JP4971703B2 - Polyester film for organic EL display substrate and gas barrier laminated polyester film for organic EL display substrate comprising the same - Google Patents

Description

  The present invention relates to a polyester film for gas barrier processing and a gas barrier laminated polyester film comprising the same. More specifically, the polyester film has a coating layer on at least one side of the polyester film, and is excellent in gas barrier properties by enhancing the adhesion with the base material layer, the flattening layer and the gas barrier layer, and a highly transparent polyester film for gas barrier processing, And a gas barrier laminated polyester film comprising the same, and an organic EL display substrate and an electronic paper substrate using the same.

  Polyester films, especially biaxially stretched films of polyethylene terephthalate and polyethylene naphthalate, have excellent mechanical properties, heat resistance, and chemical resistance. Therefore, magnetic tape, ferromagnetic thin film tape, photographic film, packaging film, electronic parts It is widely used as a material such as a film for electrical use, an electrical insulation film, a film for metal lamination, a film attached to the surface of a glass display, and a protective film for various members.

  Conventionally, a glass substrate has been used for an image display device represented by a liquid crystal display. In recent years, image display devices have been required to be thinner, lighter, larger in screen size, freedom of shape, curved surface display, etc., and instead of heavy and fragile glass substrates, highly transparent polymer films Substrates have been considered.

  In addition, the liquid crystal display must employ a backlight, so it is necessary to use a large number of members, while the self-luminous elements represented by organic EL can be handled with fewer members and are actively developed. Is underway. In such organic EL display applications, there is an increasing demand for improving flexibility and weight, which are one of the drawbacks of glass, and for increasing flexibility. Accordingly, various thermoplastic resins including polypropylene, polyethylene terephthalate, polyethylene-2,6-naphthalate, and polycarbonate have been studied as polymer film substrates. These polymer film substrates are generally more permeable to gas and water vapor than glass substrates. Therefore, in various image display devices including organic ELs that require high gas barrier properties, in order to apply the polymer film substrate, it is considered to stack a layer that further enhances the gas barrier property on the polymer film substrate. Specifically, various materials, film thicknesses, laminated structures, and the like have been studied.

  For example, Patent Document 1 proposes a cured polymer layer composed of a specific silicon compound and a polyvinyl alcohol polymer. For example, Patent Document 2 discloses a polyester film having a coating layer that is excellent in transparency and excellent in adhesion to a hard coat or a pressure-sensitive adhesive. And as a polymer binder constituting the coating layer, a polyester resin and a mixture of an oxazoline group and an acrylic resin having a polyalkylene oxide chain are exemplified, and mainly to improve the adhesion to the hard coat layer; It is aimed. Patent Document 3 discloses that an anchor agent layer provided between a base film made of a thermoplastic resin film and a gas barrier layer includes an anchor agent and a silane coupling agent. It has been proposed to improve the gas barrier property by increasing the adhesion between the gas barrier layer and the gas barrier layer.

  However, when used in an image display device such as an organic EL display or electronic paper, where the element is likely to be deteriorated by moisture or oxygen, the adhesion between the polyester base film and the gas barrier layer is still insufficient with these coating layers. The present situation is that high gas barrier properties required for organic EL displays and electronic paper are not obtained.

JP-A-10-111500 JP 2004-9362 A JP-A-2005-1242

  An object of the present invention is to provide a polyester film for gas barrier processing which has a high gas barrier property when the gas barrier layer is laminated, and has high transparency and easy processability, by solving the problems of the prior art. is there. Another object of the present invention is to provide a polyester film for gas barrier processing that has gas barrier properties, high transparency, and easy processability, and that maintains the gas barrier properties even after high-temperature heat treatment.

  Another object of the present invention is to provide a gas barrier laminated polyester film having high transparency and easy processability and high dimensional stability against changes in humidity, and thus has high gas barrier properties.

  As a result of intensive studies to solve the above problems, the present inventors provide a coating layer containing a copolyester resin, polyvinyl alcohol and fine particles in a specific ratio on at least one side of a base film made of polyester. As a result, the adhesion between the base film made of polyester and the flattening layer or the gas barrier layer is increased through the coating layer, so that defects such as water vapor and oxygen permeation paths are reduced, and some stress is applied. It has been found that a polyester film having high gas barrier properties and excellent transparency can be obtained because it becomes difficult for defects to be generated at each interface separation or cracks to occur in the gas barrier layer. The invention has been completed.

That is, according to the present invention, an object of the present invention, there is provided a port Li ester film coating layer is provided on at least one surface of a substrate film made of polyester, polyester constituting the substrate film be polyethylene naphthalate The coating layer is based on the weight of the coating layer (A) 50 to 80% by weight of a copolyester resin having a glass transition point of 20 to 90 ° C., and (B) the degree of saponification is 74 to 90 mol%. polyvinyl alcohol 10 to 30 wt%, (C) fine particles 3 to 25% by weight, and (D) a crosslinking agent containing from 1 to 20 wt%, total light transmittance of the polyester film 85% or more, haze There is 1.5% or less, and 200 ° C. × thermal shrinkage MD direction at 10 minutes, TD directions Ru der 0.2% or less organic EL display substrate Po Riesute This is achieved by a film (item 1).

The organic EL Po Li ester film for display substrate of the present invention includes, as a preferred embodiment, the heat shrinkage MD direction at 0.99 ° C. × 30 minutes, and TD directions than 0.1% der Ru state like.

The present invention is laminated stacked construction gas barrier layer is laminated on at least one coating layer of Po Li ester film for an organic EL display substrate, or the planarizing layer coating film layer, the gas barrier layer are sequentially stacked configuration, one of the MD direction and the TD direction of the humidity expansion coefficient αh organic EL display substrate for the gas barrier laminated polyester respectively 1-10 ppm /% RH in the gas barrier laminated polyester film for an organic EL display substrate having a laminated structure of Includes film.
Further, the present invention also encompasses an organic EL display substrate comprising such an organic EL display gas barrier laminate polyester film for the substrate.

  According to the present invention, the polyester film for gas barrier processing according to the present invention has a high gas barrier property when a gas barrier layer is further provided, and also has high transparency and slipperiness. It can be suitably used as a substrate film such as an organic EL display and electronic paper. Moreover, since the gas barrier laminated polyester film of the present invention has high gas barrier properties and also has high transparency and slipperiness, it is suitably used as an organic EL display substrate and electronic paper substrate that require these characteristics. be able to.

The present invention will be described in detail below.
<Base film>
The base film of the present invention is made of polyester. As the polyester of the present invention, an aromatic polyester synthesized from an aromatic dicarboxylic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof can be used. Examples of the aromatic dicarboxylic acid component include terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, and 4,4′-diphenyldicarboxylic acid. Examples of the diol component include ethylene glycol, 1,3-propanediol, and 1,4- Examples include butanediol, 1,4-cyclohexanedimethanol, and 1,6-hexanediol. Specific examples of the polyester of the present invention include polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, poly (1,4-cyclohexylenedimethylene terephthalate), polyethylene naphthalate, and polytrimethylene naphthalate. In particular, polyethylene terephthalate and polyethylene naphthalate are preferable from the viewpoint of balance between mechanical properties and optical properties, and polyethylene naphthalate is most preferable from the viewpoint of gas barrier properties and heat resistance expressed by heat shrinkage. The polyester may be a homopolymer, a copolymer copolymerized with a third component, or a polymer blend.

  When the polyester is polyethylene naphthalate, naphthalenedicarboxylic acid is used as the main dicarboxylic acid component, and ethylene glycol is used as the main diol component. Examples of the naphthalenedicarboxylic acid include 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, and 1,5-naphthalenedicarboxylic acid. Among these, 2,6-naphthalenedicarboxylic acid is preferable. Here, “main” means at least 90 mol%, preferably at least 95 mol% of all repeating units constituting the polyester.

  When polyethylene naphthalate is a copolymer, examples of copolymer components constituting the copolymer include oxalic acid, adipic acid, phthalic acid, sebacic acid, dodecanedicarboxylic acid, isophthalic acid, terephthalic acid, 1,4-cyclohexanedicarboxylic acid, 4 , 4′-diphenyldicarboxylic acid, phenylindanedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, tetralindicarboxylic acid, decalindicarboxylic acid, diphenyletherdicarboxylic acid and the like; p-oxybenzoic acid, p-oxyethoxybenzoic acid Or trimethylene glycol, tetramethylene glycol, hexamethylene glycol, cyclohexane methylene glycol, neopentyl glycol, ethylene oxide of bisphenol sulfone Addendum, ethylene oxide adduct of bisphenol A, diethylene glycol, can be preferably used such diol polyethylene oxide glycol. These copolymer components may be used alone or in combination of two or more. Among these copolymer components, preferred acid components are isophthalic acid, terephthalic acid, 4,4′-diphenyldicarboxylic acid, 2,7-naphthalenedicarboxylic acid, p-oxybenzoic acid, and preferred diol components. Is an ethylene oxide adduct of trimethylene glycol, hexamethylene glycol, neopentyl glycol, bisphenol sulfone.

  When polyethylene naphthalate is a polymer blend, the blend components include polyethylene terephthalate, polyethylene isophthalate, polytrimethylene terephthalate, polyethylene-4,4′-tetramethylene diphenyldicarboxylate, polyethylene-2,7-naphthalene dicarboxylate. , Polytrimethylene-2,6-naphthalene dicarboxylate, polyneopentylene-2,6-naphthalene dicarboxylate, poly (bis (4-ethyleneoxyphenyl) sulfone) -2,6-naphthalene dicarboxylate And the like. These blend components may be used alone or in combination of two or more.

