JP2005313450A - Reflection preventing film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reflection preventing film which suppresses the generation of interference nonuniformity even when a hard coat layer is laminated on it and is excellent in moisture resistance. <P>SOLUTION: In the reflection preventing film, the hard coat layer and a reflection preventing layer are laminated in turn on one side of a biaxially oriented film of a polyester which contains 1,4-cyclohexane dicarboxylic acid derivative units and 1,4-cyclohexane dimethanol derivative units as repeating units as main components and has a melting point of at least 200°C. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an antireflection film, and in particular, relates to an antireflection film having little interference unevenness and excellent moisture resistance.

  In recent years, displays for consumer color televisions and personal computers have been increasing in size. In particular, color televisions are becoming widespread by replacing conventional cathode ray tube (CRT) televisions with thin, light and large screen plasma displays (PDPs) and liquid crystal televisions (LCDs).

  In general, in order to improve the visibility by reducing the reflection of external light such as sunlight or fluorescent lamps on the surface of the display screen, it is often necessary to perform an antireflection treatment. This antireflection treatment can be performed directly on the display screen. However, if the screen is large, it is inevitable that the processing apparatus will be enlarged. On the other hand, it has been proposed to attach an antireflection film that has been subjected to an antireflection treatment to the surface of the resin film in advance (for example, permissible documents 1 and 2). In particular, when the display screen is flat, this bonding method is simple and advantageous.

  By the way, although said resin film becomes a base material of an antireflection film, as this resin film, generally PET (polyethylene terephthalate) biaxially stretched film and TAC (triacetyl cellulose) film are used. These films are good in terms of transparency, flatness, mechanical properties, heat resistance, chemical resistance, etc., and have the advantage of versatility.

  In addition, in order to improve physical properties such as scratch resistance, heat resistance, and solvent resistance, an antireflection film is often provided with a hard coat layer, but there is a difference in refractive index between the hard coat layer and the resin film. If it is large, the light reflected at these boundary surfaces interferes and appears as interference unevenness. This phenomenon occurs remarkably when a PET film having a high refractive index is used as a base material.

  On the other hand, since the refractive index of the TAC film is not so high, the occurrence of interference unevenness when laminating the hard coat layer is small, but it has drawbacks in terms of water absorption and moisture resistance. There is a need for a resin film that is more suitable as a substrate.

JP 09-314757 A JP-A-11-174971

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an antireflection film that is less likely to cause interference unevenness even when a hard coat layer is laminated, and that is excellent in moisture resistance. is there.

  As a result of diligent study, the present inventor has found that, when a biaxially oriented polyester film made of an aliphatic polyester having a specific composition and physical properties is used as a base film of an antireflection film, the occurrence of interference unevenness is reduced and moisture resistance is reduced. In addition, the inventors have found that an excellent antireflection film can be obtained, and have completed the present invention.

  That is, the gist of the present invention consists of a polyester having, as a repeating unit, a unit derived from 1,4-cyclohexanedicarboxylic acid and a unit derived from 1,4-cyclohexanedimethanol as the main components and having a melting point of 200 ° C. or higher. The antireflection film is characterized in that a hard coat layer and an antireflection layer are sequentially laminated on one side of a biaxially oriented polyester film.

  The antireflection film of the present invention can improve visibility by suppressing reflection of external light such as sunlight and fluorescent lamps. Moreover, since the biaxially stretched film of aliphatic polyester is used for the base film, the transparency is good and the moisture resistance is excellent. For this reason, it is particularly useful as an antireflection film that is used by being attached to an image display surface of various displays, a show window, a vehicle window, or the like.

  Hereinafter, the present invention will be described in detail. However, the description of the constituent elements described below is a representative example of the embodiment of the present invention, and is not limited to these contents. The polyester film used as the base material of the antireflection film of the present invention is not an unstretched film or a film stretched only in a uniaxial direction, but is biaxially stretched sequentially or simultaneously in the longitudinal direction and the width direction, and then heat-set. It is necessary to be a biaxially oriented polyester film.

