WO2012086592A1 - Polyester film for optical use - Google Patents

Polyester film for optical use Download PDF

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Publication number
WO2012086592A1
WO2012086592A1 PCT/JP2011/079374 JP2011079374W WO2012086592A1 WO 2012086592 A1 WO2012086592 A1 WO 2012086592A1 JP 2011079374 W JP2011079374 W JP 2011079374W WO 2012086592 A1 WO2012086592 A1 WO 2012086592A1
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Prior art keywords
film
polyester
transparency
particles
polyester film
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PCT/JP2011/079374
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French (fr)
Japanese (ja)
Inventor
加藤優佳
尼子勝也
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三菱樹脂株式会社
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Publication of WO2012086592A1 publication Critical patent/WO2012086592A1/en

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/18—Manufacture of films or sheets
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
    • G02B1/04—Optical elements characterised by the material of which they are made; Optical coatings for optical elements made of organic materials, e.g. plastics
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
    • G02B1/10—Optical coatings produced by application to, or surface treatment of, optical elements
    • G02B1/14—Protective coatings, e.g. hard coatings
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2367/00—Characterised by the use of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Derivatives of such polymers
    • G02B1/105—

Definitions

  • the present invention relates to an optical polyester film, and more particularly, it has excellent clear feeling when used as a base film for a transparent conductive film of a touch panel display member, prevents optical defects due to adhesion of dust and the like, and is scratched.
  • the present invention relates to an optical polyester film excellent in prevention, workability, and productivity.
  • Biaxially stretched polyester films represented by polyethylene terephthalate and polyethylene naphthalate have excellent mechanical strength, dimensional stability, flatness, heat resistance, chemical resistance, optical properties, etc., and cost performance. It is also used for various purposes.
  • the touch panel display member is provided with a hard-coated film on both sides or one side and a transparent conductive film (ITO film) on the other side in terms of durability at pen input and good writing due to the cushioning effect of the adhesive.
  • ITO film transparent conductive film
  • an ITO film used as a transparent conductive film is usually crystallized by heat treatment at 150 ° C. for about 30 minutes (Patent Document 1). . Further, when this ITO film is crystallized in the form shown in Patent Document 2, a low molecular weight substance (oligomer) of PET is deposited on the back surface of the ITO film, that is, on the adhesive side, resulting in an optical defect (bright spot). It becomes a problem.
  • haze measurement There is a haze measurement as one of the methods for evaluating the transparency of a film.
  • haze There are two types of haze: surface haze and internal haze.
  • Surface haze is a physical property that evaluates scattering caused by the surface structure (rough surface, etc.) of the film.
  • Internal haze is scattering caused by the internal structure (void, etc.) of the film. It is a physical property evaluated. Therefore, according to the internal haze, it is possible to predict the haze value when the film is laminated with another material (hard coat or adhesive material, etc.) and laminated (excluding scattering caused by the surface structure). it can.
  • the measurement of the internal haze of a polyester film can be easily performed by using ethanol as a rough surface compensation solvent.
  • Patent Document 3 Even a highly transparent polyester film having an internal haze of 0.6% or less shown in Patent Document 3 has a particle feeling confirmed by visual inspection. In other words, the transparency of the film cannot be sufficiently evaluated with the internal haze value, and the demand for a film with excellent transparency has not yet been met.
  • the present invention has been made in view of the above circumstances, and its solution is an optical that is excellent in transparency and sharpness when used as a display member, hardly scratched, and has excellent workability and productivity. It is to provide a polyester film.
  • the first gist of the present invention resides in an optical polyester film characterized in that the transparency is 83.5% or more and the roughness (Ra) of one film surface is 9.0 nm or more.
  • the second gist of the present invention resides in an optical polyester film characterized in that the internal transparency is 96.5% or more and the roughness (Ra) of one film surface is 9.0 nm or more.
  • polyester film of the present invention it is possible to provide an optical polyester film that is excellent in visibility as a display member such as a display, has few scratches on the film surface, and has excellent workability.
  • the polyester film referred to in the present invention is a film that is melt-extruded from an extrusion die, and is subjected to stretching and heat treatment as necessary after cooling a molten polyester sheet extruded by a so-called extrusion method.
  • the polyester constituting the film of the present invention is obtained by polycondensation of an aromatic dicarboxylic acid and an aliphatic glycol.
  • aromatic dicarboxylic acid include terephthalic acid and 2,6-naphthalenedicarboxylic acid
  • aliphatic glycol include ethylene glycol, diethylene glycol, and 1,4-cyclohexanedimethanol.
  • Representative polyesters include polyethylene terephthalate (PET), polyethylene-2,6-naphthalenedicarboxylate (PEN), and the like.
  • PET polyethylene terephthalate
  • PEN polyethylene-2,6-naphthalenedicarboxylate
  • the polyester used may be a homopolyester or a copolyester.
  • a copolyester it may be a copolymer containing 30 mol% or less of the third component.
  • the dicarboxylic acid component of such a copolyester include isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, and oxycarboxylic acid (eg, P-oxybenzoic acid). 1 type or 2 types or more chosen from are mentioned.
  • One glycol component may be one or more selected from ethylene glycol, diethylene glycol, propylene glycol, butanediol, 1,4-cyclohexanedimethanol, neopentyl glycol, and the like.
  • a weathering agent a light-proofing agent, an antistatic agent, a lubricant, a light-shielding agent, an antioxidant, a fluorescent whitening agent, a matting agent, and a heat-stabilizing agent as long as the gist of the invention is not impaired
  • Examples of the particles to be blended in the film include silicon oxide, alumina, calcium carbonate, kaolin, titanium oxide, organic particles, and crosslinked polymer fine powder as described in JP-B-59-5216. These particles may be used alone or in combination of two or more components.
  • the blending amount of these particles is usually 5 to 90 ppm or less, preferably 20 to 80 ppm with respect to the polyester constituting the film.
  • the content of the particles is small, the film surface cannot be appropriately roughened, and in the film production process, there is a tendency that the surface is easily scratched or the winding properties are inferior.
  • the content of the particles is 90 ppm or more, the degree of roughening of the film surface becomes too large, and transparency may be impaired.
  • a method of blending particles only in the surface layer is preferably employed.
  • the surface layer in this case is at least one of the front and back layers, and of course, particles can be blended in both the front and back layers.
  • the blending amount of the particles in the case of such a laminated film is preferably in the range of 0.01 to 2% by weight, more preferably 0.02 to 1% by weight with respect to the polyester constituting the surface layer.
  • a sharp particle size distribution is preferably used.
  • those having a particle size distribution value of 1.0 to 2.0, which is an index representing the sharpness of the particle size distribution are preferable.
  • the particle size distribution value is the particle size distribution value d25 / d75 (d25 and d75 are calculated by calculating the accumulated accumulation of the particle group from the large particle side, and the particle size ( ⁇ m corresponding to 25% and 75% of the total volume, respectively) Is a value defined by When the particle size distribution value exceeds 2.0, transparency may be insufficient.
  • the present invention includes two inventions that define the transparency and internal transparency of the film.
  • the meanings of transparency and internal transparency are the same as those described above for haze and internal haze.
  • the transparency of the film in the measuring method mentioned later needs to be 83.5% or more, and it is preferable that it is 84.0% or more. When the transparency of the film is less than 83.5%, the transparency of the film is lowered.
  • the internal transparency of the film in the measurement method described later needs to be 96.5% or more, and preferably 97.0% or more. When the transparency of the film is less than 96.5%, the transparency of the film is lowered.
  • the film production line It can be achieved by appropriately combining various conditions such as smoothing of the roll used in the above.
  • the surface roughness (Ra) of the film is usually 9.0 nm or more, more preferably 12.0 nm or more.