  The polyester of the present invention may be one in which a terminal hydroxyl group and / or carboxyl group is partially or entirely blocked with a monofunctional compound such as benzoic acid or methoxypolyalkylene glycol. Further, it may be copolymerized with a very small amount of trifunctional or higher functional ester-forming compound such as glycerin and pentaerythritol within a range where a substantially linear polymer is obtained.

The polyester of the present invention is a conventionally known method, for example, a method of directly obtaining a low-polymerization degree polyester by reaction of a dicarboxylic acid and a diol, or a lower alkyl ester of a dicarboxylic acid and a diol are converted to a conventionally known transesterification catalyst such as sodium, potassium, It can be obtained by a method in which a reaction is carried out using one or more of compounds containing magnesium, calcium, zinc, strontium, titanium, zirconium, manganese, and cobalt, followed by a polymerization reaction in the presence of a polymerization catalyst. Polymerization catalysts include antimony compounds such as antimony trioxide and antimony pentoxide, germanium compounds represented by germanium dioxide, tetraethyl titanate, tetrapropyl titanate, tetraphenyl titanate or partial hydrolysates thereof, and titanyl ammonium oxalate. , Titanium compounds such as potassium titanyl oxalate and titanium trisacetylacetonate can be used.
When polymerization is performed via a transesterification reaction, a phosphorus compound such as trimethyl phosphate, triethyl phosphate, tri-n-butyl phosphate, or normal phosphoric acid is usually added for the purpose of deactivating the transesterification catalyst before the polymerization reaction. Is done. The phosphorus compound preferably has a polyester content of 20 to 100 ppm as a phosphorus element from the viewpoint of thermal stability of the polyester.
The polyester may be converted into chips after melt polymerization, and further subjected to solid phase polymerization under heating under reduced pressure or in an inert gas stream such as nitrogen.

  The intrinsic viscosity of the polyester is preferably 0.40 dl / g or more, and more preferably 0.40 to 0.90 dl / g. If the intrinsic viscosity is less than 0.40 dl / g, cutting may occur frequently in the film forming process. If the intrinsic viscosity is higher than 0.90 dl / g, melt extrusion is difficult because of high melt viscosity, and the polymerization time is long and uneconomical. Further, the intrinsic viscosity of the polyester after being formed on the biaxially oriented film is preferably 0.38 to 0.85 dl / g, and more preferably 0.40 to 0.80 g / dl. The intrinsic viscosity is a value measured at 35 ° C. using o-chlorophenol as a solvent.

The base film of the present invention preferably does not contain fine particles used as a lubricant.
The base film of the present invention has a Young's modulus in both the MD direction (hereinafter sometimes referred to as a continuous film-forming direction, the longitudinal direction, and the longitudinal direction) and the TD direction (hereinafter sometimes referred to as a width direction and a lateral direction). It is preferable that it is 4.5 GPa or more. When the Young's modulus of the substrate film is less than the lower limit, the humidity expansion coefficient αh as a laminated film is 10 ppm /% RH or less even if the coating layer and the gas barrier layer are appropriate for the later-described humidity expansion coefficient. May not be in range. As a specific means for setting the Young's modulus of the base film to 4.5 GPa or more in both the MD direction and the TD direction, the base film is stretched in the MD direction and the TD direction at a magnification of 2.9 times or more. It is done. On the other hand, the upper limit of the Young's modulus of the base film is the MD direction and TD in the case of increasing the dimensional stability at a temperature change, particularly at a high temperature range of 200 ° C., and maintaining a high gas barrier property even after receiving such a thermal history. The direction is preferably 7.0 GPa or less. When the Young's modulus of the base film exceeds the upper limit, the heat-resistant dimensional stability at 200 ° C. is poor, and the gas barrier layer deteriorates as a result of being broken due to cracks in the gas barrier layer. There is. As a specific means for setting the Young's modulus of the base film to 7.0 GPa or less in both the MD direction and the TD direction, the base film is stretched in the MD direction and the TD direction at a magnification of 3.9 times or less. It is done.

  The thickness of the base film is preferably 12 to 500 μm in order to obtain strength and flexibility required for use as a support for organic EL displays, electronic paper, liquid crystal displays, solar cells, organic TFTs, and the like. . When used as a support for electronic paper, the thickness of the substrate film is more preferably 12 to 50 μm, particularly preferably 12 to 25 μm. Moreover, the thickness of the base film when used as a support for an organic EL display, a liquid crystal display, a solar cell, an organic TFT or the like is more preferably 25 to 350 μm, and particularly preferably 50 to 250 μm. When the thickness of the base film is less than the lower limit, in the layer configuration including the coating film layer and the gas barrier layer on one side of the base film, the moisture expansion due to the insufficient effect of reducing the water vapor diffusion rate by the layer configuration is exhibited. The coefficient αh may exceed the upper limit, and the gas barrier property may decrease.

  The thicker the base film, the more easily the effect of reducing the diffusion rate of water vapor due to the layer structure. However, since the base film is required to be thin within a range satisfying flexibility and characteristics, the upper limit of the thickness of the base film is preferably in the above-described range.

<Coating layer>
The base film made of the polyester of the present invention has a coating layer containing the following (A) to (C) on at least one surface. A coating-film layer is obtained by drying, after apply | coating the coating liquid containing (A)-(C) on a base film.
(A) Copolyester resin 50-80% by weight
(B) 10-30% by weight of polyvinyl alcohol
(C) 3-25% by weight of fine particles
Here, the weight of the coating layer is the same as the solid content contained in the coating solution. (A)-(C) Content of each component is content which made the weight of the coating-film layer 100 weight%.

  The coating film layer of the present invention is composed of the above components, so that the base film made of polyester and the planarization layer (when the planarization layer is laminated on the coating film layer) via the coating film layer Or adhesiveness with a gas barrier layer (when a gas barrier layer is laminated | stacked on a coating-film layer) increases. As a result, excellent gas barrier properties are exhibited when the gas barrier layer is further laminated with excellent transparency and film processability.

  In particular, as a remarkable effect of each component focusing on the gas barrier property, (A) the copolyester component has an effect of enhancing the adhesiveness with the polyester base layer, and (B) the polyvinyl alcohol component is a flattening layer or a gas barrier layer. It has the effect of improving the adhesiveness. Further, as described in detail below, the content of each component also contributes to gas barrier performance.

<Copolyester resin>
The copolyester resin (A) that forms the coating layer is a copolyester composed of a polybasic acid or an ester-forming derivative thereof and a polyol or an ester-forming derivative thereof, and synthesized using at least two acid components. When a copolyester resin is used, the glass transition point and the crystallization temperature can be easily adjusted.

  The copolyester resin (A) is preferably a copolyester resin having a glass transition point in the range of 20 to 90 ° C. When the glass transition point is less than 20 ° C., the films are likely to block each other. On the other hand, when the glass transition point exceeds 90 ° C., the scraping property of the film may be lowered, or the coating layer may become brittle and the adhesion may not be maintained.

  The following can be used as a structural component of the polyester resin having such a glass transition point. That is, terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, phthalic acid, phthalic anhydride, 1,4-cyclohexanedicarboxylic acid, adipic acid, sebacic acid, trimellitic acid, pyromellitic acid as main polybasic acid components And dimer acid. Further, an extremely small amount of unsaturated polybasic acid components such as maleic acid, itaconic acid and the like and p-hydroxybenzoic acid and the like can be used. In addition, as a polyol component, ethylene glycol, diethylene glycol, dipropylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, xylene glycol, dimethylolpropane, trimethylolpropane, glycerin, Examples include poly (ethylene oxide) glycol, poly (tetramethylene oxide) glycol, and bisphenol-A alkylene oxide adducts.

  The copolyester resin (A) may use a dicarboxylic acid component having a sulfonate group in order to impart hydrophilicity. Examples of the dicarboxylic acid component having a sulfonate group include 5-sodium sulfoisophthalic acid, 5-potassium sulfoisophthalic acid, and 5-potassium sulfoterephthalic acid. The dicarboxylic acid component having a sulfonate group is preferably copolymerized in an amount of 1 to 16 mol%, more preferably 1.5 to 14 mol%, based on the total acid components in the molecule. When the dicarboxylic acid component having a sulfonate group is less than the lower limit, the hydrophilicity of the copolyester resin may be insufficient. On the other hand, when the upper limit is exceeded, the moisture resistance of the coating layer may be reduced and the gas barrier property may be poor. is there.

  Content of a copolyester resin (A) is 50 to 80 weight% on the basis of the weight of a coating-film layer. When the content of the copolyester resin is less than 50% by weight, the adhesion with the polyester film is insufficient. On the other hand, when the content exceeds 80% by weight, the adhesion with the planarizing layer or the gas barrier layer is lowered. Therefore, when the content of the copolyester resin (A) exceeds this range, the humidity expansion coefficient αh of the laminated film exceeds the upper limit, and sufficient gas barrier performance cannot be obtained.

<Polyvinyl alcohol>
Polyvinyl alcohol or a copolymer thereof is used as the polyvinyl alcohol (B) that forms the coating layer. Examples of the polyvinyl alcohol copolymer include a vinyl alcohol-vinyl acetate copolymer, a vinyl alcohol-vinyl butyral copolymer, an ethylene-vinyl alcohol copolymer, and a polyvinyl alcohol polymer having a silyl group in the molecule. Of these, vinyl alcohol-vinyl acetate copolymer and ethylene-vinyl alcohol copolymer are preferable. Usually, the copolymerization ratio of vinyl alcohol is represented by the degree of saponification. The polyvinyl alcohol (B) of the present invention preferably has a saponification degree of 74 to 90 mol%. If the degree of saponification is less than 74 mol%, the moisture resistance of the coating layer may be lowered and the gas barrier property may be poor. On the other hand, when the degree of saponification exceeds 90 mol%, the adhesion to the planarizing layer or the gas barrier layer and the blocking resistance may be lowered.