  The polyester which comprises a base film is a polycondensate which has as a main component the unit derived from 1, 4- cyclohexane dicarboxylic acid and the unit derived from 1, 4- cyclohexane dimethanol as a repeating unit. The main component as used herein means that the proportion of 1,4-cyclohexanedicarboxylic acid in the dicarboxylic acid component is usually 95 mol% or more, preferably 98 mol% or more, and that of 1,4-cyclohexanedimethanol in the diol component The ratio is usually 95 mol% or more, preferably 98 mol% or more.

  The proportion of the trans isomer of 1,4-cyclohexanedicarboxylic acid is usually 80 mol% or more, preferably 85 mol% or more, and the proportion of the trans isomer in 1,4-cyclohexanedimethanol is usually 60 mol%. Above, preferably 65 mol% or more.

  When the constituent ratio of the unit derived from the dicarboxylic acid component and the unit derived from the diol component does not satisfy the above range, the resulting polyester has a low melting point and often does not satisfy the following range defined in the present invention.

  Examples of other dicarboxylic acid components that can be used within the range of the constituent ratio of the unit derived from the dicarboxylic acid component and the unit derived from the diol component include, for example, cis 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexane. Aliphatic dicarboxylic acids such as dicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, oxalic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, and decanedicarboxylic acid. Examples of other diol components include cis 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,2-cyclohexanedimethanol, ethylene glycol, propylene glycol, butanediol, neopentyl glycol, Examples thereof include aliphatic diols such as pentanediol and hexanediol.

  In the present invention, for producing the polyester, for example, a conventionally known method of performing a polycondensation reaction after the ester reaction can be employed. The obtained polyester is extracted into water in the form of a strand and then pelletized.

  The polyester used as the base film needs to have a melting point of 200 ° C. or higher, a preferable melting point is 210 ° C. or higher, and the upper limit is usually 245 ° C. When the melting point is less than 200 ° C., the heat resistance of the polyester is insufficient, and the heat setting temperature after biaxial orientation cannot be set high. As a result, the shrinkage rate of the biaxially oriented polyester film increases, and when heated in post-processing, wrinkles, sagging, undulations, etc. occur and the flatness of the film deteriorates.

  Regarding the degree of polymerization of the polyester, the intrinsic viscosity measured at 30 ° C. in a mixed solvent of phenol-tetrachloroethane (weight ratio 1: 1) is usually 0.55 dl / g or more, preferably 0.65 dl / g or more. It is. By satisfying such conditions, it is possible to prevent continuity during film formation and a decrease in mechanical strength of the film formed. The upper limit of the intrinsic viscosity is usually 1.5 dl / g.

To the polyester used as the base film, fine particles that are substantially inert to the polyester can be added in order to impart slipperiness to the film and improve handling during processing. Specifically, such fine particles can be selected from particles made of an organic polymer such as a crosslinked polystyrene resin, a crosslinked acrylic resin, and a crosslinked polyester resin, and inorganic particles such as silica, talc, calcium carbonate, and calcium phosphate. These fine particles may be used alone or in combination of two or more. The upper limit of the average particle size of these fine particles is usually 4 μm, preferably 3 μm, and the lower limit is usually 0.05 μm, preferably 0.1 μm. . The upper limit of the amount added to the polyester is usually 1% by weight, preferably 0.5% by weight, and the lower limit is usually 0.005% by weight, preferably 0.01% by weight.

  In the antireflection film of the present invention, the biaxially oriented film used as a substrate may be a single layer film, but is a coextruded laminated film formed by laminating at least two layers, preferably three or more layers during melt extrusion. Is preferred. In particular, in the case of three or more layers, it is preferable to add the above-mentioned fine particles only to the surface layer and not add the fine particles to the intermediate layer, because the slipperiness can be improved without deteriorating the transparency. However, all the polyesters of each layer constituting these laminated films must satisfy the melting point range described above.

  In addition, known additives can be added to the polyester used for the base film without departing from the spirit of the present invention. Such additives include antioxidants, heat stabilizers, UV absorbers, colorants, infrared absorbers, antistatic agents, lubricants, flame retardants, and the like.

  In the antireflection film of the present invention, the film haze of the biaxially oriented polyester film used as the substrate is usually 5% or less, preferably 3% or less.

