Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
  • C08J5/18—Manufacture of films or sheets
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
  • B29D7/00—Producing flat articles, e.g. films or sheets
  • B29D7/01—Films or sheets
• • 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
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
  • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
  • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
  • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
  • G02F1/1333—Constructional arrangements; Manufacturing methods
  • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
  • G02F1/13363—Birefringent elements, e.g. for optical compensation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2001/00—Use of cellulose, modified cellulose or cellulose derivatives, e.g. viscose, as moulding material
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2995/00—Properties of moulding materials, reinforcements, fillers, preformed parts or moulds
  • B29K2995/0018—Properties of moulding materials, reinforcements, fillers, preformed parts or moulds having particular optical properties, e.g. fluorescent or phosphorescent
  • B29K2995/0034—Polarising
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
  • B29L2007/00—Flat articles, e.g. films or sheets
  • B29L2007/002—Panels; Plates; Sheets
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2301/00—Characterised by the use of cellulose, modified cellulose or cellulose derivatives
  • C08J2301/08—Cellulose derivatives
  • C08J2301/10—Esters of organic acids

Definitions

• the present invention relates to a cellulose acylate film having a negative letter direction in the film thickness direction.
• the present invention relates to a retardation plate, a polarizing plate and a liquid crystal display device using the same.
• Cellulose ester films are used in supports for halogenated photographic light-sensitive materials, retardation plates, supports for retardation plates, protective films for polarizing plates, and liquid crystal display devices.
• the cellulose acetate film that is most commonly used for optical applications such as image display devices mainly employs the solution casting film forming method. It is manufactured.
• the film thickness direction letter retardation (Rth) is usually a positive value.
• the Rth is lowered by simultaneously increasing the degree of acetylation, and at the same time the solubility in organic solvents is lowered. Therefore, Rth is expected to be negative in a cellulose acetate film with a very high degree of acetylation, but it can be sufficiently dissolved even after stirring at a temperature close to room temperature after swelling in a halogenated organic solvent. It was not possible to form a film for optical use having an excellent surface shape.
• Non-Patent Document 1 and Patent Document 1 show that the solubility in a solvent can be improved by using cellulose acetate as a mixed fatty acid ester.
• this film When a cellulose ester film having a negative Rth is produced, this film can be used as it is as a retardation plate for an IPS mode liquid crystal display device to improve the visibility of the panel, or a cellulose ester film having a positive Rth can be applied. By combining them, it is possible to manufacture a retardation plate with Rth adjusted freely, which is generally not easily controlled. Therefore, it is anxious to produce a cellulose ester film having a negative Rth. Although a film having a negative Rth can be produced by a complicated method as disclosed in Patent Document 2, the productivity is insufficient.
• Patent Document 1 JP-A-8-231761
• Patent Document 2 JP 2000-231016
• Non-patent literature l Ind. Eng. Chem., 43 ⁇ , p. 688, 1951
• a cellulose ester film When a cellulose ester film is used for an optical application such as a retardation plate, a support for a retardation plate, a protective film for a polarizing plate, or a liquid crystal display device, the optical anisotropy is extremely controlled. is important.
• Cellulose ester films are generally considered to be difficult to control in-plane letter retardation (Re), and in the thickness direction letter retardation (Rth) is difficult.
• Re in-plane letter retardation
• Rth thickness direction letter retardation
• the cell mouth ester film is manufactured so that the thickness direction retardation becomes a low value. It was very difficult.
• An object of the present invention is to provide a transparent cellulose acylate film having a negative letter value in the film thickness direction at an industrially low cost, which is provided with a retardation plate or a retardation plate support, It is to be used as a protective film for a polarizing plate to provide an excellent liquid crystal display device.
• the present invention provides the following cellulose acylate films (1) to (5), retardation plates (6) and (7) below, polarizing plates (8) below and (9) to (13) below. ) Of cellulose acylate film is provided.
• SA and SP represent the degree of substitution of the acyl group substituted with the hydroxyl group of cellulose
• SA is the degree of substitution of the acetyl group
• SP is the degree of substitution of the propiol group.
• the above-mentioned characteristic is that the change with humidity between the letter-thickness value in the film thickness direction at 25 ° C and 10% RH and the letter-value value in the film thickness direction at 25 ° C80% RH is 15 nm or less ( The cellulose acylate film according to any one of 1) to (3).
• a phase difference plate comprising at least one cellulose acylate film according to any one of (1) to (5) above.
• SA and SP represent the degree of substitution of the acyl group substituted with the hydroxyl group of cellulose
• SA is the degree of substitution of the acetyl group
• SP is the degree of substitution of the propiol group.
• Pulp-derived cellulose ester in which the degree of acyl substitution to the hydroxyl group of cellulose satisfies all of the following formulas (A) to (C):
• An organic solvent having a boiling point of 80 ° C or lower at 10 to 35 ° C It is obtained by subjecting the mixture to swelling in a solvent containing it, dissolving the mixture at 0.2 to 30 MPa at 40 to 150 ° C under high pressure and high temperature, and cooling the heated mixture to 0 to 35 ° C, followed by filtration.