  • Ra of the film is less than 9.0 nm, the film surface becomes extremely flat, and the winding characteristics in the film manufacturing process are inferior.
  • Ra of the film exceeds 22.0 nm, the planarity of the surface may be impaired, and the film may become whitish. Therefore, the upper limit of Ra is preferably 22.0 nm.
  • the method of blending the particles with the polyester is not particularly limited, and a known method can be adopted.
  • it can be added at any stage for producing the polyester, but it is preferably added as a slurry dispersed in ethylene glycol or the like at the stage of esterification or before the start of the polycondensation reaction after the transesterification reaction.
  • the condensation reaction may proceed.
  • the polyester may be chipped after melt polymerization, and further subjected to solid phase polymerization as necessary under heating under reduced pressure or in an inert gas stream such as nitrogen.
  • the intrinsic viscosity of the obtained polyester is preferably 0.40 dL / g or more, more preferably 0.40 to 0.90 dL / g.
  • the total thickness of the film of the present invention is not particularly limited as long as it can be formed as a film, but is usually 4 to 300 ⁇ m, preferably 25 to 188 ⁇ m.
  • a polyester chip obtained as described above and dried by a known method is supplied to a melt-extrusion apparatus and heated to a temperature equal to or higher than the melting point of each polymer to melt.
  • the molten polymer is extruded from the die, and rapidly cooled and solidified on the rotary cooling drum so as to have a temperature equal to or lower than the glass transition temperature to obtain a substantially amorphous unoriented sheet.
  • an electrostatic application adhesion method and / or a liquid application adhesion method is preferably employed.
  • the sheet thus obtained is stretched biaxially to form a film.
  • the unstretched sheet is preferably stretched 2 to 6 times in the machine direction at 70 to 145 ° C. to form a uniaxially stretched film, and then 2 to 90 to 160 ° C. in the transverse direction.
  • the film is preferably stretched up to 6 times and heat-treated at 150-240 ° C. for 1-600 seconds. Further, at this time, it is preferable to relax by 0.1 to 20% in the longitudinal direction and / or the transverse direction in the maximum temperature zone of the heat treatment and / or the cooling zone at the heat treatment outlet. Further, it is possible to add re-longitudinal stretching and re-lateral stretching as necessary. Further, it is possible to simultaneously biaxially stretch the unstretched sheet so that the area magnification is 10 to 40 times.
  • the polyester film of the present invention can be subjected to so-called in-line coating in which the film surface is treated during the stretching step as long as the effects of the present invention are not impaired.
  • in-line coating in which the film surface is treated during the stretching step as long as the effects of the present invention are not impaired.
  • a coating treatment with an aqueous solution, an aqueous emulsion, an aqueous slurry, or the like can be performed.
  • Various coatings may be performed by offline coating after film production. Such a coat may be either single-sided or double-sided.
  • the coating material may be either water-based or solvent-based for offline coating, but is preferably water-based for in-line coating.
  • Average particle diameter (d50) The average particle size d50 was defined as the particle size having an integrated volume fraction of 50% in an equivalent spherical distribution measured using a centrifugal sedimentation type particle size distribution analyzer (SA-CP3 type) manufactured by Shimadzu Corporation.
  • Measurement of transparency of film Measurements were made in accordance with ASTM D1746 using a transparency measuring instrument (TM-1D 2-digit type after decimal point: light source wavelength 546 ⁇ 5 nm) manufactured by Murakami Color Research Laboratory.
  • Measurement of film haze Measurement was performed according to JIS K7136 using a haze meter (HZ-2) manufactured by Suga Test Instruments.
  • Measurement of internal haze of film Measurement was performed using a haze meter (HZ-2) manufactured by Suga Test Instruments. The measurement was performed using ethanol as a rough surface compensation solvent. That is, it measured by setting a film in a glass cell and immersing in ethanol.
  • HZ-2 haze meter
  • Ra film surface roughness
  • Evaluation of scratch resistance The number of scratches on the produced film surface was counted, and the difficulty of scratching was evaluated. Evaluation was performed using an A4 size film. ⁇ Criteria> (It is hard to be scratched) ⁇ > ⁇ > ⁇ (It is easy to be scratched) ⁇ : Scratch occurrence frequency is 3 or less ⁇ : Scratch occurrence frequency is 5 or less ⁇ : Scratch occurrence frequency is 5 or more In the above criteria, ⁇ or more is a level that can be used without any problem in actual use.
  • Examples 1 to 4 and Comparative Examples 1 to 7 ⁇ Manufacture of polyester (A)> Starting from 100% by weight of dimethyl terephthalate and 60% by weight of ethylene glycol, magnesium acetate tetrahydrate is added as a catalyst to the reactor, the reaction start temperature is 150 ° C., and the reaction temperature is gradually increased as methanol is distilled off. The temperature was raised to 230 ° C. after 3 hours. After 4 hours, the transesterification reaction was substantially terminated. Ethyl acid phosphate was added to the reaction mixture, which was then transferred to a polycondensation tank, and 0.04 part of antimony trioxide was added to carry out a polycondensation reaction for 4 hours.
  • the temperature was gradually raised from 230 ° C. to 280 ° C.
  • the pressure was gradually reduced from normal pressure, and finally 0.3 mmHg.
  • the reaction was stopped at a time corresponding to an intrinsic viscosity of 0.64 dL / g due to a change in the stirring power of the reaction vessel, and the polymer was discharged under nitrogen pressure to obtain a polyester chip (A).
  • the intrinsic viscosity of this polyester was 0.64 dL / g.
  • polyester (B1 to B4) ⁇ Production of polyester (B1 to B4)>
  • the content of ethylene glycol slurry of divinylbenzene / methyl methacrylate copolymer crosslinked particles having different average particle diameters is 0.5% by weight with respect to polyester.
  • Polyesters (B1 to B4) were obtained using the same method as the production method of the polyester (A) except that it was added as described above.
  • the production method of divinylbenzene / methyl methacrylate copolymer crosslinked particles is as follows.
  • a homogeneous solution of 100 parts of methyl methacrylate, 25 parts of divinylbenzene, 22 parts of ethylvinylbenzene, 1 part of benzoyl peroxide and 100 parts of toluene is dispersed in 700 parts of water, and then stirred at 80 ° C. for 6 hours in a nitrogen atmosphere. Polymerization was carried out while heating. The average particle diameter of the obtained crosslinked polymer granules having ester groups was about 0.1 mm. The produced polymer was washed with demineralized water and extracted twice with 500 parts of toluene to remove a small amount of unreacted monomer linear polymer.
  • the crosslinked polymer particles are pulverized with an attritor and a sand grinder to obtain divinylbenzene / methyl methacrylate copolymer having average particle diameters of 0.8, 1.4, 2.3, and 4.4 ⁇ m having different particle diameters.
  • Polymerized crosslinked particles were obtained.
  • B1 is a polyester chip containing particles having a particle diameter of 0.8 ⁇ m
  • B2 is a chip containing particles of 1.4 ⁇ m
  • B3 is a chip containing particles of 2.3 ⁇ m
  • B4 is a chip containing particles of 4.4 ⁇ m. It was.
  • the obtained polyester chips (B1 to B4) all had an intrinsic viscosity of 0.62 dL / g.
  • polyester (C) ⁇ Manufacture of polyester (C)>
  • the same method as the method for producing polyester (B), except that the additive particles are silica particles having an average particle diameter of 2.7 ⁇ m and the content with respect to the polyester is 0.3% by weight. was used to obtain a polyester (D).
  • the obtained polyester (D) had an intrinsic viscosity of 0.61 dL / g.
  • polyester (D) ⁇ Manufacture of polyester (D)>
  • the additive particles are the same as the production method of the polyester (B) except that silica particles having an average particle diameter of 3.2 ⁇ m and the content with respect to the polyester are 0.6% by weight.