  Moreover, the thickness of the biaxially oriented polyester film is not particularly limited, but usually a film having a thickness in the range of 15 μm to 300 μm is frequently used.

  The base film used for the antireflection film of the present invention can be subjected to corona discharge treatment or primer layer coating on at least the surface on which the hard coat layer and the antireflection layer are laminated. This corona discharge treatment or coating of the primer layer is performed for the purpose of enhancing the adhesiveness between the biaxially oriented polyester film serving as the base material and the hard coat layer laminated thereon.

  The primer layer may be a coating layer applied to a film that has been biaxially oriented and heat-fixed to complete the crystal orientation, but the crystal orientation is completed in the film-forming process for producing the polyester film. A so-called in-line, in which one side or both sides of the polyester film before being subjected to a corona discharge treatment if necessary, after coating with a coating solution mainly using water as a medium, stretching in at least one direction, and further heat fixing The coating layer coated by the coating method is more preferable in terms of productivity and strong adhesion between the coating layer and the biaxially oriented polyester film.

  The primer layer preferably contains at least one of a polyurethane resin, a polyester resin, a poly (meth) acrylate resin, a polyvinyl resin, a modified body and a mixture thereof as a binder resin. In addition, these resins are usually dissolved in water to prepare a coating solution containing water as a main solvent when used in in-line coating in which the coating is performed within the film forming process, or In order to finely disperse, an anionic, cationic or amphoteric hydrophilic component is copolymerized in the molecule, or an aqueous dispersant is added.

  Moreover, you may use a crosslinking agent together for a primer layer. Specific examples of the crosslinking agent include methylolated or alkylolated urea compounds, melamine compounds, guanamine compounds, acrylamide compounds, polyamide compounds, epoxy compounds, oxazoline compounds, carbodiimide compounds, aziridine compounds, block poly An isocyanate, a silane coupling agent, a titanium coupling agent, a zirco-aluminate coupling agent, etc. are mentioned. These crosslinking components may be bonded in advance to the binder resin.

  Further, organic particles such as crosslinked polystyrene particles and inorganic particles such as silica particles may be added to the primer layer for the purpose of preventing sticking and improving slipperiness. The upper limit of the average particle diameter of these particles is usually 500 nm, preferably 100 nm, the lower limit is usually 5 nm, preferably 10 nm, and the content in the primer layer is usually 1 wt% or more and 10 wt% or less.

  As a coating method for forming the primer layer, for example, a reverse roll coater, a gravure coater, a rod coater, an air doctor coater, a die coater or the like can be used.

  The upper limit of the thickness of the coating layer as the primer layer is usually 500 nm, preferably 200 nm, and the lower limit is usually 10 nm, preferably 20 nm.

In addition, the following anionic or cationic antistatic agent is added to the primer layer, and the surface resistivity of the primer layer is 1 × 10 ¹² Ω or less, preferably 1 × 10 ¹¹ Ω. It is good also as follows.

  For example, as an anionic antistatic agent, metal salts or quaternary amine salts of alkyl sulfonic acids, metal salts or quaternary amine salts of alkyl benzene sulfonic acids, metal salts or quaternary amine salts of phosphate esters, metals of alkyl phosphate esters Salts or quaternary amine salts, polystyrene sulfonic acid metal salts or quaternary amine salts, monomers having a double bond capable of radical polymerization with styrene sulfonic acid (ethylene, styrene, acrylic acid, acrylic ester, methacrylic acid, methacrylic acid) Acid ester, vinyl chloride, vinyl acetate, vinyl ether, and the like) and metal salts or quaternary amine salts of oligomers.

  Examples of cationic antistatic agents include alkylammonium chloride, alkylbenzeneammonium chloride, and polymers containing either ionized nitrogen or pyrrolidinium rings in the main chain.

  Examples of the polymer containing a nitrogen atom ionized in the main chain include an ionene polymer. Specific examples of the compound include Japanese Patent Publication No. 53-23377, Japanese Patent Publication No. 54-10039, 47-34581, JP-A-56-76451, JP-A-58-93710, JP-A-61-18750, JP-A-63-68687, and the like. It is done.

