JP2006175628A - Polyester film for antireflection film and antireflection film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antireflection film suitable in various optical uses for the production of a display member such as a liquid crystal display (LCD), a plasma display panel (PDP), organic electroluminescence (organic EL) or the like reduced in the interference irregularity due to the reflection of external light. <P>SOLUTION: The antireflection film is a polyester film having an easy adhesive layer provided at least on its one side and characterized in that a compound having a condensed polycyclic aromatic group is added to the easy adhesive layer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an antireflection film with reduced interference unevenness, for example, a liquid crystal display (hereinafter abbreviated as LCD), a plasma display panel (hereinafter abbreviated as PDP), organic electroluminescence (hereinafter referred to as organic). The present invention provides an antireflection film suitable for optical applications such as for the production of display members such as EL.

Conventionally, an antireflection film using a polyester film as a substrate has been used for various optical applications including production of display members such as liquid crystal polarizing plates, retardation plates, PDPs, and organic ELs.
These antireflection films are required to have excellent transparency and visibility.

  In recent years, with the advancement of IT (Information Technology) field, various problems due to deterioration in visibility due to external light reflection and improved quality of laminated polyester film used when manufacturing display members such as LCD, PDP and organic EL It tends to become.

When a polyester film with an easy-adhesion layer is used as the substrate for various antireflection films, high-quality and high-precision video displays due to recent digitization of images are easily affected by external light reflection, resulting in poor visibility. There is. In general, external light reflection is prevented by processing an antireflection layer on the surface or glare-treating the surface. Since glare treatment cannot handle high-quality images, an antireflection treatment layer is often processed on the surface. The antireflection layer uses the light interference phenomenon by alternately laminating a high refractive index layer and a low refractive index layer to prevent reflection of external light.
Usually, sputtering, wet processing with sol-gel, etc. are performed several times to create a laminate.

  On the other hand, polyester films generally have poor adhesion to other materials, such as anti-reflection layers and hard coats mainly composed of acrylic resins, so polyester resins, acrylic resins, urethane resins, etc. are laminated on polyester films. It has been proposed to use them (for example, Patent Documents 1 and 2).

In the conventional lamination with the resin as described above, the refractive index is fixed at around 1.50. Therefore, when designing the antireflection film, the antireflection performance is limited, and the interference unevenness due to the reflection of external light is remarkable. May occur. When a film in which interference unevenness due to reflection of external light is remarkably generated is used as a display member for LCD, PDP, organic EL, etc., various problems due to deterioration in visibility tend to become more apparent. In addition, the remarkable occurrence of interference unevenness not only deteriorates the visibility, but may also cause eye fatigue and health problems.
JP-A-10-119215 JP 2000-246855 A

  The present invention has been made in view of the above-described circumstances, and the solution is to reduce various types of display components such as LCDs, PDPs, organic ELs, and other display members that have reduced interference unevenness due to external light reflection. An object of the present invention is to provide an antireflection film suitable for various optical applications in addition to material production.

  As a result of intensive studies in view of the above situation, the present inventors have found that the use of an antireflection film having a specific configuration can easily solve the above-described problems, and have completed the present invention.

  That is, the gist of the present invention is a polyester film for an antireflection film characterized in that it is a polyester film having an easy-adhesion layer on at least one surface, and the easy-adhesion layer contains a compound having a condensed polycyclic aromatic. Exist.

Hereinafter, the present invention will be described in more detail.
The polyester film constituting the antireflection film in the present invention may have a single-layer structure or a laminated structure, and may have four or more layers as long as the gist of the present invention is not exceeded other than the two-layer or three-layer structure. It may be a multilayer, and is not particularly limited.

  The polyester used in the present invention may be a homopolyester or a copolyester. In the case of a homopolyester, those obtained by polycondensation of an aromatic dicarboxylic acid and an aliphatic glycol are preferred. 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 polyester includes polyethylene terephthalate and the like. On the other hand, 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 acid (eg, p-oxybenzoic acid). 1 type or 2 types or more are mentioned, As a glycol component, 1 type or 2 types or more, such as ethylene glycol, diethylene glycol, propylene glycol, butanediol, 4-cyclohexane dimethanol, neopentyl glycol, is mentioned. In any case, the polyester referred to in the present invention refers to a polyester that is usually 60 mol% or more, preferably 80 mol% or more of polyethylene terephthalate or the like which is an ethylene terephthalate unit.