• a method for producing a cellulose acylate film characterized by casting from a solution
• SA and SP represent the degree of substitution of the acyl group substituted with the hydroxyl group of cellulose
• SA is the degree of substitution of the acetyl group
• SP is the degree of substitution of the propiol group.
• the cellulose ester film has a letter value of 25 ° C., 60% RH after conditioning for 24 hours, and then using an automatic birefringence meter (for example, ABR-10A manufactured by Youbut Co., Ltd.), 25 At 60 ° RH and 60 ° RH, the direction force perpendicular to the sample film surface and the direction force inclined by ⁇ 40 ° from the normal to the film surface was measured.
• nx is the refractive index in the slow axis (x) direction in the film plane
• ny is the refractive index in the fast axis (y) direction in the film plane
• nz Is the refractive index in the film thickness direction (direction perpendicular to the film surface)
• d is the film thickness (nm).
• the slow axis is the direction in which the refractive index is maximum in the film plane
• the fast axis is the direction in which the refractive index is minimum in the film plane.
• the change of the letter value with humidity was calculated by adjusting the film's humidity at 25 ° C and 10% RH and measuring the force Re, 13 ⁇ 411 (1 ⁇ (10%), Rth (10 %)), And Re calculated by measuring the pressure after conditioning at 25 ° C and 80% RH, 13 ⁇ 411 (indicated as 1 ⁇ (80%) and Rth (80%) respectively) From the above, the humidity dependence of Re ( ⁇ Re) and the humidity dependence of Rth ( ⁇ Rth) represented by the following formulas (3) and (4) are calculated.
• the haze of the cellulose ester film is adjusted to JIS K-6714 using a haze meter (HGM-2DP: manufactured by Suga Test Instruments Co., Ltd.) after conditioning the film for 24 hours at 25 ° C and 60% RH. Measured accordingly.
• HGM-2DP manufactured by Suga Test Instruments Co., Ltd.
• a feature of the present invention is that a cellulose ester film having a negative Rth value can be obtained.
• a cellulose ester film having an Rth in the range of -400 to 15 nm, particularly from 200 to 120 nm, more preferably from 150 to 30 nm, can be obtained, which is preferable for application to various optical finems.
• Rth has a humidity dependency of 2 Onm or less, especially 18 nm or less, and even 15 nm or less.
• the thickness direction letter-thickness (Rth) of the cellulose ester film by adjusting the manufacturing process conditions such as stretching, but the cellulose ester film of the present invention has a very low Rth.
• IPS (In-Plane Switching) mode liquid crystal display device It can be used as a phase difference plate.
• Rth can be easily controlled by bonding a cellulose ester film of which Rth has a positive value, which has been known in the past, and the cellulose ester film of the present invention.
• a cellulose ester film having a negative Rth a transparent and low haze can be obtained.
• cellulose acetate propionate and cellulose propionate with high substitution which is expected to have a large Rth reduction effect
• the cellulose ester film of the present invention can increase the amount of the high boiling point solvent more than usual and increase the cooling rate, whitening can be suppressed.
• the smaller the haze of the film the more preferably 0.6% or less, more preferably 0.5% or less, and even more preferably 0.3% or less.
• Such a low haze is achieved by the cellulose ester film of the present invention. Can be reached.
• a polycarbonate film produced by a complicated method is well known as a polymer film having a negative Rth value.
• the productivity is sufficient and the traction force is different between the polycarbonate film and the cellulose ester film in physical properties such as expansion coefficient, optical properties such as refractive index, and moisture permeability coefficient.
• the cellulose acetate film of the present invention is a cellulose ester compound derived from wood pulp-derived cellulose, and ester-substituted obtained by introducing biological groups or chemical functional groups from cellulose derived from pulp.
• a film comprising a compound having a cellulose skeleton.
• the acid constituting the ester is acetic acid and Z or propionic acid which are carboxylic acids having 2 and Z or 3 carbon atoms.
• Cellulose acylate composed of carboxylic acid having 4 or more carbon atoms is flexible in the side chain, so the side chain lies in the plane due to the compressive force during film formation and acts to increase Rth. Therefore, a cellulose acylate film having a large negative value in the film thickness direction cannot be produced.
• the cellulose acylate of the invention is a cellulose acylate derived from wood pulp.
• the wood pulp may be derived from coniferous trees or from broadleaf cocoons.
• cellulose acylate synthesis method The basic principle of the cellulose acylate synthesis method is described in Nobuhiko Umeda et al., Wood Chemistry, 180-190 (Kyoritsu Shuppan, 1968).
