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WO2011118145A1 - Procédé de production de film optique, film optique, plaque de polarisation et dispositif d'affichage à cristaux liquides - Google Patents

Procédé de production de film optique, film optique, plaque de polarisation et dispositif d'affichage à cristaux liquides Download PDF

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Publication number
WO2011118145A1
WO2011118145A1 PCT/JP2011/001416 JP2011001416W WO2011118145A1 WO 2011118145 A1 WO2011118145 A1 WO 2011118145A1 JP 2011001416 W JP2011001416 W JP 2011001416W WO 2011118145 A1 WO2011118145 A1 WO 2011118145A1
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WIPO (PCT)
Prior art keywords
film
stretching
optical film
stretching step
resin
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
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PCT/JP2011/001416
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English (en)
Japanese (ja)
Inventor
和義 鈴木
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Konica Minolta Opto Inc
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Konica Minolta Opto Inc
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Publication date
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Priority to JP2012506797A priority Critical patent/JPWO2011118145A1/ja
Publication of WO2011118145A1 publication Critical patent/WO2011118145A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C55/00—Shaping by stretching, e.g. drawing through a die; Apparatus therefor
    • B29C55/02—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
    • B29C55/10—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets multiaxial
    • B29C55/12—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets multiaxial biaxial
    • B29C55/14—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets multiaxial biaxial successively
    • B29C55/143—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets multiaxial biaxial successively firstly parallel to the direction of feed and then transversely thereto
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C55/00—Shaping by stretching, e.g. drawing through a die; Apparatus therefor
    • B29C55/02—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
    • B29C55/04—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets uniaxial, e.g. oblique
    • B29C55/06—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets uniaxial, e.g. oblique parallel with the direction of feed
    • B29C55/065—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets uniaxial, e.g. oblique parallel with the direction of feed in several stretching steps
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F220/10—Esters
    • C08F220/12—Esters of monohydric alcohols or phenols
    • C08F220/14—Methyl esters, e.g. methyl (meth)acrylate
    • 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
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L1/00—Compositions of cellulose, modified cellulose or cellulose derivatives
    • C08L1/08—Cellulose derivatives
    • C08L1/10—Esters of organic acids, i.e. acylates
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
    • C08L33/04—Homopolymers or copolymers of esters
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C41/00—Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor
    • B29C41/24—Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor for making articles of indefinite length
    • B29C41/26—Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor for making articles of indefinite length by depositing flowable material on a rotating drum
    • 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
    • B29K2033/00—Use of polymers of unsaturated acids or derivatives thereof as moulding material
    • B29K2033/04—Polymers of esters
    • B29K2033/08—Polymers of acrylic acid esters, e.g. PMA, i.e. polymethylacrylate
    • 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
    • B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
    • B29K2105/0088—Blends of polymers
    • 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
    • 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
    • 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
    • C08J2333/00—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Derivatives of such polymers
    • C08J2333/04—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Derivatives of such polymers esters
    • C08J2333/06—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Derivatives of such polymers esters of esters containing only carbon, hydrogen, and oxygen, the oxygen atom being present only as part of the carboxyl radical
    • 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

Definitions

  • the present invention relates to an optical film manufacturing method, an optical film obtained by the optical film manufacturing method, a polarizing plate using the optical film as a transparent protective film, and a liquid crystal display device including the polarizing plate.
  • the solution casting film forming method is a method in which a resin solution (dope) in which a transparent resin as a raw material resin is dissolved in a solvent is cast on a traveling support and dried to a peelable extent.
  • a long resin film is produced by peeling the film obtained from the support from the support, and performing drying, stretching and the like while carrying the peeled film with a carrying roller.
  • liquid crystal display devices are diversifying, and not only indoor use but also outdoor use is increasing. Specifically, for example, by displaying video and information on a liquid crystal display device, it works as an advertising medium instead of a poster or the like, that is, when used as a digital signage device, or a large display device on a street or store The case where it installs and uses as is mentioned.
  • the liquid crystal display device may be used, for example, under high temperature and high humidity, and the deterioration of the optical film due to moisture absorption may be a problem. Therefore, the optical film used is required to have high moisture resistance that can suppress deterioration due to moisture absorption.
  • acrylic resins such as polymethyl methacrylate resin (PMMA), which is known as an optical material with low hygroscopicity, have low hygroscopicity and are excellent in transparency and dimensional stability.
  • PMMA polymethyl methacrylate resin
  • an acrylic film containing an acrylic resin has a property of being easily broken and brittle when compared with a cellulose ester film or the like. For this reason, it is difficult to handle, and in particular, it has been difficult to stably manufacture an optical film for a liquid crystal display device having a large screen. Specifically, for example, there is a case where a problem such as cracking occurs when the end of the film is cut.
  • Patent Document 1 describes a retardation film mainly composed of an acrylic polymer and having a predetermined in-plane retardation value and total light transmittance.
  • Patent Document 1 it is disclosed that a retardation film having transparency, heat resistance, and high retardation performance can be provided.
  • Patent Document 2 describes an optical film containing an acrylic resin and a cellulose ester resin.
  • Patent Document 2 discloses that an optical film having low hygroscopicity, transparency, high heat resistance, and markedly improved brittleness can be provided. That is, by including a cellulose ester resin in an acrylic resin, the brittleness is improved, and the obtained optical film can be suitably used as a protective film for a polarizing plate for a liquid crystal display device.
  • Patent Document 3 As a conventional technique for facilitating the handling of the optical film, for example, the one described in Patent Document 3 can be mentioned.
  • Patent Document 3 in the solution casting film forming method using an endless belt support, the residual solvent amount of the film until the film peeled from the endless belt support is stretched is measured from the end of the film to the center. A method for producing an optical film that is higher is described.
  • Patent Document 3 in the solution casting film forming method using an endless belt support, the elastic modulus is improved without being limited to a specific raw material by adjusting the residual solvent amount of the film during stretching or the like.
  • a wide-width, thin-film optical film that maintains strength and is easy to handle can be manufactured.
  • JP 2008-9378 A International Publication No. 2009/47924 JP 2008-200909 A
  • the present invention is an optical film capable of producing an optical film excellent in transparency, workability and flatness even when an acrylic resin is contained in a cellulose ester resin in order to improve moisture resistance, heat resistance, and the like. It aims at providing the manufacturing method of. Another object of the present invention is to provide an optical film obtained by the method for producing an optical film, a polarizing plate using the optical film as a transparent protective film, and a liquid crystal display device including the polarizing plate.
  • One aspect of the present invention is to cast a resin solution containing an acrylic resin and a cellulose ester resin at a mass ratio of 95: 5 to 30:70 onto a traveling support to form a cast film.
  • a casting process a peeling process for peeling the cast film from the support as a film, a first stretching process for stretching the peeled film in the transport direction while transporting the peeled film, and the first stretching process.
  • a second stretching step for stretching in a direction perpendicular to the transport direction of the film while transporting the film stretched by the step, and a direction perpendicular to the transport direction of the film while transporting the film stretched by the second stretching step.
  • the total of the stretch ratio of the film in the first stretching step and the stretch ratio of the film in the third stretching step is that of the acrylic resin with respect to the total amount of the acrylic resin and the cellulose ester resin.
  • the content rate is A mass%, it is in the range of A / 3 + 10 to A / 5 + 40 in terms of percentage, and the stretch ratio of the film in the first stretching step is the same as the stretch ratio of the film in the first stretching step.
  • the method for producing an optical film is characterized by being 70 to 95% with respect to the total of the stretching ratio of the film in the third stretching step.
  • another aspect of the present invention is an optical film obtained by the method for producing an optical film.
  • a polarizing plate including a polarizing element and a transparent protective film disposed on at least one surface of the polarizing element, wherein the transparent protective film is the optical film. It is a polarizing plate characterized by being.
  • Another aspect of the present invention is a liquid crystal display device including a liquid crystal cell and two polarizing plates arranged so as to sandwich the liquid crystal cell, and at least one of the two polarizing plates.
  • a liquid crystal display device characterized by being the polarizing plate.
  • an acrylic film containing an acrylic resin as described in Patent Document 1 has a property of being easily broken and brittle when compared with a cellulose ester film or the like. Therefore, there are cases where problems relating to workability such as low cutting properties such as cracking when the film ends are cut during film production may occur.
  • the optical film described in Patent Document 2 is preferably used as a protective film for a polarizing plate for a liquid crystal display device having a large screen, depending on the production method and the like. There was a case that could not be. Specifically, depending on the production method, transparency such as haze may be lowered, processability such as cutting property may not be sufficiently improved, or planarity may be reduced. .
  • the manufacturing method of the optical film of patent document 3 can manufacture suitably the cellulose-ester film used as an optical film, such a manufacturing method is used for acrylic resin. Even if it applies to the manufacturing method of the resin film to contain, generation
  • the present inventor when manufacturing a film containing an acrylic resin or acrylic particles in addition to a cellulose ester resin, instead of a film made of a cellulose ester resin, it was inferred that the occurrence of problems such as cracking when the part was cut was affected by stretching when manufacturing the optical film.