  The content of polyvinyl alcohol (B) is 10 to 30% by weight based on the weight of the coating layer. If the content of polyvinyl alcohol is less than 10% by weight, sufficient adhesion to the planarizing layer or gas barrier layer cannot be obtained. On the other hand, when the content of the polyvinyl alcohol exceeds 30% by weight, the blocking resistance is lowered or the moisture resistance is lowered, resulting in poor gas barrier properties.

<Fine particles>
The fine particles (C) forming the coating layer may be either organic or inorganic, and include calcium carbonate, calcium oxide, aluminum oxide, kaolin, silicon oxide, zinc oxide, crosslinked acrylic resin particles, crosslinked polystyrene resin particles, melamine resin particles, Crosslinked silicone resin particles are exemplified. The fine particles (C) of the present invention preferably have an average particle size of 20 to 100 nm. When the average particle size of the fine particles is less than 20 nm, the films are likely to block each other. On the other hand, when the average particle size exceeds 100 nm, the shaving property may be deteriorated or the adhesion with the planarizing layer or the gas barrier layer may be deteriorated.

  Content of microparticles | fine-particles (C) is 3-25 weight% on the basis of the weight of a coating-film layer. If the content of the fine particles is less than 3% by weight, the slipperiness (conveyability) of the film is insufficient. Decreases and the gas barrier property becomes poor.

<Crosslinking agent>
The coating layer of the present invention may further contain (D) 1 to 20% by weight of a crosslinking agent. By containing a crosslinking agent, the gas barrier property can be further improved. As the crosslinking agent (D) for forming the coating layer, it is preferable to use at least one selected from the group consisting of an oxazoline group-containing polymer, a urea resin, a melamine resin, and an epoxy resin. When the content of the crosslinking agent is less than 1% by weight, the blocking property of the coating layer may be insufficient and the gas barrier property may be insufficiently improved. On the other hand, when the content exceeds 20% by weight, it is difficult to form a coating film. Thus, sufficient adhesion with the planarization layer or the gas barrier layer may not be obtained, and the improvement of the gas barrier property may be insufficient.

（式中、Ｒ¹、Ｒ²、Ｒ³およびＲ⁴は、それぞれ、水素、ハロゲン、アルキル基、アラルキル基、フェニル基および置換フェニル基からなる群から選ばれる置換基を示し、Ｒ⁵は付加重合性不飽和結合基を有する非環状有機基を示す。） Specific examples of the oxazoline group-containing polymer include a polymer obtained by polymerizing an addition-polymerizable oxazoline (a) represented by the following formula (I) and, if necessary, another monomer (b).

^{(Wherein, R 1, R 2, R} 3 and R ⁴ each represents hydrogen, a halogen, an alkyl group, an aralkyl group, a substituent selected from the group consisting of a phenyl group and a substituted phenyl group, R ⁵ is added An acyclic organic group having a polymerizable unsaturated bond group is shown.)

  Specific examples of the addition-polymerizable oxazoline (a) represented by the formula (I) include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2. -Oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-methyl-2-oxazoline, etc. It can be used as a mixture of seeds or more. Of these, 2-isopropenyl-2-oxazoline is preferred because it is easily available industrially.

  The monomer (b) other than the addition polymerizable oxazoline is not particularly limited as long as it is a monomer copolymerizable with the addition polymerizable oxazoline (a), and examples thereof include methyl (meth) acrylate and butyl (meth) acrylate. Acrylic esters, unsaturated carboxylic acids such as acrylic acid, methacrylic acid and itaconic acid, unsaturated nitriles such as acrylonitrile and methacrylonitrile, and unsaturated amides such as (meth) acrylamide and N-methylol (meth) acrylamide , Vinyl esters such as vinyl acetate and vinyl propionate, vinyl ethers such as methyl vinyl ether and ethyl vinyl ether, α-olefins such as ethylene and propylene, halogen-containing α, β-unsaturated monomers such as vinyl chloride, styrene Α, β-unsaturated aromatic mono And the like. These can be used as one kind or a mixture of two or more kinds.

  When the addition-polymerizable oxazoline (a) and at least one other monomer (b) are used to obtain a polymer, the amount of addition-polymerizable oxazoline (a) is 0.5% by weight based on the total monomers. It is preferable to determine appropriately within the above range. When the addition amount of the addition polymerizable oxazoline (a) is less than 0.5% by weight, it may be difficult to achieve the object of the present invention.

  Specific examples of the epoxy resin include polyepoxy compounds, diepoxy compounds, and monoepoxy compounds. Examples of the polyepoxy compound include sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, triglycidyl tris (2-hydroxyethyl) isocyanate, glycerol polyglycidyl ether, trimethylolpropane poly Glycidyl ether, N, N, N ′, N′-tetraglycidylmetaxylylenediamine, N, N, N ′, N′-tetraglycidyl-4,4′-diaminodiphenylmethane, N, N, N ′, N ′ -Tetraglycidyl-1,3-bisaminomethylcyclohexane etc. can be mentioned.

  Examples of the diepoxy compound include neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, resorcin diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, and polypropylene glycol diglycidyl. Examples include ether and polytetramethylene glycol diglycidyl ether.

Examples of the monoepoxy compound include allyl glycidyl ether, 2-ethylhexyl glycidyl ether, and phenyl glycidyl ether.
Among these, N, N, N ′, N′-tetraglycidylmetaxylylenediamine, N, N, N ′, N′-tetraglycidyl-4,4′-diaminodiphenylmethane, N, N, N ′, N ′ -Tetraglycidyl-1,3-bisaminomethylcyclohexane is preferably exemplified.

  Preferred examples of the urea resin include dimethylol urea, dimethylol ethylene urea, dimethylol propylene urea, tetramethylol acetylene urea, 4-methoxy 5-dimethylpropylene urea dimethylol and the like.

  Preferred examples of the melamine-based resin include compounds obtained by reacting methylol melamine derivatives obtained by condensing melamine and formaldehyde with methyl alcohol, ethyl alcohol, isopropyl alcohol, or the like as a lower alcohol, and mixtures thereof. Examples of the methylol melamine derivative include monomethylol melamine, dimethylol melamine, trimethylol melamine, tetramethylol melamine, pentamethylol melamine, hexamethylol melamine and the like.

Of these crosslinking agents (D), epoxy resins, particularly polyepoxy compounds are preferred. These crosslinking agents may be used alone or in combination of two or more in some cases.
Moreover, it is preferable that the surface energy of the coating film layer of this invention is 50-65 dyne / cm, and it is especially preferable that it is 55-62 yne / cm. If this surface energy is less than the lower limit, the coatability and adhesiveness of the planarizing layer may be poor. On the other hand, when the surface energy of the coating layer exceeds the upper limit, the adhesion with the base film made of polyester may be insufficient, or the moisture resistance of the coating layer may be insufficient. In order to obtain a coating layer having such surface energy, (A) a copolyester resin, (B) polyvinyl alcohol, (C) fine particles, and (D) a crosslinking agent are blended in the above ranges, respectively (A ) To (D), for example, by coating with a thickness of 0.02 to 1 μm using a coating solution containing the component. The method of coating may be either a method of coating in the stretching step during film formation, or a method of coating after film stretching, but in terms of adhesion of the coating film to the polyester film, A method of coating in the film forming step is preferred.
In addition to the above components, an antistatic agent, a colorant, a surfactant (wetting agent), an ultraviolet absorber and the like are used as components for forming the coating layer within a range not impairing the problems of the present invention. May be.

<Total light transmittance>
The gas barrier processing polyester film of the present invention needs to have a total light transmittance of 85% or more measured in accordance with JIS standard K7105. When the total light transmittance is less than 85%, the transparency is deteriorated. Therefore, when used for a display, the luminance is lowered. The total light transmittance is more preferably 87% or more, and particularly preferably 90% or more. In order to make the total light transmittance within the above-mentioned range, it is necessary not to contain a filler in the substrate film, and the coating layer containing the components (A) to (C) is at least on one side, preferably on both sides. By providing, the total light transmittance is further improved.

<Haze>
The polyester film for gas barrier processing of the present invention is required to have a haze of 1.5% or less measured according to JIS standard K7105. When the haze exceeds 1.5%, the transparency is deteriorated. Therefore, when used for a display, the display screen looks white and the contrast is lowered. The haze is more preferably 1.0% or less, and particularly preferably 0.5% or less. In order to make haze into the above-mentioned range, it is necessary not to contain a filler in a board | substrate film, and it is achieved by a coating-film layer containing (A)-(C) component.

<Heat shrinkage>
The polyester film for gas barrier processing of the present invention preferably has a thermal shrinkage rate at 150 ° C. for 30 minutes of 0.1% or less in each of the MD direction and the TD direction. When the thermal shrinkage rate exceeds the upper limit, the functional layer is cracked or wrinkled in a high temperature atmosphere around 150 ° C. when or after laminating various functional layers including a gas barrier layer on the polyester base film. As a result, the functional layer may be destroyed and functions including gas barrier properties may not be sufficiently exhibited. The thermal shrinkage rate at 150 ° C. for 30 minutes is more preferably 0.05% or less, and particularly preferably 0.03% or less.
In order to make the heat shrinkage rate at 150 ° C. within the above-mentioned range, in the film forming process of the polyester film, the film is stretched in the vertical and horizontal directions and then at a temperature of (Tm-100) to (Tm-5) ° C. This is achieved by performing heat setting for 100 seconds and then performing relaxation treatment at a temperature of (X-80) to X ° C. Here, Tm represents a melting point, and X represents a heat setting temperature.