• a typical method for synthesizing cellulose acylate is a liquid phase acylation method using a carboxylic acid anhydride, rubonic acid and sulfuric acid catalyst. Specifically, the cellulose raw material of wood pulp is pretreated with a suitable amount of rubonic acid such as acetic acid, and then poured into a pre-cooled mixture of acylic acid and esterified to obtain a complete cellulose acylate (2nd, The total power of the 3rd and 6th positions of the acyl substitution is approximately 3.00).
• the acylic acid mixture generally contains a carboxylic acid as a solvent, a carboxylic acid anhydride as an esterifying agent, and sulfuric acid as a catalyst.
• Carboxylic anhydride is usually used in a stoichiometric excess over the sum of the cellulose that reacts with it and the water present in the system.
• acylation reaction water or hydrous acetic acid is added to hydrolyze the excess carboxylic anhydride remaining in the system.
• a neutralizing agent for example, calcium, magnesium, iron, aluminum or zinc carbonate, acetate, hydroxide or oxide
• the obtained complete cellulose acylate is ripened in the presence of a small amount of an acyl reaction catalyst (generally, remaining sulfuric acid) at 20 to 90 ° C. to obtain the desired degree of acyl substitution.
• acyl reaction catalyst generally, remaining sulfuric acid
• the desired cellulose acylate was obtained At this point, the catalyst remaining in the system is completely neutralized with the neutralizing agent as described above, or the cellulose acylate solution is put into water or dilute acetic acid without neutralization ( Alternatively, water or dilute acetic acid is added to the cellulose acylate solution) to separate the cellulose acylate, and the cellulose acylate is obtained by washing and stabilizing treatment.
• the degree of polymerization of cellulose acylate is preferably 200 to 400, more preferably 220 to 350, with a viscosity average degree of polymerization of preferably 150 to 500.
• the viscosity average degree of polymerization can be measured according to Uda et al.'S limit viscosity method (Kazuo Uda, Hideo Saito, Journal of Textile Science, 18th No. 1, pages 105-120, 1962). A method for measuring the viscosity average degree of polymerization is also described in JP-A-9 95538.
• Cellulose acylate has a high average molecular weight (degree of polymerization), but its viscosity is lower than that of ordinary cellulose acylate.
• Cellulose silicate with a small amount of low molecular components can be obtained by removing low molecular components from cellulose silicate synthesized by a conventional method. The removal of low molecular components can be performed by washing the cellulose acylate with an appropriate organic solvent. It is also possible to synthesize cellulose acylate with low molecular components.
• the amount of sulfuric acid catalyst in the acylation reaction is preferably adjusted to 0.5 to 25 parts by mass with respect to 100 parts by mass of cellulose.
• the amount of the sulfuric acid catalyst is within the above range, cellulose acylate (which has a uniform molecular weight distribution) can be synthesized from the viewpoint of molecular weight distribution.
• the polymer component constituting the film is preferably substantially composed of cellulose silicate. “Substantially” means 55% by mass or more (preferably 70% by mass or more, more preferably 80% by mass or more) of the polymer component. Cell mouth Two or more types of cellulose acylate may be used in combination with one succinate film.
• cellulose acylate particles as a raw material of the cellulose ester solution. 90% by mass or more of the particles used preferably have a particle size of 0.2 to 5 mm. In addition, 50% by mass or more of the particles used have a particle diameter of 0.4 to 4 mm. It is preferable to do.
• the cellulose acylate particles preferably have a shape as close to a sphere as possible.
• the cellulose acylate used for the preparation of the cellulose ester solution preferably has a moisture content of 1.5% by mass or less, more preferably 1% by mass or less, and 0.7% by mass. Most preferably: Cellulose ⁇ Shi rate is generally 1 has a 8-5 mass 0/0 moisture content of. Therefore, it is preferable to dry the cellulose acylate and use it.
• various additives for example, plasticizers, modifiers, ultraviolet inhibitors, optical anisotropy control agents, fine particles, release agents, Infrared absorber
• plasticizer is described in JP-A-2001-151901.
• infrared absorber is described in JP-A-2001-194522.
• the timing for adding the additive is determined according to the type of the additive.
• the types and amounts of additives in each layer may be different (for example, described in JP-A-2001-151902).
• the main solvent of the cellulose ester solution is that an organic solvent having a boiling point of 80 ° C or less also has a favorable viewpoint power for reducing a drying load.
• a boiling point of 10 to 80 ° C is more preferable. More preferably, the boiling point is preferably 30 to 45 ° C, more preferably 60 ° C.
• Examples of such a main solvent include halogenated hydrocarbons, esters, ketones, ethers, alcohols and hydrocarbons, which may have a branched structure or a cyclic structure. Further, it may have any two or more functional groups of esters, ketones, ethers and alcohols (that is, —O—, 1 CO—, 1 COO—, 1 OH).
• the hydrogen atom in the hydrocarbon portion of ester, ketone, ether and alcohol may be substituted with a halogen atom (particularly a fluorine atom).
