JP5732786B2 - Method for producing optical polyester film - Google Patents

Description

  The present invention relates to an optical polyester film having antistatic properties that are not dependent on humidity and excellent scratch resistance, and having a coating layer with less thickness unevenness and good appearance. Furthermore, an optical polyester that can be suitably used for an anti-reflective, near-infrared concealing, color tone correcting function used in plasma displays and liquid crystal display panels, or a polarizer protective film and a touch panel surface protective film. Related to film.

  Polyester films have excellent dimensional stability, mechanical properties, transparency, electrical properties, etc., so liquid crystal displays (LCDs) and plasma display panels (PDPs) used in televisions and mobile phones It is widely used as a base film for many applications such as display devices, magnetic tapes, and magnetic recording materials such as prepaid cards. Among them, the demand for polyester films used for display devices has been growing rapidly as the switching from so-called CRT televisions to thin televisions such as LCDs and PDPs is remarkable.

  PDP optical filters that use polyester film include electromagnetic waves that affect the human body and other electrical devices that leak from the PDP, near-infrared shielding that affects the remote control, and the surface of external light such as sunlight and fluorescent lights. A polyester film provided with functions such as surface reflection prevention for preventing reflection and reflection on the film is laminated. These optical filters have strict requirements for defects such as scratches, foreign matter, and unevenness, in addition to transparency and adhesion to the functional layer, and in recent years, in particular, the adhesion of foreign matter due to charging during the manufacture of optical filters and display panels. It is required to prevent this. In addition, the antistatic layer used for optical filters should exhibit antistatic properties stably in any environment, the surface should not be scratched when wiped off (good scratch resistance), coating Therefore, it has been required to provide an antistatic layer having these characteristics and appearance.

  As a typical method for imparting antistatic properties to a polyester film, there is a method of applying a formulation to which an ion conductive type antistatic agent such as a styrene sulfonic acid copolymer is added (Patent Document 1). These methods are dependent on humidity because they use a conductive mechanism that depends on the adsorption of moisture in the air by ions. Especially when low molecular weight type antistatic agents are used, the humidity dependence is large, so there is a large variation in antistatic properties depending on the environment, and antistatic properties can not be obtained at all in low humidity environments such as winter, There were major problems in product quality, such as poor scratch resistance of the coating film. Further, as a method of providing a polyaniline-based conductive agent layer on the surface of a polyester film, there is a method using a polyaniline-based conductive agent which is an electron conduction type antistatic agent (Patent Document 2). Since the conductive mechanism is based on conjugated electrons, there is no humidity dependency. However, since the doped state of the polyaniline antistatic agent is green, it is not preferable as an optical film in terms of product appearance. Moreover, the method of providing a layer of an antimony-doped tin oxide-based conductive agent on the surface of the polyester film is an antistatic method using an electron conductive type antistatic agent, and exhibits antistatic properties that are not dependent on humidity. The tin oxide antistatic agent requires a doping agent due to a harmful heavy metal such as antimony (Patent Document 3). Furthermore, particulate antistatic agents, typified by tin oxide antistatic agents, have no stretch-following properties when applied to an in-line coating method in which they are applied, stretched, and heat-treated in the film-forming process. Cracks occur in the film, and the coating film becomes white, or the coating film becomes brittle, so that there are problems such as lack of transparency and scratch resistance. Further, since the polythiophene antistatic agent is also an electron conduction type antistatic agent, it exhibits antistatic properties independent of humidity (Patent Document 4). Furthermore, as a method using a polythiophene antistatic agent, a method for obtaining a polyester film having excellent antistatic properties is disclosed (Patent Document 5).

JP-A-61-204240 JP-A-7-101016 Japanese Patent Laid-Open No. 11-278582 JP-A-9-31222 JP 2004-58648 A

  However, in the technique using the above polythiophene antistatic agent, the coating viscosity of the polythiophene antistatic agent is generally high, so that the coating layer obtained by coating has a large thickness unevenness, the reflected light wavelength and the reflection light Since the unevenness of the rate becomes large, the appearance is poor and unsuitable for optical uses such as an optical filter, and there is also a problem with the scratch resistance when the base film is smoothed to obtain transparency.

  The object of the present invention is to focus on the problems of the prior art described above, not only exhibiting a high level of antistatic property regardless of humidity change, but also highly transparent and excellent in scratch resistance, and less uneven coating thickness. It is to provide an optical polyester film having a good appearance and suitable for optical applications.

The optical polyester film of the present invention has the following constitution.
(1) A laminated polyester in which a coating layer (B layer) is laminated on at least one side of a base polyester film (A layer) by a metalling wire bar coating method in which a metalling wire bar and a cover are provided upstream and downstream thereof. This is a film manufacturing method , in which the gap (a) between the metalling wire bar and the upstream cover is 0.7 to 2.0 mm, and the gap (b) between the metalling wire bar and the downstream cover is narrower than (a). A method for producing an optical polyester film satisfying the following (a) to (b) :
(A) The specific resistance values of the surface on the B layer side at a temperature of 25 ° C. and a relative humidity of 65% RH and at a temperature of 25 ° C. and a relative humidity of 30% RH are both 10 ¹⁰ Ω / □ or less.
(B) In the section having a width of 1 m and a length of 1 m, with respect to the surface reflectance at a wavelength of 350 to 800 nm on the B layer side surface measured at a total of 25 points at intervals of 250 mm in the width direction and at intervals of 250 mm in the longitudinal direction, the reflectance is minimum. Where λmin is the wavelength and Rmin is the reflectance at λmin, the difference between the maximum and minimum values of λmin at the 25 measurement points is 30 nm or less, and the difference between the maximum and minimum values of Rmin is 0.5% or less. There is.
(2) The manufacturing method of the optical polyester film as described in (1) whose said clearance gap (b) is 0.3-0.7 mm.
( 3 ) The polyester film for optics according to (1) or (2) , wherein the substrate polyester film (A layer) contains substantially no particles and has a haze value of 1.0% or less . Manufacturing method .
( 4 ) The method for producing an optical polyester film according to any one of (1) to (3), wherein the thickness (L) of the coating layer (B layer) is 10 nm to 30 nm.
( 5 ) The coating layer (B layer) contains particles having an average particle diameter (d (nm)) and a coating layer (B layer) thickness (L (nm)) satisfying the following formula ( 1) to ( 4 ) The manufacturing method of the polyester film for optics in any one.

0.5 ≦ d / L ≦ 3.0
( 6 ) The manufacturing method of the polyester film for optics in any one of (1)-( 5 ) in which an application layer (B layer) contains polythiophene.
( 7 ) The coating layer (B layer) contains any one of a composition composed of polythiophene and polyanion, or a composition composed of a polythiophene derivative and polyanion, and an epoxy resin (1) to (5) The manufacturing method of the polyester film for optics in any one.
( 8 ) The optical polyester film according to any one of (1) to ( 7 ), wherein the base polyester film (A layer) contains an ultraviolet absorber and the transmittance at a wavelength of 380 nm is 5% or less . Manufacturing method .
(9) Coating fabric layer (B layer) is provided in the polyester film forming step, and at 25 ° C. of the coating layer (B layer) formed to the coating liquid, viscosity of 1 to 10 mPa · s, the frequency 2~5Hz The method for producing an optical polyester film according to any one of (1) to (8), wherein the dynamic surface tension is 30 to 60 mN / m.
(10) The production of the optical polyester film according to (9), wherein the coating liquid contains a surfactant and the blending amount thereof is 0.08 to 5% by mass with respect to 100% by mass of the coating liquid. Method.

  According to the present invention, it is possible to obtain an optical polyester film that exhibits a high level of antistatic properties regardless of humidity changes, has good transparency and scratch resistance, has a uniform coating thickness, and good appearance characteristics. Can do. In addition, the optical polyester film of the present invention is an optical polyester film that is difficult to get dust and not easily scratched even when the dust is wiped off, and has a very good appearance with reduced reflection light wavelength and reflectance unevenness. It is a film and can be suitably used as an optical member such as an optical filter for PDP. Moreover, even if a hard coat layer is provided on the coated layer side of the polyester film, it has no anti-humidity and has high antistatic properties, so that it can be used as a polarizer protective film, a surface protective film for touch panels, or an electrode film for touch panels. Can also be suitably used.

It is the schematic of the coating device by the metaling wire bar which concerns on one embodiment of the polyester film for optics of this invention. FIG. 2 is an enlarged view of a metering wire bar portion of FIG. 1. It is the schematic of the coating device by the metaling wire bar which concerns on one embodiment of the polyester film for optics of this invention. FIG. 4 is an enlarged view of a metering wire bar portion of FIG. 3. It is the structure schematic diagram at the time of use for the touch-panel member which concerns on one embodiment of the polyester film for optics of this invention. It is the structure schematic at the time of use for the polarizing plate member which concerns on one embodiment of the polyester film for optics of this invention.

  The configuration of the optical polyester film of the present invention is a laminated polyester film in which a coating layer (B layer) is laminated on at least one surface of a base polyester film (A layer).

  The polyester used for the base polyester film (A layer) of the optical polyester film of the present invention is ethylene terephthalate, propylene terephthalate, ethylene-2,6-naphthalate, butylene terephthalate, propylene-2,6-naphthalate, ethylene-α. , Β-bis (2-chlorophenoxy) ethane-4,4′-dicarboxylate and the like, those having at least one component selected as a main component can be preferably used. These constituent components may be used alone or in combination of two or more. Among these, polyesters having ethylene terephthalate as a main constituent, that is, polyethylene terephthalate, in view of quality, economy, etc. It is particularly preferable to use When heat or shrinkage stress acts on the base film, polyethylene-2,6-naphthalate having excellent heat resistance and rigidity is more preferable. These polyesters may further be partially copolymerized with other dicarboxylic acid components and diol components, preferably 20 mol% or less.

  In the present invention, various additives such as an antioxidant, a heat stabilizer, a weather stabilizer, an ultraviolet absorber, a pigment, a dye, a filler, an antistatic agent, and a nucleating agent are contained in the base polyester film (A layer). May be added to such an extent that the characteristics are not deteriorated. In particular, the transmittance at 380 nm is preferably 5% or less, and more preferably 3% or less, in order to prevent deterioration of the functional layer described later due to ultraviolet rays. In order to impart such UV-cutting ability, it is preferable to contain a UV absorber in the polyester film (A layer). Examples of UV absorbers used include salicylic acid compounds, benzophenone compounds, benzotriazole compounds, Preferred examples include cyanoacrylate compounds, benzoxazinone compounds, cyclic imino ester compounds, and the like, but the UV cut ability at 380 nm, color tone, and the polyester M + P, M / P (M Is the concentration of the catalytic metal element remaining in the film (mmol%), P is the concentration of the phosphorus element remaining in the film (mmol%).) Dinone compounds are most preferred. These compounds can be used alone or in combination of two or more. In addition, stabilizers such as HALS and antioxidants can be used in combination, and it is particularly preferable to use a phosphorus-based antioxidant in combination.

  Here, as the benzotriazole-based compound, for example, 2- (2H-benzotriazol-2-yl) 4,6-bis (1-methyl-1-phenylethyl) phenol, 2- (2H-benzotriazole-2) -Yl) -4- (1,1,3,3-tetramethylbutyl) phenol, 2- (2H-benzotriazol-2-yl) -4-methylphenol, 2- (2H-benzotriazol-2-yl) ) -4,6-di-t-butylphenol, 2- (2H-benzotriazol-2-yl) -4,6-di-t-amylphenol, 2- (2H-benzotriazol-2-yl) 4- t-butylphenol, 2- (2'-hydroxy-3'-t-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2'-hydro Shi -3 ', 5' - can be exemplified di -t- butyl phenyl) -5-chloro-benzotriazole, or the like.