The polyester film for gas barrier processing of the present invention preferably has a thermal shrinkage rate at 200 ° C. for 10 minutes of 0.2% or less in each of the MD direction and the TD direction. A high gas barrier property is maintained even after receiving a heat history in the vicinity of 200 ° C. because the thermal contraction rate at 200 ° C. for 10 minutes of the polyester base film is within this range. When the thermal shrinkage rate exceeds the upper limit, the functional layer is cracked when various functional layers including a gas barrier layer are laminated on the polyester film or when there is a work process in a high-temperature atmosphere around 200 ° C. after the lamination. As a result of entering or wrinkling, the functional layer may be destroyed and functions including gas barrier properties may not be sufficiently exhibited. The thermal shrinkage rate at 200 ° C. for 10 minutes is more preferably 0.1% or less, particularly preferably 0.05% or less.
In order to make the heat shrinkage rate at 200 ° C. within the above range, in the film forming process of the polyester film, the film is stretched by 3.9 times or less in the vertical and horizontal directions, and (Tm-100) to (Tm-5) ° C. This is achieved by performing heat setting at a temperature of 1 to 100 seconds and then performing a relaxation treatment at a temperature of (X-80) to X ° C. The base film having a thermal shrinkage at 200 ° C. is also provided with a Young's modulus of 7.0 GPa or less at the same time.

<Planarization layer>
According to the present invention, there is provided a laminated polyester film for gas barrier processing in which a flattening layer is further laminated on at least one coating layer of the polyester film for gas barrier processing for the purpose of enhancing gas barrier properties. There are no particular limitations on the type of the planarizing layer in the present invention and the method of forming the layer as long as it has a function of planarizing the surface and adhering the layers. By laminating the gas barrier layer on the base film through the coating layer and the flattening layer, it is possible to reduce defects that cause gas permeation. The effects of the planarization layer that focuses on gas barrier properties are that the surface of the gas barrier layer is less susceptible to defects such as pinholes and cracks, and the adhesion between the coating layer and the planarization layer is high. In addition, it is possible to reduce defects that become gas permeation paths. As a result, when the planarization layer is included, the humidity expansion coefficient αh is excellent, and the gas barrier property is improved.

  The planarizing layer is preferably formed by coating, and may be referred to as a primer layer or an anchor layer. As a planarizing layer, for example, a thermosetting resin such as a silicon-containing resin or an epoxy resin, a radiation curable resin such as an ultraviolet curable acrylic resin, a melamine resin, a urethane resin, an alkyd resin, polyacrylonitrile, acrylonitrile-methyl acrylate Examples thereof include acrylonitrile copolymers such as polymers and acrylonitrile-styrene copolymers, polyvinylidene chloride, vinyl alcohol and copolymers thereof, and it is preferable to use a coating composition containing at least one of these.

  Among these, a planarization layer containing a silicon-containing resin, polyvinyl alcohol, and a copolymer thereof is preferable because adhesion to the coating layer is further increased. As a more preferred planarizing layer, an epoxy silicon compound selected from the group consisting of (a) a silicon compound having an epoxy group and an alkoxysilyl group, a (partial) hydrolyzate thereof, a (partial) condensate thereof, and a mixture thereof. (B) A silicon compound having an amino group and an alkoxysilyl group, a (partial) hydrolyzate thereof, a (partial) condensate thereof, and a mixture thereof, and (c) polyvinyl Examples thereof include a cured polymer layer obtained by cross-linking alcohol or a polyvinyl alcohol copolymer. When a cured polymer obtained by crosslinking the components (a) to (c) is used as the planarizing layer, it has excellent surface smoothness, adhesion to the coating layer and gas barrier layer, durability, and flexibility. Further, the gas barrier property is further improved.

(A) The silicon compound having an epoxy group and an alkoxysilyl group is, for example, the following general formula (II)
R ⁷ _n
｜
X-R ⁶ -Si (OR ⁸ ) _3-n (II)
(In the above formula, R ⁶ is an alkylene group having 1 to 4 carbon atoms, R ⁷ and R ⁸ are alkyl groups having 1 to 4 carbon atoms, X is a glycidoxy group or an epoxycyclohexyl group, and n is 1 or 0. )
The compound represented by these is mentioned.

Among the silicon compounds having an epoxy group and an alkoxysilyl group represented by the general formula (II), 3-glycidoxypropyltrimethoxysilane and (3,4-epoxycyclohexyl) ethyltrimethoxysilane are particularly preferable. These compounds can be used alone or in combination of two or more.
The (partial) hydrolyzate of a silicon compound having an epoxy group and an alkoxysilyl group is a product obtained by hydrolyzing a part or all of the silicon compound. The (partial) condensate is a condensate obtained by condensation reaction of a part or all of the hydrolyzate of the silicon compound, and a condensate of the condensate and a raw silicon compound that is not hydrolyzed. They are obtained by a so-called sol-gel reaction.

(B) The silicon compound having an amino group and an alkoxysilyl group is, for example, the following general formula (III)
Y R ¹⁰ _m
｜ ｜
HN-R ⁹ -Si (OR ¹¹ ) _3-m (III)
(In the above formula, R ⁹ is an alkylene group having 1 to 4 carbon atoms, R ¹⁰ and R ¹¹ are alkyl groups having 1 to 4 carbon atoms, Y is a hydrogen atom or an aminoalkyl group, and m is 1 or 0. )
The compound represented by these is mentioned.

Among the silicon compounds having an amino group and an alkoxysilyl group represented by the general formula (III), particularly 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-methyl-3-aminopropyltrimethoxysilane 3-aminopropylmethyldiethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, and N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane are preferred. These compounds can be used alone or in combination of two or more.
The (partial) hydrolyzate of a silicon compound having an amino group and an alkoxysilyl group is a product obtained by hydrolyzing a part or all of the silicon compound. The (partial) condensate is a condensate obtained by condensation reaction of a part or all of the hydrolyzate of the silicon compound, and a condensate of the condensate and a raw silicon compound that is not hydrolyzed. is there.

  (C) As the polyvinyl alcohol or polyvinyl alcohol copolymer, polyvinyl alcohol or a copolymer thereof in the description of the (B) polyvinyl alcohol component of the coating layer can be used. Examples of the polyvinyl alcohol copolymer include a vinyl alcohol-vinyl acetate copolymer, a vinyl alcohol-vinyl butyral copolymer, an ethylene-vinyl alcohol copolymer, and a polyvinyl alcohol polymer having a silyl group in the molecule. Among these, a vinyl alcohol-vinyl acetate copolymer, an ethylene-vinyl alcohol copolymer, and a polyvinyl alcohol polymer having a silyl group in the molecule are preferable, and an ethylene-vinyl alcohol copolymer is particularly preferable.

  Usually, the copolymerization ratio of vinyl alcohol is represented by the saponification degree, and the component (c) preferably has a saponification degree of 74 to 90 mol%. If the degree of saponification is less than 74 mol%, the moisture resistance of the planarization layer may be lowered and the gas barrier property may be poor. On the other hand, if the degree of saponification exceeds 90 mol%, the adhesion to the coating layer and the gas barrier layer and the blocking resistance may decrease.

The polyvinyl alcohol polymer having a silyl group in the molecule has a reactive alkoxysilyl group represented by the following general formula (IV).
(R ¹² O) _p —Si— (IV)
｜
R ¹³ _3-p
(In the above formula, R ¹² represents hydrogen or an alkyl group having 1 to 10 carbon atoms, an acyl group, or an alkali metal or alkaline earth metal; R ¹³ represents an alkyl group having 1 to 10 carbon atoms; Represents an integer of ~ 3)
The silyl group content is preferably 5 mol% or less, more preferably 1 mol% or less. When the content of the silyl group is increased, the coating agent for forming the planarizing layer tends to be easily gelled. The term “intramolecular” includes the end of the polymer. If the silyl group is bonded to the polyvinyl alcohol polymer by a non-hydrolyzable bond, the position, distribution state, etc. are not particularly limited. Absent.

The content ratio of the components (a) to (c) is preferably a weight ratio represented by the following formula (1).
1/9 <(c) / {(a) + (b)} <9/1 (1)
The weight of each component is determined on the assumption that all of the alkoxysilyl groups in the respective silicon compounds have undergone a condensation reaction after hydrolysis.
When the content ratio of the components (a) to (c) exceeds the upper limit of the formula (1), water resistance and chemical resistance may be deteriorated. On the other hand, when the content ratio of the components (a) to (c) is less than the lower limit of the formula (1), the gas barrier property may not be sufficiently improved.

The content ratio of the component (a) and the component (b) is a weight ratio represented by the following formula (2) in terms of adhesiveness, heat resistance, solvent resistance, water resistance, durability, and the like. Is preferred.
1/6 <(a ′) / (b ′) <6/1 (2)
(In the above formula, (a ′) represents the molar equivalent amount of the epoxy group contained in the component (a), and (b ′) represents the total molar equivalent amount of the amino group and the imino group contained in the component (b). )
The cured polymer obtained by crosslinking reaction of the components (a) to (c) may be added with a curing catalyst as necessary at the time of crosslinking.