  • Polyester (D) was obtained using the method. The average particle size was determined by a laser method. The obtained polyester (D) had an intrinsic viscosity of 0.62 dL / g.
  • a mixed raw material obtained by mixing the polyester (A) chip and the polyester (B), (C), and (D) chips in the proportions shown in Table 1 is used as a raw material for the outermost layer (surface layer) and the intermediate layer.
  • Each was supplied to an extruder, melt-extruded at 280 ° C., and then cooled and solidified on a cooling roll having a surface temperature set to 30 ° C. using an electrostatic application adhesion method to obtain an unstretched sheet.
  • the film was stretched 3.5 times in the longitudinal direction at 85 ° C., and then subjected to a preheating step in the tenter and 4.3 times transverse stretching at 105 ° C., followed by heat treatment at 235 ° C. for 10 seconds, Each 250 mm polyester film was obtained.
  • the total thickness of the obtained film was 50 ⁇ m, and the thickness of each layer was 2.5 ⁇ m / 45 ⁇ m / 2.5 ⁇ m.
  • the optical polyester film of the present invention can be suitably used, for example, as a base film for a transparent conductive film of a touch panel display member.

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  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Health & Medical Sciences (AREA)
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  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
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Abstract

Provided is a useful polyester film for optical use, which has excellent clarity when used as a base film for a transparent conductive film, for example, a base film for a display member such as a touch panel. The polyester film for optical use prevents optical defects by inhibiting adhesion of dust and the like, and exhibits excellent transparency and definition. The polyester film for optical use has a surface that is not susceptible to scratches, while having excellent handleability and productivity. The polyester film for optical use has a transparency degree of 83.5% or more (or an internal transparency degree of 96.5% or more), and one surface of the film has a roughness (Ra) of 9.0 nm or more.

Description

光学用ポリエステルフィルムOptical polyester film
　本発明は、光学用ポリエステルフィルムに関し、詳しくは、タッチパネル表示部材の透明導電性フィルム用ベースフィルムとして用いられたときのクリア感に優れ、埃等の付着防止による光学的欠陥を防止し、キズつき防止、作業性、生産性に優れた光学用ポリエステルフィルムに関するものである。 The present invention relates to an optical polyester film, and more particularly, it has excellent clear feeling when used as a base film for a transparent conductive film of a touch panel display member, prevents optical defects due to adhesion of dust and the like, and is scratched. The present invention relates to an optical polyester film excellent in prevention, workability, and productivity.
　ポリエチレンテレフタレートやポリエチレンナフタレートに代表される二軸延伸ポリエステルフィルムは、機械的強度、寸法安定性、平坦性、耐熱性、耐薬品性、光学特性等に優れた特性を有し、また、コストパフォーマンスにも優れるため、各種用途に使用されている。 Biaxially stretched polyester films represented by polyethylene terephthalate and polyethylene naphthalate have excellent mechanical strength, dimensional stability, flatness, heat resistance, chemical resistance, optical properties, etc., and cost performance. It is also used for various purposes.
　最近では、タッチパネル式の表示装置に用いられる透明導電性フィルムのベースフィルムや液晶表示装置に用いられるプリズムシート用のベースフィルムやブラウン管、ＬＣＤ、ＰＤＰ等の、いわゆるフラットディスプレイの光学用フィルムとして広く用いられているが、ポリエステルフィルムはキズが付きやすいため、外観や光学特性が損なわれやすいという欠点がある。 Recently, it is widely used as an optical film for so-called flat displays such as base films for transparent conductive films used for touch panel display devices, prism film base films used for liquid crystal display devices, cathode ray tubes, LCDs, PDPs, etc. However, since the polyester film is easily scratched, there is a drawback that the appearance and optical characteristics are easily impaired.
　特に、最近需要の増えているタッチパネル機能付きの携帯情報端末や携帯電話、携帯ゲーム機においては、表示部を至近距離で見ることから、表示部ベース材として、キズや異物等の光学欠点の少ないフィルムが求められている。また、ＴＶや動画再生等の高機能化が進むにつれ、表示部材ベースフィルムとしての透明性および鮮明性に対する要求も厳しくなっている。 In particular, in portable information terminals, mobile phones, and portable game machines with a touch panel function, which has recently been increasing in demand, since the display unit is viewed at a close range, the display unit base material has few optical defects such as scratches and foreign matter. There is a need for films. In addition, as functions such as TV and moving image playback are advanced, demands for transparency and clarity as a display member base film are becoming stricter.
　タッチパネル表示部材としては、ペン入力時の耐久性が良好かつ粘着剤のクッション効果による書き味が良好な点で、両面あるいは片面にハードコート処理したフィルムと片面に透明導電膜（ＩＴＯ膜）を設けたフィルムの他面とを粘着層を介して接着積層したものが広く用いられている。 The touch panel display member is provided with a hard-coated film on both sides or one side and a transparent conductive film (ITO film) on the other side in terms of durability at pen input and good writing due to the cushioning effect of the adhesive. A film obtained by adhering and laminating the other side of the film with an adhesive layer is widely used.
　透明導電膜として用いられるＩＴＯ膜は、筆記耐久性、寸法安定性の向上のため成膜後、１５０℃、３０分程度の熱処理で結晶化処理することが通常行われている（特許文献１）。また、特許文献２に示される形態でこのＩＴＯ膜の結晶化処理を行うと、ＩＴＯ膜の裏面、すなわち粘着剤側にＰＥＴの低分子量物（オリゴマー）が析出し、光学欠点（輝点）となり問題となる。 In order to improve writing durability and dimensional stability, an ITO film used as a transparent conductive film is usually crystallized by heat treatment at 150 ° C. for about 30 minutes (Patent Document 1). . Further, when this ITO film is crystallized in the form shown in Patent Document 2, a low molecular weight substance (oligomer) of PET is deposited on the back surface of the ITO film, that is, on the adhesive side, resulting in an optical defect (bright spot). It becomes a problem.
　透明導電性フィルムのベースフィルムとして透明性および鮮明性を改良するには、フィルム中に含有する滑剤粒子を減らすことで達成できるが、滑剤粒子を減らしすぎると製膜時や加工時の巻き作業性の低下や、フィルム表面へのキズ入りが多くなり、外観特性を損ない問題となる。 To improve transparency and sharpness as a base film of transparent conductive film, it can be achieved by reducing the lubricant particles contained in the film, but if the lubricant particles are reduced too much, the winding workability during film formation and processing And the appearance of scratches on the film surface increase, resulting in a problem that the appearance characteristics are impaired.
　フィルムの透明性の評価方法の一つとしてヘーズ測定がある。ヘーズには表面ヘーズと内部ヘーズとがあり、表面ヘーズはフィルムの表面構造（粗面など）に起因する散乱を評価した物性であり、内部ヘーズはフィルムの内部構造（ボイドなど）に起因する散乱を評価した物性である。従って、内部ヘーズによればフィルムと他の材料（ハードコート又は粘着材等）とを張り合わせて積層した状態（表面構造に起因する散乱を除いた状態）にしたときのヘーズ値を予測することができる。そして、ポリエステルフィルムの内部ヘーズの測定は、粗面補償溶媒として例えばエタノールを用いることにより容易に行うことができる。 There is a haze measurement as one of the methods for evaluating the transparency of a film. There are two types of haze: surface haze and internal haze. Surface haze is a physical property that evaluates scattering caused by the surface structure (rough surface, etc.) of the film. Internal haze is scattering caused by the internal structure (void, etc.) of the film. It is a physical property evaluated. Therefore, according to the internal haze, it is possible to predict the haze value when the film is laminated with another material (hard coat or adhesive material, etc.) and laminated (excluding scattering caused by the surface structure). it can. And the measurement of the internal haze of a polyester film can be easily performed by using ethanol as a rough surface compensation solvent.
