRA-WPR (Oji measuring instrument).
- the substrate according to the present invention satisfies the above (1-2) with respect to the out-of-plane phase difference. That is, the value T (out-of-plane position) obtained from the out-of-plane phase difference R650 measured with light having a wavelength of 650 nm and the out-of-plane phase difference R450 measured with light having a wavelength of 450 nm for the substrate based on the above equation (1).
- the slope T) of the phase difference is in the range of 0.040 to 0.055.
- the slope T of the out-of-plane phase difference is preferably in the range of 0.045 to 0.050.
- the out-of-plane phase difference R650 and the out-of-plane phase difference R450 can be measured by the same method in the out-of-plane phase difference R590 except that the measurement wavelengths are different.
- the laminated film of the present invention laminated with the optical functional layer has the optical characteristics (1.1 ⁇ Rth450) of the above (3). / Rth550 ⁇ 1.9) can be achieved.
- the substrate according to the present invention preferably has a total haze of less than 1%, more preferably 0.5% or less, and even more preferably 0.2% or less.
- the haze is less than 1%, the transparency of the base material is not deteriorated, and the laminated film of the present invention laminated with the optical functional layer sufficiently functions as an optical (phase difference) film.
- the total haze of the base material can be measured with a haze meter NDH-2000 (manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with JIS K-7136.
- the light source of the haze meter may be a halogen bulb of 5V9W, and the light receiving portion may be a silicon photocell (with a luminous efficiency filter).
- the haze measurement can be performed under the conditions of 23 ° C. and 55% RH.
- the substrate according to the present invention preferably has a total light transmittance of 90% or more, more preferably 93% or more.
- the practical upper limit is about 99%.
- it is necessary to prevent the introduction of additives and copolymerization components that absorb visible light, and to remove foreign substances in the raw material, for example, dope. It is effective to remove it by high-precision filtration to reduce the diffusion and absorption of light inside the substrate.
- the surface roughness of the base material contact part during film formation is reduced to reduce the surface roughness of the base material surface. It is effective to reduce the diffusion and reflection of light on the surface of the base material.
- the optical functional layer contains a polymer containing 90 mol% or more of the polymerization units of fumaric acid ester with respect to all the polymerization units.
- the ester portion of the polymerization unit of fumaric acid ester in the polymer is 80 to 100% isopropyl ester.
- a polymer in which the polymerization unit of fumaric acid ester is contained in a ratio of 90 mol% or more with respect to all the polymerization units and 80 to 100% of the ester portion of the polymerization unit of the fumaric acid ester is an isopropyl ester is a “polymer”. Also called "(F)".
- the optical functional layer may contain other components other than the polymer (F) as long as the effects of the present invention are not impaired.
- the optical functional layer contains the polymer (F).
- the optical functional layer is composed of the polymer (F) except for other components arbitrarily contained.
- the content ratio of the polymer (F) in the optical functional layer is, for example, preferably 90% by mass or more, more preferably 95% by mass or more, and particularly preferably 100% by mass.
- the polymer (F) used in the present invention is a polymer containing the polymerization unit of the fumaric acid ester at a ratio of 90 mol% or more with respect to the total polymerization units, and 80 of the ester portion of the polymerization unit of the fumaric acid ester. It is a polymer in which ⁇ 100% is an isopropyl ester.
- the "polymerization unit” is a unit derived from a monomer constituting the polymer, and is a unit composed of residues in the polymer of the raw material monomer used to prepare the polymer. To say.
- the ratio of the polymerization unit of fumaric acid ester to the total polymerization unit is preferably 95 mol% or more, more preferably 98 mol% or more, and particularly preferably 100 mol%. Further, in the polymer (F), the ratio of the isopropyl ester in the ester portion of the polymerization unit of the fumaric acid ester is preferably 85 to 100%, more preferably 90 to 100%, and particularly preferably 100. %.
- the fumaric acid ester as the monomer which is the source of the polymerization unit may be a monoester in which only one of the two carboxy groups in fumaric acid is esterified. Both carboxy groups may be esterified diesters.
- the polymer (F) it is preferable to use a fumaric acid diester.
- the ester portion of the fumaric acid ester used as the monomer contains an isopropyl ester, and the ratio of the isopropyl ester in the ester portion of the polymerization unit of the fumaric acid ester is within the above range in the entire polymer (F). Is used in combination with a monomer.
- the fumaric acid diester polymerization unit (a) represented by the following general formula (a) is preferable.
- R 1 and R 2 each independently represent an alkyl group having 1 to 12 carbon atoms. However, 80 to 100% of the total number of R 1 and R 2 in the polymer (F) is an isopropyl group.
- the monomer that is the basis of the fumaric acid diester polymerization unit (a) is hereinafter also referred to as “fumaric acid diester (a)”, and R 1 and R 2 are also referred to as “ester groups”.
- the polymer (F) is polymerized by combining fumaric acid diesters (a1) to (a3) classified as follows in fumaric acid diester (a) so that 80 to 100% of the ester groups are isopropyl groups.
- the ratio of the isopropyl group in the ester group is preferably 85 to 100%, more preferably 90 to 100%, and particularly preferably 100%.
- examples of the alkyl group having 1 to 12 carbon atoms other than the isopropyl group in R 1 and R 2 include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, and an n-hexyl.
- Linear alkyl group such as group, s-butyl group, t-butyl group, s-pentyl group, t-pentyl group, s-hexyl group, branched alkyl group such as t-hexyl group, cyclopropyl group, cyclopentyl group , Cyclic alkyl group such as cyclohexyl group.
- These alkyl groups may be substituted with a halogen group such as fluorine or chlorine; an ether group; an ester group or an amino group as long as the effects of the present invention are not impaired.
- the fumaric acid diester (a1) that is, the fumaric acid diisopropyl and the fumaric acid diester (a3) are combined from the viewpoint of ease of production. It is preferable to obtain the polymer (F).
- diisopropyl fumarate and diester fumarate (a3) are used as monomers in the polymerization of the polymer (F)
- the molar percentage of diisopropyl fumarate to the total molar amount of diisopropyl fumarate and diester fumarate (a3) By setting 80 to 100 mol%, 80 to 100% of the ester portion of the polymerization unit of the fumaric acid ester in the polymer (F) can be made into an isopropyl ester.
- Examples of the fumaric acid diester (a3) include dimethyl fumarate, diethyl fumarate, di-n-propyl fumarate, di-n-butyl fumarate, di-n-pentyl fumarate, and di-n-hexyl fumarate.
- Di-s-butyl fumarate, di-t-butyl fumarate, di-s-pentyl fumarate, di-t-pentyl fumarate, di-s-hexyl fumarate, di-t-hexyl fumarate, fumaric acid examples thereof include dicyclopropyl, dicyclopentyl fumarate, dicyclohexyl fumarate and the like, and dimethyl fumarate, diethyl fumarate and the like are preferable.
- Examples of the polymerization unit other than the fumaric acid ester polymerization unit, which may be contained in the polymer (F) at a ratio of 10 mol% or less with respect to the total polymerization unit, include polymerization units based on the following monomers. ..
- the monomer that is the basis of the polymerization unit other than the fumaric acid ester polymerization unit is also referred to as “monomer (b)” below.
- Examples of the monomer (b) include styrenes such as styrene and ⁇ -methylstyrene; (meth) acrylic acid; methyl (meth) acrylate, ethyl (meth) acrylate, and butyl (meth) acrylate.
- (Meta) Acrylic acid esters such as 3-ethyl-3-oxetanylmethyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate; Vinyl esters such as vinyl acetate and vinyl propionate; Acrylonitrile; Methacronitrile; One or more of olefins such as ethylene and propylene; etc. can be mentioned.
- (meth) acrylic acid indicates one or both of acrylic acid and methacrylic acid.
- the polymer (F) used in the present invention has a standard polystyrene-equivalent number average molecular weight (Mn) of 1 ⁇ 10 3 or more obtained from an elution curve measured by gel permeation chromatography (GPC). It is preferably 2 ⁇ 10 4 or more and 2 ⁇ 10 5 or less because it is an optical functional layer having excellent mechanical properties and excellent molding processability at the time of film formation.
- Mn polystyrene-equivalent number average molecular weight
- any method may be used as long as the polymer (F) can be obtained.
- a fumaric acid ester selected so that 80 to 100% of the ester portion of the ester is an isopropyl ester and, if necessary, a monomer (b) of 10 mol% or less of all the monomers, radical polymerization or radical It can be produced by performing copolymerization.
- the fumaric acid ester it is preferable to use a mixture of 80 to 100 mol% of diisopropyl fumarate and 0 to 20 mol% of diisopropyl fumaric acid (a3).
- radical polymerization method to be used a known polymerization method can be used, and for example, any of a bulk polymerization method, a solution polymerization method, a suspension polymerization method, a precipitation polymerization method, an emulsion polymerization method and the like can be adopted. be.
- Examples of the polymerization initiator for performing the radical polymerization method include benzoyl peroxide, lauryl peroxide, octanoyl peroxide, acetyl peroxide, di-t-butyl peroxide, t-butyl cumyl peroxide, and dicumyl peroxide.
- the solvent that can be used in the solution polymerization method, suspension polymerization method, precipitation polymerization method, and emulsion polymerization method is not particularly limited, and aromatic solvents such as benzene, toluene, and xylene; methanol, ethanol, propyl alcohol, and butyl alcohol.