The planarizing layer is preferably formed by coating. For example, in the case of a cured polymer obtained by crosslinking the components (a) to (c), the coating composition containing the components (a) to (c) and a solvent. It can be formed by applying a product on a coating layer and curing it by heating. Examples of the application method include commonly used methods such as dip coating, spray coating, flow coating, roll coating, bar coating, and spin coating.
The thickness of the planarizing layer is preferably 0.01 to 100 μm. In particular, in the case of a cured polymer, it takes time to cure if the film thickness exceeds 100 μm.

The planarization layer of the present invention preferably has a planarization layer peeling area of 10% or less as measured by a cross-cut test method. Here, the peeled area of the flattened layer measured by the crosscut test method means that 100 squares of 1 mm ² are formed on the flattened layer, a crosscut is performed in a grid pattern, and a cellophane having a width of 24 mm is formed thereon. Affixed with a tape (registered trademark manufactured by Nichiban Co., Ltd.), peeled off rapidly at a peeling angle of 180 °, and then observed on the peeled surface, defined as (number of peeled squares / 100 pieces) × 100 Is done.
In this evaluation method, since the flattening layer and the coating layer are cross-cut, peeling occurs at an interface having a weaker adhesive force between the base material-coating layer and the coating layer-planarizing layer. Therefore, after the peel test, it is determined which interface is peeled off with an optical microscope.

When the peeling area of a planarization layer exceeds an upper limit, the adhesiveness of the base film and planarization layer through a coating film layer is not enough, and sufficient gas barrier property may not be obtained. On the other hand, the smaller the lower limit, the better the adhesion between the coating layer and the flattening layer, and good gas barrier properties can be obtained, usually at least 0%.
As an achievement means for bringing the peeled area into the above-mentioned range, as the planarizing layer, an agent having high adhesion to the coating layer, for example, a silicon-containing resin and polyvinyl alcohol and a copolymer thereof, particularly preferably (a) to This is achieved by using a cured polymer obtained by crosslinking the component (c).

<Gas barrier processing (laminated) polyester film and gas barrier laminated polyester film>
The gas barrier processing (laminated) polyester film in the present invention refers to a polyester film having a layer structure at a stage before the gas barrier layer is laminated. Specifically, a layer structure in which a coating film layer is provided on at least one side of a base film made of polyester is referred to as a gas barrier processing polyester film. Moreover, in the case of the layer structure which has a coating film layer and a planarization layer on the at least single side | surface of the base film which consists of polyester, it calls the laminated polyester film for gas barrier processes. In the case of these layer configurations, the gas barrier processing (laminated) polyester film itself does not have sufficient gas barrier properties as an organic EL display substrate or an electronic paper substrate, but the gas barrier processing (laminated) polyester film has a gas barrier described later. When the layer is provided, it is possible to exhibit an excellent water vapor gas barrier property that has not been conventionally obtained. In the present invention, the laminated polyester film including the gas barrier layer is referred to as a gas barrier laminated polyester film.

<Gas barrier layer>
In the present invention, for the purpose of further enhancing the gas barrier property, a gas barrier laminated polyester film in which a gas barrier layer is laminated on at least one coating layer or at least one planarizing layer can be used. Examples of such a gas barrier layer include metal oxides or metal nitrides.

  Examples of the metal oxide include zinc oxide, silicon oxide, aluminum oxide, magnesium oxide, titanium oxide, indium oxide, tin oxide, indium tin oxide (ITO), tantalum oxide, zirconium oxide, and niobium oxide. May be used in combination. Among these metal oxides, zinc oxide, silicon oxide, aluminum oxide, and magnesium oxide are preferable as the main component, and silicon oxide is particularly preferable in terms of gas barrier properties and adhesiveness. These metal compounds may further contain at least one metal selected from the group consisting of iron, nickel, chromium, titanium, indium, tin, antimony, tungsten, molybdenum, and copper as a subordinate component. Carbon and fluorine may be appropriately contained for the purpose of improving the flexibility and transparency of the film. The main component can be added in a range of 70% by weight or more based on the weight of the gas barrier layer, and the subordinate component can be added in a range of 30% by weight or less based on the weight of the gas barrier layer.

The composition of silicon oxide is analyzed and determined by X-ray photoelectron spectroscopy, X-ray microspectroscopy, Auger electron spectroscopy, Rutherford backscattering, and the like. In terms of transmittance and flexibility, the average composition represented by SiO _x is preferably in the range of 1.5 to 2.0. When x is smaller than 1.5, flexibility and transparency may be deteriorated.
Examples of the metal nitride include aluminum nitride, silicon nitride, and boron nitride, and one kind or a combination thereof may be used.

The gas barrier layer is formed by a known sputtering method, vacuum deposition method, ion plating method, plasma CVD method or the like. In particular, the sputtering method can freely change the oxidation degree of the metal oxide, and has the advantage that the change in the film composition is small over a long period of time, and the film thickness uniformity and surface flatness are excellent.
The thickness of the metal oxide layer is preferably in the range of 2 to 200 nm. If the thickness of the metal oxide layer is less than 2 nm, it is difficult to form a film uniformly, and a portion where the film is not formed may occur and the gas barrier property may be impaired. On the other hand, when the thickness exceeds 200 nm, the transparency and flexibility are deteriorated to cause cracks, which may impair gas barrier properties.

<Humidity expansion coefficient αh>
The humidity expansion coefficient αh in the MD direction and the TD direction of the gas barrier laminated polyester film of the present invention is preferably in the range of 1 to 10 ppm /% RH, respectively. When the humidity expansion coefficient αh of the gas barrier laminated polyester film is in such a range, high gas barrier properties can be obtained. The humidity expansion coefficient αh in the MD direction and the TD direction is preferably in the range of 1 to 5 ppm /% RH, respectively. When the humidity expansion coefficient αh in the MD direction and the TD direction is less than the lower limit, it becomes necessary to add a large amount of a blend component having low hygroscopicity to the polyester constituting the base film, and the polyester film has these components. Heat resistant dimensional stability and transparency may be reduced. On the other hand, if the humidity expansion coefficient αh in the MD direction and the TD direction exceed the upper limit, the base film is hygroscopically expanded in a high humidity atmosphere, and the humidity change with various functional layers including a gas barrier layer laminated on the substrate Due to the difference in dimensional change with respect to the above, cracks may occur in various functional layers, so that the functional layers cannot sufficiently exhibit their original functions, and high gas barrier properties may not be obtained.

  In order to achieve these ranges of the humidity expansion coefficient αh, a layer structure including a gas barrier layer on at least one coating layer of the polyester base film, or flat on at least one coating layer of the polyester base film A layer structure in which a chemical layer and a gas barrier layer are laminated, and an increase in adhesion to both the base film and the gas barrier layer through the coating layer. When the layers are in close contact with each other, defects that serve as a water vapor transmission path are reduced. In addition, when some stress is applied, defects due to interfacial debonding or cracking in the gas barrier layer are less likely to occur, so the water vapor diffusion rate is slow, and the substrate film absorbs moisture even in a high humidity atmosphere. It becomes difficult to obtain a gas barrier laminate film having a range of the humidity expansion coefficient αh of the present invention.

More specifically, the humidity expansion coefficient αh of the present invention is i) a layer structure in which a coating layer, a planarizing layer, and a gas barrier layer are sequentially laminated on one side of a polyester base film as a layer structure, or made of polyester. A layer structure including at least a coating layer and a gas barrier layer in this order on both surfaces of the base film; ii) enhancing the adhesion of each of the above layers; specifically, the base film and the gas barrier layer or planarizing layer I) to iii) using a specific coating layer having an effect of improving the adhesiveness to iii) and iii) stretching the substrate film in the MD direction and the TD direction at a magnification of 2.9 times or more. ) Achieved by having everything. Moreover, in the case of a layer structure in which a coating layer, a flattening layer, and a gas barrier layer are sequentially laminated on one side of the polyester base film, it is further preferable that the lower limit of the thickness of the base film satisfies the above-mentioned range.
Furthermore, as means for achieving a humidity expansion coefficient αh of 5 ppm /% RH or less, the above-mentioned i) layer structure is a three-layer structure in which a coating film layer, a flattening layer, and a gas barrier layer are sequentially laminated on both sides of a polyester base film. It is preferable to have.

<Water vapor transmission rate>
The gas barrier laminate polyester film of the present invention preferably has a water vapor transmission rate of 0.1 g / m ² / day or less under high humidity conditions of 40 ° C. and 90% RH. Further, 40 ° C., the water vapor transmission rate of at 90% RH, more preferably 0.05g / m ² / day or less, particularly preferably not more than 0.01g / m ² / day. The lower limit of the water vapor transmission rate at 40 ° C. and 90% RH is not particularly limited, and is usually less than the detection limit of the MOCON method. The lower limit of the water vapor transmission rate when converted is preferably 10 × 10 ⁻⁶ g / m ² / day or more.

  The range of the water vapor transmission rate described above is that the components (A) to (C) are used as components of the coating film layer to improve the adhesion with the planarizing layer or the gas barrier layer, and the layer configuration is one side of the polyester base film. A layer configuration in which a coating layer, a planarization layer, and a gas barrier layer are laminated in order, or a layer configuration including at least a coating layer and a gas barrier layer in this order on both sides of a base film made of polyester. Achieved. The gas barrier layer itself is a layer having a gas barrier function. However, the presence of the gas barrier layer alone causes some defect that can be a gas transmission path, and the gas barrier property at the level required for organic EL display and electronic paper applications, that is, the above-described gas barrier layer. The gas barrier property represented by the water vapor transmission rate cannot be obtained. Then, the gas barrier property of the above-mentioned range is achieved by laminating | stacking the layer which consists of a metal oxide or a metal nitride on a base film through the coating-film layer and planarization layer of this invention. Furthermore, when the base film is ethylene naphthalate, higher gas barrier properties are achieved.

