WO2016152381A1 - Procédé de production d'un film étiré obliquement - Google Patents

Procédé de production d'un film étiré obliquement Download PDF

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WO2016152381A1
WO2016152381A1 PCT/JP2016/055826 JP2016055826W WO2016152381A1 WO 2016152381 A1 WO2016152381 A1 WO 2016152381A1 JP 2016055826 W JP2016055826 W JP 2016055826W WO 2016152381 A1 WO2016152381 A1 WO 2016152381A1
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Prior art keywords
film
group
stretching
stretched film
obliquely stretched
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PCT/JP2016/055826
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English (en)
Japanese (ja)
Inventor
晋平 畠山
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コニカミノルタ株式会社
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Application filed by コニカミノルタ株式会社 filed Critical コニカミノルタ株式会社
Priority to JP2017507633A priority Critical patent/JP6903001B2/ja
Priority to CN201680016798.6A priority patent/CN107428070A/zh
Priority to KR1020177024621A priority patent/KR102024448B1/ko
Priority to CN202210287977.0A priority patent/CN114953408A/zh
Publication of WO2016152381A1 publication Critical patent/WO2016152381A1/fr

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C55/00—Shaping by stretching, e.g. drawing through a die; Apparatus therefor
    • B29C55/02—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
    • B29C55/04—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets uniaxial, e.g. oblique
    • B29C55/045—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets uniaxial, e.g. oblique in a direction which is not parallel or transverse to the direction of feed, e.g. oblique
    • 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
    • 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
    • B29C55/20—Edge clamps