- Aroma-based solvents such as; cyclohexane; dioxane; tetrahydrofuran (THF); acetone; methyl ethyl ketone; dimethylformamide; isopropyl acetate; water and the like, and a mixed solvent thereof can also be mentioned.
- the polymerization temperature at the time of performing radical polymerization can be appropriately set according to the decomposition temperature of the polymerization initiator, and is generally preferably carried out in the range of 40 to 150 ° C.
- the optical functional layer according to the laminated film of the present invention may contain other components other than the polymer (F) as long as the effects of the present invention are not impaired.
- other components include ultraviolet absorbers, antioxidants, fine particles (matting agents), surfactants, polyelectrolytes, conductive complexes, antistatic agents, antiblocking agents, lubricants and the like.
- the optical functional layer according to the present invention contains an antioxidant in order to improve thermal stability.
- the antioxidant include hindered phenol-based antioxidants, phosphorus-based antioxidants, and other antioxidants as described for the above-mentioned substrate, and these antioxidants may be used alone or in combination, respectively. May be used.
- the optical functional layer it is preferable to use a hindered phenolic antioxidant and a phosphorus-based antioxidant in combination because the antioxidant action is synergistically improved.
- the hindered phenolic antioxidant is used. It is particularly preferable to mix 100 to 500 parts by mass of the phosphorus-based antioxidant with 100 parts by mass of the agent.
- the amount of the antioxidant added to the optical functional layer is preferably 0.01 to 10 parts by mass, and particularly preferably 0.5 to 1 part by mass with respect to 100 parts by mass of the polymer (F).
- the same examples as the ultraviolet absorber and fine particles (matting agent) that may be contained in the above-mentioned substrate can be exemplified.
- the optical functional layer is laminated with the above-mentioned base material to obtain the laminated film of the present invention.
- the optical functional layer may be formed into a film by itself, or may be formed into a layer on a substrate.
- the optical functional layer and the base material are laminated by using, for example, an adhesive or the like.
- the optical functional layer is formed into a layer on the substrate, the production of the optical functional layer and the lamination of the optical functional layer and the substrate are performed at the same time.
- an inflation method, a T-die method, a calendar method, a cutting method, a casting method, an emulsion method, or a hot method similar to the method for manufacturing a base material is used.
- a manufacturing method such as a press method can be applied, and a solution casting film forming method and a melt casting film forming method can be selected as preferable methods, and a solution casting method is particularly preferable for obtaining a uniform surface. ..
- a solution (dope) in which the polymer (F) and other components added as necessary are dissolved in a solvent is poured onto a support, and then the solvent is removed by heating or the like. This is a method of obtaining a film.
- the solution viscosity of the dope is an extremely important factor when forming a film having high transparency and excellent thickness accuracy and surface smoothness, and 700 to 30,000 cps is a very important factor. It is preferable, and particularly preferably 1000 to 10000 cps.
- a method for spreading the dope onto the support for example, a T-die method, a doctor blade method, a bar coater method, a roll coater method, a lip coater method, or the like is used.
- the most common method is to continuously extrude the dope from the die onto a belt-shaped or drum-shaped support.
- the support used include a glass substrate; a metal support such as stainless steel or a ferrotype; a plastic support such as polyethylene terephthalate (PET) and triacetyl cellulose (TAC).
- the dope extruded onto the support is made into a film by removing the solvent by heating or the like. In this way, a film-shaped optical functional layer containing the polymer (F) can be obtained.
- the film is peeled off from the support and used.
- melt casting film forming method a mixture of constituents of the optical functional layer containing the polymer (F) is melted in an extruder, extruded into a film from a slit of a T-die, and then rolled or aired. It is a molding method that takes over while cooling.
- Examples of the method of laminating the film-shaped optical functional layer and the base material include a method of bonding using a known adhesive.
- the film-shaped optical functional layer is manufactured as a roll body by the solution casting film forming method as described above, and the base material is manufactured as a roll body as described above, for example, in a continuous roll-to-roll process. It can be bonded using a known adhesive.
- the optical functional layer When the optical functional layer is formed into a layer on the substrate, the optical functional layer can be manufactured by applying the liquid composition for forming the optical functional layer on the substrate and drying it. At the same time, the optical functional layer and the base material are laminated to obtain the laminated film of the present invention.
- a solution (coating solution) in which the polymer (F) and other components added as needed are dissolved in a solvent is prepared.
- the viscosity of the coating solution is an extremely important factor, preferably 10 to 10000 cps, and particularly 10 to 5000 cps. Is preferable.
- the coating method for example, a doctor blade method, a bar coater method, a gravure coater method, a slot die coater method, a lip coater method, a comma coater method, etc. are used.
- the gravure coater method is generally used for thin film coating
- the comma coater method is used for thick film coating.
- a laminated film can be obtained by forming a film as an optical functional layer on the base material by using a base material as a support.
- the laminated surface of the base material with the optical functional layer can be easily bonded by plasma treatment, corona discharge treatment, or the like.
- the thickness of the optical functional layer in the laminated film of the present invention is determined by the phase difference in the thickness direction of the optical functional layer, and is preferably 1 to 30 ⁇ m, more preferably 2 to 20 ⁇ m, and particularly preferably 2 to 10 ⁇ m.
- the laminated film of the present invention satisfies the above (3) with respect to the out-of-plane phase difference. That is, for the laminated film, the ratio value Rth450 / Rth550 of the out-of-plane retardation Rth450 measured with light having a wavelength of 450 nm and the out-of-plane retardation Rth550 measured with light having a wavelength of 550 nm is in the range of 1.1 to 1.9. It is inside. Rth450 / Rth550 is preferably in the range of 1.2 to 1.7.
- the out-of-plane phase difference Rth450 and the out-of-plane phase difference Rth550 can be measured by the same method as the method for measuring the out-of-plane phase difference on the substrate, except that the measurement wavelengths are different.
- the out-of-plane retardation Rth550 is preferably in the range of -30 to -15 nm, and more preferably in the range of -25 to -18 nm. Further, the out-of-plane retardation Rth450 of the laminated film is preferably in the range of ⁇ 40 to ⁇ 15 nm, and more preferably in the range of ⁇ 30 to ⁇ 18 nm.
- the total haze measured by the same method as that of the substrate is preferably less than 1%, more preferably 0.5% or less, and more preferably 0.2% or less. Is more preferable.
- the haze is less than 1%, the transparency of the laminated film does not decrease, and the film functions sufficiently as an optical (phase difference) film.
- the laminated film of the present invention preferably has a total light transmittance of 90% or more, more preferably 93% or more, as measured by the same method as that of the base material.
- the practical upper limit is about 99%.
- the laminated film of the present invention may be provided with functional layers such as an antistatic layer, a backcoat layer, an antireflection layer, a slippery layer, an adhesive layer, an antiglare layer, and a barrier layer, depending on the intended use. Can be provided.
- the polarizing plate of the present invention is characterized in that the laminated film of the present invention and a polarizing element are laminated.
- the polarizing plate of the present invention comprises the laminated film of the present invention, and good visibility can be ensured when used in a liquid crystal display device.
- the polarizing plate of the present invention has, for example, a polarizing element and a laminated film of the present invention arranged on one surface of the polarizing element.
- the structure may have a protective film on the other surface of the polarizing element.
- a polarizing plate having the laminated film of the present invention on both sides of the polarizing element may be used.
- FIG. 2 is a cross-sectional view showing a configuration example of the polarizing plate of the present invention.
- the polarizing plate 20 has a polarizing element 11 and a laminated film 10 arranged on one surface of the polarizing element 11 and a protective film 12 arranged on the other surface.
- the laminated film 10 is formed by laminating a base material 1 and an optical functional layer 2, and is arranged so that the base material 1 side faces one surface of the polarizing element 11.
- the polarizing element 11, the laminated film 10, and the protective film 12 are bonded to each other via an arbitrary adhesive layer (not shown).
- the polarizing element which is the main component of the polarizing plate, is an element that allows only light on the plane of polarization in a certain direction to pass through, and a typical polarizing element currently known is a polyvinyl alcohol-based polarizing film.
- the polyvinyl alcohol-based polarizing film includes a polyvinyl alcohol-based film dyed with iodine and a polyvinyl alcohol-based film dyed with a dichroic dye.
- polarizing element a polarizing element obtained by forming a film of an aqueous polyvinyl alcohol solution and stretching it uniaxially for staining, or dyeing and then uniaxially stretching the film and then subjecting it to durability treatment with a boron compound can be used.
- the film thickness of the polarizing element is preferably in the range of 5 to 30 ⁇ m, and particularly preferably in the range of 5 to 15 ⁇ m.
- the content of ethylene unit described in JP-A-2003-248123 and JP-A-2003-342322 is 1 to 4 mol%
- the degree of polymerization is 2000 to 4000
- the degree of saponification is 99.0 to 99.
- a 99 mol% ethylene modified polyvinyl alcohol film is also preferably used.
- an ethylene-modified polyvinyl alcohol film having a hot water cutting temperature in the range of 66 to 73 ° C. is preferably used.
- the polarizing element using this ethylene-modified polyvinyl alcohol film is excellent in polarization performance and durability performance, has few color spots, and is particularly preferably used in a large liquid crystal display device.
