WO2023189797A1 - Procédé de fabrication de film polarisant - Google Patents

Procédé de fabrication de film polarisant Download PDF

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Publication number
WO2023189797A1
WO2023189797A1 PCT/JP2023/010809 JP2023010809W WO2023189797A1 WO 2023189797 A1 WO2023189797 A1 WO 2023189797A1 JP 2023010809 W JP2023010809 W JP 2023010809W WO 2023189797 A1 WO2023189797 A1 WO 2023189797A1
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WO
WIPO (PCT)
Prior art keywords
polarizing film
film
transparent protective
protective film
polarizing
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PCT/JP2023/010809
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English (en)
Japanese (ja)
Inventor
慎太朗 三木
勝則 高田
亮 菅野
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日東電工株式会社
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Application filed by 日東電工株式会社 filed Critical 日東電工株式会社
Publication of WO2023189797A1 publication Critical patent/WO2023189797A1/fr

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements

Definitions

  • polarizing films used in various image display devices such as liquid crystal display devices and organic EL display devices have been dyed (using iodine, dichroic dyes, etc.) because they have both high transmittance and high degree of polarization.
  • a polyvinyl alcohol film (containing a dichroic substance) is used.
  • the polarizing film is manufactured by subjecting a polyvinyl alcohol film to various treatments such as swelling, dyeing, crosslinking, and stretching in a bath, followed by washing and drying.
  • the polarizing film is usually used as a polarizing film (polarizing plate) in which a transparent protective film such as triacetyl cellulose is bonded to one or both sides of the polarizing film using an adhesive.
  • the adhesive layer or pressure-sensitive adhesive layer tends to accumulate moisture, so light peeling is difficult at these interfaces. Therefore, there is a concern that display defects may easily occur in image display devices using such polarizing films.
  • the method for producing a polarizing film specifically disclosed in Patent Document 2 has a problem in that the adhesive strength between the polarizing film and the transparent protective film is weak, and the method for producing a polarizing film specifically disclosed in Patent Documents 3-5 Since the manufacturing method requires a bonding step at a high temperature of 135° C., there is a problem in that the resulting polarizing film may curl.
  • the present invention provides a method for producing a polarizing film in which a polarizing film and a transparent protective film are directly bonded without an adhesive layer or an adhesive layer, the method comprising: A step of manufacturing a laminate by irradiating at least one bonding surface with ultraviolet light and then bonding the polarizing film and the transparent protective film via a volatile medium;
  • the present invention relates to a method for manufacturing a polarizing film, which includes a step of drying the volatile medium by heating a laminate obtained by heating the polarizing film and bonding the polarizing film and the transparent protective film.
  • the method for producing a polarizing film of the present invention is a method for producing a polarizing film in which a polarizing film and a transparent protective film are directly bonded to each other without an adhesive layer or an adhesive layer.
  • the polarizing film and the transparent protective film can be directly bonded without using an adhesive layer or an adhesive layer. Since the diffusion of dichroic substances is suppressed, humidification reliability is also excellent.
  • the method for producing a polarizing film of the present invention is a method for producing a polarizing film in which a polarizing film and a transparent protective film are directly bonded to each other without an adhesive layer or an adhesive layer interposed therebetween.
  • the polarizing film is formed by adsorbing and aligning a dichroic substance such as iodine or a dichroic dye onto a polyvinyl alcohol film.
  • the polarizing film is preferably an iodine-based polarizing film containing iodine as the dichroic substance from the viewpoint of initial polarization performance of the polarizing film.
  • the polarizing film is obtained by a conventional method for producing a polarizing film, for example, by subjecting the polyvinyl alcohol film to an optional swelling process and washing process, and at least a dyeing process, a crosslinking process, and a stretching process. .
  • the thickness of the polarizing film is preferably 1 ⁇ m or more, more preferably 2 ⁇ m or more, from the viewpoint of improving the initial polarization degree of the polarizing film, and 15 ⁇ m or less from the viewpoint of preventing panel warpage.
  • the thickness is preferably 10 ⁇ m or less, more preferably 8 ⁇ m or less.
  • the following thin film is used, in which a laminate including a polyvinyl alcohol resin layer formed on a thermoplastic resin base material is used as the polyvinyl alcohol film. A method for manufacturing a polarizing film can be applied.
