WO2016147840A1 - Procédé de production d'un film étiré obliquement - Google Patents

Procédé de production d'un film étiré obliquement Download PDF

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WO2016147840A1
WO2016147840A1 PCT/JP2016/055864 JP2016055864W WO2016147840A1 WO 2016147840 A1 WO2016147840 A1 WO 2016147840A1 JP 2016055864 W JP2016055864 W JP 2016055864W WO 2016147840 A1 WO2016147840 A1 WO 2016147840A1
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Prior art keywords
film
width direction
group
temperature
stretching
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PCT/JP2016/055864
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English (en)
Japanese (ja)
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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 KR1020177024620A priority Critical patent/KR101973884B1/ko
Priority to JP2017506177A priority patent/JP6699655B2/ja
Priority to CN201680016162.1A priority patent/CN107428068B/zh
Publication of WO2016147840A1 publication Critical patent/WO2016147840A1/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
    • 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.
  • Patent Document 1 in order to reduce variation in optical characteristics, a film whose thickness is changed in advance in the width direction is prepared, and the film thickness is increased after the oblique stretching by stretching the film obliquely. An attempt is made to equalize in the width direction.
  • JP 2010-173261 A (refer to claim 1, paragraphs [0006] and [0010], FIGS. 1 to 4 etc.)
  • the present invention has been made to solve the above-described problems, and its purpose is to reduce the unevenness of the orientation angle in the width direction of the film even when the transport path is bent and oblique stretching is performed. It is possible to provide a method for producing an obliquely stretched film that can reduce color unevenness when applied to an OLED.
  • the temperature of the film is changed in the width direction when the arc-shaped bending of the transport path for stretching in the oblique direction starts earliest in the width direction of the film.
  • the temperature of the film starts when the oblique stretching starts earliest, that is, when the arcuate bending of the film transport path for stretching in the oblique direction starts earliest in the width direction of the film.
  • the width in the width direction it is possible to reduce the occurrence of uneven stretching in the width direction due to the shrinkage in the transport direction of the film that occurs during oblique stretching, and to reduce the occurrence of unevenness in the orientation angle in the width direction. be able to.
  • OLED organic EL display device
  • 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 represents a substituent.
  • substituent represented by R 1 , R 2 and R 3 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 groups (2-cyclopenten-1-yl, 2-cyclohexen-1-yl group, etc.), alkynyl groups (ethynyl group, propargyl group, etc.), ary
  • 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 represent 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 in Groups 14 to 16.
  • Z represents a nonmetallic atom group that forms a ring 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 ring 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 substitution degree of the acyl group can be measured according to ASTM-D817-96, which is one of the standards established 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 further 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 temperature of the film is changed in the width direction at the time when the arc-shaped bending of the conveyance path for stretching in the oblique direction starts earliest in the width direction of the film.
  • the bending of the conveyance path means that the conveyance path is bent in an arc shape, that is, the conveyance path is bent smoothly.
  • FIG. 3 schematically shows a state in which the film transport path (indicated by a thick solid arrow in the drawing) in the stretching section 5 is bent in the middle.
  • the film transport path is changed by adjusting the position and the degree of bending (curvature) of the rails Ri and Ro on which the pair of grippers Ci and Co that grip both ends in the width direction of the film travel. be able to.
  • the above-mentioned “time when the bending of the transport path for extending in the oblique direction starts” is the most upstream of the bent portions Q1 and Q2 of the rails Ri and Ro that are bent in an arc shape for performing the oblique extension.
  • the point in time when an arbitrary point of the film to be conveyed reaches the line connecting the points P1 and P2 on the side.
  • the film transport direction begins to bend in an arc shape and changes to the film discharge direction after oblique stretching. From this, "the point in time when the bending of the transport path for stretching in the oblique direction starts” means that the direction of the vector indicating the transport direction of the film is from the direction before oblique stretching toward the discharge direction after oblique stretching. It can be said that it starts to change.
  • the film may be subjected to lateral stretching (pre-stretching) or may not be laterally stretched. Also good.
  • FIG. 3 shows an example in which the bending of the conveyance path starts simultaneously in the width direction of the film (for all points in the width direction).