　ところが、特許文献３に示される内部ヘーズ０．６％以下の高透明ポリエステルフィルムであっても目視検査では粒子感が確認される。つまり、内部ヘーズ値ではフィルムの透明性を十分に評価することできず、透明性に優れたフィルムの要求に応えることがまだできていない現状にある。 However, even a highly transparent polyester film having an internal haze of 0.6% or less shown in Patent Document 3 has a particle feeling confirmed by visual inspection. In other words, the transparency of the film cannot be sufficiently evaluated with the internal haze value, and the demand for a film with excellent transparency has not yet been met.
特開２００３－４８２８９号公報JP 2003-48289 A 特開平８－１４８０３６号公報JP-A-8-148036 特開平２００９－２１４３６０号公報JP 2009-214360 A
　本発明は、上記実情に鑑みなされたものであって、その解決課題は、表示部材として用いられたときの透明性および鮮明性に優れ、キズがつきにくく、作業性、生産性に優れた光学用ポリエステルフィルムを提供することにある。 The present invention has been made in view of the above circumstances, and its solution is an optical that is excellent in transparency and sharpness when used as a display member, hardly scratched, and has excellent workability and productivity. It is to provide a polyester film.
　本発明者らは、上記実情に鑑み鋭意検討を重ねた結果、特定構成のポリエステルフィルムによれば上記課題を容易に解決できることを見いだし、本発明を完成するに至った。 As a result of intensive studies in view of the above circumstances, the present inventors have found that the above problem can be easily solved by a polyester film having a specific configuration, and have completed the present invention.
　すなわち、本発明の第１の要旨は、透明度が８３．５％以上であり、一方のフィルム表面の粗さ（Ｒａ）が９．０ｎｍ以上であることを特徴とする光学用ポリエステルフィルムに存し、本発明の第２の要旨は、内部透明度が９６．５％以上であり、一方のフィルム表面の粗さ（Ｒａ）が９．０ｎｍ以上であることを特徴とする光学用ポリエステルフィルムに存する。 That is, the first gist of the present invention resides in an optical polyester film characterized in that the transparency is 83.5% or more and the roughness (Ra) of one film surface is 9.0 nm or more. The second gist of the present invention resides in an optical polyester film characterized in that the internal transparency is 96.5% or more and the roughness (Ra) of one film surface is 9.0 nm or more.
　本発明のポリエステルフィルムによれば、ディスプレイ等の表示部材としての視認性に優れ、かつフィルム表面へのキズ入りが少なく、作業性に優れた光学用ポリエステルフィルムを提供することができる。 According to the polyester film of the present invention, it is possible to provide an optical polyester film that is excellent in visibility as a display member such as a display, has few scratches on the film surface, and has excellent workability.
　本発明で言うポリエステルフィルムとは、押出口金から溶融押出される、いわゆる押出法により押出した溶融ポリエステルシートを冷却した後、必要に応じ、延伸、熱処理を施したフィルムである。 The polyester film referred to in the present invention is a film that is melt-extruded from an extrusion die, and is subjected to stretching and heat treatment as necessary after cooling a molten polyester sheet extruded by a so-called extrusion method.
　本発明のフィルムを構成するポリエステルとは、芳香族ジカルボン酸と脂肪族グリコールとを重縮合させて得られるものである。芳香族ジカルボン酸としては、テレフタル酸、２，６－ナフタレンジカルボン酸などが挙げられ、脂肪族グリコールとしては、エチレングリコール、ジエチレングリコール、１，４－シクロヘキサンジメタノール等が挙げられる。代表的なポリエステルとしては、ポリエチレンテレフタレート（ＰＥＴ）、ポリエチレン－２，６－ナフタレンジカルボキシレート（ＰＥＮ）等が例示される。また、用いるポリエステルは、ホモポリエステルであっても共重合ポリエステルであってもよい。共重合ポリエステルの場合は、３０モル％以下の第三成分を含有した共重合体であればよい。
　このような共重合ポリエステルのジカルボン酸成分としては、イソフタル酸、フタル酸、テレフタル酸、２，６－ナフタレンジカルボン酸、アジピン酸、セバシン酸およびオキシカルボン酸（例えば、Ｐ－オキシ安息香酸など）等から選ばれる一種または二種以上が挙げられる。一方のグリコール成分としては、エチレングリコール、ジエチレングリコール、プロピレングリコール、ブタンジオール、１，４－シクロヘキサンジメタノール、ネオペンチルグリコール等から選ばれる一種または二種以上が挙げられる。 The polyester constituting the film of the present invention is obtained by polycondensation of an aromatic dicarboxylic acid and an aliphatic glycol. Examples of the aromatic dicarboxylic acid include terephthalic acid and 2,6-naphthalenedicarboxylic acid, and examples of the aliphatic glycol include ethylene glycol, diethylene glycol, and 1,4-cyclohexanedimethanol. Representative polyesters include polyethylene terephthalate (PET), polyethylene-2,6-naphthalenedicarboxylate (PEN), and the like. The polyester used may be a homopolyester or a copolyester. In the case of a copolyester, it may be a copolymer containing 30 mol% or less of the third component.
Examples of the dicarboxylic acid component of such a copolyester include isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, and oxycarboxylic acid (eg, P-oxybenzoic acid). 1 type or 2 types or more chosen from are mentioned. One glycol component may be one or more selected from ethylene glycol, diethylene glycol, propylene glycol, butanediol, 1,4-cyclohexanedimethanol, neopentyl glycol, and the like.
　本発明で得られるポリエステルには、本発明の要旨を損なわない範囲で、耐候剤、耐光剤、帯電防止剤、潤滑剤、遮光剤、抗酸化剤、蛍光増白剤、マット化剤、熱安定剤、および染料、顔料などの着色剤などを配合してもよい。 In the polyester obtained by the present invention, a weathering agent, a light-proofing agent, an antistatic agent, a lubricant, a light-shielding agent, an antioxidant, a fluorescent whitening agent, a matting agent, and a heat-stabilizing agent as long as the gist of the invention is not impaired You may mix | blend an agent and coloring agents, such as dye and a pigment.
　フィルムに配合する粒子としては、酸化ケイ素、アルミナ、炭酸カルシウム、カオリン、酸化チタン、有機粒子および特公昭５９－５２１６号公報に記載されているような架橋高分子微粉体等を挙げることができる。これらの粒子は、単独あるいは２成分以上を同時に使用してもよい。これら粒子の配合量は、フィルムを構成するポリエステルに対し、通常５～９０ｐｐｍ以下、好ましくは２０～８０ｐｐｍの範囲である。粒子の含有量が少ない場合には、フィルム表面を適度な粗面にすることができず、フィルム製造工程において、表面のキズが発生しやすかったり、巻き特性が劣ったりする傾向がある。また、粒子の含有量が９０ｐｐｍ以上の場合には、フィルム表面の粗面化の度合いが大きくなりすぎて透明性が損なわれることがある。 Examples of the particles to be blended in the film include silicon oxide, alumina, calcium carbonate, kaolin, titanium oxide, organic particles, and crosslinked polymer fine powder as described in JP-B-59-5216. These particles may be used alone or in combination of two or more components. The blending amount of these particles is usually 5 to 90 ppm or less, preferably 20 to 80 ppm with respect to the polyester constituting the film. When the content of the particles is small, the film surface cannot be appropriately roughened, and in the film production process, there is a tendency that the surface is easily scratched or the winding properties are inferior. Moreover, when the content of the particles is 90 ppm or more, the degree of roughening of the film surface becomes too large, and transparency may be impaired.