  • Polyamide resins such as group polyamides, polyimide resins, polyolefin resins such as polyethylene, polypropylene, and ethylene-propylene copolymers, (meth)acrylic resins, cyclic polyolefin resins having a cyclo or norbornene structure (norbornene resins) ), polyarylate resins, polystyrene resins, polyvinyl alcohol resins, and mixtures thereof.
  • the transparent protective film may include a cured layer formed from a thermosetting resin or an ultraviolet curable resin such as (meth)acrylic, urethane, acrylic urethane, epoxy, silicone, or the like.
  • cellulose ester resins, polycarbonate resins, (meth)acrylic resins, cyclic polyolefin resins, and polyester resins are preferred.
  • the thickness of the transparent protective film can be determined as appropriate, but generally from the viewpoint of strength, workability such as handleability, thin layer property, etc., it is preferably about 1 to 500 ⁇ m, and about 1 to 300 ⁇ m. The thickness is more preferably about 5 to 100 ⁇ m.
  • the transparent protective films on both sides may be the same or different.
  • a retardation plate having a front retardation of 40 nm or more and/or a thickness direction retardation of 80 nm or more can be used.
  • the frontal retardation is usually controlled in the range of 40 to 200 nm
  • the thickness direction retardation is usually controlled in the range of 80 to 300 nm.
  • the retardation plate also functions as a transparent protective film, so that it is possible to reduce the thickness.
  • the retardation plate examples include a birefringent film formed by uniaxially or biaxially stretching a polymer material, an oriented film of a liquid crystal polymer, and an oriented layer of a liquid crystal polymer supported by a film.
  • the thickness of the retardation plate is not particularly limited, but is generally about 1 to 150 ⁇ m.
  • the phase plate may be used by bonding it to a transparent protective film that does not have a phase difference.
  • the transparent protective film may contain any suitable additives such as ultraviolet absorbers, antioxidants, lubricants, plasticizers, mold release agents, color inhibitors, flame retardants, antistatic agents, pigments, colorants, etc. You can stay there. In particular, when the transparent protective film contains an ultraviolet absorber, the light resistance of the polarizing film can be improved.
  • a hard coat layer such as a hard coat layer, an anti-reflection layer, an anti-sticking layer, a diffusion layer or an anti-glare layer can be provided on the surface of the transparent protective film on which the polarizing film is not attached.
  • a hard coat layer such as a hard coat layer, an anti-reflection layer, an anti-sticking layer, a diffusion layer or an anti-glare layer
  • other layers such as the hard coat layer, antireflection layer, antisticking layer, diffusion layer, and antiglare layer can be provided on the protective film itself, or may be provided separately from the protective film. You can also do it.
  • the method for producing a polarizing film of the present invention includes surface-treating the bonding surface of at least one of the polarizing film and the transparent protective film by irradiating ultraviolet light, and then bonding the polarizing film and the transparent protective film.
  • the wavelength of the above-mentioned ultraviolet light is preferably 250-100 nm, more preferably 200-100 nm, and among them, a wavelength of 172 nm using a xenon excimer lamp is particularly preferable from the viewpoint of mass productivity. .
  • the illumination intensity of the ultraviolet light is preferably 1 mW/cm 2 or more, more preferably 50 mW/cm 2 or more from the viewpoint of processing capacity.
  • the cumulative light amount is preferably 1 mJ/cm 2 or more from the viewpoint of adhesiveness, more preferably 50 mJ/cm 2 or more, and 5000 mJ/cm 2 or less from the viewpoint of damage to the film. It is preferable that it is, and it is more preferable that it is 2000 mJ/cm 2 or less.
  • the temperature at the time of ultraviolet light irradiation is not particularly limited, and from the viewpoint of stabilizing surface modification, it is preferably about 0 to 50 °C, more preferably about 10 to 40 °C, and the polarizing film For production purposes, it is convenient to use room temperature. Further, the atmosphere during ultraviolet light irradiation only needs to have an oxygen concentration of 21% or less, and from the viewpoint of processing efficiency, the oxygen concentration is preferably 7.0% or less.
  • the volatile medium is not particularly limited, and from the viewpoint of drying efficiency, solvents such as water, ethanol, toluene, cyclohexane, acetone, etc. are preferred, and from the viewpoint of the environment, water is more preferred.
  • the heating temperature may be sufficient as long as it can appropriately dry the volatile medium; for example, when the volatile medium is water, it is preferably about 40 to 80°C, more preferably about 50 to 70°C. .