  On the other hand, examples of specific compounds of a polymer containing a pyrrolidinium ring in the main chain include JP-A-1-146931, JP-A-1-166326, JP-A-1-171940, and JP-A-1-171985. And the compounds described in JP-A-1-174538, JP-A-1-174539 and the like.

  In the present invention, cationic polymer compounds are particularly preferably used from the viewpoint of antistatic performance.

  In addition to the above antistatic agent, alkylene glycol polymers such as polyethylene glycol and polytetramethylene glycol are used, and the upper limit of the weight average molecular weight is usually 2000, preferably 1000, and the lower limit is usually 100, preferably 500. I can do it. These alkylene glycol polymers are added for the purpose of decreasing the surface resistivity or reducing the humidity dependence of the antistatic performance.

  The content ratio of the antistatic agent and the binder resin in the primer layer is usually 1: 9 to 8: 2 (weight ratio).

  The antireflection film of the present invention is provided with a hard coat layer on one side of the above-mentioned base film or film provided with a primer layer in order to improve physical properties such as scratch resistance, heat resistance, and solvent resistance. is required.

  For the hard coat layer, a curable resin having good transparency such as urethane, alkyd, and epoxy resin can be used, but usually contains a polyacrylic acid derivative component or a polymethacrylic acid derivative component, and is heated. Resin that cures and cures by active energy ray treatment with UV treatment, ultraviolet rays, electron beam, etc. is suitable, especially from the viewpoint of surface hardness, durability, curability, etc. Resins are preferred.

  The hard coat layer is coated with a coating solution prepared from a curable resin monomer or oligomer, a reaction initiator, an additive, and a diluent (organic solvent) used as necessary, and then dried and cured. Can be applied after reaction. As the coating method, for example, a reverse roll coater, a gravure coater, a rod coater, an air doctor coater or the like can be used.

From the viewpoint of reducing interference unevenness, the upper limit of the refractive index of the hard coat layer is usually 1.57, preferably 1.56, and the lower limit is usually 1.49, preferably 1.50. The thickness of the hard coat layer is usually from 0.1 μm to 5 μm, and the hardness is usually from H to 5H as pencil hardness.
.

  The surface of the hard coat layer may be subjected to an anti-glare treatment in which fine irregularities are provided and light is irregularly reflected. As this treatment method, a method of directly forming irregularities on the hard coat surface, a method of dispersing fine particles in the hard coat layer, or the like can be used. The surface of the hard coat layer can be subjected to a corona discharge treatment in order to enhance the adhesion with the antireflection layer provided thereon.

  The antireflection film of the present invention needs to have an antireflection layer laminated on the hard coat surface of the hard coat film.

  The antireflection layer is usually an inorganic compound or an organic compound, and conventionally known ones can be used. These antireflection layers may be any of so-called dry coating thin films formed by vapor deposition or sputtering, or so-called wet coating thin films coated using a solvent, etc. In consideration, a wet coating thin film is preferable.

  Examples of the antireflection layer for forming a thin film by vapor deposition or sputtering include fluorides such as magnesium fluoride, calcium fluoride, and cerium fluoride, and oxides such as silicon oxide, titanium oxide, cerium oxide, aluminum oxide, and zirconium oxide. And a thin film formed of a sulfide such as zinc sulfide. These thin films may be a single layer film or a laminated film formed by stacking a plurality of thin films of different compounds.

  Examples of the antireflection layer to be coated using a solvent include a fluororesin and a partial hydrolyzate of silicon alkoxide.

  The fluororesin is preferably one that is excellent in transparency, has a refractive index of usually 1.44 or less, preferably 1.40 or less, and can be applied as a solution to a substrate. Specific examples of such a fluororesin include those described in JP-A-2-19811, JP-A-6-136062-4, JP-A-6-306326, JP-A-7-136552. I can list them.

  The above fluororesin uses, for example, a dip coating method, a roll coating method, a reverse roll coating method, a gravure coating method, a rod coating method, a spray coating method, a die coating method, etc. After coating, it can be dried to form a thin film to form an antireflection layer. Thereafter, the thin film can be further cured by irradiating the electron beam, ultraviolet rays, infrared rays or the like, or heating the thin film.