- a coating type polarizing element is produced by the method described in JP-A-2011-160161, Japanese Patent No. 4691205, Japanese Patent No. 4751481, and Japanese Patent No. 4804589, and is bonded to the laminated film of the present invention to form a polarizing plate. Is also preferable.
- the protective film that can be used in the polarizing plate of the present invention can be obtained as a commercially available product, for example.
- a commercially available cellulose acylate film for example, Konica Minolta Tuck KC8UX, KC5UX, KC4UX, KC8UCR3, KC4SR, KC4BR, KC4CR, KC4DR, KC4FR, KC4KR, KC8UY, KC6UKY, KC4UY, KC6UK -HA, KC2UA, KC4UA, KC6UA, KC2UAH, KC4UAH, KC6UAH, and above, manufactured by Konica Minolta Co., Ltd. are preferably used.
- the thickness of the protective film is not particularly limited, but can be about 10 to 100 ⁇ m, preferably in the range of 10 to 80 ⁇ m, more preferably in the range of 10 to 60 ⁇ m, and particularly preferably in the range of 10 to 40 ⁇ m. It is a range.
- the protective film may further have other layers in addition to the film body such as a cellulose acylate film.
- other layers include an antireflection layer, an antistatic layer, a retardation layer, a luminance improving film layer, and the like.
- the adhesive layer may be a layer obtained by drying a completely saponified polyvinyl alcohol aqueous solution (water glue), or may be a cured product layer of an active energy ray-curable adhesive.
- the polarizing plate of the present invention can be manufactured by laminating the laminated film of the present invention and a polarizing element.
- the method for laminating the laminated film and the polarizing element of the present invention is not particularly limited, and the laminated film can be saponified and then a completely saponified polyvinyl alcohol-based adhesive can be used. Further, the laminated film of the present invention and the polarizing element can be bonded by using an active energy ray-curable adhesive or the like.
- the resulting adhesive layer has a high elastic modulus, is easy to suppress deformation of the polarizing plate, and has high resistance to changes in the external environment (heat and humidity, etc.). Is preferable.
- a photoradical polymerization type composition using photoradical polymerization As the active energy ray-curable adhesive for the polarizing plate, a photoradical polymerization type composition using photoradical polymerization, a photocationic polymerization type composition using photocationic polymerization, and photoradical polymerization and photocationic polymerization are used in combination.
- the hybrid type composition is known.
- the photoradical polymerization type composition contains a radically polymerizable compound containing a polar group such as a hydroxy group or a carboxy group described in JP-A-2008-09329 and a radically polymerizable compound not containing a polar group in a specific ratio. Composition) and the like are known.
- the radically polymerizable compound is preferably a compound having an ethylenically unsaturated bond capable of radical polymerization.
- Preferred examples of compounds having a radically polymerizable ethylenically unsaturated bond include compounds having a (meth) acryloyl group.
- Examples of the compound having a (meth) acryloyl group include N-substituted (meth) acrylamide-based compounds, (meth) acrylate-based compounds, and the like.
- “(Meta) acryloyl” means one or both of acryloyl and methacryloyl. The same applies to (meth) acrylamide and (meth) acrylate.
- the photocationic polymerization type composition as disclosed in JP-A-2011-028234, ( ⁇ ) a cationically polymerizable compound, ( ⁇ ) a photocationic polymerization initiator, and ( ⁇ ) a wavelength longer than 380 nm.
- examples thereof include a photosensitizer exhibiting maximum absorption of light and an active energy ray-curable adhesive containing each component of ( ⁇ ) naphthalene-based photosensitizer.
- active energy ray-curable adhesives may be used.
- the polarizing plate has the above-mentioned active energy ray curability on at least one of (1) a pretreatment step of easily adhering the surface to which the polarizing element of the laminated film is bonded and (2) the bonding surface of the polarizing element and the laminated film.
- An adhesive application step of applying an adhesive (3) a bonding step of bonding a polarizing element and an optical film via a obtained adhesive layer, and 4) a polarizing element and an optical film via an adhesive layer. It can be manufactured by a manufacturing method including a curing step of curing the adhesive layer in a state where the adhesive layers are bonded to each other.
- the pretreatment step (1) may be carried out as necessary.
- Pretreatment process In the pretreatment step, an easy-adhesion treatment is performed on the surface of the laminated film that adheres to the polarizing element, for example, the surface of the laminated film on the substrate side.
- the bonding surface of the protective film with the polarizing element is easily bonded together with the laminated film.
- Examples of the easy-adhesion treatment include corona discharge treatment and plasma treatment.
- the active energy ray-curable adhesive is applied to at least one of the adhesive surfaces of the polarizing element and the laminated film.
- the application method is not particularly limited. For example, various coating methods such as a doctor blade, a wire bar, a die coater, a comma coater, and a gravure coater can be used. Further, a method can also be used in which an active energy ray-curable adhesive is cast between the polarizing element and the laminated film, and then pressed with a roller or the like to spread the adhesive uniformly.
- the active energy ray-curable adhesive is similarly applied to at least one of the adhesive surfaces between the polarizing element and the protective film.
- the active energy ray-curable adhesive After applying the active energy ray-curable adhesive in this way, it is subjected to a bonding step.
- this bonding step for example, when the active energy ray-curable adhesive is applied to the surface of the polarizing element in the previous coating step, the laminated film is laminated there.
- the active energy ray-curable adhesive is applied to the surface of the laminated film in the previous coating step, the polarizing element is superimposed there. Further, when the active energy ray-curable adhesive is cast between the polarizing element and the laminated film, the polarizing element and the laminated film are overlapped in that state.
- both sides when the laminated film and the protective film are bonded to both sides of the polarizing element, and when an active energy ray-curable adhesive is used on both sides, the laminated film and the protective film are laminated on both sides of the polarizing element via the active energy ray-curable adhesive.
- the film and the protective film are superposed. And usually, in this state, both sides (when the laminated film is laminated on one side of the polarizing element, the laminate side and the laminated film side, and when the laminated film and the protective film are laminated on both sides of the polarizing element, the same. It is pressed by sandwiching it with a roller or the like from the laminated film on both sides and the protective film side).
- a roller or the like As the material of the roller, metal, rubber or the like can be used.
- the rollers arranged on both sides may be made of the same material or may be made of different materials.
- the uncured active energy ray-curable adhesive is irradiated with active energy rays to cure the adhesive layer to obtain an adhesive layer made of a cured product of the active energy ray-curable adhesive.
- the polarizing element laminated via the active energy ray-curable adhesive is adhered to the laminated film and any protective film.
- the active energy rays may be irradiated from either the polarizing element side or the laminated film side.
- Visible light, ultraviolet rays, X-rays, electron beams and the like can be used as the active energy rays, and since they are easy to handle and have a sufficient curing rate, electron beams or ultraviolet rays are generally preferably used.
- the acceleration voltage is preferably in the range of 5 to 300 kV, and more preferably in the range of 10 to 250 kV. If the acceleration voltage is less than 5 kV, the electron beam may not reach the adhesive and the curing may be insufficient. If the acceleration voltage exceeds 300 kV, the penetrating force through the sample is too strong and the electron beam bounces off, and the laminated film and protection. There is a risk of damaging the film and the stator.
- the irradiation dose is preferably in the range of 5 to 100 kGy, more preferably in the range of 10 to 75 kGy.
- the adhesive When the irradiation dose is less than 5 kGy, the adhesive is insufficiently cured, and when it exceeds 100 kGy, the laminated film, the protective film and the polarizing element are damaged, the mechanical strength is lowered and yellowing occurs, and the predetermined optical characteristics are obtained. Sometimes you can't get it.
- any appropriate conditions can be adopted as long as the adhesive can be cured.
- the dose of ultraviolet rays in the range of 50 ⁇ 1500mJ / cm 2 in accumulated light amount, and even more preferably in the range of within the range of 100 ⁇ 500mJ / cm 2.
- the thickness of the adhesive layer is not particularly limited, but is usually in the range of 0.01 to 10 ⁇ m, preferably in the range of 0.5 to 5 ⁇ m.
- the liquid crystal display device of the present invention is characterized by comprising the polarizing plate of the present invention.
- the liquid crystal display device of the present invention can ensure good visibility by providing the polarizing plate of the present invention using the laminated film of the present invention.
- the liquid crystal display device of the present invention has, for example, the configurations shown in FIGS. 3 and 4.
- FIG. 3 is a plan view of an example of the liquid crystal display device of the present invention
- FIG. 4 is a cross-sectional view taken along the line XX of the liquid crystal display device shown in FIG.
- the liquid crystal display device 100 shown in FIGS. 3 and 4 is arranged on the liquid crystal panel 30, the first polarizing plate 20a arranged on the surface Sa on the visual recognition side of the liquid crystal panel 30, and the surface Sb on the backlight side of the liquid crystal panel 30. It has a second polarizing plate 20b.
- the first polarizing plate 20a and the second polarizing plate 20b are the polarizing plates of the present invention provided with the laminated films 10a and 10b of the present invention, respectively.
- the first polarizing plate of the first polarizing plate 20a and the second polarizing plate 20b is the polarizing plate of the present invention, and both of them are the polarizing plates of the present invention.
- a polarizing plate is more preferable.
- the liquid crystal panel 30 has two glass substrates G and a liquid crystal cell L arranged between them.