  In the polyester layer of the film of the present invention, it is preferable to blend particles for the main purpose of imparting slipperiness. 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 about the hardness, specific gravity, a color, etc. These series of particles may be used in combination of two or more as required.

  Moreover, the average particle diameter of the particle | grains to be used is 0.01-3 micrometers normally, Preferably it is the range of 0.01-1 micrometer. When the average particle diameter is less than 0.01 μm, the particles are likely to aggregate and dispersibility may be insufficient. On the other hand, when the average particle diameter exceeds 3 μm, the surface roughness of the film becomes too rough and Problems may occur when various surface functional layers are applied in the process.

  Further, the content of particles in the polyester layer is usually in the range of 0.001 to 5% by weight, preferably 0.005 to 3% by weight. When the particle content is less than 0.001% by weight, the slipperiness of the film may be insufficient. On the other hand, when the content exceeds 5% by weight, the transparency of the film is insufficient. There is.

  The method for adding particles to the polyester layer is not particularly limited, and a conventionally known method can be adopted. For example, it can be added at any stage for producing the polyester constituting each layer, but it is preferably added after completion of esterification or transesterification.

  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.

  In addition to the above-mentioned particles, conventionally known antioxidants, antistatic agents, thermal stabilizers, lubricants, dyes, pigments, and the like can be added to the polyester film in the present invention as necessary.

  Although the thickness of the polyester film in this invention will not be specifically limited if it is a range which can be formed into a film, Usually, 5-250 micrometers, Preferably it is the range of 5-200 micrometers.

  Next, although the manufacture example of the polyester film in this invention is demonstrated concretely, it is not limited to the following manufacture examples at all. That is, a method of using the polyester raw material described above and cooling and solidifying a molten sheet extruded from a die with a cooling roll to obtain an unstretched sheet is preferable. In this case, in order to improve the flatness of the sheet, it is necessary to improve the adhesion between the sheet and the rotary cooling drum, and an electrostatic application adhesion method and / or a liquid application adhesion method are preferably employed. Next, the obtained unstretched sheet is stretched in the biaxial direction. In that case, first, the unstretched sheet is stretched in one direction by a roll or a tenter type stretching machine. The stretching temperature is usually 70 to 120 ° C., preferably 80 to 110 ° C., and the stretching ratio is usually 2.5 to 7 times, preferably 3.0 to 6 times. Next, the film is stretched in the direction perpendicular to the first stretching direction. In that case, the stretching temperature is usually 70 to 170 ° C., and the stretching ratio is usually 3.0 to 7 times, preferably 3.5 to 6 times. is there. Subsequently, heat treatment is performed at a temperature of 180 to 270 ° C. under tension or under relaxation within 30% to obtain a biaxially oriented film. In the above-described stretching, a method in which stretching in one direction is performed in two or more stages can be employed. In that case, it is preferable to carry out so that the draw ratios in the two directions finally fall within the above ranges.

  In the present invention, the simultaneous biaxial stretching method can be adopted for the production of the polyester film constituting the laminated polyester film. The simultaneous biaxial stretching method is a method in which the above-mentioned unstretched sheet is usually stretched and oriented in the machine direction and the width direction at a temperature controlled normally at 70 to 120 ° C., preferably 80 to 110 ° C. Is 4 to 50 times, preferably 7 to 35 times, and more preferably 10 to 25 times in terms of area magnification. Subsequently, heat treatment is performed at a temperature of 170 to 250 ° C. under tension or under relaxation within 30% to obtain a stretched oriented film. With respect to the simultaneous biaxial stretching apparatus that employs the above-described stretching method, conventionally known stretching methods such as a screw method, a pantograph method, and a linear drive method can be employed.

  Furthermore, what is called an in-line coating which processes the film surface during the extending | stretching process of the above-mentioned polyester film can be given. When an easy-adhesion layer is provided on a polyester film by in-line coating, the film can be applied simultaneously with stretching, and the thickness of the easy-adhesion layer can be changed by the stretching ratio. Can be manufactured.

  Next, formation of the easily bonding layer which comprises the antireflection film in this invention is demonstrated. As for the easy-adhesion layer, it may be provided on the polyester film by the above-mentioned in-line coating, or a so-called off-line coating applied outside the system on the film once manufactured may be employed, or both may be used in combination. . In-line coating is preferably used because it can be manufactured at low cost.