  • the time point at which the bending of the transport path for oblique stretching starts earliest in the width direction of the film refers to all the width directions of the film to be transported on the line connecting the points P1 and P2. This refers to the point in time when points arrive at the same time.
  • the timing at which the bending of the transport path starts may be different.
  • the point at which the bending of the conveyance path for oblique stretching starts earliest in the width direction of the film refers to the leading side of the film and the delay The point in time when one of the sides reaches the earliest (earliest) on the line connecting the points P1 and P2.
  • FIG. 4 shows another way of illustrating the extending portion 5 described above.
  • the film conveyance path in the stretching section 5 is illustrated as a thick solid line arrow, and the circle of the conveyance path from a position upstream of the line segment connecting the points Q11 and Q12. Arc-shaped bending begins.
  • the points Q11 and Q12 indicate points where the curvatures of the bent portions Q1 and Q2 shown in FIG.
  • the position (the line connecting the points P1 ′ and P2 ′) where the bending in the transport direction starts on the upstream side of the line connecting the points Q11 and Q12 is the position shown in FIG.
  • the temperature control in the width direction of the film of the present embodiment can be applied by considering it in association with the line segment connecting the points P1 and P2.
  • FIG. 5 shows an example of a detailed configuration of the stretching unit 5, and shows a configuration of the stretching unit 5 that is earlier than the delay side in the width direction of the film and has a timing at which the bending of the transport path starts earlier.
  • FIG. 5 shows schematically.
  • the leading side end of the leading side end and the delaying side end in the width direction of the film that is, the leading side end of the leading side in the width direction of the film starts first.
  • the film is heated by the heating unit 11 so that the film temperature is lower on the delay side than on the preceding side, thereby changing the film temperature in the width direction.
  • the heating unit 11 hot air is blown from the upper surface side or the lower surface side of the film, the temperature of the hot air is changed in the width direction of the film, the film is heated by an infrared heater, and the heating temperature is set to the film It is possible to adopt a method of changing in the width direction. Further, the number of heating units 11 may be singular or plural. That is, as shown in FIG. 5, the heating temperature may be changed in the width direction of the film by a single heating unit 11, or a plurality of heating units 11 having different outputs (heating ability) are arranged in the width direction, The heating temperature may be changed in the width direction.
  • a means for heating or cooling the opposite side with respect to the delay side or the leading side can be employed.
  • winds with different temperatures are blown between the delay side and the preceding side, the temperature of the wind is constant, and only one of the delay side and the leading side is heated by the heater, and the delay side and the leading side are used with a heater having a different temperature.
  • Various means such as heating the side are conceivable and are not particularly limited.
  • the leading side of the film transport path starts to bend earlier than the delayed side
  • the leading side starts to be obliquely stretched earlier than the delayed side of the film.
  • the leading side rather than the delay side of the film increases the region where the film thickness becomes relatively thick (in the film discharge direction) due to the early contraction in the transport direction in oblique stretching, so the leading side is more
  • the film is obliquely stretched, the film is less likely to stretch than the delay side.
  • the leading side of the film becomes softer because the temperature is relatively higher than the delay side, and during oblique stretching The film tends to stretch.
  • the delay side of the film becomes hard because the temperature is relatively lower than that of the preceding side, and the film becomes difficult to stretch during oblique stretching. Therefore, by changing the film temperature in the width direction at the start of bending of the transport path, that is, at the start of oblique stretching, the film that has been easily stretched due to the high temperature on the leading side is stretched by oblique stretching and delayed.
  • T1-T2 when the value of T1-T2 is larger than the upper limit, the effect of easily extending the leading side during oblique stretching is reduced, and the effect of reducing thickness unevenness in the width direction is reduced.
  • a more preferable range of T1-T2 is ⁇ 10 ° C. ⁇ (T1-T2) ⁇ ⁇ 2 ° C. It is.
  • the film temperature can measure with a non-contact temperature sensor.
  • the film temperature during stretching can be measured by using a heat-resistant non-contact temperature sensor (IRtec® Rayomatic® 14, manufactured by Utron Co., Ltd.).
  • the temperature range of heating and cooling is not particularly limited, and heating or cooling may be performed in a temperature range in which a desired in-plane retardation can be secured.