<Film forming method>
The polyester film of the present invention is obtained by melt-extruding polyester into a film shape, cooling and solidifying with a casting drum to form an unstretched film, and this unstretched film is stretched in the machine direction (MD) and width ( It is obtained by stretching biaxially at a magnification of 2.0 to 5.0 in the (TD) direction and heat-fixing at a temperature of (Tm-100) to (Tm-5) ° C. for 1 to 100 seconds.
The lower limit of the draw ratio in the MD direction and the TD direction is preferably 2.9 times or more in order to have the Young's modulus and the humidity expansion coefficient αh of the present invention. The upper limit of the draw ratio in the MD direction and the TD direction is preferably 3.9 times or less in order to have the Young's modulus of the present invention and the heat shrinkage rate at 200 ° C.

Stretching can be performed by a generally used method, for example, a method using a roll or a method using a stenter, and the MD direction and the TD direction may be stretched simultaneously, or the MD direction and the TD direction may be sequentially stretched. In the case of sequential stretching, the coating layer can be provided by a method in which an aqueous coating solution is applied to a uniaxially oriented film stretched in one direction, and stretched in the other direction as it is and heat-set. As a coating method of the coating layer, any known coating method can be applied. For example, a roll coating method, a gravure coating method, a roll brush method, a spray coating method, an air knife coating method, an impregnation method, and a curtain coating method can be used alone or in combination. The coating amount is preferably 0.5 to 20 g, more preferably 1 to 10 g per 1 m ² of the running film. The aqueous liquid is preferably used as an aqueous dispersion or emulsion.

Furthermore, when performing a relaxation | loosening process, it is effective to perform heat processing in the temperature of (X-80) -X degreeC of a film. Here, X represents the heat setting temperature. As a relaxation treatment method, i) a method in which both ends of the film are cut off in the middle of the heat setting zone and the take-up speed is reduced with respect to the supply speed of the film, between the heat setting and the roll winding, ii) A method of heating with an IR heater between two transport rolls of different speeds, iii) A method of transporting a film on the heat transport roll and reducing the speed of the transport roll after the heat transport roll, iv) Blowing hot air after heat fixing There is a method of reducing the take-up speed rather than the supply speed while conveying the film on the nozzle. Moreover, after winding with a film forming machine, the method of performing a relaxation process by decelerating the roll speed on the winding side from the roll speed on the film supply side while heating the film is also mentioned. Examples of the heating means in this case include a method of heating a roll and a method using a heating oven or an IR heater.
Any method may be used for the relaxation treatment, and it is preferable to perform the relaxation treatment by setting the rate of reduction of the take-up side speed to 0.1 to 10% with respect to the supply-side speed.

In order to obtain the polyester film having the heat shrinkage characteristic at 200 ° C. of the present invention, the film is stretched in the MD direction and the TD direction at a stretching ratio of 3.9 times or less, and (Tm-100) to (Tm- 5) It is achieved by performing heat setting at a temperature of 1 ° C. for 1 to 100 seconds and then performing a relaxation treatment at a temperature of (X-80) to X ° C.
A planarization layer is formed by apply | coating a planarization composition solution on the coating film layer of the obtained polyester film, and performing heat processing in a 100-150 degreeC temperature range. Further, a gas barrier layer is formed on the coating layer or the planarizing layer by using a sputtering method or the like.

<Application>
The polyester film for gas barrier processing of the present invention is suitably used as a substrate film for an image display device such as an organic EL display or electronic paper, in which gas barrier properties and transparency are strongly required. It can also be used as a substrate film for liquid crystal displays, organic TFTs and the like.
Moreover, since the gas barrier laminated polyester film of the present invention is excellent in gas barrier properties and transparency, it is suitably used as an image display device that requires these characteristics, such as an organic EL display substrate and an electronic paper substrate. It can also be used as a liquid crystal display substrate or an organic TFT substrate.

  Hereinafter, the present invention will be described based on examples. Each characteristic value and evaluation method were measured and evaluated by the following methods. In addition, a film sample refers to the film which consists of a polyester base film and a coating film layer, when the coating film layer is formed. Moreover, unless otherwise indicated, the part and% in an Example mean a weight part and weight%, respectively.

(1) Film thickness Film sample thickness was measured at 30 g of needle pressure using an electronic micrometer (trade name “K-312A type” manufactured by Anritsu Corporation).

(2) Haze, total light transmittance According to JIS standard K7105, the total light transmittance Tt (%) and the scattered light transmittance Td (%) of the film sample are obtained, and haze ((Td / Tt) × 100) (%) Is calculated.
Haze A: 1.5% or less B: More than 1.5% Total light transmittance A: 85% or more B: Less than 85%

(3) Heat shrinkage rate Marks are attached to film samples at intervals of 30 cm, heat treatment is performed in an oven at a predetermined temperature without applying a load, the distance between the marks after heat treatment is measured, and MD direction and TD direction are measured. The thermal shrinkage rate was calculated by the following formula.
Thermal contraction rate (%) = ((distance between the pre-heat treatment gauge points−distance between the heat treatment gauge points) / distance between the heat treatment gauge points) × 100
The heat shrinkage rate after heat treatment at 150 ° C. for 30 minutes was evaluated according to the following criteria.
A: Thermal shrinkage of each of MD and TD at 150 ° C. ≦ 0.05%
B: 0.05% <MD, TD 150 ° C. heat shrinkage ratio ≦ 0.1%
C: 0.1% <MD and TD, 150 ° C. thermal shrinkage rate Each of the thermal shrinkage rates after heat treatment at 200 ° C. × 10 minutes was evaluated according to the following criteria.
A: Thermal shrinkage of each of MD and TD at 200 ° C. ≦ 0.2%
B: 0.2% <MD, TD 200 degreeC heat shrinkage of each

(4) Thickness of the coating layer A small piece of film is embedded in an epoxy resin (trade name “Epomount” manufactured by Refine Tech Co., Ltd.), and the total thickness of the embedded resin is 50 nm using a Microtome 2050 manufactured by Reichert-Jung. The film was sliced and observed with a transmission electron microscope (LEM-2000) at an acceleration voltage of 100 KV and a magnification of 100,000, and the thickness of the coating layer was measured.

(5) Average particle diameter of particles in the coating layer The same operation as the measurement of the thickness of the coating layer was performed to measure the particle size of 100 particles, and the average value was taken as the average particle size.

(6) Scratch resistance of coating film layer Using a film sample cut to a width of 20 mm, the coating film layer surface of the film was applied to a cylindrical stainless steel fixing bar having a diameter of 10 mm, and was run for 80 m with a load of 200 g applied. Then, the white powder of the coating film adhering to the bar is observed, and the abrasion resistance is evaluated as follows.
A: No white powder adheres to the bar ...... Good abrasion resistance B: A small amount of white powder adheres to the bar ...... Slightly poor abrasion resistance

(7) Blocking property Using two film samples cut to a width of 50 mm, the coating layer surface and the surface on which the coating layer is not applied are overlapped. After treating for 17 hours at 60 ° C. × 80% RH under a load of 50 kg / cm ² , the peel strength between the coating layer surface and the non-coating layer surface is measured, and blocking resistance is evaluated as follows.
A: Peeling force ≦ 10 g: Good blocking resistance B: 10 g <Peeling force ≦ 30 g—Slightly poor blocking resistance C: 30 g <Peeling force: Poor blocking resistance

(8) Adhesiveness with flattening layer and substrate layer 100 parts of ethylene-vinyl alcohol copolymer (manufactured by Kuraray Co., Ltd., product name “EVAL”, hereinafter sometimes abbreviated as EVOH), 720 parts of water, After dissolving in 1080 parts of n-propanol mixed solvent with heating, 0.1 part of a leveling agent (product name “SH30PA” manufactured by Toray Dow Corning Co., Ltd.) and 39 parts of acetic acid were added to this solution, and then 2- (3,4 -Epoxycyclohexyl) 211 parts of trimethylsilane was added and stirred for 10 minutes. Further, 77 parts of 3-aminopropyltrimethoxysilane was added to this solution and stirred for 3 hours to obtain a coating composition. This coating composition was coated on the coating layer surface of the polyester film and subjected to heat treatment at 130 ° C. for 3 minutes to form a flattened layer having a thickness of 2 μm.
After cross-cutting cross-cuts (100 squares of 1 mm ² ) on the flattened layer surface, 24 mm wide cellophane tape (manufactured by Nichiban Co., Ltd.) is pasted on it and peeled off rapidly at a 180 ° peeling angle. The peeled surface was observed and evaluated according to the following criteria. In this evaluation method, since the flattening layer and the coating layer are cross-cut, peeling occurs at an interface having a weaker adhesive force between the base material-coating layer and the coating layer-planarizing layer. Therefore, after the peeling test, the presence of fine particles contained in the coating layer was confirmed with an optical microscope, and it was judged at which interface the peeling occurred.
A: Peeling area is less than 10% ·························································· B: Peeling area is 10% or more and less than 40% Very bad