• the main solvent of the cellulose ester solution indicates the solvent when it has a single solvent power, and when it consists of a plurality of solvents, it has the highest weight fraction among the constituent solvents. Indicates a solvent.
• halogenated hydrocarbon dichloromethane and chlorinated hydrocarbon are more preferable. Examples thereof include dichloromethane, and dichloromethane is more preferable.
• ester examples include methyl formate, ethyl formate, methyl acetate, ethyl acetate and the like.
• ketones include acetone and methyl ethyl ketone.
• ethers examples include jetyl ether, methyl t-butyl ether, diisopropyl ether, dimethoxymethane, 1,3 dioxolane, 4-methyl dioxolane, tetrahydrofuran, and methinoretetrahydrofuran.
• alcohol examples include methanol, ethanol, and 2-propanol.
• hydrocarbon examples include n-pentane, cyclohexane, n-hexane, and benzene.
• organic solvent used in combination with these include halogenated hydrocarbons, esters, ketones, ethers, alcohols, and hydrocarbons, and they may have a branched structure or a cyclic structure. Further, it may have two or more functional groups of esters, ketones, ethers and alcohols (that is, —O—, —CO—, —COO, 1OH). Furthermore, the hydrogen atom in the hydrocarbon portion of the ester, ketone, ether and alcohol may be substituted with a halogen atom (particularly a fluorine atom).
• halogenated hydrocarbon examples include dichloromethane and chloroform, which are more preferable to chlorinated hydrocarbon, and dichloromethane is more preferable.
• ester examples include methyl formate, ethyl formate, propyl formate, pentyl formate, methyl acetate, ethyl acetate, and pentyl acetate.
• ketone examples include acetone, methyl ethyl ketone, jetyl ketone, diisoptyl ketone, cyclopentanone, cyclohexanone, and methylcyclohexanone.
• ethers include jetyl ether, methyl-butyl ether, diisopropyl ether, dimethoxymethane, dimethoxyethane, 1,4 dioxane, 1,3 dioxolan, 4-methyldioxolan, tetrahydrofuran, methyltetrahydrofuran, anisole, phenetole, etc. Is mentioned.
• Alcohols include methanol, ethanol, 1 propanol, 2-propanol, 1-butanol, 2-butanol, t-butanol, 1 pentanol, 2-methyl-2-butanol, cyclohexanol, 2-fluoroethanol, 2, 2, 2-trifluoroethanol, 2, 2, 3, 3-tetra And fluoro-1-propanol.
• hydrocarbon examples include n-pentane, cyclohexane, n-hexane, benzene, toluene, xylene and the like.
• organic solvent having two or more types of functional groups examples include 2-ethoxyethyl acetate, 2-methoxyethanol, 2-butoxyethanol, and methylacetoacetate.
• an organic solvent having a boiling point of 95 ° C or higher should be contained in the total amount of at least 5 to 15% by mass, more preferably 6 to 13% by mass, and even more preferably 7 to 12% by mass.
• the viewpoint power of suppressing film whitening during the drying process is also preferable.
• the amount of the high boiling point solvent is more than 15% by mass, the drying load becomes large, and there is a risk that productivity is lowered from the viewpoint of energy efficiency in production.
• the peeling load at the time of peeling from the band surface is light compared to the conventional cellulose ester, but in order to obtain a more preferable peeling load,
• the solvent preferably contains 5 to 30% by mass of alcohol, more preferably 6 to 20% by mass, and even more preferably 7 to 15% by mass.
• the organic solvent having a boiling point of 95 ° C. or higher is preferably alcohol from the viewpoints of reducing the peeling load from the band and suppressing film whitening.
• the concentration of the cellulose ester solution to be prepared is preferably 10 to 40% by mass.
• 35 to 30% by weight is more preferred 15 to 30% by weight is most preferred.
• the cellulose ester can be adjusted to a predetermined concentration at the stage of dissolution in a solvent.
• this method in which a solution having a low concentration (for example, 9 to 14% by mass) is prepared in advance and then concentrated, is relatively poor in solubility and is particularly effective when a cellulose ester is used.
• a high concentration solution may be diluted after preparation. By adding an additive, the concentration of cellulose ester can be reduced.
• the cellulose ester solution may contain various liquid or solid additives.
• the additive examples include a plasticizer (preferable amount of addition force is 0.1 to 20% by mass based on the cellulose ester, the same applies hereinafter), a modifier (0.1 to 20% by mass), an ultraviolet absorber ( 0.001 to 5% by mass), fine particle powder (0.001 to 5% by mass) having an average particle diameter of 5 to 3000 nm, fluorine-based surfactant (0.001 to 2% by mass), release agent (0 0001 to 2% by mass), deterioration inhibitor (0.001 to 2% by mass), optical anisotropy control agent (0.1 to 15% by mass), infrared absorber (0.1 to 5% by mass) It may be included.