  Examples of the partial hydrolyzate of silicon alkoxide include those described in JP-A Nos. 2001-21701, 2002-286907 and the like.

  The above-mentioned antireflection layer is an outermost layer formed by partially hydrolyzing a silicon alkoxide such as tetraalkoxysilane or alkyltrialkoxysilane by adding an organic solvent such as alcohol, water, or an acid catalyst to a low refractive index layer. In this case, a metal oxide fine particle having a particle size of 1 nm to 100 nm is added to the partial hydrolyzate (binder) of this silicon alkoxide to provide conductivity, and a layer having a high refractive index is reflected. It can be used as an intermediate layer for the prevention layer. Examples of the metal oxide fine particles include indium oxide, tin oxide, titanium oxide, zirconium oxide, antimony-doped tin oxide, tin-doped indium, aluminum-doped zinc oxide, aluminum oxide, silicon oxide, antimony oxide, and tantalum oxide. used. And each said layer can be laminated | stacked by repeating application | coating and drying sequentially on a base film as a solution or a dispersion liquid, and these application | coating methods use the same method as the case of the above-mentioned fluororesin. I can do it.

  The film thickness of the antireflection layer needs to be determined by optical design depending on the refractive index of each layer, but in general, it is preferably in the range of 50 nm to 150 nm. Further, the minimum value of the reflectance of the surface on which the antireflection layer is present is usually 570 ± 100 nm, preferably 570 ± 50 nm, and as a result, the design of the visibility average reflectance is usually 3.0% or less, preferably Is set to 2.0% or less.

  The antireflection film prepared as described above can be bonded to a display screen, for example, by providing an adhesive layer on the surface opposite to the surface on which the antireflection layer is laminated.

  Conventionally known adhesives and pressure-sensitive adhesives can be used for the adhesive layer. Examples of adhesives and pressure-sensitive adhesives include compositions in which organic solvents, crosslinking agents, and tackifiers (rosin, polymerized rosin, modified terpene, etc.) are appropriately added to various resins. Rubber resins such as isoprene rubber, polyisobutylene rubber, styrene butadiene rubber, (meth) acrylate resin, polyvinyl ether resin, polyvinyl acetate resin, polyvinyl chloride vinyl acetate copolymer resin, polyvinyl butyral resin, silicone And synthetic resins mainly composed of resin, urethane resin, epoxy resin, melamine resin, phenol resin and the like. In addition, a colorant, an ultraviolet absorber, an infrared absorber, an antistatic agent and the like can be added to the adhesive layer as necessary.

  In the antireflection film of the present invention, a release film provided with a known release layer containing a silicone resin or a fluororesin may be laminated in order to protect the pressure-sensitive adhesive or adhesive.

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

1. Polyester melting point (Tm):
Using a differential scanning calorimeter (“DSC-2920” manufactured by TA Instruments), the temperature was measured at a rate of temperature increase of 20 ° C./min, and the temperature at the top of the endothermic peak accompanying crystal melting was taken as the melting point.

2. Average particle size of fine particles:
The equivalent spherical diameter of the particles at the 50% by weight point of all particles determined by the light scattering method was used as the average particle diameter.

3. Film haze value:
Using an integrating sphere turbidimeter (“NDH2000” manufactured by Nippon Denshoku Co., Ltd.), the haze value (%) was determined according to JIS K 7136 (2000) (equivalent to ISO 14782 1999).

4). Surface resistivity:
“16008B” (trade name) manufactured by Hewlett-Packard Japan, which is a concentric electrode having an inner electrode diameter of 50 mm and an outer electrode diameter of 70 mm, was used. A concentric electrode was placed on the sample in an atmosphere of 23 ° C. and 50% RH, a voltage of 100 V was applied, and the surface resistivity of the sample was measured with “4339B” (trade name), which is a high resistance meter of the company.

5. Pencil hardness:
The test sample was fixed with a cellophane tape on a glass plate having a thickness of 2 mm, and a scratch test of the coating film was performed with a pencil according to JIS K 5400 (1990). Judgment was evaluated by scratches on the coating film.

