JP2009214352A - Laminated optical polyester film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a useful film excellent in visibility when used as a display member, black color taste reproducibility in particular, damage preventing properties, workability, and adhesion to a hard coat layer. <P>SOLUTION: In a laminated optical polyester film, on at least one side of a laminated film composed of at least three polyester layers containing particles in both outermost layers, a coating layer installed in a laminated film forming process is provided, and the SCE value of a wavelength 550 nm of the surface of the coating layer is 0.60% or below. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical laminated polyester film, and in particular, is excellent in visibility when used as a display member such as a display, in particular, black color reproducibility, prevention of scratches, workability, productivity, hard coat layer It is related with the laminated polyester film for optics excellent in adhesiveness.

  Biaxially stretched polyester film is excellent in transparency, dimensional stability, mechanical properties, heat resistance, electrical properties, chemical resistance, etc., packaging materials, electrical insulation materials, metal deposition materials, plate making materials, magnetic recording materials, It is used in many applications, including display materials, transfer materials, and window paste materials.

  Especially recently, for anti-static, anti-reflective, and electromagnetic shielding for pasting the front panel glass surface of so-called flat displays such as base films for prismatic sheets used in transparent touch panels and liquid crystal display devices, cathode ray tubes, LCDs and PDPs. Although it is widely used for various optical uses such as for a base film of a protective film provided with a functional layer such as a polyester film, since a polyester film is easily scratched, there is a drawback that appearance and optical characteristics are easily impaired. In addition, in portable information terminals, mobile phones, and portable game machines, which have recently been increasing in demand, light weight and downsizing and high functionality such as TV function and video playback display are remarkable, optical defects such as scratches are less, and high definition. In addition, high-quality color reproducibility is required.

  Conventionally, a method of adding lubricant particles has been used to prevent scratches on the film surface, but when the amount of lubricant particles added increases, the clearness of the display member disappears, and the black color reproducibility decreases. It is a problem.

JP 2003-48289 A

  The present invention has been made in view of the above circumstances, and its solution is excellent in visibility when used as a display member, particularly black color reproduction, scratch prevention, workability, and hard coat layer. It is in providing the useful film excellent in adhesiveness.

  As a result of intensive studies in view of the above circumstances, the present inventors have found that the above problems can be easily solved by a polyester film having a specific configuration, and have completed the present invention.

  That is, the gist of the present invention is that at least one side of a laminated film comprising at least three polyester layers containing particles in both outermost layers has a coating layer provided in the film-forming process of the laminated film. In the laminated polyester film for optics, the SCE value at a wavelength of 550 nm on the surface of the coating layer is 0.60% or less.

Hereinafter, the present invention will be described in detail.
The laminated polyester film for optics of the present invention needs to be a multilayer film having at least 3 layers. The polyester film of the present invention is a polyester film extruded by a so-called extrusion method that is melt-extruded from an extrusion die, and is a film that is oriented in the biaxial directions of the vertical direction and the horizontal direction as necessary.

  In the present invention, the polyester 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. Typical polyesters include polyethylene terephthalate (PET), polyethylene-2,6-naphthalenedicarboxylate (PEN) and the like.

  The polyester used in the present invention may be a homopolyester or a copolyester. In the case of a copolyester, it is a copolymer containing 30 mol% or less of the third component. Examples of the dicarboxylic acid component of the copolyester include isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, and oxycarboxylic acids (for example, P-oxybenzoic acid). Or 2 or more types are mentioned, As a glycol component, 1 type, or 2 or more types, such as ethylene glycol, diethylene glycol, propylene glycol, butanediol, 1, 4- cyclohexane dimethanol, neopentyl glycol, is mentioned.

  The total thickness of the film of the present invention is usually 50 to 300 μm or more, preferably 75 to 250 μm. When the total thickness of the film is less than 50 μm, since the film is weak, the workability at the time of final inspection performed for each sheet and pasting to a display tends to deteriorate after punching into a sheet, 300 μm If it is thicker, its workability may deteriorate due to its rigidity.