  Examples of the benzophenone compounds include 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,2′-dihydroxy-4,4′-dimethoxybenzophenone, 2,2,2 ′, 4,4 ′. -Tetrahydroxybenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid and the like can be mentioned.

  Examples of the benzoxazinone compound include 2-p-nitrophenyl-3,1-benzoxazin-4-one, 2- (p-benzoylphenyl) -3,1-benzoxazin-4-one, 2- ( 2-naphthyl) -3,1-benzoxazin-4-one, 2,2′-p-phenylenebis (3,1-benzoxazin-4-one), 2,2 ′-(2,6-naphthylene) Bis (3,1-benzoxazin-4-one) and the like can be exemplified.

  The intrinsic viscosity (measured in o-chlorophenol at 25 ° C.) of the polyester film (A layer) is preferably 0.4 to 1.2 dl / g, more preferably 0.5 to 0.8 dl / g. This is suitable for carrying out the present invention.

  The polyester film (A layer) is preferably biaxially oriented. A biaxially oriented polyester film is generally an unstretched polyester sheet or film that is stretched about 2.5 to 5 times in the longitudinal direction and in the width direction, and then subjected to heat treatment to complete crystal orientation. It is a thing which shows a biaxially oriented pattern by wide-angle X-ray diffraction.

  Further, the base polyester film (A layer) used in the present invention may be a laminated structure in which the A layer itself is two or more layers. As the laminated structure, for example, a composite film having an inner layer portion and a surface layer portion, which is substantially free of particles in the inner layer portion, and provided with a layer containing particles in the surface layer portion. The inner layer portion and the surface layer portion may be chemically different polymers or the same type of polymers. In the main display application of the optical polyester film of the present invention, it is preferable from the viewpoint of optical properties such as transparency that the inner layer portion does not contain particles.

  The haze of the optical polyester film of the present invention is 1.0% or less. If it is larger than 1.0%, the scattering of transmitted light becomes large and the transparency is inferior, so that the appearance is deteriorated and the inspection properties such as defects are inferior, and it is not suitable as an optical member. Therefore, from the viewpoint of haze and transparency, it is desirable that the base polyester film (A layer) does not substantially contain particles.

  The layer thickness of the base polyester film (A layer) is not particularly limited and is appropriately selected depending on the application, but is usually 10 to 500 μm, preferably 20 to 300 μm, more preferably 50 to 250 μm.

  In the optical polyester film of the present invention, the coating layer (B layer) having antistatic properties is laminated on at least one surface of the base polyester film (A layer). Necessary for preventing damage to parts.

  The coating liquid used for the coating layer (B layer) of the optical polyester film of the present invention is preferably an aqueous coating liquid containing water as a main medium. The coating liquid may contain an appropriate amount of an organic solvent to the extent that it does not impair the effects of the optical polyester film of the present invention, for the purpose of improving coating properties and transparency. For example, isopropyl alcohol, t-butyl cellosolve, n-butyl cellosolve, ethyl cellosolve, acetone, N-methyl-2-pyrrolidone, ethanol, methanol and the like can be suitably used. Among them, it is particularly preferable to use isopropyl alcohol from the viewpoint of improving the coating property, and the content thereof is preferably 20% by mass or less, more preferably 10% by mass or less in the coating liquid. In addition, when a large amount of an organic solvent is contained in the coating liquid, there is a risk of explosion in a tenter that performs preheating, drying, stretching, and heat treatment steps when applied to a so-called in-line coating method, which is not preferable.

The surface specific resistance of the surface on the coating layer (B layer) side is 10 ¹⁰ Ω / □ or less at both temperature 25 ° C. and relative humidity 65% RH and temperature 25 ° C. and relative humidity 30% RH, preferably It is 10 ⁸ Ω / □ or less, and it is necessary to develop a high level of antistatic property regardless of humidity change. In any one of the above environments, when the surface specific resistance value is larger than 10 ¹⁰ Ω / □, there is a problem that dust is likely to adhere, defective products are generated, and inspection efficiency is deteriorated. The lower limit of the surface specific resistance value is not particularly limited, but is usually about 10 ⁴ Ω / □.

  Examples of the antistatic agent satisfying such characteristics include a compound having a quaternary ammonium base that is a cationic conductor, a polyaniline-based conductive agent that is a conjugated electronic conductor, a tin oxide-based conductive agent, a polythiophene-based conductive agent, and the like. Is mentioned. An anionic conductive pair having a sulfonic acid group or the like that is generally widely used is not preferable because the antistatic performance changes greatly due to humidity and the water resistance is poor. When a compound having a quaternary ammonium base which is a cationic conductor is used, it can be used because the change in antistatic performance due to humidity is relatively small and the water resistance is relatively strong. On the other hand, when a polyaniline-based conductive agent, tin oxide-based conductive agent, or polythiophene-based conductive agent, which is a conjugated electron conductor, is used, the amount of change in antistatic performance due to humidity because the electronic conductive mechanism does not depend on moisture in the air. Is very small and suitable. Of these, polythiophene and polythiophene derivatives are particularly preferred because they are excellent in transparency of the coating film, adhesion to the base polyester film, and coating appearance.

The compound having a quaternary ammonium base which is a cationic conductor is a compound having a component containing a quaternary ammonium base in the main chain or side chain of the molecular chain. Examples thereof include quaternary compounds of alkylamines, those obtained by copolymerizing these with acrylic acid or methacrylic acid, quaternary compounds of N-alkylaminoacrylamide, and vinylbenzyltrimethylammonium salt. Examples of the anion serving as a counter ion for the quaternary ammonium base include halogen, alkyl sulfate, alkyl sulfonate, and nitric acid. The compound having a quaternary ammonium base is preferably a polymer compound. If the molecular weight is too low, the antistatic agent may be transferred from the surface of the antistatic layer to the reverse side, or to a roll or mold in the process, which may cause adhesion failure on the reverse side or a product defect. Therefore, it is not preferable. The number average molecular weight of the compound having a quaternary ammonium base is preferably 2000 or more, more preferably 5000 or more. In addition, if the molecular weight is too large, the viscosity of the coating solution becomes too high, or the followability at the time of stretching deteriorates. Therefore, the number average molecular weight is preferably 100,000 or less.
The polythiophene and polythiophene derivative, which are conjugated electron conductors, can be obtained, for example, by polymerizing a compound represented by the following chemical formula (1) or the following chemical formula (2) in the presence of a polyanion. In the chemical formula (1), R 1 and R 2 each independently represent a hydrogen element, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group, or an aromatic hydrocarbon group, such as a methyl group, Examples thereof include an ethyl group, a propyl group, an isopropyl group, a butyl group, a cyclohexylene group, and a benzene group. In the chemical formula (2), n is an integer of 1 to 4.

  In the optical polyester film of the present invention, it is preferable to use a polythiophene having a structural formula represented by the chemical formula (2) or a polythiophene derivative. For example, in the chemical formula (2), n = 1 (methylene group), n = A compound of 2 (ethylene group) and n = 3 (propylene group) is preferable. Among them, particularly preferable is an ethylene group compound of n = 2, that is, poly-3,4-ethylenedioxythiophene. Examples of polythiophene or polythiophene derivatives include compounds in which a functional group is bonded to positions 3 and 4 of the thiophene ring. As described above, a compound in which an oxygen atom is bonded to the 3rd and 4th carbon atoms is preferable. For a compound having a structure in which a carbon atom or a hydrogen atom is directly bonded to the carbon atom, it may not be easy to make the coating liquid aqueous.

  In the optical polyester film of the present invention, the antistatic treatment layer preferably contains a composition comprising the polythiophene and a polyanion or a composition comprising the polythiophene derivative and a polyanion. The poly anion of the optical polyester film of the present invention is an acidic polymer in a free acid state, such as a high molecular carboxylic acid, a high molecular sulfonic acid, or a polyvinyl sulfonic acid. Examples of the polymer carboxylic acid include polyacrylic acid, polymethacrylic acid, and polymaleic acid. Examples of the polymer sulfonic acid include polystyrene sulfonic acid. In particular, polystyrene sulfonic acid is electrically conductive. Most preferred. In the optical polyester film of the present invention, the free acid is obtained by using a polythiophene compound that is originally insoluble in water by using these polyanions, which may be in the form of partially neutralized salts, during polymerization. It is easy to disperse or form an aqueous solution, and it is considered that the function as an acid also functions as a dopant for the polythiophene compound. In the optical polyester film of the present invention, the polymer carboxylic acid or polymer sulfonic acid is used in a form copolymerized with other copolymerizable monomers such as acrylic acid ester, methacrylic acid ester, and styrene. You can also.

The molecular weight of the polymer carboxylic acid or polymer sulfonic acid used as the polyanion is not particularly limited, but the mass average molecular weight is preferably 1,000 to 1,000,000, more preferably 5,000, from the viewpoint of coating stability and conductivity. ~ 150,000. As long as the properties of the optical polyester film of the present invention are not impaired, an alkali salt such as a lithium salt or a sodium salt, an ammonium salt, or the like may be partially included. Even in the case of neutralized salts, polystyrene sulfonic acid and ammonium salts, which function as very strong acids, are known to shift to the acidic side due to the progress of the equilibrium reaction after neutralization. In the optical polyester film of the present invention, it is preferable from the viewpoint of conductivity that the polyanion is excessively present at a solid content mass ratio with respect to polythiophene or a polythiophene derivative. The amount of polyanion is more than 1 part by mass, preferably 5 parts by mass or less, more preferably more than 1 part by mass and 3 parts by mass or less with respect to 1 part by mass of polythiophene and / or polythiophene derivative. Of course, other components may be used as long as the effects of the optical polyester film of the present invention are not impaired.

  The composition comprising the above polythiophene or polythiophene derivative and polyanion is disclosed in, for example, JP-A-6-295016, JP-A-7-292081, JP-A-1-313521, JP-A-2000-6324. , European Patent No. 602713, US Pat. No. 5,391,472 and the like, but other methods may be used. For example, as an aqueous coating liquid of a composite composed of poly-3,4-ethylenedioxythiophene / polystyrene sulfonic acid, Bayer / H. C. A product sold as “Baytron” P from Starck (Germany) can be used.

  The composition comprising the polythiophene or polythiophene derivative and a polyanion, for example, obtains 3,4-ethylenedioxythiophene using an alkali metal salt of 3,4-dihydroxythiophene-2,5-dicarboxyester as a starting material. After that, potassium peroxodisulfate and iron sulfate and 3,4-ethylenedioxythiophene obtained above are introduced into polystyrenesulfonic acid aqueous solution and reacted to produce polythiophene such as poly (3,4-ethylenedioxythiophene). In addition, a composition in which a polyanion such as polystyrene sulfonic acid is complexed can be obtained.

  The coating layer in the optical polyester film of the present invention preferably contains a composition comprising the polythiophene or polythiophene derivative and polyanion and a crosslinking agent. As the crosslinking agent, for example, a melamine crosslinking agent, an epoxy crosslinking agent, an oxazoline crosslinking agent, an isocyanate crosslinking agent, an acrylamide crosslinking agent, and the like can be used. From the viewpoint of properties, it is preferable to use an epoxy-based crosslinking agent. The crosslinking agent is preferably a crosslinking agent having a molecular weight of 1000 or less, more preferably 800 or less, and still more preferably 600 or less. In particular, by using a water-soluble cross-linking agent having a molecular weight of 1000 or less, flexibility and fluidity in the stretching process are expressed, and the stretchable followability after drying of the mixture forming the coating layer is improved, and the coating film is cracked. The whitening phenomenon is suppressed and transparency is imparted. When the molecular weight becomes too large, the coating film is cracked during stretching after coating and drying, which is not preferable because transparency tends to decrease. The temperature at which the thermal loss rate of the epoxy-based crosslinking agent is 5% is preferably 230 ° C. or higher, more preferably 250 ° C. or higher, and particularly preferably 270 ° C. or higher. When the temperature at which the thermal loss rate is 5% is less than 230 ° C., the epoxy component is dispersed in the polyester film production process, particularly in the transverse stretching to heat treatment oven, which is not preferable.