  The in-line coating is not limited to the following, but for example, in the sequential biaxial stretching, the coating treatment can be performed particularly before the lateral stretching after the longitudinal stretching is finished. When an easy-adhesion layer is provided on a polyester film by in-line coating, it becomes possible to apply simultaneously with film formation, and the easy-adhesion layer can be treated at a high temperature, so that a film suitable as a polyester film can be produced.

  In the present invention, it is an essential requirement that the easy-adhesion layer contains a compound having a condensed polycyclic aromatic.

  A specific example of the condensed polycyclic aromatic is a compound having a structure represented by the following formula.

  In consideration of applicability on the polyester film, the compound having a condensed polycyclic aromatic is preferably a polymer compound such as a polyester resin, an acrylic resin, or a urethane resin. In particular, polyester resins are more preferable because more condensed polycyclic aromatics can be introduced.

  As a method of incorporating the condensed polycyclic aromatic into the polyester resin, for example, two or more hydroxyl groups are introduced into the condensed polycyclic aromatic as a substituent to form a diol component or a polyvalent hydroxyl component, or There is a method in which two or more acid groups are introduced to prepare a dicarboxylic acid component or a polyvalent carboxylic acid component.

  In the laminated polyester film production process, the condensed polycyclic aromatic contained in the easy-adhesion layer is preferably a compound having a naphthalene skeleton in that it is difficult to be colored. In addition, a resin incorporating a naphthalene skeleton as a polyester constituent is preferably used in terms of good adhesion to various surface functional layers laminated on the easy-bonding surface. Representative examples of the naphthalene skeleton include 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid.

  In the laminated polyester film of the present invention, an organic compound having a metal element can be used in combination in order to improve the antireflection performance and transparency when various surface functional layers are laminated on the easy adhesion layer.

  Specific examples of the organic compound having a metal element include aluminum such as aluminum acetylacetonate, hydroxyaluminum diacetate, and dihydroxyaluminum acetate; tetranormal butyl titanate, tetraisopropyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate , Titanium such as tetramethyl titanate, titanium acetylacetonate, titanium tetraacetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, titanium lactate, titanium triethanolaminate, titanium ethylacetoacetate; iron acetylacetonate Irons such as iron acetate; copper acetate, copper acetate monohydrate, copper acetate multihydrate, copper acetylate Coppers such as tonates; zincs such as zinc acetate, zinc acetate dihydrate, zinc acetylacetonate hydrate; zirconium acetate, zirconium normal propyrate, zirconium normal butyrate, zirconium tetraacetylacetonate, zirconium monoacetylacetonate And zirconium such as zirconium bisacetylacetonate. As the metal element, it is more preferable to use a metal having a higher specific gravity than a metal having a lower specific gravity.

  Among the organic compounds having the above metal elements, in particular, the organic compound having a titanium element and the organic compound having a zirconium element are preferable in that the antireflection performance is good, and more preferably in consideration of application to inline coating, A water-soluble titanium chelate compound, a water-soluble zirconium acetate compound and the like are preferably used. It is also described in detail in the “Crosslinking agent handbook” (Yamashita Shinzo, Kaneko East Assistant Editor, Taiseisha 1990 edition).

  In the laminated polyester film of the present invention, a binder for improving the antireflection performance and transparency when various surface functional layers are laminated on the easy-adhesion layer, and improving the adhesion to various surface functional layers. It is preferable to use a polymer together.

  The “binder polymer” used in the present invention is a number average molecular weight (measured by gel permeation chromatography (GPC) measurement) according to a polymer compound safety evaluation flow scheme (sponsored by the Chemical Substance Council in November 1985). It is defined as a polymer compound having a Mn) of 1000 or more and having a film-forming property.

  Specific examples of the binder polymer include polyester resin, acrylic resin, urethane resin, polyvinyl (polyvinyl alcohol, polyvinyl chloride, vinyl chloride vinyl acetate copolymer, etc.), polyalkylene glycol, polyalkylene imine, methyl cellulose, hydroxy cellulose, and starch. And the like.