Definitions

  • the present invention relates to a method for producing an obliquely stretched film in which the film is stretched in an oblique direction with respect to the width direction.
  • a self-luminous display device such as an organic EL (Electro-Luminescence) display device called OLED (Organic light-Emitting Diode) has attracted attention.
  • OLED Organic light-Emitting Diode
  • a reflector such as an aluminum plate is provided on the back side of the display in order to increase the light extraction efficiency. Therefore, external light incident on the display is reflected by the reflector to reduce the image contrast. .
  • a circularly polarizing plate is formed by laminating a stretched film and a polarizer, and this circularly polarizing plate is disposed on the surface side of the display. At this time, the circularly polarizing plate is formed by bonding the polarizer and the stretched film so that the in-plane slow axis of the stretched film is inclined at a desired angle with respect to the transmission axis of the polarizer.
  • a general polarizer (polarizing film) is obtained by stretching at a high magnification in the longitudinal direction, and its transmission axis coincides with the width direction.
  • the conventional retardation film is produced by longitudinal stretching or transverse stretching, and in principle, the in-plane slow axis is in the direction of 0 ° or 90 ° with respect to the longitudinal direction of the film.
  • the long polarizing film and / or the stretched film are cut out at a specific angle and the film pieces are separated from each other.
  • the batch method of bonding the sheets one by one had to be adopted, and the productivity was deteriorated.
  • the film is stretched in a desired angle direction (obliquely) with respect to the longitudinal direction, and the direction of the slow axis can be freely set to a direction that is neither 0 ° nor 90 ° with respect to the longitudinal direction of the film.
  • Various methods for producing a long and obliquely stretched film that can be controlled have been proposed.
  • the resin film is unwound from a direction different from the winding direction of the stretched film, and both ends of the resin film are gripped and transported by a pair of gripping tools. And the resin film is extended
  • the long diagonally stretched film which has a slow axis in the desired angle of more than 0 degrees and less than 90 degrees with respect to a longitudinal direction is manufactured.
  • FIG. 10 schematically shows a state in which an avalan-like residual stress T is generated in manufacturing an obliquely stretched film.
  • the film is passed through a preheating zone Z1 of a stretching machine and then obliquely stretched in the stretching zone Z2, and then the optical axis (slow axis) in the heat setting zone Z3.
  • the film stretched obliquely in the stretching zone Z2 is relatively more than the gripping tool side (delay side) that travels relatively delayed among the pair of gripping tools that grip both ends of the width direction of the film. Since the gripping tool side (leading side) traveling in advance enters the heat setting zone Z3 first, the film shrinkage starts from the leading side. For this reason, as shown in the figure, an avalan-like residual stress T is generated in the order of the leading side, the center in the width direction, and the delay side.
  • FIG. 11 schematically shows a state in which an avalan-like residual stress T is generated when the film is widened in the stretching zone Z2.
  • the film By widening the film in the stretching zone Z2, the film extends in the width direction, so that the film does not shrink in the stretching zone Z2, and therefore no loose residual stress is generated during the oblique stretching.
  • the film shrinks from the leading side, and as in the case of FIG. Residual stress T is generated.
  • an object of the present invention is to provide a method for producing an obliquely stretched film that can suppress the occurrence of an avalan residual stress after oblique stretching.
  • one gripping tool is relatively advanced while the other gripping tool is relatively positioned while gripping both ends in the width direction of the film with a pair of gripping tools.
  • the heat setting step widening the obliquely stretched film after the oblique stretching step is completed, With the width of the obliquely stretched film before widening after the end of oblique stretching as L1, in the heat setting step, the width was widened to the leading side and the delay side from the portion corresponding to the width L1 of the obliquely stretched film before widening.
  • the widths of the portions are L2 and L3
  • the obliquely stretched film is widened, and the film is pulled in the width direction, so that it is possible to suppress the occurrence of loose residual stress on the film after the oblique stretching.
  • a circularly polarizing plate is formed using the manufactured obliquely stretched film, and even if this circularly polarizing plate is applied to an OLED and the OLED is placed in a different temperature and humidity environment, the above-described avalan-like residual stress is obtained. It is possible to suppress the occurrence of oblique stripe-like display unevenness.
  • conditional expression (1) it is possible to suppress the occurrence of an avalan-like residual stress without substantially changing the direction of the optical axis (slow axis) oriented in a predetermined direction by oblique stretching. Can do. Therefore, even if the film is widened in the heat setting step after oblique stretching, an obliquely stretched film having desired orientation characteristics can be obtained by fixing the optical axis in a predetermined direction.
  • the numerical value range includes the values of the lower limit A and the upper limit B.
  • the method for producing a long obliquely stretched film according to the present embodiment is a method for producing a long obliquely stretched film by stretching a long original fabric film containing a thermoplastic resin in an oblique direction with respect to the width direction and the longitudinal direction. This is a method for producing a long obliquely stretched film.
  • the orientation direction of the long obliquely stretched film is an angle of more than 0 ° and less than 90 ° with respect to the width direction of the film in the film plane (in the plane perpendicular to the thickness direction).
  • the direction automatically forms an angle of more than 0 ° and less than 90 ° with respect to the longitudinal direction of the film). Since the slow axis is usually expressed in the stretching direction or a direction perpendicular to the stretching direction, the slow axis has such a slow axis by stretching in a direction of more than 0 ° and less than 90 ° with respect to the width direction of the film.
  • a long diagonally stretched film can be produced.
  • the angle formed by the width direction of the long obliquely stretched film and the slow axis that is, the orientation angle, can be arbitrarily set to a desired angle in the range of more than 0 ° and less than 90 °.
  • the long length refers to a film having a length of at least about 5 times the width of the film, preferably a length of 10 times or more, specifically a roll shape. It is possible to consider one having a length (film roll) that is wound around and stored or transported.
  • a long diagonally stretched film is formed by forming a long unoriented film and then winding it around a core to form a wound body (raw film), and the raw film is obliquely stretched from the wound body.
  • the film may be supplied and manufactured, or may be continuously supplied from the film forming process to the oblique stretching process without winding the long film after film formation. Continuously performing the film forming step and the oblique stretching step can feed back the film thickness and optical value results of the stretched film to change the film forming conditions to obtain a desired long obliquely stretched film. It is preferable because it is possible.
  • the long diagonally stretched film of desired length can be obtained by manufacturing a long diagonally stretched film continuously.
  • thermoplastic resin contained in the raw film alicyclic olefin polymer resin (COP), polycarbonate resin (PC), cellulose ester resin and the like can be used.
  • COP alicyclic olefin polymer resin
  • PC polycarbonate resin
  • cellulose ester resin and the like can be used as the thermoplastic resin contained in the raw film.
  • the cellulose ester-based resin easily absorbs moisture, and the orientation angle ⁇ is likely to vary due to humidity fluctuations associated with long-term use. Therefore, this embodiment suppresses the variation in the orientation angle ⁇ in the width direction of the obliquely stretched film. The effect will be greater.
  • the obliquely stretched film obtained by obliquely stretching the above-described raw film can be applied to a liquid crystal display device that can be visually recognized by wearing polarized sunglasses. That is, a circularly polarizing plate is constructed by further bonding an obliquely stretched film on the viewing side of the polarizer of the polarizing plate on the viewing side with respect to the liquid crystal layer. At this time, they are bonded together so that the slow axis of the obliquely stretched film and the transmission axis of the polarizer are 45 °.
  • the linearly polarized light emitted from the liquid crystal layer and transmitted through the viewer-side polarizer is converted into circularly polarized light by the obliquely stretched film (functioning as QWP). Therefore, when an observer wears polarized sunglasses and observes the display image of the liquid crystal display device, the polarization sunglasses and the transmission axes of the polarized sunglasses are not limited to any angle.
  • a display image can be observed by guiding a light component parallel to the transmission axis to the eyes of the observer. Therefore, it is possible to suppress the display image from becoming difficult to see depending on the viewing angle (depending on the direction of the transmission axis of the polarized sunglasses).
  • a cellulose ester-based resin film used for the raw fabric film of the present embodiment a cellulose acylate satisfying the following formulas (1) and (2) is contained, and a compound represented by the following general formula (A) is used.
  • the thing to contain is mentioned.
  • Formula (1) 2.0 ⁇ Z1 ⁇ 3.0
  • Formula (2) 0 ⁇ X ⁇ 3.0 In formulas (1) and (2), Z1 represents the total acyl substitution degree of cellulose acylate, and X represents the sum of the propionyl substitution degree and butyryl substitution degree of cellulose acylate.
  • L 1 and L 2 each independently represent a single bond or a divalent linking group.
  • L 1 and L 2 include the following structures. (The following R represents a hydrogen atom or a substituent.)
  • L 1 and L 2 are preferably —O—, —COO—, and —OCO—.
  • R 1 , R 2 and R 3 each independently represent a substituent.
  • substituent represented by R 1 , R 2 and R 3 include a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom, etc.), alkyl group (methyl group, ethyl group, n-propyl group, Isopropyl group, tert-butyl group, n-octyl group, 2-ethylhexyl group, etc.), cycloalkyl group (cyclohexyl group, cyclopentyl group, 4-n-dodecylcyclohexyl group, etc.), alkenyl group (vinyl group, allyl group, etc.) , Cycloalkenyl groups (2-cyclopenten-1-yl, 2-cyclohexen-1-yl group, etc.), alkynyl groups (ethynyl group, propargyl group, etc.),
  • R 1 and R 2 are preferably a substituted or unsubstituted phenyl group, a substituted or unsubstituted cyclohexyl group, more preferably a substituted phenyl group or a substituted cyclohexyl group, Preferred are a phenyl group having a substituent at the 4-position and a cyclohexyl group having a substituent at the 4-position.
  • R 3 is preferably a hydrogen atom, halogen atom, alkyl group, alkenyl group, aryl group, heterocyclic group, hydroxyl group, carboxyl group, alkoxy group, aryloxy group, acyloxy group, cyano group, amino group, More preferably, they are a hydrogen atom, a halogen atom, an alkyl group, a cyano group, and an alkoxy group.
  • Wa and Wb represent a hydrogen atom or a substituent, (I) Wa and Wb may be bonded to each other to form a ring; (II) At least one of Wa and Wb may have a ring structure, or (III) At least one of Wa and Wb may be an alkenyl group or an alkynyl group.
  • substituent represented by Wa and Wb include halogen atoms (fluorine atom, chlorine atom, bromine atom, iodine atom, etc.), alkyl groups (methyl group, ethyl group, n-propyl group, isopropyl group, tert- Butyl group, n-octyl group, 2-ethylhexyl group, etc.), cycloalkyl group (cyclohexyl group, cyclopentyl group, 4-n-dodecylcyclohexyl group, etc.), alkenyl group (vinyl group, allyl group, etc.), cycloalkenyl group ( 2-cyclopenten-1-yl, 2-cyclohexen-1-yl group, etc.), alkynyl group (ethynyl group, propargyl group etc.), aryl group (phenyl group, p-tolyl group, naphthyl group etc.),
  • the ring is preferably a nitrogen-containing 5-membered ring or a sulfur-containing 5-membered ring.
  • the general formula (A) is particularly preferably a compound represented by the following general formula (1) or general formula (2).
  • a 1 and A 2 each independently represent —O—, —S—, —NRx— (Rx represents a hydrogen atom or a substituent) or —CO—.
  • Rx represents a hydrogen atom or a substituent
  • the example of the substituent represented by Rx is synonymous with the specific example of the substituent represented by said Wa and Wb.
  • Rx is preferably a hydrogen atom, an alkyl group, an aryl group, or a heterocyclic group.
  • X represents a nonmetallic atom belonging to Groups 14-16.
  • X is preferably ⁇ O, ⁇ S, ⁇ NRc, ⁇ C (Rd) Re.
  • Rc, Rd, and Re represent substituents, and examples thereof are synonymous with specific examples of the substituents represented by Wa and Wb.
  • L 1, L 2, R 1 , R 2, R 3, n is L 1, L 2, R 1 , same meanings as R 2, R 3, n in the general formula (A).
  • Q 1 is -O -, - S -, - NRy- (Ry represents a hydrogen atom or a substituent), - CRaRb- (Ra and Rb represents a hydrogen atom or a substituent), or Represents —CO—.
  • Ry, Ra, and Rb represent substituents, and examples thereof are synonymous with the specific examples of the substituents represented by Wa and Wb.
  • Y represents a substituent.
  • substituent represented by Y it is synonymous with the specific example of the substituent represented by said Wa and Wb.
  • Y is preferably an aryl group, a heterocyclic group, an alkenyl group, or an alkynyl group.
  • Examples of the aryl group represented by Y include a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, and a biphenyl group.
  • a phenyl group and a naphthyl group are preferable, and a phenyl group is more preferable.
  • heterocyclic group examples include heterocyclic groups containing at least one hetero atom such as a nitrogen atom, an oxygen atom, a sulfur atom such as a furyl group, a pyrrolyl group, a thienyl group, a pyridinyl group, a thiazolyl group, and a benzothiazolyl group.
  • a heterocyclic group containing at least one hetero atom such as a nitrogen atom, an oxygen atom, a sulfur atom such as a furyl group, a pyrrolyl group, a thienyl group, a pyridinyl group, a thiazolyl group, and a benzothiazolyl group.
  • Group, pyrrolyl group, thienyl group, pyridinyl group and thiazolyl group are preferred.
  • aryl groups or heterocyclic groups may have at least one substituent.
  • substituents include a halogen atom, an alkyl group having 1 to 6 carbon atoms, a cyano group, a nitro group, an alkylsulfinyl group having 1 to 6 carbon atoms, an alkylsulfonyl group having 1 to 6 carbon atoms, a carboxyl group, and 1 carbon atom.
  • 1 to 6 fluoroalkyl groups 1 to 6 carbon atoms alkoxy groups, 1 to 6 carbon atoms alkylthio groups, 1 to 6 carbon atoms N-alkylamino groups, 2 to 12 carbon atoms N, N-dialkylamino groups And an N-alkylsulfamoyl group having 1 to 6 carbon atoms and an N, N-dialkylsulfamoyl group having 2 to 12 carbon atoms.
  • L 1, L 2, R 1 , R 2, R 3, n is L 1, L 2, R 1 , same meanings as R 2, R 3, n in the general formula (A).
  • Q 3 represents ⁇ N— or ⁇ CRz— (Rz represents a hydrogen atom or a substituent), and Q 4 represents a nonmetallic atom belonging to Groups 14-16.
  • Z represents a nonmetallic atom group forming a ring together with Q 3 and Q 4 .
  • the ring formed from Q 3 , Q 4 and Z may be condensed with another ring.
  • the ring formed from Q 3 , Q 4 and Z is preferably a nitrogen-containing 5-membered or 6-membered ring condensed with a benzene ring.
  • L 1, L 2, R 1 , R 2, R 3, n is L 1, L 2, R 1 , same meanings as R 2, R 3, n in the general formula (A).
  • Wa and Wb are preferably a vinyl group having a substituent or an ethynyl group.
  • the compound represented by general formula (3) is particularly preferable.
  • the compound represented by the general formula (3) is superior in heat resistance and light resistance to the compound represented by the general formula (1), and is an organic solvent compared to the compound represented by the general formula (2).
  • the solubility with respect to and the compatibility with a polymer are favorable.
  • the compound represented by the general formula (A) can be contained by appropriately adjusting the amount for imparting desired wavelength dispersibility and anti-bleeding property.
  • the content is preferably 1 to 15% by mass, and particularly preferably 2 to 10% by mass. If it is in this range, sufficient wavelength dispersibility and bleeding prevention property can be imparted to the cellulose derivative.
  • general formula (A), general formula (1), general formula (2), and general formula (3) can be obtained by referring to known methods. Specifically, it can be synthesized with reference to Journal of Chemical Crystallography (1997); 27 (9); 512-526), JP2010-31223, JP2008-107767, and the like.
  • the cellulose acylate film according to this embodiment contains cellulose acylate as a main component.
  • the cellulose acylate film according to this embodiment preferably contains cellulose acylate in the range of 60 to 100% by mass with respect to the total mass (100% by mass) of the film.
  • the total acyl group substitution degree of cellulose acylate is 2.0 or more and less than 3.0, and more preferably 2.2 to 2.7.
  • cellulose acylate examples include esters of cellulose and aliphatic carboxylic acids and / or aromatic carboxylic acids having about 2 to 22 carbon atoms, and in particular, esters of cellulose and lower fatty acids having 6 or less carbon atoms. Preferably there is.
  • the acyl group bonded to the hydroxyl group of cellulose may be linear or branched, and may form a ring. Furthermore, another substituent may be substituted.
  • the degree of substitution is the same, birefringence decreases when the number of carbon atoms described above is large. Therefore, the number of carbon atoms is preferably selected from acyl groups having 2 to 6 carbon atoms.
  • the degree of propionyl substitution and the degree of butyryl substitution are preferred. Is a sum of 0 or more and less than 3.0.
  • the cellulose acylate preferably has 2 to 4 carbon atoms, more preferably 2 to 3 carbon atoms.
  • cellulose acylate includes propionate group, butyrate group or phthalyl group in addition to acetyl group such as cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate propionate butyrate or cellulose acetate phthalate.
  • Bound cellulose mixed fatty acid esters can be used.
  • the butyryl group forming butyrate may be linear or branched.
  • cellulose acetate, cellulose acetate butyrate, or cellulose acetate propionate is particularly preferably used as the cellulose acylate.