  The epoxy-based cross-linking agent is preferably a water-soluble cross-linking agent since transparency and conductivity are improved. In the coating layer (B layer) of the optical polyester film of the present invention, the water-soluble crosslinking agent means a crosslinking agent having a water solubility of 80% or more, and “water solubility” means crosslinking at 23 ° C. When 10 parts of the solid content of the agent is dissolved in 90 parts of water, the ratio of the crosslinking agent is dissolved. That is, 80% water solubility means a state in which 80% by mass of 10 parts of the crosslinking agent is dissolved in 90 parts of water at 23 ° C., and the remaining 20% by mass of the crosslinking agent remains as an undissolved product. Indicates. Further, 100% water content represents a state in which 10 parts of the crosslinking agent used are all dissolved in 90 parts of water. In the coating layer (B layer) of the optical polyester film of the present invention, the epoxy crosslinking agent preferably has a water content of 90% or more, and more preferably has a water content of 100%. When the water solubility is high, not only the coating liquid itself can be made water-based but also excellent in terms of transparency and conductivity. The above-mentioned water-soluble epoxy-based crosslinking agent is preferable because it does not block and there is no contamination inside the tenter performing the heat treatment step or air pollution, compared with the addition of a high boiling point solvent such as glycerin.

  Examples of the epoxy crosslinking agent that can be used include sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, diglycerol polyglycidyl ether, and polyethylene glycol diglycidyl ether. Specifically, the epoxy compound “Denacol” manufactured by Nagase ChemteX Corporation (EX-611, EX-614, EX-614B, EX-512, EX-521, EX-421, EX-313, EX-810, EX -830, EX-850, etc.), diepoxy / polyepoxy compounds (SR-EG, SR-8EG, SR-GLG, etc.) manufactured by Sakamoto Pharmaceutical Co., Ltd., epoxy crosslinking agent “EPICLON” manufactured by Dainippon Ink Industries, Ltd. EM-85-75W, CR-5L, or the like can be suitably used, and among them, those having water solubility are preferable. The epoxy-based crosslinking agent preferably has an epoxy equivalent weight of 100 to 300 WPE in terms of reactivity. The epoxy equivalent is more preferably 110 to 200 WPE.

  In the state of the coating layer, the epoxy-based crosslinking agent may be bonded to the functional group contained in the component constituting the coating layer, may be in an unreacted state, or partially crosslinked. A structure may be formed. In the state of the coating layer, the epoxy-based crosslinking agent is preferably crosslinked in terms of the strength of the coating film, blocking resistance, stickiness, and water resistance. The crosslinking may be in a state of being bonded to a functional group contained in another component, or may be a self-crosslinking structure of the crosslinking agent itself.

  In addition, a combination of a plurality of cross-linking agents is also preferably used. For example, a combination of epoxy cross-linking agents and melamine cross-linking agents, or different types of epoxy cross-linking agents as epoxy cross-linking agents exhibits the characteristics of both. preferable. Examples of the crosslinking agent used at this time include melamine crosslinking agents, epoxy crosslinking agents, aziridine crosslinking agents, amide epoxy compounds, titanate coupling agents such as titanium chelates, oxazoline crosslinking agents, isocyanate crosslinking agents, A methylolated or alkylolated urea system, an acrylamide system, or the like can be used.

  The coated film of the optical polyester film of the present invention is a composition comprising polythiophene and / or a polythiophene derivative and a polyanion, an epoxy crosslinking agent and / or a reaction product thereof in a solid content mass ratio. The epoxy-based crosslinking agent and / or the reaction product thereof is preferably 50 to 95% by mass. For example, when the epoxy crosslinking agent and / or the reaction product thereof is less than 50% by mass, the conductivity may be difficult to be exhibited. Furthermore, when the amount of the epoxy crosslinking agent and / or its reaction product is extremely small, for example, less than 10% by mass, the insulation level is the same as that of an untreated polyester film, and the whitening of the coating film is large. The transparency is also bad. On the other hand, when the epoxy crosslinking agent and / or its reaction product exceeds 95% by mass, the transparency is improved, but the amount of the composition comprising polythiophene and / or polythiophene derivative and polyanion contributing to conductivity is small. Therefore, the conductivity becomes difficult to be expressed. Preferably, by setting the content of the epoxy crosslinking agent in the coating layer to 50 to 90% by mass, both transparency and conductivity can be achieved at a very high level.

  The optical polyester film of the present invention has a surface reflectance at a wavelength of 350 to 800 nm on the surface of the layer B side measured for a total of 25 points at intervals of 250 mm in the width direction and at intervals of 250 mm in the longitudinal direction in a section having a width of 1 m and a length of 1 m. When the wavelength at which the reflectance is minimum is λmin, and the reflectance at λmin is Rmin, the difference between the maximum value and the minimum value of λmin at the 25 measurement points is 30 nm or less, preferably 20 nm or less, more preferably 15 nm or less. In addition, the difference between the maximum value and the minimum value of Rmin is 0.5% or less, preferably 0.3% or less. When the difference between the maximum value and the minimum value of λmin is greater than 30 nm, and when the difference between the maximum value and the minimum value of Rmin is greater than 0.5%, the appearance unevenness of the optical polyester film tends to deteriorate. is there. In particular, when used as a display film for a display member or the like, uniformity in appearance is important, and even a slight unevenness is not suitable because it is defective.

  In order to reduce the reflection unevenness in the visible light region as described above, it is necessary to reduce the thickness unevenness of the coating layer (B layer). As means for reducing the thickness unevenness of the coating layer (B layer), for example, stabilizing the thickness unevenness of the coating layer by the coating device, and setting the viscosity and dynamic surface tension of the coating liquid forming the coating layer to the optimum values The method of controlling etc. is mention | raise | lifted.

  As for the viscosity of the coating liquid which forms the application layer (B layer) of the optical polyester film of this invention, 1-10 mPa * s is preferable, More preferably, it is 1-7 mPa * s. When the viscosity exceeds 10 mPa · s, the unevenness of the coating layer increases, and the appearance characteristics may deteriorate. On the other hand, when the viscosity is less than 1 mPa · s, it is necessary to lower the coating solution concentration in order to achieve the viscosity, and the antistatic property may be inferior. When a composition comprising polythiophene and / or a polythiophene derivative and a polyanion is used, the viscosity of the coating solution tends to increase, and the concentration of the coating solution is preferably 0.4 to 1.2% by mass, more preferably 0. .5 to 1.0% by mass. In addition, the coating-liquid density | concentration here represents the sum total of the mass of the composition which consists of polythiophene and / or a polythiophene derivative, a polyanion, and an epoxy type crosslinking agent as the mass of the whole coating liquid 100 mass%.

  It is also effective to control the temperature of the coating solution in order to make the viscosity within a preferable range, preferably 10 to 35 ° C, more preferably 15 to 25 ° C. When the coating liquid temperature exceeds 35 ° C., gelled products tend to be generated in the coating liquid, and when it is less than 10 ° C., the viscosity increases, which is not preferable.

  The dynamic surface tension at a frequency of 2 to 5 Hz of the coating liquid for forming the coating layer (B layer) of the optical polyester film of the present invention is preferably 30 to 60 mN / m, more preferably 30 to 50 mN / m. is there. When the dynamic surface tension is higher than 60 mN / m, the leveling property of the coating liquid is insufficient, the thickness of the coating layer becomes uneven, and the appearance may be deteriorated. Examples of the method for bringing the dynamic surface tension of the coating film forming coating solution into the above range include addition of a surfactant to the coating film forming coating solution. The surfactant added in the present invention is not particularly limited, and examples include an anionic surfactant, a nonionic surfactant, a cationic surfactant, and a zwitterionic surfactant. More specifically, examples of the anionic surfactant include sulfates of higher alcohols and salts thereof, alkylbenzene sulfonates, polyoxyethylene alkylphenyl sulfonates, polyoxyethylene alkyl diphenyl ether sulfonates, alkyls. Examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene diphenyl ether, polyoxyethylene- Po Examples thereof include oxypropylene block copolymers and acetylenic diol surfactants, and examples of cationic surfactants include alkyl (amido) betaines and alkyldimethylamine oxides. Mixtures of more than seeds can be used.

  Among these, it is preferable to use an acetylenic diol surfactant because the dynamic surface tension at a frequency of 2 to 5 Hz in the maximum bubble pressure method can be remarkably lowered and the coating property is excellent. Surfactinol 104PA, Surfinol 420, Surfinol 440, Surfinol 465, Surfinol 504, Surfinol PSA204, Surfinol PSA216, Surfinol PSA336, Dynal 604 (Air Products Japan) And Olfin EXP4051F (manufactured by Nissin Chemical Industry Co., Ltd.), and one or a mixture of two or more thereof can be used.

  The blending amount of the surfactant is preferably 0.08 to 5% by mass, assuming that the coating layer forming coating liquid having a dynamic surface tension of 30 to 60 mN / m or less at a frequency of 2 to 5 Hz is 100% by mass, Preferably it is 0.12-0.3 mass%. If it is less than 0.1% by mass, the dynamic surface tension at a frequency of 2 to 5 Hz of the coating layer forming coating liquid exceeds the above range, so that the coating thickness unevenness of the coating layer increases and the appearance becomes poor. If it exceeds 5 mass%, problems such as coating defects due to foaming of the coating liquid may occur. Further, in order to improve the leveling property, a water-soluble solvent can be used in combination, for example, alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, ethyl carbitol, ethyl cellosolve, butyl cellosolve, N- Examples include polar solvents such as methylpyrrolidone, and one or a mixture of two or more of these can be used.

  There are various methods for providing a coating layer on the base polyester film (A layer). When the optical polyester film of the present invention is produced, the coating solution is applied in the film-forming process, dried and stretched. A so-called in-line coating method in which heat treatment is performed can be suitably used. By using the in-line coating method, compared to offline processing, for example, the coating film can be made thin and uniform, the adhesion with the base polyester film is improved, and both ends in the width direction are gripped by the clip during heat treatment Therefore, there is an advantage that the film is not easily wrinkled. The method of application to the base polyester film is not particularly limited. For example, a reverse coating method, a gravure coating method, a rod coating method, a bar coating method, a metalling wire bar coating method, a die coating method, a spray coating method, or the like may be used. However, in order to reduce the appearance irregularity on the coating layer (B layer) side, a gravure coating method and a metalling wire bar coating method are preferable, and a metaling wire bar coating method is particularly preferable.