  • FIG. 6 shows another example of the stretching unit 5, and schematically illustrates the configuration of the stretching unit 5 that is earlier than the preceding side in the width direction of the film and has a timing at which the bending of the transport path starts earlier. It shows.
  • the delay-side end is the first among the delay-side end and the leading-side end in the width direction of the film, that is, when the bending of the transport path on the delay side in the width direction of the film starts.
  • the film is heated by the heating unit 11 so that the film temperature becomes higher on the delay side than on the preceding side, thereby changing the film temperature in the width direction.
  • the delay side of the film becomes softer because the temperature is relatively higher than the preceding side, and during oblique stretching The film tends to stretch.
  • the leading side of the film becomes hard because the temperature is relatively lower than that of the delay side, and the film is difficult to stretch during oblique stretching.
  • the film temperature in the width direction at the start of bending of the transport path that is, at the start of oblique stretching
  • the film that has been easily stretched due to the high temperature on the delay side is stretched by oblique stretching
  • On the side a film that is difficult to stretch due to low temperature is stretched by oblique stretching, so that the film does not cause uneven stretching during oblique stretching while suppressing an increase in film thickness (due to shrinkage in the transport direction) on the delay side.
  • the occurrence of stretching unevenness in the entire width direction can be reduced, and the occurrence of unevenness in the orientation angle in the width direction can be reduced.
  • T1-T2 when the value of T1-T2 is smaller than the lower limit, the effect of easily extending the delay side during oblique stretching is reduced, and the effect of reducing thickness unevenness in the width direction is reduced.
  • a more preferable range of T1-T2 is 2 °C ⁇ (T1-T2) ⁇ 9 °C It is.
  • FIG. 7 shows a further example of the stretching unit 5, and schematically shows the configuration of the stretching unit 5 at the same timing when the bending of the transport path starts in the width direction of the film.
  • the temperature of the film is in the width direction.
  • the film is heated by the heating unit 11 so as to be higher on the delay side than on the preceding side, thereby changing the temperature of the film in the width direction.
  • the delay side has a greater degree of bending in the oblique direction than the leading side of the film. For this reason, the degree of shrinkage in the transport direction in oblique stretching is greater on the delay side than on the preceding side of the film. For this reason, the film thickness becomes thicker on the delay side than on the preceding side of the film.
  • the delay side of the film becomes softer because the temperature is relatively higher than the preceding side, and during oblique stretching The film tends to stretch.
  • the leading side of the film becomes hard because the temperature is relatively lower than that of the delay side, and the film is difficult to stretch during oblique stretching.
  • the oblique stretching step when the oblique stretching is started, that is, when the arc-shaped bending of the film transport path for stretching in the oblique direction starts earliest in the width direction of the film.
  • the temperature of the film in the width direction By changing the temperature of the film in the width direction, it is possible to reduce the occurrence of uneven stretching in the width direction due to shrinkage in the transport direction of the film that occurs during oblique stretching.
  • the heating unit 11 is used to change the film temperature in two steps in the width direction.
  • the temperature control in the width direction is limited to the above two steps. I don't mean.
  • FIG. 8 shows still another example of the stretching unit 5, and schematically shows another configuration of the heating unit 11 disposed in the stretching unit 5.
  • the heating part 11 changes the heating temperature of the film stepwise in the width direction, it may be changed in four steps as shown in FIG. It may be changed.
  • which of the preceding side and the delay side in the width direction of the film is to be heated is set in accordance with the start timing of bending of the transport path on the leading side and the delay side, as described above. do it.
  • FIG. 9 schematically shows still another configuration of the heating unit 11 arranged in the stretching unit 5.
  • the heating unit 11 may continuously change the heating temperature of the film in the width direction.
  • the film temperature is continuously changed in the width direction by continuously changing the temperature and air volume of the hot air blown from the heating unit 11 in the width direction or continuously changing the amount of infrared irradiation in the width direction. Can be changed.
  • the film to be obliquely stretched in this embodiment may be a film containing a cellulose resin (such as the cellulose ester resin described above).
  • a cellulose resin such as the cellulose ester resin described above.