  • the cellulose acylate preferably satisfies the following mathematical formulas (i) and (ii) at the same time.
  • Y represents the degree of substitution of the acetyl group
  • X represents the degree of substitution of the propionyl group or butyryl group or a mixture thereof.
  • the mixing ratio is preferably 1:99 to 99: 1 (mass ratio).
  • cellulose acetate propionate is particularly preferably used as the cellulose acylate.
  • cellulose acetate propionate 0 ⁇ Y ⁇ 2.5 and 0.5 ⁇ X ⁇ 3.0 (where 2.0 ⁇ X + Y ⁇ 3.0) are preferable, and 0 More preferably, 0.5 ⁇ Y ⁇ 2.0 and 1.0 ⁇ X ⁇ 2.0 (where 2.0 ⁇ X + Y ⁇ 3.0).
  • the degree of substitution of acyl groups can be measured according to ASTM-D817-96, which is one of the standards formulated and issued by ASTM (American Society for Testing and Materials).
  • the number average molecular weight of cellulose acylate is preferably in the range of 60,000 to 300,000, since the mechanical strength of the resulting film becomes strong. More preferably, cellulose acylate having a number average molecular weight of 70,000 to 200,000 is used.
  • the weight average molecular weight (Mw) and number average molecular weight (Mn) of cellulose acylate are measured using gel permeation chromatography (GPC).
  • the measurement conditions are as follows.
  • this measuring method can be used also as a measuring method of the other polymer in this embodiment.
  • the residual sulfuric acid content in the cellulose acylate is preferably in the range of 0.1 to 45 mass ppm in terms of elemental sulfur. These are considered to be contained in the form of salts. If the residual sulfuric acid content exceeds 45 ppm by mass, there is a tendency to break during hot stretching or slitting after hot stretching.
  • the residual sulfuric acid content is more preferably in the range of 1 to 30 ppm by mass.
  • the residual sulfuric acid content can be measured by the method prescribed in ASTM-D817-96.
  • the free acid content in the cellulose acylate is preferably 1 to 500 ppm by mass.
  • the above range is preferable because it is difficult to break as described above.
  • the free acid content is preferably in the range of 1 to 100 ppm by mass, and is more difficult to break.
  • the range of 1 to 70 mass ppm is particularly preferable.
  • the free acid content can be measured by the method prescribed in ASTM-D817-96.
  • the residual alkaline earth metal content, residual sulfuric acid content, and residual acid content are within the above ranges. And is preferable.
  • cellulose as a raw material for cellulose acylate, but examples include cotton linters, wood pulp, and kenaf. Moreover, the cellulose acylate obtained from them can be mixed and used at an arbitrary ratio.
  • Cellulose acylate can be produced by a known method. Specifically, for example, it can be synthesized with reference to the method described in JP-A-10-45804.
  • cellulose acylate is also affected by trace metal components in cellulose acylate.
  • trace metal components are considered to be related to water used in the production process, but it is preferable that there are few components that can become insoluble nuclei.
  • metal ions such as iron, calcium and magnesium may form an insoluble matter by forming a salt with a polymer decomposition product or the like which may contain an organic acidic group, and it is preferable that the amount of the metal ion is small.
  • the calcium (Ca) component easily forms a coordination compound (that is, a complex) with an acidic component such as a carboxylic acid or a sulfonic acid, and many ligands. Insoluble starch, turbidity) may be formed, so it is preferable that the amount be small.
  • the content in cellulose acylate is preferably 1 mass ppm or less.
  • the content in the cellulose acylate is preferably 60 ppm by mass or less, more preferably 0 to 30 ppm by mass.
  • the magnesium (Mg) component too much content will cause insoluble matter, so the content in the cellulose acylate is preferably 0 to 70 ppm by mass, particularly preferably 0 to 20 ppm by mass. .
  • the content of metal components such as the content of iron (Fe) component, the content of calcium (Ca) component, the content of magnesium (Mg) component, etc.
  • ICP-AES Inductively Coupled Plasma Atomic Emission Spectrometer
  • alicyclic olefin polymer resin examples include cyclic olefin random multi-component copolymers described in JP-A No. 05-310845 and JP-A No. 05-97978.
  • the hydrogenated polymer, the thermoplastic dicyclopentadiene ring-opening polymer described in JP-A No. 11-124429, the hydrogenated product thereof, and the like can be employed.
  • the alicyclic olefin polymer resin is a polymer having an alicyclic structure such as a saturated alicyclic hydrocarbon (cycloalkane) structure or an unsaturated alicyclic hydrocarbon (cycloalkene) structure.
  • the number of carbon atoms constituting the alicyclic structure is not particularly limited, but when it is usually in the range of 4 to 30, preferably 5 to 20, more preferably 5 to 15, the mechanical strength, The properties of heat resistance and formability of the long film are highly balanced and suitable.
  • the proportion of the repeating unit containing the alicyclic structure in the alicyclic olefin polymer may be appropriately selected, but is preferably 55% by weight or more, more preferably 70% by weight or more, and particularly preferably 90% by weight. That's it.
  • the ratio of the repeating unit having an alicyclic structure in the alicyclic polyolefin resin is within this range, the transparency and heat resistance of an optical material such as a retardation film obtained from the long obliquely stretched film of the present embodiment are improved. Since it improves, it is preferable.
  • olefin polymer resin having an alicyclic structure examples include norbornene resins, monocyclic olefin resins, cyclic conjugated diene resins, vinyl alicyclic hydrocarbon resins, and hydrides thereof.
  • norbornene-based resins can be suitably used because of their good transparency and moldability.
  • Examples of the norbornene-based resin include a ring-opening polymer of a monomer having a norbornene structure, a ring-opening copolymer of a monomer having a norbornene structure and another monomer, a hydride thereof, and a norbornene structure. And an addition copolymer of a monomer having a norbornene structure and an addition copolymer of another monomer or a hydride thereof.
  • a ring-opening (co) polymer hydride of a monomer having a norbornene structure is particularly suitable from the viewpoints of transparency, moldability, heat resistance, low hygroscopicity, dimensional stability and lightness. Can be used.
  • melt extrusion method As a method for forming a long film (raw film) using the norbornene-based resin as described above, a solution casting method or a melt extrusion method is preferred.
  • melt extrusion method include an inflation method using a die, but a method using a T die is preferable in terms of excellent productivity and thickness accuracy.
  • a sheet-like thermoplastic resin extruded from a die is brought into close contact with a cooling drum under a pressure of 50 kPa or less; 2) melting When producing a long film by extrusion, the enclosure member covers from the die opening to the first cooling drum that is in close contact, and the distance from the enclosure member to the die opening or the first contact cooling drum is 100 mm or less.
  • Method 3 Method of heating the temperature of the atmosphere within 10 mm to a specific temperature from the sheet-like thermoplastic resin extruded from the die opening when producing a long film by the melt extrusion method; A sheet-like thermoplastic resin extruded from a die so as to satisfy the above condition is taken into close contact with a cooling drum under a pressure of 50 kPa or less; A method in which a wind having a speed difference of 0.2 m / s or less from the cooling speed of the cooling drum that is first brought into close contact with the sheet-like thermoplastic resin extruded from the die opening is produced. It is done.
  • This long film may be a single layer or a laminated film of two or more layers.
  • the laminated film can be obtained by a known method such as a coextrusion molding method, a co-casting molding method, a film lamination method, or a coating method. Of these, the coextrusion molding method and the co-casting molding method are preferable.
  • Polycarbonate resin As the polycarbonate resin used for the raw film of the present embodiment, various resins can be used without particular limitation.
  • An aromatic polycarbonate resin is preferable from the viewpoint of chemical properties and physical properties, and a bisphenol A polycarbonate resin is particularly preferable.
  • those using a bisphenol A derivative in which a benzene ring, a cyclohexane ring, an aliphatic hydrocarbon group and the like are introduced into bisphenol A are more preferable.
  • a polycarbonate resin having a structure in which the anisotropy in the unit molecule is reduced, obtained by using a derivative in which the functional group is introduced asymmetrically with respect to the central carbon of bisphenol A is particularly preferable.
  • a polycarbonate resin for example, two methyl groups in the center carbon of bisphenol A are replaced by benzene rings, and one hydrogen of each benzene ring of bisphenol A is centered by a methyl group or a phenyl group.
  • a polycarbonate resin obtained by using an asymmetrically substituted carbon is particularly preferable.
  • 4,4′-dihydroxydiphenylalkane or a halogen-substituted product thereof can be obtained by a phosgene method or a transesterification method.
  • 4,4′-dihydroxydiphenylmethane, 4,4′-dihydroxydiphenyl Examples include ethane and 4,4'-dihydroxydiphenylbutane.
  • JP 2006-215465 A, JP 2006-91836 A, JP 2005-121813 A, JP 2003-167121 A, JP 2009-126128 A, JP Examples thereof include polycarbonate resins described in 2012-31369, JP 2012-67300 A, International Publication No. 00/26705, and the like.
  • the polycarbonate resin may be used by mixing with a transparent resin such as polystyrene resin, methyl methacrylate resin, and cellulose acetate resin. Moreover, you may laminate
  • the polycarbonate-based resin preferably has a glass transition point (Tg) of 110 ° C. or higher and a water absorption (a value measured under conditions of 23 ° C. water and 24 hours) of 0.3% or less. Moreover, Tg is 120 degreeC or more, and a water absorption rate is 0.2% or less more preferable.
  • Tg glass transition point
  • water absorption a value measured under conditions of 23 ° C. water and 24 hours
  • the polycarbonate-based resin film that can be used in the present embodiment can be formed by a known method, and among them, the solution casting method and the melt casting method are preferable.
  • the raw film of this embodiment may contain an additive.
  • the additive include a plasticizer, an ultraviolet absorber, a retardation adjusting agent, an antioxidant, a deterioration preventing agent, a peeling aid, a surfactant, a dye, and fine particles.
  • additives other than the fine particles may be added when preparing the dope solution, or may be added when preparing the fine particle dispersion.
  • plasticizer examples include phthalate ester, fatty acid ester, trimellitic ester, phosphate ester, polyester, sugar ester, and acrylic polymer. Among these, from the viewpoint of moisture permeability, polyester-based and sugar ester-based polymer plasticizers are preferably used.
  • Polyester plasticizers are superior in non-migration and extraction resistance compared to phthalate ester plasticizers such as dioctyl phthalate. It can be applied to a wide range of uses by selecting or using these plasticizers according to the use.
  • the acrylic polymer is preferably a homopolymer or copolymer of acrylic acid or methacrylic acid alkyl ester.
  • acrylate monomer examples include methyl acrylate, ethyl acrylate, propyl acrylate (i-, n-), butyl acrylate (n-, i-, s-, t-), pentyl acrylate ( n-, i-, s-), hexyl acrylate (n-, i-), heptyl acrylate (n-, i-), octyl acrylate (n-, i-), nonyl acrylate (n-, i-), myristyl acrylate (n-, i-), acrylic acid (2-ethylhexyl), acrylic acid ( ⁇ -caprolactone), acrylic acid (2-hydroxyethyl), acrylic acid (2-hydroxypropyl), acrylic Acid (3-hydroxypropyl), acrylic acid (4-hydroxybutyl), acrylic acid (2-hydroxybutyl), acrylic acid (2-methoxyethyl), acrylic acid 2-ethoxyethyl), etc., or
  • the acrylic polymer is a homopolymer or copolymer of the above-mentioned monomers, but the acrylic acid methyl ester monomer unit preferably has 30% by mass or more, and the methacrylic acid methyl ester monomer unit has 40% by mass or more. preferable. In particular, a homopolymer of methyl acrylate or methyl methacrylate is preferred.
  • the polyester plasticizer is a reaction product of a monovalent or tetravalent carboxylic acid and a monovalent or hexavalent alcohol, and is mainly obtained by reacting a divalent carboxylic acid with a glycol.
  • Representative divalent carboxylic acids include glutaric acid, itaconic acid, adipic acid, phthalic acid, azelaic acid, sebacic acid and the like.
  • the polyester plasticizer is preferably an aromatic terminal ester plasticizer.
  • an ester compound having a structure obtained by reacting phthalic acid, adipic acid, at least one benzene monocarboxylic acid and at least one alkylene glycol having 2 to 12 carbon atoms is preferable. As long as it has an adipic acid residue and a phthalic acid residue as the final compound structure, it may be reacted as an acid anhydride or esterified product of a dicarboxylic acid when an ester compound is produced.
  • benzene monocarboxylic acid component examples include benzoic acid, para-tert-butylbenzoic acid, orthotoluic acid, metatoluic acid, p-toluic acid, dimethylbenzoic acid, ethylbenzoic acid, normal propylbenzoic acid, aminobenzoic acid, acetoxybenzoic acid and the like. Most preferred is benzoic acid. Moreover, these can each be used as a 1 type, or 2 or more types of mixture.
  • alkylene glycol component having 2 to 12 carbon atoms examples include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,2-propanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 2,2-diethyl-1 , 3-propanediol (3,3-dimethylolpentane), 2-n-butyl-2-ethyl-1,3-propanediol (3,3-dimethylolheptane), 3-methyl-1,5-pentane Diol, 1,6-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-
  • the aromatic terminal ester plasticizer may be either an oligoester type or a polyester type, and the molecular weight is preferably in the range of 100 to 10,000, but is preferably in the range of 350 to 3000.
  • the acid value is 1.5 mgKOH / g or less, the hydroxy (hydroxyl group) value is 25 mgKOH / g or less, more preferably the acid value is 0.5 mgKOH / g or less, and the hydroxy (hydroxyl group) value is 15 mgKOH / g or less.
  • the sugar ester compound is an ester other than a cellulose ester, and is a compound obtained by esterifying all or part of the OH group of a sugar such as the following monosaccharide, disaccharide, trisaccharide or oligosaccharide. Specific examples thereof include a compound represented by the general formula (4).
  • R 1 to R 8 represent a hydrogen atom, a substituted or unsubstituted alkylcarbonyl group having 2 to 22 carbon atoms, or a substituted or unsubstituted arylcarbonyl group having 2 to 22 carbon atoms.
  • R 1 to R8 may be the same or different.
  • plasticizers are preferably added in an amount of 0.5 to 30 parts by mass with respect to 100 parts by mass of the cellulose ester film.
  • Retardation adjuster As a compound to be added for adjusting the retardation, an aromatic compound having two or more aromatic rings as described in the specification of European Patent 911,656A2 can be used.
  • the aromatic ring of the aromatic compound particularly preferably contains an aromatic hetero ring in addition to the aromatic hydrocarbon ring.
  • the aromatic heterocycle is generally an unsaturated heterocycle. Of these, a 1,3,5-triazine ring is particularly preferred.
  • the raw film of this embodiment has a cellulose ester and a substituent selected from a carboxyl group, a hydroxyl group, an amino group, an amide group, and a sulfonic acid group, and has a weight average molecular weight of 500 to 200,000. It is preferable to contain a polymer or oligomer of a vinyl compound within the range.
  • the mass ratio of the content of the cellulose ester and the polymer or oligomer is preferably in the range of 95: 5 to 50:50.
  • fine particles can be contained in the original film as a matting agent, thereby facilitating the conveyance and winding of the original film and a long obliquely stretched film produced using the original film. Can do.
  • the particle size of the matting agent is preferably primary particles or secondary particles of 10 nm to 0.1 ⁇ m.
  • a substantially spherical matting agent having a primary particle acicular ratio of 1.1 or less is preferably used.
  • the fine particles those containing silicon are preferable, and silicon dioxide is particularly preferable.
  • silicon dioxide is particularly preferable.
  • silicon dioxide for example, Aerosil R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, TT600 (manufactured by Nippon Aerosil Co., Ltd.) manufactured by Nippon Aerosil Co., Ltd.
  • commercially available products such as Aerosil 200V, R972, R972V, R974, R202, and R812 can be preferably used.
  • the polymer fine particles include silicone resin, fluorine resin, and acrylic resin. Silicone resins are preferred, and those having a three-dimensional network structure are particularly preferred. Examples of such resins include Tospearl 103, 105, 108, 120, 145, 3120, and 240 (manufactured by Toshiba Silicone Co., Ltd.).
  • the fine silicon dioxide particles preferably have a primary average particle diameter of 20 nm or less and an apparent specific gravity of 70 g / L or more.
  • the average diameter of the primary particles is more preferably 5 to 16 nm, and further preferably 5 to 12 nm. A smaller primary particle average diameter is preferred because haze is low.
  • the apparent specific gravity is preferably 90 to 200 g / L or more, and more preferably 100 to 200 g / L or more. Higher apparent specific gravity makes it possible to produce a high-concentration fine particle dispersion, which is preferable because no haze or aggregates are generated.
  • the addition amount of the matting agent in this embodiment is preferably 0.01 to 1.0 g, more preferably 0.03 to 0.3 g, and still more preferably 0.08 to 0.16 g per 1 m 2 of the raw film.
  • heat stabilizers such as inorganic fine particles such as kaolin, talc, diatomaceous earth, quartz, calcium carbonate, barium sulfate, titanium oxide, and alumina, and alkaline earth metal salts such as calcium and magnesium may be added.
  • a surfactant, a peeling accelerator, an antistatic agent, a flame retardant, a lubricant, an oil agent and the like may be added.
  • the tension softening point of the raw film is preferably 105 ° C. to 145 ° C. in order to exhibit sufficient heat resistance, and particularly preferably 110 ° C. to 130 ° C.
  • a sample film is cut out at 120 mm (length) ⁇ 10 mm (width) and pulled with a tension of 10 N.
  • the temperature can be continuously increased at a temperature increase rate of 30 ° C./min, and the temperature at 9 N can be measured three times, and the average value can be obtained.
  • the dimensional change rate (%) of the obliquely stretched film is preferably less than 0.5%, and more preferably less than 0.3%.
  • the raw film of this embodiment preferably has few defects in the film.
  • the defect is a void in the film (foaming defect) generated due to the rapid evaporation of the solvent in the drying process of the solution casting, a foreign matter in the film forming stock solution, or a foreign matter mixed in the film forming. This refers to the foreign matter (foreign matter defect) in the film.