- the liquid crystal panel 30 has a TN (Twisted Nematic) mode, an STN (Super Twisted Nematic) mode, an IPS (In-Plane Switching) mode, an OCB (Optically Complete Birefringence) mode, and an ECBlite mode. It can be preferably used for a mode (including MVA; Multi-domin Vertical Birefringence and PVA; Patterned Vertical Birefringence), HAN (Hybrid Defined Nematic) mode, and the like. In order to increase the contrast, VA (MVA, PVA) mode or IPS mode is preferable.
- the rod-shaped liquid crystal molecules are substantially horizontally oriented when no voltage is applied, and are further twisted to 60 to 120 °.
- the TN mode liquid crystal panel is most often used as a color TFT liquid crystal display device, and has been described in many documents.
- the rod-shaped liquid crystal molecules are substantially vertically oriented when no voltage is applied.
- VA mode liquid crystal panel (1) a VA mode liquid crystal panel in a narrow sense (1) in which rod-shaped liquid crystal molecules are oriented substantially vertically when no voltage is applied and substantially horizontally when a voltage is applied (Japanese Patent Laid-Open No. 2-).
- a liquid crystal panel SID97, Voltage of Tech. Papers (Proceedings) 28 (1997) 845 in which the VA mode is multi-domainized for expanding the viewing angle).
- Liquid crystal panel in a mode n-ASM mode
- SURVAIVAL mode liquid crystal panel announced at LCD International 98.
- the OCB mode liquid crystal panel is a bend alignment mode liquid crystal panel in which rod-shaped liquid crystal molecules are oriented in substantially opposite directions (symmetrically) at the upper part and the lower part of the liquid crystal panel. It is disclosed in each specification of No. 541422. Since the rod-shaped liquid crystal molecules are symmetrically oriented at the upper part and the lower part of the liquid crystal panel, the liquid crystal panel in the bend alignment mode has an adaptive optics compensation function. Therefore, this liquid crystal mode is called an OCB (Optically Company Bend) liquid crystal mode.
- the liquid crystal display device in the bend alignment mode has an advantage of a high response speed.
- the IPS mode liquid crystal panel is a method of switching by applying a transverse electric field to the nematic liquid crystal.
- Proc. IDRC Alignment Citron Cell
- the ECB mode liquid crystal panel, rod-shaped liquid crystal molecules are substantially horizontally oriented when no voltage is applied.
- the ECB mode is one of the liquid crystal display modes having the simplest structure, and details are described in, for example, Japanese Patent Application Laid-Open No. 5-203946.
- the first polarizing plate 20a has a first laminated film 10a, a first polarizing element 11a, and a first protective film 12a in order from the surface Sa on the viewing side of the liquid crystal panel 30.
- the first laminated film 10a has a base material 1 and an optical functional layer 2, and the optical functional layer 2 is bonded to the surface Sa on the visual side of the liquid crystal panel 30.
- the second polarizing plate 20b has a second laminated film 10b, a second polarizing element 11b, and a second protective film 12b in order from the surface Sb on the backlight side of the liquid crystal panel 30.
- the second laminated film 10b has a base material 1 and an optical functional layer 2, and the optical functional layer 2 is bonded to the surface Sb on the backlight side of the liquid crystal panel 30.
- the absorption axis of the first polarizing element 11a and the absorption axis of the second polarizing element 11b are orthogonal to each other (they are cross Nicols).
- the liquid crystal panel 30 of the liquid crystal display device 100 has two glass substrates G and a liquid crystal cell L arranged between them.
- the liquid crystal cell L has, for example, a pair of alignment films between a pair of transparent electrodes, a liquid crystal layer between the alignment films, and a color filter inside the glass substrate G on the viewing side. It is a composition.
- the thickness of the glass substrate G is preferably in the range of 0.3 to 0.7 mm, more preferably in the range of 0.3 to 0.5 mm. Since the polarizing plate of the present invention has a small dimensional change due to temperature and humidity, it is particularly preferably used for thin glass used for small and medium-sized mobile electronic devices.
- the surface of the optical functional layer 2 of the first laminated film 10a, the surface 2a on the visual side of the liquid crystal panel 30, the surface of the optical functional layer 2 of the second laminated film 10b, and the backlight of the liquid crystal panel 30 can be performed by a known method. In some cases, they may be bonded via an adhesive layer (not shown).
- an adhesive layer an adhesive layer obtained by the same active energy ray-curable adhesive as that used in the production of the above-mentioned polarizing plate is preferable.
- the liquid crystal display device of the present invention is of the IPS mode type because the effect of the present invention is more remarkable.
- the liquid crystal display device using the polarizing plate of the present invention is a liquid crystal display device having excellent viewing angle characteristics and excellent visibility in which color unevenness and the like are suppressed by the action of the laminated film of the present invention.
- sugar esters 1 to 5 in which the hydrogen atom of the hydroxy group of the sugar shown in Table III was replaced with the acyl group shown in Table III at the ratio shown in Table III (anhydrous sucrose). It was synthesized according to the esterification reaction with benzoic acid). Specifically, the sugar esters 1, 2 and 5 were prepared by changing benzoic anhydride to acetic anhydride in the above synthesis example and performing an esterification reaction, and adjusting the esterification rate by the same method as described above. The sugar ester 3 was prepared according to the above synthesis example. The sugar ester 4 was prepared by changing sucrose to glucose and benzoic anhydride to acetic anhydride in the above synthesis example to carry out an esterification reaction, and adjusting the esterification rate by the same method as described above.
- sugar esters 1 to 4 are sugar esters corresponding to the sugar ester (B), and the sugar ester 5 is a sugar ester outside the range of the sugar ester (B).
- Dopes 1-9 having the compositions shown in Table IV were prepared. Specifically, first, methylene chloride and ethanol, which are solvents, were added to the pressurized dissolution tank. Cellulose acylate, sugar ester, and matting agent were put into a pressurized dissolution tank containing a solvent with stirring, and the mixture was heated and completely dissolved and dispersed with stirring.
- the matting agents shown in Table IV are all Aerosil R812 12% ethanol dispersions (manufactured by Nippon Aerosil Co., Ltd.).
- the obtained liquid material was used as Azumi Filter Paper No. made by Azumi Filter Paper Co., Ltd. Filtration was performed using 244 to give dope 1-9.
- the peeled web 1 was evaporated with a solvent at 35 ° C., slit to a width of 1.6 m, and then the glass transition temperature of the base material 1 was set to Tg (constituting the base material 1 as described above) using a tenter stretching machine.
- Tg glass transition temperature
- the glass was stretched 1.05 times the original width in the width direction (TD direction) at a temperature of (Tg + 20) ° C.
- the amount of residual solvent when stretching by the tenter stretching machine was started was 4% by mass.
- the drying was completed while transporting the drying zones at 120 ° C. and 140 ° C. with a large number of rollers to prepare the base material 1.
- the thickness of the base material was 40 ⁇ m.
- base materials 2 to 9 having a thickness of 40 ⁇ m were prepared in the same manner except that the dope 1 was changed to the dope 2 to 9.
- the dope 1 prepared above was uniformly cast on a stainless band support at a temperature of 22 ° C. and a width of 1.8 m using a belt casting device. With the stainless band support, the solvent was evaporated at 65 ° C. for 1 minute and then at 40 ° C. until the residual solvent amount reached 20%, and the web 10 was peeled off from the stainless band support at a peeling tension of 162 N / m. Then, in the preparation of the base material 1, the web 10 was stretched and dried in the same manner as the web 1 was stretched and dried to prepare the base material 10 having a thickness of 40 ⁇ m.
- the value T (1) was obtained from the out-of-plane phase difference R650 measured with light having a wavelength of 650 nm and the out-of-plane phase difference R450 measured with light having a wavelength of 450 nm.
- the slope T) of the out-of-plane phase difference was obtained.
- Table V The results are shown in Table V together with the composition of the materials contained in each substrate.
- the amount of the sugar ester added is the amount added to 100 parts by mass of the cellulose acylate.
- ⁇ Synthesis example 1> In a 30 liter autoclave, 18 kg of distilled water containing 0.2% by mass of partially saponified polyvinyl alcohol, 3 kg of diisopropyl fumarate, and 7 g of dimethyl-2,2'-azobisisobutyrate as a polymerization initiator were charged, and the polymerization temperature was increased. The suspension radical polymerization reaction was carried out under the conditions of 50 ° C. and a polymerization time of 24 hours. The obtained particles were filtered, thoroughly washed with methanol and dried at 80 ° C. to obtain a diisopropyl fumarate homopolymer. The number average molecular weight of the obtained diisopropyl fumarate homopolymer was 160000.
- the diisopropyl fumaric acid homopolymer is a fumaric acid ester polymer in which 100% of the ester portion is isopropyl ester.
- the diisopropyl fumarate homopolymer was designated as the fumaric acid ester polymer 1.
- ⁇ Synthesis example 2> In a 1-liter reactor equipped with a stirrer, cooling tube, nitrogen introduction tube and thermometer, 600 g of distilled water, 3.4 g of hydroxypropylmethyl cellulose (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: Metrose 60SH-50) as a dispersant, fumaric acid. Add 350.9 g of diisopropyl, 49.1 g of diethyl fumarate (14.0 parts by mass with respect to 100 parts by mass of diisopropyl fumarate) and 8.3 g of t-butylperoxypivalate, which is an oil-soluble radical initiator, and nitrogen bubbling.