• a plasticizer preferable amount of addition force is 0.1 to 20% by mass based on the cellulose ester, the same applies hereinafter
• a modifier 0.1 to 20% by mass
• an ultraviolet absorber 0.001 to 5% by mass
• fine particle powder 0.001 to 5% by mass having an average particle diameter of 5 to 3000 nm
• the cellulose ester solution preferably has a viscosity of 1 to 400 Pa's at 30 ° C, more preferably 10 to 200 Pa's! /.
• Viscosity and dynamic storage modulus are measured using a rheometer (CLS500, TA Instruments) by placing 1 mL of the sample solution in a container (STEEL CONE, TA Instruments) with a diameter of 4 cm and a cone angle of 2 °. . Measurement conditions were measured using conditions (Oscillation Step / Temperature Ramp) attached to the apparatus. Measurement is started after the sample solution is kept warm at the measurement start temperature until the liquid temperature becomes constant.
• the cellulose ester film can be produced by using a conventional solution casting film forming apparatus in accordance with a conventional solution casting film forming method.
• the dope (cellulose ester solution) prepared in the dissolving machine (kettle) is filtered and stored in a storage kettle, and the foam contained in the dope is defoamed for final preparation.
• the dope is kept at 30 ° C and sent from the dope discharge port to the pressure die through a pressure metering gear pump that can deliver a fixed amount of liquid with high accuracy, for example, by the number of rotations. It is cast evenly on the metal support of the cast part, and the dry dry dope film (web and Is also peeled from the metal support.
• two or more types of cellulose ester solutions may be cast simultaneously or sequentially.
• Two or more types of cellulose ester solutions may have exactly the same composition. If the composition is different, the type of solvent or additive can be changed from solution to solution. Two or more types of solutions may have different concentrations. Two or more types of solutions may have different molecular weights of cellulose ester aggregates. Two or more solutions may be held at different temperatures.
• the method of containing an organic solvent which is a poor solvent for cellulose ester having a high boiling point as described above is effective, and when the film is cooled after drying is completed, the film temperature is the glass transition temperature (Tg). It is effective to cool rapidly from a state where the main chain spacing is wide and to quench with the main chain spacing wide.
• the residual solvent in the film thus dried is preferably 0 to 5% by mass, more preferably 0 to 2% by mass, and still more preferably 0 to 1% by mass. After drying, trim and wind up both ends.
• the preferred width is 0.5 to 5 m, more preferably 0.7 to 3 m, and even more preferably 1 to 2 m.
• the preferred saddle length is 300 to 30000 m, more preferably 500 to: LOOOOm, more preferably ⁇ 1000 to 7000 m.
• the cellulose acylate film can be stretched. Stretching may be performed in an undried state during film formation (for example, after the casting, after peeling off from the support until the completion of drying) or after completion of drying. These stretches are film forming During the process, it may be performed on-line. After film formation is completed, the film may be wound once and then off-line.
• the stretching is preferably performed at Tg or more and Tg + 50 ° C or less, more preferably Tg + c or more and Tg + 30 ° C or less, and further preferably Tg + 2 ° C or more and Tg + 20 ° C or less.
• the draw ratio is preferably 1% to 500%, more preferably 3% to 400%, and still more preferably 5% to 300%.
• Stretch ratio (%) 100X ⁇ (Length after stretching)-(Length before stretching) ⁇ Z Length before stretching
• the film may be stretched in the longitudinal direction (longitudinal stretching), or both ends of the film may be held by a chuck and spread in the orthogonal direction (perpendicular to the longitudinal direction) (lateral stretching).
• Rth can be increased by increasing the draw ratio.
• Re can be increased by increasing the difference between the ratios of longitudinal stretching and lateral stretching.
• the ratio of Re and Rth can be freely controlled by controlling the value (aspect ratio) obtained by dividing the space between the rolls by the film width in the case of longitudinal stretching.
• the RthZRe ratio can be increased by reducing the aspect ratio.
• transverse stretching it can be controlled by stretching in the orthogonal direction and simultaneously stretching in the longitudinal direction, or conversely relaxing. That is, the RthZRe ratio can be increased by stretching in the vertical direction, and the RthZRe ratio can be decreased by relaxing in the vertical direction.
• Such a stretching speed is preferably 10 to: LOOOO% Z, more preferably 20 to: LOOO% Z, and further preferably 30 to 800% Z.
• the angle ⁇ between the film forming direction (longitudinal direction) and the Re slow axis of the film is 0 ⁇ 3 °, +9 0 ⁇ 3 ° or -90 ⁇ 3 ° 0 ⁇ 2 More preferably, it is 0 ⁇ 1 °, + 90 ⁇ 1 ° or ⁇ 90 ⁇ 1 °, more preferably + 90 ⁇ 2 ° or 90 ⁇ 2 °.