  • a defect having a diameter of 5 ⁇ m or more in the film plane is 1/10 cm square or less. More preferably, it is 0.5 piece / 10 cm square or less, more preferably 0.1 piece / 10 cm square or less.
  • the diameter of the above defect indicates the diameter when the defect is circular, and when the defect is not circular, the range of the defect is determined by observing with a microscope according to the following method, and the maximum diameter (diameter of circumscribed circle) is determined.
  • the range of the defect is the size of the shadow when the defect is observed with the transmitted light of the differential interference microscope when the defect is a bubble or a foreign object.
  • the defect is a change in the surface shape, such as transfer of a roll flaw or an abrasion
  • the size is confirmed by observing the defect with the reflected light of a differential interference microscope.
  • the film When the number of defects is more than 1/10 cm square, for example, when a tension is applied to the film during processing in a later process, the film may be broken with the defect as a starting point and productivity may be reduced. Moreover, when the diameter of a defect becomes 5 micrometers or more, it can confirm visually by polarizing plate observation etc., and when used as an optical member, a bright spot may arise.
  • the raw film of this embodiment preferably has a total light transmittance of 90% or more, more preferably 93% or more.
  • the practical upper limit of the total light transmittance is about 99%.
  • reduce the surface roughness of the film surface by reducing the surface roughness of the film contact part (cooling roll, calender roll, drum, belt, coating substrate in solution casting, transport roll, etc.) during film formation. It is effective to reduce the diffusion and reflection of light on the film surface.
  • the raw film of this embodiment containing the resin described above can be formed by either the solution casting film forming method or the melt casting film forming method described below.
  • a raw fabric film contains a cellulose ester-based resin will be described here, the same applies to a case where another resin is included.
  • a dope which is a raw material solution of a cellulose ester resin raw film
  • the dope film that is, the web formed on the support by casting is peeled off by a peeling roll when it has made a full turn on the support.
  • the peeled web (film) is then introduced into a stretching device comprising a tenter.
  • the polymer is melted at a temperature capable of melting, and extruded from the T die into a film shape (sheet shape) on a cooling drum, Cool and solidify and peel the film from the cooling drum. Then, the peeled film is introduced into a stretching apparatus composed of a tenter.
  • the solid content concentration of the dope which is a cellulose ester solution is usually about 10 to 40% by mass, and the dope viscosity at the time of casting in the casting step is 1 to 200. Prepared with a range of poises.
  • the dissolution of the cellulose ester is usually performed by means such as a stirring dissolution method, a heating dissolution method, an ultrasonic dissolution method, etc. in a dissolution vessel, and the pressure is higher than the boiling point of the solvent at normal pressure.
  • a method in which the solvent is heated at a temperature at which it does not boil and is dissolved while stirring is more preferable because it prevents the formation of a massive undissolved material called gel or maco.
  • a cooling dissolution method described in JP-A-9-95538 or a method of dissolving under high pressure described in JP-A-11-21379 may be used.
  • a method in which the cellulose ester is mixed with a poor solvent and wetted or swollen, and then mixed with a good solvent and dissolved is also preferably used.
  • an apparatus for mixing or dissolving cellulose ester with a poor solvent and an apparatus for mixing and dissolving with a good solvent may be separately provided.
  • the type of the pressure vessel used for dissolving the cellulose ester is not particularly limited as long as it can withstand a predetermined pressure and can be heated and stirred under pressure.
  • instruments such as a pressure gauge and a thermometer are appropriately disposed in the pressurized container.
  • the pressurization may be performed by a method of injecting an inert gas such as nitrogen gas or by increasing the vapor pressure of the solvent by heating. Heating is preferably performed from the outside.
  • a jacket type is preferable because temperature control is easy.
  • the heating temperature after adding the solvent is higher than the boiling point of the solvent to be used. In the case of two or more mixed solvents, the heating temperature is higher than the boiling point of the lower boiling solvent and the solvent does not boil. Is preferred. If the heating temperature is too high, the required pressure increases and productivity decreases.
  • a preferable heating temperature range is 20 to 120 ° C., more preferably 30 to 100 ° C., and still more preferably 40 to 80 ° C. The pressure is adjusted so that the solvent does not boil at the set temperature.
  • additives such as necessary plasticizers and UV absorbers are mixed with the solvent in advance, dissolved or dispersed, and then added to the solvent before dissolving the cellulose ester. It may be put into the dope.
  • the peripheral speed of the stirring blade is preferably at least 0.5 m / second and stirred and dissolved for 30 minutes or more.
  • Filter media used for filtration preferably have low absolute filtration accuracy, but if the absolute filtration accuracy is too low, the filter media is likely to be clogged, and the filter media must be replaced frequently, reducing productivity. There is a problem of making it. Therefore, the filter medium used for the cellulose ester dope preferably has an absolute filtration accuracy of 0.008 mm or less, more preferably in the range of 0.001 to 0.008 mm, and further in the range of 0.003 to 0.006 mm. preferable.
  • the material of the filter medium there are no particular restrictions on the material of the filter medium, and normal filter media can be used. However, plastic fiber filter media such as polypropylene and Teflon (registered trademark), and metal filter media such as stainless steel fibers are used to remove fibers. This is preferable.
  • Filtration of the cellulose ester dope can be carried out by a usual method, but the method of filtering while heating under pressure at a temperature not lower than the boiling point at the normal pressure of the solvent and in which the solvent does not boil is a differential pressure before and after the filter medium ( Hereinafter, the increase in the filtration pressure may be small and preferable.
  • a preferable filtration temperature range is 45 to 120 ° C, more preferably 45 to 70 ° C, and further preferably 45 to 55 ° C.
  • the filtration pressure is preferably 3500 kPa or less, more preferably 3000 kPa or less, and even more preferably 2500 kPa or less.
  • the filtration pressure can be controlled by appropriately selecting the filtration flow rate and the filtration area.
  • cellulose ester is dissolved in a mixed solvent of a good solvent and a poor solvent, and the above plasticizer and ultraviolet absorber are added to the cellulose ester solution ( Dope) is prepared.
  • the dope can be cast on the support at a temperature of the support of 0 ° C. to less than the boiling point of the solvent, and further on the support at a temperature of 5 ° C. to the boiling point of the solvent ⁇ 5 ° C. Although it can be cast, it is more preferable to cast on a support in a temperature range of 5 to 30 ° C. At this time, it is necessary to control the ambient atmospheric humidity above the dew point.
  • a dope adjusted to have a dope viscosity of 1 to 200 poise is cast from the casting die onto the support so as to have a substantially uniform film thickness, and the amount of residual solvent in the casting film is solid.
  • the partial weight is 200% or more
  • the drying film temperature is lower than the boiling point of the solvent, and from the remaining solvent amount of 200% or less to peeling, the casting film temperature is in the range of the boiling point of the solvent + 20 ° C. or less.
  • M is the weight of the web at an arbitrary time point
  • N is the weight when a weight M is dried at 110 ° C. for 3 hours.
  • the residual solvent in the web in order to dry and solidify the web until the film has a peelable film strength, it is preferable to dry the residual solvent in the web to 150% by mass or less, and more preferably 50 to 120%.
  • the web temperature when peeling the web from the support is preferably 0-30 ° C.
  • the temperature immediately after the web is peeled off from the support, the temperature once drops rapidly due to solvent evaporation from the support close-contact surface side, and volatile components such as water vapor and solvent vapor in the atmosphere tend to condense.
  • the web temperature is more preferably 5 to 30 ° C. *
  • a method of drying while conveying the web by a roll suspension method, a pin tenter method or a clip tenter method is adopted.
  • the web after peeling is introduced into, for example, a primary drying apparatus.
  • the web is meandered and conveyed by a plurality of conveying rolls arranged in a staggered manner as viewed from the side, while the web is blown from the ceiling of the drying device and discharged from the bottom portion of the drying device. Dried by wind.
  • the obtained film (sheet) is stretched in a uniaxial direction.
  • the molecules are oriented by stretching.
  • the stretching method is not particularly limited, but a known pin tenter or clip type tenter can be preferably used.
  • the stretching direction can be a length direction, a width direction, or an arbitrary direction (an oblique direction). However, by setting the stretching direction to the width direction, the elongation at break of the original film can be easily adjusted, which is preferable.
  • the web tends to shrink in the width direction due to evaporation of the solvent. Shrinkage increases with drying at higher temperatures. Drying while suppressing this shrinkage as much as possible is preferable for improving the flatness of the finished film. From this point, for example, a method of drying the whole drying process or a part of the process as shown in Japanese Patent Application Laid-Open No. 62-46625 while holding the width at both ends of the web with a clip in the width direction (tenter method) ) Is preferred.
  • the temperature and the magnification can be selected so that desired breaking elongation characteristics can be obtained.
  • the stretching ratio is 1.1 to 2.0 times, preferably 1.2 to 1.5 times
  • the stretching temperature is usually the glass transition temperature (Tg) of the resin constituting the sheet ⁇ 40 ° C. to Tg + 50. It is set in the temperature range of ° C, preferably Tg-40 ° C to Tg + 40 ° C. If the draw ratio is too small, the desired elongation at break property may not be obtained. Conversely, if the draw ratio is too large, it may break. If the stretching temperature is too low, it will break, and if it is too high, the desired elongation at break property may not be obtained.
  • the film may be stretched or shrunk in the length direction or the width direction.
  • a method of shrinking the film by temporarily clipping out the width stretching and relaxing in the length direction, or by gradually narrowing the interval between adjacent clips of the transverse stretching apparatus.
  • the latter method can be performed by using a general simultaneous biaxial stretching apparatus, and by gradually and gradually narrowing the interval between adjacent clips in the longitudinal direction by driving the clip portion by, for example, a pantograph method or a linear drive method. it can.
  • Gripping and stretching with a tenter can be performed anywhere from 50 to 150% by mass of the residual solvent of the film immediately after peeling to 0% by mass of the residual residual solvent immediately before winding. Is preferably in the range of 5 to 10%.
  • the temperature in the drying zone before and after the tenter is also selected from a temperature different from the temperature during stretching for various reasons.
  • the temperature in the zone near the tenter inlet is set to an intermediate temperature between the temperature in the drying zone before the tenter and the temperature in the center of the tenter. It is generally done.
  • the temperature in the zone near the tenter outlet is set to an intermediate temperature between the temperature after the tenter and the temperature in the tenter.
  • the temperature of the drying zone before and after the tenter is generally 30 to 120 ° C., preferably 50 to 100 ° C., and the temperature of the stretching portion in the tenter is 50 to 180 ° C., preferably 80 to 170 ° C.
  • the temperature is appropriately selected from intermediate temperatures thereof.
  • the pattern of stretching i.e. the trajectory of the grip clip, is selected from the optical properties and flatness of the film as well as the temperature, and varies, but for a while after the start of gripping, it is stretched for a while, then stretched and then stretched again at a constant width. A retained pattern is often used. In the vicinity of the end of gripping near the tenter outlet, width relaxation is generally performed to suppress base vibration by releasing the gripping.
  • the stretching pattern is also related to the stretching speed, but the stretching speed is generally 10 to 1000 (% / min), preferably 100 to 500 (% / min). This stretching speed is not constant when the clip trajectory is a curve, and gradually changes in the base traveling direction.
  • the web (film) after drying by the tenter method is then introduced into a secondary drying apparatus.
  • the web is meandered and conveyed by a plurality of conveying rolls arranged in a staggered manner as viewed from the side, while the web is blown from the ceiling of the secondary drying apparatus, and the bottom part of the secondary drying apparatus It is dried by the warm air discharged more and wound on a winder as a raw film of cellulose ester resin.
  • the means for drying the web is not particularly limited, and hot air, infrared rays, heating rolls, microwaves and the like are generally used. In terms of simplicity, it is preferable to dry with hot air.
  • the drying temperature is preferably 40 to 150 ° C., more preferably 80 to 130 ° C. in order to improve the flatness and dimensional stability.
  • the web peeled from the support is further dried, and finally the residual solvent amount is 3% by mass or less, preferably 1% by mass or less, more preferably 0.5% by mass.
  • the residual solvent amount is 3% by mass or less, preferably 1% by mass or less, more preferably 0.5% by mass. The following is preferable in obtaining a film having good dimensional stability.
  • These steps from casting to post-drying may be performed in an air atmosphere or an inert gas atmosphere such as nitrogen gas.
  • an inert gas atmosphere such as nitrogen gas.
  • the embossing is formed on both side edges of the cellulose ester resin raw film by an embossing device before the introduction to the winding process with respect to the cellulose ester resin raw film after the transport drying process. It is preferable to perform processing.
  • an embossing apparatus for example, an apparatus described in JP-A-63-74850 can be used.
  • Winders related to the production of cellulose ester resin film can be generally used, such as constant tension method, constant torque method, taper tension method, program tension control method with constant internal stress, etc. It can be wound up by a winding method.
  • the film thickness of the original film after winding varies depending on the purpose of use, but the film thickness range is 20 to 200 ⁇ m. For the recent thinness trend, the range of 30 to 120 ⁇ m is preferable, and the range of 40 to 100 ⁇ m is particularly preferable.
  • the raw film of the present embodiment is produced by a melt casting film forming method
  • an ultraviolet absorber that can be used
  • those used in the method for producing an original film by the solution casting film forming method Almost the same one can be used.
  • the blending amount of these ultraviolet absorbers is preferably in the range of 0.01 to 10% by mass, more preferably 0.1 to 5% by mass with respect to the thermoplastic resin. If the amount used is too small, the UV absorption effect may be insufficient, and conversely if too large, the transparency of the film may deteriorate.
  • the ultraviolet absorber is preferably one having high heat stability.
  • the fine particles used may be either an inorganic compound or an organic compound as long as it has heat resistance during melting.
  • the inorganic compound includes a compound containing silicon, silicon dioxide, aluminum oxide, zirconium oxide, calcium carbonate, talc, clay.
  • silicon dioxide is particularly preferably used because haze can be kept small.
  • the matting agent used is substantially the same as that used in the method for producing an original film by the solution casting film forming method. be able to.
  • Examples of the melt casting film forming method include a method using a T die, a melt extrusion method such as an inflation method, a calendar method, a hot press method, and an injection molding method.
  • a method using a T-die that has a small thickness unevenness, can be easily processed to a thickness of about 50 to 500 ⁇ m, and can reduce the film thickness unevenness and retardation unevenness is preferable.
  • the extrusion method using a T die is a method in which a polymer is melted at a temperature at which it can be melted, extruded onto a cooling drum from a T die on a cooling drum, solidified by cooling, and peeled off from the cooling drum.
  • the thickness accuracy of the film is excellent and can be preferably used.
  • Melt extrusion can be performed under the same conditions as those used for other thermoplastic resins such as polyester.
  • cellulose ester dried under hot air, vacuum or reduced pressure is melted at an extrusion temperature of about 200-300 ° C using a single-screw or twin-screw extruder, and then filtered through a leaf disk filter to remove foreign matter. Then, the film is cast from the T die into a film (sheet) and solidified on a cooling drum.
  • the extrusion flow rate is preferably performed stably by introducing a gear pump or the like.
  • a stainless fiber sintered filter is preferably used as a filter used for removal of a foreign material.
  • a stainless steel fiber sintered filter is an integrated stainless steel fiber body that is intricately entangled and then compressed and sintered at the contact point. The density is changed according to the thickness of the fiber and the amount of compression, and the filtration accuracy is improved. Can be adjusted. It is preferable to use a multilayer body in which the filtration accuracy is repeated coarsely and densely a plurality of times. In addition, it is preferable to adopt a configuration in which the filtration accuracy is sequentially increased or a method in which coarse and dense filtration accuracy is repeated, so that the filtration life of the filter is extended and the accuracy of supplementing foreign matters and gels can be improved.