  • the drying time cannot be absolutely determined because it is affected by the temperature of the polarizing film, it is preferably about 1 minute to 60 minutes, more preferably about 3 minutes to 15 minutes.
  • the drying step may be performed only once, or may be performed multiple times as necessary.
  • the above lamination can be performed using a roll laminator or the like.
  • the bonding interface between the polarizing film and the transparent protective film may include a modified layer or a high elastic layer resulting from the treatment during bonding.
  • the adhesive force (peel strength) between the transparent protective film and the polarizing film is 0.5 N/15 mm or more when peel strength is measured at a peel angle of 90° and a peel rate of 1000 mm/min. It is preferably 1.0 N/15 mm or more, more preferably 1.2 N/15 mm or more.
  • the change ratio of the adhesive strength of the bonding surface between the polarizing film and the transparent protective film before and after being immersed in 20°C water for 24 hours is the peeling rate.
  • it is preferably 0.5 or more, and more preferably 0.7 or more.
  • Example 1> ⁇ Preparation of polarizing film> A laminate in which a 9 ⁇ m thick PVA layer was formed on an amorphous PET base material was subjected to auxiliary stretching in the air at a stretching temperature of 130°C to produce a stretched laminate, and then the stretched laminate was dyed to produce a colored laminate. Then, the colored laminate was stretched in boric acid water at a stretching temperature of 65 degrees to obtain an optical film containing a 5 ⁇ m thick polarizing film, which was stretched together with the amorphous PET base material so that the total stretching ratio was 5.94 times. A laminate was produced.
  • the PVA molecules of the PVA layer formed on the amorphous PET base material are highly oriented, and the iodine adsorbed by dyeing is oriented in one direction as a polyiodine ion complex.
  • An optical film laminate containing a polarizing film with a thickness of 5 ⁇ m was obtained.
  • the PET base material of the polarizing film to which the above-mentioned polarizing film and transparent protective film were directly bonded was peeled off, and a double-sided tape (No. 500, manufactured by Nitto Denko Corporation) was bonded to the peeled surface. Furthermore, the polarizing film was cut out to a size of 200 mm in parallel to the stretching direction and 15 mm in the orthogonal direction, and a cut was made between the polarizing film and the transparent protective film using a cutter knife, and then the release film of the double-sided tape was peeled off and the adhesive was removed. The drug surface was attached to a glass plate.
  • the polarizing film and the transparent protective film were peeled in a 90 degree direction at a peeling speed of 1000 mm/min using a flexible angle adhesive/film peeling analyzer (VPA-2, manufactured by Kyowa Interface Science Co., Ltd.), and the peel strength (N/15 mm) was measured. ) was measured.
  • VPN-2 flexible angle adhesive/film peeling analyzer
  • the PET base material of the polarizing film to which the above-mentioned polarizing film and transparent protective film were directly bonded was peeled off, and a double-sided tape (No. 500, manufactured by Nitto Denko Corporation) was bonded to the peeled surface. Furthermore, the polarizing film was cut out to a size of 200 mm in parallel to the stretching direction and 15 mm in the orthogonal direction, and a cut was made between the polarizing film and the transparent protective film using a cutter knife, and then the release film of the double-sided tape was peeled off and the adhesive was removed. The drug surface was attached to a glass plate.
  • the polarizing film bonded to the obtained glass plate was immersed in water at 20° C. for 24 hours, taken out, and excess moisture was removed.
  • the adhesive strength before and after immersion in water the polarizing film and transparent protective film were peeled in a 90-degree direction at a peeling speed of 1000 mm/min using a flexible angle adhesive/film peeling analyzer (VPA-2, manufactured by Kyowa Interface Science Co., Ltd.). Then, the peel strength (N/15 mm) was measured, and the change ratio (adhesion strength after dipping/adhesion strength before dipping) of the adhesive strength (peel strength) of the bonding surface was calculated.
  • those with a curl of less than 2 mm are indicated by ⁇
  • those with a curl of 2 mm or more but less than 3 mm are indicated by ⁇
  • those with a curl of 3 mm or more and less than 5 mm are indicated by ⁇
  • those with a curl of 5 mm or more are indicated by ⁇ .
  • the polarizing film was laminated to one side of a 0.7 mm thick alkali-free glass via an adhesive layer (thickness 20 ⁇ m) on the polarizing film side (humidification durability test evaluation sample) was prepared.
  • the transmittance Ts of the obtained polarizing film was measured using an ultraviolet-visible spectrophotometer (V-7100 manufactured by JASCO Corporation), and the single transmittance Ts, parallel transmittance Tp, and orthogonal transmittance Tc were determined for the polarizing film.