• the cellulose acylate film of the present invention preferably has a film thickness of 60 to 180 ⁇ m or less, more preferably 60 to 150 m force, and even more preferably 65 to 120 ⁇ m force.
• the film thickness is less than 60 ⁇ m, the handling property and the curling of the polarizing plate are not preferable when processing into a polarizing plate. If it is thicker than ⁇ m, it takes a long time to dry to a volatile content that can be stripped off. Unevenness of film thickness
• 0 to 2% is preferable, more preferably 0 to 1.5%, and still more preferably 0 to 1%.
• the cellulose acylate film after being stretched and stretched according to the present invention is appropriately subjected to a surface treatment, whereby the cellulose acylate film and each functional layer (for example, an undercoat layer or a back layer). It becomes possible to improve the adhesion.
• Surface treatment includes glow discharge treatment, ultraviolet irradiation treatment, corona treatment, flame treatment, saponification treatment (acid saponification treatment, alkali saponification treatment). preferable.
• Glow one discharge treatment including low-temperature plasma treatment carried out under a low gas pressure of 10 one 3 ⁇ 20 Torr.
• Plasma treatment under atmospheric pressure is also a preferable glow discharge treatment.
• the plasma exciting gas argon, helium, neon, krypton, xenon, nitrogen, carbon dioxide, chlorofluorocarbon (eg, tetrafluoromethane) and a mixture thereof are used.
• the plasma treatment at atmospheric pressure is preferably carried out at 10 to: LOOOkeV, more preferably 30 to 500 keV.
• the irradiation energy is preferably 20 to 500 kGy, more preferably 20 to 300 kGy.
• Glow discharge treatment is described in published technical report 2001-1745 (issued March 15, 2001, Invention Association), pages 30-32.
• the alkali saponification treatment is carried out by applying a saponification solution to the film or by immersing the film in the crystallization solution.
• the solvent of the coating solution is particularly preferably isopropyl alcohol, which alcohol is preferred.
• Water preferably an aqueous solution of a surfactant
• the alkali is preferably an alkali metal hydroxide, more preferably KOH or NaOH.
• the pH of the Ken coating solution is preferably 10 or more, more preferably 12 or more.
• the reaction conditions during alkaline cation are preferably 1 second to 5 minutes at room temperature, more preferably 5 seconds to 5 minutes, and most preferably 20 seconds to 3 minutes.
• Alkaline After the saponification reaction, it is preferable to wash the surface to which the saponification solution is applied, or after washing with an acid.
• the coating-type hatching process and the alignment film uncoating described later can be performed continuously, and the number of processes can be reduced. Specific examples of these methods are described in, for example, JP-A-2002-8 2226 and WO02Z46809.
• an undercoat layer (adhesive layer) can be provided in addition to the surface treatment or in place of the surface treatment.
• an undercoat layer published technical bulletin No. 2001-1745 (issued on March 15, 2001, Invention Association), page 32, can be used as appropriate.
• the cellulose ester film having a negative letter-thickness value in the thickness direction can be used as it is as a protective film for a retardation plate or a polarizing plate having a retardation plate function.
• a cellulose ester film having a positive thickness direction letter value By laminating with a cellulose ester film having a positive thickness direction letter value, it can be used as a retardation plate in which the thickness direction letter value is freely controlled.
• a retardation plate can be produced by using the cellulose ester film and the retardation plate as a support, and providing an optically anisotropic layer (for example, a layer formed of liquid crystalline molecules) thereon.
• the cellulose ester film is preferably subjected to alkali saponification treatment.
• an alkali cane-treated surface of a cellulose ester film can be bonded to both surfaces of the polarizing film using an adhesive.
• an aqueous solution of polybulualcohol or polybulucetal eg, polybutylbutyral
• a latex of a bull-based polymer eg, polybutyl acrylate
• the adhesive is an aqueous solution of fully saponified polyvinyl alcohol.
• an external protective film is bonded to one side of the polarizing plate and a separate film is bonded to the other side.
• the external protective film and the separate film are used for the purpose of protecting the polarizing plate in shipping of the polarizing plate and product inspection.
• the external protective film is used on the side opposite to the side where the polarizing plate is bonded to the liquid crystal cell.
• the separate film is used for the purpose of covering an adhesive layer for bonding the polarizing plate to the liquid crystal cell.
• a liquid crystal display device is provided with a liquid crystal cell between two polarizing plates.
• a liquid crystal cell is injected between two substrates. Therefore, a normal liquid crystal display device has four polarizing plate protective films.
• the cellulose ester film according to the present invention may be used for any of the four polarizing plate protective films. However, it can be used particularly advantageously as a plastic film disposed between a polarizer and a liquid crystal layer in a liquid crystal display device.
• the cellulose ester film according to the present invention, and a retardation plate and a polarizing plate using the same can be used in liquid crystal display devices of various display modes.
• liquid crystal display devices may be any of a transmissive type, a reflective type, and a transflective type.