  • film thickness unevenness and alignment angle unevenness in the width direction can be reduced by performing oblique stretching on the film containing the cellulose-based resin while performing the above-described temperature control in the width direction.
  • the film conveyance speed may be 1 to 150 m / min. From the viewpoint of reliably changing the temperature in the width direction by heating the film and improving the productivity of the film.
  • the conveyance speed of the film is 5 to 120 m / min, preferably 20 to 100 m / min.
  • 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. 10 is a cross-sectional view illustrating 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. 11 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. At this time, the film thickness of the long film 1 was 67 ⁇ m.
  • 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).
  • a cycloolefin polymer film having a thickness of 75 ⁇ m was produced by extrusion molding. 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.
  • Diagonal stretching was performed by the following method using the long film 1 made of the cellulose-based resin produced above. That is, the long film 1 (raw film) of the cellulose-based resin obtained above is subjected to temperature in the width direction of the film at the start of oblique stretching using the stretching portions 5 shown in FIGS. The film was stretched obliquely while giving a change to obtain a long obliquely stretched film (see Examples 1 to 10 in Table 1).
  • the moving speed of the film is 15 m / min or 40 m / min
  • the temperature of the preheating zone Z1 is 200 ° C.
  • the temperature of the stretching zone Z2 is 200 ° C.
  • the temperature of the heat setting zone Z3 is 160 ° C.
  • the stretching ratio is 1. 16 times
  • the thickness was 58 ⁇ m
  • the final film width after trimming was 1300 mm.
  • a slanted stretched film was obtained without performing heating by the heating part 11 (see Comparative Examples 1 to 5 in Table 1).
  • 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 film was obliquely stretched while giving a temperature change in the width direction of the film at the start of oblique stretching to obtain a long obliquely stretched film (Examples in Table 1). 11-12). 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. For comparison, in the stretching section 5 of FIGS. 5 and 7, slanting stretching was performed without heating by the heating section 11 to obtain a long oblique stretched film (see Comparative Examples 6 to 7 in Table 1).
  • the film moving speed during heating and stretching was set to 40 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 stretch ratio of the film before and after stretching was 1.16 times
  • the thickness of the film after stretching was 58 ⁇ m.
  • a raw film (cellulose ester resin film) having such a film thickness that the film thickness after stretching is 40 ⁇ m is produced in the same manner as the long film 1.
  • the raw film was produced by the method, and the film was stretched obliquely under the same stretching conditions as in Example 7 (except that the temperature of the preheating zone and the temperature of the stretching zone were 198 ° C.) and the film moving speed (15 m / min).
  • a long diagonally stretched film having a thickness of 40 ⁇ m was obtained (see Example 14 in Table 1).
  • Example 15 using the same raw film as used in Example 14, except that the film moving speed during oblique stretching was changed to 5 m / min, oblique stretching was performed under the same stretching conditions as in Examples 7 and 14, A long diagonally stretched film was obtained (see Example 15 in Table 1).
  • the temperature described in each of the above examples is a zone temperature, not a film temperature.
  • Circular polarizing plates 1 to 15 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 slanted stretched films of Examples 1 to 15 were bonded to one side of the polarizer using a 5% aqueous solution of polyvinyl alcohol as an adhesive. At that time, 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 °. Then, Konica Minolta-tack film KC4UAH (manufactured by Konica Minolta Co., Ltd.) subjected to alkali saponification treatment was similarly bonded to the other surface of the polarizer to produce circularly polarizing plates 1 to 15.
  • Konica Minolta-tack film KC4UAH manufactured by Konica Minolta Co., Ltd.
  • Circular polarizing plates 16 to 30 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.
  • the prepared slanted stretched films of Examples 1 to 15 were bonded to one side of the polarizer using a 5% aqueous solution of polyvinyl alcohol 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. subjected to alkali saponification treatment was bonded in the same manner to the other surface of the polarizer to produce circularly polarizing plates 16-30.
  • a reflective electrode made of chromium having a thickness of 80 nm was formed on a glass substrate by sputtering.