The film of the present invention preferably has an oligomer precipitation amount of 15.0 mg / m ² or less on the film surface in order to improve the durable adhesion of the hard coat layer. In order to make the oligomer precipitation amount on the film surface by heat processing into said range, the method of using polyester with little oligomer content is mentioned. Moreover, in the case of the laminated film by coextrusion, the oligomer precipitation amount on the film surface after heat processing can be suppressed to said range by using polyester with little oligomer content for outermost layer. Specifically, by setting the amount of oligomer contained in the polyester film to 5000 ppm or less, further 4000 ppm, particularly 3000 ppm or less, oligomers deposited on the film surface when heated can be prevented.

  It is known that the oligomer in the polymer increases due to the melting step in film formation, and the increase is strongly influenced by the water content in the polymer, the temperature at the time of melting, the residence time, etc. It is considered to increase by about ˜5000 ppm.

  Also, as the conditions of the melt extrusion process, the moisture content in the polymer should be kept low, the polymer temperature in the extruder should not be higher than the melting point by 20 ° C., the time in the molten state should be shortened, etc. The method can be taken.

  As a method for reducing the amount of oligomer in the polyester, conventionally known solid phase polymerization can be used.

  In the case of a film having a laminated structure, the outermost layer thickness is a thickness on one side only, usually 3 μm or more, and preferably ¼ or less of the total thickness. If the thickness is less than 3 μm, the oligomer (cyclic trimer) contained in the inner layer may be deposited on the film surface due to heat history during processing, etc., and production line contamination and film haze may deteriorate. If the thickness is more than 1/4 of the thickness, the haze value (particularly the internal haze value) due to the lubricant particles blended in the outermost layer film is increased to improve the roll-up property of the film, and the transparency of the film is deteriorated. Tend.

  In the outermost layer of the polyester of the film of the present invention, particles are blended mainly for the purpose of imparting slipperiness and preventing scratches in each step. The kind of the particle to be blended is not particularly limited as long as it is a particle capable of imparting slipperiness. Specific examples thereof include silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, and phosphoric acid. Examples of the particles include magnesium, kaolin, aluminum oxide, and titanium oxide. Further, the heat-resistant organic particles described in JP-B-59-5216, JP-A-59-217755 and the like may be used. Examples of other heat-resistant organic particles include thermosetting urea resins, thermosetting phenol resins, thermosetting epoxy resins, benzoguanamine resins, and the like. Furthermore, precipitated particles obtained by precipitating and finely dispersing a part of a metal compound such as a catalyst during the polyester production process can also be used.

  On the other hand, the shape of the particles to be used is not particularly limited, and any of a spherical shape, a block shape, a rod shape, a flat shape, and the like may be used. Moreover, there is no restriction | limiting in particular also about the hardness, specific gravity, a color, etc. These series of particles may be used in combination of two or more as required.

  Although the average particle diameter of the particle | grains mix | blended in a polyester film is not specifically limited, Usually, 0.02 micrometer-3 micrometers, Preferably it is 0.02 micrometer-2.5 micrometers, More preferably, it is the range of 0.02 micrometer-2 micrometers. is there. 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. When the average particle size exceeds 3 μm, the degree of roughening of the film surface becomes too large and the transparency of the film becomes inferior, and it may not be possible to maintain high quality for optical use. .

  The particle content in the polyester outermost layer is usually in the range of 0.0005 to 0.5% by weight, preferably 0.001 to 0.3% by weight, based on the polyester constituting the outermost layer. When the particle content is less than 0.0005% by weight, the slipperiness of the film may be insufficient. On the other hand, when the content exceeds 0.5% by weight, the transparency of the film is insufficient. It may become.

  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 of 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 completion of the transesterification reaction, The polycondensation 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 blending of dried particles and a polyester raw material using a kneading extruder. It is done by methods.

  Hereinafter, although the manufacturing method of the film of this invention is demonstrated concretely, as long as the summary of this invention is satisfied, this invention is not specifically limited to the following illustrations.