• the alignment state in the liquid crystal cell is such that the rod-like liquid crystalline molecules rise at the center of the cell and the rod-like liquid crystalline molecules lie near the cell substrate.
• a liquid crystal display device using a bend alignment mode liquid crystal cell is disclosed in US Pat. Nos. 4,583,825 and 5,410,422. Since the rod-like liquid crystal molecules are symmetrically aligned at the top and bottom of the liquid crystal cell, The liquid crystal cell in the cell alignment mode has a self-optical compensation function. Therefore, this liquid crystal mode is also called OCB (Optically Compensatory Bend) liquid crystal mode.
• OCB Optically Compensatory Bend
• the OCB mode liquid crystal cell is in the black display, and the alignment state in the liquid crystal cell is such that the rod-like liquid crystalline molecules rise at the center of the cell and the rod-like liquid crystalline molecules lie near the cell substrate. is there.
• the rod-like liquid crystalline molecules are aligned substantially vertically when no voltage is applied.
• VA Very Aligned
• the rod-like liquid crystalline molecules are substantially aligned when no voltage is applied.
• VA mode liquid crystal cell
• VA mode is selected to expand the viewing angle.
• Multi-domain (MVA mode) liquid crystal cell SID97, Digest of tech. Papers (Preliminary report) 28 (1997) 845
• Rod-like liquid crystal molecules are aligned substantially vertically when no voltage is applied.
• Mode (n—ASM mode) liquid crystal cell (described in Proceedings 58-59 (199 8)) and (4) SURVAIVAL mode liquid crystal cell (LCD International 98) Announced).
• the characteristic is that the rod-like liquid crystalline molecules are aligned substantially in-plane horizontally when no voltage is applied, and this is the switching force S characteristic by changing the alignment direction of the liquid crystal with and without voltage application.
• JP 2004-365941, JP 2004-12731, JP 2004-215620, JP 2002-221726, JP 2002-55341, JP 2003-195333, and the like can be used.
• the ECB mode and STN mode can be compensated optically using the same concept as above.
• a cellulose ester film was conditioned at 25 ° C and 60% RH for 24 hours, and then sampled at 25 ° C and 60% RH using an automatic birefringence meter (ABR-10A: manufactured by OPT Corp.)
• the in-plane letters represented by the following formulas (1) and (2) were measured by measuring the letter value at a wavelength of 633 nm from the direction perpendicular to the film surface and the direction inclined by 40 ° from the normal to the film surface.
• the decision value (Re) and the letter decision value (Rth) in the film thickness direction were calculated.
• nx is the refractive index in the slow axis (X) direction in the film plane
• ny is the refractive index in the fast axis (y) direction in the film plane
• nz is the thickness direction of the film (film surface)
• D is the film thickness (nm).
• the slow axis is the direction in which the refractive index is maximum in the film plane
• the fast axis is the direction in which the refractive index is minimum in the film plane.
• the change of the letter value with humidity is calculated using Re and Rth (Re (10%) and Rth (10%), respectively) after the film was conditioned and measured at 25 ° C and 10% RH. And Re and Rth (represented as Re (80%) and Rth (80%), respectively) calculated by adjusting the humidity at 25 ° C and 80% RH, and calculating the following formula (3) and The humidity dependence of Re ( ⁇ Re) and the humidity dependence of Rth ( ⁇ Rth) represented by (4) are calculated.
• the cellulose ester film was conditioned at 25 ° C. and 60% RH for 24 hours, and then measured according to JIS K-6714 using a haze meter (HGM-2DP: manufactured by Suga Test Instruments Co., Ltd.).
• HGM-2DP manufactured by Suga Test Instruments Co., Ltd.
• Cellulose acylates with different types of acyl groups and different degrees of substitution described in Table 1 were prepared. Specifically, a mixture of sulfuric acid as a catalyst (7.8 parts by mass with respect to 100 parts by mass of cellulose) and carboxylic anhydride is added to cellulose derived from hardwood pulp after cooling to ⁇ 20 ° C, Acylation was carried out at 40 ° C. At this time, the kind and substitution ratio of the acyl group were adjusted by adjusting the kind and amount of the carboxylic acid anhydride. In addition, after substitution, aging was performed at 40 ° C to adjust the total substitution degree. The degree of polymerization of the cellulose acylate thus obtained was determined by the following method and listed in Table 1.
• the prepared cellulose acylate was heated to 120 ° C. and dried to reduce the water content to 0.5% by mass or less, and then 30 parts by mass was mixed with a solvent.
• the cell mouth 1 succinate was mixed with a solvent at 15 parts by mass.
• the cellulose acylate used in Comparative Example 3 was purchased from Daicel Chemical Industries, Ltd. LT 35, which was synthesized from pulp-derived cellulose.
• Solvent 6 Dichloromethane Z ethanol Z butanol (70Z10Z20 parts by mass) The water content of these solvents was 0.2% by mass or less.