　ポリエステルフィルム中に配合する粒子の平均粒径としては、特に限定されるものではないが、通常０．０２～４．０μｍ、好ましくは０．６～２．５μｍの範囲である。平均粒径が０．０２μｍ未満の粒子を用いた場合には、十分な易滑性の付与が出来ないため、フィルム製造工程における巻き特性が劣る傾向がある。また、平均粒径が４．０μｍを超える場合には、フィルム表面の粗面化の度合いが大きくなりすぎてフィルムがヘージーとなる場合がある。 The average particle size of the particles blended in the polyester film is not particularly limited, but is usually in the range of 0.02 to 4.0 μm, preferably 0.6 to 2.5 μm. When particles having an average particle size of less than 0.02 μm are used, sufficient slipperiness cannot be imparted, so that the winding characteristics in the film production process tend to be inferior. On the other hand, when the average particle diameter exceeds 4.0 μm, the degree of roughening of the film surface becomes too large and the film may become hazy.
　一方、フィルムの透明性を向上させるため、２層以上の積層フィルムとした場合、表層のみに粒子を配合する方法も好ましく採用される。この場合の表層とは、少なくとも表裏どちらか１層であり、もちろん表裏両層に粒子を配合することもできる。かかる積層フィルムとした場合の粒子の配合量は、表層を構成するポリエステルに対し、好ましくは０．０１～２重量％、さらに好ましくは０．０２～１重量％の範囲である。 On the other hand, in order to improve the transparency of the film, when a laminated film having two or more layers is used, a method of blending particles only in the surface layer is preferably employed. The surface layer in this case is at least one of the front and back layers, and of course, particles can be blended in both the front and back layers. The blending amount of the particles in the case of such a laminated film is preferably in the range of 0.01 to 2% by weight, more preferably 0.02 to 1% by weight with respect to the polyester constituting the surface layer.
　また、用いられる粒子の粒度分布はシャープな物が好ましい。具体的には、粒度分布のシャープさを表す指標である粒度分布値が１．０～２．０のものが好ましい。なお、ここで粒度分布値とは、粒度分布値ｄ２５／ｄ７５（ｄ２５、ｄ７５は粒子群の積算堆積を大粒子側から計算し、それぞれ総体積の２５％、７５％に相当する粒径（μｍ）を示す）により定義される値である。粒度分布値が２．０を超える場合、透明性が不十分になる可能性がある。 In addition, a sharp particle size distribution is preferably used. Specifically, those having a particle size distribution value of 1.0 to 2.0, which is an index representing the sharpness of the particle size distribution, are preferable. Here, the particle size distribution value is the particle size distribution value d25 / d75 (d25 and d75 are calculated by calculating the accumulated accumulation of the particle group from the large particle side, and the particle size (μm corresponding to 25% and 75% of the total volume, respectively) Is a value defined by When the particle size distribution value exceeds 2.0, transparency may be insufficient.
　本発明は、フィルムの透明度と内部透明度を規定した２つの発明を包含するが、透明度と内部透明度の意義は、ヘーズと内部ヘーズついての前述の意義と同様である。
　第１の要旨に係る本発明において、後述する測定法におけるフィルムの透明度は８３．５％以上であることが必要であり、８４．０％以上であることが好ましい。フィルムの透明度が８３．５％を下回る場合、フィルムの透明感が低下する。
　第２の要旨に係る本発明において、後述する測定法におけるフィルムの内部透明度は９６．５％以上であることが必要であり、９７．０％以上であることが好ましい。フィルムの透明度が９６．５％を下回る場合、フィルムの透明感が低下する。 The present invention includes two inventions that define the transparency and internal transparency of the film. The meanings of transparency and internal transparency are the same as those described above for haze and internal haze.
In this invention which concerns on a 1st summary, the transparency of the film in the measuring method mentioned later needs to be 83.5% or more, and it is preferable that it is 84.0% or more. When the transparency of the film is less than 83.5%, the transparency of the film is lowered.
In the present invention according to the second aspect, the internal transparency of the film in the measurement method described later needs to be 96.5% or more, and preferably 97.0% or more. When the transparency of the film is less than 96.5%, the transparency of the film is lowered.
　フィルムの透明度または内部透明度を上記範囲とするためには、例えば、用いる粒子の種類、粒径、添加量、製造ラインにおけるフィルターの強化、フィルム製造条件（フィルム延伸温度、延伸倍率）、フィルム製造ラインで使用するロールの平滑化等、種々の条件を適宜組み合わせることによって達成することができる。 In order to set the transparency or internal transparency of the film within the above range, for example, the type of particles used, the particle size, the amount added, the strengthening of the filter in the production line, the film production conditions (film stretching temperature, draw ratio), the film production line It can be achieved by appropriately combining various conditions such as smoothing of the roll used in the above.
　また、フィルムの表面粗さ（Ｒａ）は、通常９．０ｎｍ以上、より好ましくは１２．０ｎｍ以上である。フィルムのＲａが９．０ｎｍを下回る場合、フィルム表面が極端に平坦となり、フィルム製造工程における巻き特性が劣る。また、フィルムのＲａが２２．０ｎｍを超える場合、表面の平面性が損なわれることがあり、フィルムが白っぽくなる恐れがあるので、Ｒａの上限は２２．０ｎｍとすることが好ましい。 Further, the surface roughness (Ra) of the film is usually 9.0 nm or more, more preferably 12.0 nm or more. When Ra of the film is less than 9.0 nm, the film surface becomes extremely flat, and the winding characteristics in the film manufacturing process are inferior. Moreover, when Ra of the film exceeds 22.0 nm, the planarity of the surface may be impaired, and the film may become whitish. Therefore, the upper limit of Ra is preferably 22.0 nm.
　本発明において、ポリエステルに粒子を配合する方法としては、特に限定されるものではなく、公知の方法を採用し得る。例えば、ポリエステルを製造する任意の段階において添加することができるが、好ましくはエステル化の段階、もしくはエステル交換反応終了後重縮合反応開始前の段階でエチレングリコール等に分散させたスラリーとして添加し重縮合反応を進めてもよい。またベント付き混練押出機を用い、エチレングリコールまたは水などに分散させた粒子のスラリーとポリエステル原料とをブレンドする方法、または、混練押出機を用い、乾燥させた粒子とポリエステル原料とをブレンドする方法などによって行われる。 In the present invention, the method of blending the particles with the polyester is not particularly limited, and a known method can be adopted. For example, it can be added at any stage for producing the polyester, but it is preferably added as a slurry dispersed in ethylene glycol or the like at the stage of esterification or before the start of the polycondensation reaction after the transesterification reaction. The condensation reaction may proceed. Also, a method of blending a slurry of particles dispersed in ethylene glycol or water with a vented kneading extruder and a polyester raw material, or a method of blending dried particles and a polyester raw material using a kneading extruder Etc.
　なおポリエステルは、溶融重合後これをチップ化し、加熱減圧下または窒素等不活性気流中に必要に応じてさらに固相重合を施してもよい。得られるポリエステルの固有粘度は０．４０ｄＬ／ｇ以上であることが好ましく、０．４０～０．９０ｄＬ／ｇであることがさらに好ましい。 The polyester may be chipped after melt polymerization, and further subjected to solid phase polymerization as necessary under heating under reduced pressure or in an inert gas stream such as nitrogen. The intrinsic viscosity of the obtained polyester is preferably 0.40 dL / g or more, more preferably 0.40 to 0.90 dL / g.
　本発明のフィルムの総厚みは、フィルムとして製膜可能な範囲で有れば特に限定されるものではないが、通常４～３００μｍ、好ましくは２５～１８８μｍの範囲である。 The total thickness of the film of the present invention is not particularly limited as long as it can be formed as a film, but is usually 4 to 300 μm, preferably 25 to 188 μm.