  Polyester chips dried by a known method are 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 a die and rapidly cooled and solidified on a rotary cooling drum so that the temperature is 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. Specifically describing the stretching conditions, the unstretched sheet is preferably stretched 2 to 6 times at 70 to 145 ° C. in the longitudinal direction to form a longitudinal uniaxially stretched film, and then 2 to 90 to 160 ° C. in the lateral direction. It is preferable to perform ~ 6 times stretching and heat treatment at 150 to 240 ° C for 1 to 600 seconds. Further, it is possible to add re-longitudinal stretching and re-lateral stretching as necessary.

  When the polyester film of the present invention is used for optics, it is used with a hard coat layer provided to improve surface hardness. Although the polyester film has a certain degree of adhesion to the coating layer, it needs to have good adhesion to the coating layer in order to maintain high optical properties and durability during use. In the present invention, in order to improve the adhesion with the hard coat layer, it is necessary to provide a coating layer on the polyester film in advance.

  As a method for forming such a coating layer, a so-called in-line coating method in which coating is performed before the tenter entrance (before completion of orientation crystallization) and drying is performed in the tenter is preferable.

  The coating layer for improving the adhesion with the hard coat layer is not particularly limited as long as it improves the adhesion, but a binder resin as described in JP-A-2003-201357. A combination of and a crosslinking agent is preferred.

  In the present invention, it is preferable to contain inorganic particles or organic particles in the coating layer in order to further improve the slipperiness, adhesion and the like. The amount of the particles in the coating agent is usually 0.5 to 10% by weight, preferably 1 to 5% by weight. When the blending amount is less than 0.5% by weight, the blocking resistance may be insufficient. When the blending amount exceeds 10% by weight, the transparency of the film is hindered and the sharpness of the image tends to be lowered.

  Examples of the inorganic particles include silicon dioxide, alumina, zirconium oxide, kaolin, talc, calcium carbonate, titanium oxide, barium oxide, carbon black, molybdenum sulfide, and antimony oxide. Among these, silicon dioxide is easy to use because it is inexpensive and has various particle sizes.

  Examples of the organic particles include polystyrene or polyacrylate polymethacrylate in which a crosslinked structure is achieved by a compound (for example, divinylbenzene) containing two or more carbon-carbon double bonds in one molecule.

  The above inorganic particles and organic particles may be surface-treated. Examples of the surface treatment agent include a surfactant, a polymer as a dispersant, a silane coupling agent, a titanium coupling agent, and the like. The content of the particles in the coating layer is preferably 10% by weight or less, more preferably 5% by weight or less as an appropriate addition amount that does not impair the transparency.

  The coating layer may contain an antifoaming agent, a coating property improving agent, a thickener, an antioxidant, an ultraviolet absorber, a foaming agent, a dye, a pigment, and the like.

  As long as water is the main medium, the coating agent may contain a small amount of an organic solvent for the purpose of improving dispersion in water or improving the film-forming performance. It is necessary to use the organic solvent as long as it is soluble in water. Examples of the organic solvent include aliphatic or alicyclic alcohols such as n-butyl alcohol, n-propyl alcohol, isopropyl alcohol, ethyl alcohol, and methyl alcohol, glycols such as propylene glycol, ethylene glycol, and diethylene glycol, n-butyl cellosolve, Examples include glycol derivatives such as ethyl cellosolve, methyl cellosolve, propylene glycol monomethyl ether, ethers such as dioxane and tetrahydrofuran, esters such as ethyl acetate and amyl acetate, ketones such as methyl ethyl ketone and acetone, and amides such as N-methylpyrrolidone. Can be mentioned. These organic solvents may be used in combination of two or more as required.

  Moreover, you may perform various coatings by offline coating after manufacture of a film as needed. Such a coat may be either single-sided or double-sided. The coating material may be either water-based and / or solvent-based for off-line coating, but is preferably water-based or water-dispersed for in-line coating.