6). Visibility average reflectance and minimum reflectance wavelength:
Using a spectrophotometer equipped with a 5 ° absolute specular reflectance measuring device and a multipurpose large sample chamber unit (“UV-3100PC” and “MPC-3100” manufactured by Shimadzu Corporation), the absolute reflectance was measured. The measurement was performed from the antireflection surface side, and the opposite surface was uniformly roughened with sandpaper and then painted with black paint. The reflection wavelength spectrum was obtained by setting the measurement wavelength range to 380 to 780 nm. From this reflection spectrum, the visibility average reflectance for the D65 light source defined in JIS Z 8720 (2000) was calculated. Further, the wavelength of light showing the minimum reflectance was read in units of 10 nm from the reflection spectrum. When the interference was large, the center was read.

7). Interference unevenness evaluation:
Interference unevenness was visually observed under a three-wavelength fluorescent lamp.

8). Moisture resistance:
The test sample was allowed to stand for 1000 hours in a constant temperature and humidity chamber maintained in an atmosphere of 60 ° C. and 90% RH, and the appearance was compared with a sample stored in an atmosphere of 23 ° C. and 50% RH.

9. Refractive index of coating film:
Measurement was performed using a refractometer “T-2 type” manufactured by Atago Co., Ltd. and using a D-line of a sodium lamp as a light source. The temperature during measurement was 23 ° C. For the coating layer, a plastic film having releasability with respect to it was selected, coated thereon, and measured using a peeled film.

Example 1:
<Creation of polyester raw material A>
In a reactor equipped with a stirrer, a distillation tube and a pressure reducing device, 184 parts by weight of 1,4-cyclohexanedicarboxylic acid (1,4-CHDA) (trans isomer 98%) and 1,4-cyclohexanedimethanol (1,4 -CHDM) (67% trans isomer) 158 parts by weight, 0.9 part by weight of a 6% by weight butanol solution of Ti (OC ₄ H ₉ ) ₄ was heated to 150 ° C. under a nitrogen stream, and then 1 to 200 ° C. The temperature was raised over time. Thereafter, the esterification reaction was carried out by maintaining at 200 ° C. for 1 hour, and then the polycondensation reaction was carried out while gradually raising the pressure in the reactor from 200 ° C. to 250 ° C. over 45 minutes. After polymerization for 2 hours at an absolute pressure of 0.1 kPa and a reaction temperature of 250 ° C. in the reactor, the obtained polymer was drawn into water as a strand and then pelletized. The intrinsic viscosity of this polyester was 0.85 dl / g. The melting point was 220 ° C.

<Creation of polyester raw material B>
Polyester raw material A is dry-blended with 0.5% by weight of divinylbenzene crosslinked polystyrene particles with an average particle size of 1.1μm, and then put into a twin screw extruder with a vent to remove moisture at a vacuum of 1kPa absolute pressure. The mixture was melted and mixed, extracted into water as a strand, and then pelletized. The intrinsic viscosity of this polyester was 0.82 dl / g. The melting point was 220 ° C.

<Made of polyester film>
Polyester A and polyester B were mixed at a weight ratio of 9: 1 and charged into a surface layer extruder. Separately from this, only polyester A was fed into an extruder for the intermediate layer. Each extruder is a twin-screw extruder with a vent, the resin is used without drying, and extrusion is performed at a melting temperature of 250 ° C. while removing moisture from the vent port at a vacuum of 1 kPa absolute pressure. It was. Each extruder is equipped with a gear pump and a filter. The melted polymer that has passed through them is merged and laminated in the feed block and melt-extruded from the T-die. Created a sheet. At this time, the thicknesses of both surface layers were the same, and the total thickness of both surface layers was set to be 6% of the total thickness. At this time, the film was cast on a cooling drum at 20 ° C. by applying an electrostatic application adhesion method.