- radical suspension polymerization was carried out by holding at 50 ° C. for 28 hours with stirring at 400 rpm. After completion of the polymerization reaction, the contents were recovered from the reactor, the polymer was filtered off, washed twice with distilled water and twice with methanol, and dried under reduced pressure at 80 ° C. (yield: 75%).
- the number average molecular weight of the obtained fumaric acid ester copolymer was 138,000. 1
- the obtained fumaric acid ester copolymer is a fumaric acid ester copolymer in which 70% of the ester portion is an isopropyl ester.
- This fumaric acid ester copolymer was designated as fumaric acid ester polymer 3.
- a coating solution was prepared by dissolving the fumaric acid ester polymer 1 obtained in Synthesis Example 1 in a solution having a toluene: methyl ethyl ketone mass ratio of 1: 1 as a 10% solution.
- the coating solution obtained on the substrate 1 was applied by a doctor blade method so that the thickness of the layer after drying was 2 ⁇ m, and dried to form an optical functional layer to obtain a laminated film 1.
- Laminated films 2 to 16 are produced in the same manner as above, except that the type of the base material, the type of the fumaric acid ester polymer, and the thickness of the optical functional layer are changed as shown in Table VI in the production of the laminated film 1. did.
- the remaining number is 100 squares ⁇ : The remaining number is 90 squares or more and 99 squares or less ⁇ : The remaining number is 89 squares or less
- polarizing plate Preparation of polarizing plate
- a polarizing plate and a polarizing plate having a structure having a laminated film on one surface and a protective film on the other surface were produced.
- the polarizing element, the laminated film, and the protective film were bonded together using an active energy ray-curable adhesive.
- KC2UA product name, manufactured by Konica Minolta Co., Ltd., cellulose acylate film
- Adhesive 1 Photo-radical polymerization type active energy ray-curable adhesive
- HEAA hydroxyethyl acrylamide, manufactured by Kojin Co., Ltd.
- HEA hydroxyethyl acrylate, manufactured by Kojin Co., Ltd.
- IRGACURE819 manufactured by BASF Japan Co., Ltd. as a photoradical polymerization initiator. 3 parts by mass were mixed and stirred at 50 ° C. for 1 hour to obtain an adhesive 1.
- polarizing plate 1 (Preparation of polarizing plate 1) The surface of the laminated film 1 on the substrate side and one surface of the protective film (KC2UA) were subjected to a corona discharge treatment.
- the conditions for the corona discharge treatment were a corona output strength of 2.0 kW and a line speed of 18 m / min.
- the adhesive 1 prepared as described above was applied to the corona discharge-treated surfaces of the laminated film 1 and the protective film with a bar coater so that the thickness of the adhesive layer after curing was 0.5 ⁇ m.
- the adhesive coated surfaces of the laminated film 1 and the protective film are bonded to both sides of the polarizing element produced as described above, and the laminated film 1 / adhesive 1 coating layer / polarizing element / adhesive 1 coating is applied.
- a layer / protective film (KC2UA) laminate was obtained. From both sides of this laminate, an ultraviolet irradiation device with a belt conveyor (the lamp uses a D-bulb manufactured by Fusion UV Systems) is used to irradiate ultraviolet rays so that the integrated light amount is 750 mJ / cm 2, and adhere.
- the coating layer of the agent 1 was cured to obtain a polarizing plate 1 as an adhesive layer.
- Polarizing plates 2 to 16 were produced in the same manner as the polarizing plate 1 except that the laminated films 2 to 16 were used instead of the laminated film 1.
- a liquid crystal display device was manufactured using the polarizing plates 1 to 16 manufactured above. Specifically, Hitachi's IPS mode LCD TV Woooo W32-L7000 was prepared.
- the schematic cross section of the liquid crystal television has the configuration shown in FIG. 4, and in the liquid crystal television, both the viewing side and the backlight side polarizing plates attached to the glass substrate surface of the liquid crystal panel were peeled off.
- Two polarizing plates 1 produced as described above are prepared, and the optical functional layer surface of the laminated film of each polarizing plate 1 is bonded to the glass substrate surface on the visual recognition side and the backlight side of the liquid crystal panel, respectively, to form a liquid crystal display device 1.
- the absorption axes of the two polarizing plates 1 are in the same direction as the absorption axes of the two polarizing plates attached to the liquid crystal television used, on the visual recognition side and the backlight side, respectively.
- the liquid crystal display device 1 was manufactured by laminating them so as to be.
- Liquid crystal display devices 2 to 16 were manufactured in the same manner as above using the polarizing plates 2 to 16.
- the laminated film of the present invention has good interlayer adhesion, and a liquid crystal display device using a polarizing plate provided with the laminated film can ensure good visibility.