• Additive 1 0.9 parts by mass of trimethylolpropane triacetate (referred to as Additive 1 in Table 1) was added.
• 0.25 mass% of dioxide fine particles 0.25 mass% of dioxide fine particles (particle size 20 nm, Mohs hardness of about 7) was added in preparing all solutions.
• the cellulose acylate was gradually added to a 400 liter stainless steel dissolution tank having a stirring blade and circulating cooling water around the outer periphery, while stirring and dispersing the solvent and additive. After completion of the addition, the mixture was stirred at room temperature for 2 hours, swollen for 3 hours, and then stirred again to obtain a cellulose acylate solution.
• an eccentric stirring shaft of a dissolver type stirring at a peripheral speed of 15 m / sec (shear stress 5 X 10 4 kgf / m / sec 2 or 4.9 X 10 5 N / mZs 2 ) and an anchor on the central axis.
• a stirring shaft having a single blade and stirring at a peripheral speed of lm / sec (shear stress 1 ⁇ 10 4 kgfZm / sec 2 or 0.98 ⁇ 10 5 N / m / s 2 ) was used. Swelling was performed with the high speed stirring shaft stopped and the peripheral speed of the stirring shaft with anchor blades set at 0.5 mZsec.
• the cellulose acylate solution obtained above was filtered with a filter paper (# 6 3. Filtration through Toyo Roshi (manufactured by Toyo Roshi Kaisha, Ltd.), followed by filtration through filter paper (FH025, Pall) with an absolute filtration accuracy of 2 gave a cellulose acylate solution.
• the cellulose acylate solution was heated to 30 ° C. and cast on a mirror surface stainless steel support with a band length of 60 m set at 15 ° C. through a casting Giesser (described in JP-A-11-314233). .
• the casting speed was 15mZ and the coating width was 200cm.
• the space temperature of the entire casting part was set to 15 ° C.
• the cellulose acylate film that had been cast and rotated 50 cm before the cast part was peeled off, and the air at 45 ° C. was blown.
• the film was cooled to room temperature in 30 seconds to obtain a cellulose acylate film.
• the obtained film was cut at 3 cm at both ends, further provided with a knurling of 125 ⁇ m in height at the edge force 2 to: LOmm, and wound into a 3000 m roll.
• the film surface condition was visually evaluated on the following scale.
• the film is completely whitened and cannot be applied as an optical film.
• the haze of the cellulose acylate film was measured by the method described above.
• the haze value is indicated by the ratio (%) of the scattered light intensity to the incident light intensity.
• Example 1 of Japanese Patent Laid-Open No. 2001-141926 a Fujitac (TD80UF, Fuji A saponified cellulose acylate film of the present invention obtained by saponifying a photographic film (Co., Ltd.) and a 3% aqueous solution of PVA (PVA-117H, Kuraray Co., Ltd.) as an adhesive was bonded to produce a polarizing plate.
• PVA PVA-117H, Kuraray Co., Ltd.
• the obtained polarizing plate was conditioned at 25 ° C and 10% RH for 24 hours, then conditioned at 25 ° C and 80% RH for 24 hours, and further conditioned at 25 ° C and 10% RH for 24 hours. Later, the curling of the polarizing plate was visually confirmed and evaluated in the following three stages.
• Table 1 The results are shown in Table 1.
• the numerical value of the amount of solvent is 100 parts by volume of the total amount of exposure goods. Part by mass.
• the column labeled “95 ° C or higher” indicates parts by mass of the solvent having a boiling point of 95 ° C or higher.
• the column labeled “alcohol” indicates the total amount of constituent alcohols constituting the solvent.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Manufacturing & Machinery (AREA)
• Materials Engineering (AREA)
• Polymers & Plastics (AREA)
• Optics & Photonics (AREA)
• Nonlinear Science (AREA)
• Mechanical Engineering (AREA)
• General Physics & Mathematics (AREA)
• Organic Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Crystallography & Structural Chemistry (AREA)
• Mathematical Physics (AREA)
• Manufacture Of Macromolecular Shaped Articles (AREA)
• Polarising Elements (AREA)
• Moulding By Coating Moulds (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Liquid Crystal (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=35776373

Family Applications (1)

Country Status (4)

Cited By (2)

Families Citing this family (8)

Citations (3)

Family Cites Families (3)

• 2004
  • 2004-06-23 JP JP2004184910A patent/JP4662738B2/ja not_active Expired - Fee Related
• 2005
  • 2005-06-21 KR KR1020067026990A patent/KR101218025B1/ko not_active Expired - Fee Related
  • 2005-06-21 WO PCT/JP2005/011383 patent/WO2006001284A1/ja not_active Ceased
  • 2005-06-21 CN CN2005800207345A patent/CN1972984B/zh not_active Expired - Fee Related

Patent Citations (3)

Also Published As

Similar Documents

Legal Events