  • a resin solution containing an acrylic resin and a cellulose ester resin in a mass ratio of 95: 5 to 30:70 is cast on a traveling support.
  • a first stretching step, a second stretching step of stretching the film stretched in the first stretching step in a direction perpendicular to the transport direction of the film (Transverse Direction: TD direction), and the second While conveying the film stretched by the stretching process, both ends in the direction (width direction) perpendicular to the film transport direction are And a third stretching step for stretching in the transport direction (MD direction) of the film while transporting the film from which the trimmed end portions have been removed.
  • it is performed by an optical film manufacturing apparatus using a solution casting film forming method as shown in FIG.
  • an optical film manufacturing apparatus it is not limited to what is shown in FIG. 1, The thing of another structure may be sufficient.
  • the film is a film after a cast film (web) made of a resin solution (dope) cast on the support is dried on the support and can be peeled off from the support.
  • the optical film refers to a film finally obtained by the optical film manufacturing method according to the present embodiment.
  • the total stretch ratio of the acrylic resin is A mass% with respect to the total amount of the acrylic resin and the cellulose ester resin, it is in the range of A / 3 + 10 to A / 5 + 40 in percentage. And preferably within a range of A / 3 + 15 to A / 5 + 30.
  • A is 70% by mass, and the first stretch ratio and the third stretch ratio. Is about 33-54%, preferably about 38-44%.
  • the strength of a film can be improved, suppressing generation
  • the first stretching ratio is 70 to 95%, preferably 80 to 95%, based on the total stretching ratio in the transport direction (MD direction) of the film. If the first stretching ratio is too low, the third stretching ratio becomes too high, and wrinkles (vertical wrinkles) extending in the film transport direction (longitudinal direction) tend to be formed during the third stretching step. This is probably because of this. On the other hand, if the first stretching ratio is too high, the third stretching ratio becomes too low, and wrinkles (lateral direction) extending in the direction (short direction) perpendicular to the film transport direction formed in the second stretching step. It is considered that wrinkles) tend not to be sufficiently removed even if they are stretched in the transport direction in the third stretching step. Therefore, it is considered that when the first stretching ratio is within the above range, the planarity can be improved while improving the transparency and workability of the obtained film.
  • stretch ratio (first stretch ratio) of the film in the first stretching process and the stretch ratio (third stretch ratio) of the film in the third stretching process are determined as follows.
  • the film transport speed in the first stretching step and the third stretching step is measured.
  • the draw ratio (MD draw ratio) of MD direction which is said 1st draw ratio and said 3rd draw ratio is computed by following formula (1) using the conveyance speed of the film in each obtained process.
  • MD stretch rate (%) ⁇ (film transport speed in each step ⁇ casting speed) / casting speed ⁇ ⁇ 100 (1)
  • the casting speed is the traveling speed (circumferential speed) of the endless drum support 12.
  • stretching ratio change also with a composition of a film, a residual solvent rate of a film, etc., according to the conveyance tension of a film, the atmospheric temperature in each process, the roller temperature in each process, etc. Can be adjusted.
  • FIG. 1 is a schematic diagram showing a basic configuration of an optical film manufacturing apparatus 11 based on a solution casting film forming method according to an embodiment of the present invention.
  • the optical film manufacturing apparatus 11 includes an endless drum support 12, a casting die 13, a peeling roller 14, a first stretching device 15, a second stretching device 16, a cutting device 17, a third stretching device 18, and a winding device 20. Etc.
  • the casting die 13 casts a resin solution (dope) 19 obtained by dissolving a cellulose ester resin and an acrylic resin, which will be described later, on the surface of the endless drum support 12.
  • the endless drum support 12 is supported so as to be rotationally driven, and a web made of the dope 19 cast from the casting die 13 is formed on the surface thereof. Then, the web is dried while being transported by the rotation of the endless drum support 12. By doing so, the said web is made into the film which can peel from the said endless drum support body 12. As shown in FIG.
  • the peeling roller 14 peels the film from the endless drum support 12, and guides the peeled film to the first stretching device 15.
  • stretching apparatus 15 is extended
  • the second stretching device 16 stretches in a direction (TD direction) perpendicular to the transport direction of the film while transporting the film stretched by the first stretching device 15.
  • the cutting device 17 cuts both ends in the direction (width direction) perpendicular to the transport direction of the film stretched by the second stretching device 16 and removes the cut ends.
  • stretching apparatus 18 is extended
  • the said winding apparatus 20 winds up the film extended
  • the film which comprises this film roll is the optical film manufactured by the manufacturing method of the optical film which concerns on this embodiment.
  • the endless drum support 12 and the casting die 13 correspond to those for performing a casting process.
  • the peeling step is a step of peeling from the endless drum support 12 using the cast film as a film, and is a step performed by the peeling roller 14.
  • the first stretching step is a step of stretching in the film transport direction after peeling from the endless drum support 12 until the first stretching step is performed in the second stretching step until stretching in the direction perpendicular to the film transport direction. It is a process performed by the peeling roller 14 and the first stretching device 15.
  • the cutting device 17 corresponds to a device for performing a cutting process.
  • stretching apparatus 18 is corresponded for implementing a 3rd extending
  • the manufacturing apparatus 11 of the said optical film is equipped with the thing for each performing a casting process, a peeling process, a 1st extending process, a 2nd extending process, a cutting process, and a 3rd extending process, It is not limited.
  • the casting die 13 is supplied with a dope 19 from a dope supply pipe connected to the upper end of the casting die 13. Then, the supplied dope is discharged from the casting die 13 to the endless drum support 12, and a web is formed on the endless drum support 12.
  • the endless drum support 12 is a rotating metal drum having a mirror surface.
  • a drum made of stainless steel or the like is preferably used from the viewpoint of peelability of the film.
  • the width of the casting film cast by the casting die 13 is 80 to 99% of the width of the endless drum support 12 from the viewpoint of effectively utilizing the width of the endless drum support 12. Is preferred.
  • a metal endless belt (endless belt support) having a mirror surface and traveling infinitely may be used.
  • Specific examples of the endless belt support include a belt supported so as to be drivable by a pair of drive rollers and a driven roller.
  • the endless drum support 12 dries the solvent in the dope while conveying the cast film (web) formed on the surface by the rotation of the endless drum support 12.
  • the endless drum support 12 is preferably cooled. Specifically, for example, it is preferably 10 ° C. or lower, more preferably 0 ° C. or lower, and further preferably ⁇ 10 ° C. or lower. By doing so, the strength of the obtained film tends to be improved. This is presumably because the cast film (web) formed on the surface of the endless drum support 12 becomes a gel film with high strength by cooling gelation.
  • the traveling speed (circumferential speed) of the endless drum support 12 is preferably about 50 to 300 m / min, for example.
  • the ratio (draft ratio) of the traveling speed of the endless drum support 12 to the flow rate of the dope discharged from the casting die 13 is preferably about 0.5 to 2.
  • the draft ratio is within this range, the cast film can be stably formed.
  • the draft ratio is too large, there is a tendency to cause a phenomenon called neck-in in which the cast film is reduced in the width direction, and if so, a wide optical film cannot be formed.
  • the temperature of the endless belt support varies depending on the solvent constituting the web, but the temperature of the endless belt support is 0 ° C. or higher. Generally, it is less than the boiling point of the solvent to be used. In consideration of the conveyance speed and productivity accompanying the evaporation time of the solvent, for example, the temperature is preferably 5 ° C. or higher and 5 ° C. or lower than the boiling point of the solvent constituting the web.
  • the atmospheric temperature at this time is not particularly limited, but is generally controlled to be higher than the dew point.
  • the peeling roller 14 is capable of peeling the film formed on the endless drum support 12 from the endless drum support 12 and guiding the peeled film to the first stretching device 15.
  • the peeling roller 14 is disposed, for example, in the vicinity of the surface of the endless drum support 12 on the side where the dope 19 is cast.
  • the distance between the endless drum support 12 and the peeling roller 14 is preferably 1 to 100 mm.
  • the peeling roller 14 as a fulcrum, the dried web (film) is peeled by pulling the dried web (film) with tension.
  • the film is stretched in the film transport direction (MD direction) by the peeling tension and the subsequent transport tension. For this reason, it is preferable that the peeling tension and the conveying tension when peeling the film from the endless drum support 12 are 50 to 400 N / m.
  • the residual solvent rate of the film when peeling the film from the endless drum support 12 is the peelability from the endless drum support 12, the residual solvent rate at the time of peeling, the transportability after peeling, and after transporting and drying. Considering the physical properties of the resulting resin film, it is preferably 30 to 200% by mass.
  • the residual solvent rate of a film is defined by following formula (2).