  Furthermore, in the easy-adhesion layer, a cross-linking agent may be used in combination as long as the gist of the present invention is not impaired. Specific examples include a methylolated or alkylolated urea, melamine, guanamine, acrylamide, Polyamide compounds, oxazoline compounds, epoxy compounds, aziridine compounds, block polyisocyanates, silane coupling agents and the like can be mentioned. These crosslinking components may be previously bonded to the binder polymer.

  In addition, for the purpose of improving the adhesion and slipperiness of the easy-adhesion layer, inert particles may be contained, and specific examples include silica, alumina, kaolin, calcium carbonate, titanium oxide, organic particles, and the like.

  Furthermore, as long as it does not impair the gist of the present invention, an antifoaming agent, a coating property improver, a thickener, an organic lubricant, an antistatic agent, an antioxidant, an ultraviolet absorber, a foaming agent, a dye, etc. May be contained.

  Regarding the total of the compounds having a condensed polycyclic aromatic compound in the easy-adhesion layer constituting the laminated polyester film in the present invention, it is preferable that the following formula (1) is satisfied.

10 ≦ W ≦ 100 (1)
(W in the above formula represents the content (% by weight) of the compound having a condensed polycyclic aromatic in the easy-adhesion layer constituting the laminated polyester film)

  It is preferable to produce a laminated polyester film by coating the above-mentioned series of compounds as a solution or dispersion on a polyester film with a coating solution adjusted to a solid content concentration of about 0.1 to 50% by weight. .

  Furthermore, in the case of in-line coating, the above-described series of compounds is used as an aqueous solution or water dispersion, and the coating solution adjusted with a solid content concentration of about 0.1 to 50% by weight as a guide is laminated on the polyester film. It is preferred to produce a polyester film. Moreover, in the range which does not impair the main point of this invention, a small amount of organic solvents may be contained in the coating liquid for the purpose of improving dispersibility in water, improving film-forming properties, and the like. Only one type of organic solvent may be used, or two or more types may be used as appropriate.

Although there is no restriction | limiting in the application quantity (after drying) of the easily bonding layer provided on a polyester film regarding the laminated polyester film in this invention, Usually 0.005-1g / m < ² >, Preferably 0.005-0.5g / it is in the range of m ^2. When the coating amount is less than 0.005 g / m ² , the uniformity of the coating thickness may be insufficient. On the other hand, when the coating is applied in excess of 1 g / m ² , problems such as a decrease in slipperiness may occur.

  In the present invention, a method for providing an easy-adhesion layer may be a conventionally known coating method such as reverse gravure coating, direct gravure coating, roll coating, die coating, bar coating, or curtain coating. Regarding the coating method, there is a description example in “Coating method” published by Yasuharu Harasaki in 1979.

  In the present invention, the drying and curing conditions for forming the easy-adhesion layer on the polyester film are not particularly limited. For example, when the easy-adhesion layer is provided by off-line coating, it is usually 3 at 80 to 200 ° C. The heat treatment may be performed for ˜40 seconds, preferably 100 to 180 ° C. for 3 to 40 seconds.

  On the other hand, when an easy-adhesion layer is provided by in-line coating, heat treatment is usually performed at 70 to 280 ° C. for 3 to 200 seconds as a guide.

  Further, irrespective of off-line coating or in-line coating, heat treatment and active energy ray irradiation such as ultraviolet irradiation may be used in combination as required. The polyester film constituting the laminated polyester film in the present invention may be subjected to surface treatment such as corona treatment or plasma treatment in advance.

  The reflectance of the polyester film on which the easy adhesion layer is laminated is 4.0% or more, preferably 4.5% or more, more preferably 5.0% or more at an arbitrary wavelength of 350 to 800 nm. When the wavelength is plotted on the horizontal axis and the reflectance is plotted on the vertical axis, it is represented by a curve having a minimum value between 400 and 700 nm, and the difference between the maximum value and the minimum value between 400 and 700 nm is 2.0%. Are preferred. When the reflectance is below 4.0%, or when there is no minimum value between 400 and 700 nm, or when the difference between the maximum value and the minimum value between 400 and 700 nm exceeds 2.0%, When a hard coat layer and an antireflection layer are laminated on the easy-adhesion layer of the film to form an antireflection film, interference unevenness becomes strong and visibility may be lowered.