  • the piping from the extruder to the die has a structure in which the resin retention portion is minimized. . Further, it is preferable to use a die that has as few scratches as possible in the lip or lip. Since the volatile component may be deposited from the resin around the die and cause a die line, it is preferable to suck the atmosphere containing the volatile component. Moreover, since it may precipitate also in apparatuses, such as an electrostatic application, it is preferable to apply alternating current or to prevent precipitation with another heating means.
  • Additives such as plasticizers may be mixed with the resin in advance, or may be kneaded in the middle of the extruder. In order to add uniformly, it is preferable to use a mixing apparatus such as a static mixer.
  • the temperature of the cooling drum is preferably below the glass transition temperature of the thermoplastic resin.
  • the thermoplastic resin original film formed by such a melt casting film forming method has a feature that the thickness direction retardation (Rt) is small.
  • stretching conditions different from the solution casting film-forming method may be required.
  • both stretching in the film traveling direction and stretching in the film width direction may be performed simultaneously or sequentially.
  • it may be only extending
  • the thickness of the raw film in this embodiment is 1 to 400 ⁇ m, preferably 20 to 200 ⁇ m, more preferably 30 to 120 ⁇ m, and particularly preferably in the range of 40 to 100 ⁇ m.
  • the thickness unevenness ⁇ m in the flow direction (conveying direction) of the original film supplied to the stretching zone which will be described later, maintains the film take-up tension at the oblique stretching tenter inlet, which will be described later, and the orientation angle. From the viewpoint of stabilizing optical properties such as retardation and retardation, it is necessary to be less than 0.30 ⁇ m, preferably less than 0.25 ⁇ m, and more preferably less than 0.20 ⁇ m. When the thickness unevenness ⁇ m in the flow direction of the original film is 0.30 ⁇ m or more, variations in optical properties such as retardation and orientation angle of the long obliquely stretched film are remarkably deteriorated.
  • the thickness unevenness in the width direction of the original film is small.
  • the difference in thickness between the thick-side end and the thin-side end is less than about 2.0% of the thickness, preferably less than about 1.0%. It is desirable that the range be less than 0.5%.
  • the width of the raw film is not particularly limited, but can be 500 to 4000 mm, preferably 1000 to 2000 mm.
  • the preferable elastic modulus at the stretching temperature at the time of oblique stretching of the raw film is 0.01 MPa or more and 5000 MPa or less, more preferably 0.1 MPa or more and 500 MPa or less, expressed as Young's modulus. If the elastic modulus is too low, the shrinkage rate during and after stretching becomes low and wrinkles are difficult to disappear. On the other hand, if the elastic modulus is too high, the tension applied during stretching increases, and it is necessary to increase the strength of the portions that hold the side edges of the film, which increases the load on the tenter in the subsequent step.
  • a non-oriented film may be used, or a film having an orientation in advance may be supplied. Further, if necessary, the distribution in the width direction of the orientation of the raw film may be bow-shaped, so-called bowing. In short, the orientation state of the raw film can be adjusted so that the orientation of the film at the position where the stretching in the subsequent step is completed can be made desirable.
  • FIG. 1 is a plan view schematically showing a schematic configuration of a manufacturing apparatus 1 for an obliquely stretched film.
  • the manufacturing apparatus 1 includes, in order from the upstream side in the transport direction of the long film, a film feeding unit 2, a transport direction changing unit 3, a guide roll 4, a stretching unit 5, a guide roll 6, and a transport direction changing unit 7.
  • the film winding unit 8 is provided.
  • a film cutting device is provided between the conveyance direction changing unit 7 and the film winding unit 8 so that the film after oblique stretching is cut at a desired length and wound by the film winding unit 8. Also good.
  • the details of the extending portion 5 will be described later.
  • the film feeding unit 2 feeds the above-described long film and supplies it to the stretching unit 5.
  • This film supply part 2 may be comprised separately from the film-forming apparatus of a long film, and may be comprised integrally.
  • a long film is wound around a core after film formation, and a wound body (long film original fabric) is loaded into the film unwinding section 2 so that the film unwinds from the film unwinding section 2. The film is paid out.
  • the film feeding unit 2 feeds the long film to the stretching unit 5 without winding the long film after the long film is formed.
  • the conveyance direction changing unit 3 changes the conveyance direction of the long film fed from the film feeding unit 2 to a direction toward the entrance of the stretching unit 5 as an oblique stretching tenter.
  • a conveyance direction change part 3 is comprised including the turntable which rotates the turn bar which changes the conveyance direction by, for example, returning while conveying a film, and the turn bar in the surface parallel to a film.
  • the width of the entire manufacturing apparatus 1 can be made narrower, and the film feed position and angle are finely controlled. Accordingly, it is possible to obtain a diagonally stretched film with small variations in film thickness and optical value. Further, if the film feeding unit 2 and the conveyance direction changing unit 3 can be moved (slidable and turnable), the left and right clips (gripping tools) sandwiching both ends of the long film in the width direction in the stretching unit 5 can be used. It is possible to effectively prevent the biting into the film.
  • the above-described film feeding unit 2 may be slidable and turnable so that a long film can be fed out at a predetermined angle with respect to the entrance of the stretching unit 5.
  • a configuration in which the installation of the conveyance direction changing unit 3 is omitted may be employed.
  • At least one guide roll 4 is provided on the upstream side of the stretching portion 5 in order to stabilize the track during running of the long film.
  • the guide roll 4 may be comprised by a pair of upper and lower rolls which pinch
  • the guide roll 4 closest to the entrance of the extending portion 5 is a driven roll that guides the travel of the film, and is rotatably supported via a bearing portion (not shown).
  • a known material can be used as the material of the guide roll 4.
  • one of the rolls upstream of the guide roll 4 closest to the entrance of the extending portion 5 is nipped by pressing the rubber roll.
  • a pair of bearing portions at both ends (left and right) of the guide roll 4 closest to the entrance of the extending portion 5 includes a first tension detecting device as a film tension detecting device for detecting the tension generated in the film in the roll,
  • a second tension detecting device is provided.
  • a load cell can be used as the film tension detection device.
  • the load cell a known tensile or compression type can be used.
  • a load cell is a device that detects a load acting on an applied point by converting it into an electrical signal using a strain gauge attached to the strain generating body.
  • the load cell is installed in the left and right bearing portions of the guide roll 4 closest to the entrance of the extending portion 5, whereby the force of the running film on the roll, that is, in the film traveling direction generated in the vicinity of both side edges of the film.
  • the tension is detected independently on the left and right.
  • a strain gauge may be directly attached to a support that constitutes the bearing portion of the roll, and a load, that is, a film tension may be detected based on the strain generated in the support. The relationship between the generated strain and the film tension is measured in advance and is known.
  • the position and the transport direction of the film are changed by, for example, the transport direction changing unit 3 so that the difference in film tension between the left and right sides of the guide roll 4 closest to the entrance of the stretching unit 5 becomes equal.
  • the film can be stably held by the gripping tool at the entrance of the stretching portion 5, and the occurrence of obstacles such as detachment of the gripping tool can be reduced.
  • the physical properties in the width direction of the film after oblique stretching by the stretching portion 5 can be stabilized.
  • At least one guide roll 6 is provided on the downstream side of the stretching portion 5 in order to stabilize the track during running of the film that is obliquely stretched in the stretching portion 5.
  • the transport direction changing unit 7 changes the transport direction of the stretched film transported from the stretching unit 5 to a direction toward the film winding unit 8.
  • the film traveling direction at the entrance of the stretching portion 5 and the film traveling direction at the exit of the stretching portion 5 It is necessary to adjust the angle between the two.
  • the traveling direction of the formed film is changed by the transport direction changing unit 3 to guide the film to the inlet of the stretching unit 5 and / or the traveling direction of the film from the outlet of the stretching unit 5 Needs to be changed by the transport direction changing unit 7 to return the film to the direction of the film winding unit 8.
  • the film formation and oblique stretching are continuously performed.
  • the traveling direction of the film is changed by the transport direction changing unit 3 and / or the transport direction changing unit 7, and the film is formed by the film forming process and the winding process. 1, that is, as shown in FIG. 1, the traveling direction (feeding direction) of the film fed from the film feeding unit 2 and the traveling direction of the film immediately before being wound by the film winding unit 8 ( The width of the entire apparatus with respect to the film traveling direction can be reduced by matching the winding direction.
  • the film traveling direction and the film winding process do not necessarily coincide with each other in the film forming process and the film winding process. It is preferable that the traveling direction of the film is changed by the transport direction changing unit 7.
  • the transport direction changing units 3 and 7 as described above can be realized by a known method such as using an air flow roll or an air turn bar.
  • the film take-up unit 8 takes up a film conveyed from the stretching unit 5 via the conveyance direction changing unit 7, and includes, for example, a winder device, an accumulator device, and a drive device. It is preferable that the film winding unit 8 has a structure that can be slid in the horizontal direction in order to adjust the film winding position.
  • the film take-up unit 8 can finely control the film take-up position and angle so that the film can be taken at a predetermined angle with respect to the outlet of the stretching unit 5. Thereby, it becomes possible to obtain a long obliquely stretched film with small variations in film thickness and optical value. In addition, it is possible to effectively prevent wrinkling of the film and to improve the winding property of the film, so that the film can be wound up in a long length.
  • the film take-up unit 8 constitutes a take-up unit that takes up the film that is drawn and conveyed by the drawing unit 5 with a certain tension. Note that a take-up roll for taking up the film with a constant tension may be provided between the stretching unit 5 and the film take-up unit 8. Moreover, you may give the function as said take-up roll to the guide roll 6 mentioned above.
  • the take-up tension T (N / m) of the stretched film is preferably adjusted between 100 N / m ⁇ T ⁇ 300 N / m, preferably 150 N / m ⁇ T ⁇ 250 N / m.
  • the take-up tension is 100 N / m or less, sagging and wrinkles of the film are likely to occur, and the retardation and orientation angle profile in the film width direction are also deteriorated.
  • the take-up tension is 300 N / m or more, the variation of the orientation angle in the film width direction is deteriorated, and the width yield (taken efficiency in the width direction) is deteriorated.
  • the fluctuation of the take-up tension T it is preferable to control the fluctuation of the take-up tension T with an accuracy of less than ⁇ 5%, preferably less than ⁇ 3%.
  • the variation in the take-up tension T is ⁇ 5% or more, the variation in the optical characteristics in the width direction and the flow direction (conveying direction) increases.
  • the load applied to the first roll (guide roll 6) on the outlet side of the stretching section 5, that is, the film tension is measured, and the value becomes constant.
  • the method of controlling the rotational speed of the take-up roll or the take-up roll of the film take-up part 8 by a general PID control system is mentioned.
  • Examples of the method for measuring the load include a method in which a load cell is attached to the bearing portion of the guide roll 6 and a load applied to the guide roll 6, that is, a film tension is measured.
  • a load cell a known tensile type or compression type can be used.
  • the stretched film is released from the outlet of the stretching unit 5 by being held by the gripping tool of the stretching unit 5 and trimmed at both ends (both sides) of the film that has been gripped by the gripping tool. It is wound up by (winding roll), and becomes a wound body of a long diagonally stretched film. Note that the above trimming may be performed as necessary.
  • a masking film may be piled up on a long diagonally stretched film, and it may wind up simultaneously, and the long diagonal stretch which overlaps by winding up You may wind up, sticking a tape etc. to the edge of at least one (preferably both) of a film.
  • the masking film is not particularly limited as long as it can protect the long obliquely stretched film, and examples thereof include a polyethylene terephthalate film, a polyethylene film, and a polypropylene film.
  • At least one side (preferably both sides) of the film is bulkier than the film side, which is called a knurling part or an embossed part, at both ends in the width direction. You may make it prevent blocking of films when a film is wound up by forming the part (convex part) which did.
  • the height and shape of the knurling portion may be different at both ends in the width direction (may be asymmetric).
  • FIG. 2 is a plan view schematically showing an example of the rail pattern of the extending portion 5.
  • this is an example, and the configuration of the extending portion 5 is not limited to this.
  • the production of the long obliquely stretched film in the present embodiment is performed by using a tenter (obliquely stretching machine) capable of oblique stretching as the stretching part 5.
  • This tenter is an apparatus that heats a long film to an arbitrary temperature at which it can be stretched and obliquely stretches it.
  • This tenter includes a heating zone Z, a pair of rails Ri and Ro on the left and right, and a number of gripping tools Ci and Co that travel along the rails Ri and Ro to convey a film (in FIG. 2, a set of gripping tools). Only). Details of the heating zone Z will be described later.
  • Each of the rails Ri and Ro is configured by connecting a plurality of rail portions with connecting portions (white circles in FIG. 2 are examples of connecting portions).
  • the gripping tool Ci / Co is composed of a clip that grips both ends of the film in the width direction.
  • the feeding direction D1 of the long film is different from the winding direction D2 of the stretched long diagonally stretched film, and forms a feeding angle ⁇ i with the winding direction D2.
  • the feeding angle ⁇ i can be arbitrarily set to a desired angle in the range of more than 0 ° and less than 90 °.
  • the rail pattern of the tenter has an asymmetric shape on the left and right, and the film transport path is bent halfway. And a rail pattern can be adjusted now manually or automatically according to the orientation angle
  • corner (theta) given to the long diagonally stretched film which should be manufactured, a draw ratio, etc.
  • FIG. In the oblique stretching machine used in the manufacturing method of the present embodiment, it is preferable that the positions of the rail portions and the rail connecting portions constituting the rails Ri and Ro can be freely set and the rail pattern can be arbitrarily changed.
  • the tenter gripping tool Ci ⁇ Co travels at a constant speed with a constant interval from the front and rear gripping tools Ci ⁇ Co.
  • the traveling speed of the gripping tool Ci / Co can be selected as appropriate, but is usually 1 to 150 m / min. In the present embodiment, it is preferably 20 to 100 m / min in consideration of the temperature change by reliably heating the film in the width direction as described later and the productivity of the film.
  • the difference in travel speed between the pair of left and right grippers Ci / Co is usually 1% or less, preferably 0.5% or less, more preferably 0.1% or less of the travel speed.
  • a high bending rate is often required for the rail that regulates the trajectory of the gripping tool, particularly at a location where the film is transported obliquely.
  • the obliquely stretched tenter used for imparting the oblique orientation to the long film can freely set the orientation angle of the film by changing the rail pattern in various ways, and further, the orientation axis of the film It is preferred that the tenter be capable of orienting the (slow axis) in the left and right direction with high precision across the film width direction and controlling the film thickness and retardation with high precision.
  • Both ends of the long film are gripped by the left and right grippers Ci ⁇ Co, and are conveyed in the heating zone Z as the grippers Ci • Co travel.
  • the left and right grips Ci / Co are opposed to a direction substantially perpendicular to the film traveling direction (feeding direction D1) at the entrance portion (position A in the drawing) of the extending portion 5, and are asymmetric rails.
  • Each travels on Ri and Ro, and the film gripped at the exit portion (position B in the figure) at the end of stretching is released.
  • the film released from the gripping tool Ci ⁇ Co is wound around the core by the film winding portion 8 described above.
  • Each of the pair of rails Ri and Ro has an endless continuous track, and the grippers Ci and Co that have released the film at the exit portion of the tenter travel on the outer rail and sequentially return to the entrance portion. It is supposed to be.
  • the left and right gripping tools Ci and Co which are opposed to each other at the position A in the figure, move along the rails Ri and Ro.
  • the gripping tool Ci traveling on the Ri side (in-course side) has a positional relationship preceding the gripping tool Co traveling on the rail Ro side (out-course side).
  • one gripping tool Ci is first in position B at the end of film stretching.
  • the straight line connecting the gripping tools Ci and Co is inclined by an angle ⁇ L with respect to the direction substantially perpendicular to the film winding direction D2.
  • the long film is obliquely stretched at an angle of ⁇ L with respect to the width direction.
  • substantially vertical indicates that the angle is in a range of 90 ⁇ 1 °.