　次に本発明のフィルムの製造方法に関して具体的に説明するが、本発明の要旨を満足する限り、以下の例示に特に限定されるものではない。 Next, the method for producing the film of the present invention will be specifically described, but it is not particularly limited to the following examples as long as the gist of the present invention is satisfied.
　まず、本発明で使用するポリエステルの製造方法の好ましい例について説明する。ここではポリエステルとしてポリエチレンテレフタレートを用いた例を示すが、使用するポリエステルにより製造条件は異なる。常法に従って、テレフタル酸とエチレングリコールからエステル化し、または、テレフタル酸ジメチルとエチレングリコールをエステル交換反応を行い、その生成物を重合槽に移送し、減圧しながら温度を上昇させ、最終的に真空下で２８０℃に加熱して重合反応を進め、ポリエチレンテレフタレート得る。 First, a preferred example of a method for producing a polyester used in the present invention will be described. Here, an example in which polyethylene terephthalate is used as the polyester is shown, but the production conditions differ depending on the polyester used. According to a conventional method, esterification from terephthalic acid and ethylene glycol or transesterification of dimethyl terephthalate and ethylene glycol is carried out, the product is transferred to a polymerization tank, the temperature is increased while reducing the pressure, and finally vacuum is applied. Under heating to 280 ° C., the polymerization reaction proceeds to obtain polyethylene terephthalate.
　次に例えば上記のようにして得、公知の手法により乾燥したポリエステルチップを溶融押出装置に供給し、それぞれのポリマーの融点以上である温度に加熱し溶融する。次いで、溶融したポリマーを口金から押出し、回転冷却ドラム上でガラス転移温度以下の温度になるように急冷固化し、実質的に非晶状態の未配向シートを得る。この場合、シートの平面性を向上させるため、シートと回転冷却ドラムとの密着性を高めることが好ましく、本発明においては静電印加密着法および／または液体塗布密着法が好ましく採用される。本発明においては、このようにして得られたシートを２軸方向に延伸してフィルム化する。 Next, for example, a polyester chip obtained as described above and dried by a known method is supplied to a melt-extrusion apparatus and heated to a temperature equal to or higher than the melting point of each polymer to melt. Next, the molten polymer is extruded from the die, and rapidly cooled and solidified on the rotary cooling drum so as to have a temperature equal to or lower than the glass transition temperature to obtain a substantially amorphous unoriented sheet. In this case, in order to improve the flatness of the sheet, it is preferable to improve the adhesion between the sheet and the rotary cooling drum. In the present invention, an electrostatic application adhesion method and / or a liquid application adhesion method is preferably employed. In the present invention, the sheet thus obtained is stretched biaxially to form a film.
　延伸条件について具体的に述べると、前記未延伸シートを好ましくは縦方向に７０～１４５℃で２～６倍に延伸し、縦１軸延伸フィルムとした後、横方向に９０～１６０℃で２～６倍延伸を行い、１５０～２４０℃で１～６００秒間熱処理を行うことが好ましい。さらにこの際、熱処理の最高温度ゾーンおよび／または熱処理出口のクーリングゾーンにおいて、縦方向および／または横方向に０．１～２０％弛緩する方法が好ましい。また、必要に応じて再縦延伸、再横延伸を付加することも可能である。さらに、前記の未延伸シートを面積倍率が１０～４０倍になるように同時二軸延伸を行うことも可能である。 Specifically describing the stretching conditions, the unstretched sheet is preferably stretched 2 to 6 times in the machine direction at 70 to 145 ° C. to form a uniaxially stretched film, and then 2 to 90 to 160 ° C. in the transverse direction. The film is preferably stretched up to 6 times and heat-treated at 150-240 ° C. for 1-600 seconds. Further, at this time, it is preferable to relax by 0.1 to 20% in the longitudinal direction and / or the transverse direction in the maximum temperature zone of the heat treatment and / or the cooling zone at the heat treatment outlet. Further, it is possible to add re-longitudinal stretching and re-lateral stretching as necessary. Further, it is possible to simultaneously biaxially stretch the unstretched sheet so that the area magnification is 10 to 40 times.
　本発明のポリエステルフィルムは、本発明の効果を損なわない範囲であれば、延伸工程中にフィルム表面を処理する、いわゆるインラインコーティングを施すこともできる。それは以下に限定するものではないが、例えば、１段目の延伸が終了して、２段目の延伸前に、帯電防止性、滑り性、接着性等の改良、２次加工性改良、耐候性および表面硬度の向上等の目的で、水溶液、水系エマルジョン、水系スラリー等によるコーティング処理を施すことができる。また、フィルム製造後にオフラインコートで各種のコートを行ってもよい。このようなコートは片面、両面のいずれでもよい。コーティングの材料としてはオフラインコーティングの場合は水系、溶媒系のいずれでもよいが、インラインコーティングの場合は水系が好ましい。 The polyester film of the present invention can be subjected to so-called in-line coating in which the film surface is treated during the stretching step as long as the effects of the present invention are not impaired. Although it is not limited to the following, for example, after the first stage of stretching is completed, before the second stage of stretching, improvement of antistatic property, slipperiness, adhesion, etc., secondary workability improvement, weather resistance, etc. In order to improve the property and surface hardness, a coating treatment with an aqueous solution, an aqueous emulsion, an aqueous slurry, or the like can be performed. Various coatings may be performed by offline coating after film production. Such a coat may be either single-sided or double-sided. The coating material may be either water-based or solvent-based for offline coating, but is preferably water-based for in-line coating.
　以下、本発明を実施例によりさらに詳細に説明するが、本発明はその要旨を越えない限り、以下の実施例に限定されるものではない。 Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist.
（１）ポリエステルの極限粘度の測定：
　ポリエステルを１ｇ精秤し、フェノール／テトラクロロエタン＝５０／５０（重量比）の混合溶媒１００ｍＬに溶解させ、３０℃で測定した。 (1) Measurement of intrinsic viscosity of polyester:
1 g of polyester was precisely weighed, dissolved in 100 mL of a mixed solvent of phenol / tetrachloroethane = 50/50 (weight ratio), and measured at 30 ° C.
（２）平均粒径（ｄ５０）：
　島津製作所製遠心沈降式粒度分布測定装置（ＳＡ－ＣＰ３型）を用いて測定した等価球形分布における積算体積分率５０％の粒径を平均粒径ｄ５０とした。 (2) Average particle diameter (d50):
The average particle size d50 was defined as the particle size having an integrated volume fraction of 50% in an equivalent spherical distribution measured using a centrifugal sedimentation type particle size distribution analyzer (SA-CP3 type) manufactured by Shimadzu Corporation.
（３）フィルムの透明度の測定：
　村上色彩技術研究所製の透明度測定器（ＴＭ－１Ｄ小数点以下２桁型：光源波長５４６±５ｎｍ）を用いてＡＳＴＭ　Ｄ１７４６に準じて測定した。 (3) Measurement of transparency of film:
Measurements were made in accordance with ASTM D1746 using a transparency measuring instrument (TM-1D 2-digit type after decimal point: light source wavelength 546 ± 5 nm) manufactured by Murakami Color Research Laboratory.
（４）フィルムの内部透明度の測定：
　村上色彩技術研究所製の透明度測定器（ＴＭ－１Ｄ小数点以下２桁型：光源波長５４６±５ｎｍ）を用いて測定した。測定は、粗面補償溶媒としてエタノールを使用して測定した。すなわち、フィルムをガラスセルにセットし、エタノールに浸漬することで測定した。なお、内部透明度は下記の式で定義される。 (4) Measurement of internal transparency of film:
The measurement was made using a transparency measuring instrument (TM-1D two decimal place type: light source wavelength 546 ± 5 nm) manufactured by Murakami Color Research Laboratory. The measurement was performed using ethanol as a rough surface compensation solvent. That is, it measured by setting a film in a glass cell and immersing in ethanol. The internal transparency is defined by the following formula.