  • ITO indium tin oxide
  • PEDOT poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate
  • PEDOT poly(3,4-ethylenedioxythiophene) -polystyrene sulfonate
  • PEDOT poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate
  • each of the RGB light emitting layers was formed to a thickness of 100 nm on the hole transport layer using a shadow mask.
  • 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 15 prepared as described above are fixed with an adhesive on the insulating film of the organic EL element manufactured as described above so that the surface of the obliquely stretched film faces the surface of the insulating film of the organic EL element. Turn into. Thus, organic EL display devices 1 to 15 were produced.
  • the orientation angle is measured at intervals of 25 mm in the width direction of the long obliquely stretched film using a phase difference measuring device (manufactured by Oji Scientific Co., Ltd., KOBRA-WXK). The difference between the angle and the minimum value was defined as the variation (°) in the orientation angle ⁇ . Then, the orientation angle unevenness in the width direction was quantitatively evaluated based on the following evaluation criteria. "Evaluation criteria" AA: The variation in the orientation angle in the width direction is less than 0.3 °. A: The variation in the orientation angle in the width direction is 0.3 ° or more and less than 0.4 °.
  • B The variation in the orientation angle in the width direction is 0.4 ° or more and less than 0.6 °.
  • C Variation in the orientation angle in the width direction is 0.6 ° or more and less than 0.8 °.
  • D The variation in the orientation angle in the width direction is 0.8 ° or more.
  • Table 1 shows the results of evaluation of the orientation angle unevenness performed on the obliquely stretched films of Examples 1 to 15 and Comparative Examples 1 to 7.
  • stretching methods 1 to 3 correspond to the stretching methods in FIGS. 5 to 7, respectively. That is, the stretching method 1 refers to an oblique stretching method in which the leading side bending timing is earlier than the delay side of the film, and the stretching method 2 refers to an oblique stretching method in which the delay side bending timing is earlier than the leading side of the film, The stretching method 3 indicates an oblique stretching method in which the bending timing is the same in the entire width direction of the film.
  • the width temperature difference refers to the difference between the temperature at the most delay side position and the temperature at the most preceding side position in the film width direction, and each of the above temperatures is the temperature at the hot air blowing section of the heating section. Point to.
  • the width temperature difference was measured using the above-mentioned heat-resistant non-contact temperature sensor (IRtec Rayomatic 14 manufactured by Utron, Inc.).
  • the width temperature difference described in Table 1 is a temperature difference of the film measured by the above method, and is not a temperature difference of each zone of the stretched portion.
  • no temperature difference adjustment refers to the temperature distribution when the film is not heated in the width direction and no temperature change is given (FIG. 12). reference).
  • the delay side low temperature refers to the temperature distribution when the film is heated by changing the heating temperature in two steps in the width direction so that the delay side is lower than the preceding side (solid line in FIG. 13). See the graph).
  • the leading side low temperature refers to a temperature distribution when the film is heated by changing the heating temperature in two steps in the width direction so that the leading side is cooler than the delay side (broken line in FIG. 13). See the graph).
  • the delay side low temperature refers to the temperature distribution when the film is heated by changing the heating temperature in four steps in the width direction so that the delay side is lower than the preceding side (solid line in FIG. 14). See the graph).
  • the leading side low temperature refers to a temperature distribution when the film is heated by changing the heating temperature in four steps in the width direction so that the leading side is cooler than the delay side (broken line in FIG. 14). See the graph).
  • the temperature difference in the width direction is ⁇ 3.3 ° C. or less, which is smaller than ⁇ 0.9 ° C. in Example 1 (the delay side). It is desirable that the orientation angle unevenness in the width direction can be further reduced.
  • the temperature difference in the width direction is 1 ° C. or more, which is larger than 0.8 ° C. in Example 2 (the delay side is the leading side). Can be said to be desirable in that it can further reduce the orientation angle unevenness in the width direction.
  • the temperature difference in the width direction is 1 ° C. or more, which is larger than 0.7 ° C. in Example 3 (the delay side is more advanced). It is desirable that the orientation angle unevenness in the width direction can be further reduced.
  • Example 7 Even if the film moving speed during oblique stretching is further reduced from 15 m / min to 5 m / min, by giving a temperature change in the width direction of the film at the start of oblique stretching, It can be seen that the alignment angle unevenness in the width direction can be sufficiently reduced.