  • the heating zone Z of the stretching section 5 is composed of a preheating zone Z1, a stretching zone Z2, and a heat fixing zone Z3.
  • the film gripped by the gripping tool Ci / Co passes through the preheating zone Z1, the stretching zone Z2, and the heat fixing zone Z3 in this order.
  • the preheating zone Z1 and the stretching zone Z2 are separated by a partition, and the stretching zone Z2 and the heat fixing zone Z3 are separated by a partition.
  • the preheating zone Z1 refers to a section in which the gripping tool Ci / Co that grips both ends of the film travels at the left and right (in the film width direction) at a constant interval at the entrance of the heating zone Z.
  • the stretching zone Z2 refers to a section from when the gap between the gripping tools Ci and Co that grips both ends of the film opens until a predetermined gap is reached. At this time, the oblique stretching as described above is performed, but the stretching may be performed in the longitudinal direction or the transverse direction before and after the oblique stretching as necessary. That is, in the stretching zone Z2, while gripping both ends in the width direction of the film with a pair of gripping tools Ci and Co, one gripping tool Ci is relatively advanced and the other gripping tool Co is relatively delayed. Then, the film is transported, and the film transport path is bent halfway, thereby performing an oblique stretching process of stretching the film in an oblique direction with respect to the width direction.
  • the heat fixing zone Z3 refers to a section for fixing the optical axis (slow axis) of the obliquely stretched film after the oblique stretching process in the stretching zone Z2. That is, in the heat setting zone Z3, a heat setting process for fixing the optical axis of the obliquely stretched film is performed. In the heat setting zone Z3, the gripping tools Ci and Co at both ends travel while being kept parallel to each other. Thereby, the optical axis of the obliquely stretched film is fixed.
  • the stretched film passes through the heat setting zone Z3 and then passes through a section (cooling zone) in which the temperature in the zone is set to be equal to or lower than the glass transition temperature Tg (° C.) of the thermoplastic resin constituting the film. May be.
  • the temperature of the preheating zone Z1 is Tg to Tg + 60 ° C.
  • the temperature of the stretching zone Z2 is Tg to Tg + 50 ° C.
  • the temperature of the heat setting zone Z3 and the cooling zone is Tg ⁇ 40 to Tg + 30 ° C. with respect to the glass transition temperature Tg of the thermoplastic resin. It is preferable to set.
  • the lengths of the preheating zone Z1, the stretching zone Z2, and the heat setting zone Z3 can be appropriately selected.
  • the length of the preheating zone Z1 is usually 50 to 200% of the length of the stretching zone Z2, and the length of the heat setting zone Z3.
  • the length is usually 50 to 150%.
  • the draw ratio R (W / Wo) in the stretching step is preferably 1.1-3. 0, more preferably 1.15 to 2.0.
  • the draw ratio is in this range, the thickness unevenness in the width direction of the film is preferably reduced.
  • the method of oblique stretching in the stretching portion 5 is not limited to the above-described method.
  • the oblique stretching may be performed by simultaneous biaxial stretching as disclosed in JP-A-2008-23775. Good.
  • simultaneous biaxial stretching means that both ends in the width direction of the supplied long film are gripped by each gripping tool, and the long film is transported while moving each gripping tool, and the long film is transported.
  • This is a method of stretching a long film in an oblique direction with respect to the width direction by making the moving speed of one gripping tool different from the moving speed of the other gripping tool while keeping the direction constant.
  • oblique stretching may be performed by a technique disclosed in Japanese Patent Application Laid-Open No. 2011-11434.
  • FIG. 3 schematically shows the shape of the film passing through the stretched portion 5 of FIG.
  • the width of the obliquely stretched film before widening after the end of the oblique stretching in the stretching zone Z2 is L1
  • the width L1 of the obliquely stretched film before widening in the heat setting zone Z3 heat setting step.
  • L2 and L3 be the widths of the portions widened to the leading side and the delay side relative to the portion corresponding to.
  • the preceding side refers to the gripping tool Ci side that travels relatively ahead of the pair of gripping tools Ci and Co that grips both ends of the film, and the delay side relatively delays. It points to the gripping tool Co side that runs.
  • the units of L1, L2, and L3 are all mm.
  • the obliquely stretched film is widened so as to satisfy the following conditional expression (1). That is, L3> L2 ⁇ 0 mm (1) It is.
  • FIG. 4 schematically shows how the avalan-like residual stress is relaxed when the obliquely stretched film is widened in the heat setting zone Z3.
  • the film stretched obliquely in the stretching zone Z2 enters the heat setting zone Z3, but at this time, since the leading side enters the heat setting zone Z3 earlier than the delay side, the shrinkage of the film starts from the leading side, Abalone residual stress T is generated up to the vicinity of the center in the width direction. However, since the film extends in the width direction by widening the film in the heat setting zone Z3, the loose residual stress generated in the heat setting zone Z3 is relaxed and does not remain in the film.
  • the circularly-polarizing plate mentioned later is comprised using the manufactured diagonally stretched film, even if this circularly-polarizing plate is applied to OLED (organic EL image display apparatus), and OLED is put in the temperature / humidity environment different from usual. Thus, it is possible to suppress the appearance of oblique stripe-shaped display unevenness.
  • the optical axis (slow axis) oriented in a predetermined direction by oblique stretching by satisfying the conditional expression (1), that is, by increasing the width of the film on the delay side rather than the preceding side, It is possible to suppress the occurrence of an avalan-like residual stress without causing any deviation from the predetermined direction.
  • the film when widening the obliquely stretched film, if the leading side is too wide, the film is pulled in the direction in which the leading side is widened (the direction toward the lower right in FIG. 4), so that the direction of the optical axis of the film is shifted.
  • the orientation angle of the film oriented in the direction of 45 ° with respect to the width direction is too wide on the leading side, it becomes as small as 44 °.
  • the delay side of the film originally tends to have a small orientation angle (due to the bowing phenomenon), and the direction in which the delay side is widened (the direction toward the upper left in FIG. 4) is the orientation angle on the delay side (for example, Since it is a direction to increase the angle (from 44 ° to 45 °), there is no problem even if the delay side is wider than the preceding side, and it is preferable because the orientation direction approaches a predetermined direction.
  • conditional expression (1) it is possible to prevent the optical axis from deviating from a predetermined direction (for example, a direction of 45 ° with respect to the width direction) on the leading side and the delay side of the film. .
  • a predetermined direction for example, a direction of 45 ° with respect to the width direction
  • an obliquely stretched film having desired orientation characteristics can be obtained by fixing the optical axis in a predetermined direction.
  • the ratio B is 5% or more
  • the widening width on the delay side becomes too large, and the optical property value adjusted in the stretching zone changes due to the heat setting zone stretching, and the uniformity deteriorates.
  • 5%> B it is possible to achieve both avalan residual stress and uniformity.
  • B> A ⁇ 0% at least the delay side of the film is widened more than the preceding side, and it is possible to suppress the occurrence of loose residual stress in the film after oblique stretching.
  • the optical axis provided by the oblique stretching in the oblique stretching step can be reliably fixed. Therefore, in the heat setting step, it is desirable to widen the obliquely stretched film at a temperature that is 10 ° C. to 60 ° C. lower than the stretching temperature in the oblique stretching step, and more preferably a temperature that is 20 ° C. to 50 ° C. lower.
  • the ratio B when the ratio B is less than 1%, the widening width on the delay side is small, and the effect due to the widening of the film, that is, the effect of suppressing the occurrence of avalan residual stress is small.
  • the ratio B if the ratio B is larger than 4%, the effect of stretching in the heat setting zone becomes strong, and the level of uniformity decreases. Therefore, it is desirable that 4% ⁇ B ⁇ 1% from the viewpoint of avoiding a decrease in the level of uniformity while ensuring the effect of widening the film.
  • the orientation angle is likely to fluctuate due to moisture absorption.
  • the film delay side is broadened more than the preceding side, thereby suppressing the occurrence of avalan residual stress while suppressing the fluctuation of the orientation angle. This is very effective when the stretched film contains a cellulose ester resin.
  • the orientation angle ⁇ is inclined in the range of, for example, greater than 0 ° and less than 90 ° with respect to the winding direction, and at least at a width of 1300 mm.
  • the variation in the in-plane retardation Ro in the width direction is preferably 2 nm or less, and the variation in the orientation angle ⁇ is preferably less than 0.6 °.
  • the in-plane retardation value Ro (550) measured at a wavelength of 550 nm of the long obliquely stretched film is preferably in the range of 80 nm to 160 nm, and more preferably in the range of 90 nm to 150 nm.
  • the variation of the in-plane retardation Ro is 2 nm or less and preferably 1 nm or less at least 1300 mm in the width direction.
  • the variation in the orientation angle ⁇ is less than 0.6 ° and less than 0.4 ° or less at least 1300 mm in the width direction. Is preferable, and less than 0.2 ° is most preferable.
  • a long diagonally stretched film with a variation in the orientation angle ⁇ exceeding 0.6 ° is bonded to a polarizer to form a circularly polarizing plate, and this is installed in an image display device such as an organic EL display device, light leakage occurs, and light and dark May reduce the contrast.
  • the average thickness of the long obliquely stretched film obtained by the production method of the present embodiment is 1 to 400 ⁇ m, preferably 10 to 200 ⁇ m, more preferably 10 to 60 ⁇ m, and particularly preferably 15 to from the viewpoint of mechanical strength. 45 ⁇ m.
  • the thickness unevenness in the width direction of the long obliquely stretched film affects whether or not winding is possible, it is preferably 2 ⁇ m or less, and more preferably 1 ⁇ m or less.
  • the long diagonally stretched film obtained by the production method of the present embodiment may have a functional layer on the surface.
  • Functional layers include antireflection layer, low refractive index layer, hard coat layer, light scattering layer, light diffusion layer, antistatic layer, conductive layer, electrode layer, birefringence layer, surface energy adjustment layer, UV absorption layer, color
  • a material layer, a water resistant layer, a specific gas barrier layer, a heat resistant layer, a magnetic layer, an antioxidant layer, an overcoat layer and the like can be considered.
  • a polarizing plate protective film, a polarizer, and a ⁇ / 4 film are laminated in this order, and the slow axis of the ⁇ / 4 film and the absorption axis (or transmission axis) of the polarizer Is an angle of 45 °.
  • the above polarizing plate protective film, polarizer, and ⁇ / 4 film are the same as the protective film 313, polarizer 311, and ⁇ / 4 film 316 in FIG. Each corresponds.
  • it is preferable that a long polarizing plate protective film, a long polarizer, and a long ⁇ / 4 film (long diagonally stretched film) are laminated in this order.
  • the above polarizing plate protective film, polarizer, and ⁇ / 4 film are the protective film 506, polarizer 501, and ⁇ / 4 film 503 in FIG. Correspond to each. Since the protective film 506 and the polarizer 501 are disposed outside the display cell 401 (viewing side), and the ⁇ / 4 film 503 is disposed further outside (on the viewing side) of the polarizer 501, display is performed. The linearly polarized light emitted from the cell 401 and transmitted through the polarizer 501 is converted into circularly polarized light or elliptically polarized light by the ⁇ / 4 film 503.
  • the observation angle is whatever (at the transmission axis of the polarizer 501 (perpendicular to the absorption axis)) the polarization sunglasses. Even if the transmission axis is misaligned), the display image can be observed by guiding the light component parallel to the transmission axis of the polarized sunglasses to the observer's eyes, and the display image is difficult to see depending on the viewing angle. It can be suppressed.
  • the circularly polarizing plate of the present embodiment can be manufactured by using a stretched polyvinyl alcohol doped with iodine or a dichroic dye as a polarizer, and laminating with a configuration of ⁇ / 4 film / polarizer. it can.
  • the thickness of the polarizer is 5 to 40 ⁇ m, preferably 5 to 30 ⁇ m, particularly preferably 5 to 20 ⁇ m.
  • the polarizing plate can be produced by a general method.
  • the ⁇ / 4 film subjected to the alkali saponification treatment is preferably bonded to one surface of a polarizer produced by immersing and stretching a polyvinyl alcohol film in an iodine solution using a completely saponified polyvinyl alcohol aqueous solution.
  • the polarizing plate can be constituted by further bonding a release film on the opposite surface of the polarizing plate protective film of the polarizing plate.
  • the protective film and the release film are used for the purpose of protecting the polarizing plate at the time of shipping the polarizing plate, product inspection, and the like.
  • FIG. 5 is a cross-sectional view showing a schematic configuration of the organic EL display device 100 as the OLED of the present embodiment.
  • the configuration of the organic EL display device 100 is not limited to this.
  • the organic EL display device 100 is configured by forming a circularly polarizing plate 301 on an organic EL element 101 through an adhesive layer 201.
  • the organic EL element 101 includes a metal electrode 112, a light emitting layer 113, a transparent electrode (ITO, etc.) 114, and a sealing layer 115 on a substrate 111 made of glass, polyimide, or the like.
  • the metal electrode 112 may be composed of a reflective electrode and a transparent electrode.
  • the circularly polarizing plate 301 is formed by laminating a ⁇ / 4 film 316, an adhesive layer 315, a polarizer 311, an adhesive layer 312, a protective film 313, and a cured layer 314 in order from the organic EL element 101 side. / 4 film 316 and protective film 313. By pasting both together so that the angle formed by the transmission axis of the polarizer 311 and the slow axis of the ⁇ / 4 film 316 made of the long obliquely stretched film of this embodiment is about 45 ° (or 135 °).
  • a circularly polarizing plate 301 is configured.
  • a cured layer 314 is laminated on the protective film 313.
  • the hardened layer 314 not only prevents scratches on the surface of the organic EL display device 100 but also has an effect of preventing warpage due to the circularly polarizing plate 301.
  • an antireflection layer may be formed on the hardened layer 314.
  • the thickness of the organic EL element 101 itself is about 1 ⁇ m.
  • the light emitting layer is a laminate of various organic thin films, for example, a laminate of a hole injection layer made of a triphenylamine derivative and the like and a light emitting layer made of a fluorescent organic solid such as anthracene, Structures having various combinations such as a laminate of such a light emitting layer and an electron injection layer made of a perylene derivative, a hole injection layer, a light emitting layer, and a laminate of an electron injection layer are known.
  • holes and electrons are injected into the light-emitting layer by applying a voltage to the transparent electrode and the metal electrode, and the energy generated by recombination of these holes and electrons excites the fluorescent material. It emits light on the principle that it emits light when the excited fluorescent material returns to the ground state.
  • the mechanism of recombination on the way is the same as that of a general diode, and as can be expected from this, the current and the light emission intensity show strong nonlinearity with rectification with respect to the applied voltage.
  • an organic EL display device in order to extract light emitted from the light emitting layer, at least one of the electrodes must be transparent, and a transparent electrode usually formed of a transparent conductor such as indium tin oxide (ITO) is used as an anode. Used.
  • ITO indium tin oxide
  • metal electrodes such as Mg—Ag and Al—Li are used.
  • the light emitting layer is formed of a very thin film having a thickness of about 10 nm. For this reason, the light emitting layer transmits light almost completely like the transparent electrode. As a result, the light that is incident from the surface of the transparent substrate when not emitting light, passes through the transparent electrode and the light emitting layer, and is reflected by the metal electrode again exits to the surface side of the transparent substrate.
  • the display surface of the EL display device looks like a mirror surface.
  • the circularly polarizing plate of this embodiment is suitable for an organic EL display device in which such external light reflection is particularly problematic.
  • the organic EL element 101 when the organic EL element 101 is not emitting light, external light incident from the outside of the organic EL element 101 due to indoor lighting or the like is absorbed by the polarizer 311 of the circularly polarizing plate 301 and the other half is transmitted as linearly polarized light. Then, the light enters the ⁇ / 4 film 316. Since the transmission axis of the polarizer 311 and the slow axis of the ⁇ / 4 film 316 are arranged to intersect at 45 ° (or 135 °), the light incident on the ⁇ / 4 film 316 is ⁇ / 4 By passing through the film 316, it is converted into circularly polarized light.
  • the phase is inverted by 180 degrees and reflected as reverse circularly polarized light. Since the reflected light is incident on the ⁇ / 4 film 316 and converted into linearly polarized light perpendicular to the transmission axis of the polarizer 311 (parallel to the absorption axis), all of the reflected light is absorbed by the polarizer 311 and emitted to the outside. Will not be. That is, external light reflection at the organic EL element 101 can be reduced by the circularly polarizing plate 301.
  • FIG. 6 is a cross-sectional view showing a schematic configuration of a display device 400 as a liquid crystal display device of the present embodiment.
  • the display device 400 is configured by disposing a polarizing plate 402 on one surface side of the display cell 401.