  The hard coat layer in the present invention is formed on the polyester film on which the easy-adhesion layer formed as described above is laminated, and a commonly used constituent material can be used. For example, there is one made of an ultraviolet curable resin. Examples of the ultraviolet curable resin include ultraviolet curable compositions such as polyester-acrylate, urethane-acrylate, and epoxy-acrylate.

  As a method for providing the hard coat layer, a conventionally known coating method such as reverse gravure coating, direct gravure coating, roll coating, die coating, bar coating, curtain coating or the like can be used.

  The coating thickness of the hard coat layer is usually in the range of 0.5 to 20 μm, and more preferably 5 to 15 μm. If the thickness is less than 0.5 μm, a hard coat property failure may occur due to insufficient surface hardness. If the thickness exceeds 20 μm, the internal stress becomes stronger, and the flexibility of the entire film is lost. In some cases, problems such as generation of cracks and poor adhesion may occur.

  The antireflection layer in the present invention is formed on the hard coat layer formed as described above, and is formed by alternately laminating a high refractive index layer and a low refractive index layer. Examples of components constituting the high refractive index layer include metal oxides such as titanium oxide, tin oxide, indium oxide, zinc oxide, and indium-tin oxide. Examples of the constituent component of the low refractive index layer include silicon oxide and organic resin. As a method for providing the antireflection layer, a sputtering method, a vacuum evaporation method, an ion beam method, or the like can be used.

  Further, the total light transmittance of the antireflection film in the present invention is 80% or more, and transparency is particularly required for optical applications such as used in the production of display members such as LCD, PDP, and organic EL. It is preferable because it can be used for applications, and more preferably 85% or more. When the total light transmittance is less than 80%, the transparency becomes insufficient. For example, when used in an inspection process involving optical evaluation, there may be a problem that foreign matters are easily overlooked.

  According to the antireflection film of the present invention, when used in optical applications such as a display member, an antireflection film with reduced interference unevenness can be provided, and its 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. The measurement method and evaluation method used in the present invention are 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) Measurement of average particle diameter (d ₅₀ : μm) Integration (weight basis) 50% in equivalent spherical distribution measured using centrifugal sedimentation type particle size distribution measuring device (SA-CP3 type manufactured by Shimadzu Corporation) Was the average particle size.

(3) Measurement of reflectance from one easy-adhesion layer surface in a polyester film In advance, a black tape (vinyl tape VT-50 manufactured by Nichiban Co., Ltd.) is pasted on the measurement back surface of the polyester film, and a spectrophotometer (Shimadzu Corporation) The reflectance in a wavelength range of 350 to 800 nm measured using a UV-3100PC type manufactured by the company was measured.

(4) Measuring method of reflectance The reflectance in a wavelength range of 350 to 800 nm was measured, and the minimum value and the measurement wavelength at which the minimum value was determined were determined. Further, the difference between the maximum value and the minimum value of the reflectance in the wavelength range of 400 to 700 nm was also measured and calculated.

(5) Evaluation method of antireflection ability of antireflection film 45:40:10 by weight of pentaerythritol acrylate: N-methylolacrylamide: N-vinylpyrrolidone: 1-hydroxycyclohexylphenylketone : A UV curable composition consisting of 5 was uniformly applied so that the film thickness after curing was 5 μm, and then hardened by irradiating with UV light for 30 seconds with a high-pressure mercury lamp having an intensity of 80 W / cm. A layer was formed. On the hard coat layer, a low refractive index layer (SiO ₂ , 30 nm), a high refractive index layer (TiO ₂ , 30 nm), a low refractive index layer (SiO ₂ , 30 nm), a high refractive index layer (TiO ₂ , 100 nm). ) And a low refractive index layer (SiO ₂ , 100 nm) were formed in this order by sputtering. The obtained film was visually observed under a three-wavelength light region type fluorescent lamp, and interference unevenness was observed.

The polyester used in the examples and comparative examples was prepared as follows.
<Manufacture of polyester>
100 parts of dimethyl terephthalate, 60 parts of ethylene glycol and 0.09 part of magnesium acetate tetrahydrate are placed in a reactor, the temperature is raised by heating, methanol is distilled off, transesterification is performed, and 4 hours are required from the start of the reaction. The temperature was raised to 230 ° C. to substantially complete the transesterification reaction. Next, 0.04 part of ethyl acid phosphate, 0.03 part of antimony trioxide and 0.01 part of silica particles having an average particle diameter of 1.5 μm were added, and then the temperature reached 280 ° C. and the pressure reached 15 mmHg in 100 minutes. After that, the pressure was gradually reduced after that to finally reach 0.3 mmHg. After 4 hours, the system was returned to normal pressure to obtain polyethylene terephthalate having an intrinsic viscosity of 0.61.