  The obtained unstretched sheet was led to a longitudinal stretching process. For the longitudinal stretching, a roll stretching method was used. Preheating was performed at 70 ° C. with a plurality of rolls, and further, an IR heater was used in combination for stretching in the longitudinal direction at a stretching ratio of 3.0. Next, this uniaxially stretched film was guided to a tenter, preheated at 85 ° C., and then stretched in the width direction at a stretch ratio of 3.8 times. Thereafter, the film was heat-set at 185 ° C. under tension in the same tenter to obtain a biaxially oriented polyester film having a total thickness of 100 μm. The haze value of this polyester film was 1.0%.

<Lamination of hard coat layer>
After applying a corona discharge treatment to one side of the biaxially oriented polyester prepared by the above method, an acrylic hard coat agent (“KAYANOVA” manufactured by Nippon Kayaku Co., Ltd.) is used with a mixed solvent of toluene and methyl ethyl ketone (weight ratio 1: 1). FOP-1700 ": The refractive index after drying and curing was diluted 1.54), and was applied by a reverse gravure coating method so that the coating thickness after drying and curing was 3 μm. Next, the solvent was removed by drying at 110 ° C. for 1 minute, and then UV curing was performed with a high pressure mercury lamp under the conditions of an output of 120 w / cm, an irradiation distance of 15 cm, and a moving speed of 10 m / min to form a hard coat layer. The pencil hardness of the hard coat layer surface was 2H.

<Lamination of antireflection layer>
35 g of perfluorobutenyl vinyl ether, 5 g of 1,1,2-trichloro1,2,2-trifluoroethane, 150 g of ion-exchanged water, 90 mg of ((CH ₃ ) ₂ CHOCOO) ₂ as a polymerization initiator are made of pressure-resistant glass The autoclave was charged. After the system was purged with nitrogen, suspension polymerization was carried out at 40 ° C. for 22 hours. As a result, 28 g of transparent fluororesin was obtained. The refractive index of this fluororesin was 1.34. This fluororesin was dissolved in perfluoro (2-butyltetrahydrofuran) to prepare a solution. Subsequently, after the corona discharge treatment is applied to the hard coat surface of the above hard coat film, a “micro gravure coater” (manufactured by Yasui Seiki Co., Ltd.) is used so that the coating thickness after drying becomes 100 nm. After coating the above solution, the coating was dried at 120 ° C. for 10 minutes to laminate an antireflection layer.

  The above-mentioned antireflection film had a visual sensitivity average reflectance of 0.7%, was excellent in antireflection performance, and was excellent in that interference unevenness was hardly seen. Furthermore, this antireflection film was good with no change in film appearance in a 1000 hour humidity resistance test.

Example 2:
<Made of polyester film>
The same polyester raw material as in Example 1 was used, and melt extrusion, casting, and longitudinal stretching were performed in exactly the same manner as in Example 1. After performing corona discharge treatment on both surfaces of this uniaxially stretched film, a coating solution using water as a medium shown in the following primer layer composition 1 is applied to both surfaces of the film in a final biaxially oriented film coating amount of 0 respectively. It was applied by a bar coating method so as to be 0.09 μm. Next, this uniaxially stretched film was guided to a tenter, dried at 90 ° C. and preheated, and then stretched in the width direction at a stretch ratio of 3.8 times. Thereafter, heat setting was performed at 185 ° C. under tension in the same tenter to obtain a biaxially oriented polyester film having a total thickness of 100 μm. The surface specific resistance value of the primer layer of this film was 1 × 10 ¹⁰ Ω.

<Lamination of hard coat layer>
A hard coat layer was formed on one side of the biaxially oriented polyester prepared above in the same manner as in Example 1 except that the corona discharge treatment was not performed.

<Lamination of antireflection layer>
An antireflection layer was laminated in exactly the same manner as in Example 1. The obtained antireflection film had an average reflectance of 0.7%, was excellent in antireflection performance, and the appearance of uneven interference was thin and acceptable. Further, in the 1000 hour humidity resistance test of this antireflection film, the film appearance was unchanged and good.

Comparative Example 1:
<Creation of polyester raw material C>
In the production of the polyester raw material A of Example 1, polyester raw material A was used except that 1,4-cyclohexanedicarboxylic acid (trans isomer 98%) was used instead of 1,4-cyclohexanedicarboxylic acid (trans isomer 98%). Polymerization was carried out in exactly the same manner as in production to prepare polyester raw material C. This polyester had an intrinsic viscosity of 0.84 dl / g. The melting point was 192 ° C.