- a laminated film having good interlayer adhesion and ensuring good visibility in a liquid crystal display device using the laminated film and the laminated film in a retardation film having a fumaric acid ester resin layer, a laminated film having good interlayer adhesion and ensuring good visibility in a liquid crystal display device using the laminated film and the laminated film.
- a polarizing plate using the above can be provided. Further, by using the laminated film, it is possible to provide a liquid crystal display device capable of ensuring good visibility.
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Abstract
Description
すなわち、本発明に係る上記課題は、以下の手段により解決される。
前記基材が、アシル基置換度が2.6~3.0の範囲内にあるセルロースアシレートと、ヒドロキシ基の70~100%において水素原子がアシル基に置換された糖エステルを含み、
前記基材について波長650nmの光で測定した面外位相差R650と、波長450nmの光で測定した面外位相差R450とから、下記式(1)に基づいて求められる値Tが0.040~0.055の範囲内にあり、
式(1) T=(R650-R450)/(650-450)
前記光学機能層が、フマル酸エステルの重合単位を全重合単位に対して90モル%以上の割合で含む重合体を含有し、前記フマル酸エステルの重合単位のエステル部は80~100%がイソプロピルエステルであり、
前記積層フィルムについて波長450nmの光で測定した面外位相差Rth450と、波長550nmの光で測定した面外位相差Rth550との比の値Rth450/Rth550が1.1~1.9の範囲内にある積層フィルム。
本発明の積層フィルムは、基材と光学機能層とを含む積層フィルムであって、基材について下記(1-1)及び(1-2)を満足し、光学機能層が下記(2)を満足し、積層フィルムが下記(3)を満足することを特徴とする。
(1-2)前記基材について波長650nmの光で測定した面外位相差R650と、波長450nmの光で測定した面外位相差R450とから、下記式(1)に基づいて求められる値Tが0.040~0.055の範囲内にある。
式(1) T=(R650-R450)/(650-450)
基材は、アシル基置換度が2.6~3.0の範囲内にあるセルロースアシレート(以下、「セルロースアシレート(A)」ともいう。)と、ヒドロキシ基の70~100%において水素原子がアシル基に置換された糖エステル(以下、「糖エステル(B)」ともいう。)を含む。基材は、必要に応じて、本発明の効果を損なわない範囲でセルロースアシレート(A)及び糖エステル(B)以外のその他の成分を含有してもよい。
基材はセルロースアシレート(A)を含有する。セルロースアシレート(A)は、基材において主成分として含有することが好ましい。なお、主成分とは、当該基材中のセルロースアシレート(A)の含有割合が、50質量%以上であることをいう。基材中のセルロースアシレート(A)の含有割合は55質量%以上が好ましく、60質量%以上がより好ましく、特に好ましくは70質量%以上である。基材中のセルロースアシレート(A)の含有割合の上限は、セルロースアシレート(A)以外の構成成分を除いた残量であり、99質量%程度が好ましく、90質量%がより好ましい。
カラム: Shodex K806、K805、K803G(昭和電工(株)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)製)
流量: 1.0ml/分
校正曲線: 標準ポリスチレンSTK standard ポリスチレン(東ソー(株)製)Mw=1000000~500の13サンプルによる校正曲線を使用した。13サンプルは、ほぼ等間隔に用いる。
本発明の積層フィルムに係る基材は、セルロースアシレート(A)以外の糖エステル(B)を含有する。
1)LC部
装置:日本分光(株)製カラムオーブン(JASCO CO-965)、ディテクター(JASCO UV-970-240nm)、ポンプ(JASCO PU-980)、デガッサー(JASCO DG-980-50)
カラム:Inertsil ODS-3 粒子径5μm 4.6×250mm(ジーエルサイエンス(株)製)
カラム温度:40℃
流速:1ml/分
移動相:THF(1%酢酸):H2O(50:50)
注入量:3μl
2)MS部
装置:LCQ DECA(Thermo Quest(株)製)
イオン化法:エレクトロスプレーイオン化(ESI)法
Spray Voltage:5kV
Capillary温度:180℃
Vaporizer温度:450℃
本発明の積層フィルムに係る基材は、必要に応じて、本発明の効果を損なわない範囲でセルロースアシレート(A)及び糖エステル(B)以外のその他の成分を含有してもよい。その他の成分としては、可塑剤、紫外線吸収剤、酸化防止剤、微粒子(マット剤)、界面活性剤、高分子電解質、導電性錯体、帯電防止剤、アンチブロッキング剤、滑剤等が挙げられる。
本発明に係る基材には、分子量が10000以下の公知の可塑剤を、本発明の効果を阻害しない範囲で用いることもできる。可塑剤として特に限定されないが、好ましくは、多価カルボン酸エステル系可塑剤、グリコレート系可塑剤、フタル酸エステル系可塑剤、脂肪酸エステル系可塑剤及び多価アルコールエステル系可塑剤などから選択される。
本発明に係る基材は、積層フィルムとして液晶表示装置の表面側(視認側)に配置する位相差フィルムとして用いる場合に、紫外線吸収剤を含有することが耐光性を向上する観点から好ましい。紫外線吸収剤は400nm以下の紫外線を吸収することで、耐光性を向上させることを目的としており、特に波長370nmでの透過率が10%以下であることが好ましく、より好ましくは5%以下、更に好ましくは2%以下である。
酸化防止剤は劣化防止剤ともいわれる。高湿高温の状態に液晶表示装置等が置かれた場合には、基材の劣化が起こる場合がある。
本発明の積層フィルムにおける基材は、表面の滑り性を高めるため、必要に応じて微粒子(マット剤)をさらに含有してもよい。
本発明の積層フィルムに係る基材の製造方法としては、通常のインフレーション法、T-ダイ法、カレンダー法、切削法、流延法、エマルジョン法、ホットプレス法等の製造法が使用できる。着色抑制、異物欠点の抑制、ダイラインなどの光学欠点の抑制などの観点から製膜方法は、溶液流延製膜法と溶融流延製膜法が選択でき、特に溶液流延法であることが、均一な表面を得るために好ましい。
以下、本発明に係る基材を溶液流延法で製造する場合について説明する。
溶解工程は、セルロースアシレート(A)及び糖エステル(B)に対する良溶媒を主とする有機溶媒に、溶解釜中で当該セルロースアシレート(A)及び糖エステル(B)、必要に応じて添加されるその他の成分を撹拌しながら溶解又は分散しドープを形成する工程、あるいは該セルロースアシレート(A)の溶液に、本発明に係る糖エステル(B)及び必要に応じて添加されるその他の成分の溶液(分散液)を混合して主溶解液であるドープを形成する工程である。
ドープを、送液ポンプ(例えば、加圧型定量ギヤポンプ)を通して加圧ダイに送液し、無限に移送する無端の金属ベルト、例えばステンレスベルト、あるいは回転する金属ドラム等の金属支持体上の流延位置に、加圧ダイスリットからドープを流延する工程である。
ウェブ(流延用支持体上にドープを流延し、形成されたドープ膜をウェブと呼ぶ)を流延用支持体上で加熱し、溶媒を蒸発させる工程である。
なお、残留溶媒量を測定する際の加熱処理とは、140℃で1時間の加熱処理を行うことを表す。
金属支持体上で、ウェブにおける残留溶媒量が上記適量となるまで、例えば20~80質量%、好ましくは20~30質量%となるまで、溶媒を蒸発させたウェブを、剥離位置で剥離する工程である。剥離されたウェブは次工程に送られる。
剥離後、ウェブを乾燥装置内に複数配置したローラーに交互に通して搬送する乾燥装置、及び/又はクリップでウェブの両端をクリップして搬送するテンター延伸装置等を用いて、ウェブを乾燥する。
・幅手方向に延伸→幅手方向に延伸→流延方向に延伸→流延方向に延伸
また、同時二軸延伸には、一方向に延伸し、もう一方を、張力を緩和して収縮させる場合も含まれる。同時二軸延伸の好ましい延伸倍率は幅手方向、流延方向ともに元幅に対して1.01~1.5倍の範囲である。特に好ましくは、リターデーション値を小さくする観点から、幅手方向にフィルム元幅に対して1.01~1.2倍の範囲で延伸することが好ましく、より好ましくは1.05~1.1倍の範囲である。
本発明に係る基材は、好ましい厚さが10~50μmの範囲と薄膜であるため、基材をロール状に保管するときに巻ずれや光学品質の劣化の懸念があるが、エンボス加工することによって、それらを効果的に防止することができる。なお、エンボス加工は任意の工程である。
ウェブ中の残留溶媒量が2質量%以下となってから基材として巻取り機により巻取る工程であり、残留溶媒量を0.4質量%以下にすることにより寸法安定性の良好な基材を得ることができる。特に0.00~0.10質量%の範囲で巻取ることが好ましい。
(位相差(リターデーション値))
本発明に係る基材は、温度23℃、相対湿度55%の環境下で、波長590nmの光で測定した、下記式(i)により定義される面内位相差Ro590が0~10nmの範囲内にあり、下記式(ii)により定義される面外位相差R590が-20~20nmの範囲内にあることが好ましい。
式(ii):R={(nx+ny)/2-nz}×d(nm)
〔式(i)及び式(ii)において、nxは、フィルムの面内方向において屈折率が最大になる方向xにおける屈折率を表す。nyは、フィルムの面内方向において、前記方向xと直交する方向yにおける屈折率を表す。nzは、フィルムの厚さ方向zにおける屈折率を表す。dは、フィルムの厚さ(nm)を表す。〕
本発明に係る基材は、全ヘイズが、1%未満であることが好ましく、0.5%以下であることがより好ましく、0.2%以下であることがより好ましい。ヘイズが1%未満であれば、基材の透明性の低下が無く、光学機能層と積層した本発明の積層フィルムとした際に、光学(位相差)フィルムとして十分に機能する。
本発明に係る基材は、その全光線透過率が90%以上であることが好ましく、より好ましくは93%以上である。また、現実的な上限としては、99%程度である。かかる全光線透過率にて表される優れた透明性を達成するには、可視光を吸収する添加剤や共重合成分を導入しないようにすることや、原料中、例えば、ドープ中の異物を高精度濾過により除去し、基材内部の光の拡散や吸収を低減させることが有効である。また、製膜時の基材接触部(冷却ローラー、カレンダーローラー、ドラム、ベルト、溶液製膜における塗布基材、搬送ローラーなど)の表面粗さを小さくして基材表面の表面粗さを小さくすることにより基材表面の光の拡散や反射を低減させることが有効である。