　内部透明度（％）＝（エタノール溶液中にフィルムがあるときの光量／エタノール溶液中にフィルムがないときの光量）×１００ Internal transparency (%) = (light quantity when there is a film in an ethanol solution / light quantity when there is no film in an ethanol solution) × 100
（５）フィルムのヘーズの測定：
　スガ試験機製のヘーズメーター（ＨＺ－２）を用いてＪＩＳ　Ｋ７１３６に準じて測定した。 (5) Measurement of film haze:
Measurement was performed according to JIS K7136 using a haze meter (HZ-2) manufactured by Suga Test Instruments.
（６）フィルムの内部ヘーズの測定：
　スガ試験機製のヘーズメーター（ＨＺ－２）を用いて測定した。測定は、粗面補償溶媒としてエタノールを使用して測定した。すなわち、フィルムをガラスセルにセットし、エタノールに浸漬することで測定した。 (6) Measurement of internal haze of film:
Measurement was performed using a haze meter (HZ-2) manufactured by Suga Test Instruments. The measurement was performed using ethanol as a rough surface compensation solvent. That is, it measured by setting a film in a glass cell and immersing in ethanol.
（７）フィルム表面の粗さ（Ｒａ）の測定：
　Ｒａは、小坂研究所社製表面粗さ測定機（ＳＥ３５００型）を用いて、ＪＩＳ　Ｂ０６０１－１９９４に準じて測定した。なお測定長は２．５ｍｍとした。 (7) Measurement of film surface roughness (Ra):
Ra was measured according to JIS B0601-1994 using a surface roughness measuring machine (SE3500 type) manufactured by Kosaka Laboratory. The measurement length was 2.5 mm.
（８）３波長蛍光灯下でのクリア感観察：
　フィルムに３波長蛍光灯光を透過させてフィルムのクリア感（透明度、鮮明度、粒子感など）を目視観察した。クリア感は下記基準で評価した。
＜判定基準＞
（クリア感高）　○＞△＞×　（クリア感低）
　なお、上記判定基準中、△以上のものが実使用上問題なく使用できるレベルであり、○のものが高透明フィルムとして問題なく使用できるレベルである。 (8) Clear observation under a three-wavelength fluorescent lamp:
Three-wavelength fluorescent lamp light was transmitted through the film, and the clearness (transparency, clarity, particle feeling, etc.) of the film was visually observed. Clearness was evaluated according to the following criteria.
<Criteria>
(Clear feeling high) ○ ＞ △ ＞ × (Clear feeling low)
Of the above criteria, those above Δ are levels that can be used without any problem in actual use, and those with ◯ are levels that can be used without any problem as a highly transparent film.
（７）キズのつきにくさの評価：
　作製したフィルム表面のキズの個数を数え、キズのつきにくさを評価した。評価はＡ４サイズのフィルムを使用して行った。
＜判定基準＞
（キズがつきにくい）　○＞△＞×　（キズがつきやすい）
　○：キズ発生頻度が３本以下
　△：キズ発生頻度が５本以下
　×：キズ発生頻度が５本以上
　なお、上記判定基準中、○以上が実使用上問題なく使用できるレベルである。 (7) Evaluation of scratch resistance:
The number of scratches on the produced film surface was counted, and the difficulty of scratching was evaluated. Evaluation was performed using an A4 size film.
<Criteria>
(It is hard to be scratched) ○ ＞ △ ＞ × (It is easy to be scratched)
○: Scratch occurrence frequency is 3 or less Δ: Scratch occurrence frequency is 5 or less ×: Scratch occurrence frequency is 5 or more In the above criteria, ○ or more is a level that can be used without any problem in actual use.
（８）総合評価：
　前記の（３）～（７）の評価結果を踏まえてフィルム性能を総合的に評価した。 (8) Overall evaluation:
Based on the evaluation results (3) to (7), the film performance was comprehensively evaluated.
　実施例１～４および比較例１～７：
＜ポリエステル（Ａ）の製造＞
　テレフタル酸ジメチル１００重量％とエチレングリコール６０重量％とを出発原料とし、触媒として酢酸マグネシウム四水塩を加えて反応器にとり、反応開始温度を１５０℃とし、メタノールの留去とともに徐々に反応温度を上昇させ、３時間後に２３０℃とした。
　４時間後、実質的にエステル交換反応を終了させた。この反応混合物にエチルアシッドフォスフェートを添加した後、重縮合槽に移し、三酸化アンチモン０．０４部を加えて、４時間重縮合反応を行った。すなわち、温度を２３０℃から徐々に昇温し２８０℃とした。
　一方、圧力は常圧より徐々に減じ、最終的には０．３ｍｍＨｇとした。反応開始後、反応槽の攪拌動力の変化により、極限粘度０．６４ｄＬ／ｇに相当する時点で反応を停止し、窒素加圧下ポリマーを吐出させ、ポリエステルのチップ（Ａ）を得た。この、ポリエステルの極限粘度は０．６４ｄＬ／ｇであった。 Examples 1 to 4 and Comparative Examples 1 to 7:
<Manufacture of polyester (A)>
Starting from 100% by weight of dimethyl terephthalate and 60% by weight of ethylene glycol, magnesium acetate tetrahydrate is added as a catalyst to the reactor, the reaction start temperature is 150 ° C., and the reaction temperature is gradually increased as methanol is distilled off. The temperature was raised to 230 ° C. after 3 hours.
After 4 hours, the transesterification reaction was substantially terminated. Ethyl acid phosphate was added to the reaction mixture, which was then transferred to a polycondensation tank, and 0.04 part of antimony trioxide was added to carry out a polycondensation reaction for 4 hours. That is, the temperature was gradually raised from 230 ° C. to 280 ° C.
On the other hand, the pressure was gradually reduced from normal pressure, and finally 0.3 mmHg. After the start of the reaction, the reaction was stopped at a time corresponding to an intrinsic viscosity of 0.64 dL / g due to a change in the stirring power of the reaction vessel, and the polymer was discharged under nitrogen pressure to obtain a polyester chip (A). The intrinsic viscosity of this polyester was 0.64 dL / g.