(9) Humidity expansion coefficient αh
Cut out a film sample piece with a length of 15 mm and a width of 5 mm, set it on TMA3000 manufactured by Vacuum Riko, and maintain a constant humidity of 30% RH × 16 hr and a humidity of 70% RH × 16 hr in a nitrogen atmosphere at 30 ° C. And the sample length under each humidity condition is measured, and the humidity expansion coefficient is calculated by the following equation (3). Note that the humidity expansion coefficient in the MD direction is the measurement direction in the longitudinal direction of the film, and the humidity expansion coefficient in the TD direction is the measurement direction in the horizontal direction of the film. Ten film samples were measured in each direction, and the average value was defined as αh.
αh = {(L ₂ −L ₁ ) / (L ₁ × ΔH)} (3)
Here, in the above formula, L ₁ is the sample piece length (mm) when the humidity is 30% RH, L ₂ is the sample piece length (mm) when the humidity is 70% RH, and ΔH is 40 (= 70-30)% RH, respectively. Show.
In Examples 1 to 31 and Comparative Examples 2 to 8 described in Tables 1 and 2, according to the evaluation method of (8) adhesion and (10) gas barrier properties, a coating layer and a flat surface on one side of the polyester base film Αh was measured using a laminated film in which a chemical layer and a gas barrier layer were laminated. In Examples 32 to 35 and Comparative Examples 9 and 10 described in Table 3, αh was measured using films having a laminated structure described in Table 3, respectively.
A: 1 ppm /% RH ≦ αh <5 ppm /% RH ・ ・ Extremely good dimensional stability B: 5 ppm /% RH ≦ αh ≦ 10 ppm /% RH ・ ・ Good dimensional stability C: 10 ppm /% RH <αh ≦ 15 ppm / % RH ・ ・ Dimensional stability failure D: 15ppm /% RH <αh ・ ・ Dimensional stability extremely poor

(10) Gas barrier properties (water vapor barrier properties (Evaluation Method 1))
(8) On the flattening layer formed on the coating layer according to the adhesion evaluation method, a SiO ₂ film having a thickness of 30 nm is formed by sputtering, and 40 ° C. using Permantlan W1A manufactured by MOCON. The water vapor transmission rate in a 90 RH% atmosphere was measured, and the gas barrier properties were evaluated according to the following criteria.
A: water vapor permeability ≦ 0.05g / m ² / day ······ barrier very good ^{B: 0.05g / m 2 / day} < water vapor permeability ≦ 0.1g / m ² / day · barrier good C: 0.1 g / m ² / day <water vapor transmission rate ...... Poor barrier property

(11) Gas barrier properties (water vapor barrier properties (evaluation method 2))
Using the film samples having the layer structure described in each Example and Comparative Example, the water vapor transmission rate in an atmosphere of 40 ° C. and 90 RH% was measured using Permantlan W1A manufactured by MOCON, and the gas barrier property was evaluated according to the following criteria. did.
A: water vapor permeability ≦ 0.05g / m ² / day ······ barrier very good ^{B: 0.05g / m 2 / day} < water vapor permeability ≦ 0.1g / m ² / day · barrier good C: 0.1 g / m ² / day <water vapor transmission rate ...... Poor barrier property

(12) Water vapor barrier property after high-temperature heat history Heat treatment is performed at 200 ° C. for 10 minutes using a film having the same layer configuration as (10) or (11), and then 40 ° C. using Permatran W1A manufactured by MOCON. The water vapor transmission rate of the film in a 90 RH% atmosphere was measured and evaluated according to the following criteria.
A: water vapor permeability ≦ 0.05g / m ² / day ······ barrier very good ^{B: 0.05g / m 2 / day} < water vapor permeability ≦ 0.1g / m ² / day · barrier good C: 0.1 g / m ² / day <water vapor transmission rate ...... Poor barrier property

[Example 1]
Establish 100 parts of dimethyl naphthalene-2,6-dicarboxylate and 60 parts of ethylene glycol with 0.03 part of manganese acetate tetrahydrate as a transesterification catalyst and gradually raise the temperature from 150 ° C. to 238 ° C. for 120 minutes. An exchange reaction was performed. In the middle, when the reaction temperature reached 170 ° C., trimethyl phosphate (135 ° C. in ethylene glycol, heat-treated at 0.11 to 0.16 MPa for 5 hours: 0.023 part in terms of trimethyl phosphate) ) And 0.024 parts of antimony trioxide was added after the transesterification reaction.
Thereafter, the reaction product is transferred to a polymerization reactor, heated to 290 ° C., and subjected to a polycondensation reaction under a high vacuum of 27 Pa or less, and has an intrinsic viscosity of 0.61 dl / g and substantially no particles. Polyethylene-2,6-naphthalenedicarboxylate was obtained.

The polyethylene-2,6-naphthalenedicarboxylate pellets were dried at 170 ° C. for 6 hours, then fed to an extruder hopper, melted at a melting temperature of 305 ° C., and cooled at a surface temperature of 60 ° C. through a 2 mm slit die. The film was extruded on a drum and quenched to obtain an unstretched film. The obtained unstretched film was preheated at 120 ° C., and further heated by a 900 ° C. IR heater from above 15 mm between low-speed and high-speed rolls and stretched 3.1 times in the longitudinal direction. In order to form a coating film layer on one side of the film after the longitudinal stretching, an aqueous liquid having a solid content concentration of 4% by weight having the following composition was applied by a roll coater, and then supplied to a tenter. In the horizontal direction. The film was stretched 3.5 times.
The obtained biaxially oriented film was heat-fixed at a temperature of 240 ° C. for 40 seconds, and a polyester film having a thickness of 100 μm was wound up. Then, using a heating zone with an IR heater, the treatment temperature was 200 ° C. and the relaxation rate was 1.0%. A relaxation treatment was performed to obtain a stretched film (film sample).

The flattening layer and the gas barrier layer are laminated in accordance with the methods described in (8) Adhesion evaluation and (10) Gas barrier property evaluation, respectively, and the coating film layer, the flattening layer, and the gas barrier layer are sequentially laminated on one side of the base film. A film having the structure described above was obtained. The properties of the obtained film are shown in Tables 1, 2, and 3.
Excellent adhesion to both the flattening layer and the base film was obtained, the coating layer was excellent in durability, and the laminated film obtained by the barrier processing had excellent gas barrier properties.

<Coating layer component>
(A) Copolyester resin: a copolymerized polyester (Tg = Tole = 60 mol% of terephthalic acid, 36 mol% of isophthalic acid and 4 mol% of 5-Na sulfoisophthalic acid, 60 mol% of ethylene glycol and 40 mol% of neopenthiglycol) 30 ° C., hereinafter abbreviated as E.) 55% by weight
(B) Polyvinyl alcohol: Polyvinyl alcohol having a saponification degree of 74-80% (hereinafter abbreviated as J) 16% by weight
(C) Fine particles: spherical silica particles having an average particle size of 80 nm (hereinafter abbreviated as N) 10% by weight
(D) Crosslinking agent: N, N, N ′, N′-tetraglycidylmetaxylylenediamine (hereinafter abbreviated as R) of epoxy resin 10% by weight
(E) Wetting agent: 9% by weight of polyoxyethylene lauryl ether

[Comparative Example 1]
It carried out similarly to Example 1 except not apply | coating the aqueous liquid which forms a coating-film layer. The properties of the obtained film are shown in Table 1.
The planarization layer and the gas barrier layer were each formed on one side in the same manner as in the evaluation of Example 1, and the planarization layer was directly formed on one side of the polyester substrate film.

[Examples 2 to 13 , 15 , 17 to 18 , Comparative Examples 2 to 7 , 10 to 12 ]
It carried out like Example 1 except changing the kind and ratio of (A)-(D) component which comprise a coating-film layer as shown in Table 1. The properties of the obtained film are shown in Table 1. As is apparent from the results shown in Table 1, each example has excellent adhesion to both the flattening layer and the base film, and the coating layer is excellent in durability. The obtained laminated film had excellent gas barrier properties.

In Table 1, the following copolyesters were used as types (A) to (I) of the (A) copolyester resin.
F: <acid component> 2,6-Naphthalenedicarboxylic acid 20 mol%, isophthalic acid 76 mol%, 5-K sulfoterephthalic acid 4 mol% / <diol component> ethylenepolyester 50 mol%, neopentylglycol 50 mol% copolyester (Tg = 42 ℃)
G: <Acid component> Copolyester (Tg = 65) of 70 mol% terephthalic acid, 24 mol% isophthalic acid, 6 mol% 5-Na sulfoterephthalic acid / <diol component> 60 mol% ethylene glycol, 3 mol% diethylene glycol, 37 mol% neopentyl glycol ℃)
H: <acid component> terephthalic acid 16 mol%, isophthalic acid 80 mol%, 5-Na sulfoterephthalic acid 4 mol% / <diol component> diethylene glycol 5 mol%, 1,4-butanediol 60 mol%, neopenthiglycol 35 mol% copolyester (Tg = 17 ° C)
I: <acid component> 2,6-Naphthalenedicarboxylic acid 77 mol%, terephthalic acid 19 mol%, 5-K sulfoterephthalic acid 4 mol% / <diol component> ethylene glycol 90 mol%, neopentylene glycol 10 mol% copolyester (Tg = 98 ° C)

Moreover, the following compound was used for the types K-M of (B) polyvinyl alcohol, respectively.
K: Polyvinyl alcohol having a saponification degree of 85-90 mol% L: Polyvinyl alcohol having a saponification degree of 91-95 mol% M: Polyvinyl alcohol having a saponification degree of 65-72 mol%

(C) The following compounds were used for the types O to Q of the fine particles.
O: spherical silica particles having an average particle diameter of 60 nm P: spherical silica particles having an average particle diameter of 120 nm Q: colloidal silica particles having an average particle diameter of 10 nm

(D) Types S to U of the crosslinking agent used the following compounds, respectively.
S: Melamine-based resin: Trimethoxymethylmelamine (trimethylolmelamine etherified with methanol)
T: Copolymer having an oxazoline group .. Copolymer of 2-propenyl-oxazoline 60 mol% and methyl methacrylate 40 mol% U: dimethylolethylene urea

[ Comparative Example 13 ]
A film was obtained in the same manner as in Example 1 except that the relaxation treatment at 200 ° C. was not performed. The properties of the obtained film are shown in Table 2. Although there was a portion lacking in high-temperature dimensional stability, a film having excellent gas barrier properties and excellent transparency was obtained.