  • Residual solvent ratio (mass%) ⁇ (M 1 ⁇ M 2 ) / M 2 ⁇ ⁇ 100 (2)
  • M 1 is shows the mass at any point in the film
  • M 2 shows the mass after drying for 1 hour at 115 ° C. The film was measured M 1.
  • the first stretching device 15 is not particularly limited as long as it can be stretched in the transport direction (MD direction) of the film while transporting the film.
  • the first stretching device 15 includes, for example, a plurality of transport rollers. Then, the film is stretched in the MD direction by transporting the film between the rollers while the film is under tension. Note that the stretching ratio in the first stretching device 15, that is, the first stretching ratio may be within the above-described range.
  • the first stretching device 15 usually stretches the film and dries it.
  • air or infrared rays may be used alone and dried, or air and infrared rays may be used in combination.
  • the first stretching device 15 includes a box having an air inlet and an outlet, so that air is fed into the box from the air inlet. It may be.
  • the atmospheric temperature in the first stretching device 15 specifically, when the box is provided, the temperature in the box is preferably 5 to 39 ° C.
  • the temperature in the box is preferably 5 to 39 ° C.
  • the drying of the film is difficult to proceed and the solvent tends to remain in the film.
  • the said temperature is too high, there exists a tendency for film strength to fall, and there exists a possibility that a film may fracture
  • the surface temperature of the transport roller is preferably ⁇ 20 to 0 ° C. If the temperature is too low, condensation may occur on the surface of the film, or condensation generated on the transport roller may be transferred to the film, resulting in damage to the flatness of the film or the cause of foreign matter. , Film quality tends to decrease. Moreover, when the said temperature is too high, there exists a tendency which cannot fully exhibit the effect which improves the intensity
  • the second stretching device 16 is not particularly limited as long as it can stretch in the direction (TD direction) perpendicular to the transport direction of the film while transporting the film.
  • the both ends in the direction perpendicular to the film transport direction are gripped by clips or the like as gripping means, and the distance between the opposing clips is increased to extend in the TD direction.
  • the film is stretched so that the stretching ratio (TD stretching ratio) obtained by the following formula (3) is 20 to 50%.
  • the stretching ratio is preferably 22 to 48%, more preferably 25 to 45%.
  • the film may tear and break from the portion gripped by the gripping means (clip).
  • TD stretching ratio (%) ⁇ (length in the width direction after stretching ⁇ length in the width direction before stretching) / length in the width direction before stretching ⁇ ⁇ 100 (3)
  • the film when the film is stretched, the film is usually heated.
  • the heating of the film may be performed, for example, by blowing heated air on the film, or may be performed by a heating device such as an infrared heater.
  • the second stretching device 16 includes a box having an air inlet and an outlet, and feeds heated air from the air inlet into the box. You may do it.
  • the temperature at which the stretching is performed is preferably 150 to 200 ° C., and more preferably 155 to 190 ° C. If the stretching temperature is too low, excessive stress is applied to the film, so that the haze of the film increases and the transparency tends to decrease. For this reason, when the obtained resin film is used as a retardation film provided in a liquid crystal display device such as a liquid crystal panel, the contrast tends to decrease, which is not preferable. In some cases, the film may tear and break from the portion gripped by the gripping means (clip). On the other hand, if the stretching temperature is too high, a desired retardation value cannot be obtained or the film is melted, and the surface state and film thickness of the film tend to be non-uniform.
  • the cutting device 17 is not particularly limited as long as it can cut both ends in the direction (width direction) perpendicular to the film transport direction and remove the cut ends.
  • Specific examples of the cutting device 17 include those having a trim cutter.
  • the trim cutter cuts off the end in the direction (width direction) substantially perpendicular to the transport method of the film that has been transported, and cuts so that the remaining portion of the cut film becomes an optical film as a shipping product. At that time, as shown in FIG. 1, the end portion of the cut film is removed from the film conveyance path and removed.
  • the trim cutter is not particularly limited as long as the end of the conveyed film can be cut off.
  • the trim cutter it is preferable that the depth of cut with respect to the film can be arbitrarily adjusted in order to appropriately cut the end of the film.
  • the trim cutter includes a cutting blade composed of an upper round blade and a lower round blade. Rotating disc type or knife type.
  • the third stretching device 18 is not particularly limited as long as it can be stretched in the transport direction (MD direction) of the film while transporting the film from which the cut ends have been removed. Specifically, it is the same as that of the said 1st extending
  • the winding device 20 is not particularly limited as long as the film can be wound on the core to the required length.
  • the temperature at the time of winding is cooled to room temperature in order to prevent abrasion, loosening, and the like due to shrinkage after winding.
  • the winder to be used can be used without any particular limitation, and may be a commonly used one, such as a constant tension method, a constant torque method, a taper tension method, or a program tension control method with a constant internal stress. Can be wound up.
  • the resin solution used in the present embodiment is not particularly limited as long as it is obtained by dissolving an acrylic resin and a cellulose ester resin in a solvent at a mass ratio of 95: 5 to 30:70 as described above.
  • the said acrylic resin will not be specifically limited if it is resin which can exhibit transparency to the resin film obtained by shape
  • it is an acrylic resin that can be contained in the obtained film in a compatible state with the cellulose ester resin, and preferably has high compatibility.
  • the properties of each resin can be supplemented with each other to achieve physical properties and quality required as an optical film.
  • the inclusion of the acrylic resin and the cellulose ester resin in a compatible state means mixing the respective resins (polymers) to result in a compatible state. ing.
  • Whether or not the acrylic resin and the cellulose ester resin are in a compatible state can be specifically determined by, for example, measuring the glass transition temperature Tg. More specifically, for example, it can be determined from the following. Even when the glass transition temperatures of the two resins are different, one glass transition temperature is measured when the compatibility of the two resins is high. That is, the glass transition temperature specific to each resin disappears and is measured as one glass transition temperature. On the other hand, when the compatibility of both resins is low, the glass transition temperature of each resin is present, so two or more glass transition temperatures of the mixture are measured.
  • the glass transition temperature here was measured at a heating rate of 20 ° C./min using a differential scanning calorimeter (DSC-7 model manufactured by Perkin Elmer), and determined according to JIS K7121 (1987).
  • the midpoint glass transition temperature (Tmg) is used.
  • the acrylic resin is not particularly limited as long as it is an acrylic resin as described above. Specifically, for example, resins obtained by polymerizing monomers containing acrylic monomers such as acrylic acid esters and methacrylic acid esters such as methyl methacrylate are listed. More specifically, for example, a methacrylic resin such as polymethyl methacrylate can be used.
  • the monomer preferably includes 50 to 99% by mass of methyl methacrylate and 1 to 50% by mass of another monomer copolymerizable with methyl methacrylate. Therefore, the acrylic resin includes a resin obtained by polymerizing a monomer containing 50 to 99% by mass of methyl methacrylate and 1 to 50% by mass of another monomer copolymerizable with methyl methacrylate. preferable.
  • the other monomer copolymerizable with methyl methacrylate is not particularly limited.
  • alkyl methacrylate having 2 to 18 carbon atoms in the alkyl group alkyl acrylate having 1 to 18 carbon atoms in the alkyl group, and acrylic ⁇ , ⁇ -unsaturated acids such as acid and methacrylic acid, divalent carboxylic acids containing unsaturated groups such as maleic acid, fumaric acid and itaconic acid, aromatic vinyl compounds such as styrene and ⁇ -methylstyrene, acrylonitrile, methacrylo
  • ⁇ , ⁇ -unsaturated nitriles such as nitrile, maleic anhydride, maleimide, N-substituted maleimide, and glutaric anhydride.
  • methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, s-butyl acrylate, 2-ethylhexyl acrylate, and the like are preferable from the viewpoint of thermal decomposition resistance and fluidity of the copolymer.
  • Particularly preferred are acrylates and n-butyl acrylate.
  • acrylic resin a commercially available product can also be used.
  • Delpet 60N manufactured by Asahi Kasei Chemicals Corporation Delpet 80N manufactured by Asahi Kasei Chemicals Corporation, Dialar BR52 manufactured by Mitsubishi Rayon Co., Ltd., Dialnal BR80 manufactured by Mitsubishi Rayon Co., Ltd., Mitsubishi Rayon Co., Ltd.
  • Examples include company-made Dianar BR83, Mitsubishi Rayon Co., Ltd., Dianar BR85, Mitsubishi Rayon Co., Ltd., Dianar BR88, and Electrochemical Industry Co., Ltd. KT75.
  • acrylic resin may be used alone or in combination of two or more of the acrylic resins described above.
  • the acrylic resin has a weight average molecular weight (Mw) of 110,000 to 1 in particular from the viewpoint of improving brittleness as a protective film for a liquid crystal polarizing plate and improving transparency when it is compatible with a cellulose ester resin. It is preferably 1 million, more preferably 150,000 to 400,000.
  • the weight average molecular weight can be measured by gel permeation chromatography. Examples of the measurement conditions include the following conditions.