  In addition, when the polyester film of the present invention is used for optics, an antistatic agent, a colorant, a conductive material, etc. may be added for the purpose of imparting other functionality to the hard coat layer provided for improving the surface hardness. In addition, a functional multilayer thin film may be formed thereon for the purpose of reflection of external light, electric shock due to static electricity, dust adhesion prevention, and electromagnetic wave shielding.

  The coating liquid used in the present invention is preferably an aqueous solution or an aqueous dispersion in terms of handling and working environment, but contains water as the main medium and contains an organic solvent as long as it does not exceed the gist of the present invention. You may do it.

  Although there is no restriction | limiting in particular in the solid content density | concentration of a coating liquid, Usually, 0.3 to 65 weight%, Preferably it is 0.5 to 30 weight%, More preferably, it is 1 to 20 weight%. When the concentration is too high or too low than these ranges, it may be difficult to provide a coating layer having a thickness necessary for fully expressing the function.

  The thickness of a coating layer is dry thickness, and is 0.003-1.5 micrometers normally, Preferably it is 0.01-0.5 micrometer, More preferably, it is 0.01-0.3 micrometer. If the thickness of the coating layer is less than 0.003 μm, sufficient performance may not be obtained. If the thickness exceeds 1.5 μm, blocking between films tends to occur.

  As a coating method of the coating agent, for example, a reverse roll coater, a gravure coater, a rod coater, an air doctor coater, or a coating apparatus other than these as shown in Yuji Harasaki, Tsuji Shoten, published in 1979, “Coating Method” Can be used.

  The SCE value at a wavelength of 550 nm on the surface of the coating layer of the film of the present invention needs to be 0.60% or less, preferably 0.59% or less, more preferably 0.58% or less. The SCE value referred to here refers to a reflectance value excluding regular reflection light when the reflectance is measured with a spectrocolorimeter. The film of the present invention is widely used in optical applications because of its excellent transparency. However, when the SCE value exceeds 0.60%, black color reproducibility is inferior, and it is not suitable as an optical display member. It becomes appropriate.

  The polyester film of the present invention can be mixed with other thermoplastic resins such as polyethylene naphthalate and polytrimethylene terephthalate as long as the effects of the present invention are not impaired. Moreover, you may mix | blend coloring agents, such as a ultraviolet absorber, antioxidant, surfactant, a fluorescent whitening agent, a lubricant agent, a light-shielding agent, a matting agent, and a dye and a pigment. In addition, for the purpose of improving the slipperiness and abrasion resistance of the film, inert inorganic or organic fine particles can be added to the polyester as necessary.

  According to the polyester film of the invention, it is possible to provide a useful film that is excellent in visibility as a display member, black color reproducibility, has few scratches on the film surface, and has excellent workability. Industrial value is high.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example, unless the summary is exceeded. In the examples and comparative examples, “parts” means “parts by weight”. The measuring method used in the present invention is as follows.

(1) Measurement of intrinsic viscosity of polyester 1 g of polyester from which other polymer components and pigments incompatible with polyester have been removed are precisely weighed, and 100 ml of a mixed solvent of phenol / tetrachloroethane = 50/50 (weight ratio) is added. It was dissolved and measured at 30 ° C.

(2) Average particle diameter (d50)
The particle size was measured by a sedimentation method based on Stokes' resistance law using a centrifugal sedimentation type particle size distribution analyzer SA-CP3 manufactured by Shimadzu Corporation.

(3) Content of oligomer (cyclic trimer) in polyester After a predetermined amount of polyester raw material or polyester film was dissolved in o-chlorophenol, it was reprecipitated with tetrahydrofuran and filtered to remove linear polyethylene terephthalate. After that, the filtrate obtained was supplied to liquid chromatography (Shimadzu LC-7A) to determine the amount of oligomer (cyclic trimer) contained in the polyester, and this value was divided by the amount of polyester used for the measurement. The amount of oligomer contained in the polyester (cyclic trimer). The amount of oligomer (cyclic trimer) determined by liquid chromatography was determined from the peak area ratio between the standard sample peak area and the measured sample peak area (absolute calibration curve method). The standard sample was prepared by accurately weighing an oligomer (cyclic trimer) collected in advance and dissolving it in accurately measured DMF (dimethylformamide). The conditions of the liquid chromatograph were as follows.