Examples of compounds constituting the easy-adhesion layer are as follows.
(Compound example)
Compound having condensed polycyclic aromatic: (A) Water dispersion of polyester resin copolymerized with the following composition: Monomer composition: (acid component) 2,6-naphthalenedicarboxylic acid / isophthalic acid / 5-sodium sulfoisophthale Acid // (diol component) ethylene glycol / diethylene glycol = 84/13/3 // 80/20 (mol%)
-Organic compound having a metal element: (B1) Titanium triethanolamate-Organic compound having a metal element: (B2) Titanium lactate-Binder polymer: (C) A water dispersion of a polyester resin copolymerized with the following composition: Monomer composition : (Acid component) terephthalic acid / 5-sodiumsulfoisophthalic acid // (diol component) ethylene glycol / diethylene glycol = 92/8 // 77/23 (mol%)
・ Hexamethoxymethylmelamine: (D)
-Particles: (E) Silica sol with an average particle size of 65 nm

The produced polyethylene terephthalate was dried at 180 ° C. for 4 hours in an inert gas atmosphere, melted at 290 ° C. by a melt extruder, extruded from a die, and cooled by setting the surface temperature to 40 ° C. using an electrostatic application adhesion method. It cooled and solidified on the roll and the unstretched sheet was obtained. Next, the obtained unstretched sheet was first longitudinally stretched 3.6 times at 95 ° C., and the following coating agent was applied by a bar coating method. Stretching was performed. Then, it heat-set at 230 degreeC for 3 second, and obtained the 50-micrometer-thick polyester film in which the coating layer of the composition shown below whose coating amount (after drying) was 0.1 g / m < ² > was provided.

<< Coating layer composition >>
Compound having condensed polycyclic aromatic (A): 52% by weight
Binder polymer (C): 45% by weight
Silica sol having an average particle diameter of 65 nm (E): 3% by weight
The concentration of the coating solution was 10% by weight.

When the reflectance of the finished laminated polyester film was measured in the wavelength range of 350 to 800 nm, the minimum value was 4.5%. There was no interference unevenness after the antireflection layer was laminated, and the visibility was good. The properties of this antireflection film are shown in Table 1 below.
(Example 2 to Example 8)

  In Example 1, except having changed a coating agent composition into the coating agent composition shown in Table 1, it manufactured like Example 1 and obtained the laminated polyester film. As shown in Table 1, the finished laminated polyester film had high reflectance, no interference unevenness after the antireflection layer was laminated, and good visibility.

(Comparative Example 1)
In Example 1, except having changed a coating agent composition into the coating agent composition shown in Table 1, it manufactured like Example 1 and obtained the laminated polyester film. When the reflectance of the finished laminated polyester film was measured in the wavelength range of 350 to 800 nm, the minimum value was 3.7%. Interference unevenness occurred after the antireflection layer was laminated, and visibility was deteriorated. Table 1 shows the properties of the antireflection layer.

(Comparative Example 2)
In Example 1, except having changed a coating agent composition into the coating agent composition shown in Table 1, it manufactured like Example 1 and obtained the laminated polyester film. When the reflectance of the completed laminated polyester film was measured in the wavelength range of 350 to 800 nm, the minimum value was 3.6%. Interference unevenness occurred after the antireflection layer was laminated, and visibility was deteriorated. Table 1 shows the properties of the antireflection layer.

(Comparative Example 3)
In Example 1, except having changed a coating agent composition into the coating agent composition shown in Table 1, it manufactured like Example 1 and obtained the laminated polyester film. The finished laminated polyester film was poor in surface of the easy adhesion layer and could not be used as a polyester film for an antireflection film.

  The film of the present invention can be suitably used for, for example, LCDs, PDPs, organic ELs, and other optical applications for producing display members, and applications that place importance on visibility.

Claims (1)

A polyester film for an antireflection film, which is a polyester film having an easy-adhesion layer on at least one surface, and the easy-adhesion layer contains a compound having a condensed polycyclic aromatic.