光学機能層は、フマル酸エステルの重合単位を全重合単位に対して90モル%以上の割合で含む重合体を含有する。当該重合体におけるフマル酸エステルの重合単位のエステル部は80~100%がイソプロピルエステルである。以下、フマル酸エステルの重合単位を全重合単位に対して90モル%以上の割合で含み、当該フマル酸エステルの重合単位のエステル部の80~100%がイソプロピルエステルである重合体を「重合体(F)」ともいう。
光学機能層は重合体(F)を含有する。光学機能層は、任意に含有するその他の成分以外は重合体(F)で構成される。光学機能層における重合体(F)の含有割合は、例えば、90質量%以上が好ましく、95質量%以上がより好ましく、特に好ましくは100質量%である。
フマル酸ジエステル(a2);R1及びR2の一方がイソプロピル基であって、他方がイソプロピル基以外の炭素数1~12のアルキル基である。
フマル酸ジエステル(a3);R1及びR2の両方がイソプロピル基以外の炭素数1~12のアルキル基である。
本発明の積層フィルムに係る光学機能層は、必要に応じて、本発明の効果を損なわない範囲で重合体(F)以外のその他の成分を含有してもよい。その他の成分としては、紫外線吸収剤、酸化防止剤、微粒子(マット剤)、界面活性剤、高分子電解質、導電性錯体、帯電防止剤、アンチブロッキング剤、滑剤等が挙げられる。
本発明において、光学機能層は上記基材と積層されて本発明の積層フィルムとされる。光学機能層は単独でフィルム状に成形されてもよく、基材上で層状に成形されてもよい。光学機能層が単独で成形される場合、光学機能層と基材との積層は、例えば、接着剤等を用いて行う。光学機能層が基材上で層状に成形される場合、光学機能層の製造と、光学機能層と基材との積層は同時に行われる。
(位相差(リターデーション値))
本発明の積層フィルムは、面外位相差に関し、上記(3)を満足する。すなわち、積層フィルムについて、波長450nmの光で測定した面外位相差Rth450と、波長550nmの光で測定した面外位相差Rth550との比の値Rth450/Rth550が1.1~1.9の範囲内にある。Rth450/Rth550は1.2~1.7の範囲にあることが好ましい。
本発明の積層フィルムは、基材と同様の方法で測定される全ヘイズが、1%未満であることが好ましく、0.5%以下であることがより好ましく、0.2%以下であることがより好ましい。ヘイズが1%未満であれば、積層フィルムの透明性の低下が無く、光学(位相差)フィルムとして十分に機能する。
本発明の積層フィルムは、基材と同様の方法で測定される全光線透過率が90%以上であることが好ましく、より好ましくは93%以上である。また、現実的な上限としては、99%程度である。
本発明の積層フィルムには、その用途により、必要に応じて、帯電防止層、バックコート層、反射防止層、易滑性層、接着層、防眩層、及びバリアー層等の機能性層を設けることができる。
本発明の偏光板は、本発明の積層フィルムと偏光子が積層されてなることを特徴とする。本発明の偏光板は本発明の積層フィルムを具備し、液晶表示装置に用いた場合に、良好な視認性を確保できる。
偏光板の主たる構成要素である偏光子は、一定方向の偏波面の光だけを通す素子であり、現在知られている代表的な偏光子は、ポリビニルアルコール系偏光フィルムである。ポリビニルアルコール系偏光フィルムには、ポリビニルアルコール系フィルムにヨウ素を染色させたものと、二色性染料を染色させたものとがある。
本発明の偏光板において使用可能な保護フィルムは、例えば、市販品として入手することができる。保護フィルムとしては、例えば、市販のセルロースアシレートフィルム(例えば、コニカミノルタタック KC8UX、KC5UX、KC4UX、KC8UCR3、KC4SR、KC4BR、KC4CR、KC4DR、KC4FR、KC4KR、KC8UY、KC6UY、KC4UY、KC4UE、KC8UE、KC8UY-HA、KC2UA、KC4UA、KC6UA、KC2UAH、KC4UAH、KC6UAH、以上、コニカミノルタ(株)製)が好ましく用いられる。
接着層は、完全ケン化型ポリビニルアルコール水溶液(水糊)を乾燥させて得られる層であってもよいし、活性エネルギー線硬化性接着剤の硬化物層であってもよい。
本発明の偏光板は本発明の積層フィルムと偏光子を貼合することで製造できる。本発明の積層フィルムと偏光子を貼合する方法は、特に限定はなく、当該積層フィルムを鹸化処理した後、完全鹸化型のポリビニルアルコール系接着剤を用いて行うことができる。また、本発明の積層フィルムと偏光子を貼合は、活性エネルギー線硬化性接着剤等を用いて行うこともできる。得られる接着層の弾性率が高く、偏光板の変形を抑制しやすい点や外部環境の変動(熱湿度等)に対して耐性が高い点などから、活性エネルギー線硬化性接着剤を用いた貼合が好ましい。
前処理工程では、積層フィルムの、偏光子との接着面、例えば積層フィルムの基材側の表面に易接着処理を行う。偏光子の両面にそれぞれ積層フィルムと保護フィルムを接着させる場合は、積層フィルムと併せて保護フィルムの偏光子との接着面に易接着処理を行う。易接着処理としては、コロナ放電処理、プラズマ処理等が挙げられる。
接着剤塗布工程では、偏光子と積層フィルムとの接着面のうち少なくとも一方に、上記活性エネルギー線硬化性接着剤を塗布する。偏光子又は積層フィルムの表面に直接活性エネルギー線硬化性接着剤を塗布する場合、その塗布方法に特別な限定はない。例えば、ドクターブレード、ワイヤーバー、ダイコーター、カンマコーター、グラビアコーター等、種々の塗工方式が利用できる。また、偏光子と積層フィルムの間に、活性エネルギー線硬化性接着剤を流延させた後、ローラー等で加圧して均一に押し広げる方法も利用できる。また、偏光板が保護フィルムを有する場合は、偏光子と保護フィルムとの接着面のうち少なくとも一方に、上記活性エネルギー線硬化性接着剤を同様にして塗布する。
こうして活性エネルギー線硬化性接着剤を塗布した後、貼合工程に供される。この貼合工程では、例えば、先の塗布工程で偏光子の表面に活性エネルギー線硬化性接着剤を塗布した場合、そこに積層フィルムが重ね合わされる。先の塗布工程で積層フィルムの表面に活性エネルギー線硬化性接着剤を塗布した場合は、そこに偏光子が重ね合わされる。また、偏光子と積層フィルムの間に活性エネルギー線硬化性接着剤を流延させた場合は、その状態で偏光子と積層フィルムとが重ね合わされる。
硬化工程では、未硬化の活性エネルギー線硬化性接着剤に活性エネルギー線を照射して、接着剤層を硬化させて活性エネルギー線硬化性接着剤の硬化物からなる接着層とする。それにより、活性エネルギー線硬化性接着剤を介して重ね合わせた偏光子と積層フィルム及び任意の保護フィルムとを接着させる。偏光子の片面に積層フィルムを貼合する場合、活性エネルギー線は、偏光子側又は積層フィルム側のいずれから照射してもよい。また、偏光子の両面にそれぞれ積層フィルム及び保護フィルムを貼合する場合、偏光子の両面にそれぞれ活性エネルギー線硬化性接着剤を介して積層フィルム及び保護フィルムを重ね合わせた状態で、いずれか一方のフィルム側から活性エネルギー線を照射し、両面の活性エネルギー線硬化性接着剤を同時に硬化させるのが有利である。
本発明の液晶表示装置は、本発明の偏光板を具備したことを特徴とする。本発明の液晶表示装置は、本発明の積層フィルムを用いた本発明の偏光板を具備することで、良好な視認性を確保できる。
(1)基材の作製
(1-1)セルロースアシレートの合成
セルロースアシレートとして表IIに示す、種類のアシル基、及びアシル基置換度、数平均分子量(Mn)を有する3種類のセルロースアシレート1~3を、特開平10-45804号公報に記載の方法に従って合成した。なお、セルロースアシレート1及び2がセルロースアシレート(A)に相当するセルロースアシレートであり、セルロースアシレート3はセルロースアシレート(A)の範囲外のセルロースアシレートである。
表IIIに示す糖のヒドロキシ基の水素原子を表IIIに示すアシル基で表IIIに示す割合で置換した糖エステル1~5を上記した合成例(スクロースの無水安息香酸によるエステル化反応)に準じて合成した。具体的には、糖エステル1、2、5は、上記合成例において無水安息香酸を無水酢酸に変更してエステル化反応を行い、上記と同様の方法によりエステル化率を調整して作製した。糖エステル3は上記合成例のとおり作製した。糖エステル4は、上記合成例においてスクロースをグルコースに、及び無水安息香酸を無水酢酸に変更してエステル化反応を行い、上記と同様の方法によりエステル化率を調整して作製した。
積層フィルム用の基材は、以下のとおり溶液流延製膜法により作製した。
表IVに示す組成のドープ1~9を調製した。具体的には、まず、加圧溶解タンクに溶媒であるメチレンクロライドとエタノールを添加した。溶媒の入った加圧溶解タンクにセルロースアシレート、糖エステル、マット剤を撹拌しながら投入し、これを加熱し、撹拌しながら完全に溶解及び分散した。表IVに示すマット剤は、全てアエロジルR812の12%エタノール分散液(日本アエロジル(株)製)である。
上記で調製したドープ1を、ベルト流延装置を用い、温度22℃、1.8m幅で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、40℃で1分、その後60℃で残留溶剤量が20%になるまで溶媒を蒸発させウェブ1として剥離張力162N/mでステンレスバンド支持体上から剥離した。
上記において、ドープ1をドープ2~9に変更した以外は同様にして、いずれも厚さが40μmの基材2~9を作製した。
上記調製したドープ1を、ベルト流延装置を用い、温度22℃、1.8m幅で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、65℃で1分、その後40℃で残留溶剤量が20%になるまで溶媒を蒸発させウェブ10として剥離張力162N/mでステンレスバンド支持体上から剥離した。その後、上記基材1の作製において、ウェブ1を延伸、乾燥したのと同様にしてウェブ10を延伸、乾燥して厚さが40μmの基材10を作製した。
得られた基材1~10について、波長650nmの光で測定した面外位相差R650と、波長450nmの光で測定した面外位相差R450とから、上記式(1)に基づいて値T(面外位相差の傾きT)を求めた。結果を、各基材が含有する材料の構成と共に表Vに示す。なお、表中、糖エステルの添加量はセルロースアシレート100質量部に対する添加量である。
光学機能層用材料として、フマル酸エステル重合体1~3を製造した。
30リットルオートクレーブ中に、部分ケン化ポリビニルアルコール0.2質量%を含む蒸留水18kg、フマル酸ジイソプロピル3kg、重合開始剤として、ジメチル-2,2´-アゾビスイソブチレート7gを仕込み、重合温度50℃、重合時間24時間の条件にて懸濁ラジカル重合反応を行なった。得られた粒子を濾過後、メタノールで十分洗浄し80℃にて乾燥しフマル酸ジイソプロピル単独重合体を得た。得られたフマル酸ジイソプロピル単独重合体の数平均分子量は160000であった。フマル酸ジイソプロピル単独重合体はエステル部の100%がイソプロピルエステルであるフマル酸エステル重合体である。フマル酸ジイソプロピル単独重合体をフマル酸エステル重合体1とした。
撹拌機、冷却管、窒素導入管及び温度計を備えた1リットル反応器に、蒸留水600g、分散剤であるヒドロキシプロピルメチルセルロース(信越化学製、商品名メトローズ60SH-50)3.4g、フマル酸ジイソプロピル350.9g、フマル酸ジエチル49.1g(フマル酸ジイソプロピル100質量部に対し、14.0質量部)及び油溶性ラジカル開始剤であるt-ブチルパーオキシピバレート8.3gを入れ、窒素バブリングを1時間行なった後、400rpmで撹拌しながら50℃で28時間保持することによりラジカル懸濁重合を行なった。重合反応の終了後、反応器より内容物を回収し、重合物をろ別し、蒸留水で2回洗浄およびメタノールで2回洗浄後、80℃で減圧乾燥した(収率:75%)。