  • Example 7 and Example 14 even in a thin film, by giving a temperature change in the width direction of the film at the start of oblique stretching, the orientation angle unevenness in the width direction can be sufficiently reduced. From the results of Example 15, the film moving speed is slow and even a thin film can sufficiently reduce the orientation angle unevenness in the width direction by giving a temperature change in the width direction of the film at the start of oblique stretching. Recognize.
  • the circularly polarizing plates 1 to 15 were produced using the obliquely stretched films produced in Examples 1 to 15, and the produced circularly polarizing plates 1 to 15 were applied for preventing reflection of external light. It was confirmed that color unevenness on the screen was reduced.
  • the circularly polarizing plates 16 to 30 were produced using the obliquely stretched films produced in Examples 1 to 15, and the liquid crystal display devices 1 to 15 produced using the circularly polarizing plates 16 to 30 displayed a black screen.
  • the screen was uniformly displayed in black, and it was confirmed that the color unevenness due to the reflected light amount unevenness was not observed.
  • the manufacturing method of the diagonally stretched film of this embodiment described above can be expressed as follows.
  • the both ends of the film in the width direction are gripped by a pair of gripping tools, one gripping tool is relatively advanced, the other gripping tool is relatively delayed to transport the film, and the film transport path Is a method for producing an obliquely stretched film having an oblique stretching step of stretching the film in an oblique direction with respect to the width direction by bending the film into an arc shape,
  • the oblique stretching step the temperature of the film is changed in the width direction when the arcuate bending of the transport path for stretching in the oblique direction starts earliest in the width direction of the film.
  • 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)
  • Shaping By String And By Release Of Stress In Plastics And The Like (AREA)
  • Polarising Elements (AREA)
  • Manufacture Of Macromolecular Shaped Articles (AREA)

Abstract

L'invention concerne un procédé de production de film étiré obliquement, comprenant une étape d'étirage oblique pour étirer un film dans un sens oblique par rapport au sens de la largeur en saisissant les deux extrémités du film dans le sens de la largeur avec une paire d'outils de préhension, de transport du film en faisant avancer relativement l'un des éléments de préhension et en retardant relativement l'autre, et en pliant le trajet de transport du film en un arc Dans l'étape d'étirage oblique, la température du film est amenée à varier dans le sens de la largeur au le plus précoce au niveau duquel le pliage arqué du trajet de transport commence dans le sens de la largeur du film afin de l'étirer obliquement.
PCT/JP2016/055864 2015-03-17 2016-02-26 Procédé de production d'un film étiré obliquement WO2016147840A1 (fr)

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JP2018106061A (ja) * 2016-12-27 2018-07-05 コニカミノルタ株式会社 斜め延伸用原反フィルム及びその製造方法、並びに斜め延伸フィルムの製造方法
JP2019174636A (ja) * 2018-03-28 2019-10-10 コニカミノルタ株式会社 斜め延伸フィルム、偏光板、異形表示装置および斜め延伸フィルムの製造方法
JP7048814B1 (ja) 2021-11-18 2022-04-05 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
CN115122621A (zh) * 2021-03-26 2022-09-30 日东电工株式会社 延伸膜的制造方法

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JP7119377B2 (ja) * 2018-01-10 2022-08-17 コニカミノルタ株式会社 延伸フィルムおよびその製造方法

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WO2013146397A1 (fr) * 2012-03-29 2013-10-03 コニカミノルタ株式会社 Procédé de fabrication de film étiré obliquement de grande longueur
JP2013208771A (ja) * 2012-03-30 2013-10-10 Konica Minolta Inc 長尺斜め延伸フィルムの製造装置及び製造方法
WO2013161581A1 (fr) * 2012-04-25 2013-10-31 コニカミノルタ株式会社 Procédé de fabrication d'un film étiré obliquement
WO2014073019A1 (fr) * 2012-11-06 2014-05-15 コニカミノルタ株式会社 Procédé de production de film à étirage longitudinal
JP2014237287A (ja) * 2013-06-10 2014-12-18 コニカミノルタ株式会社 長尺斜め延伸フィルムの製造方法

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