  When using the metalling wire bar coating method, it is preferable to apply the coating solution uniformly with a bar, but when a composition comprising polythiophene and / or polythiophene derivative and polyanion is used, the coating solution viscosity is high, If the liquid removal property of the coating liquid scraped off by the bar is poor, the coating appearance may be deteriorated. It is preferable to install covers as illustrated in FIGS. 1 and 2 upstream and downstream of the metering wire bar in order to smoothly remove the scraped coating liquid and prevent defects due to splashing. The gap (a) between the metalling wire bar and the upstream cover is 0.7 to 2.0 mm, and the gap (b) between the metalling wire bar and the downstream cover is narrower than (a) 0.3 to 0. It is preferable to set the thickness to 7 mm because it can ensure liquid drainage and prevent defects due to liquid splashing. If the gap (a) between the metering wire bar and the upstream cover is less than 0.7 mm, the liquid-removing property will deteriorate, so the unevenness of the reflectance may deteriorate. This is not preferable because the coating defects due to the increase. In addition, when the gap (b) between the metering wire bar and the downstream cover is less than 0.3 mm, the liquid drainage from the downstream side is deteriorated, so that the unevenness of reflectance may be deteriorated, and 0.7 mm Exceeding the thickness increases coating defects due to splashing, which is not preferable. By making the gap (a) between the metering wire bar and the upstream cover larger than the gap (b) between the metering wire bar and the downstream cover, it is possible to improve liquid drainage from the upstream side. 3 and 4, the coating liquid is directly supplied to the lower part of the metalling wire bar, the lower part of the bar is filled with the coating liquid, and the lower part of the metalling wire bar is filled with the coating liquid. In the case of using the method of applying to the film by using the rotation, it is possible to apply with a small supply amount, and the thickness unevenness of the coating layer is stabilized, which is more preferable. Further, before applying the coating liquid, the surface of the base film is subjected to a corona discharge treatment or the like, and the coating tension of the base film surface is preferably 47 mN / m or more, more preferably 50 mN / m or more. It is preferable because the adhesion and coating properties with the antistatic treatment layer can be improved. Furthermore, it is also preferable to improve the wettability and the adhesion to the substrate film by adding a slight amount of an organic solvent such as isopropyl alcohol, butyl cellosolve, N-methyl 2-pyrrolidone in the coating liquid.

The coated layer (B layer) side surface of the optical polyester film of the present invention is preferably free from scratches, more preferably the number of abrasions, in a wear test with a whiten load of 250 g / cm ² and a wear number of 100 times. There is no generation of scratches even in the wear test at 120 times. When scratches are observed when the number of wears is less than 100, there are problems such as poor scratch resistance on the surface and easy scratching when the film surface is wiped off. In order to set the scratch resistance of the surface within the above range, for example, a method of setting the thickness of the coating layer (B layer) to an appropriate range, or particles of an appropriate size are contained in the coating layer (B layer). Examples thereof include a method and a method of adding an additive that imparts slipperiness to the coating layer (B layer).

  The thickness of the coating layer (B layer) constituting the optical polyester film of the present invention is preferably 10 to 30 nm, and more preferably 12 to 20 nm. If the film thickness exceeds 30 μm, unevenness in appearance and scratch resistance tend to deteriorate, and production costs increase, which is not preferable. When the film thickness is less than 10 nm, the antistatic property may be inferior.

  It is preferable that the coating layer (B layer) which comprises the optical polyester film of this invention contains particle | grains from the point of scratch resistance and a slipperiness | lubricity. As the particles to be added, typically silica, colloidal silica, alumina, alumina sol, kaolin, talc, mica, calcium carbonate, or the like can be used. The particle | grains used should just be a thing of the range by which the effect of the optical polyester film of this invention is not impaired. The average particle diameter (d (nm)) of the particles added to the coating layer forming coating solution and the thickness (L (nm)) of the coating layer (B layer) are 0.5 ≦ d / L ≦ 3.0. It is preferable that 1.0 ≦ d / L ≦ 3.0. If d / L is less than 0.5, sufficient slipperiness cannot be imparted to the B layer side, and scratch resistance is deteriorated. On the other hand, when d / L is larger than 3.0, particles are likely to fall off from the B layer during wear, and scratches tend to occur.

  The coating layer (B layer) constituting the optical polyester film of the present invention preferably contains at least one compound selected from wax compounds, long chain alkyl acrylates, fluorine acrylates, silicone compounds, and polyolefin compounds. . The wax-based compound is not particularly limited as long as it is a composition comprising an organic substance that is solid or anti-solid at room temperature. For example, the wax-based compound is classified into natural wax, animal wax, mineral wax, or petroleum wax, and is a synthetic wax. Are classified into synthetic hydrocarbons such as polyethylene wax, modified waxes, aqueous waxes, fatty acids, acid amides, esters and ketones. The blended wax is a blend of synthetic resin with the above wax. As plant-based wax, lira wax, carnauba wax, rice wax, wood wax, jojoba oil, palm wax, etc. can be used. As animal waxes, beeswax, lanolin, whale wax, ibota wax, shellac wax and the like can be used. As the mineral wax, montan wax, ozokerite, ceresin or the like can be used. As the petroleum wax, paraffin wax, microcrystalline wax, petrolactam and the like can be used. In the present invention, any wax can be used as long as it is the above-mentioned wax, but in terms of heat resistance, synthetic waxes, mineral waxes and petroleum waxes are preferable, and synthetic waxes such as polyethylene wax are particularly preferable. The melting point of the wax compound is preferably 90 to 200 ° C, more preferably 100 to 150 ° C. In particular, when the melting point is too low, the blocking resistance tends to be poor.

  The long-chain alkyl acrylate is a copolymer acrylic resin of an acrylic monomer having an alkyl group having 12 to 25 carbon atoms in the side chain and a monomer copolymerizable with the acrylic monomer, and the copolymer acrylic resin The number of carbon atoms is such that the copolymerization ratio of an alkyl acrylate monomer having an alkyl group of 12 to 25 in the side chain is 35% by mass or more. The copolymerization amount is preferably 35 to 85% by mass, and more preferably 50 to 80% by mass in terms of blocking resistance and water resistance. Such alkyl acrylate monomer is not particularly limited as long as it satisfies the above requirements, for example, dodecyl acrylate, tridecyl acrylate, tetradecyl acrylate, pentadecyl acrylate, hexadecyl acrylate, Contains long-chain alkyl groups such as heptadecyl acrylate, octadecyl acrylate, nonadecyl acrylate, eicosyl acrylate, docosyl acrylate, tricosyl acrylate, tetracosyl acrylate, pentacosyl acrylate, dodecyl methacrylate, eicosyl methacrylate, pentacosyl methacrylate Acrylic monomers are used. The long-chain alkyl acrylate used in the present invention is preferably a water-based coating agent. For example, the following acrylic monomers can be used as other copolymerizable monomers for emulsification. As monomers, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethoxyethyl acrylate, 2-methoxyethyl acrylate, 2-butoxyethyl acrylate, methyl methacrylate, ethyl methacrylate, acrylonitrile, methacrylonitrile , Vinyl acetate, (meth) acrylic acid, styrene, itaconic acid, (meth) acrylamide, 2-hydroxyethyl (meth) acrylate, diethylene glycol mono (meth) acrylate, N-methylol (meth) acrylamide, dimethylaminoethyl (meth) ) Acrylate, diethylaminoethyl (meth) acrylate, (meth) acryloyloxyethyl phosphate ester, sodium vinyl sulfonate, sodium styrene sulfonate, maleic anhydride and the like. Long chain alkyl acrylates are most preferred because they are less likely to transfer to the back surface or process rolls as compared to wax compounds and silicone compounds.

  The coating layer (B layer) which comprises the optical polyester film of this invention may be provided on both surfaces. Also, a known functional layer for easy adhesion and the like can be provided on the opposite side of the B layer.

Further, the optical polyester film in the present invention is a group consisting of a hard coat layer, an antireflection layer, a near-infrared absorbing layer, and an electromagnetic wave absorbing layer because of its excellent antistatic performance, scratch resistance, and appearance performance with less unevenness. By providing any one or more layers (functional layers) selected from the above by a known method, an optical filter having excellent characteristics can be produced.
Further, by providing a hard coat layer on the coating layer (B layer) constituting the optical polyester film of the present invention, in addition to excellent appearance properties, the adhesion between the coating layer (B layer) and the hard coat layer. And an excellent hard coat film having antistatic properties on the surface of the hard coat layer even after the hard coat is provided on the coat layer (B layer) due to the antistatic effect of the coat layer (B layer). Can do.
The thickness of the hard coat layer in the present invention is preferably 500 to 5000 nm, and more preferably 1000 to 3000 nm. When the thickness of the hard coat layer is less than 500 nm, the surface hardness is lowered and the function as the hard coat layer may be inferior, and when it exceeds 5000 nm, the antistatic property may be inferior.
In the present invention, the material constituting the hard coat layer is not particularly limited as long as it transmits visible light, but preferably has a high light transmittance. Examples of materials used include acrylic resins, polycarbonate resins, vinyl chloride resins, polyester resins, urethane resins, and actinic radiation curable resins. In particular, acrylic resins, urethane resins, and actinic radiation curable resins can be suitably used in terms of scratch resistance, productivity, and the like.

  The actinic radiation curable resin used as a constituent component of the hard coat layer according to the present invention includes, for example, pentaerythritol tri (meth) acrylate and pentaerythritol tetra (meth) as monomer components constituting the actinic radiation curable resin. Acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, trimethylolpropane tri (meth) acrylate, bis (meth) Cloylthiophenyl) sulfide, 2,4-dibromophenyl (meth) acrylate, 2,3,5-tribromophenyl (meth) acrylate, 2,2-bis (4- (meth) acryloyloxyphenyl) Propane, 2,2-bis (4- (meth) acryloyloxyethoxyphenyl) propane, 2,2-bis (4- (meth) acryloyloxydiethoxyphenyl) propane, 2,2-bis (4- (meth) Acryloylpentaethoxyphenyl) propane, 2,2-bis (4- (meth) acryloyloxyethoxy-3,5-dibromophenyl) propane, 2,2-bis (4- (meth) acryloyloxydiethoxy-3,5 -Dibromophenyl) propane, 2,2-bis (4- (meth) acryloyloxypentaethoxy-3,5-dibromophenyl) propane, 2,2-bis (4- (meth) acryloyloxyethoxy-3,5- Dimethylphenyl) propane, 2,2-bis (4- (meth) acryloyloxyethoxy-3-phenyl) Nyl) propane, bis (4- (meth) acryloyloxyphenyl) sulfone, bis (4- (meth) acryloyloxyethoxyphenyl) sulfone, bis (4- (meth) acryloyloxypentaethoxyphenyl) sulfone, bis (4- (Meth) acryloyloxyethoxy-3-phenylphenyl) sulfone, bis (4- (meth) acryloyloxyethoxy-3,5-dimethylphenyl) sulfone, bis (4- (meth) acryloyloxyphenyl) sulfide, bis (4 -(Meth) acryloyloxyethoxyphenyl) sulfide, bis (4- (meth) acryloyloxypentaethoxyphenyl) sulfide, bis (4- (meth) acryloyloxyethoxy-3-phenylphenyl) sulfide, bis (4- (meta Acu Use of polyfunctional (meth) acrylic compounds such as loyloxyethoxy-3,5-dimethylphenyl) sulfide, di ((meth) acryloyloxyethoxy) phosphate, tri ((meth) acryloyloxyethoxy) phosphate These can be used alone or in combination of two or more.

  In addition to these polyfunctional (meth) acrylic compounds, styrene, chlorostyrene, dichlorostyrene, bromostyrene, dibromostyrene, divinylbenzene are used to control the hardness, transparency, strength, refractive index, etc. of actinic radiation curable resins. , Vinyl toluene, 1-vinyl naphthalene, 2-vinyl naphthalene, N-vinyl pyrrolidone, phenyl (meth) acrylate, benzyl (meth) acrylate, biphenyl (meth) acrylate, diallyl phthalate, dimethallyl phthalate, diallyl biphenylate, or barium A reaction product of a metal such as lead, antimony, titanium, tin, or zinc and (meth) acrylic acid can be used. These may be used alone or in combination of two or more.

  In the present invention, the description “(meth) acrylic compound” is an abbreviation of “methacrylic compound and acrylic compound”, and the same applies to other compounds.