<Creation of polyester raw material D>
Polyester raw material C is dry blended with 0.5% by weight of divinylbenzene cross-linked polystyrene particles having an average particle size of 1.1 μm, and is put into a twin screw extruder with a vent. While being removed, the mixture was melt-mixed, extracted into water as a strand, and then pelletized. The intrinsic viscosity of this polyester was 0.81 dl / g. The melting point was 192 ° C.

<Made of polyester film>
Polyester C and polyester D were mixed at a weight ratio of 9: 1 and charged into a surface layer extruder. Separately from this, only the polyester C was put into the extruder for the intermediate layer. Thereafter, in the same manner as in Example 1, melt extrusion, casting, longitudinal stretching, and transverse stretching were performed. Then, heat setting was performed at 150 ° C. under tension in the same tenter to obtain a biaxially oriented polyester film having a total thickness of 100 μm.

<Lamination of hard coat layer>
A hard coat layer was formed in exactly the same manner as in Example 1, but the shrinkage of the film during drying was large and the flatness deteriorated.

<Lamination of antireflection layer>
Lamination of the antireflection layer was attempted in exactly the same manner as in Example 1, but the antireflection layer could not be uniformly laminated because of the poor flatness of the hard coat film.

Comparative Example 2:
<Polyester raw material E>
Polyethylene terephthalate melt polymerized according to a conventional method (inherent viscosity 0.71 dl / g, melting point 256 ° C.).

<Polyester raw material F>
Polyester raw material E is dry-blended with 0.5% divinylbenzene crosslinked polystyrene particles with an average particle size of 1.1 μm, and put into a twin-screw extruder with a vent to keep moisture at an absolute pressure of 1 kPa. While being removed, the mixture was melt-mixed, extracted into water as a strand, and then pelletized. This polyester had an intrinsic viscosity of 0.68 dl / g. The melting point was 256 ° C.

<Made of polyester film>
Polyester E and polyester F were mixed at a weight ratio of 9: 1 and charged into a surface layer extruder. Separately from this, only polyester E was charged into the extruder for the intermediate layer. Thereafter, the melting temperature is 280 ° C., the longitudinal stretching temperature is 83 ° C., the longitudinal stretching ratio is 3.5 times, the transverse stretching temperature is 100 ° C., the transverse stretching ratio is 3.8 times, and the heat setting temperature is 220 ° C. Except for this, melt extrusion was performed in the same manner as in Example 1, and longitudinal stretching, lateral stretching, and heat setting were performed to obtain a biaxially oriented polyester film having a total thickness of 100 μm. The haze value of this film was 1.0%.

<Lamination of hard coat layer>
A hard coat layer was formed in exactly the same manner as in Example 1.

<Lamination of antireflection layer>
An antireflection layer was laminated in exactly the same manner as in Example 1. The obtained antireflection film had an average reflectance of 0.8% and was excellent in antireflection performance, but the interference unevenness was clear and conspicuous. Further, in the 1000 hour humidity resistance test of this antireflection film, the film appearance was unchanged and good.

Comparative Example 3:
As the base film, an 80 μm triacetyl cellulose film (“Fujitac UV80” manufactured by Fuji Film Co., Ltd.) was used.

<Lamination of hard coat layer>
A hard coat layer was formed in exactly the same manner as in Example 1.

<Lamination of antireflection layer>
An antireflection layer was laminated in exactly the same manner as in Example 1. The obtained antireflection film had an average reflectance of 0.7%, was excellent in antireflection performance, and the appearance of uneven interference was thin and acceptable. However, in the 1000-hour moisture resistance test of this antireflection film, the flatness that seems to be caused by moisture absorption of the base film was deteriorated.

Claims (1)

  As a repeating unit, on one side of a biaxially oriented polyester film comprising a unit derived from 1,4-cyclohexanedicarboxylic acid and a unit derived from 1,4-cyclohexanedimethanol, the melting point of which is 200 ° C. or higher. An antireflection film, wherein a hard coat layer and an antireflection layer are sequentially laminated.