[Examples 22 to 24]
A film was obtained in the same manner as in Example 1 except that the thickness of the film was different. The properties of the obtained film are shown in Table 2. The obtained film was excellent in transparency, dimensional stability, and gas barrier properties of the substrate.

[Example 25]
A film was obtained in the same manner as in Example 1 except that the draw ratio was different. The properties of the obtained film are shown in Table 2. The obtained film was excellent in transparency, dimensional stability, and gas barrier properties of the substrate.

[ Comparative Example 14 ]
A film was obtained in the same manner as in Example 1 except that the draw ratio was different. The properties of the obtained film are shown in Table 2. Although the obtained film had a portion lacking in high-temperature dimensional stability, it was excellent in transparency and gas barrier property of the substrate.

[ Comparative Example 15 ]
96 parts of dimethyl terephthalate, 58 parts of ethylene glycol and 0.038 part of manganese acetate were charged into the reactor, respectively, and the ester exchange reaction was carried out while distilling methanol until the internal temperature reached 240 ° C. with stirring. After the transesterification reaction was completed by adding 0.097 part of trimethyl phosphate, 0.041 part of antimony trioxide was added. Subsequently, the temperature of the reaction product was raised, and finally polycondensation was performed under conditions of 280 ° C. under high vacuum to obtain a chip of polyethylene terephthalate having an intrinsic viscosity ([η]) of 0.64.

Next, this polyethylene terephthalate chip was dried at 170 ° C. for 3 hours, then supplied to a twin-screw extruder, melt-kneaded at 280 ° C., and rapidly cooled and solidified to obtain a master chip.
The polyethylene terephthalate pellets were dried at 160 ° C. for 3 hours, then supplied to an extruder hopper, melted at a melting temperature of 295 ° C., and rapidly cooled and solidified on a cooling drum maintained at 20 ° C. to obtain an unstretched film. The unstretched film was stretched 3.1 times in the machine direction at 95 ° C., and then the same coating agent as in Example 1 was applied on one side so that the thickness after drying was 0.1 μm. After stretching 3.5 times in the direction, heat treatment was performed at 230 ° C. to obtain a biaxially stretched film having a thickness of 100 μm. The properties of the obtained film are shown in Table 2. Although the high-temperature dimensional stability was not sufficient, a film with good transparency and gas barrier properties of the substrate could be obtained.

[ Comparative Example 16 ]
A film was obtained in the same manner as in Comparative Example 15 except that a relaxation treatment was performed at a treatment temperature of 160 ° C. and a relaxation rate of 1.0% using a heating zone with an IR heater. The properties of the obtained film are shown in Table 2. Although the dimensional stability at 200 ° C. was not sufficient, a film having good dimensional stability at 150 ° C. and good transparency and gas barrier properties of the substrate could be obtained.

[ Comparative Example 17 ]
A film was obtained in the same manner as in Comparative Example 15 except that the thickness of the film was different. The properties of the obtained film are shown in Table 2. A film excellent in transparency was obtained although it lacked high-temperature dimensional stability and barrier properties of the substrate.

[Comparative Example 8]
A film was obtained in the same manner as in Example 21 except that 0.1% by weight of spherical silica particles having an average particle diameter of 0.35 μm was blended with polyethylene-2,6-naphthalenedicarboxylate. The properties of the obtained film are shown in Table 2. The film lacked optical properties because it contained inert particles as a lubricant.

[Example 30]
A laminated film was obtained in the same manner as in Example 1 except that a coating layer, a planarizing layer, and a gas barrier layer were provided on both sides of the polyester film. Table 3 shows the properties of the obtained laminated film.

[Example 31]
A laminated film was obtained in the same manner as in Example 30 except that no planarizing layer was provided on both sides. Table 3 shows the properties of the obtained laminated film.

[Example 32]
A laminated film was obtained in the same manner as in Example 1 except that the planarizing layer was not provided. Table 3 shows the properties of the obtained laminated film.

[Example 33]
A laminated film was obtained in the same manner as in Example 1 except that the draw ratio was different. Table 3 shows the properties of the obtained laminated film.

[Comparative Example 9]
A laminated film was obtained in the same manner as in Example 33 except that the coating layer and the flattening layer were not provided. Table 3 shows the properties of the obtained laminated film.

  The polyester film for gas barrier processing of the present invention has a high gas barrier property when a gas barrier layer is further provided, and also has high transparency and slipperiness. It can be suitably used as a substrate film such as paper. Moreover, since the gas barrier laminated polyester film of the present invention has high gas barrier properties and also has high transparency and slipperiness, it is suitably used as an organic EL display substrate and electronic paper substrate that require these characteristics. be able to.

Claims (21)

A port Li ester film at least one surface coating layer is provided of a base film made of polyester, a polyester is polyethylene naphthalate constituting the substrate film, the reference coating film layer weight of a coating layer (A) 50 to 80% by weight of a copolyester resin having a glass transition point of 20 to 90 ° C. , (B) 10 to 30% by weight of polyvinyl alcohol having a saponification degree of 74 to 90 mol% , and (C) fine particles 3-25% by weight, and (D) a crosslinking agent containing 1 to 20 wt%, total light transmittance of the polyester film 85% or more, the haze is 1.5% or less, and 200 ° C. × heat shrinkage MD direction of 10 minutes, the organic EL display Po Li ester film substrate, wherein less der Rukoto 0.2% TD direction, respectively. (C) an organic EL display Po Li ester film substrate according to claim 1 having an average particle size of the fine particles is 20 to 100 nm. (D) crosslinking agent, oxazoline group-containing polymer, urea-based resin, an organic EL display substrate Po Li ester film according to claim 1 or 2 is at least one selected from the group consisting of melamine resins and epoxy resins . 150 thermal shrinkage at ° C. × 30 minutes MD direction, Po Li ester film for an organic EL display substrate according to any one of claims. 1 to 3 TD directions, respectively 0.1% or less. Polyethylene naphthalate - DOO is port for organic EL display substrate according to any one of claims 1-4 ethylene-2,6 is naphthalene dicarboxylate 90 mol% or more based on the moles of total repeating structural units Riesuteru the film. At least one coating gas barrier layer further stacked organic EL display gas barrier laminated polyester substrate film on layer of an organic EL display substrate Po Li ester film of any of claims 1-5. The gas barrier layered polyester film for an organic EL display substrate according to claim 6 , wherein the gas barrier layer is a metal oxide or a metal nitride. The gas barrier layered polyester film for an organic EL display substrate according to claim 6 or 7 , wherein the gas barrier layer contains SiOx (1.5≤x≤2.0) as a main component. The gas expansion laminated polyester film for organic EL display substrates according to any one of claims 6 to 8 , wherein the humidity expansion coefficient αh in the MD direction and the TD direction is 1 to 10 ppm /% RH, respectively. The gas-barrier laminated polyester film for an organic EL display substrate according to any one of claims 6 to 9 , wherein a water vapor transmission rate at 40 ° C and 90% RH is 0.1 g / m ² / day or less. The organic EL display substrate containing the gas barrier property laminated polyester film for organic EL display substrates in any one of Claims 6-10 . At least one coating planarizing layer further stacked organic EL display product layer polyester film substrate was on the layer of the organic EL display substrate Po Li ester film of any of claims 1-5. Planarization layer comprises a polyvinyl alcohol, an organic EL display product layer polyester film substrate according to claim 12. (B) an epoxy silicon compound selected from the group consisting of (a) a silicon compound having an epoxy group and an alkoxysilyl group, a (partial) hydrolyzate thereof, a (partial) condensate thereof, and a mixture thereof; ) A silicon compound having an amino group and an alkoxysilyl group, its (partial) hydrolyzate, its (partial) condensate, and a mixture thereof, and (c) polyvinyl alcohol or polyvinyl the organic EL display product layer polyester film substrate according to claim 12 or 13 which is a cured polymer layer formed by the alcohol copolymer crosslinked reaction. The organic EL display product layer polyester film substrate according to any one of claims 12-14 peeling area of the planarizing layer is 10% or less as measured by cross-cut test method. Organic least one organic EL display gas barrier laminated polyester substrate film for the gas barrier layer is further laminated on the planarizing layer of an EL display product layer polyester film substrate according to claim 12-15. The gas barrier layered polyester film for an organic EL display substrate according to claim 16 , wherein the gas barrier layer is a metal oxide or a metal nitride. The gas barrier layered polyester film for an organic EL display substrate according to claim 16 or 17 , wherein the gas barrier layer contains SiOx (1.5≤x≤2.0) as a main component. The gas barrier laminated polyester film for organic EL display substrates according to any one of claims 16 to 18 , wherein the humidity expansion coefficient αh in the MD direction and the TD direction is 1 to 10 ppm /% RH, respectively. 40 ° C., the organic EL display gas barrier laminate polyester film substrate according to any one of claims 16-19 water vapor transmission rate is less than 0.1g ^/ m 2 ^/ day at 90% RH. An organic EL display substrate comprising the gas barrier laminate polyester film for an organic EL display substrate according to any one of claims 16 to 20 .