  As a method of curing the actinic radiation curable resin in the present invention, for example, a method of irradiating with ultraviolet rays can be used. In this case, about 0.01 to 10 parts by mass of photopolymerization starts with respect to the compound. It is desirable to add an agent.

  The actinic radiation curable resin used in the present invention should not contain an antistatic agent. When an antistatic agent is included, the resin is not sufficiently cured by actinic radiation and sufficient hardness may not be obtained.

  The actinic radiation curable resin used in the present invention is not limited to isopropyl alcohol, ethyl acetate, methyl ethyl ketone, etc. within the range that does not impair the effects of the present invention for the purpose of improving workability during coating and controlling the coating film thickness. An organic solvent can be blended.

  In the present invention, active rays mean electromagnetic waves that polymerize acrylic vinyl groups such as ultraviolet rays, electron beams, and radiation (α rays, β rays, γ rays, etc.), and practically, ultraviolet rays are simple and preferable. . As the ultraviolet ray source, an ultraviolet fluorescent lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high pressure mercury lamp, a xenon lamp, a carbon arc lamp, or the like can be used. The electron beam method is advantageous in that the apparatus is expensive and requires operation under an inert gas, but it does not need to contain a photopolymerization initiator or a photosensitizer.

The hard coat layer laminated on the optical polyester film of the present invention may contain fine particles in order to impart antiglare properties. Examples of the fine particles include inorganic particles such as silicon oxide, titanium oxide, aluminum oxide, zinc oxide, tin oxide, calcium carbonate, barium sulfate, talc, kaolin, and calcium sulfate, polymethyl methacrylate, silicone, polystyrene, and polycarbonate. And organic particles made of a resin such as acrylic styrene, benzoguanamine, melamine, polyolefin, polyester, polyamide, polyimide, and polyfluorinated ethylene. These inorganic particles and organic particles may be used alone or in combination of two or more. The shape of the fine particles is not particularly limited, and may be a bead-like substantially spherical shape or a powdery indefinite shape.
The average particle size of the fine particles is preferably 30 to 75%, more preferably 30 to 50% of the thickness of the hard coat layer. When the average particle size is less than 30% of the hard coat layer thickness, it is difficult to form sufficient irregularities and the antiglare property is inferior. When it exceeds 75%, the protrusions are conspicuous and are not preferable in terms of appearance. Further, the content of the fine particles is preferably 4 to 50 parts by mass, and more preferably 15 to 40 parts by mass, when the resin component constituting the hard coat layer is 100 parts by mass.
The refractive index of the hard coat layer laminated on the optical polyester film of the present invention can be appropriately adjusted according to its function, but when a hard coat is provided on the coating layer (B layer) of the optical polyester film of the present invention. Is preferably in the range of 1.60 to 1.70, which is a relatively higher refractive index than a normal hard coat layer in order to reduce interference unevenness. In order to adjust the refractive index of the hard coat layer within the above range, it is preferable to contain metal oxide fine particles as a high refractive index component. The average primary particle diameter of the metal oxide fine particles is preferably 150 nm or less, and more preferably 100 nm or less. The lower limit of the average primary particle diameter of the metal oxide fine particles is about 3 nm. As said metal oxide fine particle, a thing with a refractive index of 1.6 or more is preferable, and a thing with a refractive index of 1.7-2.8 is used especially preferable. Examples of the metal oxide fine particles include titanium oxide, zirconium oxide, zinc oxide, tin oxide, antimony oxide, cerium oxide, iron oxide, zinc antimonate, tin oxide-doped indium oxide (ITO), and antimony-doped tin oxide (ATO). ), Aluminum-doped zinc oxide, gallium-doped zinc oxide, fluorine-doped tin oxide and the like, and these metal oxide fine particles may be used alone or in combination.

The refractive index of the high refractive index hard coat layer can be adjusted by changing the content ratio of the metal oxide fine particles. The content of the metal oxide fine particles in the high refractive index hard coat layer is preferably 30% by mass or more, more preferably 40% by mass or more, particularly 50% by mass with respect to 100% by mass of all components of the high refractive index hard coat layer. The above is preferable. Thereby, the refractive index of the high refractive index hard coat layer can be increased. The upper limit of the content of the metal oxide fine particles is preferably 90% by mass or less with respect to 100% by mass of all components of the high refractive index hard coat layer from the viewpoint of ensuring high transparency of the high refractive index hard coat layer. 80 mass% or less is more preferable.
In the present invention, it is preferable that an antireflection layer for suppressing flickering is provided on the surface of the hard coat layer having a high refractive index, or an antifouling treatment for preventing contamination is performed. The antireflection layer is not particularly limited, but is formed by stacking low-refractive-index compounds such as silica fine particles having voids inside and fluorine-containing compounds, or sputtering or vapor deposition of inorganic compounds such as magnesium fluoride and silicon oxide. can do. As for the antifouling treatment, an antifouling treatment with a silicone resin, a fluorine resin or the like can be performed. The refractive index of the low refractive index layer is preferably 1.40 or less, more preferably 1.35 to 1.37. The thickness of the low refractive index layer is suitably in the range of 50 to 150 nm, and more preferably in the range of 80 to 120 nm.

  Since the hard coat film of the present invention can prevent malfunction due to static electricity and damage of the liquid crystal cell, particularly due to its excellent antistatic properties, it can be suitably used for a polarizer protective film constituting a film for a touch panel or a polarizing plate. .

  As an example of the configuration of the touch panel film, by providing a conductive layer represented by an ITO layer on the opposite surface of the hard coat layer, a configuration combining surface protection and an upper electrode function can be obtained. Moreover, the structure of the polarizing plate generally has a structure in which both surfaces of a uniaxially stretched polyvinyl alcohol film (polarizer) containing iodine having a polarizing function are bonded with a protective film. A polarizing plate with excellent antistatic properties, surface hardness, and appearance characteristics can be obtained by laminating the opposite side of the film having a hard coat layer in this patent with a polarizer, and it is disposed on the outermost surface of the liquid crystal display, in particular. A method of use configured to be preferred.

  Next, the method for producing an optical polyester film of the present invention will be specifically described with reference to an example in which polyethylene terephthalate (hereinafter sometimes abbreviated as PET) is used as a base film, but the present invention is not limited thereto. Absent. First, commercially available PET pellets having an intrinsic viscosity of 0.5 to 0.8 dl / g are vacuum-dried and then supplied to an extruder and melted at 260 to 300 ° C. Then, after filtering with a 3-15 μm cut stainless steel fiber sintered filter (FSS), the sheet is extruded from a T-shaped die and wound around a mirror casting drum having a surface temperature of 10-60 ° C. using an electrostatic application casting method. Then, it is cooled and solidified to produce an unstretched PET film.

  This unstretched film is stretched 2.5 to 5 times in the machine direction (film traveling direction) between rolls heated to 70 to 120 ° C. At least one surface of the film is subjected to corona discharge treatment, and the surface tension is set to 47 to 58 mN / m, and then the corona-treated surface is coated with the aqueous coating liquid according to the present invention adjusted at a temperature of 25 ° C. Apply by bar method. The coated film is held by a clip and guided to a hot air zone heated to 70 to 150 ° C., dried, stretched 2.5 to 5 times in the width direction, and subsequently guided to a heat treatment zone of 160 to 250 ° C. Then, heat treatment is performed for 1 to 30 seconds to complete the crystal orientation. During this heat treatment step, a relaxation treatment of 1 to 10% may be performed in the width direction or the longitudinal direction as necessary. Biaxial stretching may be either longitudinal, transverse sequential stretching, or simultaneous biaxial stretching, and may be re-stretched in either the longitudinal or transverse direction after longitudinal and transverse stretching. The simultaneous biaxial stretching method is a method in which the machine direction and the transverse direction are simultaneously stretched, and the stretching temperature in the simultaneous biaxial method is preferably 70 to 180 ° C., and the stretching ratio is in the range of 9 to 35 times. preferable. By adding at least one substance selected from a coating layer forming composition or a reaction product of the coating layer forming composition in the base film on which the coating layer is provided, It is possible to improve the adhesiveness and to improve the slipperiness. In consideration of environmental protection and productivity, a method using recycled pellets containing the coating layer forming composition is preferred. The optical polyester film of the present invention thus obtained has a high level of conductivity, scratch resistance, and transparency regardless of changes in humidity, and further suppresses unevenness in the thickness of the coating layer. Since it is a good film, it can be suitably used as a base film for an optical filter of PDP.

Method for Measuring Characteristics and Method for Evaluating Effects The method for measuring characteristics and the method for evaluating effects in the present invention are as follows.
(1) The viscosity of the coating liquid used for the viscosity coating layer (B layer) is measured using a digital viscometer (DV-EII type, manufactured by Tokimec Co., Ltd.) under the conditions of a rotor speed of 50 rpm and a liquid temperature of 25 ° C It was.

(2) The dynamic surface tension of the coating liquid used for the dynamic surface tension coating layer (B layer) is a dynamic surface tension meter (SITA f10 manufactured by Eihiro Seiki Co., Ltd.), and the dynamic surface tension at a frequency of 2 to 5 Hz Was measured.

(3) Film thickness (L (nm)) of coating layer (B layer)
Samples of the cross-section cut into ultra thin sections, RuO ₄ staining, by OsO ₄ staining, or staining with both double staining ultramicrotomy, observed by TEM (transmission electron microscope), was photographed. The thickness of the coating layer was measured from the cross-sectional photograph. In addition, the average value of 10 places in a measurement visual field was used.
Observation method / apparatus: Transmission electron microscope (H-7100FA, manufactured by Hitachi, Ltd.)
・ Measurement conditions: Acceleration voltage 100kV
-Sample preparation: Ultra-thin section method-Observation magnification: 200,000 times.

(4) Average particle diameter (d (nm)) of particles contained in the coating layer (B layer)
The surface of the coating layer is observed with a SEM (scanning electron microscope) at a magnification of 10,000 times, and the image of the particles (light density produced by the particles) is linked to an image analyzer (for example, QTM900 manufactured by Cambridge Instrument) The data was taken in differently, and when the total number of particles became 5000 or more, the following numerical processing was performed, and the number average diameter d obtained thereby was defined as the average particle diameter (diameter).
d = Σdi / N
Here, di is the equivalent-circle diameter of the particle, and N is the number.

(5) The value of the surface specific resistance was used for the conductivity of the conductive coating layer. The surface specific resistance was measured after standing for 24 hours in a normal state (25 ° C., relative humidity 65% RH), and using the digital ultrahigh resistance / microammeter R8340A (manufactured by Advantest Corp.) under the atmosphere, applied voltage Measurement was performed after applying 100 V for 10 seconds. The unit is Ω / □. In the present invention, it was determined that those having 1 × 10 ¹⁰ Ω / □ or less have good conductivity, and those having 1 × 10 ⁸ Ω / □ or less have extremely excellent conductivity. Further, in order to measure the humidity dependency of conductivity, the same measurement as described above was performed after being left in an environment of 25 ° C. and a relative humidity of 30% RH for 1 hour. In addition, the said measurement used the average value of the measured value of 2 times, respectively.

(6) The surface of the coating layer was rubbed 120 times at a speed of 60 times / min with a load of 250 g / cm ² using a scratch-resistant whitenell (manufactured by Kowa Co., Ltd.), and the coating layer was visually observed under a 20 W fluorescent lamp. A mark indicating that the surface is not scratched and the coating layer is not peeled off is marked as particularly good, and marked as ◎, and when it is 120 times, the coating layer is peeled off but the coating layer is not scratched and the coating layer is not peeled off. Shown with a mark. In addition, evaluation was performed by indicating that the scratches and the coating layer were peeled off at 100 times, and that the scratches and the coating layer were not peeled off at 70 times, and that the scratches and peeling of the coating layer were observed at 70 times. In addition, more than (triangle | delta) was made into the acceptable range. The determination was performed by placing the sample at a position where the light source and the line of sight of the judge were perpendicular, and tilting the sample by 60 ° with respect to the perpendicular from the light source. The distance from the light source to the sample was fixed to 150 mm, and the distance from the sample to the eyes of the judge was fixed to 200 mm.