  • the method for producing the acrylic resin is not particularly limited as long as the above-mentioned acrylic resin is obtained. Specifically, for example, it can be produced by polymerizing a monomer containing an acrylic monomer such as acrylic acid ester and methacrylic acid ester as described above by a known polymerization method.
  • the polymerization method is not particularly limited, and examples thereof include suspension polymerization, emulsion polymerization, bulk polymerization, and solution polymerization.
  • the polymerization initiator used in the polymerization method is not particularly limited as long as the polymerization reaction can be initiated. For example, a peroxide polymerization initiator, an azo polymerization initiator, a redox polymerization initiator, and the like. Is mentioned.
  • the polymerization temperature in the polymerization method is not particularly limited as long as it is a temperature at which the polymerization reaction can proceed.
  • the temperature is preferably 30 to 100 ° C. in the case of suspension polymerization or emulsion polymerization, and preferably 80 to 160 ° C. in the case of bulk polymerization or solution polymerization.
  • the cellulose ester resin may be a resin that can exhibit transparency in a resin film obtained by molding into a film using a dope that is obtained together with the acrylic resin.
  • the total substitution degree (T) of the acyl group is 2 to 3, and the carbon number is 3 to 7.
  • a cellulose ester resin having an acyl group substitution degree of 1.2 to 3 is preferred. Further, the substitution degree of the acyl group having 3 to 7 carbon atoms is more preferably 2 to 3.
  • a cellulose ester resin substituted with an acyl group having 3 to 7 carbon atoms and having a substitution degree of 2 to 3 is particularly preferable.
  • the acyl group include a propionyl group and a butyryl group, and a propionyl group is preferably used.
  • the compatibility with the acrylic resin is high. There is a tendency that the haze of the obtained optical film is increased due to insufficiency.
  • the compatibility with the acrylic resin may be insufficient or obtained. The brittleness of the optical film tends to decrease.
  • the substitution degree of the acyl group having 2 carbon atoms for example, the acetyl group is high and the acyl group having 3 to 7 carbon atoms is substituted.
  • the degree is less than 1.2, the compatibility tends to decrease and the haze tends to increase.
  • the substitution degree of the acyl group having 8 or more carbon atoms is high and the substitution degree of the acyl group having 3 to 7 carbon atoms is less than 1.2. The brittleness tends to deteriorate and the desired characteristics cannot be obtained.
  • the cellulose ester-based resin has a total substitution degree (T) of 2 to 3, and a substitution degree of an acyl group having 3 to 7 carbon atoms is 1.2 to 3.
  • T total substitution degree
  • the total degree of substitution of acyl groups other than those having 3 to 7 carbon atoms, that is, acetyl groups or acyl groups having 8 or more carbon atoms is more preferably 1.3 or less.
  • the total substitution degree (T) of the acyl group of the cellulose ester resin is more preferably in the range of 2.5 to 3.
  • the acyl group is not particularly limited, and may be an aliphatic acyl group or an aromatic acyl group. In the case of an aliphatic acyl group, it may be linear or branched and may further have a substituent.
  • the carbon number of the acyl group includes the carbon number of the substituent of the acyl group.
  • the number of substituents X substituted on the aromatic ring is preferably 0 to 5.
  • the substitution degree of the acyl group having 3 to 7 carbon atoms including the carbon number of the substituent is preferably 1.2 to 3.
  • the benzoyl group has 7 carbon atoms, when it has a substituent containing carbon, the benzoyl group has 8 or more carbon atoms and is not included in the acyl group having 3 to 7 carbon atoms. It will be.
  • substituents substituted on the aromatic ring when the number of substituents substituted on the aromatic ring is 2 or more, they may be the same as or different from each other. Further, they may be linked to each other to form a condensed polycyclic compound such as naphthalene, indene, indane, phenanthrene, quinoline, isoquinoline, chromene, chroman, phthalazine, acridine, indole, indoline and the like.
  • a condensed polycyclic compound such as naphthalene, indene, indane, phenanthrene, quinoline, isoquinoline, chromene, chroman, phthalazine, acridine, indole, indoline and the like.
  • the cellulose ester resin is not particularly limited as long as it is a cellulose ester resin as described above. Specifically, for example, cellulose acetate propionate resin, cellulose acetate butyrate resin, cellulose acetate benzoate resin, cellulose propionate resin, and cellulose butyrate resin are preferably used. That is, a cellulose ester resin having an acyl group having 3 or 4 carbon atoms as a substituent is preferable. Among these, cellulose acetate propionate resin and cellulose propionate resin are particularly preferable. In addition, the portion that is not substituted with an acyl group usually exists as a hydroxyl group.
  • the cellulose ester resin can be synthesized by a known method.
  • the degree of substitution of the acetyl group and the degree of substitution of other acyl groups are values measured by a method according to ASTM-D817-96.
  • the weight average molecular weight (Mw) of the cellulose ester-based resin is preferably 75,000 or more, more preferably 75,000 to 300,000, and more preferably 100,000 to 24,000, particularly from the viewpoint of improving compatibility with acrylic resin and brittleness. More preferably, it is more preferably from 160000 to 240000. If the weight average molecular weight (Mw) of the cellulose ester resin is too small, the heat resistance and brittleness improvement effects tend to be insufficient.
  • the cellulose ester resin may be used in combination of two or more cellulose ester resins. In addition, the weight average molecular weight (Mw) of the said cellulose ester-type resin can be measured similarly to the said acrylic resin.
  • the content ratio of the acrylic resin to the cellulose ester resin is 95: 5 to 30:70 by mass ratio, preferably 95: 5 to 50:50, and 90:10 to 60:40. More preferably. If the content of the acrylic resin is too large relative to the cellulose ester resin, the effect of the cellulose ester resin tends to be insufficient. In addition, if the content of the acrylic resin is too small relative to the cellulose ester resin, the effect of the acrylic resin cannot be sufficiently exerted, for example, the moisture resistance of the obtained optical film is insufficient. Tend to be.
  • the solvent used in the present embodiment is not particularly limited as long as it can dissolve the acrylic resin and the cellulose ester resin.
  • a chlorinated organic solvent such as methylene chloride, and methyl acetate, ethyl acetate, amyl acetate, acetone, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, cyclohexanone, ethyl formate, 2,2 , 2-trifluoroethanol, 2,2,3,3-hexafluoro-1-propanol, 1,3-difluoro-2-propanol, 1,1,1,3,3,3-hexafluoro-2-methyl
  • Non-chlorine organic solvents such as -2-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 2,2,3,3,3-pentafluoro-1-propanol, nitroethane, etc. Is mentioned.
  • the solvent preferably contains a linear or branched aliphatic alcohol having 1 to 4 carbon atoms.
  • the content thereof is preferably 1 to 40% by mass with respect to the whole solvent.
  • a solvent containing methylene chloride and a linear or branched aliphatic alcohol having 1 to 4 carbon atoms is mixed with the acrylic resin, the cellulose ester resin, the acrylic particles, and a surfactant.
  • a dope composition in which at least 15 to 45 mass% in total of three kinds of premixed mixtures is dissolved is preferable.
  • linear or branched aliphatic alcohol having 1 to 4 carbon atoms examples include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, tert-butanol and the like. It is done.
  • additives may be appropriately blended with the dope.
  • the additive include acrylic particles, plasticizers, antioxidants, and ultraviolet absorbers.
  • the acrylic particles are not particularly limited as long as they are insoluble in the solvent, unlike the acrylic resin.
  • the optical film containing the acrylic resin and the cellulose ester resin in a compatible state may be particles containing an acrylic resin that exists in a particle state, that is, in an incompatible state. preferable. More specifically, for example, a predetermined amount of the obtained optical film is collected, stirred in a solvent, and a solution in which a component dissolved in the solvent is sufficiently dissolved is a pore size smaller than the volume average particle size of the acrylic particles. It is preferable that the weight of the insoluble matter filtered and collected using a PTFE membrane filter having a weight of 90% by mass or more of the acrylic particles added to the optical film.
  • the acrylic particle is not particularly limited as long as it is an acrylic particle as described above. Specifically, for example, acrylic particles in which a layer structure of two or more layers is formed are preferable, and a multilayer structure acrylic granular composite as described below is particularly preferable.
  • the multilayer structure acrylic granular composite is composed of an innermost hard layer polymer, a cross-linked soft layer polymer exhibiting rubber elasticity, and an outermost hard layer polymer layered in a layered manner from the center to the outer periphery. It is a particulate acrylic polymer in which a structure is formed. That is, the multilayer structure acrylic granular composite is a multilayer structure acrylic granular composite comprising an innermost hard layer, a crosslinked soft layer, and an outermost hard layer from the central portion toward the outer peripheral portion. A multilayer acrylic granular composite having such a three-layer core-shell structure is preferably used.
  • Preferred embodiments of the multilayer structure acrylic granular composite include the following. That is, the thing provided with what each layer formed as follows is mentioned.