Mobile phase A: Acetonitrile Mobile phase B: 2% acetic acid aqueous solution Column: MCI GEL ODS 1HU manufactured by Mitsubishi Chemical Corporation
Column temperature: 40 ° C
Flow rate: 1 ml / min Detection wavelength: 254 nm

(4) Thickness of Laminated Polyester Layer After fixing a small piece of film with an epoxy resin, it was cut with a microtome and the cross section of the film was observed with a transmission electron micrograph. Two of the cross-sections are observed in parallel with the film surface, and the interface is observed by light and dark. The distance between the two interfaces and the film surface was measured from 10 photographs, and the average value was defined as the laminated thickness.

(5) Hard coat adhesion The hard coat resin was applied on the coating layer of the obtained film so that the thickness after curing was 3 μm, and the irradiation distance was 150 mm using a high-pressure mercury lamp with an energy of 120 W / cm. Was irradiated for about 15 seconds to obtain a hard coat film. As the hard coat layer resin, a composition comprising 30 parts of dipentaerythritol hexaacrylate, 40 parts of tetrafunctional urethane acrylate, 27 parts of bisphenol A type epoxy acrylate and 3 parts of 1-hydroxycyclohexyl phenyl ketone was used. The hard coat layer was cross-cut so that there were 100 grids in a 1-inch width, and immediately, a cellotape (registered trademark) rapid peel test was performed three times on the same location, and the peel area was evaluated. The judgment criteria are as follows.

○: Number of cross cuts = 0
Δ: 1 ≦ number of cross-cuts ≦ 20
×: 21 <Number of cross-cuts peeled

(6) Film haze Turbidity was measured with an integrating sphere turbidimeter NDH manufactured by Nippon Denshoku Industries Co., Ltd. according to JIS K 7136.

(7) SCE value A black tape manufactured by Nichiban Co., Ltd. was attached to the back surface of the measurement surface, and an SCE value of 550 nm was measured using a spectrocolorimeter CM-3700d manufactured by Konica Minolta.

(8) Black color evaluation A black tape manufactured by Nichiban Co., Ltd. was applied to the back of the hard coat layer of the hard coat film obtained by the same method as in (5) above, and the black on the hard coat surface side under an indoor fluorescent lamp. The color was visually judged according to the following criteria.

○: Clear feeling and vivid black color ×: No clear feeling, black color is blurred

<Manufacture of polyester>
[Method for producing ester (A)]
Using 100 parts by weight of dimethyl terephthalate and 60 parts by weight of ethylene glycol as starting materials, 0.09 parts by weight of magnesium acetate tetrahydrate as a catalyst is placed in the reactor, the reaction start temperature is set to 150 ° C., and the methanol is distilled off gradually. The reaction temperature was raised to 230 ° C. after 3 hours. After 4 hours, the transesterification reaction was substantially terminated. After adding 0.04 part of ethyl acid phosphate to this reaction mixture, 0.04 part of antimony trioxide was added, and a polycondensation reaction was carried out 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 0.63 due to a change in stirring power of the reaction tank, and the polymer was discharged under nitrogen pressure. The intrinsic viscosity of the obtained polyester (A) was 0.63, and the content of the oligomer (cyclic trimer) was 0.83% by weight.

[Production method of polyester (B)]
Polyester (A) is pre-crystallized at 160 ° C. in advance, and then solid-phase polymerized in a nitrogen atmosphere at a temperature of 220 ° C., limiting viscosity 0.75, oligomer (cyclic trimer) content 0.24% by weight. Polyester (B) was obtained.

[Production method of polyester (C)]
In the method for producing polyester (A), after adding 0.04 part of ethyl acid phosphate, 0.2 part of silica particles dispersed in ethylene glycol having an average particle diameter of 1.6 μm and 0.04 part of antimony trioxide are added. In addition, polyester (C) was obtained using the same method as the production method of polyester (A) except that the polycondensation reaction was stopped at the time corresponding to the intrinsic viscosity of 0.65. The obtained polyester (C) had an intrinsic viscosity of 0.65 and an oligomer (cyclic trimer) content of 0.82% by weight.