(7) In a haze normal state (23 ° C., relative humidity 65% RH), the film was allowed to stand for 2 hours, and then a fully automatic direct reading haze computer “HGM-2DP” manufactured by Suga Test Instruments Co., Ltd. was used. The average value measured three times was used as the haze value of the sample.

(8) Ultraviolet transmittance The ultraviolet transmittance of the film was measured at a wavelength of 380 nm using a spectrophotometer (U3410 manufactured by Hitachi, Ltd.).

(9) Surface reflectance of coating layer The surface reflectance on the coating layer (B layer) side is 50 mm wide black glossy tape (Yamato Co., Ltd. vinyl tape No. 200-) on the back surface of the measurement surface (B layer). 50-21: black) were bonded so that air bubbles would not bite, and then cut into approximately 4 cm square sample pieces, and a spectrophotometer (U3410, manufactured by Hitachi, Ltd.) with a φ60 integrating sphere (Hitachi, Ltd.). 130-0632) and a 10 ° inclined spacer were attached, and the surface reflectance at an incident angle of 10 ° was measured. In order to standardize the reflectance, an attached Al ₂ O ₃ plate was used as a standard reflecting plate. Measurements were taken for a total of 25 points at intervals of 250 mm in the width direction and 250 mm in the longitudinal direction in a section having a width of 1 m and a length of 1 m. And the reflectance at λmin is Rmin. The difference between the maximum and minimum values of λmin (Δλmin) is 30 nm or less and the difference between the maximum and minimum values of Rmin (ΔRmin) is 0.5% or less in the measurement of a total of 25 points. When the appearance was good, Δλmin was 15 nm or less and ΔRmin was 0.2% or less, and it was determined that the thickness unevenness of the coating layer was particularly good.
(10) Interference fringes The film thickness after curing actinic radiation curable resin (Pernox Co., Ltd. XJC-03577-1: refractive index 1.67) on a polyester film using a bar coater. It apply | coated uniformly so that it might become 300-6000 nm (C layer).

Next, with a concentrating high-pressure mercury lamp (H03-L31 manufactured by Eye Graphics Co., Ltd.) having an irradiation intensity of 120 W / cm set at a height of 9 cm from the surface of the C layer, the integrated irradiation intensity is 300 mJ / cm ² Ultraviolet rays were irradiated and cured to obtain an optical laminated film in which a hard coat layer was laminated on the laminated film. Note that an industrial UV checker (UVR-N1 manufactured by Nippon Batteries Co., Ltd.) was used for measuring the cumulative irradiation intensity of ultraviolet rays.

  The refractive index of the hard coat layer was measured at a refractive index of 633 nm with a phase difference measuring device (NPDM-1000 manufactured by Nikon Corporation) for a coating film formed on a silicon wafer by a spin coater. As a result, the refractive index of the hard coat layer was 1.67.

  Next, a sample having a size of 8 cm (laminated polyester film width direction) × 10 cm (laminated polyester film longitudinal direction) was cut out from the obtained optical laminated film, and a black glossy tape (Yamato Co., Ltd.) was formed on the opposite surface of the hard coat layer. Manufactured vinyl tape No. 200-50-21: black) was laminated so as not to bite the bubbles.

  Place this sample in a dark room 30 cm directly under a three-wavelength fluorescent lamp (3-wave daylight white (F / L 15EX-N 15W) manufactured by Matsushita Electric Industrial Co., Ltd.), and visually observe the degree of interference fringes while changing the viewing angle. Observed and evaluated as follows. Those of practical use were marked with △, and those of ◯ and above were accepted.

◎: Interference fringes are hardly visible ○: Interference fringes are slightly visible △: Weak interference fringes are visible

×: Strong interference fringes.
(11) Pencil Hardness The hardness of the hard coat film provided with the C layer was evaluated by a pencil hardness test specified by JISK5-4 (1999).

  An evaluation result of a practical level of H or higher was evaluated as Δ, a rating of 2H or higher was given as ◯, and a practical level of F or lower was lower than a practical level as x.

Next, although this invention is demonstrated based on an Example, this invention is not limited to this.

Example 1
A slurry of 45 kg of ethylene glycol per 100 kg of high-purity terephthalic acid was charged in an esterification reaction tank in which about 123 kg of bis (hydroxyethyl) terephthalate was previously charged and maintained at a temperature of 250 ° C. and a pressure of 1.2 × 10 5 Pa for 4 hours. Were sequentially supplied. After completion of the supply, an esterification reaction was further performed for 1 hour, and the esterification reaction product was transferred to a polycondensation tank. Subsequently, 0.01 parts by mass of ethyl diethylphosphonoacetate is added to the polycondensation reaction tank to which the esterification reaction product has been transferred, and 0.04 parts by mass of magnesium acetate tetrahydrate is further added as a polymerization catalyst. Antimony trioxide (manufactured by Sumitomo Metal Mining Co., Ltd.) was added to the obtained polyester so as to be 400 ppm in terms of antimony atoms. Thereafter, while stirring the low polymer at 30 rpm, the reaction system was heated from 250 ° C. to 285 ° C. over 60 minutes, and the pressure was reduced to 40 Pa. The time to reach the final pressure was 60 minutes. When the predetermined stirring torque was reached, the reaction system was purged with nitrogen, returned to normal pressure, the polycondensation reaction was stopped, discharged into cold water at 20 ° C. in a strand, and immediately cut to obtain polyethylene terephthalate (PET) pellets A1. .

This PET pellet A1 (extreme viscosity 0.63 dl / g) was sufficiently dried in vacuum, then supplied to an extruder, melted at 285 ° C., and sintered with a stainless steel fiber and compressed by a filter having an average opening of 5 μm. After filtering the stainless steel powder having a mesh size of 14 μm through a sintered filter, it was melt-extruded from a T-type die, wound around a mirror casting drum having a surface temperature of 25 ° C. using an electrostatic application casting method, and solidified by cooling. This unstretched film was heated to 90 ° C. and stretched 3.1 times in the longitudinal direction to obtain a uniaxially stretched film. This film is subjected to corona discharge treatment in air, the substrate film has a wetting tension of 55 mN / m, and the following coating layer forming coating solution is applied to the treated surface at a coating temperature of 25 ° C. It apply | coated with the wire bar. In addition, a cover as shown in FIG. 1 is installed on both the upstream and downstream sides of the metering wire bar, the gap (a) between the bar and the upstream cover is 1.0 mm, and the gap between the bar and the downstream cover ( b) was 0.5 mm. The coated uniaxially stretched film is guided to the preheating zone while being gripped with a clip, dried at 140 ° C., continuously stretched 3.5 times in the width direction in a heating zone at 120 ° C., and further heated at 225 ° C. A laminated PET film was obtained in which the base polyester film having a thickness of 100 μm having completed crystal orientation was A layer and the coating layer was B layer. Table 2 shows the characteristics of the obtained laminated film. It was excellent in antistatic properties, transparency, and scratch resistance, had little coating layer thickness unevenness, was excellent in appearance, and was suitable as an optical film. Table 2 shows the characteristics of the hard coat film provided with the C layer having a thickness of 1000 nm. A hard coat film having high antistatic properties regardless of humidity and having good interference fringes and hardness was obtained.
`` Coating layer forming coating liquid ''
-Coating liquid a1:
An aqueous coating solution of a composite composed of poly-3,4-ethylenedioxythiophene / polystyrene sulfonic acid (“Denatron F-100TP” manufactured by Nagase Chemmutex Co., Ltd.)
-Coating liquid b1:
As an epoxy crosslinking agent, an aqueous coating solution / coating in which a polyhydroxyalkane polyglycidyl ether type epoxy crosslinking agent (CR-5L (Epoxy equivalent: 180, water content: 100%) manufactured by Dainippon Ink & Chemicals, Inc.) is dissolved in water. Liquid c1:
An aqueous coating solution obtained by dissolving a long-chain alkyl group-containing acrylic resin having the following copolymer composition in water containing 5% by weight of isopropyl alcohol and 5% by weight of n-butyl cellosolve <Copolymerization component>
Lauryl methacrylate (long chain alkyl chain carbon number 18) 70% by mass
Methacrylic acid 25% by mass
2-hydroxyethyl methacrylate 5% by mass
-Coating liquid d1:
An aqueous dispersion containing 50% by mass of an acetylenic diol surfactant (“Olfin EXP4051F” manufactured by Nissin Chemical Industry Co., Ltd.)
・ Coating liquid e1:
An aqueous dispersion containing 20% by mass of colloidal silica having an average particle size of 40 nm (“Snowtex OL” manufactured by Nissan Chemical Industries, Ltd.)
A mixture of the above coating liquid a1 and coating liquid b1 in a solid content mass ratio of coating liquid a1 / coating liquid b1 = 25/75 was aged at room temperature for 5 days (abbreviated as aging coating liquid 1). . Thereafter, the aging coating liquid 1 and the coating liquids c1, d1 and e1 are in a solid mass ratio, aging coating liquid 1 / coating liquid c1 / coating liquid d1 / coating liquid e1 = 100/20/16/7, aging coating liquid What was mixed so that the solid content density | concentration of 1 might be 1.0 mass% was used as the coating layer formation coating liquid. In addition, the solid content mass ratio of each coating liquid at this time was coating liquid a1 / coating liquid b1 / coating liquid c1 / coating liquid d1 / coating liquid e1 = 25/75/20/16/7.

(Example 2)
A laminated PET film was obtained in the same manner as in Example 1 except that the following raw material A2 was used for the A layer, and the coating layer forming coating solution was changed to Table 1. The results are shown in Table 2. The resulting film is excellent in antistatic properties, transparency and scratch resistance, has little coating layer thickness unevenness, is excellent in appearance, and has excellent UV shielding properties and is suitable for optics. there were. Table 2 shows the characteristics of the hard coat film provided with the C layer having a thickness of 1000 nm. A hard coat film having high antistatic properties regardless of humidity and having good interference fringes and hardness was obtained.
・ Raw material A2
PET pellets containing no external additive particles (intrinsic viscosity 0.63 dl / g) and 2,2 '-(1,4-phenylene) bis (4H-3,1-benzoxazine-4-one) as an ultraviolet absorber Was compounded with a vented twin-screw extruder so that the ultraviolet absorber was 12% by mass to obtain a polyester containing the ultraviolet absorber. This mixture was used so that the ultraviolet absorber was 0.4% by mass with respect to the polyester film (A layer) and used as a raw material for the A layer.

(Example 3)
A laminated PET film was obtained in the same manner as in Example 1 except that the coating layer forming coating solution was changed to Table 1. The results are shown in Table 2. The antistatic property and transparency were excellent, and the coating layer thickness unevenness and scratch resistance were particularly excellent. Table 2 shows the characteristics of the hard coat film provided with the C layer having a thickness of 1000 nm. A hard coat film having high antistatic properties regardless of humidity and having good interference fringes and hardness was obtained.
-Coating liquid d2:
Acetylenediol surfactant ("Surfinol 465" manufactured by Air Products Japan Co., Ltd.)
Example 4
A laminated PET film was obtained in the same manner as in Example 1 except that the coating layer forming coating solution was changed to Table 1. The results are shown in Table 2. The antistatic property and transparency were excellent, and the coating layer thickness unevenness and scratch resistance were particularly excellent. Table 2 shows the characteristics of the hard coat film provided with the C layer having a thickness of 1000 nm. A hard coat film having high antistatic properties regardless of humidity and having good interference fringes and hardness was obtained.