  • Examples of the innermost hard layer polymer include 80 to 98.9% by mass of methyl methacrylate, 1 to 20% by mass of alkyl acrylate having 1 to 8 carbon atoms in the alkyl group, and 0.01 to And the like obtained by polymerizing a mixture of monomers consisting of 0.3% by mass.
  • cross-linked soft layer polymer examples include 75 to 98.5% by mass of an alkyl acrylate having 4 to 8 carbon atoms in the presence of the innermost hard layer polymer, and a polyfunctional cross-linking agent.
  • examples thereof include those obtained by polymerizing a monomer mixture comprising 0.01 to 5% by mass and a polyfunctional grafting agent 0.5 to 5% by mass.
  • the outermost hard layer polymer for example, in the presence of the polymer composed of the innermost hard layer and the cross-linked soft layer, 80 to 99% by mass of methyl methacrylate and 1 to 1 carbon atoms of the alkyl group. And the like obtained by polymerizing a mixture of monomers consisting of 1 to 20% by mass of alkyl acrylate 8.
  • each layer is 5 to 40% by mass of the innermost hard layer polymer, 30 to 60% by mass of the soft layer polymer, and 20 to 50% by mass of the outermost hard layer polymer.
  • a structural acrylic granular composite is preferred. Further, a multilayer structure acrylic granular composite having an insoluble part when fractionated with acetone and having a methyl ethyl ketone swelling degree of 1.5 to 4 in the insoluble part is more preferable.
  • each layer of the multilayer structure acrylic granular composite set the tensile modulus of the multilayer structure acrylic granular composite and the methyl ethyl ketone swelling degree of the acetone insoluble part within a specific range. By this, it becomes possible to realize a further sufficient balance between impact resistance and stress whitening resistance.
  • the range of the tensile modulus of elasticity and the degree of swelling of methyl ethyl ketone in the acetone-insoluble part of the multilayer structure acrylic granular composite is not particularly limited in the present embodiment. However, for example, Japanese Patent Publication No. 60-17406, And a range as disclosed in Japanese Patent Publication No. 3-39095.
  • Examples of the innermost hard layer polymer include 80 to 98.9% by mass of methyl methacrylate, 1 to 20% by mass of alkyl acrylate having 1 to 8 carbon atoms in the alkyl group, and 0.01 to What is obtained by superposing
  • examples of the alkyl acrylate having an alkyl group having 1 to 8 carbon atoms include methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, s-butyl acrylate, 2-ethylhexyl acrylate, and the like. Methyl acrylate and n-butyl acrylate are preferably used.
  • the thermal decomposability of the obtained innermost hard layer polymer tends to increase.
  • the content ratio of the alkyl acrylate is too high, the glass transition temperature of the innermost hard layer polymer is lowered, and the impact resistance imparting effect of the three-layer structure acrylic granular composite tends to be lowered.
  • polyfunctional grafting agent examples include polyfunctional monomers having different polymerizable functional groups such as acrylic acid, methacrylic acid, maleic acid, and fumaric acid allyl ester. Preferably used.
  • the polyfunctional grafting agent is used to chemically bond the innermost hard layer polymer and the soft layer polymer.
  • the blending ratio of the polyfunctional grafting agent when used during the innermost hard layer polymerization is preferably 0.01 to 0.3% by mass, for example.
  • crosslinked soft layer polymer examples include 75 to 98.5% by mass of an alkyl acrylate having an alkyl group having 1 to 8 carbon atoms in the presence of the innermost hard layer polymer, and a polyfunctional crosslinking agent of 0. What is obtained by polymerizing a mixture of monomers consisting of 01 to 5% by mass and a polyfunctional grafting agent 0.5 to 5% by mass is preferred.
  • n-butyl acrylate or 2-ethylhexyl acrylate is preferably used as the alkyl acrylate having 4 to 8 carbon atoms in the alkyl group.
  • Examples of other monofunctional monomers that can be copolymerized include styrene and substituted styrene derivatives.
  • the glass transition temperature of the crosslinked soft layer polymer decreases, that is, the ratio can be softened as the former increases.
  • the refractive index of the soft layer polymer at room temperature closer to the innermost hard layer polymer, the outermost hard layer polymer, and the acrylic resin.
  • the ratio between the two is selected in consideration of these factors.
  • examples of the polyfunctional grafting agent include the same polyfunctional grafting agents used for producing the innermost layer hard polymer.
  • the polyfunctional grafting agent used here is used to chemically bond the soft layer polymer and the outermost hard layer polymer.
  • the blending ratio of the polyfunctional grafting agent used during the innermost hard layer polymerization is preferably 0.5 to 5% by mass from the viewpoint of imparting impact resistance.
  • polyfunctional crosslinking agent generally known crosslinking agents such as divinyl compounds, diallyl compounds, diacrylic compounds, and dimethacrylic compounds can be used, but polyethylene glycol diacrylate (molecular weight 200 to 600) is preferably used.
  • the polyfunctional cross-linking agent used here is used for generating a cross-linked structure during the polymerization of the cross-linked soft layer polymer and exhibiting the effect of imparting impact resistance.
  • the above-mentioned polyfunctional grafting agent is used in the polymerization of the crosslinked soft layer polymer, a crosslinked structure of the crosslinked soft layer polymer is generated to some extent, so that the polyfunctional crosslinking agent is not an essential component.
  • the blending ratio of the polyfunctional crosslinking agent used in the polymerization of the crosslinked soft layer polymer is 0.01 to 5% by mass from the viewpoint of impact resistance imparting effect. Is preferred.
  • the outermost hard layer polymer is an alkyl acrylate 1 to 80 having a methyl methacrylate of 80 to 99% by mass and an alkyl group having 1 to 8 carbon atoms. What is obtained by polymerizing a mixture of monomers consisting of 20% by mass is preferred.
  • acrylic alkylate those described above are used, and methyl acrylate and ethyl acrylate are preferably used.
  • the proportion of the alkyl acrylate unit in the outermost hard layer polymer is preferably 1 to 20% by mass.
  • an alkyl mercaptan or the like can be used as a chain transfer agent to adjust the molecular weight for the purpose of improving compatibility with the acrylic resin.
  • the outermost hard layer with a gradient such that the molecular weight gradually decreases from the inside toward the outside in order to improve the balance between elongation and impact resistance.
  • the outermost hard layer is divided into two or more monomer mixtures for forming the outermost hard layer, and the amount of chain transfer agent to be added each time is increased sequentially. It is possible to decrease the molecular weight of the polymer forming the layer from the inside to the outside of the multilayer structure acrylic granular composite.
  • the molecular weight formed at this time can also be examined by polymerizing a mixture of monomers used each time under the same conditions, and measuring the molecular weight of the resulting polymer.
  • the mass ratio of the core and the shell is not particularly limited. Specifically, for example, when the whole multilayer structure acrylic granular composite is 100 parts by mass, the core layer is preferably 50 parts by mass or more and 90 parts by mass or less, and 60 parts by mass or more and 80 parts by mass or less. It is more preferable that The core layer here is the innermost hard layer.
  • Such a commercial product of an acrylic granular composite having a multilayer structure include, for example, Metablene manufactured by Mitsubishi Rayon Co., Ltd., Kane Ace manufactured by Kaneka Co., Ltd., Paraloid manufactured by Kureha Co., Ltd. -Examples include Acryloid manufactured by Hearth, Staphyloid manufactured by Gantz Kasei Co., Ltd., Parapet SA manufactured by Kuraray Co. These may be used alone or in combination of two or more.
  • graft copolymer particles are also preferably used.
  • the graft copolymer particles are, for example, an unsaturated carboxylic acid ester monomer, an unsaturated carboxylic acid monomer, and an aromatic vinyl monomer in the presence of a rubbery polymer.
  • the rubbery polymer include particles containing diene rubber, acrylic rubber, ethylene rubber, and the like. More specifically, for example, polybutadiene, styrene-butadiene copolymer, block copolymer of styrene-butadiene, acrylonitrile-butadiene copolymer, butyl acrylate-butadiene copolymer, polyisoprene, butadiene-methyl methacrylate copolymer.
  • Polymer butyl acrylate-methyl methacrylate copolymer, butadiene-ethyl acrylate copolymer, ethylene-propylene copolymer, ethylene-propylene-diene copolymer, ethylene-isoprene copolymer, and ethylene-acrylic Examples thereof include particles containing an acid methyl copolymer. These rubbery polymers may be used alone or in combination of two or more.
  • acrylic particles commercially available particles can also be used. Specific examples include Metabrene W-341 manufactured by Mitsubishi Rayon Co., Ltd., Chemisnow MR-2G manufactured by Soken Chemical Co., Ltd., and Chemisnow MS-300X manufactured by Soken Chemical Co., Ltd.
  • the content of the acrylic particles is not particularly limited. Specifically, for example, the content is preferably 0.5 to 30% by mass and more preferably 1 to 15% by mass with respect to the total mass of the resin constituting the optical film.