  • Ts, Tp and Tc of These Ts, Tp, and Tc are Y values measured using a 2-degree visual field (C light source) according to JIS Z8701 and subjected to visibility correction.
  • ⁇ T (%) is preferably 0.4 or less, more preferably 0.3 or less.
  • Example 2 A polarizing film in which a polarizing film and a transparent protective film were directly bonded was prepared in the same manner as in Example 1, except that a 13 ⁇ m thick cycloolefin resin film (Nippon Zeon Co., Ltd., ZF14) was used as the transparent protective film. I got it.
  • Example 3 As a transparent protective film, the following polycarbonate resin films with a thickness of 20 ⁇ m were used, and a polarizing film and a A polarizing film to which a transparent protective film was directly bonded was obtained.
  • a polycarbonate resin film was produced as follows. That is, 81.98 parts by mass of isosorbide was reacted with 47.19 parts by mass of tricyclodecane dimethanol, 175.1 parts by mass of diphenyl carbonate, and 0.979 parts by mass of a 0.2% by mass aqueous solution of cesium carbonate as a catalyst.
  • the mixture was placed in a container, and as the first step of the reaction, the heating tank temperature was heated to 150° C., and the raw materials were dissolved with stirring as necessary (about 15 minutes).
  • the pressure was raised from normal pressure to 13.3 kPa, and the temperature of the heating tank was raised to 190° C. over 1 hour, while the generated phenol was extracted out of the reaction vessel.
  • the pressure inside the reaction vessel was set to 6.67 kPa, and the heating tank temperature was raised to 230°C in 15 minutes to remove the generated phenol. It was taken out of the reaction vessel. As the stirring torque of the stirrer increased, the temperature was raised to 250° C.
  • the obtained polycarbonate resin was vacuum-dried at 80°C for 5 hours, and then put into a single-screw extruder (manufactured by Toshiba Machine Co., Ltd., cylinder set temperature: 250°C), a T-die (width 300mm, set temperature: 250°C), a chill roll ( An optical film made of polycarbonate resin was produced using a film forming apparatus equipped with a winder and a set temperature of 120 to 130°C.
  • ⁇ Comparative example 1> As a transparent protective film, the following active energy ray-curable adhesive was applied with a bar coater to a 23 ⁇ m thick cycloolefin resin film (Nippon Zeon Co., Ltd., ZF12), and a laminator was used to apply the adhesive obtained in Example 1. The film was bonded to the polarizing film surface of an optical film laminate containing a polarizing film with a thickness of 5 ⁇ m. In this state, active energy rays were irradiated from the transparent protective film side to cure the adhesive, thereby obtaining a polarizing film in which the transparent protective film was bonded to the polarizing film via the active energy ray adhesive.
  • [Active energy ray curable adhesive] 16.5 parts by weight of 2-hydroxyethyl acrylamide (manufactured by KJ Chemicals, trade name: HEAA), 1 part by weight of 4-vinylphenylboronic acid (manufactured by Tokyo Chemical Industry Co., Ltd.), 2-hydroxy-3-phenoxypropyl acrylate (manufactured by Toa) 30.5 parts by weight of 1,9-nonanediol diacrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name: Aronix M-5700), 25 parts by weight of 1,9-nonanediol diacrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name: Light Acrylate 1,9ND-A), hydroxypivalic acid 13 parts by weight of diacrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name: Light Acrylate HPP-A), 15 parts by weight of oligomer formed by poly
  • ⁇ Comparative example 2> A 40 ⁇ m thick cycloolefin resin film (Nippon Zeon Co., Ltd., ZF14) was laminated on one side of a 30 ⁇ m polarizing film (polyvinyl alcohol film) using a roll laminator at a temperature of 145°C. A polarizing film in which the membrane and resin film were directly bonded was obtained.
  • ⁇ Comparative example 3> In a nitrogen-substituted atmosphere with an oxygen concentration of about 2.5%, the polarizing film surface of the optical film laminate containing the polarizing film obtained above and a 23 ⁇ m thick cycloolefin resin film (Zeon Excimer UV light (wavelength 172 nm, peak illuminance 75 mW/cm 2 , cumulative light intensity 450 mJ/ cm 2 ) to perform surface modification. Subsequently, water was applied to the surface-modified surface of each film, and the water was air-dried. Subsequently, the polarizing film and the transparent protective film were bonded together using a laminator to obtain a polarizing film in which the polarizing film and the transparent protective film were directly bonded.
  • cycloolefin resin film Zeon Excimer UV light (wavelength 172 nm, peak illuminance 75 mW/cm 2 , cumulative light intensity 450 mJ/ cm 2 )
  • Example 1 The same evaluation as in Example 1 was performed using the polarizing films obtained in each of the above Examples and Comparative Examples. The results are shown in Table 1.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Polarising Elements (AREA)