(Example 5)
A laminated PET film was obtained in the same manner as in Example 1 except that the coating layer forming coating solution was changed to Table 1. The results are shown in Table 2. It was excellent in antistatic properties, transparency, and uneven coating layer thickness, and was particularly excellent in scratch resistance. Table 2 shows the characteristics of the hard coat film provided with the C layer having a thickness of 1000 nm. A hard coat film having high antistatic properties regardless of humidity and having good interference fringes and hardness was obtained.

(Example 6)
A laminated PET film was obtained in the same manner as in Example 1 except that the coating layer forming coating solution was changed to Table 1. As shown in Table 2, the results were excellent in antistatic properties and transparency. Although the coating layer thickness unevenness and scratch resistance were somewhat inferior, they were at a level usable as an optical film. Table 2 shows the characteristics of the hard coat film provided with the C layer having a thickness of 1000 nm. A hard coat film having high antistatic properties regardless of humidity and having good interference fringes and hardness was obtained.

(Example 7)
A laminated PET film was obtained in the same manner as in Example 1 except that the coating layer forming coating solution was changed to Table 1. As shown in Table 2, the results were excellent in antistatic properties, transparency, and coating thickness unevenness. Although the scratch resistance was somewhat inferior, it was a level that could be used as an optical film. Table 2 shows the characteristics of the hard coat film provided with the C layer having a thickness of 1000 nm. A hard coat film having high antistatic properties regardless of humidity and having good interference fringes and hardness was obtained.

(Example 8)
A laminated PET film was obtained in the same manner as in Example 1 except that the coating layer forming coating solution was changed to Table 1. As shown in Table 2, the results were excellent in antistatic properties and transparency, and scratch resistance and coating thickness unevenness were particularly excellent. Table 2 shows the characteristics of the hard coat film provided with the C layer having a thickness of 1000 nm. A hard coat film having high antistatic properties regardless of humidity and having less interference fringes and hardness was obtained.

Example 9
A laminated PET film was obtained in the same manner as in Example 1 except that the coating layer forming coating solution was changed to Table 1. As shown in Table 2, the results were excellent in antistatic properties, transparency, coating thickness unevenness, and scratch resistance was particularly excellent. Table 2 shows the characteristics of the hard coat film provided with the C layer having a thickness of 1000 nm. A hard coat film having high antistatic properties regardless of humidity and having good interference fringes and hardness was obtained.

(Example 10)
A laminated PET film was obtained in the same manner as in Example 1 except that the coating layer forming coating solution was changed to Table 1. As shown in Table 2, the results were excellent in antistatic properties, transparency, coating thickness unevenness, and scratch resistance. Table 2 shows the characteristics of the hard coat film provided with the C layer having a thickness of 1000 nm. A hard coat film having high antistatic properties regardless of humidity and having good interference fringes and hardness was obtained.
-Coating liquid b2:
An aqueous coating solution in which a polyhydroxyalkane polyglycidyl ether-based epoxy crosslinking agent (“Denacol” EX-512 (epoxy equivalent: 168, water content: 100%) manufactured by Nagase ChemteX Corporation)) is dissolved in water as an epoxy crosslinking agent.
-Coating liquid e2:
An aqueous dispersion containing 40% by mass of colloidal silica having an average particle diameter of 80 nm (“CATALOID SI80P” manufactured by Catalysts & Chemicals Industries, Ltd.)
(Example 11)
A laminated PET film was obtained in the same manner as in Example 1 except that the coating layer forming coating solution was changed to Table 1. As shown in Table 2, the results were particularly excellent in coating thickness unevenness and scratch resistance. Although antistatic property was somewhat inferior, it was a level which can be used as an optical film. Table 2 shows the characteristics of the hard coat film provided with the C layer having a thickness of 1000 nm. A hard coat film having high antistatic properties regardless of humidity and having good interference fringes and hardness was obtained.
-Coating liquid c2:
An aqueous coating solution obtained by dissolving a long-chain alkyl group-containing acrylic resin having the following copolymer composition in water containing 5% by mass of isopropyl alcohol and 5% by mass of n-butyl cellosolve <Copolymerization component>
Behenyl methacrylate (long chain alkyl chain carbon number 22) 70% by mass
Methacrylic acid 25% by mass
2-hydroxyethyl methacrylate 5% by mass
-Coating liquid e3:
An aqueous dispersion containing 40% by mass of colloidal silica having an average particle size of 30 nm (“Snowtex O” manufactured by Nissan Chemical Industries, Ltd.).

(Example 12)
A laminated PET film was obtained in the same manner as in Example 1 except that the coating layer forming coating solution was changed to Table 1. As shown in Table 2, the results were excellent in antistatic properties, coating thickness unevenness, and transparency. Scratch resistance was a level that could be used as an optical film, although it was slightly inferior. Table 2 shows the characteristics of the hard coat film provided with the C layer having a thickness of 1000 nm. A hard coat film having high antistatic properties regardless of humidity and having good interference fringes and hardness was obtained.

(Example 13)
A laminated PET film was obtained in the same manner as in Example 1 except that the coating layer forming coating solution was changed to Table 1. As shown in Table 2, the results were excellent in antistatic properties, coating thickness unevenness, and transparency. Scratch resistance was a level that could be used as an optical film, although it was slightly inferior. Table 2 shows the characteristics of the hard coat film provided with the C layer having a thickness of 1000 nm. A hard coat film having high antistatic properties regardless of humidity and having good interference fringes and hardness was obtained.
-Coating liquid e4:
An aqueous dispersion containing 20% by mass of colloidal silica having an average particle size of 10 nm (“Snowtex OS” manufactured by Nissan Chemical Industries, Ltd.).

(Example 14)
A laminated PET film was obtained in the same manner as in Example 1 except that the coating layer forming coating solution was changed to Table 1. As shown in Table 2, the results were excellent in antistatic properties, coating thickness unevenness, and transparency. Scratch resistance was a level that could be used as an optical film, although it was slightly inferior. Table 2 shows the characteristics of the hard coat film provided with the C layer having a thickness of 1000 nm. A hard coat film having high antistatic properties regardless of humidity and having good interference fringes and hardness was obtained.

(Example 15)
A laminated PET film was obtained in the same manner as in Example 1 except that a metal ring wire bar having a number of 4 was used. As shown in Table 2, the results were excellent in antistatic properties, coating thickness unevenness, transparency, and scratch resistance. Table 2 shows the characteristics of the hard coat film provided with the C layer having a thickness of 1000 nm. A hard coat film having high antistatic properties regardless of humidity and having good interference fringes and hardness was obtained.

(Example 16)
A laminated PET film was obtained in the same manner as in Example 1 except that the coating apparatus of FIG. 3 was used. As shown in Table 2, the results were excellent in antistatic properties, transparency, and scratch resistance, and the coating layer thickness unevenness was smaller than in Example 1, and the appearance was excellent, so that it was suitable as an optical film. Table 2 shows the characteristics of the hard coat film provided with the C layer having a thickness of 1000 nm. A hard coat film having high antistatic properties regardless of humidity and having good interference fringes and hardness was obtained.

(Example 17)
A laminated PET film was obtained in the same manner as in Example 8 except that the coating apparatus of FIG. 3 was used. As shown in Table 2, the results were excellent in antistatic properties, transparency, and scratch resistance and coating thickness unevenness were particularly excellent. Also, the characteristics of the hard coat film provided with a C layer having a thickness of 1000 nm were shown. It is shown in 2. A hard coat film having high antistatic properties regardless of humidity and having good interference fringes and hardness was obtained.
(Example 18)
A slurry of 45 kg of ethylene glycol per 100 kg of high-purity terephthalic acid was charged in an esterification reaction tank in which about 123 kg of bis (hydroxyethyl) terephthalate was previously charged and maintained at a temperature of 250 ° C. and a pressure of 1.2 × 10 5 Pa for 4 hours. Were sequentially supplied. After completion of the supply, an esterification reaction was further performed for 1 hour, and the esterification reaction product was transferred to a polycondensation tank. Subsequently, 0.01 parts by mass of ethyl diethylphosphonoacetate is added to the polycondensation reaction tank to which the esterification reaction product has been transferred, and 0.04 parts by mass of magnesium acetate tetrahydrate is further added as a polymerization catalyst. Antimony trioxide (manufactured by Sumitomo Metal Mining Co., Ltd.) was added to the obtained polyester so as to be 400 ppm in terms of antimony atoms. Further, as an additive, silica particles having an average particle diameter of 0.4 μm are added so as to be 0.015% by mass with respect to the polyester, and further, silica particles having an average particle diameter of 1.5 μm become 0.006% by mass with respect to the polyester Was added as follows. Thereafter, while stirring the low polymer at 30 rpm, the reaction system was heated from 250 ° C. to 285 ° C. over 60 minutes, and the pressure was reduced to 40 Pa. The time to reach the final pressure was 60 minutes. When the predetermined stirring torque is reached, the reaction system is purged with nitrogen, returned to normal pressure, the polycondensation reaction is stopped, discharged into cold water at 20 ° C. in a strand form, and immediately cut to obtain polyester pellets A3 containing particles. It was.
A laminated PET film was obtained in the same manner as in Example 1 except that this PET pellet A3 was used and the coating layer forming coating solution was changed to Table 1. As shown in Table 2, the results were slightly inferior in transparency and scratch resistance, but were at a level usable as an optical film. Table 2 shows the characteristics of the hard coat film provided with the C layer having a thickness of 1000 nm. A hard coat film having high antistatic properties regardless of humidity and having good interference fringes and hardness was obtained.
(Example 19)
To 100 parts by mass of 2,6-naphthalenedicarboxylic acid dimethyl ester and 60 parts by mass of ethylene glycol, 0.018 parts by mass of magnesium acetate tetrahydrate and 0.003 parts by mass of calcium acetate monohydrate as a transesterification catalyst were added. The ester exchange reaction was carried out at 170 to 240 ° C. and 0.5 kg / cm ² , and then 0.004 parts by mass of trimethyl phosphate was added to complete the ester exchange reaction. Further, 0.23 parts by mass of antimony trioxide as a polymerization catalyst was added, and a polycondensation reaction was performed under high temperature and high vacuum to obtain polyethylene naphthalate (PEN) pellets A4 having an intrinsic viscosity of 0.60 dl / g.
A laminated PEN film was obtained in the same manner as in Example 1 except that this PEN pellet A4 was used and the coating layer forming coating solution was changed to Table 1. As shown in Table 2, the results were excellent in antistatic properties, transparency and scratch resistance, had little coating layer thickness unevenness and excellent appearance, and were suitable as optical films. Table 2 shows the characteristics of the hard coat film provided with the C layer having a thickness of 1000 nm. A hard coat film having high antistatic properties regardless of humidity and having good interference fringes and hardness was obtained.
(Example 20)
A C layer having a thickness of 500 nm was provided on the laminated PET film obtained in the same manner as in Example 1 to obtain a hard coat film. The properties of the obtained hard coat film are shown in Table 2. A hard coat film having high antistatic properties regardless of humidity and having good interference fringes and hardness was obtained.
(Example 21)
The laminated PET film obtained in the same manner as in Example 1 was provided with a C layer having a thickness of 2000 nm to obtain a hard coat film. The properties of the obtained hard coat film are shown in Table 2. A hard coat film having high antistatic properties regardless of humidity and having good interference fringes and hardness was obtained.
(Example 22)
The laminated PET film obtained in the same manner as in Example 1 was provided with a C layer having a thickness of 4000 nm to obtain a hard coat film. The properties of the obtained hard coat film are shown in Table 2. A hard coat film having high antistatic properties regardless of humidity and having good interference fringes and hardness was obtained.