  • the particle diameter of the acrylic particles is not particularly limited. Specifically, for example, the thickness is preferably 10 nm or more and 1000 nm or less, more preferably 20 nm or more and 500 nm or less, and further preferably 50 nm or more and 400 nm or less.
  • the refractive index of the alkali particles is close to the refractive index of the acrylic resin or the mixture of the acrylic resin and the cellulose ester resin in order to obtain a highly transparent film.
  • the difference in refractive index between the acrylic particles and the acrylic resin is preferably 0.05 or less, more preferably 0.02 or less, and 0.01 or less. More preferably.
  • the method of adjusting the composition ratio of each monomer unit of the acrylic resin, and the composition ratio of the rubbery polymer or monomer used in the acrylic particles The method of preparation etc. are mentioned. By doing so, the said refractive index difference can be made small and the protective film for liquid crystal polarizing plates excellent in transparency can be obtained.
  • the difference in refractive index referred to here means that the protective film for a liquid crystal polarizing plate according to the present invention is sufficiently dissolved in a solvent in which an acrylic resin is soluble to obtain a cloudy solution, which is subjected to an operation such as centrifugation.
  • a solvent in which an acrylic resin is soluble to obtain a cloudy solution, which is subjected to an operation such as centrifugation.
  • the difference in the measured refractive index 23 ° C., measurement wavelength: 550 nm
  • the plasticizer is not particularly limited, and examples thereof include those added to impart appropriate flexibility to the obtained optical film.
  • ester plasticizers for example, ester plasticizers, phosphate ester plasticizers, phthalate ester plasticizers, trimellitic acid ester plasticizers, pyromellitic acid plasticizers, glycolic acid ester plasticizers, citric acid Examples include ester plasticizers and the glycol plasticizers.
  • the ester plasticizer is formed, for example, from a polybasic acid such as an aliphatic dibasic acid, an alicyclic dibasic acid, or an aromatic dibasic acid and a polyhydric alcohol such as glycol. And the like.
  • the aliphatic dibasic acid can be used without any particular limitation, and specific examples include adipic acid, sebacic acid, phthalic acid, terephthalic acid, 1,4-cyclohexyl dicarboxylic acid, and the like.
  • phosphate ester plasticizer examples include triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, diphenyl biphenyl phosphate, trioctyl phosphate, tributyl phosphate, and the like.
  • phthalate ester plasticizer examples include diethyl phthalate, dimethoxyethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, and butyl benzyl phthalate.
  • trimellitic acid plasticizer examples include tributyl trimellitate, triphenyl trimellitate, triethyl trimellitate, and the like.
  • pyromellitic acid ester plasticizer examples include tetrabutyl pyromellitate, tetraphenyl pyromellitate, tetraethyl pyromellitate, and the like.
  • glycolic acid ester plasticizer examples include triacetin, tributyrin, ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate, and butyl phthalyl butyl glycolate.
  • citrate plasticizer examples include triethyl citrate, tri-n-butyl citrate, acetyl triethyl citrate, acetyl tri-n-butyl citrate, acetyl tri-n- (2 -Ethylhexyl) citrate and the like.
  • glycol plasticizer examples include ethylene glycol, diethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, 1,4-butylene glycol, 1,3-butylene glycol, 1,2-butylene glycol and the like. Is mentioned.
  • the above plasticizers may be used alone or in combination of two or more.
  • the antioxidant is not particularly limited.
  • a hindered phenol compound is preferably used.
  • hydrazine-based metal deactivators such as N, N′-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine and tris (2,4-di- A phosphorus processing stabilizer such as t-butylphenyl) phosphite may be used in combination.
  • the optical film manufactured using the dope obtained by the manufacturing method according to the present embodiment can be used for a protective film for a polarizing plate, and in this case, for preventing deterioration of the polarizing plate or liquid crystal.
  • An ultraviolet absorber is preferably used.
  • the ultraviolet absorber those having excellent absorption ability of ultraviolet rays having a wavelength of 370 nm or less and having little absorption of visible light having a wavelength of 400 nm or more are preferably used from the viewpoint of good liquid crystal display properties.
  • the transmittance at 380 nm is preferably less than 10%, more preferably less than 5%.
  • UV absorber examples include oxybenzophenone compounds, benzotriazole compounds (benzotriazole UV absorbers), salicylic acid ester compounds, benzophenone compounds (benzophenone UV absorbers), and cyanoacrylates. Compounds, nickel complex compounds, triazine compounds, and the like.
  • benzotriazole UV absorbers and benzophenone UV absorbers are preferable.
  • Specific examples of the benzotriazole-based UV absorber and the benzophenone-based UV absorber are given below, but the present invention is not limited thereto.
  • benzotriazole ultraviolet absorber examples include 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-). tert-butylphenyl) benzotriazole, 2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-tert- Butylphenyl) -5-chlorobenzotriazole, 2- (2′-hydroxy-3 ′-(3 ′′, 4 ′′, 5 ′′, 6 ′′ -tetrahydrophthalimidomethyl) -5′-methylphenyl) benzotriazole, 2, 2-methylenebis (4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol), 2- 2'-hydroxy-3'-tert-butyl-5'-methylphenyl) -5-chlorobenzotriazo
  • benzophenone ultraviolet absorber examples include 2,4-dihydroxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, bis ( 2-methoxy-4-hydroxy-5-benzoylphenylmethane) and the like.
  • a resin solution can be obtained by mixing the above-described compositions.
  • the obtained dope is preferably filtered using a suitable filter medium such as filter paper.
  • the optical film obtained as described above is an optical film containing an acrylic resin in a cellulose ester resin in order to improve moisture resistance, heat resistance, etc., and has transparency, workability, and flatness. It has excellent properties.
  • the haze of the obtained optical film is preferably 0.3 or less, and more preferably 0.1 or less, although it varies depending on the composition and the like.
  • the haze of the optical film can be measured according to JIS K 7136. Specifically, it can be measured using, for example, a haze meter (NDH2000 type manufactured by Nippon Denshoku Industries Co., Ltd.).
  • the width of the optical film is preferably 1000 to 4000 mm from the viewpoint of use in a large liquid crystal display device, use efficiency of the optical film during polarizing plate processing, and production efficiency.
  • the film thickness of the optical film is preferably 30 to 90 ⁇ m from the viewpoint of thinning the liquid crystal display device and stabilizing the production of the optical film.
  • the film thickness is an average film thickness. The film thickness is measured at 20 to 200 locations in the width direction of the optical film with a contact-type film thickness meter manufactured by Mitutoyo Corporation, and the average value of the measured values. Is shown as the film thickness.
  • the said optical film can be used as a transparent protective film for polarizing plates for protecting the polarizing element of a polarizing plate.
  • the polarizing plate includes, for example, a polarizing element and a transparent protective film disposed on the surface of the polarizing element.
  • the resin film can be used as the transparent protective film.
  • the polarizing element is an optical element that emits incident light converted to polarized light.
  • polarizing plate for example, a completely saponified polyvinyl alcohol aqueous solution is used on at least one surface of a polarizing element produced by immersing and stretching a polyvinyl alcohol film in an iodine solution.
  • a laminate is preferred.
  • the said optical film may be laminated
  • the transparent protective film for the polarizing plate for example, as a commercially available cellulose ester film, KC8UX2M, KC4UX, KC5UX, KC4UY, KC8UY, KC12UR, KC8UY-HA, KC8UX-RHA (above, manufactured by Konica Minolta Opto) Is preferably used.
  • resin films such as cyclic olefin resin other than a cellulose-ester film, an acrylic resin, polyester, a polycarbonate. In this case, since the saponification suitability is low, it is preferable to perform an adhesive process on the polarizing plate through an appropriate adhesive layer.
  • the polarizing plate uses the optical film as a transparent protective film laminated on at least one surface side of the polarizing element.
  • the said optical film functions as a phase difference film, it is preferable to arrange
  • polarizing element examples include, for example, a polyvinyl alcohol polarizing film.
  • Polyvinyl alcohol polarizing films include those obtained by dyeing iodine on polyvinyl alcohol films and those obtained by dyeing dichroic dyes.
  • a modified polyvinyl alcohol film modified with ethylene is preferably used as the polyvinyl alcohol film.
  • the polarizing element is obtained as follows, for example. First, a film is formed using a polyvinyl alcohol aqueous solution. The obtained polyvinyl alcohol film is uniaxially stretched and then dyed or dyed and then uniaxially stretched. And preferably, a durability treatment is performed with a boron compound.
  • the film thickness of the polarizing element is preferably 5 to 40 ⁇ m, more preferably 5 to 30 ⁇ m, and even more preferably 5 to 20 ⁇ m.
  • a cellulose ester resin film When a cellulose ester resin film is laminated on the surface of the polarizing element, it is preferably bonded with a water-based adhesive mainly composed of completely saponified polyvinyl alcohol. Moreover, in the case of resin films other than a cellulose ester-based resin film, it is preferable to perform adhesion processing on the polarizing plate through an appropriate adhesive layer.