上記合成例2において、重合に用いるフマル酸ジイソプロピルとフマル酸ジエチルのモル比を、フマル酸ジイソプロピル:フマル酸ジエチルとして、7:3に変更した以外は上記と同様にして重合を行い、数平均分子量140000、フマル酸ジイソプロピル重合単位/フマル酸ジエチル重合単位=70/30(モル%)であるフマル酸ジイソプロピル・フマル酸ジエチル共重合体を得た。すなわち、得られたフマル酸エステル共重合体は、エステル部の70%がイソプロピルエステルであるフマル酸エステル共重合体である。このフマル酸エステル共重合体をフマル酸エステル重合体3とした。
上記で作製した基材1~10及びフマル酸エステル重合体1~3を用いて以下のとおり積層フィルムを作製した。
合成例1で得られたフマル酸エステル重合体1をトルエン:メチルエチルケトン質量比1:1の溶液に溶解した10%溶液として、塗布溶液を作製した。基材1上に得られた塗布溶液をドクターブレード法にて乾燥後の層の厚さが2μmとなるよう塗布し乾燥して光学機能層を形成し積層フィルム1を得た。
積層フィルム1の作製において、基材の種類、フマル酸エステル重合体の種類、光学機能層の厚さを表VIに示すとおりに変更した以外は、上記と同様にして積層フィルム2~16を作製した。
得られた積層フィルム1~16について、以下のとおり光学特性及び層間密着性を評価した。結果を、作製に用いた基材と光学機能層の種類と共に表VIに示す。なお、表中、「イソプロピル%」はフマル酸エステル重合体中のエステル部におけるイソプロピルエステルが占める割合(%)を示す。
波長450nmの光で測定した面外位相差Rth450と、波長550nmの光で測定した面外位相差Rth550との比の値Rth450/Rth550を求めた。表には、Rth450/Rth550及びRth550を示した。
積層フィルムにおける光学機能層にNTカッターを用いて1mm間隔で縦横それぞれ11本ずつの傷をつけ、100マスのマス目を形成した。この上にセロハン粘着テープ(セロテープ(登録商標)No.405、24mm幅、ニチバン(株)製)を貼って、垂直(90°)方向にすばやく引っ張る剥離試験を行った。このとき、以下の評価基準のように、剥離したマス目の数によって、密着性を評価した。なお、試験は23℃、55%RH環境下で実施した。
◎:残った数が100マス
〇:残った数が90マス以上99マス以下
×:残った数が89マス以下
積層フィルム1~16を用いて、偏光子と、偏光子の一方の面に積層フィルム及び他方の面に保護フィルムを有する構成の偏光板を作製した。なお、偏光子と積層フィルム及び保護フィルムは、活性エネルギー線硬化性接着剤を用いて貼合した。
平均重合度2400、ケン化度99.9モル%の厚さ75μmのポリビニルアルコールフィルムを、30℃の温水中に60秒間浸漬し膨潤させた。次いで、得られたフィルムを、ヨウ素/ヨウ化カリウム(質量比=0.5/8)の濃度0.3%の水溶液に浸漬し、3.5倍まで延伸させながら染色した。その後、得られたフィルムを、65℃のホウ酸エステル水溶液中で、トータルの延伸倍率が6倍となるように延伸した。その後、得られたフィルムを、40℃のオーブンにて3分間乾燥して、厚さ25μmの偏光子を得た。
保護フィルムとして、KC2UA(製品名、コニカミノルタ(株)製、セルロースアシレートフィルム)を準備した。
HEAA(ヒドロキシエチルアクリルアミド、興人社製)を50質量部、HEA(2-ヒドロキシエチルアクリレート、興人社製)を50質量部、及び、光ラジカル重合開始剤として、BASFジャパン社製、IRGACURE819を3質量部混合して、50℃で1時間撹拌し、接着剤1を得た。
積層フィルム1の基材側の表面及び保護フィルム(KC2UA)の一方の表面にコロナ放電処理を施した。コロナ放電処理の条件は、コロナ出力強度2.0kW、ライン速度18m/分とした。次いで、積層フィルム1及び保護フィルムのコロナ放電処理面に、上記のとおり調製した接着剤1を、硬化後の接着層の厚さが0.5μmとなるようにバーコーターで塗工した。
積層フィルム1の代わりに積層フィルム2~16を用いた以外は、偏光板1と同様にして偏光板2~16を作製した。
上記で作製した偏光板1~16を用いて液晶表示装置を作製した。具体的には、日立製IPSモード液晶テレビWooo W32-L7000を準備した。液晶テレビの概略断面は図4に示す構成であり、当該液晶テレビにおいて、液晶パネルのガラス基板面に貼合されていた視認側及びバックライト側の両方の偏光板を剥がした。上記のとおり作製した偏光板1を2枚準備し、各偏光板1の積層フィルムの光学機能層面を、液晶パネルの視認側及びバックライト側のガラス基板面にそれぞれ貼合して液晶表示装置1を作製した。なお、貼合に際しては、2枚の偏光板1の吸収軸が、用いた液晶テレビに貼合されていた2枚の偏光板の吸収軸と、視認側及びバックライト側において、それぞれ同一方向となるように貼り合わせて液晶表示装置1を作製した。偏光板2~16を用いて上記と同様にして液晶表示装置2~16を作製した。
得られた液晶表示装置1~16について、液晶表示装置の電源をONにして、白色画像を映した際の、色味ムラ及び左右色味差を以下のとおり評価することで、斜めからの視認性を評価した。結果を表VIIに示す。
液晶表示装置の視認側に向かって右45°及び左45°から白色画像の画面を目視し色味を確認した。左右のそれぞれについて以下の基準で評価した。
◎:全くムラ見えない。
〇:薄いムラが見えるが視認性に問題ない。
×:ムラが見え視認性に問題あり。
液晶表示装置の視認側に向かって右45°及び左45°から白色画像の画面を目視し色味を確認した際の左右の色味差を以下の基準で評価した。
◎:色味に左右差なし。
〇:色味に若干の左右差があるが気にならない。
×:色味に差がある(例えば、右45°から見たときには青に見え、左45°から見たときには赤に見える。)。
1 基材
2 光学機能層
20、20a、20b 偏光板
11、11a、11b 偏光子
12、12a、12b 保護フィルム
100 液晶表示装置
30 液晶パネル
G ガラス板
L 液晶セル
Claims (4)
- 基材と光学機能層とを含む積層フィルムであって、
前記基材が、アシル基置換度が2.6~3.0の範囲内にあるセルロースアシレートと、ヒドロキシ基の70~100%において水素原子がアシル基に置換された糖エステルを含み、
前記基材について波長650nmの光で測定した面外位相差R650と、波長450nmの光で測定した面外位相差R450とから、下記式(1)に基づいて求められる値Tが0.040~0.055の範囲内にあり、
式(1) T=(R650-R450)/(650-450)
前記光学機能層が、フマル酸エステルの重合単位を全重合単位に対して90モル%以上の割合で含む重合体を含有し、前記フマル酸エステルの重合単位のエステル部は80~100%がイソプロピルエステルであり、
前記積層フィルムについて波長450nmの光で測定した面外位相差Rth450と、波長550nmの光で測定した面外位相差Rth550との比の値Rth450/Rth550が1.1~1.9の範囲内にある積層フィルム。 - 前記積層フィルムについて波長550nmの光で測定した面外位相差Rth550が、-30~-15nmの範囲内にある請求項1に記載の積層フィルム。
- 請求項1又は請求項2に記載の積層フィルムと偏光子が積層されてなる偏光板。
- 請求項3に記載の偏光板を具備した液晶表示装置。
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US20010050729A1 (en) * | 1997-06-14 | 2001-12-13 | Yong Beom Kim | Reflective-type liquid crystal display device and method of manufacturing thereof |
JP2006257380A (ja) * | 2005-02-18 | 2006-09-28 | Fuji Photo Film Co Ltd | セルロースエステルフィルムの製造方法、セルロースエステルフィルム、偏光板及び液晶表示装置 |
JP2007051210A (ja) * | 2005-08-17 | 2007-03-01 | Fujifilm Corp | 光学フィルム、その製造方法、これを用いた光学補償フィルム、偏光板および液晶表示装置 |
JP2008112141A (ja) * | 2006-10-04 | 2008-05-15 | Tosoh Corp | 光学フィルム |
JP2009037110A (ja) * | 2007-08-03 | 2009-02-19 | Tosoh Corp | 光学補償フィルム |
JP2010077318A (ja) * | 2008-09-26 | 2010-04-08 | Fujifilm Corp | セルロースエステルフィルム、それを含む偏光板及び液晶表示装置 |
JP2012132945A (ja) * | 2010-12-17 | 2012-07-12 | Tosoh Corp | 光学薄膜 |
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JPS5245109B2 (ja) | 1974-06-14 | 1977-11-12 |
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Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
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US20010050729A1 (en) * | 1997-06-14 | 2001-12-13 | Yong Beom Kim | Reflective-type liquid crystal display device and method of manufacturing thereof |
JP2006257380A (ja) * | 2005-02-18 | 2006-09-28 | Fuji Photo Film Co Ltd | セルロースエステルフィルムの製造方法、セルロースエステルフィルム、偏光板及び液晶表示装置 |
JP2007051210A (ja) * | 2005-08-17 | 2007-03-01 | Fujifilm Corp | 光学フィルム、その製造方法、これを用いた光学補償フィルム、偏光板および液晶表示装置 |
JP2008112141A (ja) * | 2006-10-04 | 2008-05-15 | Tosoh Corp | 光学フィルム |
JP2009037110A (ja) * | 2007-08-03 | 2009-02-19 | Tosoh Corp | 光学補償フィルム |
JP2010077318A (ja) * | 2008-09-26 | 2010-04-08 | Fujifilm Corp | セルロースエステルフィルム、それを含む偏光板及び液晶表示装置 |
JP2012132945A (ja) * | 2010-12-17 | 2012-07-12 | Tosoh Corp | 光学薄膜 |
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