(Comparative Example 1)
A laminated PET film was obtained in the same manner as in Example 1 except that the coating layer forming coating solution was changed to Table 1. As shown in Table 2, the coating layer forming coating solution used had a high solid content concentration, resulting in high coating solution viscosity and poor coating thickness unevenness. Table 2 shows the characteristics of the hard coat film provided with the C layer having a thickness of 1000 nm. Although it had high antistatic properties regardless of humidity and had good hardness, the interference fringes were inferior.

(Comparative Example 2)
A laminated PET film was obtained in the same manner as in Example 1 except that the coating layer forming coating solution was changed to Table 1. As shown in Table 2, the antistatic property was inferior. Table 2 shows the characteristics of the hard coat film provided with the C layer having a thickness of 1000 nm. Although the interference fringes and hardness were good, the antistatic property was poor.

(Comparative Example 3)
A laminated PET film was obtained in the same manner as in Example 1 except that the coating layer forming coating solution was changed to Table 1. As shown in Table 2, the coating layer forming coating liquid used had a low surfactant concentration, so that the dynamic surface tension of the coating liquid was high, and the coating thickness unevenness was poor and the appearance was poor. Table 2 shows the characteristics of the hard coat film provided with the C layer having a thickness of 1000 nm. Although it had high antistatic properties regardless of humidity and had good hardness, the interference fringes were inferior.

(Comparative Example 4)
A laminated PET film was obtained in the same manner as in Example 1 except that the coating layer forming coating solution was changed to Table 1. As shown in Table 2, the coating layer forming coating solution used had a low surfactant concentration, so that the dynamic surface tension of the coating solution was high, and the coating thickness unevenness was poor and the appearance was poor. Table 2 shows the characteristics of the hard coat film provided with the C layer having a thickness of 1000 nm. Although it had high antistatic properties regardless of humidity and had good hardness, the interference fringes were inferior.

(Comparative Example 5)
A laminated PET film was obtained in the same manner as in Example 1 except that the coating layer forming coating solution was changed to Table 1. As shown in Table 2, the results were inferior in antistatic property and scratch resistance because the coating layer forming coating solution used had a low solid content and was a thin film and a high d / L. Table 2 shows the characteristics of the hard coat film provided with the C layer having a thickness of 1000 nm. Although it had high antistatic properties regardless of humidity and had good hardness, the interference fringes were inferior.

(Comparative Example 6)
A laminated PET film was obtained in the same manner as in Example 1 except that the coating layer forming coating solution was changed to Table 1. The results are shown in Table 2. As the d / L is high due to the low solid content concentration of the coating layer forming coating solution used, the scratch resistance is inferior, and the surfactant surface is low, so the dynamic surface of the coating solution Since the tension was high, the coating thickness unevenness was poor and the appearance was poor. Table 2 shows the characteristics of the hard coat film provided with the C layer having a thickness of 1000 nm. Although it had high antistatic properties regardless of humidity and had good hardness, the interference fringes were inferior.

(Comparative Example 7)
A laminated PET film was obtained in the same manner as in Example 1 except that the coating layer forming coating solution was changed to Table 1. The results are shown in Table 2. As the solid content concentration of the coating layer forming coating solution used is high, the d / L is low, so the scratch resistance is poor, and the surfactant concentration is low, so that the dynamic surface tension of the coating solution is low. Therefore, the coating thickness unevenness was poor and the appearance was poor. Table 2 shows the characteristics of the hard coat film provided with the C layer having a thickness of 1000 nm. Although it had high antistatic properties regardless of humidity and had good hardness, the interference fringes were inferior.

(Comparative Example 8)
A laminated PET film was obtained in the same manner as in Example 1 except that the coating solution for forming the coating layer was set to Table 1 and that the gap between the metalling wire bar and the cover was set to Table 1 using the coating apparatus of FIG. . As shown in Table 2, the results were poor appearance due to poor liquid drainage due to the narrow gaps (a) and (b) between the metalling wire bar and the cover, and poor coating thickness unevenness. Table 2 shows the characteristics of the hard coat film provided with the C layer having a thickness of 1000 nm. Although it had high antistatic properties regardless of humidity and had good hardness, the interference fringes were inferior.

(Comparative Example 9)
A laminated PET film was obtained in the same manner as in Example 1 except that the gap between the metalling wire bar and the cover was changed to Table 1 using the coating apparatus of FIG. As shown in Table 2, the results were poor appearance due to poor liquid drainage due to the narrow gaps (a) and (b) between the metalling wire bar and the cover, and poor coating thickness unevenness. Table 2 shows the characteristics of the hard coat film provided with the C layer having a thickness of 1000 nm. Although it had high antistatic properties regardless of humidity and had good hardness, the interference fringes were inferior.

(Comparative Example 10)
A laminated PET film was obtained in the same manner as in Example 1 except that the coating temperature of the coating layer forming coating solution was 5 ° C. As shown in Table 2, when the viscosity of the coating liquid was increased, the coating thickness unevenness was poor and the appearance was poor. Table 2 shows the characteristics of the hard coat film provided with the C layer having a thickness of 1000 nm. Although it had high antistatic properties regardless of humidity and had good hardness, the interference fringes were inferior.

(Comparative Example 11)
A laminated PET film was obtained in the same manner as in Example 1 except that the coating layer forming coating solution was changed to Table 1. As shown in Table 2, the coating layer forming coating liquid used does not contain a surfactant and particles, so that the dynamic surface tension of the coating liquid is high and the slipperiness is poor. It was inferior in thickness unevenness and scratch resistance. Table 2 shows the characteristics of the hard coat film provided with the C layer having a thickness of 1000 nm. Although it had high antistatic properties regardless of humidity and had good hardness, the interference fringes were inferior.

(Comparative Example 12)
A laminated PET film was obtained in the same manner as in Example 1 except that the coating layer forming coating solution was changed to Table 1. As shown in Table 2, the antistatic property is highly dependent on humidity, and the performance at low humidity is particularly inferior. Moreover, since the coating layer forming coating liquid used did not contain particles, the slipperiness was poor, and thus scratch resistance was poor. Table 2 shows the characteristics of the hard coat film provided with the C layer having a thickness of 1000 nm. Although the interference fringes and hardness were good, the antistatic property was poor at low humidity.
-Coating liquid f1:
An aqueous dispersion in which an acrylic resin (glass transition point 40 ° C.) having the following copolymer composition is dispersed in water in the form of particles.
(Copolymerization component)
Methyl methacrylate 65 mol%
Ethyl acrylate 35 mol%
Acrylic acid 1 mol%
N-methylolacrylamide 2 mol%
-Coating liquid g1:
Aqueous solution of polystyrene sulfonate ammonium salt (mass average molecular weight: 10,000) dissolved in water
(Comparative Example 13)
The laminated PET film obtained in the same manner as in Example 11 was provided with a C layer having a thickness of 300 nm to obtain a hard coat film. The properties of the obtained hard coat film are shown in Table 2. Although interference fringes and antistatic properties were good, the hardness was inferior.
(Comparative Example 14)
The laminated PET film obtained in the same manner as in Example 11 was provided with a C layer having a thickness of 6000 nm to obtain a hard coat film. The properties of the obtained hard coat film are shown in Table 2. Although the interference fringes and hardness were good, the antistatic property was poor.

  The optical polyester film of the present invention exhibits antistatic properties at a high level regardless of humidity change, has high transparency and scratch resistance, and further has a non-uniform thickness of the coating layer. It is useful for optical members for LCDs and PDPs, for example, because it has little unevenness in light wavelength and reflectance and is excellent in appearance. Specifically, it is suitable for an optical filter for PDP provided with one or more functional layers selected from the group consisting of a hard coat layer, an antireflection layer, a near infrared absorption layer, and an electromagnetic wave absorption layer. In addition, even when a hard coat layer is provided on the coating layer side, it exhibits antistatic properties without depending on humidity and has few interference fringes, so it is useful for polarizer protective films, surface protective films for touch panels, or electrode films for touch panels. is there.

1 Base film (A layer)
2 Advancing direction of base film 3 Metalling wire bar 4 Roll for gripping bar 5 Cover on the upstream side of the metalling wire bar 6 Cover on the downstream side of the metalling wire bar 7 Coating agent supply section 8 Liquid receiving pan 9 Coating liquid a Gap between metering wire bar and upstream cover b Gap between metalling wire bar and downstream cover 10 Hard coat layer 11 Coating layer (B layer)
12 Base film (A layer)
13 Patterned conductive layer (X electrode)
14 Patterned conductive layer (Y electrode)
15 Adhesive layer 16 Polarizer 17 Triacetylcellulose film

Claims (9)

Production of a laminated polyester film in which a coating layer (B layer) is laminated on at least one side of a base polyester film (A layer) by a metering wire bar coating method in which a cover is provided upstream and downstream of the metering wire bar. This is a method in which the gap (a) between the metalling wire bar and the upstream cover is 0.7 to 2.0 mm, and the gap (b) between the metalling wire bar and the downstream cover is narrower than that in (a). meet the following (1) to (2) which is formed by,
The coating liquid for forming the coating layer (B layer) has a viscosity of 1 to 10 mPa · s at 25 ° C. and a dynamic surface tension of 30 to 60 mN / m at a frequency of 2 to 5 Hz. A method for producing a polyester film.
(1) The specific resistance value on the surface of the B layer side at a temperature of 25 ° C. and a relative humidity of 65% RH and at a temperature of 25 ° C. and a relative humidity of 30% RH are both 10 ¹⁰ Ω / □ or less.
(2) For the surface reflectance at a wavelength of 350 to 800 nm on the surface of the layer B side measured for a total of 25 points at intervals of 250 mm in the width direction and at intervals of 250 mm in the longitudinal direction in the section of 1 m width and 1 m length, the reflectivity is minimum Where λmin is the wavelength and Rmin is the reflectance at λmin, the difference between the maximum and minimum values of λmin at the 25 measurement points is 30 nm or less, and the difference between the maximum and minimum values of Rmin is 0.5% or less. There is. The method for producing an optical polyester film according to claim 1, wherein the gap (b) is 0.3 to 0.7 mm. The method for producing an optical polyester film according to claim 1 or 2, wherein the base polyester film (A layer) contains substantially no particles and has a haze value of 1.0% or less. The method for producing an optical polyester film according to any one of claims 1 to 3, wherein the coating layer (B layer) has a thickness (L) of 10 nm to 30 nm. The coating layer (B layer) contains particles having an average particle diameter (d (nm)) and a coating layer (B layer) thickness (L (nm)) satisfying the following formula: A method for producing an optical polyester film according to claim 1.
0.5 ≦ d / L ≦ 3.0 The manufacturing method of the optical polyester film in any one of Claims 1-5 in which a coating layer (B layer) contains polythiophene. 6. The coating layer (B layer) according to any one of claims 1 to 5, comprising either a composition comprising polythiophene and a polyanion, or a composition comprising a polythiophene derivative and a polyanion, and an epoxy resin. A method for producing an optical polyester film. The method for producing an optical polyester film according to any one of claims 1 to 7, wherein the base polyester film (A layer) contains an ultraviolet absorber and has a transmittance of 5% or less at a wavelength of 380 nm. The method for producing an optical polyester film according to claim 8 , wherein the coating liquid contains a surfactant and the amount thereof is 0.08 to 5% by mass with respect to 100% by mass of the coating liquid.

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