  • the display cell 401 can be a liquid crystal cell in which a liquid crystal layer is sandwiched between a pair of substrates. Note that, on the side opposite to the polarizing plate 402 with respect to the liquid crystal cell, another polarizing plate arranged in a crossed Nicols state with the polarizing plate 402 and a backlight for illuminating the liquid crystal cell are provided. These are not shown in the figure.
  • the display device 400 may have a front window 403 on the side opposite to the display cell 401 with respect to the polarizing plate 402.
  • the front window 403 is an exterior cover of the display device 400, and is made of, for example, a cover glass.
  • a filler 404 made of, for example, an ultraviolet curable resin is filled between the front window 403 and the polarizing plate 402.
  • an air layer is formed between the front window 403 and the polarizing plate 402. Therefore, reflection of light at the interface between the front window 403 and the polarizing plate 402 and the air layer causes a display image to be displayed. Visibility may be reduced.
  • the air layer is not formed between the front window 403 and the polarizing plate 402 by the filler 404, it is possible to avoid a decrease in visibility of the display image due to light reflection at the interface.
  • the polarizing plate 402 has a polarizer 501 that transmits predetermined linearly polarized light.
  • a ⁇ / 4 film 503 and a cured layer 504 made of an ultraviolet curable resin are laminated in this order via an adhesive layer 502. ing.
  • a protective film 506 is attached to the other surface side (display cell 401 side) of the polarizer 501 with an adhesive layer 505 interposed therebetween.
  • the polarizer 501 is obtained, for example, by staining a polyvinyl alcohol film with a dichroic dye and stretching it at a high magnification.
  • the polarizer 501 is subjected to alkali treatment (also referred to as saponification treatment), and then a ⁇ / 4 film 503 is bonded to one surface via an adhesive layer 502, and a protective film 506 is bonded to the other surface.
  • alkali treatment also referred to as saponification treatment
  • a ⁇ / 4 film 503 is bonded to one surface via an adhesive layer 502, and a protective film 506 is bonded to the other surface.
  • the thickness of the polarizer 501 is B ⁇ m, from the viewpoint of reducing the thickness of the polarizing plate 402, 1 ⁇ m ⁇ B ⁇ 20 ⁇ m It is desirable that 1 ⁇ m ⁇ B ⁇ 15 ⁇ m It is further desirable that
  • the adhesive layers 502 and 505 are layers made of, for example, a polyvinyl alcohol adhesive (PVA adhesive, water glue), but may be layers made of an ultraviolet curable adhesive (UV adhesive). These adhesives are liquid in a state where they are applied to an adhesive surface, and are bonded to each other by being dried or cured by ultraviolet irradiation after application. That is, the adhesive layers 502 and 505 adhere the polarizer 501 and the ⁇ / 4 film 503, and the polarizer 501 and the protective film 506, respectively, according to the state change from the liquid state. In this way, the adhesive layers 502 and 505 adhere the two by changing the state from the liquid state, and the adhesive layer (adhesive on the base material) that adheres the two without causing such a change in state.
  • the sheet-like adhesive layer ).
  • the ⁇ / 4 film 503 is a layer that imparts an in-plane retardation of about 1 ⁇ 4 of the wavelength to the transmitted light, and in the present embodiment, for example, contains a cellulose resin (cellulose polymer).
  • the ⁇ / 4 film 503 may contain a polycarbonate resin (polycarbonate polymer) instead of the cellulose polymer, or may contain a cycloolefin resin (cycloolefin polymer).
  • the ⁇ / 4 film 503 is a thin ⁇ / 4 film having a thickness of 10 ⁇ m to 70 ⁇ m.
  • the angle (crossing angle) between the slow axis of the ⁇ / 4 film 503 and the absorption axis of the polarizer 501 is 30 ° to 60 °, so that linearly polarized light from the polarizer 501 is ⁇ / It is converted into circularly polarized light or elliptically polarized light by the 4 film 503.
  • the cured layer 504 (also referred to as a hard coat layer) is composed of an active energy ray curable resin (for example, an ultraviolet curable resin).
  • the protective film 506 is composed of an optical film made of, for example, a cellulose resin (cellulose polymer), an acrylic resin, a cyclic polyolefin (COP), or a polycarbonate (PC).
  • the protective film 506 is simply provided as a film that protects the back side of the polarizer 501, but may be provided as an optical film that also serves as a retardation film having a desired optical compensation function.
  • another polarizing plate disposed on the side opposite to the polarizing plate 402 with respect to the display cell 401 is configured by sandwiching the surface of the polarizer between two optical films.
  • the polarizer and the optical film those similar to the polarizer 501 and the protective film 506 of the polarizing plate 402 can be used.
  • each of the polarizer 501 and the ⁇ / 4 film 503 described above may be long.
  • the long ⁇ / 4 film 503 is produced by oblique stretching to form a roll film, which is bonded to the roll polarizer 501 by a so-called roll-to-roll method to form a long film.
  • the polarizing plate 402 can be manufactured. Therefore, productivity can be dramatically improved and yield can be greatly improved as compared with the case where the polarizing plate 402 is manufactured by a batch method in which film pieces are bonded one by one.
  • an easy-adhesion layer for improving the adhesion of the ⁇ / 4 film 503 may be provided on the adhesive layer 502 side of the ⁇ / 4 film 503.
  • the easy adhesion layer is formed by performing an easy adhesion process on the adhesive layer 502 side of the ⁇ / 4 film 503.
  • Examples of the easy adhesion treatment include corona (discharge) treatment, plasma treatment, flame treatment, itro treatment, glow treatment, ozone treatment, primer coating treatment, and the like, and at least one of them may be performed.
  • corona treatment and plasma treatment are preferable as the easy adhesion treatment.
  • the long film 1 is a cellulose ester resin film and was produced by the following production method.
  • Fine particles (Aerosil R972V manufactured by Nippon Aerosil Co., Ltd.) 11 parts by weight Ethanol 89 parts by weight The above was stirred and mixed with a dissolver for 50 minutes, and then dispersed with Manton Gorin to prepare a fine particle dispersion 1.
  • Fine particle additive liquid Based on the following composition, the fine particle dispersion was slowly added to a dissolution tank containing methylene chloride with sufficient stirring. Further, the particles were dispersed by an attritor so that the secondary particles had a predetermined particle size. This was filtered through Finemet NF manufactured by Nippon Seisen Co., Ltd. to prepare a fine particle additive solution 1. 99 parts by mass of methylene chloride 5 parts by mass of fine particle dispersion 1
  • a main dope solution having the following composition was prepared. First, methylene chloride and ethanol were added to the pressure dissolution tank. Cellulose acetate was added to a pressurized dissolution tank containing a solvent while stirring. This was heated and stirred to dissolve completely, and this was dissolved in Azumi Filter Paper No. The main dope solution was prepared by filtration using 244. In addition, the compound synthesize
  • the inside of the Kolben was depressurized to 4 ⁇ 10 2 Pa or less, and after excess pyridine was distilled off at 60 ° C., the inside of the Kolben was depressurized to 1.3 ⁇ 10 Pa or less and the temperature was raised to 120 ° C. Most of the acid and benzoic acid formed were distilled off.
  • the ester compound has an ester of benzoic acid at the end of a polyester chain formed by condensation of 1,2-propylene glycol, phthalic anhydride and adipic acid.
  • the acid value of the ester compound was 0.10, and the number average molecular weight was 450.
  • the main dope solution was cast uniformly on a stainless steel belt support.
  • the solvent is evaporated until the residual solvent amount in the cast (cast) long film reaches 75%, peeled off from the stainless steel belt support, and transported by many rolls. Drying was terminated, and a long film 1 having a width of 1500 mm was obtained.
  • the long film 2 is a cycloolefin resin film (COP), and was produced by the following production method.
  • COP cycloolefin resin film
  • DCP dicyclopentadiene
  • MTF 9a-tetrahydrofluorene
  • MTD 8-methyl-tetracyclo [4.4.0.12, 5.17,10] -dodec-3-ene
  • a norbornene-based monomer mixture composed of parts and 40 parts by mass of tungsten hexachloride (0.7% toluene solution) were continuously added over 2 hours for polymerization.
  • 1.06 parts by mass of butyl glycidyl ether and 0.52 parts by mass of isopropyl alcohol were added to deactivate the polymerization catalyst and stop the polymerization reaction.
  • a soft polymer manufactured by Kuraray Co., Ltd .; Septon 2002
  • an antioxidant manufactured by Ciba Specialty Chemicals Co., Ltd .; Irganox 1010
  • cyclohexane and other volatile components which are solvents, are removed from the solution using a cylindrical concentration dryer (manufactured by Hitachi, Ltd.), and the hydrogenated polymer is extruded in a strand form from an extruder in a molten state. After cooling, it was pelletized and collected.
  • the obtained ring-opened polymer hydrogenated pellets were dried at 70 ° C. for 2 hours using a hot air dryer in which air was circulated to remove moisture.
  • the pellets were melted by using a short-shaft extruder having a coat hanger type T die (manufactured by Mitsubishi Heavy Industries, Ltd .: screw diameter 90 mm, T die lip member quality is tungsten carbide, peel strength 44N from molten resin).
  • Extrusion molding produced a cycloolefin polymer film. In extrusion molding, a long film 2 having a width of 1500 mm was obtained in a clean room of class 10,000 or less under molding conditions of a molten resin temperature of 240 ° C. and a T die temperature of 240 ° C.
  • the obliquely stretched film was widened in the heat setting zone Z3. That is, in the heat setting zone Z3, the width of the long diagonally stretched film before widening after the end of the diagonal stretching is L1 (mm), and in the heat setting step, from the portion corresponding to the width L1 of the diagonally stretched film before widening Also, when the widths of the widened portions on the leading side and the delay side are L2 (mm) and L3 (mm), respectively, the diagonally stretched so that the width L1, the width L2, and the width L3 are the values shown in Table 1. The film was widened. In Table 1, the ratio A and the ratio B represented by the following formula are also shown.
  • the temperature in the heat setting zone Z3 was adjusted to a temperature 30 ° C. lower than the temperature in the stretch zone Z2.
  • A (L2 / L1) ⁇ 100
  • B (L3 / L1) ⁇ 100
  • the obliquely stretched film of Comparative Example 1 In the production of the obliquely stretched film of Comparative Example 1, no widening was performed in the heat setting zone Z3. On the other hand, in the production of the obliquely stretched film of Comparative Example 2, the obliquely stretched film was widened not in the heat setting zone Z3 but in the stretching zone Z2. At this time, in the stretching zone Z2, the width of the long diagonally stretched film before widening is L1 (mm), and the portion widened to the leading side and the delay side than the portion corresponding to the width L1 of the diagonally stretched film before widening The width of each was L2 (mm) and L3 (mm), respectively.
  • the original film (long film 2) made of COP was also obliquely stretched in the same manner as described above. That is, first, in the vicinity of the front side of the heating zone Z, both ends of the unstretched film A sent from the film feeding unit 2 are used as the first clip as the preceding holding tool Ci and the holding tool Co on the delay side. Of the second clip. When the unstretched film A is gripped, the unstretched film A is gripped by moving the clip levers of the first and second clips with the clip closer. When gripping the clip, both ends of the unstretched film A are simultaneously gripped by the first and second clips, and the line connecting the grip positions at both ends is parallel to the axis parallel to the width direction of the film. Grab so that
  • the unstretched film A (long film 2) was obliquely stretched by the stretching portion 5 described above to obtain a long oblique stretched film (see Example 5 and Comparative Example 3 in Table 1). That is, the gripped unstretched film A is transported while being gripped by the first and second clips, and heated by passing through the preheating zone Z1, the stretching zone Z2, and the heat fixing zone Z3 in the heating zone Z, A stretched film A ′ stretched in an oblique direction with respect to the hand direction was obtained.
  • the obliquely stretched film of Example 5 was widened so that the width L1, the width L2, and the width L3 were values shown in Table 1 in the heat setting zone Z3.
  • the widening was performed in the stretching zone Z2 instead of the heat setting zone Z3. Note that the definitions of the width L1, the width L2, and the width L3 in Comparative Example 3 are the same as the definitions in Comparative Example 2 in which widening is performed in the stretching zone Z2.
  • the film moving speed during heating and stretching was 15 m / min.
  • the temperature of the preheating zone Z1 was 147 ° C.
  • the temperature of the stretching zone Z2 was 147 ° C.
  • the temperature of the heat setting zone Z3 was 140 ° C.
  • the stretching ratio of the film before and after stretching was 1.16 times, and the film thickness after stretching was 50 ⁇ m.
  • Circular polarizing plates 1 to 8 were produced as follows using a long obliquely stretched film obliquely stretched under the same conditions as described above.
  • a 120 ⁇ m-thick polyvinyl alcohol film was uniaxially stretched (temperature 110 ° C., stretch ratio 5 times), immersed in an aqueous solution composed of 0.075 g of iodine, 5 g of potassium iodide, and 100 g of water, and then potassium iodide. It was immersed in a 68 ° C. aqueous solution consisting of 6 g, boric acid 7.5 g, and water 100 g. The film after immersion was washed with water and dried to obtain a polarizer.
  • Circular polarizing plates 11 to 18 were prepared as follows using a long obliquely stretched film obliquely stretched under the same conditions as described above.
  • a 120 ⁇ m-thick polyvinyl alcohol film was uniaxially stretched (temperature 110 ° C., stretch ratio 5 times), immersed in an aqueous solution composed of 0.075 g of iodine, 5 g of potassium iodide, and 100 g of water, and then potassium iodide. It was immersed in a 68 ° C. aqueous solution consisting of 6 g, boric acid 7.5 g, and water 100 g. The film after immersion was washed with water and dried to obtain a polarizer.
  • the prepared long diagonally stretched films of Examples 1 to 5 and Comparative Examples 1 to 3 were bonded to one side of the polarizer using a 5% polyvinyl alcohol aqueous solution as an adhesive.
  • the lamination was performed so that the transmission axis of the polarizer and the slow axis of the obliquely stretched film were oriented at 45 °.
  • Konica Minolta Tack Film KC2CT1 manufactured by Konica Minolta Co., Ltd.
  • alkali saponification treatment was bonded in the same manner to the other surface of the polarizer to produce circularly polarizing plates 11-18.
  • calcium was deposited to a thickness of 4 nm by vacuum deposition as a first cathode having a low work function so that electrons can be efficiently injected onto the light emitting layer.
  • aluminum was formed to a thickness of 2 nm as a second cathode on the first cathode.
  • the aluminum used as the second cathode has a role of preventing the calcium as the first cathode from being chemically altered when the transparent electrode formed thereon is formed by sputtering. .
  • an organic light emitting layer was obtained.
  • a transparent conductive film having a thickness of 80 nm was formed on the cathode by sputtering.
  • ITO was used as the transparent conductive film.
  • 200 nm of silicon nitride was formed on the transparent conductive film by a CVD method (chemical vapor deposition method) to obtain an insulating film. This produced the organic EL element.
  • the size of the produced organic EL element was 1296 mm ⁇ 784 mm.
  • the circularly polarizing plates 1 to 8 prepared as described above are fixed on the insulating film of the organic EL element as described above with an adhesive so that the surface of the obliquely stretched film faces the surface of the insulating film of the organic EL element. Turn into. Thereby, the organic EL display devices 1 to 8 were produced.
  • the orientation angle in the width direction of the obliquely stretched film produced by the same method as in Examples 1 to 5 and Comparative Examples 1 to 3 in Table 1 is as follows. The difference between the left and right orientation angles was determined. That is, the obliquely stretched film was left in a room at 23 ° C. and 55% RH for 24 hours, and then 10 pieces of film pieces were cut out in the transport direction 30 mm inside from the end of the obliquely stretched film.
  • the orientation angle was measured at each position in the width direction using a phase difference measuring device (manufactured by Oji Scientific Co., Ltd., KOBRA-WXK). And the obtained average value was defined as the difference between the left and right orientation angles. Then, the orientation angle unevenness in the width direction was quantitatively evaluated based on the following evaluation criteria. "Evaluation criteria" A: The difference between the right and left orientation angles is less than 0.3 °. B: The difference between the right and left orientation angles is 0.3 ° or more and less than 0.6 °. C: The difference between the right and left orientation angles is 0.6 ° or more and less than 0.8 °. D: The difference between the right and left orientation angles is 0.8 ° or more.
  • the produced organic EL display devices 1 to 8 and liquid crystal display devices 1 to 8 were left in an environment of 60 ° C. and 90% RH for 500 hours, and then allowed to stand in an environment of 23 ° C. and 55% RH for 24 hours.
  • a black screen was displayed on the display device, and the color display state was visually observed and evaluated based on the following criteria.
  • the liquid crystal display devices 1 to 8 were visually observed with polarized sunglasses attached, and evaluated based on the following criteria.
  • B Slight striped unevenness was observed at the edge of the screen, but this is a level that does not cause a problem in practice.
  • C Thin striped unevenness was observed on the entire screen.
  • D Striped unevenness was observed on the entire screen.
  • Table 1 shows the evaluation results for the obliquely stretched films of Examples 1 to 5 and Comparative Examples 1 to 3.
  • the manufacturing method of the diagonally stretched film of this embodiment described above can be expressed as follows.
  • a heat fixing step for fixing the optical axis of the obliquely stretched film after the oblique stretching step is completed;
  • the heat setting step widening the obliquely stretched film after the oblique stretching step is completed, With the width of the obliquely stretched film before widening after the end of oblique stretching as L1, in the heat setting step, the width was widened to the leading side and the delay side from the portion corresponding to the width L1 of the obliquely stretched film before widening.
  • the present invention can be used, for example, for manufacturing a circularly polarizing plate for preventing external light reflection of an organic EL image display device.