(Coating agent adjustment)
Aqueous coating solution a
(Terephthalic acid / isophthalic acid / 5-sodium sulfoisophthalic acid / ethylene glycol / 1,4-butanediol / diethylene glycol = polyester dispersion at 28/20/2/35/10/5 molar ratio) / (methyl methacrylate / Emulsion polymer of ethyl acrylate / acrylonitrile / N-methylol methacrylamide = 45/45/5/5 molar ratio [emulsifier = anionic surfactant] / hexamethoxymethylmelamine / silica sol having an average particle size of 0.08 μm as a solid content An aqueous coating solution containing 47/20/30/3 in terms of weight ratio in terms of weight.

Example 1:
Two extruders using a mixed raw material in which the polyesters (B) and (C) are mixed at a ratio of 95% and 5%, respectively, as a raw material for the A layer and a raw material of 100% polyester (A) as the raw material for the B layer. Each was supplied to each and melted at 285 ° C., then the A layer was the outermost layer (surface layer), the B layer was the intermediate layer, and the two layers and three layers (ABA) were formed on a casting drum cooled to 40 ° C. A non-oriented sheet was obtained by coextrusion and cooling and solidification so that the composition ratio was A: B: A = 5: 90: 5.

Next, the film is stretched 3.4 times in the machine direction at a film temperature of 82 ° C. using the roll peripheral speed difference, and then the coating amount after transverse stretching and drying is 0.1 g / m ^{2 on} both surfaces of the machined film. After applying the aqueous coating agent a with the adjusted concentration of the solution, it was led to a tenter, stretched 3.7 times at 120 ° C in the transverse direction, heat treated at 230 ° C, and then relaxed at 0% in the transverse direction. The rail width was fixed, and the film was rolled up at a production rate of 30 m / min to obtain a laminated polyester film having a thickness of 125 μm and a film haze of 0.5% having coating layers on both sides. The surface of the obtained film had almost no scratches visible under a three-wavelength fluorescent lamp. The evaluation results are shown in Table 1 below.

Example 2:
In Example 1, a polyester film was obtained in the same manner as in Example 1 except that the raw material for the A layer was polyester (B) / polyester (C) = 97.5 / 2.5. The film obtained had a film haze value of 0.4%, and the surface had almost no scratches visible under a three-wavelength fluorescent lamp.

Comparative Example 1:
In Example 1, the polyester film was obtained by the same method as Example 1 except having made the raw material of the A layer into polyester (B) / polyester (C) = 80/20. The obtained film had a film haze of 1.1%, and the surface had almost no scratches visible under a three-wavelength fluorescent lamp.

Comparative Example 2:
In Example 1, a polyester film was obtained in the same manner as in Example 1 except that the raw material for the A layer was polyester (B) / polyester (C) = 87.5 / 12.5. The film obtained had a film haze of 0.7%, and the surface had almost no scratches visible under a three-wavelength fluorescent lamp.

Comparative Example 3:
In Example 1, the polyester film was obtained by the same method as Example 1 except having made only the polyester (B) the raw material of A layer. The film obtained had a film haze of 0.3%, and there were many scratches visible on the surface under a three-wavelength fluorescent lamp, and the film was not of high quality as an optical film.

Comparative Example 4:
In Example 1, a polyester film was obtained in the same manner as in Example 1 except that the coating liquid a was not applied. The obtained film had a film haze of 0.5%, and the surface had almost no scratches visible under a three-wavelength fluorescent lamp.

  The film of the present invention can be suitably used as a display member such as a display, for example.

Claims (1)

At least one side of a laminated film composed of at least three polyester layers containing particles in both outermost layers has a coating layer provided in the film forming step of the laminated film, and the wavelength of the coating layer surface is 550 nm. An optically laminated polyester film having an SCE value of 0.60% or less.