  • the polarizing plate as described above uses the optical film according to this embodiment as a transparent protective film, the optical film is excellent in transparency, heat resistance, moisture resistance, and workability.
  • a polarizing plate that can be suitably used for a large-screen liquid crystal display device is obtained.
  • even a polarizing plate for a liquid crystal display device having a large screen can suppress deformation due to moisture absorption.
  • an optical film with favorable workability is used as the transparent protective film, the occurrence of damage is suppressed even when a large film is used.
  • the polarizing plate provided with the said optical film can be used as a polarizing plate provided in a liquid crystal display device.
  • a liquid crystal display device is provided with a liquid crystal cell and two polarizing plates arrange
  • the polarizing plate can be used as at least one of the two polarizing plates.
  • the liquid crystal cell is a cell in which a liquid crystal substance is filled between a pair of electrodes, and by applying a voltage to the electrodes, the alignment state of the liquid crystal is changed and the amount of transmitted light is controlled.
  • Such a liquid crystal display device uses the optical film according to this embodiment as a transparent protective film for a polarizing plate, so that the optical film has excellent transparency, heat resistance, moisture resistance, and workability. Since the film is provided, it is possible to provide a liquid crystal display device in which occurrence of defects in the optical film disposed in the image display area is suppressed even when the screen is enlarged. In addition, since the processability of the optical film is good, even in the case of a large film that is applied to a large-screen liquid crystal display device, since the occurrence of damage to the optical film is suppressed during production, A liquid crystal display device having a large screen can be provided.
  • the obtained copolymer was blended with NaOCH 3 as an additive so that 0.2 wt%.
  • the mixture was kneaded under the conditions of a screw rotation speed of 100 rpm and a raw material (formulation) supply rate of 5 kg / hour. By doing so, a pellet-shaped resin was obtained. And the obtained pellet was vacuum-dried at 80 degreeC for 8 hours. By doing so, an acrylic resin was obtained.
  • the obtained acrylic resin was a product obtained by intramolecular cyclization reaction of the blend.
  • the weight average molecular weight of the obtained acrylic resin was 300,000, and the glass transition temperature (Tg) was 130 degreeC.
  • Tg glass transition temperature
  • the weight average molecular weight is measured by gel permeation chromatography (GPC), and Tg is measured by a differential scanning calorimeter (DSC).
  • the cellulose acetate propionate resin (acyl group total substitution degree: 2.75, acetyl group substitution degree: 0.19, propionyl group substitution degree: 70 parts by mass of the acrylic resin produced by the production method as a cellulose ester resin. 2.56, Mw: 200000) was added in 30 parts by mass.
  • the content of the acrylic resin (acrylic resin / acrylic resin + cellulose ester resin: A mass%) with respect to the total amount of the acrylic resin and the cellulose ester resin is 70 mass%.
  • the mixture was stirred for 3 hours. By doing so, a resin solution was obtained. Then, stirring was complete
  • the resin solution thus obtained was used as a dope to produce an optical film as follows.
  • the temperature of the obtained dope was adjusted to 35 ° C., and the temperature of the endless belt support was adjusted to 25 ° C. Then, using an optical film manufacturing apparatus as shown in FIG. 1, the dope is applied to an endless drum support made of stainless steel and a metal drum polished to a super mirror surface at a conveyance speed of 60 m / min from the casting die. Extended. By doing so, a web was formed on the endless drum support and conveyed while drying. Then, the web was peeled off as a film from the endless drum support. Thereafter, the peeled film was stretched in the MD direction by the first stretching device, and stretched in the TD direction by the second stretching device.
  • both ends of a film are cut and removed with a cutting device. Thereafter, both ends were removed, and the film was stretched in the MD direction with a third stretching device. And the optical film wound up in roll shape was obtained by winding up a film into 8000 m length. The width of the obtained film was 2300 mm and the thickness was 40 ⁇ m.
  • the stretching conditions such as the film transport tension were adjusted so that the stretching ratios in the first stretching apparatus and the third stretching apparatus were the stretching ratios shown in Table 1.
  • the stretching conditions such as the conveyance tension of the film were adjusted so that the ratio of the first stretching ratio to the total stretching ratio (first stretching ratio / total stretching ratio in the MD direction) was a value as shown in Table 1.
  • stretching apparatus was set to 35 degreeC, and the temperature of the conveyance roller in a 1st extending
  • Examples 2 to 4 and Comparative Examples 1 to 4 The stretching ratio in the first stretching apparatus and the third stretching apparatus is such that the total stretching ratio in the MD direction and the first stretching ratio / total stretching ratio in the MD direction are the stretching ratios as shown in Table 1.
  • An optical film was produced in the same manner as in Example 1 except that the stretching conditions such as the film transport tension were changed.
  • Example 5 An optical film was produced in the same manner as in Example 2 except that the temperature of the conveying roller in the first stretching apparatus was set to ⁇ 15 ° C.
  • Example 6 An optical film was produced in the same manner as in Example 2 except that the atmospheric temperature in the first stretching apparatus was set to 60 ° C.
  • Example 7 Using the dope 2 described later, the stretching ratio in the first stretching apparatus and the third stretching apparatus is such that the total stretching ratio in the MD direction and the first stretching ratio / total stretching ratio in the MD direction are the values shown in Table 1.
  • An optical film was produced in the same manner as in Example 1 except that the stretching conditions such as the conveyance tension of the film were changed so as to obtain a stretching ratio.
  • Example 8 Using the dope 3 described later, the stretching ratio in the first stretching apparatus and the third stretching apparatus is such that the total stretching ratio in the MD direction and the first stretching ratio / total stretching ratio in the MD direction are the values shown in Table 1.
  • An optical film was produced in the same manner as in Example 1 except that the stretching conditions such as the conveyance tension of the film were changed so as to obtain a stretching ratio.
  • the stretching ratio in the first stretching apparatus and the third stretching apparatus is such that the total stretching ratio in the MD direction and the first stretching ratio / total stretching ratio in the MD direction are the values shown in Table 1.
  • An optical film was produced in the same manner as in Example 1 except that the stretching conditions such as the conveyance tension of the film were changed so as to obtain a stretching ratio.
  • the stretching ratio in the first stretching apparatus and the third stretching apparatus is such that the total stretching ratio in the MD direction and the first stretching ratio / total stretching ratio in the MD direction are the values shown in Table 1.
  • An optical film was produced in the same manner as in Example 1 except that the stretching conditions such as the conveyance tension of the film were changed so as to obtain a stretching ratio.
  • the haze of the obtained optical film was measured according to JIS K7136. Specifically, it measured using the haze meter (NDH2000 type
  • the obtained optical film was torn using a light load tear tester manufactured by Toyo Seiki Seisakusho Co., Ltd., and the tear surface and the like were visually confirmed. At that time, the tearing surface is very smooth and straight, and if the generation of chips on the tearing surface is not confirmed, it is evaluated as ⁇ ⁇ '', although the tearing surface is very smooth and straight, If generation of chips is confirmed on the tear surface, it is evaluated as ⁇ ⁇ '', and it is confirmed that flash is generated on the tear surface, it is not torn straight, or a large amount of chips is generated on the tear surface. It was evaluated as “ ⁇ ”.
  • the dope contains acrylic resin and cellulose ester resin in a mass ratio of 95: 5 to 30:70 (acrylic resin content A is 30 to 95% by mass).
  • the total stretching ratio in the MD direction is A / 3 + 10 to A / 5 + 40 and the ratio of the first stretching ratio to the total stretching ratio in the MD direction is 70 to 95% (Example 1) 8) to 8)
  • Example 1 the ratio of the first stretching ratio to the total stretching ratio in the MD direction is 70 to 95%
  • Comparative Examples 1 to 6 in order to improve moisture resistance, heat resistance, etc., compared with the case where any of them is not satisfied
  • An optical film excellent in processability and flatness such as transparency and cutting property can be produced.
  • One aspect of the present invention is to cast a resin solution containing an acrylic resin and a cellulose ester resin at a mass ratio of 95: 5 to 30:70 onto a traveling support to form a cast film.
  • a casting process a peeling process for peeling the cast film from the support as a film, a first stretching process for stretching the peeled film in the transport direction while transporting the peeled film, and the first stretching process.
  • a second stretching step for stretching in a direction perpendicular to the transport direction of the film while transporting the film stretched by the step, and a direction perpendicular to the transport direction of the film while transporting the film stretched by the second stretching step.
  • the total of the stretch ratio of the film in the first stretching step and the stretch ratio of the film in the third stretching step is that of the acrylic resin with respect to the total amount of the acrylic resin and the cellulose ester resin.
  • the content rate is A mass%, it is in the range of A / 3 + 10 to A / 5 + 40 in terms of percentage, and the stretch ratio of the film in the first stretching step is the same as the stretch ratio of the film in the first stretching step.
  • the method for producing an optical film is characterized by being 70 to 95% with respect to the total of the stretching ratio of the film in the third stretching step.