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  • Engineering & Computer Science (AREA)
  • Mechanical 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)
  • Liquid Crystal (AREA)

Abstract

L'invention concerne un procédé de production d'un film étiré obliquement qui comprend une étape d'étirage oblique et une étape de fixation thermique. Au cours de l'étape d'étirage oblique, un film est transporté tandis que les deux extrémités du film dans le sens de la largeur du film sont saisies par une paire d'outils de préhension, un outil de préhension étant avancé relativement et l'autre outil de préhension étant retardé relativement, de manière à étirer le film dans une direction oblique par rapport au sens de la largeur. L'étape de fixation thermique est une étape destinée à fixer l'axe optique du film étiré obliquement à l'issue de l'étape d'étirage oblique. Lors de l'étape de fixation thermique, le film étiré obliquement à l'issue de l'étape d'étirage oblique est élargi. La largeur du film étiré obliquement, après avoir été étiré obliquement et avant d'être élargi, étant définie comme L1 et les largeurs respectives d'une section élargie vers le côté avancé et d'une section élargie vers le côté retardé lors de l'étape de fixation thermique, par rapport à une section correspondant à la largeur L1 du film étiré obliquement avant d'être élargi, étant définies comme L2 et L3, respectivement, la relation L3 > L2 ≥ 0 mm est satisfaite.
PCT/JP2016/055826 2015-03-20 2016-02-26 Procédé de production d'un film étiré obliquement WO2016152381A1 (fr)

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CN201680016798.6A CN107428070A (zh) 2015-03-20 2016-02-26 斜向拉伸膜的制造方法
KR1020177024621A KR102024448B1 (ko) 2015-03-20 2016-02-26 경사 연신 필름의 제조 방법
CN202210287977.0A CN114953408A (zh) 2015-03-20 2016-02-26 斜向拉伸膜的制造方法

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JPWO2019188857A1 (ja) * 2018-03-27 2021-03-25 日本ゼオン株式会社 長尺の延伸フィルム及び長尺の偏光フィルムの製造方法
JP7059429B1 (ja) 2021-09-10 2022-04-25 日東電工株式会社 延伸フィルムの製造方法および光学積層体の製造方法

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JP2022107944A (ja) * 2021-01-12 2022-07-25 コニカミノルタ株式会社 斜め延伸フィルムの製造方法

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WO2013145574A1 (fr) * 2012-03-30 2013-10-03 コニカミノルタ株式会社 Procédé et appareil permettant de produire un film étiré allongé

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WO2007111313A1 (fr) 2006-03-24 2007-10-04 Zeon Corporation Film etire continu, procede de production et utilisation du film etire
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JP2008080674A (ja) * 2006-09-28 2008-04-10 Nippon Zeon Co Ltd 延伸フィルムの製造方法、位相差フィルム、円偏光板、及び液晶表示装置
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WO2013145574A1 (fr) * 2012-03-30 2013-10-03 コニカミノルタ株式会社 Procédé et appareil permettant de produire un film étiré allongé

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JPWO2019188857A1 (ja) * 2018-03-27 2021-03-25 日本ゼオン株式会社 長尺の延伸フィルム及び長尺の偏光フィルムの製造方法
JP7124864B2 (ja) 2018-03-27 2022-08-24 日本ゼオン株式会社 長尺の延伸フィルム及び長尺の偏光フィルムの製造方法
JP2020049839A (ja) * 2018-09-27 2020-04-02 日本ゼオン株式会社 樹脂フィルムの製造方法、樹脂フィルム及び、複合フィルム
JP7103125B2 (ja) 2018-09-27 2022-07-20 日本ゼオン株式会社 樹脂フィルムの製造方法
JP7059429B1 (ja) 2021-09-10 2022-04-25 日東電工株式会社 延伸フィルムの製造方法および光学積層体の製造方法
JP2023040818A (ja) * 2021-09-10 2023-03-23 日東電工株式会社 延伸フィルムの製造方法および光学積層体の製造方法

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JP2020179671A (ja) 2020-11-05
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JPWO2016152381A1 (ja) 2018-01-11
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