＜ポリエステル（Ｂ１～Ｂ４）の製造＞
　ポリエステル（Ａ）の製造方法において、エチルアシッドフォスフェートを添加後、平均粒子径の異なるジビニルベンゼン／メタクリル酸メチル共重合架橋粒子のエチレングリコールスラリーを粒子のポリエステルに対する含有量が０．５重量％となるように添加した以外は、ポリエステル（Ａ）の製造方法と同様の方法を用いてポリエステル（Ｂ１～Ｂ４）を得た。ジビニルベンゼン／メタクリル酸メチル共重合架橋粒子の製法は以下の通りである。メタクリル酸メチル１００部、ジビニルベンゼン２５部、エチルビニルベンゼン２２部、過酸化ベンゾイル１部、トルエン１００部の均一溶液を水７００部に分散させ、次に窒素雰囲気下８０℃で６時間攪拌しながら加熱しながら重合を行った。得られたエステル基を有する架橋高分子粒状体の平均粒径は約０．１ｍｍであった。生成ポリマーを脱塩水で水洗し５００部のトルエンで２回抽出し、少量の未反応モノマー線状ポリマーを除去した。次に、この架橋高分子粒状体をアトライターおよびサンドグラインダーで粉砕することで粒径の異なる平均粒子径０．８、１．４、２．３、４．４μｍのジビニルベンゼン／メタクリル酸メチル共重合架橋粒子を得た。粒径０．８μｍの粒子を含有するポリエステルチップをＢ１、１．４μｍの粒子を含有するチップをＢ２、２．３μｍの粒子を含有するチップをＢ３、４．４μｍの粒子を含有するチップをＢ４とした。得られたポリエステルチップ（Ｂ１～Ｂ４）はいずれも極限粘度０．６２ｄＬ／ｇであった。 <Production of polyester (B1 to B4)>
In the production method of polyester (A), after adding ethyl acid phosphate, the content of ethylene glycol slurry of divinylbenzene / methyl methacrylate copolymer crosslinked particles having different average particle diameters is 0.5% by weight with respect to polyester. Polyesters (B1 to B4) were obtained using the same method as the production method of the polyester (A) except that it was added as described above. The production method of divinylbenzene / methyl methacrylate copolymer crosslinked particles is as follows. A homogeneous solution of 100 parts of methyl methacrylate, 25 parts of divinylbenzene, 22 parts of ethylvinylbenzene, 1 part of benzoyl peroxide and 100 parts of toluene is dispersed in 700 parts of water, and then stirred at 80 ° C. for 6 hours in a nitrogen atmosphere. Polymerization was carried out while heating. The average particle diameter of the obtained crosslinked polymer granules having ester groups was about 0.1 mm. The produced polymer was washed with demineralized water and extracted twice with 500 parts of toluene to remove a small amount of unreacted monomer linear polymer. Next, the crosslinked polymer particles are pulverized with an attritor and a sand grinder to obtain divinylbenzene / methyl methacrylate copolymer having average particle diameters of 0.8, 1.4, 2.3, and 4.4 μm having different particle diameters. Polymerized crosslinked particles were obtained. B1 is a polyester chip containing particles having a particle diameter of 0.8 μm, B2 is a chip containing particles of 1.4 μm, B3 is a chip containing particles of 2.3 μm, and B4 is a chip containing particles of 4.4 μm. It was. The obtained polyester chips (B1 to B4) all had an intrinsic viscosity of 0.62 dL / g.
＜ポリエステル（Ｃ）の製造＞
　ポリエステル（Ｂ）の製造方法において、添加粒子を、平均粒子径２．７μｍのシリカ粒子に、ポリエステルに対する含有量を０．３重量％にした以外は、ポリエステル（Ｂ）の製造方法と同様の方法を用いてポリエステル（Ｄ）を得た。得られたポリエステル（Ｄ）は極限粘度０．６１ｄＬ／ｇであった。 <Manufacture of polyester (C)>
In the method for producing polyester (B), the same method as the method for producing polyester (B), except that the additive particles are silica particles having an average particle diameter of 2.7 μm and the content with respect to the polyester is 0.3% by weight. Was used to obtain a polyester (D). The obtained polyester (D) had an intrinsic viscosity of 0.61 dL / g.
＜ポリエステル（Ｄ）の製造＞
　ポリエステル（Ｂ）の製造方法において、添加粒子を、平均粒子径３．２μｍのシリカ粒子に、ポリエステルに対する含有量を、０．６重量％にした以外は、ポリエステル（Ｂ）の製造方法と同様の方法を用いてポリエステル（Ｄ）を得た。なお、平均粒径はレーザー法により求めた。得られたポリエステル（Ｄ）は極限粘度０．６２ｄＬ／ｇであった。 <Manufacture of polyester (D)>
In the production method of the polyester (B), the additive particles are the same as the production method of the polyester (B) except that silica particles having an average particle diameter of 3.2 μm and the content with respect to the polyester are 0.6% by weight. Polyester (D) was obtained using the method. The average particle size was determined by a laser method. The obtained polyester (D) had an intrinsic viscosity of 0.62 dL / g.
＜フィルムの製造＞
　上記ポリエステル（Ａ）チップと、ポリエステル（Ｂ）、（Ｃ）、（Ｄ）チップとを、表１に示すとおりの割合で混合した混合原料を最外層（表層）および中間層の原料とし、２台の押出機に各々供給し、２８０℃で溶融押出した後、静電印加密着法を用いて表面温度を３０℃に設定した冷却ロール上で冷却固化して未延伸シートを得た。次いで、８５℃にて縦方向に３．５倍延伸した後、テンター内で予熱工程を経て１０５℃で４．３倍の横延伸を施した後、２３５℃で１０秒間の熱処理を行い、幅２５０ｍｍのポリエステルフィルムを各々得た。得られたフィルムの全厚みは５０μｍ、それぞれの層厚みは２．５μｍ／４５μｍ／２．５μｍであった。 <Manufacture of film>
A mixed raw material obtained by mixing the polyester (A) chip and the polyester (B), (C), and (D) chips in the proportions shown in Table 1 is used as a raw material for the outermost layer (surface layer) and the intermediate layer. Each was supplied to an extruder, melt-extruded at 280 ° C., and then cooled and solidified on a cooling roll having a surface temperature set to 30 ° C. using an electrostatic application adhesion method to obtain an unstretched sheet. Next, the film was stretched 3.5 times in the longitudinal direction at 85 ° C., and then subjected to a preheating step in the tenter and 4.3 times transverse stretching at 105 ° C., followed by heat treatment at 235 ° C. for 10 seconds, Each 250 mm polyester film was obtained. The total thickness of the obtained film was 50 μm, and the thickness of each layer was 2.5 μm / 45 μm / 2.5 μm.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　本発明の光学用ポリエステルフィルムは、例えば、タッチパネル表示部材の透明導電性フィルム用ベースフィルムとして好適に利用することができる。 The optical polyester film of the present invention can be suitably used, for example, as a base film for a transparent conductive film of a touch panel display member.

Claims (2)

  1. 　透明度が８３．５％以上であり、一方のフィルム表面の粗さ（Ｒａ）が９．０ｎｍ以上であることを特徴とする光学用ポリエステルフィルム。 An optical polyester film having a transparency of 83.5% or more and a roughness (Ra) of one film surface of 9.0 nm or more.
  2. 　内部透明度が９６．５％以上であり、一方のフィルム表面の粗さ（Ｒａ）が９．０ｎｍ以上であることを特徴とする光学用ポリエステルフィルム。 An optical polyester film having an internal transparency of 96.5% or more and a roughness (Ra) of one film surface of 9.0 nm or more.
PCT/JP2011/079374 2010-12-25 2011-12-19 Polyester film for optical use WO2012086592A1 (en)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003048289A (en) * 2001-08-07 2003-02-18 Mitsubishi Polyester Film Copp Biaxially oriented and laminated polyester film
JP2004250624A (en) * 2003-02-21 2004-09-09 Teijin Dupont Films Japan Ltd Transparent polyester film
JP2005041917A (en) * 2003-07-23 2005-02-17 Toray Ind Inc Plastic film and method for producing the same
JP2008239743A (en) * 2007-03-27 2008-10-09 Toray Ind Inc Polyester film for dry film resist carrier
JP2009214360A (en) * 2008-03-09 2009-09-24 Mitsubishi Plastics Inc Optical laminated polyester film
JP2011148201A (en) * 2010-01-22 2011-08-04 Toyobo Co Ltd Biaxially oriented polyethylene terephthalate film for polarization plate release

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003048289A (en) * 2001-08-07 2003-02-18 Mitsubishi Polyester Film Copp Biaxially oriented and laminated polyester film
JP2004250624A (en) * 2003-02-21 2004-09-09 Teijin Dupont Films Japan Ltd Transparent polyester film
JP2005041917A (en) * 2003-07-23 2005-02-17 Toray Ind Inc Plastic film and method for producing the same
JP2008239743A (en) * 2007-03-27 2008-10-09 Toray Ind Inc Polyester film for dry film resist carrier
JP2009214360A (en) * 2008-03-09 2009-09-24 Mitsubishi Plastics Inc Optical laminated polyester film
JP2011148201A (en) * 2010-01-22 2011-08-04 Toyobo Co Ltd Biaxially oriented polyethylene terephthalate film for polarization plate release

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