Abstract

L'invention concerne un procédé de fabrication d'un film polarisant dans lequel une membrane polarisante et un film protecteur transparent sont directement joints sans utiliser une couche adhésive sensible à la pression ou une couche adhésive, le procédé de fabrication d'un film polarisant comprenant : une étape de production d'un corps stratifié par irradiation d'une surface de fixation d'au moins l'une de la membrane polarisante et du film protecteur transparent avec une lumière ultraviolette pour effectuer un traitement de surface de celle-ci, puis fixation de la membrane polarisante et du film protecteur transparent par l'intermédiaire d'un solvant volatil ; et une étape de chauffage du corps stratifié résultant et ainsi de séchage du solvant volatil pour joindre la membrane de polarisation et le film de protection transparent. Ce procédé de fabrication d'un film polarisant peut supprimer le gondolage et présente une excellente force de liaison entre la membrane polarisante et le film protecteur transparent malgré l'absence d'utilisation d'une couche adhésive sensible à la pression ou d'une couche adhésive.
PCT/JP2023/010809 2022-03-30 2023-03-20 Procédé de fabrication de film polarisant WO2023189797A1 (fr)

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JP2022-055473 2022-03-30

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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08278407A (ja) * 1995-04-05 1996-10-22 Olympus Optical Co Ltd ビームスプリッター及び光ピックアップ用ビームスプ リッター
JP2003084130A (ja) * 2001-09-12 2003-03-19 Shin Etsu Chem Co Ltd 光学デバイスの製造方法及び光学デバイス
JP2003270437A (ja) * 2002-03-15 2003-09-25 Shin Etsu Chem Co Ltd 光学デバイスの製造方法及び光学デバイス
JP2010170122A (ja) * 2008-12-23 2010-08-05 Sumitomo Chemical Co Ltd 光学フィルム及びそれを含む液晶表示装置
KR20140134148A (ko) * 2013-05-13 2014-11-21 동우 화인켐 주식회사 복합 편광판 일체형 윈도우 필름
JP2017198939A (ja) * 2016-04-28 2017-11-02 エルジー ディスプレイ カンパニー リミテッド 電気光学パネル
JP2021073499A (ja) * 2018-02-28 2021-05-13 日東電工株式会社 動力走行車両用の偏光フィルム積層体、及び、該偏光フィルム積層体が使用される光学表示パネル

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08278407A (ja) * 1995-04-05 1996-10-22 Olympus Optical Co Ltd ビームスプリッター及び光ピックアップ用ビームスプ リッター
JP2003084130A (ja) * 2001-09-12 2003-03-19 Shin Etsu Chem Co Ltd 光学デバイスの製造方法及び光学デバイス
JP2003270437A (ja) * 2002-03-15 2003-09-25 Shin Etsu Chem Co Ltd 光学デバイスの製造方法及び光学デバイス
JP2010170122A (ja) * 2008-12-23 2010-08-05 Sumitomo Chemical Co Ltd 光学フィルム及びそれを含む液晶表示装置
KR20140134148A (ko) * 2013-05-13 2014-11-21 동우 화인켐 주식회사 복합 편광판 일체형 윈도우 필름
JP2017198939A (ja) * 2016-04-28 2017-11-02 エルジー ディスプレイ カンパニー リミテッド 電気光学パネル
JP2021073499A (ja) * 2018-02-28 2021-05-13 日東電工株式会社 動力走行車両用の偏光フィルム積層体、及び、該偏光フィルム積層体が使用される光学表示パネル

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