  • an optical film excellent in transparency, workability, and flatness can be produced even if an acrylic resin is contained in a cellulose ester resin.
  • the manufacturing method of the optical film which can be provided can be provided.
  • the film is whitened. It is considered that the strength of the film can be improved while suppressing the occurrence of the above. This is considered to be because, when stretching is insufficient, the orientation of the resin constituting the film becomes insufficient. Moreover, when extending
  • the above range is a range in which the difference in the degree of orientation between the acrylic resin and the cellulose ester resin does not become too large while securing the orientation between the acrylic resin and the cellulose ester resin constituting the film to some extent. it is conceivable that.
  • the flatness can be improved while the transparency and workability of the obtained film are improved when the stretching ratio of the film in the first stretching step is within the above range.
  • the stretch ratio of the film in the first stretching step is too low, the stretch ratio of the film in the third stretching step becomes too high, and the film transport direction (longitudinal direction) during the third stretching step.
  • wrinkles vertical wrinkles
  • the stretch ratio of the film in the first stretching step is too high, the stretch ratio of the film in the third stretching step becomes too low, and the film is formed in the second stretching step and is perpendicular to the film transport direction. This is probably because wrinkles (lateral wrinkles) extending in the direction (short direction) tend not to be sufficiently removed even if they are stretched in the transport direction in the third stretching step.
  • planarity can be improved while improving the transparency and workability of the film obtained by defining the stretch ratio of the film in the first stretching step within the above range.
  • the sum total of the stretch ratio of the film in the said 1st extending process and the stretch ratio of the film in the said 3rd extending process is with respect to the total amount of the said acrylic resin and the said cellulose-ester resin.
  • the content of the acrylic resin is A mass%, it is preferably in the range of A / 3 + 15 to A / 5 + 30 in percentage.
  • the stretch ratio of the film in the first stretching step is the sum of the stretch ratio of the film in the first stretching step and the stretch ratio of the film in the third stretching step. It is preferably 80 to 95%.
  • an optical film having better flatness can be produced. This is considered to be due to the fact that the flatness can be further improved while improving the transparency and workability of the film obtained by defining the stretch ratio of the film in the first stretching step within the above range. It is done.
  • the atmospheric temperature in the first stretching step is 5 to 39 ° C.
  • the strength of the film can be further improved, and an optical film with better workability can be produced. This is considered to be because the resin constituting the film can be more suitably oriented in the first stretching step.
  • the first stretching step is a step of rotating while bringing a conveying roller into contact with the film peeled by the peeling step, and the surface temperature of the conveying roller is ⁇ 20 to It is preferably 0 ° C.
  • the strength of the film can be further improved, and an optical film with better workability can be produced. This is considered to be because the resin constituting the film can be more suitably oriented in the first stretching step.
  • another aspect of the present invention is an optical film obtained by the method for producing an optical film.
  • an optical film containing an acrylic resin in a cellulose ester resin which has excellent transparency, workability and flatness can get. And since it is excellent in a hygroscopic property, workability, etc., it can apply easily also to the protective film of the polarizing plate for liquid crystal display devices which enlarged the screen. Further, it can be easily cut into a desired size.
  • a polarizing plate including a polarizing element and a transparent protective film disposed on at least one surface of the polarizing element, wherein the transparent protective film is the optical film. It is a polarizing plate characterized by being.
  • an optical film excellent in moisture resistance, heat resistance, transparency, workability and flatness is applied as the transparent protective film of the polarizing plate.
  • a polarizing plate that can be suitably used for an apparatus is obtained. Specifically, even a polarizing plate for a liquid crystal display device having a large screen can suppress deformation due to moisture absorption. Moreover, since an optical film with favorable workability is used as the transparent protective film, the occurrence of damage is suppressed even when a large film is used.
  • Another aspect of the present invention is a liquid crystal display device including a liquid crystal cell and two polarizing plates arranged so as to sandwich the liquid crystal cell, and at least one of the two polarizing plates.
  • a liquid crystal display device characterized by being the polarizing plate.
  • a polarizing plate provided with an optical film excellent in moisture resistance, heat resistance, transparency, workability, and flatness is used, even if the screen is enlarged, the image display area It is possible to provide a liquid crystal display device in which the occurrence of defects in the optical film disposed is suppressed. Specifically, for example, even a liquid crystal display device with a large screen can suppress the occurrence of deformation due to moisture absorption of the optical film disposed in the image display area. In addition, since the processability of the optical film is good, even a large film that can be applied to a large-screen liquid crystal display device can suppress the occurrence of damage to the optical film during manufacturing. A screened liquid crystal display device can be provided.
  • an optical film excellent in transparency, workability, and planarity can be produced even when an acrylic resin is contained in a cellulose ester resin in order to improve moisture resistance, heat resistance, and the like.
  • a method for producing an optical film is provided.
  • the optical film obtained by the manufacturing method of the said optical film, the polarizing plate which used the said optical film as a transparent protective film, and the liquid crystal display device provided with the said polarizing plate are provided.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Health & Medical Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Polarising Elements (AREA)
  • Shaping By String And By Release Of Stress In Plastics And The Like (AREA)
  • Manufacture Of Macromolecular Shaped Articles (AREA)
  • Moulding By Coating Moulds (AREA)

Abstract

L'invention concerne un procédé de production d'un film optique selon un processus de formation de film par coulage de solution dans lequel une solution de résine contenant une résine acrylique et une résine d'ester de cellulose selon un rapport en masse de 95:5 à 30:70 est utilisée comme dopant, lequel procédé comprend : une première étape d'étirement dans laquelle un film séparé d'un corps de support est étiré par MD ; une seconde étape d'étirement dans laquelle le film étiré lors de la première étape d'étirement est étiré par TD ; une étape de coupe dans laquelle les deux parties d'extrémité du film étiré lors de la seconde étape d'étirement sont découpées ; et une troisième étape d'étirement dans laquelle le film, dont les parties d'extrémité découpées ont été supprimées, est étiré par MD. Si le contenu de la résine acrylique est représenté par A % en masse, le total du rapport d'étirement de la première étape d'étirement et du rapport d'étirement de la troisième étape d'étirement varie de A/3 + 10 à A/5 + 40 en pourcentage. Le rapport d'étirement de la première étape d'étirement représente 70-95% du rapport d'étirement total dans le sens d'usinage du film.
PCT/JP2011/001416 2010-03-24 2011-03-10 Procédé de production de film optique, film optique, plaque de polarisation et dispositif d'affichage à cristaux liquides Ceased WO2011118145A1 (fr)

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Cited By (2)

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Publication number Priority date Publication date Assignee Title
WO2014188993A1 (fr) * 2013-05-24 2014-11-27 コニカミノルタ株式会社 Procédé de production d'un film optique
EP3680281A4 (fr) * 2017-09-04 2021-06-02 Hyosung Chemical Corporation Film acrylique

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10076473B2 (en) * 2016-02-15 2018-09-18 C&Tech Corporation Apparatus and method for manufacturing dried gel sheet and gel sheet or beauty pack manufactured by the same

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JP2003098345A (ja) * 2001-09-20 2003-04-03 Konica Corp 偏光板、セルロースエステルフィルムおよびその製造方法
JP2004163981A (ja) * 2004-02-06 2004-06-10 Teijin Chem Ltd 位相差フィルムの製造方法
WO2009047924A1 (fr) * 2007-10-13 2009-04-16 Konica Minolta Opto, Inc. Film optique
JP2009292006A (ja) * 2008-06-04 2009-12-17 Konica Minolta Opto Inc 光学フィルム及び光学フィルムの製造方法
WO2009150910A1 (fr) * 2008-06-10 2009-12-17 コニカミノルタオプト株式会社 Procédé pour produire un film acrylique et film acrylique produit par le procédé de production

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Publication number Priority date Publication date Assignee Title
JP2003098345A (ja) * 2001-09-20 2003-04-03 Konica Corp 偏光板、セルロースエステルフィルムおよびその製造方法
JP2004163981A (ja) * 2004-02-06 2004-06-10 Teijin Chem Ltd 位相差フィルムの製造方法
WO2009047924A1 (fr) * 2007-10-13 2009-04-16 Konica Minolta Opto, Inc. Film optique
JP2009292006A (ja) * 2008-06-04 2009-12-17 Konica Minolta Opto Inc 光学フィルム及び光学フィルムの製造方法
WO2009150910A1 (fr) * 2008-06-10 2009-12-17 コニカミノルタオプト株式会社 Procédé pour produire un film acrylique et film acrylique produit par le procédé de production

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014188993A1 (fr) * 2013-05-24 2014-11-27 コニカミノルタ株式会社 Procédé de production d'un film optique
JPWO2014188993A1 (ja) * 2013-05-24 2017-02-23 コニカミノルタ株式会社 光学フィルムの製造方法
EP3680281A4 (fr) * 2017-09-04 2021-06-02 Hyosung Chemical Corporation Film acrylique

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